Huet Sylvie

Irstea − Lisc
9 avenue Blaise Pascal − CS 20085
63178 Aubière − France
+33 4 73 44 06 15
Contact

Research scientist Social simulation, social psychology, attitude dynamics, demography, innovation diffusion

Invest(ed) in the following projects:

European project PRIMA (2007-2010) - Prototypical Policy Impact of Multifunctional Activities in Rural Municipalities
European project IDARI (2003-2006) - Integrated Development of Agricultural and Rural Institutions
European project FIRMA (2000-2003) - Freshwater Integrated Resource management with Agents
European project IMAGES (1997-2001) - Improving Agri-Environmental Policies : a Simulation Approach to the Role of the Cognitive Properties of Farmers and Institutions
European project BED (1997-1999)- Test and engine fault diagnosis bench for tractors and agricultural machinery.

Publications

Journal Articles (20)

J.D. Mathias, S. Huet, G. Deffuant
An energy-like indicator to assess opinion resilience
Physica A-Statistical Mechanics and its Applications 473, 2017
abs doi web bib

Using the bounded-confidence model, with fixed uncertainties and extremists, we investigate how resilient the moderate mean opinion of a population is to the arrival in it of a new group of agents, when the energy of the opinion of this group extremeness × group size) is varied. We say moderate mean opinion is resilient when, even though it may become temporarily more extreme after the arrival of the new agents, it later recovers its moderate value. We show that such resilience is displayed up to a threshold value of the equivalent energy of the group. We also show that when the agent-based model spontaneously converges to a single extreme, then this energy threshold is nill.
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@article{PUB00052559, author = {Mathias, J.D. and Huet, S. and Deffuant, G.}, title = {An energy-like indicator to assess opinion resilience}, title = {Un indicateur type énergie pour évaluer la résilience d'une opinion}, journal = {Physica A-Statistical Mechanics and its Applications}, volume = {473}, pages = {501-510}, url = {http://cemadoc.irstea.fr/cemoa/PUB00052559}, doi = {http://dx.doi.org/10.1016/j.physa.2016.12.035}, year = {2017}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {Using the bounded-confidence model, with fixed uncertainties and extremists, we investigate how resilient the moderate mean opinion of a population is to the arrival in it of a new group of agents, when the energy of the opinion of this group extremeness × group size) is varied. We say moderate mean opinion is resilient when, even though it may become temporarily more extreme after the arrival of the new agents, it later recovers its moderate value. We show that such resilience is displayed up to a threshold value of the equivalent energy of the group. We also show that when the agent-based model spontaneously converges to a single extreme, then this energy threshold is nill.}, }
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J.D. Mathias, S. Huet, G. Deffuant
Bounded confidence model with fixed uncertainties and extremists: The opinions can keep fluctuating indefinitely
JASSS-The Journal of Artificial Societies and Social Simulation 19 (1), 2016
abs doi web bib

The bounded confidence model and its variants applied to moderate and extremist agents exhibit three types of attractors: central clusters, double extreme and single extreme clusters. These attractors are observed when the models include a dynamics on the uncertainties tending to decrease the moderate uncertainties when interacting with extremists. We show here that a new stationary state appears when the uncertainties are fixed, for large uncertainties of the moderates. In this stationary state, the opinions of moderate agents keep fluctuating without clustering, altogether forming a stable density which shape changes significantly when the parameters vary.
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@article{PUB00046748, author = {Mathias, J.D. and Huet, S. and Deffuant, G.}, title = {Bounded confidence model with fixed uncertainties and extremists: The opinions can keep fluctuating indefinitely}, journal = {JASSS-The Journal of Artificial Societies and Social Simulation}, volume = {19}, number = {1}, pages = {15}, url = {http://jasss.soc.surrey.ac.uk/19/1/6.html}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00046748}, doi = {http://dx.doi.org/10.18564/jasss.2967}, year = {2016}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {The bounded confidence model and its variants applied to moderate and extremist agents exhibit three types of attractors: central clusters, double extreme and single extreme clusters. These attractors are observed when the models include a dynamics on the uncertainties tending to decrease the moderate uncertainties when interacting with extremists. We show here that a new stationary state appears when the uncertainties are fixed, for large uncertainties of the moderates. In this stationary state, the opinions of moderate agents keep fluctuating without clustering, altogether forming a stable density which shape changes significantly when the parameters vary.}, }
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M. Lenormand, S. Huet, F. Gargiulo
Generating French virtual commuting networks at the municipality level
Journal of Transport and Land Use, 2014
abs doi web bib

We aim to generate virtual commuting networks in the rural regions of France in order to study the dynamics of their municipalities. Since it will be necessary to model small commuting flows between municipalities with a few hundred or thousand inhabitants, we have opted for the stochastic model presented by Gargiulo et al. (2012). This model reproduces various possible complete networks using an iterative process, stochastically selecting a workplace in the region for each commuter living in the municipality of a region. The choice is made considering the job offers in each municipality of the region and the distance to all of the possible destinations. This paper will present methods for adapting and implementing this model to generate commuting networks between municipalities for regions in France. We address three different issues: How can we generate a reliable virtual commuting network for a region that is highly dependent on other regions for the satisfaction of its residents demands for employment? What about a convenient deterrence function? How can we calibrate the model when detailed data is not available? Our solution proposes an extended job search geographical base for commuters living in the municipalities; we compare two different deterrence functions and we show that the parameter is a constant for network linking municipalities in France.
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@article{PUB00040106, author = {Lenormand, M. and Huet, S. and Gargiulo, F.}, title = {Generating French virtual commuting networks at the municipality level}, title = {Générer les réseaux de navettage français au niveau municipalité}, journal = {Journal of Transport and Land Use}, pages = {13}, url = {https://www.jtlu.org/index.php/jtlu/article/view/360}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00040106}, doi = {http://dx.doi.org/http://dx.doi.org/10.5198/jtlu.v7i1.360}, year = {2014}, affiliation = {IFISC MAJORCA ESP ; IRSTEA CLERMONT FERRAND UR LISC FRA ; UNIVERSITE DE NAMUR NAXYS BEL}, abstract = {We aim to generate virtual commuting networks in the rural regions of France in order to study the dynamics of their municipalities. Since it will be necessary to model small commuting flows between municipalities with a few hundred or thousand inhabitants, we have opted for the stochastic model presented by Gargiulo et al. (2012). This model reproduces various possible complete networks using an iterative process, stochastically selecting a workplace in the region for each commuter living in the municipality of a region. The choice is made considering the job offers in each municipality of the region and the distance to all of the possible destinations. This paper will present methods for adapting and implementing this model to generate commuting networks between municipalities for regions in France. We address three different issues: How can we generate a reliable virtual commuting network for a region that is highly dependent on other regions for the satisfaction of its residents demands for employment? What about a convenient deterrence function? How can we calibrate the model when detailed data is not available? Our solution proposes an extended job search geographical base for commuters living in the municipalities; we compare two different deterrence functions and we show that the parameter is a constant for network linking municipalities in France.}, }
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G. Deffuant, T. Carletti, S. Huet
The Leviathan Model: Absolute dominance, generalised distrust, small worlds and other patterns emerging from combining vanity with opinion propagation
JASSS-The Journal of Artificial Societies and Social Simulation 16 (1), 2013
abs web bib

We propose an opinion dynamics model that combines processes of vanity and opinion propagation. The interactions take place between randomly chosen pairs. During an interaction, the agents propagate their opinions about themselves and about other people they know. Moreover, each individual is subject to vanity: if her interlocutor seems to value her highly, then she increases her opinion about this interlocutor. On the contrary she tends to decrease her opinion about those who seem to undervalue her. The combination of these dynamics with the hypothesis that the opinion propagation is more efficient when coming from highly valued individuals, leads to different patterns when varying the parameters. For instance, for some parameters the positive opinion links between individuals generate a small world network. In one of the patterns, absolute dominance of one agent alternates with a state of generalised distrust, where all agents have a very low opinion of all the others (including themselves). We provide some explanations of the mechanisms behind these emergent behaviors and finally propose a discussion about their interest.
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@article{PUB00038235, author = {Deffuant, G. and Carletti, T. and Huet, S.}, title = {The Leviathan Model: Absolute dominance, generalised distrust, small worlds and other patterns emerging from combining vanity with opinion propagation }, title = {Le modèle Léviathan : domination absolue, défiance, "petits mondes" et autres patterns émergeant de la combinaison vanité - propagation d'opinion}, journal = {JASSS-The Journal of Artificial Societies and Social Simulation}, volume = {16}, number = {1}, pages = {32}, url = {http://jasss.soc.surrey.ac.uk/16/1/5.html}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00038235}, year = {2013}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; UNIVERSITY OF NAMUR BEL ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {We propose an opinion dynamics model that combines processes of vanity and opinion propagation. The interactions take place between randomly chosen pairs. During an interaction, the agents propagate their opinions about themselves and about other people they know. Moreover, each individual is subject to vanity: if her interlocutor seems to value her highly, then she increases her opinion about this interlocutor. On the contrary she tends to decrease her opinion about those who seem to undervalue her. The combination of these dynamics with the hypothesis that the opinion propagation is more efficient when coming from highly valued individuals, leads to different patterns when varying the parameters. For instance, for some parameters the positive opinion links between individuals generate a small world network. In one of the patterns, absolute dominance of one agent alternates with a state of generalised distrust, where all agents have a very low opinion of all the others (including themselves). We provide some explanations of the mechanisms behind these emergent behaviors and finally propose a discussion about their interest. }, }
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F. Gargiulo, M. Lenormand, S. Huet, O. Baqueiro Espinosa
Commuting network models: Getting the essentials
JASSS-The Journal of Artificial Societies and Social Simulation 15 (2), 2012
abs web bib

Human mobility and, in particular, commuting patterns have a fundamental role in understanding socio-economic systems. Analysing and modelling the networks formed by commuters, for example, has become a crucial requirement in studying rural areas dynamics and to help decision-making. This paper presents a simple spatial interaction commuting model with only one parameter. The proposed algorithm considers each individual who wants to commute, starting from their residence to all the possible workplaces. The algorithm decides the location of the workplace following the classical rule inspired from the gravity law consisting of a compromise between the job offers and the distance to the job. The further away the job is, the more important the offer should be to be considered for the decision. Inversely, the quantity of offers is not important for the decision when these offers are close by. The presented model provides a simple, yet powerful approach to simulate realistic distributions of commuters for empirical studies with limited data availability. The paper also presents a comparative analysis of the structure of the commuting networks of the four European regions to which we apply our model. The model is calibrated and validated on these regions. The results from the analysis show that the model is very efficient in reproducing most of the statistical properties of the network given by the data sources.
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@article{PUB00035312, author = {Gargiulo, F. and Lenormand, M. and Huet, S. and Baqueiro Espinosa, O.}, title = {Commuting network models: Getting the essentials }, title = {Modèle de réseau de navettage: allons à l'essentiel}, journal = {JASSS-The Journal of Artificial Societies and Social Simulation}, volume = {15}, number = {2}, pages = {6}, url = {http://jasss.soc.surrey.ac.uk/15/2/6.html}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00035312}, year = {2012}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; LEIBNIZ INSTITUTE FOR AGRICULTURAL DEVELOPMENT IN CENTRAL AND EASTERN EUROPE IAMO DEU}, abstract = {Human mobility and, in particular, commuting patterns have a fundamental role in understanding socio-economic systems. Analysing and modelling the networks formed by commuters, for example, has become a crucial requirement in studying rural areas dynamics and to help decision-making. This paper presents a simple spatial interaction commuting model with only one parameter. The proposed algorithm considers each individual who wants to commute, starting from their residence to all the possible workplaces. The algorithm decides the location of the workplace following the classical rule inspired from the gravity law consisting of a compromise between the job offers and the distance to the job. The further away the job is, the more important the offer should be to be considered for the decision. Inversely, the quantity of offers is not important for the decision when these offers are close by. The presented model provides a simple, yet powerful approach to simulate realistic distributions of commuters for empirical studies with limited data availability. The paper also presents a comparative analysis of the structure of the commuting networks of the four European regions to which we apply our model. The model is calibrated and validated on these regions. The results from the analysis show that the model is very efficient in reproducing most of the statistical properties of the network given by the data sources. }, }
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F. Gargiulo, S. Huet
New discussions challenge the organization of societies
Advances in Complex Systems 15 (4), 2012
abs doi web bib

Can the discussions about new issues challenge the organization of a society? That is the question we tried to answer with a very simple model considering a society where individuals are organized into groups. An individual discuss its opinion on this new issue following the rule of the bounded confidence model implying that an individual influences and is influenced when it is sufficiently open-minded. One of the main ingredients of the model is the groups that both influence the behaviour of the individual and characterize the social network topology. Individuals choose the group membership according to their opinion. Starting from an initial homogeneous group size distribution, four different prototypical regimes can be reproduced by the model, depending on the individual open-mindedness: from a high heterogeneity condition, with one or two largely major groups, to an invariant situation of homogeneity. The heterogeneity is explained by the dynamics of individuals. In this paper we extend the studies of a previous work on the argument, deepening the analysis on the internal structure of the groups and on the dynamical process itself. To do this we analyze indicators related to the stability of the obtained virtual society. We found that the dynamics of groups is not stable when open-mindedness is small, even if the dynamics of opinions reaches equilibrium. On the other side, for larger values of the open-mindedness, both the opinion and the group dynamics stabilize. Thus our study shows that the introduction of a new topic of discussion in a society can strongly challenge group structures, both concerning their stability and their size. / Dans quelle mesure les discussions autour d'un nouveau problème de société la remettent-elle en cause ? C'est la question à laquelle nous tentons de répondre en partant d'un modèle simple de simulation considérant une société où les individus sont organisés en groupes. Un individu discute son opinion sur le nouveau sujet en utilisant la règle du modèle "bounded confidence" impliquant qu'il influence et est infuencé lorsqu'il a un esprit suffisamment ouvert. L'un des ingrédients principaux du modèle est le groupe qui influence tant le comportement de l'individu qu'il caractérise l'organisation sociale en réseau. Les individus se rattachent à un groupe en fonction de leur opinion. Partant d'une distribution uniforme de la taille des groupes, quatre régimes prototypiques peuvent être reproduit par le model selon le niveau d'ouverture d'esprit des individus : d'une taille de groupes très hétérogène avec un ou deux groupes très grands à un maintien de l'uniformité de la taille des groupes. L'hétérogénéïté est dû aux dynamiques individuelles. Ce papier poursuit les travaux déjà réalisés, analysant plus avant les structures des groupes et les dynamiques permettant d'atteindre ces structures. Les indicateurs de stabilité montrent que la dynamique des groupes est instables lorsque les esprits sont peu ouverts et ce même si les opinions se stabilisent. Pour des esprits esprits, tant les groupes que les opinions se stabilisent. Nous concluons que l'introduction d'un nouveau sujet de société dans les discussions peut remettre en cause la taille et la stabilité des groupes formant cette société.
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@article{PUB00035310, author = {Gargiulo, F. and Huet, S.}, title = {New discussions challenge the organization of societies}, title = {Les nouveaux sujets de discussions remettent en cause la société}, journal = {Advances in Complex Systems}, volume = {15}, number = {4}, pages = {17}, url = {http://cemadoc.irstea.fr/cemoa/PUB00035310}, doi = {http://dx.doi.org/10.1142/S0219525912500336}, year = {2012}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {Can the discussions about new issues challenge the organization of a society? That is the question we tried to answer with a very simple model considering a society where individuals are organized into groups. An individual discuss its opinion on this new issue following the rule of the bounded confidence model implying that an individual influences and is influenced when it is sufficiently open-minded. One of the main ingredients of the model is the groups that both influence the behaviour of the individual and characterize the social network topology. Individuals choose the group membership according to their opinion. Starting from an initial homogeneous group size distribution, four different prototypical regimes can be reproduced by the model, depending on the individual open-mindedness: from a high heterogeneity condition, with one or two largely major groups, to an invariant situation of homogeneity. The heterogeneity is explained by the dynamics of individuals. In this paper we extend the studies of a previous work on the argument, deepening the analysis on the internal structure of the groups and on the dynamical process itself. To do this we analyze indicators related to the stability of the obtained virtual society. We found that the dynamics of groups is not stable when open-mindedness is small, even if the dynamics of opinions reaches equilibrium. On the other side, for larger values of the open-mindedness, both the opinion and the group dynamics stabilize. Thus our study shows that the introduction of a new topic of discussion in a society can strongly challenge group structures, both concerning their stability and their size. / Dans quelle mesure les discussions autour d'un nouveau problème de société la remettent-elle en cause ? C'est la question à laquelle nous tentons de répondre en partant d'un modèle simple de simulation considérant une société où les individus sont organisés en groupes. Un individu discute son opinion sur le nouveau sujet en utilisant la règle du modèle "bounded confidence" impliquant qu'il influence et est infuencé lorsqu'il a un esprit suffisamment ouvert. L'un des ingrédients principaux du modèle est le groupe qui influence tant le comportement de l'individu qu'il caractérise l'organisation sociale en réseau. Les individus se rattachent à un groupe en fonction de leur opinion. Partant d'une distribution uniforme de la taille des groupes, quatre régimes prototypiques peuvent être reproduit par le model selon le niveau d'ouverture d'esprit des individus : d'une taille de groupes très hétérogène avec un ou deux groupes très grands à un maintien de l'uniformité de la taille des groupes. L'hétérogénéïté est dû aux dynamiques individuelles. Ce papier poursuit les travaux déjà réalisés, analysant plus avant les structures des groupes et les dynamiques permettant d'atteindre ces structures. Les indicateurs de stabilité montrent que la dynamique des groupes est instables lorsque les esprits sont peu ouverts et ce même si les opinions se stabilisent. Pour des esprits esprits, tant les groupes que les opinions se stabilisent. Nous concluons que l'introduction d'un nouveau sujet de société dans les discussions peut remettre en cause la taille et la stabilité des groupes formant cette société.}, }
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M. Lenormand, S. Huet, G. Deffuant
Deriving the number of jobs in proximity services from the number of inhabitants in french rural municipalities
PLoS One 7 (7), 2012
abs pdf doi web bib

We use a minimum requirement approach to derive the number of jobs in proximity services per inhabitant in French rural municipalities. We first classify the municipalities according to their time distance in minutes by car to the municipality where the inhabitants go the most frequently to get services (called MFM). For each set corresponding to a range of time distance to MFM, we perform a quantile regression estimating the minimum number of service jobs per inhabitant that we interpret as an estimation of the number of proximity jobs per inhabitant. We observe that the minimum number of service jobs per inhabitant is smaller in small municipalities. Moreover, for municipalities of similar sizes, when the distance to the MFM increases, the number of jobs of proximity services per inhabitant increases.
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@article{PUB00035599, author = {Lenormand, M. and Huet, S. and Deffuant, G.}, title = {Deriving the number of jobs in proximity services from the number of inhabitants in french rural municipalities}, title = {Déterminer le nombre d'emplois dans les services de proximité en fonction du nombre d'habitants dans les municipalités rurales françaises}, journal = {PLoS One}, volume = {7}, number = {7}, pages = {8}, pdf = {http://motive.cemagref.fr/_publication/PUB00035599.pdf}, url = {http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0040001}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00035599}, doi = {http://dx.doi.org/10.1371/journal.pone.0040001}, year = {2012}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {We use a minimum requirement approach to derive the number of jobs in proximity services per inhabitant in French rural municipalities. We first classify the municipalities according to their time distance in minutes by car to the municipality where the inhabitants go the most frequently to get services (called MFM). For each set corresponding to a range of time distance to MFM, we perform a quantile regression estimating the minimum number of service jobs per inhabitant that we interpret as an estimation of the number of proximity jobs per inhabitant. We observe that the minimum number of service jobs per inhabitant is smaller in small municipalities. Moreover, for municipalities of similar sizes, when the distance to the MFM increases, the number of jobs of proximity services per inhabitant increases.}, }
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M. Lenormand, S. Huet, F. Gargiulo, G. Deffuant
A universal model of commuting networks
PLoS One 7 (10), 2012
abs pdf doi web bib

We show that a recently proposed model generates accurate commuting networks on 80 case studies from different regions of the world (Europe and United-States) at different scales (e.g. municipalities, counties, regions). The model takes as input the number of commuters coming in and out of each geographic unit and generates the matrix of commuting flows between the units. The single parameter of the model follows a universal law that depends only on the scale of the geographic units. We show that our model significantly outperforms two other approaches proposing a universal commuting model (Balcan et al. (2009); Simini et al. (2012)), particularly when the geographic units are small (e.g. municipalities).
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@article{PUB00036161, author = {Lenormand, M. and Huet, S. and Gargiulo, F. and Deffuant, G.}, title = {A universal model of commuting networks}, title = {Un modèle universel de réseaux de navettage}, journal = {PLoS One}, volume = {7}, number = {10}, pages = {11}, pdf = {http://motive.cemagref.fr/_publication/PUB00036161.pdf}, url = {http://www.plosone.org}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00036161}, doi = {http://dx.doi.org/10.1371/journal.pone.0045985}, year = {2012}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; CNRS PARIS FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {We show that a recently proposed model generates accurate commuting networks on 80 case studies from different regions of the world (Europe and United-States) at different scales (e.g. municipalities, counties, regions). The model takes as input the number of commuters coming in and out of each geographic unit and generates the matrix of commuting flows between the units. The single parameter of the model follows a universal law that depends only on the scale of the geographic units. We show that our model significantly outperforms two other approaches proposing a universal commuting model (Balcan et al. (2009); Simini et al. (2012)), particularly when the geographic units are small (e.g. municipalities).}, }
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G. Deffuant, S. Huet
Collective increase of first impression bias
Complexity 15 (5), 2010
abs web bib

We propose a simple model of first impression bias (FIB), where agents tend to ignore features which contradict their initial view. We consider a population of agents which are all in contact with a media, communicating randomly chosen features of an object. In some cases, we observe on simulations that FIB is significantly more frequent when the agents interact with each other than when they are only in contact with the media. We design an analytical aggregated model of the global agent-based model behaviour which helps to explain the higher number of FIB due to the interactions.
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@article{PUB00026808, author = {Deffuant, G. and Huet, S.}, title = {Collective increase of first impression bias}, title = {Effets amplificateurs de l'interaction sur le biais de primauté}, journal = {Complexity}, volume = {15}, number = {5}, pages = {25-33}, url = {http://www3.interscience.wiley.com}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00026808}, year = {2010}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {We propose a simple model of first impression bias (FIB), where agents tend to ignore features which contradict their initial view. We consider a population of agents which are all in contact with a media, communicating randomly chosen features of an object. In some cases, we observe on simulations that FIB is significantly more frequent when the agents interact with each other than when they are only in contact with the media. We design an analytical aggregated model of the global agent-based model behaviour which helps to explain the higher number of FIB due to the interactions.}, }
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F. Gargiulo, S. Huet
Opinion dynamics in a group-based society
EPL 91 (58004), 2010
abs pdf doi bib

Many models have been proposed to analyze the evolution of opinion structure due to the interaction of individuals in their social environment. Such models analyze the spreading of ideas both in completely interacting backgrounds and on social networks, where each person has a finite set of interlocutors. In this paper we analyze the reciprocal feedback between the opinions of the individuals and the structure of the interpersonal relationships at the level of community structures. For this purpose we define a group based random network and we study how this structure co-evolves with opinion dynamics processes. We observe that the adaptive network structure affects the opinion dynamics process helping the consensus formation. The results also show interesting behaviors in regards to the size distribution of the groups and their correlation with opinion structure.
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@article{PUB00029366, author = {Gargiulo, F. and Huet, S.}, title = {Opinion dynamics in a group-based society}, title = {Dynamique d'opinion d'une société organisée en groupes}, journal = {EPL}, volume = {91}, number = {58004}, pages = {1-6}, pdf = {http://motive.cemagref.fr/_publication/PUB00029366.pdf}, doi = {http://dx.doi.org/10.1209/0295-5075/91/58004}, year = {2010}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {Many models have been proposed to analyze the evolution of opinion structure due to the interaction of individuals in their social environment. Such models analyze the spreading of ideas both in completely interacting backgrounds and on social networks, where each person has a finite set of interlocutors. In this paper we analyze the reciprocal feedback between the opinions of the individuals and the structure of the interpersonal relationships at the level of community structures. For this purpose we define a group based random network and we study how this structure co-evolves with opinion dynamics processes. We observe that the adaptive network structure affects the opinion dynamics process helping the consensus formation. The results also show interesting behaviors in regards to the size distribution of the groups and their correlation with opinion structure.}, }
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F. Gargiulo, S. Ternès, S. Huet, G. Deffuant
An iterative approach for generating statistically realistic populations of households
PLoS One 5 (1), 2010
abs pdf doi web bib

Many different simulation frameworks, in different topics, need to treat realistic datasets to initialize and calibrate the system. A precise reproduction of initial states is extremely important to obtain reliable forecast from the model. This paper proposes an algorithm to create an artificial population where individuals are described by their age, and are gathered in households respecting a variety of statistical constraints (distribution of household types, sizes, age of household head, difference of age between partners and among parents and children). Such a population is often the initial state of microsimulation or (agent) individual-based models. To get a realistic distribution of households is often very important, because this distribution has an impact on the demographic evolution. Usual techniques from microsimulation approach cross different sources of aggregated data for generating individuals. In our case the number of combinations of different households (types, sizes, age of participants) makes it computationally difficult to use directly such methods. Hence we developed a specific algorithm to make the problem more easily tractable. We generate the populations of two pilot municipalities in Auvergne region (France) to illustrate the approach. The generated populations show a good agreement with the available statistical datasets (not used for the generation) and are obtained in a reasonable computational time. / Dans beaucoup de domaines, la simulation nécessite le traitement de données réalistes pour initialiser et calibrer le système. Une reproduction précise de l'état initial contribue largement à l'obtention de prédictions fiables. Ce papier propose un algorithme de création d'une population artificielle composée d'individus décrits par leur âge. Ces individus sont membres de ménages qui respectent une variété de contraintes statistiques (distribution des types de ménages, différences d'âge dans les couples ou entre parents et enfants). Une telle population sert souvent d'état initial pour un modèle de microsimulation ou un modèle agent (ou individus-centré). La qualité de la distribution des ménages est importantes car cette distribution a un impact sur l'évolution démographique. Les techniques usuelles de microsimulation croisent différentes sources de données à des niveaux agrégés pour générer les individus. Dans notre cas, le nombre de combinaisons de différents ménages (types, taille, âge des membres) interdit une telle approche du fait de sa difficulté computationnelle. Nous proposons donc un algorithme permettant la génération relativement rapide et simple d'une telle population. Nous générons la population de deux municipalités Auvergnates pour illustrer l'approche. Les populations générées sont évaluées de bonne qualité par confrontation à des propriétés statistiques - non utilisées pour la génération - des communes qu'elles représentent. Elles sont obtenues en un temps raisonnable.
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@article{PUB00027953, author = {Gargiulo, F. and Ternès, S. and Huet, S. and Deffuant, G.}, title = {An iterative approach for generating statistically realistic populations of households}, title = {Une approche itérative pour la génération de populations de ménages réalistes du point de vue statistique}, journal = {PLoS One}, volume = {5}, number = {1}, pages = {9}, pdf = {http://motive.cemagref.fr/_publication/PUB00027953.pdf}, url = {http://www.plosone.org/article/info:doi/10.1371/journal.pone.0008828}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00027953}, doi = {http://dx.doi.org/10.1371/journal.pone.0008828 }, year = {2010}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {Many different simulation frameworks, in different topics, need to treat realistic datasets to initialize and calibrate the system. A precise reproduction of initial states is extremely important to obtain reliable forecast from the model. This paper proposes an algorithm to create an artificial population where individuals are described by their age, and are gathered in households respecting a variety of statistical constraints (distribution of household types, sizes, age of household head, difference of age between partners and among parents and children). Such a population is often the initial state of microsimulation or (agent) individual-based models. To get a realistic distribution of households is often very important, because this distribution has an impact on the demographic evolution. Usual techniques from microsimulation approach cross different sources of aggregated data for generating individuals. In our case the number of combinations of different households (types, sizes, age of participants) makes it computationally difficult to use directly such methods. Hence we developed a specific algorithm to make the problem more easily tractable. We generate the populations of two pilot municipalities in Auvergne region (France) to illustrate the approach. The generated populations show a good agreement with the available statistical datasets (not used for the generation) and are obtained in a reasonable computational time. / Dans beaucoup de domaines, la simulation nécessite le traitement de données réalistes pour initialiser et calibrer le système. Une reproduction précise de l'état initial contribue largement à l'obtention de prédictions fiables. Ce papier propose un algorithme de création d'une population artificielle composée d'individus décrits par leur âge. Ces individus sont membres de ménages qui respectent une variété de contraintes statistiques (distribution des types de ménages, différences d'âge dans les couples ou entre parents et enfants). Une telle population sert souvent d'état initial pour un modèle de microsimulation ou un modèle agent (ou individus-centré). La qualité de la distribution des ménages est importantes car cette distribution a un impact sur l'évolution démographique. Les techniques usuelles de microsimulation croisent différentes sources de données à des niveaux agrégés pour générer les individus. Dans notre cas, le nombre de combinaisons de différents ménages (types, taille, âge des membres) interdit une telle approche du fait de sa difficulté computationnelle. Nous proposons donc un algorithme permettant la génération relativement rapide et simple d'une telle population. Nous générons la population de deux municipalités Auvergnates pour illustrer l'approche. Les populations générées sont évaluées de bonne qualité par confrontation à des propriétés statistiques - non utilisées pour la génération - des communes qu'elles représentent. Elles sont obtenues en un temps raisonnable.}, }
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S. Huet, G. Deffuant
Openness leads to opinion stability and narrowness to volatility
Advances in Complex Systems 13 (3), 2010
abs pdf doi bib

We propose a new opinion dynamic model based on the experiments and results of Wood et al (1996). We consider pairs of individuals discussing on two attitudinal dimensions, and we suppose that one dimension is important, the other secondary. The dynamics are mainly ruled by the level of agreement on the main dimension. If two individuals are close on the main dimension, then they attract each other on the main and on the secondary dimensions, whatever their disagreement on the secondary dimension. If they are far from each other on the main dimension, then too much proximity on the secondary dimension is uncomfortable, and generates rejection on this dimension. The proximity is defined by comparing the opinion distance with a threshold called attraction threshold on the main dimension and rejection threshold on the secondary dimension. With such dynamics, a population with opinions initially uniformly drawn evolves to a set of clusters, inside which secondary opinions fluctuate more or less depending on threshold values. We observe that a low attraction threshold favours fluctuations on the secondary dimension, especially when the rejection threshold is high. The opinion evolutions of the model can be related to some stylised facts.
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@article{PUB00029104, author = {Huet, S. and Deffuant, G.}, title = {Openness leads to opinion stability and narrowness to volatility}, title = {L'ouverture d'esprit entraîne la stabilité des opinions tandis que le contraire entraîne leur volatilité}, journal = {Advances in Complex Systems}, volume = {13}, number = {3}, pages = {405-423}, pdf = {http://motive.cemagref.fr/_publication/PUB00029104.pdf}, doi = {http://dx.doi.org/10.1142/10.1142/S0219525910002633}, year = {2010}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {We propose a new opinion dynamic model based on the experiments and results of Wood et al (1996). We consider pairs of individuals discussing on two attitudinal dimensions, and we suppose that one dimension is important, the other secondary. The dynamics are mainly ruled by the level of agreement on the main dimension. If two individuals are close on the main dimension, then they attract each other on the main and on the secondary dimensions, whatever their disagreement on the secondary dimension. If they are far from each other on the main dimension, then too much proximity on the secondary dimension is uncomfortable, and generates rejection on this dimension. The proximity is defined by comparing the opinion distance with a threshold called attraction threshold on the main dimension and rejection threshold on the secondary dimension. With such dynamics, a population with opinions initially uniformly drawn evolves to a set of clusters, inside which secondary opinions fluctuate more or less depending on threshold values. We observe that a low attraction threshold favours fluctuations on the secondary dimension, especially when the rejection threshold is high. The opinion evolutions of the model can be related to some stylised facts.}, }
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I. Alvarez, S. Huet
Automatic diagnosis of engine of agricultural tractors: the BED experiment
Biosystems Engineering 100 (3), 2008
abs web bib

The test bed for evaluation and diagnosis (BED) is a simple device designed to perform a quick and automatic diagnosis of the engine of agricultural tractors. It compares the present performance of a tractor to the OECD test. Firstly, a test of the tractor is performed which measures the power take-off speed, the engine torque, the fuel consumption and several environmental variables. The performance curves of the tractor are then plotted against their official reference curves. A rule-based system (Scorpio) compares the present performance to the reference, analyses the differences and suggests which parts may be responsible for the lack of performance. A statistical validation of the expert system was carried out using a database of tests collected over 10 years. The output of the system was compared to the expert decision, which was available for more than a thousand records. This validation of the BED was confirmed by an in situ validation protocol conducted by a tractor repairer. The basic principles of the BED and the results of the validation studies are described / Le BED, (banc d'essai et de diagnostic) est un outil d'aide au diagnostic des moteurs de tracteurs. Il compare les performances actuelles d'un tracteur aux performances du test de référence OCDE. En premier lieu il permet d'effectuer un test du tracteur, en mesurant le couple à la prise de force, la consommation de carburant et des variables d'environnement en fonction de la vitesse à la prise de force. Les courbes de performance sont affichées en regard des courbes de référence. Un système à base de règle (Scorpio) compare les performances actuelles à la référence, analyse les différences et suggère les réglages à effectuer. Une validation statistique du système expert a été conduite sur une base de tests couvrant plus de 10 ans d'expérimentation, en comparant les propositions du système de diagnostic aux conclusion d'un expert pour plus de mille cas. Cette validation a été confirmée sur le terrain par un réparateur. Les principes de base du BED ainsi que les résultats des études de validation sont décrites dans cet article.
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@article{PUB00025620, author = {Alvarez, I. and Huet, S.}, title = {Automatic diagnosis of engine of agricultural tractors: the BED experiment}, title = {Diagnostic automatique des moteurs de tracteurs agricoles : l'expérience du BED}, journal = {Biosystems Engineering}, volume = {100}, number = {3}, pages = {362-369}, url = {http://dx.doi.org/10.1016/j.biosystemseng.2008.04.003}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00025620}, year = {2008}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {The test bed for evaluation and diagnosis (BED) is a simple device designed to perform a quick and automatic diagnosis of the engine of agricultural tractors. It compares the present performance of a tractor to the OECD test. Firstly, a test of the tractor is performed which measures the power take-off speed, the engine torque, the fuel consumption and several environmental variables. The performance curves of the tractor are then plotted against their official reference curves. A rule-based system (Scorpio) compares the present performance to the reference, analyses the differences and suggests which parts may be responsible for the lack of performance. A statistical validation of the expert system was carried out using a database of tests collected over 10 years. The output of the system was compared to the expert decision, which was available for more than a thousand records. This validation of the BED was confirmed by an in situ validation protocol conducted by a tractor repairer. The basic principles of the BED and the results of the validation studies are described / Le BED, (banc d'essai et de diagnostic) est un outil d'aide au diagnostic des moteurs de tracteurs. Il compare les performances actuelles d'un tracteur aux performances du test de référence OCDE. En premier lieu il permet d'effectuer un test du tracteur, en mesurant le couple à la prise de force, la consommation de carburant et des variables d'environnement en fonction de la vitesse à la prise de force. Les courbes de performance sont affichées en regard des courbes de référence. Un système à base de règle (Scorpio) compare les performances actuelles à la référence, analyse les différences et suggère les réglages à effectuer. Une validation statistique du système expert a été conduite sur une base de tests couvrant plus de 10 ans d'expérimentation, en comparant les propositions du système de diagnostic aux conclusion d'un expert pour plus de mille cas. Cette validation a été confirmée sur le terrain par un réparateur. Les principes de base du BED ainsi que les résultats des études de validation sont décrites dans cet article.}, }
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S. Huet, G. Deffuant, W. Jager
Rejection mechanism in 2D bounded confidence provides more conformity
Advances in Complex Systems 11 (4), 2008
abs pdf doi bib

This paper explores the dynamics of attitude change in 2 dimensions (2D) as a result of social interaction. We add a rejection mechanism into the 2D bounded confidence (BC) model proposed by Deffuant et al (2001). Individuals are characterised by twodimensional continuous attitudes, each associated with an uncertainty u, supposed constant in this first study. Individuals interact by random pairs. If their attitudes are closer than u on both dimensions, or further than u on both dimensions, or closer than u on one dimension and not further than u + delta u on the other dimension, then the rules of the BC model apply. But if their attitudes are closer than u on one dimension and further than u + delta u on the other dimension, then the individuals are in a dissonant state. They tend to solve it by shifting away their close attitudes. The model shows metastable clusters, which maintain themselves through opposite influences of competitor clusters. Our analysis and first experiments support the hypothesis that, for a large range of uncertainty values, the number of clusters grows linearly with the inverse of the uncertainty, whereas this growth is quadratic in the BC model.
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@article{PUB00024189, author = {Huet, S. and Deffuant, G. and Jager, W.}, title = {Rejection mechanism in 2D bounded confidence provides more conformity}, title = {Un mécanisme de rejet dans un modèle de confiance limitée 2D engendre davantage de conformité}, journal = {Advances in Complex Systems}, volume = {11}, number = {4}, pages = {529-549}, pdf = {http://motive.cemagref.fr/_publication/PUB00024189.pdf}, doi = {http://dx.doi.org/10.1142/S0219525908001799}, year = {2008}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; FACULTY OF ECONOMICS AND BUSINESS UNIVERSITY OF GRONINGEN NLD}, abstract = {This paper explores the dynamics of attitude change in 2 dimensions (2D) as a result of social interaction. We add a rejection mechanism into the 2D bounded confidence (BC) model proposed by Deffuant et al (2001). Individuals are characterised by twodimensional continuous attitudes, each associated with an uncertainty u, supposed constant in this first study. Individuals interact by random pairs. If their attitudes are closer than u on both dimensions, or further than u on both dimensions, or closer than u on one dimension and not further than u + delta u on the other dimension, then the rules of the BC model apply. But if their attitudes are closer than u on one dimension and further than u + delta u on the other dimension, then the individuals are in a dissonant state. They tend to solve it by shifting away their close attitudes. The model shows metastable clusters, which maintain themselves through opposite influences of competitor clusters. Our analysis and first experiments support the hypothesis that, for a large range of uncertainty values, the number of clusters grows linearly with the inverse of the uncertainty, whereas this growth is quadratic in the BC model.}, }
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S. Huet, G. Deffuant
Differential equation models derived from an individual-based model can help to understand emergent effects
JASSS-The Journal of Artificial Societies and Social Simulation 11 (2), 2008
abs web bib

We study a model of primacy effect on individual's attitude. Typically, when receiving a strong negative feature first, the individual keeps a negative attitude whatever the number of moderate positive features it receives afterwards. We consider a population of individuals, which receive the features from a media, and communicate with each other. We observe that interactions favour the primacy effect, compared with a population of isolated individuals. We derive a differential equation system ruling the evolution of probabilities that individuals retain different sets of features. The study of this aggregated model of the IBM shows that interaction can increase or decrease the number of individuals exhibiting a primacy effect. We verify on the IBM that the interactions can decrease the primacy effect in the conditions suggested by the study of the aggregated model. We finally discuss the interest of such a double-modelling approach (using a model of the individual based model) for this application.
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@article{PUB00024126, author = {Huet, S. and Deffuant, G.}, title = {Differential equation models derived from an individual-based model can help to understand emergent effects}, title = {Les modèles d'équations différentielles, dérivés d'un modèle individu centré, peuvent aider à la compréhension des effets émergents}, journal = {JASSS-The Journal of Artificial Societies and Social Simulation}, volume = {11}, number = {2}, pages = {16}, url = {http://jasss.soc.surrey.ac.uk/11/2/10.html}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00024126}, year = {2008}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {We study a model of primacy effect on individual's attitude. Typically, when receiving a strong negative feature first, the individual keeps a negative attitude whatever the number of moderate positive features it receives afterwards. We consider a population of individuals, which receive the features from a media, and communicate with each other. We observe that interactions favour the primacy effect, compared with a population of isolated individuals. We derive a differential equation system ruling the evolution of probabilities that individuals retain different sets of features. The study of this aggregated model of the IBM shows that interaction can increase or decrease the number of individuals exhibiting a primacy effect. We verify on the IBM that the interactions can decrease the primacy effect in the conditions suggested by the study of the aggregated model. We finally discuss the interest of such a double-modelling approach (using a model of the individual based model) for this application.}, }
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G. Deffuant, S. Huet
Propagation effects of filtering incongruent information
Journal of Business Research 60 (8), 2007
abs web bib

This report proposes for a simple individual-based model of information filtering, while focusing in particular on some of its implications for the attitude toward an object. The model assumes that a filter selects only important features, with a higher threshold of importance when the attitude toward the feature is incongruent with the global attitude toward the object. Individuals transmit only features that are congruent with their global attitude. This article considers two variants of the model. To both applies that different orders of feature reception can lead to different attitudes. For instance, a positive attitude toward an object can at a certain point become negative, even though the object is globally neutral (the sum of the feature attitudes is zero). The interactions among individuals can significantly increase the probability of such non-rational attitudes.
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@article{PUB00021835, author = {Deffuant, G. and Huet, S.}, title = {Propagation effects of filtering incongruent information}, title = {Effet de la propagation du filtrage d'informations incongruentes}, journal = {Journal of Business Research}, volume = {60}, number = {8}, pages = {816-825}, url = {http://cemadoc.irstea.fr/cemoa/PUB00021835}, year = {2007}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {This report proposes for a simple individual-based model of information filtering, while focusing in particular on some of its implications for the attitude toward an object. The model assumes that a filter selects only important features, with a higher threshold of importance when the attitude toward the feature is incongruent with the global attitude toward the object. Individuals transmit only features that are congruent with their global attitude. This article considers two variants of the model. To both applies that different orders of feature reception can lead to different attitudes. For instance, a positive attitude toward an object can at a certain point become negative, even though the object is globally neutral (the sum of the feature attitudes is zero). The interactions among individuals can significantly increase the probability of such non-rational attitudes.}, }
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S. Huet, M. Edwards, G. Deffuant
Taking into account the variations of neighbourhood sizes in the mean-field approximation of the threshold model on a random network
JASSS-The Journal of Artificial Societies and Social Simulation 10 (1), 2007
abs web bib

We compare the individual-based "threshold model" of innovation diffusion in the version which has been studied by Young (1998), with an aggregate model we derived from it. This model allows us to formalise and test hypotheses on the influence of individual characteristics upon global evolution. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure and a personal interest. Our study considers only the case where all have the same threshold. We present an aggregated model, which takes into account variations of the neighbourhood sizes, whereas previous work assumed this size fixed (Edwards et al. 2003a). The comparison between the aggregated models (the first one assuming a neighbourhood size and the second one, a variable one) points out an improvement of the approximation in most of the value of parameter space. This proves that the average degree of connectivity (first aggregated model) is not sufficient for characterising the evolution, and that the node degree variability has an impact on the diffusion dynamics. Remaining differences between both models give us some clues about the specific ability of individual-based model to maintain a minority behaviour which becomes a majority by an addition of stochastic effects.
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@article{PUB00021336, author = {Huet, S. and Edwards, M. and Deffuant, G.}, title = {Taking into account the variations of neighbourhood sizes in the mean-field approximation of the threshold model on a random network }, title = {Prendre en compte les variations de taille de voisinage social au sein d'une approximation par champ moyen d'un modèle à seuil sur un réseau aléatoire}, journal = {JASSS-The Journal of Artificial Societies and Social Simulation}, volume = {10}, number = {1}, pages = {15}, url = {http://jasss.soc.surrey.ac.uk/10/1/10.html}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00021336}, year = {2007}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {We compare the individual-based "threshold model" of innovation diffusion in the version which has been studied by Young (1998), with an aggregate model we derived from it. This model allows us to formalise and test hypotheses on the influence of individual characteristics upon global evolution. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure and a personal interest. Our study considers only the case where all have the same threshold. We present an aggregated model, which takes into account variations of the neighbourhood sizes, whereas previous work assumed this size fixed (Edwards et al. 2003a). The comparison between the aggregated models (the first one assuming a neighbourhood size and the second one, a variable one) points out an improvement of the approximation in most of the value of parameter space. This proves that the average degree of connectivity (first aggregated model) is not sufficient for characterising the evolution, and that the node degree variability has an impact on the diffusion dynamics. Remaining differences between both models give us some clues about the specific ability of individual-based model to maintain a minority behaviour which becomes a majority by an addition of stochastic effects.}, }
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G. Deffuant, S. Huet, F. Amblard
An individual-based model of innovation diffusion mixing social influence and rational anticipation
American Journal of Sociology 110 (4), 2005
abs web bib

We propose an individual-based model of innovation diffusion and explore its main dynamical properties. In the model, individuals give an a priori social value to the innovation, which evolves during their interactions with the Relative agreement influence model. This model offers the possibility of including a minority of extremists, with extreme and very certain opinions. Individuals who give a good social value to the innovation, tend to look for information which allows them to evaluate a more precise individual benefit of the adoption. They can get such information from their associates or from the media. If their social value is bad, neither they consider the information or transmit it. Individuals adopt the innovation if the overall evaluation including the social value and the individual benefit is good enough with a sufficient certainty. The main result of the model exploration is that innovations with high social values and bad individual benefit have more chances to succeed, than innovations with bad social value and high individual benefit. Moreover, in some cases, a minority of extremists can have a very important impact on the propagation, by polarizing the social value. / Nous proposons un modèle individu-centré de diffusion de l'innovation et explorons ses principales propriétés dynamiques. Dans notre modèle, les individus donnent une valeur sociale a priori à l'innovation. Cette valeur évolue durant les interactions entre les individus selon le modèle d'influence "Relative agreement". Ce modèle permet de prendre en compte les minorités dotées d'opinions extrêmes et certaines. Les individus pensant l'innovation bonne socialement recherchent l'information qui leur permettra d'évaluer précisément l'impact à titre personnel de l'adoption. Une telle information peut être disponible auprès d'un de leur collègue ou des medias. Lorsqu'ils pensent l'innovation mauvaise socialement, ils ne considèrent pas l'information et ne la transmettent pas. Les individus adoptent l'innovation si l'évaluation globale (incluant valeur sociale et impact à titre personnel) est suffisamment positive avec une certitude suffisante. Le résultat principal de l'exploration du modèle est que les innovations dotées d'une valeur sociale forte et d'un impact personnel mauvais ont davantage de chances d'être adoptées que les innovations dotées d'une mauvaise valeur sociale et d'un impact personnel bon. Par ailleurs, dans certains cas, une minorité d'extrémistes peut avoir un impact important sur la diffusion en diffusant à tous leurs opinions extrêmes sur la valeur sociale positive de l'innovation.
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@article{PUB00018516, author = {Deffuant, G. and Huet, S. and Amblard, F.}, title = {An individual-based model of innovation diffusion mixing social influence and rational anticipation}, title = {Un modèle individu-centré de diffusion de l'innovation mixant influence sociale et anticipation rationnelle}, journal = {American Journal of Sociology}, volume = {110}, number = {4}, pages = {1041-1069}, url = {http://cemadoc.irstea.fr/cemoa/PUB00018516}, year = {2005}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {We propose an individual-based model of innovation diffusion and explore its main dynamical properties. In the model, individuals give an a priori social value to the innovation, which evolves during their interactions with the Relative agreement influence model. This model offers the possibility of including a minority of extremists, with extreme and very certain opinions. Individuals who give a good social value to the innovation, tend to look for information which allows them to evaluate a more precise individual benefit of the adoption. They can get such information from their associates or from the media. If their social value is bad, neither they consider the information or transmit it. Individuals adopt the innovation if the overall evaluation including the social value and the individual benefit is good enough with a sufficient certainty. The main result of the model exploration is that innovations with high social values and bad individual benefit have more chances to succeed, than innovations with bad social value and high individual benefit. Moreover, in some cases, a minority of extremists can have a very important impact on the propagation, by polarizing the social value. / Nous proposons un modèle individu-centré de diffusion de l'innovation et explorons ses principales propriétés dynamiques. Dans notre modèle, les individus donnent une valeur sociale a priori à l'innovation. Cette valeur évolue durant les interactions entre les individus selon le modèle d'influence "Relative agreement". Ce modèle permet de prendre en compte les minorités dotées d'opinions extrêmes et certaines. Les individus pensant l'innovation bonne socialement recherchent l'information qui leur permettra d'évaluer précisément l'impact à titre personnel de l'adoption. Une telle information peut être disponible auprès d'un de leur collègue ou des medias. Lorsqu'ils pensent l'innovation mauvaise socialement, ils ne considèrent pas l'information et ne la transmettent pas. Les individus adoptent l'innovation si l'évaluation globale (incluant valeur sociale et impact à titre personnel) est suffisamment positive avec une certitude suffisante. Le résultat principal de l'exploration du modèle est que les innovations dotées d'une valeur sociale forte et d'un impact personnel mauvais ont davantage de chances d'être adoptées que les innovations dotées d'une mauvaise valeur sociale et d'un impact personnel bon. Par ailleurs, dans certains cas, une minorité d'extrémistes peut avoir un impact important sur la diffusion en diffusant à tous leurs opinions extrêmes sur la valeur sociale positive de l'innovation. }, }
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M. Edwards, N. Ferrand, F. Goreaud, S. Huet
The relevance of aggregating a water consumption model cannot be disconnected from the choice of information available on the resource
Simulation Modelling Practice and Theory 13 (4), 2005
abs doi web bib

Individual-based models, which permit a fine description of the dynamics of a population are costly in computation time and need many simulations for outlining global laws. Conversely aggregate models take less time for simulation and provide analytical understanding of the global evolution. Therefore they can sometimes profitably replace individual-based models. However, in many cases these models are linked to a model of environment which evolves over time. In this paper we show that the relevance of using an aggregate vs. an individual based model of water consumption highly depends on the information available on the resource. We use two versions of a consumption model (individual-based and aggregate), simulating a reversible diffusion process which depends on the information available on the resource. We compare the results of the two models for various kinds links between the resource and consumption models and corresponding to the information about the resource provided to the consumers. We propose and test different properties of this information which might lead to difference of the results. / Les modèles individus centrés, qui permettent de décrire finement la dynamique d'une population, sont coûteux en temps et nécessitent de nombreuses simulations pour comprendre leur comportement. Inversement, les modèles agrégés sont plus rapides à simuler, et donnent des interprétations analytiques des comportement globaux. C'est pourquoi ils peuvent parfois remplacer des modèles individus centrés. Cependant, dans de nombreux cas ces modèles doivent être couplés à des modèles de l'environnement, qui évolue au cours du temps. Dans cet article, nous montrons que, dans le cas des modèles de consommation d'eau, la pertinence d'utiliser un modèles agrégé plutôt qu'un modèle individus centré dépend fortement de l'information disponible sur la ressource. Nous utilisons deux versions d'un modèle de consommation d'eau (individus centré et agrégé), et simulons un processus réversible de diffusion des comportements qui dépend de l'information disponible sur la ressource. Nous comparons les résultats des deux modèles pour différents types de couplage entre la ressource et les modèles de consommation, qui correspondent à l'information sur la ressource donnée aux consommateurs. Nous testons comment différentes propriétés de ces informations peuvent entraîner des différences sur les résultats des simulations.
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@article{PUB00016842, author = {Edwards, M. and Ferrand, N. and Goreaud, F. and Huet, S.}, title = {The relevance of aggregating a water consumption model cannot be disconnected from the choice of information available on the resource}, title = {La pertinence de l'agrégation d'un modèle de consommation d'eau ne peut être évaluée indépendamment du choix de l'information disponible sur la ressource}, journal = {Simulation Modelling Practice and Theory}, volume = {13}, number = {4}, pages = {287-307}, url = {http://cemadoc.irstea.fr/cemoa/PUB00016842}, doi = {http://dx.doi.org/10.1016/j.simpat.2004.11.008}, year = {2005}, affiliation = {LIP6 PARIS ; CEMAGREF MONTPELLIER IRMO UMR G-EAU ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, number = {05/IRMO-PUB16842}, abstract = {Individual-based models, which permit a fine description of the dynamics of a population are costly in computation time and need many simulations for outlining global laws. Conversely aggregate models take less time for simulation and provide analytical understanding of the global evolution. Therefore they can sometimes profitably replace individual-based models. However, in many cases these models are linked to a model of environment which evolves over time. In this paper we show that the relevance of using an aggregate vs. an individual based model of water consumption highly depends on the information available on the resource. We use two versions of a consumption model (individual-based and aggregate), simulating a reversible diffusion process which depends on the information available on the resource. We compare the results of the two models for various kinds links between the resource and consumption models and corresponding to the information about the resource provided to the consumers. We propose and test different properties of this information which might lead to difference of the results. / Les modèles individus centrés, qui permettent de décrire finement la dynamique d'une population, sont coûteux en temps et nécessitent de nombreuses simulations pour comprendre leur comportement. Inversement, les modèles agrégés sont plus rapides à simuler, et donnent des interprétations analytiques des comportement globaux. C'est pourquoi ils peuvent parfois remplacer des modèles individus centrés. Cependant, dans de nombreux cas ces modèles doivent être couplés à des modèles de l'environnement, qui évolue au cours du temps. Dans cet article, nous montrons que, dans le cas des modèles de consommation d'eau, la pertinence d'utiliser un modèles agrégé plutôt qu'un modèle individus centré dépend fortement de l'information disponible sur la ressource. Nous utilisons deux versions d'un modèle de consommation d'eau (individus centré et agrégé), et simulons un processus réversible de diffusion des comportements qui dépend de l'information disponible sur la ressource. Nous comparons les résultats des deux modèles pour différents types de couplage entre la ressource et les modèles de consommation, qui correspondent à l'information sur la ressource donnée aux consommateurs. Nous testons comment différentes propriétés de ces informations peuvent entraîner des différences sur les résultats des simulations.}, }
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M. Edwards, S. Huet, F. Goreaud, G. Deffuant
Comparing an individual-based model of behaviour diffusion with its mean field aggregate approximation.
JASSS-The Journal of Artificial Societies and Social Simulation 6 (4), 2003
abs web bib

In this paper we compare a version of the individual-based 'threshold model' of innovation diffusion with an aggregate deterministic model that we constructed from it. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure (the number of neighbours adopting the behaviour) and a personal interest or resistance to change (the threshold). The aggregate model makes approximations in order to estimate the evolution of groups of individuals with the same number of neighbours of similar behaviour. We compare both models at different points of the parameter space. We find that the aggregate model gives a good approximation of the individual in some cases; however in other cases the behaviour of the aggregate approximation differs. Using theoretical interpretation of this difference based on a study of the attractors of the aggregate model, we hypothesise that the two models have the same behaviour when the aggregate model has only one attractor and that differences can occur when it has two. / Nous comparons un modèle individu-centré à seuil de diffusion de l'innovation (Valente 1995) dans la version étudiée par P. Young, et un modèle agrégé déterministe que nous avons construit en cohérence. Le modèle classique de diffusion de l'innovation à seuil suppose qu'un individu adopte un comportement suivant un compromis entre la pression sociale (le nombre de ses voisins ayant adopté ce comportement) et un intérêt personnel de résistance au changement (le seuil). Le modèle agrégé fait appel à des approximations pour estimer l'évolution de groupes d'individus ayant le même nombre de voisins suivant un certain comportement. Nous comparons ces deux modèles en différents points de l'espace des paramètres. Nous trouvons que le modèle agrégé approxime bien le modèle individu-centré dans certains cas ; toutefois, il s'avère également parfois que le comportement du modèle agrégé diffère. En nous appuyant sur une interprétation théorique de cette différence, fondée sur une étude des attracteurs du modèle agrégé, nous proposons l'hypothèse que les deux modèles suivent le même comportement lorsque le modèle agrégé n'a qu'un seul attracteur, et que des différences peuvent apparaître quand il en a deux.
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@article{PUB00018793, author = {Edwards, M. and Huet, S. and Goreaud, F. and Deffuant, G.}, title = {Comparing an individual-based model of behaviour diffusion with its mean field aggregate approximation.}, title = {Comparaison d'un modèle individu-centré de diffusion de l'innovation avec son approximation par champ moyen}, journal = {JASSS-The Journal of Artificial Societies and Social Simulation}, volume = {6}, number = {4}, url = {http://jasss.soc.surrey.ac.uk/6/4/9.html}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00018793}, year = {2003}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {In this paper we compare a version of the individual-based 'threshold model' of innovation diffusion with an aggregate deterministic model that we constructed from it. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure (the number of neighbours adopting the behaviour) and a personal interest or resistance to change (the threshold). The aggregate model makes approximations in order to estimate the evolution of groups of individuals with the same number of neighbours of similar behaviour. We compare both models at different points of the parameter space. We find that the aggregate model gives a good approximation of the individual in some cases; however in other cases the behaviour of the aggregate approximation differs. Using theoretical interpretation of this difference based on a study of the attractors of the aggregate model, we hypothesise that the two models have the same behaviour when the aggregate model has only one attractor and that differences can occur when it has two. / Nous comparons un modèle individu-centré à seuil de diffusion de l'innovation (Valente 1995) dans la version étudiée par P. Young, et un modèle agrégé déterministe que nous avons construit en cohérence. Le modèle classique de diffusion de l'innovation à seuil suppose qu'un individu adopte un comportement suivant un compromis entre la pression sociale (le nombre de ses voisins ayant adopté ce comportement) et un intérêt personnel de résistance au changement (le seuil). Le modèle agrégé fait appel à des approximations pour estimer l'évolution de groupes d'individus ayant le même nombre de voisins suivant un certain comportement. Nous comparons ces deux modèles en différents points de l'espace des paramètres. Nous trouvons que le modèle agrégé approxime bien le modèle individu-centré dans certains cas ; toutefois, il s'avère également parfois que le comportement du modèle agrégé diffère. En nous appuyant sur une interprétation théorique de cette différence, fondée sur une étude des attracteurs du modèle agrégé, nous proposons l'hypothèse que les deux modèles suivent le même comportement lorsque le modèle agrégé n'a qu'un seul attracteur, et que des différences peuvent apparaître quand il en a deux.}, }
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Book Chapters (6)

S. Huet, N. Dumoulin, G. Deffuant
A calibration to properly design a model integrating residential mobility and migration in rural area
Advances in Social Simulation 2015, Advances in Intelligent Systems and Computing 528 (p. 163-179), Springer, 2017
abs web bib

We propose a hybrid microsimulation and agent-based model of mobility integrating migration and residential mobility. We tested it on the evolution of the population of the Cantal, a French “département” with 150,000 inhabitants. We calibrated it using various data sources from 1990 to 2006, and tested its predictions on other data of the same period and on the period 2007-2012. The spatial heterogeneity of the evolution is well reproduced and the model makes surprisingly correct predictions despite numerous simplifying assumptions. From this calibration we learnt more about how to model residential mobility and migration considering an agent-based model approach.
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@book{PUB00054555, author = {Huet, S. and Dumoulin, N. and Deffuant, G.}, author = {Jager, W. and Verbrugge, R. and Flache, A. and De Roo, G. and Hoogduin, L. and Hemelrijkn C.}, title = {A calibration to properly design a model integrating residential mobility and migration in rural area}, title = {Une calibration pour une modélisation pertinente de la mobilité résidentielle et de la migration en zone rurale}, bookTitle = {Advances in Social Simulation 2015, Advances in Intelligent Systems and Computing 528}, publisher = {Springer}, pages = {163-179}, url = {http://cemadoc.irstea.fr/cemoa/PUB00054555}, year = {2017}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {We propose a hybrid microsimulation and agent-based model of mobility integrating migration and residential mobility. We tested it on the evolution of the population of the Cantal, a French “département” with 150,000 inhabitants. We calibrated it using various data sources from 1990 to 2006, and tested its predictions on other data of the same period and on the period 2007-2012. The spatial heterogeneity of the evolution is well reproduced and the model makes surprisingly correct predictions despite numerous simplifying assumptions. From this calibration we learnt more about how to model residential mobility and migration considering an agent-based model approach.}, }
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S. Huet, G. Deffuant
The Leviathan model without gossips and vanity: The richness of influence based on perceived hierarchy
Advances in Social Simulation 2015, Advances in Intelligent Systems and Computing 528 (p. 149-162), Springer, 2017
abs web bib

This paper studies a model of agents having an opinion about each other agent and about themselves. During dyadic meetings, the agents change their opinion about themselves and about their interlocutor in the direction of a noisy perception of the opinions of their interlocutor. Moreover highly valued agents are more influential. This model produces several patterns depending on the parameter values. In particular, in some cases several highly influential agents (called leaders) emerge and sometimes the leaders have a low opinion of each other.
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@book{PUB00054554, author = {Huet, S. and Deffuant, G.}, author = {Jager, W. and Verbrugge, R. and Flache, A. and De Roo, G. and Hoogduin, L. and Hemelrijk, C.}, title = {The Leviathan model without gossips and vanity: The richness of influence based on perceived hierarchy}, title = {Le modèle Leviathan sans commérage ou vanité : la richesse d'une influence basée sur la hiérarchie perçue}, bookTitle = {Advances in Social Simulation 2015, Advances in Intelligent Systems and Computing 528}, publisher = {Springer}, pages = {149-162}, url = {http://cemadoc.irstea.fr/cemoa/PUB00054554}, year = {2017}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {This paper studies a model of agents having an opinion about each other agent and about themselves. During dyadic meetings, the agents change their opinion about themselves and about their interlocutor in the direction of a noisy perception of the opinions of their interlocutor. Moreover highly valued agents are more influential. This model produces several patterns depending on the parameter values. In particular, in some cases several highly influential agents (called leaders) emerge and sometimes the leaders have a low opinion of each other.}, }
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S. Huet, M. Lenormand, G. Deffuant, F. Gargiulo
Parameterisation of individual working dynamics
Empirical Agent-Based Modelling – Challenges and Solutions. Volume 1, The Characterisation and Parameterisation of Empirical Agent-Based Models (p. 133-169), Springer, New York, USA, 2014
abs doi web bib

During the PRIMA European project, we conceived a conceptual model dedicated to the study of the evolution of the European Rural Areas in terms of demography and occupation of their populations. This is a hybrid agent-microsimulation model considering inhabitants as the basic elements composing in households. On the other hand, municipalities are the basic spatial element and the providers for employment and housings. This chapter presents the main objects and their relationships are identified as a first generic way to parameterize the dynamics of such a conceptual model for an implementation of a European region. This chapter explains how dynamics can be parameterised from data for an implementation for a French region. It focusses on the dynamics of work statuses and professions which can be derived from the European Labour Force Survey (LFS). The individual is considered from her entering on the labour market until the moment she decides to retire. Meanwhile, she can be fired, searching for a job when she is unemployed or already employed but also deciding becoming inactive for a while. Jobs are defined by a profession and an activity sector. The job offer is located at the municipality level and can correspond to the searched profession of an individual having a municipality of residence. The French implementation is described starting from the employment survey in France, which is the French declination of the LFS.
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@book{PUB00039099, author = {Huet, S. and Lenormand, M. and Deffuant, G. and Gargiulo, F.}, author = {Smajgl, A. and Barreteau, O.}, title = {Parameterisation of individual working dynamics}, title = {Paramétrisation de la dynamique individuelle relative au travail}, bookTitle = {Empirical Agent-Based Modelling – Challenges and Solutions. Volume 1, The Characterisation and Parameterisation of Empirical Agent-Based Models}, address = {New York, USA}, publisher = {Springer}, pages = {133-169}, url = {http://cemadoc.irstea.fr/cemoa/PUB00039099}, doi = {http://dx.doi.org/10.1007/978-1-4614-6134-0_8}, year = {2014}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR TSCF FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, ISBNISSN = {ISBN 978-1-4614-6133-3}, abstract = {During the PRIMA European project, we conceived a conceptual model dedicated to the study of the evolution of the European Rural Areas in terms of demography and occupation of their populations. This is a hybrid agent-microsimulation model considering inhabitants as the basic elements composing in households. On the other hand, municipalities are the basic spatial element and the providers for employment and housings. This chapter presents the main objects and their relationships are identified as a first generic way to parameterize the dynamics of such a conceptual model for an implementation of a European region. This chapter explains how dynamics can be parameterised from data for an implementation for a French region. It focusses on the dynamics of work statuses and professions which can be derived from the European Labour Force Survey (LFS). The individual is considered from her entering on the labour market until the moment she decides to retire. Meanwhile, she can be fired, searching for a job when she is unemployed or already employed but also deciding becoming inactive for a while. Jobs are defined by a profession and an activity sector. The job offer is located at the municipality level and can correspond to the searched profession of an individual having a municipality of residence. The French implementation is described starting from the employment survey in France, which is the French declination of the LFS.}, }
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G. Deffuant, S. Huet, T. Carletti
La complexité d’un modèle simplifié d’interactions sociales : le modèle Leviathan
Modéliser & simuler. Epistémologie et pratiques de la modélisation et de la simulation (p. 749-778), Editions Matériologiques, Paris, 2013
abs web bib

Nous décrivons un modèle de dynamique d’opinions dans lequel les agents se rencontrent deux à deux de manière aléatoire et font évoluer les opinions qu’ils ont les uns des autres par des mécanismes de vanité et de propagation. Les simulations révèlent une grande richesse de comportements du modèle lorsque les paramètres varient. Nous avons identifié cinq types de dynamiques : égalité, élite, crise, hiérarchie, domination. Nous étudions l’apparition de ces types de dynamiques lorsque les paramètres du modèle varient et nous en proposons des explications théoriques partielles. Enfin, nous discutons l’intérêt de cette approche dans une perspective plus large des sciences sociales.
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@book{PUB00038246, author = {Deffuant, G. and Huet, S. and Carletti, T.}, author = {Varenne, F. and Silberstein, M.}, title = {La complexité d’un modèle simplifié d’interactions sociales : le modèle Leviathan}, title = {The complexity of a simplified model of social interactions: the Leviathan model}, bookTitle = {Modéliser & simuler. Epistémologie et pratiques de la modélisation et de la simulation}, series = {Sciences & Philosophie}, address = {Paris}, publisher = {Editions Matériologiques}, pages = {749-778}, url = {http://www.materiologiques.com/Modeliser-simuler-Epistemologies}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00038246}, year = {2013}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; UNIVERSITE DE NAMUR BEL}, ISBNISSN = {ISBN : 978-2-919694-19-8}, abstract = {Nous décrivons un modèle de dynamique d’opinions dans lequel les agents se rencontrent deux à deux de manière aléatoire et font évoluer les opinions qu’ils ont les uns des autres par des mécanismes de vanité et de propagation. Les simulations révèlent une grande richesse de comportements du modèle lorsque les paramètres varient. Nous avons identifié cinq types de dynamiques : égalité, élite, crise, hiérarchie, domination. Nous étudions l’apparition de ces types de dynamiques lorsque les paramètres du modèle varient et nous en proposons des explications théoriques partielles. Enfin, nous discutons l’intérêt de cette approche dans une perspective plus large des sciences sociales. }, }
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G. Deffuant, S. Huet, S. Skerratt
An agent based model of agri-environmental measure diffusion: What for ?
Agent based modelling in natural resource management (p. 55-73), INSISOC, Valladolid, ESP, 2008
abs web bib

This paper focuses on the agent based model of the diffusion of agri-environmental measures developed in the IMAGES European project (1997 2001). We describe the main stages of this model elaboration, showing that it synthesises different modelling points of view. We then illustrate its representative power using a case study in Scotland. Finally, we point out some difficulties in the practical use of such models, particularly as decision supports for policy makers. We advocate a more careful study of the model through systematic experiments, and for the further development of a model of its aggregated dynamics, in order to give more reliable information to policy makers.
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@book{PUB00024125, author = {Deffuant, G. and Huet, S. and Skerratt, S.}, author = {Lopez Paredes, A. and Hernandez Iglesias, C.}, title = {An agent based model of agri-environmental measure diffusion: What for ?}, title = {Un modèle agent de diffusion de mesures agri-environnementales: pourquoi ?}, bookTitle = {Agent based modelling in natural resource management}, address = {Valladolid, ESP}, publisher = {INSISOC}, pages = {55-73}, url = {http://cemadoc.irstea.fr/cemoa/PUB00024125}, year = {2008}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; SCOTTISH AGRICULTURAL COLLEGE EDINBURGH GBR}, ISBNISSN = {ISBN 978-84-205-4560-8}, abstract = {This paper focuses on the agent based model of the diffusion of agri-environmental measures developed in the IMAGES European project (1997 2001). We describe the main stages of this model elaboration, showing that it synthesises different modelling points of view. We then illustrate its representative power using a case study in Scotland. Finally, we point out some difficulties in the practical use of such models, particularly as decision supports for policy makers. We advocate a more careful study of the model through systematic experiments, and for the further development of a model of its aggregated dynamics, in order to give more reliable information to policy makers. }, }
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G. Deffuant, F. Amblard, S. Huet, S. Bernard, N. Ferrand, J.P. Bousset, G. Amon, J. Henriot, N. Gilbert, E. Chattoe, G. Weisbuch
Simulation de l'évolution des conversions à l'agriculture biologique dans le département de l'Allier entre 1994 et 1999 par un modèle multi-agents department
Complexity and Ecosystem Management: the Theory and Practice of Multi-agent Systems (p. 19), Edward Elgar Publishers, Cheltenham, UK/Northampton, MA, USA, 2002
abs web bib

We present a model allowing to simulate the evolution of the conversions to organic farming in Allier department from 1994 to 1999. The model is made up of investigations carried out in the field as well as various statistical data. It is based on a statistically valid reconstruction of farmers of the department and their situation per district. The social networks of farmers (made up with other farmers and institutional actors) are considered in the model. The conversion decision is modelled like the result of a process including several stages. Social interactions and economic calculations closely mixed in this process. The aim in the long term is to provide prospective trends on the future evolutions of conversions, according to assumptions on the economic and political context. / Nous présentons un modèle permettant de simuler l'évolution des conversions à l'agriculture biologique dans le département de l'Allier entre 1994 et 1999. Le modèle se nourrit d'enquêtes réalisées sur le terrain ainsi que de données statistiques diverses. Il se fonde sur une reconstitution valide statistiquement de la population d'agriculteurs du département et leur localisation par commune. Les réseaux sociaux des agriculteurs (constitués d'autres agriculteurs et d'acteurs institutionnels) sont considérés dans le modèle. La décision de conversion est modélisée comme le résultat d'un processus comprenant plusieurs étapes. Interactions sociales et calculs économiques se mêlent étroitement dans ce processus. L'objectif du modèle à terme est de fournir des tendances prospectives sur les évolutions futures des conversions, en fonction d'hypothèses sur l'évolution du contexte économique et politique.
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@book{PUB00013158, author = {Deffuant, G. and Amblard, F. and Huet, S. and Bernard, S. and Ferrand, N. and Bousset, J.P. and Amon, G. and Henriot, J. and Gilbert, N. and Chattoe, E. and Weisbuch, G.}, author = {Janssen, M.A.}, title = {Simulation de l'évolution des conversions à l'agriculture biologique dans le département de l'Allier entre 1994 et 1999 par un modèle multi-agents department}, title = {Agent-based simulation of organic farming conversion in Allier }, bookTitle = {Complexity and Ecosystem Management: the Theory and Practice of Multi-agent Systems}, address = {Cheltenham, UK/Northampton, MA, USA}, publisher = {Edward Elgar Publishers}, pages = {19}, url = {http://cemadoc.irstea.fr/cemoa/PUB00013158}, year = {2002}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND DFCF ; CEMAGREF CLERMONT FERRAND DFCF ; CEMAGREF CLERMONT FERRAND DFCF ; UNIVERSITY OF SURREY GUILDBORD GBR ; UNIVERSITY OXFORD GBR ; ENS PARIS FRA}, number = {02/0948 ; K LI02 8}, abstract = {We present a model allowing to simulate the evolution of the conversions to organic farming in Allier department from 1994 to 1999. The model is made up of investigations carried out in the field as well as various statistical data. It is based on a statistically valid reconstruction of farmers of the department and their situation per district. The social networks of farmers (made up with other farmers and institutional actors) are considered in the model. The conversion decision is modelled like the result of a process including several stages. Social interactions and economic calculations closely mixed in this process. The aim in the long term is to provide prospective trends on the future evolutions of conversions, according to assumptions on the economic and political context. / Nous présentons un modèle permettant de simuler l'évolution des conversions à l'agriculture biologique dans le département de l'Allier entre 1994 et 1999. Le modèle se nourrit d'enquêtes réalisées sur le terrain ainsi que de données statistiques diverses. Il se fonde sur une reconstitution valide statistiquement de la population d'agriculteurs du département et leur localisation par commune. Les réseaux sociaux des agriculteurs (constitués d'autres agriculteurs et d'acteurs institutionnels) sont considérés dans le modèle. La décision de conversion est modélisée comme le résultat d'un processus comprenant plusieurs étapes. Interactions sociales et calculs économiques se mêlent étroitement dans ce processus. L'objectif du modèle à terme est de fournir des tendances prospectives sur les évolutions futures des conversions, en fonction d'hypothèses sur l'évolution du contexte économique et politique.}, }
close

In Proceedings (35)

S. Huet
When ego-involved and non ego-involved agents lead to polarization despite a large consensus
Social Simulation Conference 2016, 19/09/2016-23/09/2016, Rome, ITA , 2016
abs web bib

Huet & Deffuant showed polarisation on minor issues can be reproduced by a dynamics inspired from laboratory experiments considering a population of self-involved agents on a main issue. This paper studies the impact of a mixed population of self-involved and not self-involved agents. The dynamics of self-involved agents is based on Huet & Deffuant meaning agents are attracted on every issues if they are close on to the main issue but reject their peer’s opinion if they are only close onto secondary issue. The dynamics of non self-involved agents is a simple 2D bounded confidence model. In this paper, we focus on the level of polarisation of agents when they are majorly gathered into one cluster. We observe the emergence of various types of “extreme minor clusters”. They can lead the population to a polarisation on minor issues, but also on fundamental ones. A very long transitory state of in group polarisation on secondary issues has been also exhibited. Some of these states are specific to mixed populations.
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@inproceedings{PUB00052594, author = {Huet, S.}, title = {When ego-involved and non ego-involved agents lead to polarization despite a large consensus}, title = {Lorsque la co-présence d'individus engagés et non engagés mène à la polarisation de tous malgré un large consensus modéré initial}, bookTitle = {Social Simulation Conference 2016, 19/09/2016-23/09/2016, Rome, ITA}, url = {http://cemadoc.irstea.fr/cemoa/PUB00052594}, year = {2016}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {Huet & Deffuant showed polarisation on minor issues can be reproduced by a dynamics inspired from laboratory experiments considering a population of self-involved agents on a main issue. This paper studies the impact of a mixed population of self-involved and not self-involved agents. The dynamics of self-involved agents is based on Huet & Deffuant meaning agents are attracted on every issues if they are close on to the main issue but reject their peer’s opinion if they are only close onto secondary issue. The dynamics of non self-involved agents is a simple 2D bounded confidence model. In this paper, we focus on the level of polarisation of agents when they are majorly gathered into one cluster. We observe the emergence of various types of “extreme minor clusters”. They can lead the population to a polarisation on minor issues, but also on fundamental ones. A very long transitory state of in group polarisation on secondary issues has been also exhibited. Some of these states are specific to mixed populations.}, }
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S. Huet, N. Dumoulin, G. Deffuant
A calibration to properly design a model integrating residential mobility and migration in a rural area
11th Conference of the European Social Simulation Association: Social Simulation Conference, 14/09/2015-18/09/2015, Groningen, NLD , 2015
abs web bib

We propose a hybrid microsimulation and agent-based model of mobility integrating migration and residential mobility. We tested it on the evolution of the population of the Cantal, a French “département” with 150,000 inhabitants. We calibrated it using various data sources from 1990 to 2006, and tested its predictions on other data of the same period and on the period 2007-2012. The spatial heterogeneity of the evolution is well reproduced and the model makes surprisingly correct predictions despite numerous simplifying assumptions. From this calibration we learnt more about how to model residential mobility and migration considering an agent-based model approach.
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@inproceedings{PUB00046433, author = {Huet, S. and Dumoulin, N. and Deffuant, G.}, title = {A calibration to properly design a model integrating residential mobility and migration in a rural area}, title = {Une calibration pour la conception pertinente d'un modèle intégrant mobilité résidentielle et migration dans l'espace rural}, bookTitle = {11th Conference of the European Social Simulation Association: Social Simulation Conference, 14/09/2015-18/09/2015, Groningen, NLD}, url = {http://cemadoc.irstea.fr/cemoa/PUB00046433}, year = {2015}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {We propose a hybrid microsimulation and agent-based model of mobility integrating migration and residential mobility. We tested it on the evolution of the population of the Cantal, a French “département” with 150,000 inhabitants. We calibrated it using various data sources from 1990 to 2006, and tested its predictions on other data of the same period and on the period 2007-2012. The spatial heterogeneity of the evolution is well reproduced and the model makes surprisingly correct predictions despite numerous simplifying assumptions. From this calibration we learnt more about how to model residential mobility and migration considering an agent-based model approach.}, }
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S. Huet, G. Deffuant
The Leviathan model without gossips and vanity: the richness of influence based on perceived hierarchy
Social Simulation Conference 2015, 14/09/2015-18/09/2015, Groningen, NLD (p. 13), 2015
abs pdf bib

This paper studies a simplified version of the Leviathan model, without gossip and vanity processes. During dyadic meetings, the agents change their opinion about themselves and about their interlocutor. Speakers highly valued by their listeners are more influential. Only due to the asymmetry of the influence function, the model produces several patterns depending on the parameter values, some of which not yet identified in the first Leviathan model study. In particular, in some cases the leaders have a high opinion of other leaders whereas in other cases they have a low one
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@inproceedings{PUB00045203, author = {Huet, S. and Deffuant, G.}, title = {The Leviathan model without gossips and vanity: the richness of influence based on perceived hierarchy}, title = {Le modèle Leviathan sans commérage ni vanité : la richesse d'une dynamique d'influence basé sur la hiérarchie perçue}, bookTitle = {Social Simulation Conference 2015, 14/09/2015-18/09/2015, Groningen, NLD}, pages = {13}, pdf = {http://motive.cemagref.fr/_publication/PUB00045203.pdf}, year = {2015}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {This paper studies a simplified version of the Leviathan model, without gossip and vanity processes. During dyadic meetings, the agents change their opinion about themselves and about their interlocutor. Speakers highly valued by their listeners are more influential. Only due to the asymmetry of the influence function, the model produces several patterns depending on the parameter values, some of which not yet identified in the first Leviathan model study. In particular, in some cases the leaders have a high opinion of other leaders whereas in other cases they have a low one}, }
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C. Druilhe, S. Huet, A. Trémier, G. Debenest
Temporal and spatial distribution of organic waste physical properties along composting process
9th Conference on Organic Resources and Biological Treatment, ORBIT 2014, 26/06/2014-28/06/2014, Gödöllo, HUN (p. 14), 2014
abs web bib

As an aerobic biological treatment, the composting process is influenced by the physical properties of organic waste. On one hand, material settlement, air permeability and free air space affect the aeration efficiency and the composting performance. On the other hand, the organic matter biodegradation during the process leads to a variation of material physical properties. The aim of this study was to investigate the time variation and the spatial distribution of the physical properties of a sludge and bulking agent mixture during its composting treatment. Composting was carried out in 300L pilot-scale reactors with forced aeration. In order to follow the spatial distribution in each reactor, the material was divided in three layers. Reactors were respectively stopped after 1.5, 3, 7, 14 and 31 composting days, and each material layer was characterized for moisture content, bulk density, free air space (FAS) and air permeability (K). The results showed that the changes in material properties were different according to the considered layer. The deepest layer, impacted by the air inlet in the reactor, had the highest decrease of moisture content and bulk density, a steady K and the highest FAS increase, whereas the surface layer, impacted by a condensate dropout, showed a slight increase of moisture content, steady density and FAS, and a very strong increase of K. Then, a physical structural reorganization of material occurred during the process. In the future, the obtained results could help to improve composting models, taking into account the temporal and spatial distribution of physical properties in the porous media.
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@inproceedings{PUB00052663, author = {Druilhe, C. and Huet, S. and Trémier, A. and Debenest, G.}, title = {Temporal and spatial distribution of organic waste physical properties along composting process}, bookTitle = {9th Conference on Organic Resources and Biological Treatment, ORBIT 2014, 26/06/2014-28/06/2014, Gödöllo, HUN}, pages = {14}, url = {http://cemadoc.irstea.fr/cemoa/PUB00052663}, year = {2014}, affiliation = {IRSTEA RENNES UR OPAALE FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA RENNES UR OPAALE FRA ; IMFT TOULOUSE FRA}, abstract = {As an aerobic biological treatment, the composting process is influenced by the physical properties of organic waste. On one hand, material settlement, air permeability and free air space affect the aeration efficiency and the composting performance. On the other hand, the organic matter biodegradation during the process leads to a variation of material physical properties. The aim of this study was to investigate the time variation and the spatial distribution of the physical properties of a sludge and bulking agent mixture during its composting treatment. Composting was carried out in 300L pilot-scale reactors with forced aeration. In order to follow the spatial distribution in each reactor, the material was divided in three layers. Reactors were respectively stopped after 1.5, 3, 7, 14 and 31 composting days, and each material layer was characterized for moisture content, bulk density, free air space (FAS) and air permeability (K). The results showed that the changes in material properties were different according to the considered layer. The deepest layer, impacted by the air inlet in the reactor, had the highest decrease of moisture content and bulk density, a steady K and the highest FAS increase, whereas the surface layer, impacted by a condensate dropout, showed a slight increase of moisture content, steady density and FAS, and a very strong increase of K. Then, a physical structural reorganization of material occurred during the process. In the future, the obtained results could help to improve composting models, taking into account the temporal and spatial distribution of physical properties in the porous media.}, }
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S. Huet, A. Shtiliyanova
Communication apprehension, self-esteem and the Leviathan model
Social Simulation Conference SSC 2014, 01/09/2014-05/09/2014, Barcelone, ESP (p. 11), 2014
abs web bib

Mc Corskey and al, 1977 have shown there is a link between a high aversion to oral communication and a lower self-esteem. We investigate if the Leviathan model which considers agents gossiping and having an opinion of each other (Deffuant et al 2013) is able to reproduce such a correlation. Our virtual agents form their opinions in face-to-face meetings. During these meetings, they act in self-defence applying vanity, and influence each other. They also gossip about their peers. In direct meeting and gossiping, a highly valued speaker compared to listener’s self-opinion is more influential. The vanity impact depends on the distance between one’s opinion of one self and the opinion conveyed by the speaker. Listeners felt held in low esteem sanction their speakers by decreasing their opinion of them. Those felt held in high esteem reward them by increasing their opinion of them. We modified the probability to talk of agents to consider a heterogeneous one: static depending on the agent itself, or dynamic depending on her self-esteem. The simplest law to obtain a heterogeneous probability to talk is sufficient to reproduce our search correlation. However, we also discover that the model argue it is possible to have a higher self-esteem for someone talking less than the others in some circumstances.
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@inproceedings{PUB00041835, author = {Huet, S. and Shtiliyanova, A.}, title = {Communication apprehension, self-esteem and the Leviathan model }, title = {Appréhension à la communication, estime de soi et modèle Léviathan}, bookTitle = {Social Simulation Conference SSC 2014, 01/09/2014-05/09/2014, Barcelone, ESP}, pages = {11}, url = {http://cemadoc.irstea.fr/cemoa/PUB00041835}, year = {2014}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; INRA CLERMONT FERRAND UR UREP FRA}, abstract = {Mc Corskey and al, 1977 have shown there is a link between a high aversion to oral communication and a lower self-esteem. We investigate if the Leviathan model which considers agents gossiping and having an opinion of each other (Deffuant et al 2013) is able to reproduce such a correlation. Our virtual agents form their opinions in face-to-face meetings. During these meetings, they act in self-defence applying vanity, and influence each other. They also gossip about their peers. In direct meeting and gossiping, a highly valued speaker compared to listener’s self-opinion is more influential. The vanity impact depends on the distance between one’s opinion of one self and the opinion conveyed by the speaker. Listeners felt held in low esteem sanction their speakers by decreasing their opinion of them. Those felt held in high esteem reward them by increasing their opinion of them. We modified the probability to talk of agents to consider a heterogeneous one: static depending on the agent itself, or dynamic depending on her self-esteem. The simplest law to obtain a heterogeneous probability to talk is sufficient to reproduce our search correlation. However, we also discover that the model argue it is possible to have a higher self-esteem for someone talking less than the others in some circumstances.}, }
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S. Huet, G. Deffuant
The Leviathan model
METACOG 2014, the 2nd International Conference on Metacognition, 09/09/2014-10/09/2014, Clermont-Ferrand, FRA , 2014
abs pdf bib

The Leviathan model simulates a group of agents holding opinions on each other. During dyadic meetings, they propagate their opinions of each other and of some other agents (gossip). Highly valued agents are more influential. Listeners decrease their opinion about the speaker when feeling undervalued and increase it when feeling overvalued. Various dynamic opinion structures emerge in the group: absolute dominance, hierarchy of opinions, crisis, equality and elite.
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@inproceedings{PUB00041831, author = {Huet, S. and Deffuant, G.}, title = {The Leviathan model}, title = {Le modèle Leviathan}, bookTitle = {METACOG 2014, the 2nd International Conference on Metacognition, 09/09/2014-10/09/2014, Clermont-Ferrand, FRA}, pdf = {http://motive.cemagref.fr/_publication/PUB00041831.pdf}, year = {2014}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {The Leviathan model simulates a group of agents holding opinions on each other. During dyadic meetings, they propagate their opinions of each other and of some other agents (gossip). Highly valued agents are more influential. Listeners decrease their opinion about the speaker when feeling undervalued and increase it when feeling overvalued. Various dynamic opinion structures emerge in the group: absolute dominance, hierarchy of opinions, crisis, equality and elite. }, }
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S. Huet, G. Deffuant
In the Leviathan Model, the average opinion is higher when vanity is weaker with lower valued agents
5th World Conference on Social Simulation (WCSS), 04/11/2014-07/11/2014, Sao Paulo, BRA (p. 12), 2014
abs web bib

In the Leviathan model, agents form opinions about each other. During dyadic meetings, they directly influence each other, or talk about peers through gossip. Speakers highly valued by their listeners are more influential. Moreover, they are subject to a vanity process; if an agent feels undervalued, then he decreases his opinion about the despising agent and on the contrary he increases his opinion about a compliment-giver agent. This model produces several different patterns depending on the parameter values, but the average opinion is always negative whatever the emerging pattern. As a consequence, the gossips tend to be mostly negative. Since this is not in complete accordance with the social–psychology literature indicating that both mostly negative and positive gossip can be observed, we investigate the changes to operate to obtain also mostly positive gossips. We found that when the vanity process is less triggered by agents held in low esteem, the average opinion significantly increases. We check that with this modification, the model still yields the same patterns.
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@inproceedings{PUB00041833, author = {Huet, S. and Deffuant, G.}, title = {In the Leviathan Model, the average opinion is higher when vanity is weaker with lower valued agents }, title = {Dans le modèle Leviathan, l'opinion moyenne est meilleure quand la vanité s'exerce moins avec les agents moindrement estimés}, bookTitle = {5th World Conference on Social Simulation (WCSS), 04/11/2014-07/11/2014, Sao Paulo, BRA}, pages = {12}, url = {http://cemadoc.irstea.fr/cemoa/PUB00041833}, year = {2014}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {In the Leviathan model, agents form opinions about each other. During dyadic meetings, they directly influence each other, or talk about peers through gossip. Speakers highly valued by their listeners are more influential. Moreover, they are subject to a vanity process; if an agent feels undervalued, then he decreases his opinion about the despising agent and on the contrary he increases his opinion about a compliment-giver agent. This model produces several different patterns depending on the parameter values, but the average opinion is always negative whatever the emerging pattern. As a consequence, the gossips tend to be mostly negative. Since this is not in complete accordance with the social–psychology literature indicating that both mostly negative and positive gossip can be observed, we investigate the changes to operate to obtain also mostly positive gossips. We found that when the vanity process is less triggered by agents held in low esteem, the average opinion significantly increases. We check that with this modification, the model still yields the same patterns.}, }
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J.D. Mathias, S. Huet, G. Deffuant
Bounded confidence model with fixed uncertainties and extremists: the opinions can keep fluctuating indefinitely
5th World Conference on Social Simulation (WCSS), 04/11/2014-07/11/2014, Sao Paulo, BRA (p. 12), 2014
abs web bib

The bounded confidence model and its variants applied to moderate and extremist agents exhibit three types of attractors: central clusters, double extreme and single extreme clusters. These attractors are observed when the models include a dynamics on the uncertainties tending to decrease the moderate uncertainties when interacting with extremists. We show here that a new stationary state appears when the uncertainties are fixed, for large uncertainties of the moderates. In this stationary state, the opinions of moderate agents keep fluctuating without clustering, altogether forming a stable density which shape changes significantly when the parameters vary.
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@inproceedings{PUB00041834, author = {Mathias, J.D. and Huet, S. and Deffuant, G.}, title = {Bounded confidence model with fixed uncertainties and extremists: the opinions can keep fluctuating indefinitely}, title = {Le modèle de confiance bornée avec des incertitudes fixes et des extrêmistes: les opinions peuvent changer indéfiniment}, bookTitle = {5th World Conference on Social Simulation (WCSS), 04/11/2014-07/11/2014, Sao Paulo, BRA}, pages = {12}, url = {http://cemadoc.irstea.fr/cemoa/PUB00041834}, year = {2014}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {The bounded confidence model and its variants applied to moderate and extremist agents exhibit three types of attractors: central clusters, double extreme and single extreme clusters. These attractors are observed when the models include a dynamics on the uncertainties tending to decrease the moderate uncertainties when interacting with extremists. We show here that a new stationary state appears when the uncertainties are fixed, for large uncertainties of the moderates. In this stationary state, the opinions of moderate agents keep fluctuating without clustering, altogether forming a stable density which shape changes significantly when the parameters vary. }, }
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S. Huet
Formes de leadership, défense de soi et commérage
Septièmes journées francophones Modèles Formels de l'Interaction, MFI'13, 01/07/2013-05/07/2013, Lille, FRA / http://pfia2013.univ-lille1.fr/doku.php%3Fid=fr:mfi.html (p. 15), 2013
abs pdf bib

Nous étudions une dynamique simplifiée du modèle Leviathan (Deffuant et al 2013) : les agents se rencontrent deux à deux de manière aléatoire et font évoluer les opinions qu’ils ont les uns des autres par des mécanismes de défense de soi et de propagation d’opinion sur des tiers. Nous nous intéressons à trois états de la population engendrés par ce modèle : la crise stigmatisée par une absence de leader ; la dominance où règne un leader quasi absolu mais renversable ; la hiérarchie au sein de laquelle chaque individu a son rang propre. Nous étudions l’effet de l’intensité du commérage inter-individuel mesuré via le nombre de personnes évoquées durant un face-à-face. Nous focalisons sur l’effet de l’ouverture aux autres qui amène un individu à être influencé par des individus qu’il n’estime pas. Nous montrons que partant d’une tendance systématique à l’état de crise, l’ouverture aux autres et le commérage permettent la mise en place d’un leadership charismatique stabilisant les relations inter-individus.
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@inproceedings{PUB00039556, author = {Huet, S.}, title = {Formes de leadership, défense de soi et commérage}, title = {Leadership styles, self-management and gossip}, bookTitle = {Septièmes journées francophones Modèles Formels de l'Interaction, MFI'13, 01/07/2013-05/07/2013, Lille, FRA / http://pfia2013.univ-lille1.fr/doku.php%3Fid=fr:mfi.html}, pages = {15}, pdf = {http://motive.cemagref.fr/_publication/PUB00039556.pdf}, year = {2013}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {Nous étudions une dynamique simplifiée du modèle Leviathan (Deffuant et al 2013) : les agents se rencontrent deux à deux de manière aléatoire et font évoluer les opinions qu’ils ont les uns des autres par des mécanismes de défense de soi et de propagation d’opinion sur des tiers. Nous nous intéressons à trois états de la population engendrés par ce modèle : la crise stigmatisée par une absence de leader ; la dominance où règne un leader quasi absolu mais renversable ; la hiérarchie au sein de laquelle chaque individu a son rang propre. Nous étudions l’effet de l’intensité du commérage inter-individuel mesuré via le nombre de personnes évoquées durant un face-à-face. Nous focalisons sur l’effet de l’ouverture aux autres qui amène un individu à être influencé par des individus qu’il n’estime pas. Nous montrons que partant d’une tendance systématique à l’état de crise, l’ouverture aux autres et le commérage permettent la mise en place d’un leadership charismatique stabilisant les relations inter-individus.}, }
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S. Huet
The target of the sel-management process makes the level of positivity to others
Interactions dans les systèmes complexes, 17/06/2013-19/06/2013, Orléans, FRA (p. 21), 2013
abs web bib

We study the Leviathan model in which individuals have opinions on each other (Deffuant et al 2013). The model couples the management of face-to-face meetings through direct interaction implying influence depending on esteem of the other and self-management (reward or punishment depending on the returned image by the other); and gossip having an influence depending of the level of esteem of the hearer for the talker. It is shown that the chosen target of the self-management process leads to a positive or a negative world. Mainly punishing or rewarding people held in high esteem can lead to a global positivity or global negativity to others while punishing or rewarding mostly everyone or only people held in low esteem leads to global negatives relationship. Moreover, choosing a self-management targeting more those held in high esteem keeps the same, and even enlarges, the richness of the various leaderships and organisations emerging from the model.
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@inproceedings{PUB00039555, author = {Huet, S.}, title = {The target of the sel-management process makes the level of positivity to others}, title = {La cible du processus de gestion de soi fait le niveau de positivité vis-à-vis d'autrui}, bookTitle = {Interactions dans les systèmes complexes, 17/06/2013-19/06/2013, Orléans, FRA}, pages = {21}, url = {http://cemadoc.irstea.fr/cemoa/PUB00039555}, year = {2013}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {We study the Leviathan model in which individuals have opinions on each other (Deffuant et al 2013). The model couples the management of face-to-face meetings through direct interaction implying influence depending on esteem of the other and self-management (reward or punishment depending on the returned image by the other); and gossip having an influence depending of the level of esteem of the hearer for the talker. It is shown that the chosen target of the self-management process leads to a positive or a negative world. Mainly punishing or rewarding people held in high esteem can lead to a global positivity or global negativity to others while punishing or rewarding mostly everyone or only people held in low esteem leads to global negatives relationship. Moreover, choosing a self-management targeting more those held in high esteem keeps the same, and even enlarges, the richness of the various leaderships and organisations emerging from the model.}, }
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M. Lenormand, S. Huet, G. Deffuant, F. Gargiulo
University laws in commuting flows
2013
abs pdf bib

We propose an individual based model to generate commuting networks from data giving numbers of in and out commuters of every locations of a region. It is inspired from the gravity model. We exhibit from the calibration of 80 various case studies that the only remaining parameter can be suppressed since it follows a law depending on the average surface of the locations. We compare our model to the only one other universal existing approach (Simini et al, 2012) at various scales. We show our model performs better for small locations (in terms of surface and/or number of inhabitants).
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@inproceedings{PUB00039558, author = {Lenormand, M. and Huet, S. and Deffuant, G. and Gargiulo, F.}, title = {University laws in commuting flows}, pages = {1}, pdf = {http://motive.cemagref.fr/_publication/PUB00039558.pdf}, year = {2013}, affiliation = {IFISC PALMA DE MALLORCA ESP ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; NAXYS UNAMUR NAMUR BEL}, abstract = {We propose an individual based model to generate commuting networks from data giving numbers of in and out commuters of every locations of a region. It is inspired from the gravity model. We exhibit from the calibration of 80 various case studies that the only remaining parameter can be suppressed since it follows a law depending on the average surface of the locations. We compare our model to the only one other universal existing approach (Simini et al, 2012) at various scales. We show our model performs better for small locations (in terms of surface and/or number of inhabitants).}, }
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M. Lenormand, S. Huet, G. Deffuant, F. Gargiulo
Universality laws in commuting flows
2013
abs web bib

We propose an individual based model to generate commuting networks from data giving numbers of in and out commuters of every locations of a region. It is inspired from the gravity model. We exhibit from the calibration of 80 various case studies that the only remaining parameter can be suppressed since it follows a law depending on the average surfaces of the locations. We compare our model to the only one other universal existing approach (Simini et al, 2012) at various scales. We show our model performs better for small locations (in terms of surface and/or number of inhabitants).
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@inproceedings{PUB00039020, author = {Lenormand, M. and Huet, S. and Deffuant, G. and Gargiulo, F.}, title = {Universality laws in commuting flows}, title = {Lois universelles des réseaux de navettage}, url = {http://cemadoc.irstea.fr/cemoa/PUB00039020}, year = {2013}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {We propose an individual based model to generate commuting networks from data giving numbers of in and out commuters of every locations of a region. It is inspired from the gravity model. We exhibit from the calibration of 80 various case studies that the only remaining parameter can be suppressed since it follows a law depending on the average surfaces of the locations. We compare our model to the only one other universal existing approach (Simini et al, 2012) at various scales. We show our model performs better for small locations (in terms of surface and/or number of inhabitants).}, }
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S. Huet, M. Lenormand, G. Deffuant
Modelling a network of rural municipalities
ESSA 2011, 19/09/2011-23/09/2011, Montpellier, FRA , 2011
abs web bib

The poster describes the dynamics of individuals changing activities and status on the labour market in a large individual-based model simulating the rural municipalities. Some results are presented for seven municipalities of the French Cantal department. / Ce poster décrit la dynamique d'activité des individus du modèle PRIMA dédié à la modélisation des municipalités rurales.
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@inproceedings{PUB00033512, author = {Huet,S. and Lenormand,M. and Deffuant,G.}, title = {Modelling a network of rural municipalities }, title = {La modélisation d'un réseau de municipalités rurales}, bookTitle = {ESSA 2011, 19/09/2011-23/09/2011, Montpellier, FRA}, url = {http://cemadoc.irstea.fr/cemoa/PUB00033512}, year = {2011}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {The poster describes the dynamics of individuals changing activities and status on the labour market in a large individual-based model simulating the rural municipalities. Some results are presented for seven municipalities of the French Cantal department. / Ce poster décrit la dynamique d'activité des individus du modèle PRIMA dédié à la modélisation des municipalités rurales.}, }
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M. Lenormand, G. Deffuant, S. Huet
Calibrating a complex social model
European Conference on Complex Systems ECCS'11, 12/09/2011-16/09/2011, Vienne, AUT , 2011
abs web bib

Approximate Bayesian computation is a family of computational techniques in Bayesian statistics. These techniques allow to fit a model to data without relying on the computation of the model likelihood. A number of improvements to the original ABC scheme have been proposed to speed it up. They include the coupling to Markov chain Monte Carlo to explore the parameter space and the sequential improvement of posterior distributions inspired by sequential Monte Carlo methods. These algorithms present severals shortcomings which are particularly problematic for costly to simulate complex models. In this article an adaptive appoximate Bayesian computation for complex models is proposed which offers improvements to circumvent the limitations of the application of the ABC methods to complex models. We demonstrate our algorithm on a toy example and on a complex social model, the PRIMA model.
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@inproceedings{PUB00033827, author = {Lenormand, M. and Deffuant, G. and Huet, S.}, title = {Calibrating a complex social model}, title = {Calibration d'un modèle social complexe}, bookTitle = {European Conference on Complex Systems ECCS'11, 12/09/2011-16/09/2011, Vienne, AUT}, url = {http://cemadoc.irstea.fr/cemoa/PUB00033827}, year = {2011}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {Approximate Bayesian computation is a family of computational techniques in Bayesian statistics. These techniques allow to fit a model to data without relying on the computation of the model likelihood. A number of improvements to the original ABC scheme have been proposed to speed it up. They include the coupling to Markov chain Monte Carlo to explore the parameter space and the sequential improvement of posterior distributions inspired by sequential Monte Carlo methods. These algorithms present severals shortcomings which are particularly problematic for costly to simulate complex models. In this article an adaptive appoximate Bayesian computation for complex models is proposed which offers improvements to circumvent the limitations of the application of the ABC methods to complex models. We demonstrate our algorithm on a toy example and on a complex social model, the PRIMA model.}, }
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M. Lenormand, G. Deffuant, S. Huet
A commuting generation model requiring only aggregated data
7th European Social Simulation Association Conference, 19/09/2011-23/09/2011, Montpellier, FRA (p. 16), 2011
abs web bib

We recently proposed, in (Gargiulo et al., 2011), an innovative stochastic model with only one parameter to calibrate. It reproduces the complete network by an iterative process stochastically choosing, for each commuter living in the municipality of a region, a workplace in the region. The choice is done considering the job offer in each municipality of the region and the distance to all the possible destinations. The model is quite effective if the region is sufficiently autonomous in terms of job offers. However, calibrating or being sure of this autonomy require data or expertise which are not necessarily available. Moreover the region can be not autonomous. In the present, we overcome these limitations, extending the job search geographical base of the commuters to the outside of the region, and changing the deterrence function form. We also found a law to calibrate the improvement model which does not require data.
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@inproceedings{PUB00033826, author = {Lenormand, M. and Deffuant, G. and Huet, S.}, title = {A commuting generation model requiring only aggregated data}, title = {Un modèle de génération de réseau de navettage nécessitant uniquement des données agrégées}, bookTitle = {7th European Social Simulation Association Conference, 19/09/2011-23/09/2011, Montpellier, FRA}, pages = {16}, url = {http://cemadoc.irstea.fr/cemoa/PUB00033826}, year = {2011}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {We recently proposed, in (Gargiulo et al., 2011), an innovative stochastic model with only one parameter to calibrate. It reproduces the complete network by an iterative process stochastically choosing, for each commuter living in the municipality of a region, a workplace in the region. The choice is done considering the job offer in each municipality of the region and the distance to all the possible destinations. The model is quite effective if the region is sufficiently autonomous in terms of job offers. However, calibrating or being sure of this autonomy require data or expertise which are not necessarily available. Moreover the region can be not autonomous. In the present, we overcome these limitations, extending the job search geographical base of the commuters to the outside of the region, and changing the deterrence function form. We also found a law to calibrate the improvement model which does not require data.}, }
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F. Gargiulo, S. Huet
When group level is different from the population level: an adaptive network with the Deffuant model
The Fifth International Workshop on Emergent Intelligence on Networked Agents ( WEIN 2010), 10/05/2010, Toronto, CAN (p. 7), 2010
abs pdf bib

We propose a model coupling the classical opinion dynamics of the bounded confidence model, proposed by Deffuant et al., with an adaptive network forming community or group structure. At each step, an individual can decide if it changes groups or interact on its opinion with one of its internal or external neighbour. If it decides to look at the group level, it changes group if its opinion is far from the average of its group from more than a threshold. If it is the case, it joins the group which has proportionally the closest average opinion from its. If it decides to interact with one of its neighbour, it becomes closer in opinion to it when its opinion and the one of the selected-to-interact neighbour are less distant from the threshold. From the study of this coupled model, we discover some surprising behaviours compared to the known behaviour of the Deffuant bounded confidence model(BC): The coupled model exhibits a total consensus for an threshold value lower than the BC model; the distribution of sizes of the groups changes: some groups become larger while other decrease in size, sometimes until containing only one individual. From the point of view of the groups, the consensus remains for a large set of threshold values while, looking at the population level, there are a lot of opinion clusters.
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@inproceedings{PUB00029107, author = {Gargiulo, F. and Huet, S.}, title = {When group level is different from the population level: an adaptive network with the Deffuant model}, title = {Lorsque le niveau "groupe" diffère du niveau "population" : un réseau adaptatif basé sur le modèle de Deffuant}, bookTitle = {The Fifth International Workshop on Emergent Intelligence on Networked Agents ( WEIN 2010), 10/05/2010, Toronto, CAN}, pages = {7}, pdf = {http://motive.cemagref.fr/_publication/PUB00029107.pdf}, year = {2010}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {We propose a model coupling the classical opinion dynamics of the bounded confidence model, proposed by Deffuant et al., with an adaptive network forming community or group structure. At each step, an individual can decide if it changes groups or interact on its opinion with one of its internal or external neighbour. If it decides to look at the group level, it changes group if its opinion is far from the average of its group from more than a threshold. If it is the case, it joins the group which has proportionally the closest average opinion from its. If it decides to interact with one of its neighbour, it becomes closer in opinion to it when its opinion and the one of the selected-to-interact neighbour are less distant from the threshold. From the study of this coupled model, we discover some surprising behaviours compared to the known behaviour of the Deffuant bounded confidence model(BC): The coupled model exhibits a total consensus for an threshold value lower than the BC model; the distribution of sizes of the groups changes: some groups become larger while other decrease in size, sometimes until containing only one individual. From the point of view of the groups, the consensus remains for a large set of threshold values while, looking at the population level, there are a lot of opinion clusters. }, }
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F. Gargiulo, S. Huet
How opinion dynamics generate group hierarchies
ECCS'10 European Conference on Complex Systems, 13/09/2010-17/09/2010, Lisbonne, PRT (p. 14), Actes électroniques, 2010
abs pdf bib

We recently proposed a model coupling the evolution of the opinions of the individual with the local network topology. The opinion dynamics is based on the Bounded Confidence model. The social networks is based on a group concept where each individual is totally connected to the members of its group and is linked to the individuals of the other groups with a given probability. During a time step, the individual has to decide between discussing with a member of its own network and applying the opinion dynamics, or moving groups because it has an opinion far from the average opinion of its own group. One of the main results we obtained is that the group sizes, starting from an homogenous situation can be strongly heterogeneous at the equilibrium state. This kind of heterogeneity can be identified in many real networks. In this paper we present the complete set of behaviours that this complex model can exhibit, at group level. In particular we will focus on the mechanisms that lead to the stability of the groups and the appearance of heterogeneity in sizes.
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@inproceedings{PUB00029105, author = {Gargiulo, F. and Huet, S.}, title = {How opinion dynamics generate group hierarchies}, title = {Comment la dynamique d'opinion engendre la hiérarchisation des groupes sociaux}, bookTitle = {ECCS'10 European Conference on Complex Systems, 13/09/2010-17/09/2010, Lisbonne, PRT}, publisher = {Actes électroniques}, pages = {14}, pdf = {http://motive.cemagref.fr/_publication/PUB00029105.pdf}, year = {2010}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {We recently proposed a model coupling the evolution of the opinions of the individual with the local network topology. The opinion dynamics is based on the Bounded Confidence model. The social networks is based on a group concept where each individual is totally connected to the members of its group and is linked to the individuals of the other groups with a given probability. During a time step, the individual has to decide between discussing with a member of its own network and applying the opinion dynamics, or moving groups because it has an opinion far from the average opinion of its own group. One of the main results we obtained is that the group sizes, starting from an homogenous situation can be strongly heterogeneous at the equilibrium state. This kind of heterogeneity can be identified in many real networks. In this paper we present the complete set of behaviours that this complex model can exhibit, at group level. In particular we will focus on the mechanisms that lead to the stability of the groups and the appearance of heterogeneity in sizes. }, }
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M. Lenormand, F. Garguilo, S. Huet
From the Auvergne commuting network to every commuting network
European Conference on Complex Systems ECCS'10 , 13/09/2010-17/09/2010, Lisbonne, PRT , 2010
web bib

@inproceedings{PUB00030598, author = {Lenormand, M. and Garguilo, F. and Huet, S.}, title = {From the Auvergne commuting network to every commuting network}, title = {Réseaux de navettage et caractérisation des communes}, bookTitle = {European Conference on Complex Systems ECCS'10 , 13/09/2010-17/09/2010, Lisbonne, PRT}, url = {http://www.eccs2010.eu/postersdemos}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00030598}, year = {2010}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {}, }
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S. Huet, G. Deffuant
Openness leads to Opinion Stability and Narrowness to Volatility
ECCS'09, European Conference on Complex Systems, 21/09/2009-25/09/2009, Warwick, GBR (p. 14), 2009
abs web bib

We propose a new opinion dynamic model based on the experiments and results of Wood et al (1996). We consider pairs of individuals discussing on two attitudinal dimensions, and we suppose that one dimension is important, the other secondary. The dynamics are mainly ruled by the level of agreement on the main dimension. If two individuals are close on the main dimension, then they attract each other on the main and on the secondary dimensions, whatever their disagreement on the secondary dimension. If they are far from each other on the main dimension, then too much proximity on the secondary dimension is uncomfortable, and generates rejection on this dimension. The proximity is defined by comparing the opinion distance with a threshold called attraction threshold on the main dimension and rejection threshold on the secondary dimension. With such dynamics, a population with opinions initially uniformly drawn evolves to a set of clusters, inside which secondary opinions fluctuate more or less depending on threshold values. We observe that a low attraction threshold favours fluctuations on the secondary dimension, especially when the rejection threshold is high. The trajectories of the model can be related to some stylised facts.
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@inproceedings{PUB00026801, author = {Huet, S. and Deffuant, G.}, title = {Openness leads to Opinion Stability and Narrowness to Volatility}, title = {L'ouverture d'esprit mène à la stabilité des opinions tandis que l'étroitesse les rend volatiles}, bookTitle = {ECCS'09, European Conference on Complex Systems, 21/09/2009-25/09/2009, Warwick, GBR}, pages = {14}, url = {http://cemadoc.irstea.fr/cemoa/PUB00026801}, year = {2009}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {We propose a new opinion dynamic model based on the experiments and results of Wood et al (1996). We consider pairs of individuals discussing on two attitudinal dimensions, and we suppose that one dimension is important, the other secondary. The dynamics are mainly ruled by the level of agreement on the main dimension. If two individuals are close on the main dimension, then they attract each other on the main and on the secondary dimensions, whatever their disagreement on the secondary dimension. If they are far from each other on the main dimension, then too much proximity on the secondary dimension is uncomfortable, and generates rejection on this dimension. The proximity is defined by comparing the opinion distance with a threshold called attraction threshold on the main dimension and rejection threshold on the secondary dimension. With such dynamics, a population with opinions initially uniformly drawn evolves to a set of clusters, inside which secondary opinions fluctuate more or less depending on threshold values. We observe that a low attraction threshold favours fluctuations on the secondary dimension, especially when the rejection threshold is high. The trajectories of the model can be related to some stylised facts.}, }
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S. Huet, G. Deffuant
De l'importance des individus moins engagés pour l'émergence d'une majorité
MASHS : Modèles et Apprentissage en Sciences Humaines et Sociales, 08/06/2009-09/06/2009, Toulouse, FRA (p. 12), 2009
abs web bib

Nous avons proposé un nouveau modèle de dynamique d'opinions basé sur les expériences et les résultats de Wood et al (1996). Un individu a plusieurs attitudes, chacune dotée d'une importance. L'importance de chaque attitude et la distance à un interlocuteur sur chacune des attitudes permet à l'individu de déterminer s'il juge la position de son interlocuteur positivement, négativement ou s'il y est indifférent. Lorsqu'il juge sa position positive, l'individu se rapproche de son interlocuteur sur toutes les dimensions attitudinales. Lorsqu'il la juge négativement, il s'éloigne sur les dimensions où il était proche. Une indifférence n'entraîne aucun changement d'attitude. Le modèle souligne d'une part l'importance de l'existence d'individus ne considérant pas une dimension plus importante que l'autre. Ces individus permettent l'émergence d'une majorité. Il montre également qu'en absence de tels individus, la population s'organise en petits groupes de taille homogène. Elle parvient à cet état en se rapprochant tout d'abord autour des questions peu importantes. Ce rapprochement rend saillant les divergences sur les questions importantes et incite les individus à s'organiser en petits groupes se repoussant et s'attirant en même temps.
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@inproceedings{PUB00026805, author = {Huet, S. and Deffuant, G.}, title = {De l'importance des individus moins engagés pour l'émergence d'une majorité}, title = {Less involved people are very important for a majority emergence}, bookTitle = {MASHS : Modèles et Apprentissage en Sciences Humaines et Sociales, 08/06/2009-09/06/2009, Toulouse, FRA}, pages = {12}, url = {http://cemadoc.irstea.fr/cemoa/PUB00026805}, year = {2009}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {Nous avons proposé un nouveau modèle de dynamique d'opinions basé sur les expériences et les résultats de Wood et al (1996). Un individu a plusieurs attitudes, chacune dotée d'une importance. L'importance de chaque attitude et la distance à un interlocuteur sur chacune des attitudes permet à l'individu de déterminer s'il juge la position de son interlocuteur positivement, négativement ou s'il y est indifférent. Lorsqu'il juge sa position positive, l'individu se rapproche de son interlocuteur sur toutes les dimensions attitudinales. Lorsqu'il la juge négativement, il s'éloigne sur les dimensions où il était proche. Une indifférence n'entraîne aucun changement d'attitude. Le modèle souligne d'une part l'importance de l'existence d'individus ne considérant pas une dimension plus importante que l'autre. Ces individus permettent l'émergence d'une majorité. Il montre également qu'en absence de tels individus, la population s'organise en petits groupes de taille homogène. Elle parvient à cet état en se rapprochant tout d'abord autour des questions peu importantes. Ce rapprochement rend saillant les divergences sur les questions importantes et incite les individus à s'organiser en petits groupes se repoussant et s'attirant en même temps.}, }
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S. Huet
Expérimentations en psychologie sociale et modélisation individu-centré de dynamique d'opinion. Apport de la confrontation des deux domaines de recherche au travers d'un exemple
16èmes Journées de Rochebrune. Rencontres Interdisciplinaires sur les Systèmes Complexes Naturels et Artificiels Ontologie et dynamique des systèmes complexes, perspectives interdisciplinaires, 19/01/2009-23/01/2009, Rochebrune, FRA (p. 11), 2009
abs web bib

La psychologie sociale pratique des expériences en laboratoire sur lesquelles elle fonde des théories du comportement individuel social en étudiant la dynamique des "attitudes". La simulation sociale pratique des expériences virtuelles sur un ordinateur en partant d'hypothèses sur le comportement individuel pour étudier les comportements collectifs (sociaux) obtenus. Nous confrontons ces deux domaines sur l'exemple des expériences de W. Wood (1996) dont nous proposons un modèle de dynamique d'opinion. Notre comparaison met en évidence les différences et les similitudes entre ces deux domaines. Elle permet une critique du travail de modélisation et donne un éclairage sur la façon d'utiliser les expériences de la psychologie pour la modélisation sociale.
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@inproceedings{PUB00026802, author = {Huet, S.}, title = {Expérimentations en psychologie sociale et modélisation individu-centré de dynamique d'opinion. Apport de la confrontation des deux domaines de recherche au travers d'un exemple }, title = {Social psychology experimentations and individual based modelling of opinion dynamic. Confrontation through an example of these two research domains}, bookTitle = {16èmes Journées de Rochebrune. Rencontres Interdisciplinaires sur les Systèmes Complexes Naturels et Artificiels Ontologie et dynamique des systèmes complexes, perspectives interdisciplinaires, 19/01/2009-23/01/2009, Rochebrune, FRA}, pages = {11}, url = {http://cemadoc.irstea.fr/cemoa/PUB00026802}, year = {2009}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {La psychologie sociale pratique des expériences en laboratoire sur lesquelles elle fonde des théories du comportement individuel social en étudiant la dynamique des "attitudes". La simulation sociale pratique des expériences virtuelles sur un ordinateur en partant d'hypothèses sur le comportement individuel pour étudier les comportements collectifs (sociaux) obtenus. Nous confrontons ces deux domaines sur l'exemple des expériences de W. Wood (1996) dont nous proposons un modèle de dynamique d'opinion. Notre comparaison met en évidence les différences et les similitudes entre ces deux domaines. Elle permet une critique du travail de modélisation et donne un éclairage sur la façon d'utiliser les expériences de la psychologie pour la modélisation sociale.}, }
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S. Ternès, F. Gargiulo, S. Huet, G. Deffuant
Double modelling of the dynamic of activities in rural municipalities
7th Brazilian Congress of Agro-informatics (7. Congresso Brasileiro de Agroinformática ), 21/09/2009-25/09/2009, Viçosa, BRA (p. 5), 2009
abs web bib

Land use choices and activity prevalence in a selected territory are determined by individual preferences constrained by the characteristic of the analysed zone: population density, soil properties, urbanization level and other similar factors can drive individuals to make different kind of decisions about their occupations. Different approaches can be used to describe land use change, occupation prevalence and their reciprocal inter-relation. In this paper we describe two different kinds of approaches: an agent based model, centred on individual choices and an aggregated model describing the evolution of activity prevalence in terms of coupled differential equation. We use and we compare the two models to analyse the effect of territorial constraints, like the lack of employment in determined sectors, on the possible activity prevalence scenarios.
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@inproceedings{PUB00026804, author = {Ternès, S. and Gargiulo, F. and Huet, S. and Deffuant, G.}, title = {Double modelling of the dynamic of activities in rural municipalities}, bookTitle = {7th Brazilian Congress of Agro-informatics (7. Congresso Brasileiro de Agroinformática ), 21/09/2009-25/09/2009, Viçosa, BRA}, pages = {5}, url = {http://cemadoc.irstea.fr/cemoa/PUB00026804}, year = {2009}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {Land use choices and activity prevalence in a selected territory are determined by individual preferences constrained by the characteristic of the analysed zone: population density, soil properties, urbanization level and other similar factors can drive individuals to make different kind of decisions about their occupations. Different approaches can be used to describe land use change, occupation prevalence and their reciprocal inter-relation. In this paper we describe two different kinds of approaches: an agent based model, centred on individual choices and an aggregated model describing the evolution of activity prevalence in terms of coupled differential equation. We use and we compare the two models to analyse the effect of territorial constraints, like the lack of employment in determined sectors, on the possible activity prevalence scenarios.}, }
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S. Huet, G. Deffuant
Bounded confidence with rejection: clusters or scattered opinions ?
5th Conference of the European Social Simulation Association ESSA 2008, 01/09/2008-05/09/2008, Brescia, ITA / Proceedings of the Fifth Conference of the European Social Simulation Association (ESSA'08) (p. 12), University of Brescia, Brescia, ITA, 2008
abs web bib

Huet and Deffuant (2007) propose a new opinion dynamics model based on the bounded confidence principles, with a rejection mechanism. We study new simulations of the agent-based model for a population of 10000 individuals. We generally observe fewer clusters than the classical bounded confidence model, and below a threshold of the uncertainty, no cluster appear: all opinions remain scattered. We build an aggregated model of this agent-based model (ABM), in the limit case of an infinite population, in order to better understand this dynamical behaviour. When adding a small perturbation in the initial distribution, the aggregated model and ABM yield similar numbers of clusters for the same parameters. Below a critical value of uncertainty, the aggregated model forms no cluster and the distribution remains uniform. The critical value is higher for the aggregated model than for the ABM, indicating a finite size effect that we discuss.
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@inproceedings{PUB00024581, author = {Huet, S. and Deffuant, G.}, title = {Bounded confidence with rejection: clusters or scattered opinions ?}, title = {Confiance bornée avec rejet: organisation en groupe d'opinion ou changement permanent d'opinion}, bookTitle = {5th Conference of the European Social Simulation Association ESSA 2008, 01/09/2008-05/09/2008, Brescia, ITA / Proceedings of the Fifth Conference of the European Social Simulation Association (ESSA'08)}, address = {Brescia, ITA}, publisher = {University of Brescia}, pages = {12}, url = {http://cemadoc.irstea.fr/cemoa/PUB00024581}, year = {2008}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {Huet and Deffuant (2007) propose a new opinion dynamics model based on the bounded confidence principles, with a rejection mechanism. We study new simulations of the agent-based model for a population of 10000 individuals. We generally observe fewer clusters than the classical bounded confidence model, and below a threshold of the uncertainty, no cluster appear: all opinions remain scattered. We build an aggregated model of this agent-based model (ABM), in the limit case of an infinite population, in order to better understand this dynamical behaviour. When adding a small perturbation in the initial distribution, the aggregated model and ABM yield similar numbers of clusters for the same parameters. Below a critical value of uncertainty, the aggregated model forms no cluster and the distribution remains uniform. The critical value is higher for the aggregated model than for the ABM, indicating a finite size effect that we discuss.}, }
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S. Huet, G. Deffuant
Bounded confidence with rejection: the infinite population limit with perfect uniform initial density
Modèles et Apprentissages en Sciences Humaines et Sociales (MASH), 05/06/2008-06/06/2008, Créteil, FRA (p. 10), 2008
abs web bib

Huet and Deffuant (2007) propose a new opinion dynamics model based on the bounded confidence principles, with a rejection mechanism. The simulations of the agent-based model show that this new model leads generally to fewer clusters than the classical bounded confidence model. We build an aggregated model of this agent-based model (ABM), considering the limit case of an infinite population, in order to better understand the clustering process in the ABM. The dynamics of the aggregated model, starting from a perfectly uniform distribution of opinions, and the dynamics of the ABM are significantly different. However, the aggregated model provides relevant information about how the rejection mechanism and bounding the attitude space influence the clustering process. It firstly outlines that, with a perfectly symmetric density, the clustering process is almost impossible and that the only final stable state is one centred cluster. Secondly we notice that one centred cluster can be lead with the only rejection mechanism or with an unbounded attitude space.
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@inproceedings{PUB00024188, author = {Huet, S. and Deffuant, G.}, title = {Bounded confidence with rejection: the infinite population limit with perfect uniform initial density}, title = {Confiance limitée et rejet: l'effet d'une taille de population infinie pour une densité initiale parfaitement uniforme}, bookTitle = {Modèles et Apprentissages en Sciences Humaines et Sociales (MASH), 05/06/2008-06/06/2008, Créteil, FRA}, pages = {10}, url = {http://cemadoc.irstea.fr/cemoa/PUB00024188}, year = {2008}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {Huet and Deffuant (2007) propose a new opinion dynamics model based on the bounded confidence principles, with a rejection mechanism. The simulations of the agent-based model show that this new model leads generally to fewer clusters than the classical bounded confidence model. We build an aggregated model of this agent-based model (ABM), considering the limit case of an infinite population, in order to better understand the clustering process in the ABM. The dynamics of the aggregated model, starting from a perfectly uniform distribution of opinions, and the dynamics of the ABM are significantly different. However, the aggregated model provides relevant information about how the rejection mechanism and bounding the attitude space influence the clustering process. It firstly outlines that, with a perfectly symmetric density, the clustering process is almost impossible and that the only final stable state is one centred cluster. Secondly we notice that one centred cluster can be lead with the only rejection mechanism or with an unbounded attitude space.}, }
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S. Huet, G. Deffuant, W. Jager
Des dynamiques de différenciation individuelle peuvent accroître le conformisme global
ARCo'07, Cognition - Complexité - Collectif, Nancy - Loria, 28-30 novembre 2007 (p. 89-102), Acta-Cognitica, Nancy - Loria, 2007
abs web bib

Dans le modèle de dynamiques d'attitudes (ou opinions) à "confiance limitée" (CL), deux individus se rapprochent lors d'une rencontre si leur différence est inférieure à un seuil. Nous considérons des individus avec deux attitudes, et nous ajoutons au modèle CL un mécanisme de rejet. Si deux individus sont très éloignés sur la première attitude et très proches sur la seconde, alors ils résolvent la contradiction en s'éloignant l'un de l'autre sur la seconde attitude. En considérant une population d'individus initialement aléatoirement distribués, le modèle exhibe des attracteurs composés de groupes métastables dans l'espace 2D, qui se maintiennent dans une compétition entre attraction et rejet. L'analyse du modèle et les simulations montrent que le nombre final de groupes croît linéairement avec l'inverse de l'incertitude des individus, alors qu'il croît quadratiquement dans le modèle CL en 2D.
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@inproceedings{PUB00022902, author = {Huet, S. and Deffuant, G. and Jager, W.}, title = {Des dynamiques de différenciation individuelle peuvent accroître le conformisme global}, title = {Individual differentiation dynamic can increase the global conformism}, bookTitle = {ARCo'07, Cognition - Complexité - Collectif, Nancy - Loria, 28-30 novembre 2007}, address = {Nancy - Loria}, publisher = {Acta-Cognitica}, pages = {89-102}, url = {http://cemadoc.irstea.fr/cemoa/PUB00022902}, year = {2007}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; FACULTY OF ECONOMICS UNIVERSITY OF GRONINGEN NLD}, abstract = {Dans le modèle de dynamiques d'attitudes (ou opinions) à "confiance limitée" (CL), deux individus se rapprochent lors d'une rencontre si leur différence est inférieure à un seuil. Nous considérons des individus avec deux attitudes, et nous ajoutons au modèle CL un mécanisme de rejet. Si deux individus sont très éloignés sur la première attitude et très proches sur la seconde, alors ils résolvent la contradiction en s'éloignant l'un de l'autre sur la seconde attitude. En considérant une population d'individus initialement aléatoirement distribués, le modèle exhibe des attracteurs composés de groupes métastables dans l'espace 2D, qui se maintiennent dans une compétition entre attraction et rejet. L'analyse du modèle et les simulations montrent que le nombre final de groupes croît linéairement avec l'inverse de l'incertitude des individus, alors qu'il croît quadratiquement dans le modèle CL en 2D.}, }
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S. Huet, G. Deffuant
When do interactions increase or decrease primacy effect?
M2M 2007, Third International Model-to-Model Workshop, Marseille, France, 15-16 mars 2007 (p. 102-120), 2007
abs web bib

We propose an individual based model of attitude dynamics which, in some conditions, reproduces primacy effect behaviours. The primacy effect takes place when the attitude of an individual depends on the reception order of features describing an object. Typically, when receiving a strong negative feature first, the individual keeps a negative attitude whatever the number of moderate positive features it receives afterwards. We consider a population of individuals which receive the features from a media, and communicate with each other: in some cases, interactions increase the number of individuals exhibiting a primacy effect, in other cases they decrease this number. To better understand this phenomenon, we developed aggregated models of the individual based model with interaction.
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@inproceedings{PUB00022656, author = {Huet, S. and Deffuant, G.}, title = {When do interactions increase or decrease primacy effect?}, title = {Quand l'interaction faire croître ou décroître l'effet de primauté}, bookTitle = {M2M 2007, Third International Model-to-Model Workshop, Marseille, France, 15-16 mars 2007}, pages = {102-120}, url = {http://cemadoc.irstea.fr/cemoa/PUB00022656}, year = {2007}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {We propose an individual based model of attitude dynamics which, in some conditions, reproduces primacy effect behaviours. The primacy effect takes place when the attitude of an individual depends on the reception order of features describing an object. Typically, when receiving a strong negative feature first, the individual keeps a negative attitude whatever the number of moderate positive features it receives afterwards. We consider a population of individuals which receive the features from a media, and communicate with each other: in some cases, interactions increase the number of individuals exhibiting a primacy effect, in other cases they decrease this number. To better understand this phenomenon, we developed aggregated models of the individual based model with interaction.}, }
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S. Huet, G. Deffuant, W. Jager
Rejection mechanism in 2D bounded confidence provides more conformity
ECCS'07, European Conference on Complex Systems, Dresden, Allemagne (DEU) 1-6 october 2007 (p. 16), 2007
abs web bib

This paper explores the dynamics of attitude change on 2 dimensions (2D) as a result of social interaction. We add a rejection mechanism into a 2D bounded confidence (BC) model. The principle is that one shifts away from a close attitude of one's interlocutor, when there is a strong disagreement on the other attitude. The model shows metastable clusters, which maintain themselves through opposite influences of competitor clusters. Our analysis and first experiments support the hypothesis that the number of clusters grows linearly with the inverse of the uncertainty, whereas this growth is quadratic in the BC model.
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@inproceedings{PUB00022655, author = {Huet, S. and Deffuant, G. and Jager, W.}, title = {Rejection mechanism in 2D bounded confidence provides more conformity}, title = {Un mécanisme de rejet au sein d'un modèle de confiance limitée deux dimensions engendre davantage de conformisme}, bookTitle = {ECCS'07, European Conference on Complex Systems, Dresden, Allemagne (DEU) 1-6 october 2007}, pages = {16}, url = {http://cemadoc.irstea.fr/cemoa/PUB00022655}, year = {2007}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; FACULTY OF ECONOMICS UNIVERSITY OF GRONINGEN PAYS- BAS NLD}, abstract = {This paper explores the dynamics of attitude change on 2 dimensions (2D) as a result of social interaction. We add a rejection mechanism into a 2D bounded confidence (BC) model. The principle is that one shifts away from a close attitude of one's interlocutor, when there is a strong disagreement on the other attitude. The model shows metastable clusters, which maintain themselves through opposite influences of competitor clusters. Our analysis and first experiments support the hypothesis that the number of clusters grows linearly with the inverse of the uncertainty, whereas this growth is quadratic in the BC model.}, }
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S. Huet, G. Deffuant
Sensitivity of primacy effect to interactions
EuroCogSci07, Delphes, GRC, 23-27 mai 2007 / Proceedings of EuroCogSci07/Stella Vosniadou, Daniel Kayser, Athanassios Protopapas (p. 830-835), Hellenic Cognitive Science Society, 2007
abs web bib

We propose an individual based model of attitude dynamics which, in some conditions, reproduces primacy effect behaviours. The primacy effect takes place when the attitude of an individual depends on the reception order of features describing an object. Typically, when receiving a strong negative feature first, the individual keeps a negative attitude whatever the number of moderate positive features it receives afterwards. We consider a population of individuals which receive the features from a media, and communicate with each other: in some cases, interactions increase the number of individuals exhibiting a primacy effect, in other cases they decrease this number. We study the sensitivity of this phenomenon to the interaction structure and to the part of the population with an initial negative attitude.
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@inproceedings{PUB00021807, author = {Huet, S. and Deffuant, G.}, title = {Sensitivity of primacy effect to interactions}, title = {Impact de l'interaction sur l'effet de primauté}, bookTitle = {EuroCogSci07, Delphes, GRC, 23-27 mai 2007 / Proceedings of EuroCogSci07/Stella Vosniadou, Daniel Kayser, Athanassios Protopapas}, address = {Hellenic Cognitive Science Society}, pages = {830-835}, url = {http://cemadoc.irstea.fr/cemoa/PUB00021807}, year = {2007}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {We propose an individual based model of attitude dynamics which, in some conditions, reproduces primacy effect behaviours. The primacy effect takes place when the attitude of an individual depends on the reception order of features describing an object. Typically, when receiving a strong negative feature first, the individual keeps a negative attitude whatever the number of moderate positive features it receives afterwards. We consider a population of individuals which receive the features from a media, and communicate with each other: in some cases, interactions increase the number of individuals exhibiting a primacy effect, in other cases they decrease this number. We study the sensitivity of this phenomenon to the interaction structure and to the part of the population with an initial negative attitude.}, }
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G. Deffuant, S. Huet
Collective reinforcement of first impression Bias
WCSS'06 The First World Congress on Social Simulation, Kyoto (Japon) 21-25 aout 2006 (p. 8), 2006
abs web bib

We propose a simple model of attitude dynamics in which an agent tends to ignore the features which contradict its views. For instance, having received a first very negative feature, the agent may stop to consider any moderately positive feature. We call this phenomenon first impression bias (FIB). We consider a population of agents which are all in contact with a media, communicating randomly chosen features of an object. In some cases, we observe on simulations that FIB is significantly more frequent when the agents interact with each other than when they are only in contact with the media. We design an analytical aggregated model of the global agent-based model behaviour which helps to explain the higher number of FIB due to the interactions.
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@inproceedings{PUB00020378, author = {Deffuant, G. and Huet, S.}, title = {Collective reinforcement of first impression Bias}, title = {Renforcement collectif du bias de première impression}, bookTitle = {WCSS'06 The First World Congress on Social Simulation, Kyoto (Japon) 21-25 aout 2006}, pages = {8}, url = {http://cemadoc.irstea.fr/cemoa/PUB00020378}, year = {2006}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {We propose a simple model of attitude dynamics in which an agent tends to ignore the features which contradict its views. For instance, having received a first very negative feature, the agent may stop to consider any moderately positive feature. We call this phenomenon first impression bias (FIB). We consider a population of agents which are all in contact with a media, communicating randomly chosen features of an object. In some cases, we observe on simulations that FIB is significantly more frequent when the agents interact with each other than when they are only in contact with the media. We design an analytical aggregated model of the global agent-based model behaviour which helps to explain the higher number of FIB due to the interactions.}, }
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G. Deffuant, S. Huet
Propagation effects of filtering incongruent information
Agent Based Model of Consumer Behaviour Workshop, Janvier 2006, Guilford, GBR (p. 8), 2006
abs web bib

We propose a simple individual-based model of information filtering and study some of its implications on the attitude about an object. The model assumes that a filter selects only important features, with a higher threshold of importance when the attitude about the feature is incongruent with the global attitude about the object. Moreover, we suppose that individuals transmit only features which are congruent with their global attitude. We consider two variants of this model. For both of them, different orders of feature reception can lead to different attitudes. For instance, an individual with a positive attitude about the object, can finally become negative, even though the object is globally neutral (the sum of the feature attitudes is 0). The interactions among individuals can significantly increase the probability of such non-rational attitudes.
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@inproceedings{PUB00020382, author = {Deffuant, G. and Huet, S.}, title = {Propagation effects of filtering incongruent information}, title = {Effet sur la diffusion du filtrage des informations incongruentes}, bookTitle = {Agent Based Model of Consumer Behaviour Workshop, Janvier 2006, Guilford, GBR}, pages = {8}, url = {http://cemadoc.irstea.fr/cemoa/PUB00020382}, year = {2006}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {We propose a simple individual-based model of information filtering and study some of its implications on the attitude about an object. The model assumes that a filter selects only important features, with a higher threshold of importance when the attitude about the feature is incongruent with the global attitude about the object. Moreover, we suppose that individuals transmit only features which are congruent with their global attitude. We consider two variants of this model. For both of them, different orders of feature reception can lead to different attitudes. For instance, an individual with a positive attitude about the object, can finally become negative, even though the object is globally neutral (the sum of the feature attitudes is 0). The interactions among individuals can significantly increase the probability of such non-rational attitudes.}, }
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S. Huet, G. Deffuant
Effets d'un filtre cognitif sur la diffusion d'information
MOSIM'06, 6ème Conférence Francophone de Modélisation, Simulation, Rabat, MAR, 3 au 5 avril 2006 (p. 10), 2006
abs web bib

Les recherches sur la diffusion de l'information montrent que les individus ne la retiennent et ne la propagent pas nécessairement. Nous proposons un modèle simple de ce phénomène. Les individus s'échangent des informations relatives à un objet décrit par des facettes dont l'utilité est positive ou négative. La possession d'une information correspond au fait de disposer de l'utilité d'une facette. Les individus disposent par ailleurs d'une opinion globale a priori sur l'objet. Lors des discussions, les facettes dont l'utilité en valeur absolue est inférieure à un seuil d'intérêt sont ignorées et ne sont pas reçues. Ce seuil est plus élevé lorsque l'utilité et l'opinion globale sont de signes contraires. En outre, un individu ne parle pas des facettes qu'il possède lorsque leur utilité est de signe contraire à son opinion globale. L'étude du modèle à convergence, lorsque tous échangent avec tous, permet le recensement des états finaux et souligne l'importance des caractéristiques des premiers individus qui reçoivent l'information. Nous étudions le modèle pour une population dont les individus échangent avec un nombre constant et faible de voisins, dans le cas «une seule information, de même utilité pour tous, un seul individu source initial » grâce à un calcul approché de la distribution de probabilités du nombre final d'individus possédant l'information. Le nombre de voisins modifie cette distribution car il limite la rencontre entre des individus à même de diffuser l'information
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@inproceedings{PUB00019444, author = {Huet, S. and Deffuant, G.}, title = {Effets d'un filtre cognitif sur la diffusion d'information}, title = {Cognitive filter effects on the information diffusion process}, bookTitle = {MOSIM'06, 6ème Conférence Francophone de Modélisation, Simulation, Rabat, MAR, 3 au 5 avril 2006}, pages = {10}, url = {http://cemadoc.irstea.fr/cemoa/PUB00019444}, year = {2006}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {Les recherches sur la diffusion de l'information montrent que les individus ne la retiennent et ne la propagent pas nécessairement. Nous proposons un modèle simple de ce phénomène. Les individus s'échangent des informations relatives à un objet décrit par des facettes dont l'utilité est positive ou négative. La possession d'une information correspond au fait de disposer de l'utilité d'une facette. Les individus disposent par ailleurs d'une opinion globale a priori sur l'objet. Lors des discussions, les facettes dont l'utilité en valeur absolue est inférieure à un seuil d'intérêt sont ignorées et ne sont pas reçues. Ce seuil est plus élevé lorsque l'utilité et l'opinion globale sont de signes contraires. En outre, un individu ne parle pas des facettes qu'il possède lorsque leur utilité est de signe contraire à son opinion globale. L'étude du modèle à convergence, lorsque tous échangent avec tous, permet le recensement des états finaux et souligne l'importance des caractéristiques des premiers individus qui reçoivent l'information. Nous étudions le modèle pour une population dont les individus échangent avec un nombre constant et faible de voisins, dans le cas «une seule information, de même utilité pour tous, un seul individu source initial » grâce à un calcul approché de la distribution de probabilités du nombre final d'individus possédant l'information. Le nombre de voisins modifie cette distribution car il limite la rencontre entre des individus à même de diffuser l'information}, }
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S. Huet, M. Edwards, G. Deffuant
Taking into account the variations of social network in the mean-field approximation of the threshold behaviour diffusion model
ESSA Conference, Model to Model workshop, Valladolid, ESP, 16-19/09/2004 (p. 15), 2004
abs web bib

We compare the individual-based "threshold model" of innovation diffusion in the version which has been studied by Young, with an aggregate model we derived from it. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure and a personal interest. Our study considers only the case where all have the same threshold. We present an aggregated model, which takes into account variations of the neighbourhood sizes, whereas previous work assumed this size fixed. The comparison between the aggregated models (the first one assuming a neighbourhood size and the second one, a variable one) points out an improvement of the approximation in most of the value of parameter space. Remaining differences between both models give us some clues about the specific ability of individual-based model to maintain a minority behaviour which becomes a majority by an addition of stochastic effects. / Nous comparons un modèle individu-centré de diffusion de l`innovation (modèle à seuil) proposé par Young à ses approximations agrégées. Le classique modèle à seuil suppose qu`un individu adopte un comportement en fonction des valeurs relatives de la pression sociale qu`il subit et de son intérêt personnel pour ce comportement. Notre étude considère uniquement le cas où tous les individus ont même seuil. Nous présentons un modèle agrégé qui prend en compte la variation de la taille du voisinage d`un individu à l`autre alors que les précédents travaux supposait ce voisinage de taille constante pour tous les individus. La comparaison entre les modèles agrégés (un à voisinage de taille fixe, l`autre à voisinage de taille variable) montre une amélioration de l`approximation pour la plupart des valeurs de l`espace des paramètres. Les différences restantes entre les deux types de modèles nous fournissent quelques indicateurs sur les spécificités du modèle individu-centré, et notamment sur sa capacité à maintenir au sein de la population un comportement minoritaire qui peut, du fait de la stochasticité du modèle, devenir le comportement de la majorité.
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@inproceedings{PUB00017647, author = {Huet, S. and Edwards, M. and Deffuant, G.}, title = {Taking into account the variations of social network in the mean-field approximation of the threshold behaviour diffusion model}, title = {Prise en compte du caractère aléatoire du réseau social dans une approximation par champs moyen d`un modèle à seuil de diffusion d`un comportement}, bookTitle = {ESSA Conference, Model to Model workshop, Valladolid, ESP, 16-19/09/2004}, pages = {15}, url = {http://cemadoc.irstea.fr/cemoa/PUB00017647}, year = {2004}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {We compare the individual-based "threshold model" of innovation diffusion in the version which has been studied by Young, with an aggregate model we derived from it. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure and a personal interest. Our study considers only the case where all have the same threshold. We present an aggregated model, which takes into account variations of the neighbourhood sizes, whereas previous work assumed this size fixed. The comparison between the aggregated models (the first one assuming a neighbourhood size and the second one, a variable one) points out an improvement of the approximation in most of the value of parameter space. Remaining differences between both models give us some clues about the specific ability of individual-based model to maintain a minority behaviour which becomes a majority by an addition of stochastic effects. / Nous comparons un modèle individu-centré de diffusion de l`innovation (modèle à seuil) proposé par Young à ses approximations agrégées. Le classique modèle à seuil suppose qu`un individu adopte un comportement en fonction des valeurs relatives de la pression sociale qu`il subit et de son intérêt personnel pour ce comportement. Notre étude considère uniquement le cas où tous les individus ont même seuil. Nous présentons un modèle agrégé qui prend en compte la variation de la taille du voisinage d`un individu à l`autre alors que les précédents travaux supposait ce voisinage de taille constante pour tous les individus. La comparaison entre les modèles agrégés (un à voisinage de taille fixe, l`autre à voisinage de taille variable) montre une amélioration de l`approximation pour la plupart des valeurs de l`espace des paramètres. Les différences restantes entre les deux types de modèles nous fournissent quelques indicateurs sur les spécificités du modèle individu-centré, et notamment sur sa capacité à maintenir au sein de la population un comportement minoritaire qui peut, du fait de la stochasticité du modèle, devenir le comportement de la majorité.}, }
close
S. Huet, M. Edwards, G. Deffuant
Taking into account the variations of social network in the mean-field approximation of the threshold behaviour diffusion model
ESSA Conference Model to Model workshop, Valladolid, ESP, 16-19 septembre 2004 (p. 15), 2004
abs web bib

We compare the individual-based "threshold model" of innovation diffusion in the version which has been studied by Young, with an aggregate model we derived from it. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure and a personal interest. Our study considers only the case where all have the same threshold. We present an aggregated model, which takes into account variations of the neighbourhood sizes, whereas previous work assumed this size fixed. The comparison between the aggregated models (the first one assuming a neighbourhood size and the second one, a variable one) points out an improvement of the approximation in most of the value of parameter space. Remaining differences between both models give us some clues about the specific ability of individual-based model to maintain a minority behaviour which becomes a majority by an addition of stochastic effects. / Nous comparons un modèle individu-centré de diffusion de l`innovation (modèle à seuil) proposé par Young à ses approximations agrégées. Le classique modèle à seuil suppose qu`un individu adopte un comportement en fonction des valeurs relatives de la pression sociale qu`il subit et de son intérêt personnel pour ce comportement. Notre étude considère uniquement le cas où tous les individus ont même seuil. Nous présentons un modèle agrégé qui prend en compte la variation de la taille du voisinage d`un individu à l`autre alors que les précédents travaux supposait ce voisinage de taille constante pour tous les individus. La comparaison entre les modèles agrégés (un à voisinage de taille fixe, l`autre à voisinage de taille variable) montre une amélioration de l`approximation pour la plupart des valeurs de l`espace des paramètres. Les différences restantes entre les deux types de modèles nous fournissent quelques indicateurs sur les spécificités du modèle individu-centré, et notamment sur sa capacité à maintenir au sein de la population un comportement minoritaire qui peut, du fait de la stochasticité du modèle, devenir le comportement de la majorité.
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@inproceedings{PUB00016301, author = {Huet, S. and Edwards, M. and Deffuant, G.}, title = {Taking into account the variations of social network in the mean-field approximation of the threshold behaviour diffusion model}, title = {Prise en compte du caractère aléatoire du réseau social dans une approximation par champ moyen d`un modèle à seuil de diffusion d`un comportement}, bookTitle = {ESSA Conference Model to Model workshop, Valladolid, ESP, 16-19 septembre 2004}, pages = {15}, url = {http://cemadoc.irstea.fr/cemoa/PUB00016301}, year = {2004}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, abstract = {We compare the individual-based "threshold model" of innovation diffusion in the version which has been studied by Young, with an aggregate model we derived from it. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure and a personal interest. Our study considers only the case where all have the same threshold. We present an aggregated model, which takes into account variations of the neighbourhood sizes, whereas previous work assumed this size fixed. The comparison between the aggregated models (the first one assuming a neighbourhood size and the second one, a variable one) points out an improvement of the approximation in most of the value of parameter space. Remaining differences between both models give us some clues about the specific ability of individual-based model to maintain a minority behaviour which becomes a majority by an addition of stochastic effects. / Nous comparons un modèle individu-centré de diffusion de l`innovation (modèle à seuil) proposé par Young à ses approximations agrégées. Le classique modèle à seuil suppose qu`un individu adopte un comportement en fonction des valeurs relatives de la pression sociale qu`il subit et de son intérêt personnel pour ce comportement. Notre étude considère uniquement le cas où tous les individus ont même seuil. Nous présentons un modèle agrégé qui prend en compte la variation de la taille du voisinage d`un individu à l`autre alors que les précédents travaux supposait ce voisinage de taille constante pour tous les individus. La comparaison entre les modèles agrégés (un à voisinage de taille fixe, l`autre à voisinage de taille variable) montre une amélioration de l`approximation pour la plupart des valeurs de l`espace des paramètres. Les différences restantes entre les deux types de modèles nous fournissent quelques indicateurs sur les spécificités du modèle individu-centré, et notamment sur sa capacité à maintenir au sein de la population un comportement minoritaire qui peut, du fait de la stochasticité du modèle, devenir le comportement de la majorité.}, }
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M. Edwards, S. Huet, F. Goreaud, G. Deffuant
Comparing an innovation diffusion IBM and its aggregated version derived by mean field approximation for short term simulations
Modèles formels de l'interaction (MFI03), Lille, 20-22 mai 2003 (p. 11), 2003
abs web bib

We compare two models at short term (200 time steps) models. On the one hand, a stochastic individual based model of innovation diffusion (Valente 1995) inspired from the game theory, in which the probability for an individual to make the choice suggested by the social pressure follows a Gibb's function, whose asymptotic behaviour has been described in (Young, 1999). On the other hand, a deterministic aggregate model which we derive from the previous one by considering an average network and following a mean field approximation.For a particular zone in the parameter space, which we studied and where the aggregated model has two equilibrium points, there exist differences between the two models at short term and they are located around the limit between two attractions basins existing for the aggrgated model. When aggregated model has only one equilibrium point, the two models are equivalent. / Nous utilisons un modèle de diffusion de l'innovation (Valente 1995) pour lequel la probabilité d'un individu d'opter pour le choix suggéré par la pression sociale suit une fonction de Gibbs. Ce modèle individu-centré stochastique, dont Young (1999) a étudié et décrit le comportement asymptotique, est comparé à un modèle agrégé déterministe dérivé du modèle individu-centré par une approche de type champ moyen. Nous écrivons l'équation maîtresse régissant l'évolution des probabilités des différentes configurations de ce réseau moyen et déterminons la part de chacun des comportements dans la population. Pour un sous-ensemble de paramètres étudiés, des différences entre ces deux modèles existent et se situent autour de la limite du bassin d'attraction du modèle agrégé lorsque celui-ci est doté de deux points d'équilibre stable. Ces différences apparaissent à court terme. Par ailleurs, lorsque le modèle agrégé n'a qu'un point d'équilibre, il n'y a aucune différence entre les deux modèles.
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@inproceedings{PUB00011530, author = {Edwards, M. and Huet, S. and Goreaud, F. and Deffuant, G.}, title = {Comparing an innovation diffusion IBM and its aggregated version derived by mean field approximation for short term simulations}, title = {Comparaison entre un modèle individu-centré de diffusion et sa version agrégée dérivée par champ moyen pour des simulations à court terme}, bookTitle = {Modèles formels de l'interaction (MFI03), Lille, 20-22 mai 2003}, pages = {11}, url = {http://cemadoc.irstea.fr/cemoa/PUB00011530}, year = {2003}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, number = {03/0089 ; K LI03 4}, abstract = {We compare two models at short term (200 time steps) models. On the one hand, a stochastic individual based model of innovation diffusion (Valente 1995) inspired from the game theory, in which the probability for an individual to make the choice suggested by the social pressure follows a Gibb's function, whose asymptotic behaviour has been described in (Young, 1999). On the other hand, a deterministic aggregate model which we derive from the previous one by considering an average network and following a mean field approximation.For a particular zone in the parameter space, which we studied and where the aggregated model has two equilibrium points, there exist differences between the two models at short term and they are located around the limit between two attractions basins existing for the aggrgated model. When aggregated model has only one equilibrium point, the two models are equivalent. / Nous utilisons un modèle de diffusion de l'innovation (Valente 1995) pour lequel la probabilité d'un individu d'opter pour le choix suggéré par la pression sociale suit une fonction de Gibbs. Ce modèle individu-centré stochastique, dont Young (1999) a étudié et décrit le comportement asymptotique, est comparé à un modèle agrégé déterministe dérivé du modèle individu-centré par une approche de type champ moyen. Nous écrivons l'équation maîtresse régissant l'évolution des probabilités des différentes configurations de ce réseau moyen et déterminons la part de chacun des comportements dans la population. Pour un sous-ensemble de paramètres étudiés, des différences entre ces deux modèles existent et se situent autour de la limite du bassin d'attraction du modèle agrégé lorsque celui-ci est doté de deux points d'équilibre stable. Ces différences apparaissent à court terme. Par ailleurs, lorsque le modèle agrégé n'a qu'un point d'équilibre, il n'y a aucune différence entre les deux modèles.}, }
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M. Edwards, S. Huet, F. Goreaud, G. Deffuant
Comparing individual-based model of behaviour diffusion with its mean field aggregated approximation
Model to model (M2M), Marseille, 31 mars et 1er avril 2003 (p. 12), 2003
abs web bib

We compare the individual-based "threshold model"of innovation diffusion (Valente 1995), in the version which has been studied by P. Young, and an aggregate deterministic model we constructed from it. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure (the number of neighbours adopting the behaviour) and a personal interest or resistance to change (the threshold). The aggregate model makes approximations in order to estimate the evolution of groups of individuals with the same number of neighbours of similar behaviour. We compare both models in different points of the parameter space. We find that the aggregate model gives a good approximation of the indicidual in some cases ; however, in other cases the behaviour of the aggregate approximations differs. Using theoretical interpretation of this difference based on a study of the attractors of the aggregate model, we hypothesed that the two models have the same behaviour when the aggregate model has only one attractor and that differences can occur when it has two. / Nous comparons un modèle individu-centré à seuil de diffusion de l'innovation (Valente 1995) dans la version étudiée par P. Young, et un modèle agrégé déterministe que nous avons construit en cohérence. Le modèle classique de diffusion de l'innovation à seuil suppose qu'un individu adopte un comportement suivant un compromis entre la pression sociale (le nombre de ses voisins ayant adopté ce comportement) et un intérêt personnel de résistance au changement (le seuil). Le modèle agrégé fait appel à des approximations pour estimer l'évolution de groupes d'individus ayant le même nombre de voisins suivant un certain comportement. Nous comparons ces deux modèles en différents points de l'espace des paramètres. Nous trouvons que le modèle agrégé approxime bien le modèle individu-centré dans certains cas ; toutefois, il s'avère également parfois que le comportement du modèle agrégé diffère. En nous appuyant sur une interprétation théorique de cette différence, fondée sur une étude des attracteurs du modèle agrégé, nous proposons l'hypothèse que les deux modèles suivent le même comportement lorsque le modèle agrégé n'a qu'un seul attracteur, et que des différences peuvent apparaître quand il en a deux.
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@inproceedings{PUB00011529, author = {Edwards, M. and Huet, S. and Goreaud, F. and Deffuant, G.}, title = {Comparing individual-based model of behaviour diffusion with its mean field aggregated approximation}, title = {Comparaison d'un modèle individu-centré de diffusion de l'innovation avec son approximation par champ moyen}, bookTitle = {Model to model (M2M), Marseille, 31 mars et 1er avril 2003}, pages = {12}, url = {http://cemadoc.irstea.fr/cemoa/PUB00011529}, year = {2003}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, number = {03/0088 ; K LI03 3}, abstract = {We compare the individual-based "threshold model"of innovation diffusion (Valente 1995), in the version which has been studied by P. Young, and an aggregate deterministic model we constructed from it. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure (the number of neighbours adopting the behaviour) and a personal interest or resistance to change (the threshold). The aggregate model makes approximations in order to estimate the evolution of groups of individuals with the same number of neighbours of similar behaviour. We compare both models in different points of the parameter space. We find that the aggregate model gives a good approximation of the indicidual in some cases ; however, in other cases the behaviour of the aggregate approximations differs. Using theoretical interpretation of this difference based on a study of the attractors of the aggregate model, we hypothesed that the two models have the same behaviour when the aggregate model has only one attractor and that differences can occur when it has two. / Nous comparons un modèle individu-centré à seuil de diffusion de l'innovation (Valente 1995) dans la version étudiée par P. Young, et un modèle agrégé déterministe que nous avons construit en cohérence. Le modèle classique de diffusion de l'innovation à seuil suppose qu'un individu adopte un comportement suivant un compromis entre la pression sociale (le nombre de ses voisins ayant adopté ce comportement) et un intérêt personnel de résistance au changement (le seuil). Le modèle agrégé fait appel à des approximations pour estimer l'évolution de groupes d'individus ayant le même nombre de voisins suivant un certain comportement. Nous comparons ces deux modèles en différents points de l'espace des paramètres. Nous trouvons que le modèle agrégé approxime bien le modèle individu-centré dans certains cas ; toutefois, il s'avère également parfois que le comportement du modèle agrégé diffère. En nous appuyant sur une interprétation théorique de cette différence, fondée sur une étude des attracteurs du modèle agrégé, nous proposons l'hypothèse que les deux modèles suivent le même comportement lorsque le modèle agrégé n'a qu'un seul attracteur, et que des différences peuvent apparaître quand il en a deux.}, }
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Miscellaneous (2)

G. Deffuant, S. Huet, T. Carletti
Leviathan model: vanity generating general distrust or absolute dominance
INTERACTIONS 2011 - Mathematical Sciences to the proof of Human & Social Sciences, 30/05/2011-31/05/2011, Paris, FRA (p. 21), 2011
abs web bib

We propose a simple model made of a population of agents where each one has an opinion about each of the others. The agents interact by randomly chosen pairs and include two different dynamics. One represents gossips where agents propagate their opinions about themselves and some other agents. In this propagation, they influence more the agents that have a good opinion of them. The second dynamics is a vanity effect: an agent likes to get a good opinion of herself from the others, thus she increases her opinion on those who propagate such a good opinion. On the contrary she tends to decrease her opinion about those who propagate a bad opinion (good and bad are relative to the opinion the agent has on herself). The combination of these dynamics shows interesting emergent properties. First, a general distrust tends to prevail for most of the model parameter values: each agent tends to have a negative average opinion about the others. For some parameters, this situation of general distrust leads to the emergence of one or a few agents who are highly considered by all the others, sometimes followed by a hierarchy of reputations with intermediate values. For some parameters, this situation systematically unstable and always ends suddenly with the return to a generalised distrust. We some partial explanations of the mechanisms behind these emergent behaviours.
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@misc{PUB00034526, note = {Conférence invitée}, author = {Deffuant, G. and Huet, S. and Carletti, T.}, title = {Leviathan model: vanity generating general distrust or absolute dominance}, title = {Le modèle Léviathan : la vanité peut engendrer la défiance généralisée ou la domination absolue}, bookTitle = {INTERACTIONS 2011 - Mathematical Sciences to the proof of Human & Social Sciences, 30/05/2011-31/05/2011, Paris, FRA}, pages = {21}, url = {http://cemadoc.irstea.fr/cemoa/PUB00034526}, year = {2011}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; UNIVERSITE DE NAMUR BEL}, abstract = {We propose a simple model made of a population of agents where each one has an opinion about each of the others. The agents interact by randomly chosen pairs and include two different dynamics. One represents gossips where agents propagate their opinions about themselves and some other agents. In this propagation, they influence more the agents that have a good opinion of them. The second dynamics is a vanity effect: an agent likes to get a good opinion of herself from the others, thus she increases her opinion on those who propagate such a good opinion. On the contrary she tends to decrease her opinion about those who propagate a bad opinion (good and bad are relative to the opinion the agent has on herself). The combination of these dynamics shows interesting emergent properties. First, a general distrust tends to prevail for most of the model parameter values: each agent tends to have a negative average opinion about the others. For some parameters, this situation of general distrust leads to the emergence of one or a few agents who are highly considered by all the others, sometimes followed by a hierarchy of reputations with intermediate values. For some parameters, this situation systematically unstable and always ends suddenly with the return to a generalised distrust. We some partial explanations of the mechanisms behind these emergent behaviours.}, }
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M. Lenormand, S. Huet, G. Deffuant
Predicting the presence and the number of jobs in different services in Auvergne municipalities
2010
abs web bib

Nous décrivons dans ce rapport une méthode permettant de prédire la présence de différents services (école, boulangerie...) dans une commune en fonction des caractéristiques de celle-ci. Nous présentons aussi une méthode permettant de prédire le nombre d'emplois dans différentes sortes de services. Les deux méthodes sont testées sur les communes d'Auvergne.
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@misc{PUB00035311, note = {Autres}, author = {Lenormand, M. and Huet, S. and Deffuant, G.}, title = {Predicting the presence and the number of jobs in different services in Auvergne municipalities}, title = {Prédire la présence et le nombre d'emplois dans les services pour les communes d'Auvergne}, pages = {9}, url = {http://cemadoc.irstea.fr/cemoa/PUB00035311}, year = {2010}, affiliation = {CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA ; CEMAGREF CLERMONT FERRAND UR LISC FRA}, abstract = {Nous décrivons dans ce rapport une méthode permettant de prédire la présence de différents services (école, boulangerie...) dans une commune en fonction des caractéristiques de celle-ci. Nous présentons aussi une méthode permettant de prédire le nombre d'emplois dans différentes sortes de services. Les deux méthodes sont testées sur les communes d'Auvergne.}, }
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Dissertations (3)

S. Huet
Individual based models of social systems: data driven hybrid micro-models of rural development and collective dynamics of filtering or rejecting messages
Doctorat en Informatique, Université Blaise Pascal Clermont-Ferrand, 2013
abs pdf bib

This thesis is composed in two parts, both dedicated to individual-based modeling of social systems. While the first part is very practical, decision-support oriented, presenting a model which studies the evolution of a rural population, the second part is more theoretical, interested in various mechanisms allowing individual to accept or resist to social influence. In the first part, we propose an individual-based model of the European rural municipalities and describe its implementation for a French region: the Cantal département. We use a new sample-free algorithm for generating the initial population, while classical methods require an initial sample. We design and parameterize the individual activity dynamics with data from the European Labour Force Survey database. The individual dynamics includes an original heuristic for labour statuses and employments changes, based on individual age, profession and activity sector when she is occupied. The last part of the model deals with dynamics that we have not been able to derive from data, mainly the demographic dynamics. Based on the Occam razor principle, we test very simple dynamics and choose them on their capacity to lead to model results close to reference data from the French National Statistical Office. In particular, we propose a simple residential mobility model, partly ruling the emigration, which integrates decision to move and location choice. In the second part, with a more theoretical approach, we study the collective effects of various mechanisms leading individuals to resist or accept social influence. A first mechanism leads individuals to neglect some features of an object if they are not important enough or incongruent. These individuals exhibit the primacy bias because their attitudes are determined by the first accepted feature. We show that this bias increases when individuals directly exchange about features compared to when they only get the features from the media, in a random order. The second mechanism is a rejection reaction that we suppose occurring because of the discomfort taking place when individuals are close on one dimension of attitude and far on another dimension. The main effect of this rejection mechanism is to lead to a lower number of clusters than with the attraction mechanism alone. A discussion of these models with respect to the social psychology literature ends this part. Finally, I discuss the complementarity between the approaches presented in the two parts of this document and try to identify some perspectives based on this complementarity.
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@phdthesis{PUB00037754, author = {Huet, S.}, title = {Individual based models of social systems: data driven hybrid micro-models of rural development and collective dynamics of filtering or rejecting messages }, title = {Modèles individus-centrés de systèmes sociaux: micro-modèles hybrides inspirés de données du développement rural, dynamiques collectives de filtrage et/ou de rejet de messages}, publisher = {Doctorat en Informatique, Université Blaise Pascal Clermont-Ferrand}, pages = {252}, pdf = {http://motive.cemagref.fr/_publication/PUB00037754.pdf}, year = {2013}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA}, abstract = {This thesis is composed in two parts, both dedicated to individual-based modeling of social systems. While the first part is very practical, decision-support oriented, presenting a model which studies the evolution of a rural population, the second part is more theoretical, interested in various mechanisms allowing individual to accept or resist to social influence. In the first part, we propose an individual-based model of the European rural municipalities and describe its implementation for a French region: the Cantal département. We use a new sample-free algorithm for generating the initial population, while classical methods require an initial sample. We design and parameterize the individual activity dynamics with data from the European Labour Force Survey database. The individual dynamics includes an original heuristic for labour statuses and employments changes, based on individual age, profession and activity sector when she is occupied. The last part of the model deals with dynamics that we have not been able to derive from data, mainly the demographic dynamics. Based on the Occam razor principle, we test very simple dynamics and choose them on their capacity to lead to model results close to reference data from the French National Statistical Office. In particular, we propose a simple residential mobility model, partly ruling the emigration, which integrates decision to move and location choice. In the second part, with a more theoretical approach, we study the collective effects of various mechanisms leading individuals to resist or accept social influence. A first mechanism leads individuals to neglect some features of an object if they are not important enough or incongruent. These individuals exhibit the primacy bias because their attitudes are determined by the first accepted feature. We show that this bias increases when individuals directly exchange about features compared to when they only get the features from the media, in a random order. The second mechanism is a rejection reaction that we suppose occurring because of the discomfort taking place when individuals are close on one dimension of attitude and far on another dimension. The main effect of this rejection mechanism is to lead to a lower number of clusters than with the attraction mechanism alone. A discussion of these models with respect to the social psychology literature ends this part. Finally, I discuss the complementarity between the approaches presented in the two parts of this document and try to identify some perspectives based on this complementarity. }, }
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S. Huet
Modélisation et exploration de modèles : modèle individus-centré versus modèle agrégé
Diplôme d'ingénieur CNAM (centre régional Auvergne) en informatique, modélisation, optimisation, 2005
abs web bib

This work is focussed on individual-based models. There are often used to represent complex systems like social systems, ecosystems, ~ The main idea consists in representing individuals (actors or organisms) and their interactions. The global behaviour (aggregated variables) of these models is difficult to predict and requires specific investigation methods, as experimental protocols. In a first part, I have analysed and tested the prototyping implementations of a software devoted to such exploration (SimExplorer). In a second part, an individual-based model of binary behaviour diffusion in a population of individuals interacting in a neighbourhood network (based on Blume, 1993) is studied and compared to a model trying to reproduce its global dynamic. Starting from an approximation of the individual-based model written by Edwards (2003a), I am improving the prediction rate of final state by proposing a new aggregated model which takes into account the random feature of the neighbouring network. This work allows to better understand the individual-based model behaviour and to quickly calculate the final state when values of the parameter are far from those which drive the model into an unstable region. It shows than certain trajectory of the individual-based model, after falling in a local minimum of energy (which corresponding to a poor minority of adopters of the observed behaviour), are able to converge into a state where all individuals are adopters after a favourable series of events. The aggregated model itself stays in the local minimum. / Ce travail porte sur les modèles individus-centrés qui sont fréquemment utilisés pour représenter des systèmes complexes et/ou mal connus : systèmes sociaux, écosystèmes, ~ Leur caractéristique est de représenter explicitement les individus (acteurs ou organismes) et leurs interactions. Le comportement global (agrégé sur la population) de ces modèles est souvent difficile a prévoir et requiert des méthodes d`investigation particulières, fondées notamment sur des plans d`expériences simulatoires systématiques. Dans une première partie, j`ai analysé et testé les développements exploratoires d`un outil logiciel permettant de mettre en oeuvre de telles explorations (SimExplorer). Dans une seconde partie, un modèle individus-centré de diffusion d`un comportement binaire au sein d`une population d`individus interagissant au sein d`un réseau d`accointances (basé sur Blume, 1993) est étudié en le comparant à un modèle cherchant à reproduire sa dynamique globale. Partant d`une approximation du modèle individus-centré écrite par Edwards (2003a), j`améliore le taux de prédiction de l`état final en proposant un nouveau modèle agrégé prenant en compte le caractère aléatoire du réseau de voisinage. Ce travail permet de mieux comprendre le comportement du modèle individus-centré et d`en déterminer quasi-instantanément l`état final lorsque les valeurs de paramètres retenues sont loin de celles entraînant le modèle sur une de ces zones d`instabilité. Il montre que le modèle individus-centré exhibe des trajectoires pour lesquelles, après être tombé dans un minimum local d`énergie correspondant à une faible minorité d`adoptants du comportement observé, il est à même, au gré d`une suite d`événements favorables de sortir de ce minimum pour atteindre l`état final où tous les individus de la population ont adopté le ce comportement. Le modèle agrégé, pour sa part, reste dans le minimum local.
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@phdthesis{PUB00017196, author = {Huet, S.}, title = {Modélisation et exploration de modèles : modèle individus-centré versus modèle agrégé}, title = {Modelisation and exploration:individual-based model versus agreggated model}, publisher = {Diplôme d'ingénieur CNAM (centre régional Auvergne) en informatique, modélisation, optimisation}, pages = {147}, url = {http://cemadoc.irstea.fr/cemoa/PUB00017196}, year = {2005}, affiliation = {CEMAGREF CLERMONT FERRAND LISC}, abstract = {This work is focussed on individual-based models. There are often used to represent complex systems like social systems, ecosystems, ~ The main idea consists in representing individuals (actors or organisms) and their interactions. The global behaviour (aggregated variables) of these models is difficult to predict and requires specific investigation methods, as experimental protocols. In a first part, I have analysed and tested the prototyping implementations of a software devoted to such exploration (SimExplorer). In a second part, an individual-based model of binary behaviour diffusion in a population of individuals interacting in a neighbourhood network (based on Blume, 1993) is studied and compared to a model trying to reproduce its global dynamic. Starting from an approximation of the individual-based model written by Edwards (2003a), I am improving the prediction rate of final state by proposing a new aggregated model which takes into account the random feature of the neighbouring network. This work allows to better understand the individual-based model behaviour and to quickly calculate the final state when values of the parameter are far from those which drive the model into an unstable region. It shows than certain trajectory of the individual-based model, after falling in a local minimum of energy (which corresponding to a poor minority of adopters of the observed behaviour), are able to converge into a state where all individuals are adopters after a favourable series of events. The aggregated model itself stays in the local minimum. / Ce travail porte sur les modèles individus-centrés qui sont fréquemment utilisés pour représenter des systèmes complexes et/ou mal connus : systèmes sociaux, écosystèmes, ~ Leur caractéristique est de représenter explicitement les individus (acteurs ou organismes) et leurs interactions. Le comportement global (agrégé sur la population) de ces modèles est souvent difficile a prévoir et requiert des méthodes d`investigation particulières, fondées notamment sur des plans d`expériences simulatoires systématiques. Dans une première partie, j`ai analysé et testé les développements exploratoires d`un outil logiciel permettant de mettre en oeuvre de telles explorations (SimExplorer). Dans une seconde partie, un modèle individus-centré de diffusion d`un comportement binaire au sein d`une population d`individus interagissant au sein d`un réseau d`accointances (basé sur Blume, 1993) est étudié en le comparant à un modèle cherchant à reproduire sa dynamique globale. Partant d`une approximation du modèle individus-centré écrite par Edwards (2003a), j`améliore le taux de prédiction de l`état final en proposant un nouveau modèle agrégé prenant en compte le caractère aléatoire du réseau de voisinage. Ce travail permet de mieux comprendre le comportement du modèle individus-centré et d`en déterminer quasi-instantanément l`état final lorsque les valeurs de paramètres retenues sont loin de celles entraînant le modèle sur une de ces zones d`instabilité. Il montre que le modèle individus-centré exhibe des trajectoires pour lesquelles, après être tombé dans un minimum local d`énergie correspondant à une faible minorité d`adoptants du comportement observé, il est à même, au gré d`une suite d`événements favorables de sortir de ce minimum pour atteindre l`état final où tous les individus de la population ont adopté le ce comportement. Le modèle agrégé, pour sa part, reste dans le minimum local. }, }
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S. Huet
Modéliser les interactions sociales par des réseaux d`automates à seuil. Approximation d`un réseau aléatoire d`automates binaires
DEA Informatique, Productique, Imagerie médicale ; option Recherche Opérationnelle et Productique, Université Clermont II, 2004
abs web bib

The three first part of the document are a non-exhaustive state-of-the-art of social modelling. The question of aggregation level of modelling is discussed and studied in the last part.This one compares the individual-based "threshold model" of innovation diffusion in the version which has been studied by Young, with an aggregate model we derived from it. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure and a personal interest. This study consider only the case where all have the same threshold. An aggregated model, which takes into account variations of the neighbourhood sizes, whereas previous work assumed this size fixed, is presented. The comparison between the aggregated models (the first one assuming a neighbourhood size and the second one, a variable one) points out the improvement of the approximation in most of the value of parameter space. Remaining differences between both model give us some clues about the specific ability of individual-based model to maintain a minority behaviour which becomes a majority by an addition of stochastic effects. Modélisation, interactions sociales, degré de finesse / La première partie de ce document s`attache à présenter les cadres de réflexion originaux prévalent à la modélisation sociale. Deux axes principaux sont identifiés : la sociologie des réseaux qui rencontre la sociologie de l`innovation pour engendrer le paradigme de la diffusion de l`innovation qui s`enrichira plus tard de celui des « small world » ; la théorie des jeux qui engendre les jeux évolutionnaires. Dans les deux cas, la nécessité d`une approche centrée sur l`individu est mise en avant. Grimm (1999) définit les modèles individus-centré comme des modèles de simulation traitant l`individu comme entité unique et discrète ayant au moins un attribut. Il recense en écologie les raisons pour lesquelles cette approche est utilisée. La première est pragmatique : l`approche individus-centrée permet de modéliser des phénomènes non modélisables de façon agrégée et notamment les variations individuelles. La seconde est paradigmatique : elle porte sur l`étude du système, a pour objet la connaissance de celui-ci et permet éventuellement de corriger une théorie dont les principes sont fondés sur l`observable au niveau global. En économie, on entend parler d` « interactions-based model » (Brock W.A., Durlauf S.N., 2000). Ces modèles permettent de modéliser explicitement les individus du système et de vérifier l`hypothèse formulant que ce qui est observable au niveau global émerge des interactions entre les entités du système. L`idée sous-jacente est que des règles d`évolution individuelle quelquefois très simples suffisent à expliquer des évolutions apparemment très complexes au niveau global qu`est celui du système.La suite de ce document présente des modèles mathématiques permettant de décrire les interactions. La seconde partie est consacrée aux modèles purement individus-centrés qui calculent un changement d`état pour chacun des individus de la population. Nous y découvrirons les réseaux d`automates qui conçoivent l`état d`une entité appelée automate comme dépendant de l`état des automates auxquels elle est liée et d`un seuil traduisant sa sensibilité à ses pairs. L`enrichissement de la problématique par les travaux des chercheurs des jeux évolutionnistes y est également présenté. De même, quelques travaux sur les topologies des structures d`interactions sont introduits de façon à mieux appréhender le cas particulier qui est traité par la suite.La troisième partie présente des modèles philosophiquement centrés sur l`individu mais pour lesquels le changement d`état est calculé pour une sous-partie de la population. Nous appelons ces modèles des modèles agrégés d`interactions. Ces modèles considèrent en effet l`évolution d`agrégats. Ils supposent que l`interaction de chacun des individus de l`agrégat entre eux et avec le restant de la population est équivalente du point de vue de la description du système à l`interaction de cet agrégat avec les autres agrégats considérés. En quatrième partie, la question de la comparaison entre modèle individus-centré et modèle agrégé est abordée au travers de la présentation d`une étude réalisée par M. Edwards (Edwards et al., 2003a 2003b ; Huet, Edwards et al., 2004) dans le cadre de sa thèse (M. Edwards, 2004) et poursuivie par S. Huet.
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@phdthesis{PUB00014086, author = {Huet, S.}, title = {Modéliser les interactions sociales par des réseaux d`automates à seuil. Approximation d`un réseau aléatoire d`automates binaires}, title = {Modelling social interactions by an automata threshold networks. Approximation of a random network of binary automata}, publisher = {DEA Informatique, Productique, Imagerie médicale ; option Recherche Opérationnelle et Productique, Université Clermont II}, pages = {90}, url = {http://cemadoc.irstea.fr/cemoa/PUB00014086}, year = {2004}, affiliation = {CEMAGREF CLERMONT FERRAND LISC}, number = {LI04 1}, abstract = {The three first part of the document are a non-exhaustive state-of-the-art of social modelling. The question of aggregation level of modelling is discussed and studied in the last part.This one compares the individual-based "threshold model" of innovation diffusion in the version which has been studied by Young, with an aggregate model we derived from it. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure and a personal interest. This study consider only the case where all have the same threshold. An aggregated model, which takes into account variations of the neighbourhood sizes, whereas previous work assumed this size fixed, is presented. The comparison between the aggregated models (the first one assuming a neighbourhood size and the second one, a variable one) points out the improvement of the approximation in most of the value of parameter space. Remaining differences between both model give us some clues about the specific ability of individual-based model to maintain a minority behaviour which becomes a majority by an addition of stochastic effects. Modélisation, interactions sociales, degré de finesse / La première partie de ce document s`attache à présenter les cadres de réflexion originaux prévalent à la modélisation sociale. Deux axes principaux sont identifiés : la sociologie des réseaux qui rencontre la sociologie de l`innovation pour engendrer le paradigme de la diffusion de l`innovation qui s`enrichira plus tard de celui des « small world » ; la théorie des jeux qui engendre les jeux évolutionnaires. Dans les deux cas, la nécessité d`une approche centrée sur l`individu est mise en avant. Grimm (1999) définit les modèles individus-centré comme des modèles de simulation traitant l`individu comme entité unique et discrète ayant au moins un attribut. Il recense en écologie les raisons pour lesquelles cette approche est utilisée. La première est pragmatique : l`approche individus-centrée permet de modéliser des phénomènes non modélisables de façon agrégée et notamment les variations individuelles. La seconde est paradigmatique : elle porte sur l`étude du système, a pour objet la connaissance de celui-ci et permet éventuellement de corriger une théorie dont les principes sont fondés sur l`observable au niveau global. En économie, on entend parler d` « interactions-based model » (Brock W.A., Durlauf S.N., 2000). Ces modèles permettent de modéliser explicitement les individus du système et de vérifier l`hypothèse formulant que ce qui est observable au niveau global émerge des interactions entre les entités du système. L`idée sous-jacente est que des règles d`évolution individuelle quelquefois très simples suffisent à expliquer des évolutions apparemment très complexes au niveau global qu`est celui du système.La suite de ce document présente des modèles mathématiques permettant de décrire les interactions. La seconde partie est consacrée aux modèles purement individus-centrés qui calculent un changement d`état pour chacun des individus de la population. Nous y découvrirons les réseaux d`automates qui conçoivent l`état d`une entité appelée automate comme dépendant de l`état des automates auxquels elle est liée et d`un seuil traduisant sa sensibilité à ses pairs. L`enrichissement de la problématique par les travaux des chercheurs des jeux évolutionnistes y est également présenté. De même, quelques travaux sur les topologies des structures d`interactions sont introduits de façon à mieux appréhender le cas particulier qui est traité par la suite.La troisième partie présente des modèles philosophiquement centrés sur l`individu mais pour lesquels le changement d`état est calculé pour une sous-partie de la population. Nous appelons ces modèles des modèles agrégés d`interactions. Ces modèles considèrent en effet l`évolution d`agrégats. Ils supposent que l`interaction de chacun des individus de l`agrégat entre eux et avec le restant de la population est équivalente du point de vue de la description du système à l`interaction de cet agrégat avec les autres agrégats considérés. En quatrième partie, la question de la comparaison entre modèle individus-centré et modèle agrégé est abordée au travers de la présentation d`une étude réalisée par M. Edwards (Edwards et al., 2003a 2003b ; Huet, Edwards et al., 2004) dans le cadre de sa thèse (M. Edwards, 2004) et poursuivie par S. Huet.}, }
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Technical Reports (4)

S. Huet, N. Dumoulin, G. Deffuant, F. Gargiulo, M. Lenormand, O. Baqueiro Espinosa, S. Ternes
Micro-simulation model of municipality network in the Auvergne case study
2012
abs pdf bib

How do European rural areas evolve? Some tend to decrease dramatically, as in the Netherlands or in the United Kingdom, where the urban areas tend to spread all over the country. Their population can also be drastically depleting through a large rural exodus, as observed in for instance France, Bulgaria or Croatia in the first part of the last Century. They can also keep steady population densities occupied in leisure services offered to urban people and agriculture with various proportions of inhabitants commuting to the cities for their work. Better understanding these evolutions is what the PRIMA simulation model presented in this report is interested in. / Ce document décrit un modèle de micro-simulation de communes développé dans le cadre du projet européen PRIMA (EU ENV 2007-1). Ce modèle permet d'étudier l'évolution des populations rurales sous l'effet des interactions spatiales et des dynamiques économiques locales.
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@techreport{PUB00036510, author = {Huet, S. and Dumoulin, N. and Deffuant, G. and Gargiulo, F. and Lenormand, M. and Baqueiro Espinosa, O. and Ternes, S.}, title = {Micro-simulation model of municipality network in the Auvergne case study }, title = {Modèle de micro-simulation d'un réseau de communes : étude de cas en Auvergne}, pages = {66}, pdf = {http://motive.cemagref.fr/_publication/PUB00036510.pdf}, year = {2012}, affiliation = {IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IAMO INSTITUTE OF AGRICULTURAL DEVELOPMENT IN CENTRAL AND EASTERN EUROPE LEIBNITZ DEU ; IAMO INSTITUTE OF AGRICULTURAL DEVELOPMENT IN CENTRAL AND EASTERN EUROPE LEIBNITZ DEU}, abstract = {How do European rural areas evolve? Some tend to decrease dramatically, as in the Netherlands or in the United Kingdom, where the urban areas tend to spread all over the country. Their population can also be drastically depleting through a large rural exodus, as observed in for instance France, Bulgaria or Croatia in the first part of the last Century. They can also keep steady population densities occupied in leisure services offered to urban people and agriculture with various proportions of inhabitants commuting to the cities for their work. Better understanding these evolutions is what the PRIMA simulation model presented in this report is interested in. / Ce document décrit un modèle de micro-simulation de communes développé dans le cadre du projet européen PRIMA (EU ENV 2007-1). Ce modèle permet d'étudier l'évolution des populations rurales sous l'effet des interactions spatiales et des dynamiques économiques locales.}, }
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N. Turpin, B. Hautdidier, R. Laplana, D. Kopeva, M. Raley, O. Baqueiro, G. Deffuant, G. Woltjer, B. Meyer, M. Njavro, L. Jelinek, G. Abrami, O. Aznar, O. Barreteau, I. Bezlepkina, A. Bouwman, R. Franic, G. Garrod, M. Gomez, Wander Jager, S. Huet, E. Kozáková, M. Lenormand, J.B. Marsat, M. Delin, E. Perret, K. Rodseth, E. Romstad, B. Šakic Bobic, F. Schaft, H. Talbot, Q. Zhang
Final Report D0.4, PRIMA collaborative project, EU 7th Framework Programme, contract no. 212345
2012
abs web bib

Facing structural change, European rural areas still fulfil multiple social, economic and ecological functions. Because of scale interplays and sustainability trade-offs, their future dynamics are still difficult to ascertain. In addition to the inherent difficulties of this undertaking, challenges in actual assessments also depend on external shocks to the economy at large or to particular regions, along with spillover effects among neighbouring regions. PRIMA proposes to improve knowledge in scaling down this assessment. It focuses on agriculture, forestry, tourism, and ecosystem services, with special attention to the structural effects of the European policies at municipality levels. The six case studies of PRIMA, conducted in Germany, United Kingdom, France, Croatia, Czech Republic, and Bulgaria, are important for two main reasons: they provide test cases for the PRIMA approaches, and they have influenced the development of the PRIMA approaches. These case studies have been chosen for their variety of rural dynamics and governance organisation. Because of the bottom-up governance of the European cohesion policy, a large variety has been observed in the priorities and measures, targeted to several pillars of sustainable development. This variety has been narrowed in a pre-modelling stage, where 2 groups of stakeholders were interviewed: those who can assist in scenario and model development (coming from the institutions which implement policy), and the actors who may be affected by the policy and hence whose related behavioural changes should be captured by the model framework. A conceptual model has then been developed. This model focuses on the population dynamics in rural municipalities and on the decision making behaviours observed. The conceptual micro-simulation model was successfully adapted to three of the study regions (France, United Kingdom and Germany). Additionally, the developed agent-based model was adapted for the United Kingdom region; this allowed studying the effects of social aspects that are not captured in the micro-simulation model. For validation purposes, a series of workshops were conducted on the case study areas. The orientation of these workshops depended on the availability of the models for the given case study area. The workshops promoted stakeholder learning about modelling. On the whole, participants recognised models as simplifications of reality. They found explanations about the model components comprehensible, and reacted fairly favourably to the idea of having such a decision-support tool available. However, the lack of good data at a low geographical scale in most case study areas was seen as a severe limitation. Beyond pathways for model revision, some methodological advances in the field of participatory modelling have been identified. Among these is making explicit the role of a model broker, the endorsement of which should improve the various interpretations of participants. Scenario development, though far in advance of their technical skills, has also proved an efficient tool to involve stakeholders in challenging a model. Further conceptual work was identified and undertaken concerning the design of methods to reconstruct commuting network for regions where data was unavailable, to calibrate models with several number of variables and of new approaches to dynamically derive services jobs availability. PRIMA also developed a conceptual work that includes the MAGNET (formerly LEITAP) model for downscaling from world level to the country level, and a downscaling tool from country level towards the NUTS2 level. An interface has been developed for easy downscaling of scenarios. Special attention has been paid to procedures to process data from Eurostat towards a database useful as input for the downscaling model. Last, we progressed towards recommendations enhancing the scope of IA methods, with a review of literature and extensive work between all workpackages.
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@techreport{PUB00035265, author = {Turpin, N. and Hautdidier, B. and Laplana, R. and Kopeva, D. and Raley, M. and Baqueiro, O. and Deffuant, G. and Woltjer, G. and Meyer, B. and Njavro, M. and Jelinek, L. and Abrami, G. and Aznar, O. and Barreteau, O. and Bezlepkina, I. and Bouwman, A. and Franic, R. and Garrod, G. and Gomez, M. and Wander Jager, and Huet, S. and Kozáková, E. and Lenormand, M. and Marsat, J.B. and Delin, M. and Perret, E. and Rodseth, K. and Romstad, E. and Šakic Bobic, B. and Schaft, F. and Talbot, H. and Zhang, Q.}, title = {Final Report D0.4, PRIMA collaborative project, EU 7th Framework Programme, contract no. 212345}, title = {Rapport final du projet européen PRIMA}, pages = {54}, url = {https://prima.cemagref.fr/}, cemadoc = {http://cemadoc.irstea.fr/cemoa/PUB00035265}, year = {2012}, affiliation = {IRSTEA CLERMONT FERRAND UMR METAFORT FRA ; IRSTEA BORDEAUX UR ADBX FRA ; IRSTEA BORDEAUX UR ADBX FRA ; UNWE SOFIA BGR ; UNEW NEWCASTLE UPON TYNE GBR ; INSTITUTE OF AGRICULTURAL DEVELOPMENT IN CENTRAL AND EASTERN DEU ; IRSTEA CLERMONT FERRAND UR LISC FRA ; WAGENINGEN UNIVERSITY NLD ; UNIVERSITY OF TECHNOLOGY DORTMUND DEU ; UNIVERSITE DE ZAGREB KRO ; UNIVERSITE DE ZAGREB KRO ; IRSTEA MONTPELLIER UR IRMO FRA ; IRSTEA CLERMONT FERRAND UMR METAFORT FRA ; IRSTEA MONTPELLIER IRMO ; LEI WAGENINGEN NLD ; - ; FACULTY OF AGRICULTURE AND TOURISM OF ZAGREB CRO ; CENTRE FOR RURAL ECONOMY SCHOOL OF AGRICULTURE, FOOD AND RURAL DEVELOPMENT NEWCASTLE UNIVERSITY GBR ; IRSTEA CLERMONT FERRAND UMR METAFORT FRA ; - ; IRSTEA CLERMONT FERRAND UR LISC FRA ; - ; IRSTEA CLERMONT FERRAND UR LISC FRA ; IRSTEA CLERMONT FERRAND UMR METAFORT FRA ; INSTITUTE OF ARGICULTURAL ECONOMICS AND INFORMATION CZR ; IRSTEA CLERMONT FERRAND UMR METAFORT FRA ; - ; UNIVERSITY OF NORWAY AAS NOR ; - ; - ; - ; -}, abstract = {Facing structural change, European rural areas still fulfil multiple social, economic and ecological functions. Because of scale interplays and sustainability trade-offs, their future dynamics are still difficult to ascertain. In addition to the inherent difficulties of this undertaking, challenges in actual assessments also depend on external shocks to the economy at large or to particular regions, along with spillover effects among neighbouring regions. PRIMA proposes to improve knowledge in scaling down this assessment. It focuses on agriculture, forestry, tourism, and ecosystem services, with special attention to the structural effects of the European policies at municipality levels. The six case studies of PRIMA, conducted in Germany, United Kingdom, France, Croatia, Czech Republic, and Bulgaria, are important for two main reasons: they provide test cases for the PRIMA approaches, and they have influenced the development of the PRIMA approaches. These case studies have been chosen for their variety of rural dynamics and governance organisation. Because of the bottom-up governance of the European cohesion policy, a large variety has been observed in the priorities and measures, targeted to several pillars of sustainable development. This variety has been narrowed in a pre-modelling stage, where 2 groups of stakeholders were interviewed: those who can assist in scenario and model development (coming from the institutions which implement policy), and the actors who may be affected by the policy and hence whose related behavioural changes should be captured by the model framework. A conceptual model has then been developed. This model focuses on the population dynamics in rural municipalities and on the decision making behaviours observed. The conceptual micro-simulation model was successfully adapted to three of the study regions (France, United Kingdom and Germany). Additionally, the developed agent-based model was adapted for the United Kingdom region; this allowed studying the effects of social aspects that are not captured in the micro-simulation model. For validation purposes, a series of workshops were conducted on the case study areas. The orientation of these workshops depended on the availability of the models for the given case study area. The workshops promoted stakeholder learning about modelling. On the whole, participants recognised models as simplifications of reality. They found explanations about the model components comprehensible, and reacted fairly favourably to the idea of having such a decision-support tool available. However, the lack of good data at a low geographical scale in most case study areas was seen as a severe limitation. Beyond pathways for model revision, some methodological advances in the field of participatory modelling have been identified. Among these is making explicit the role of a model broker, the endorsement of which should improve the various interpretations of participants. Scenario development, though far in advance of their technical skills, has also proved an efficient tool to involve stakeholders in challenging a model. Further conceptual work was identified and undertaken concerning the design of methods to reconstruct commuting network for regions where data was unavailable, to calibrate models with several number of variables and of new approaches to dynamically derive services jobs availability. PRIMA also developed a conceptual work that includes the MAGNET (formerly LEITAP) model for downscaling from world level to the country level, and a downscaling tool from country level towards the NUTS2 level. An interface has been developed for easy downscaling of scenarios. Special attention has been paid to procedures to process data from Eurostat towards a database useful as input for the downscaling model. Last, we progressed towards recommendations enhancing the scope of IA methods, with a review of literature and extensive work between all workpackages.}, }
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S. Huet, G. Deffuant
Calcul de l'impact économique de la conversion à l'agriculture biologique : projet IMAGES, modèle Allier Conversion à l'agriculture biologique
2001
abs web bib

The objective was to simulate the calculation that farmers from Allier department can make when they have to take a decision about using or not an environmental measure. Farms diversity has been taken into account. The calculation was based on three steps: identification of available data and possible variation of Images model parameters - modelling of the calculation - selection of parameters to be used for impact calculation by Images model. / Ce travail a pour objectif de définir un calcul d'impact économique de la conversion à l'agriculture biologique pour les exploitations agricoles du département de l'Allier. Il s'inscrit dans le cadre du modèle élaboré dans le projet IMAGES, qui simule les processus de décision des agriculteurs confrontés au choix d'adopter ou non une mesure agri-environnementale. L'objectif est donc ici de simuler le calcul que peuvent faire les agriculteurs au moment de la décision, c'est-à-dire en tenant compte de nombreuses incertitudes. Le modèle IMAGES a pour objectifs de simuler les décisions de l'ensemble de la population des agriculteurs de l'Allier, en prenant au maximum en compte la diversité des exploitations. Le calcul d'impact économique de la conversion doit donc être applicable avec le maximum de réalisme à l'ensemble de cette diversité. Ce type de calcul n'existe pas dans la littérature. En effet, il n'existe pour le moment aucune référence solide, applicable dans tous les cas de figure et admise par tous, qui permette de mesurer les rendements en agriculture biologique. Ainsi, pour réaliser un tel calcul, trois grandes étapes sont nécessaires : - identification des données disponibles et des plages de variations possibles des paramètres du modèle - modélisation du calcul réalisé par le technicien de la Chambre d'Agriculture de l'Allier - exploration des paramètres du modèle et sélection de jeux de paramètres à utiliser pour le calcul d'impact du modèle Images par élimination des résultats paraissant aberrants. L'innovation principale de ce travail est de proposer des évaluations du potentiel de l'agriculture biologique en Auvergne et dans l'Allier en terme d'exploitations économiquement intéressées à se convertir (nombre d'exploitations, caractéristiques, ...).
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@techreport{PUB00009543, author = {Huet, S. and Deffuant, G.}, title = {Calcul de l'impact économique de la conversion à l'agriculture biologique : projet IMAGES, modèle Allier Conversion à l'agriculture biologique}, title = {Effect calculation of conversion to biologic agriculture on economy: IMAGES project, Allier Department model Conversion to biologic agriculture}, pages = {77}, url = {http://cemadoc.irstea.fr/cemoa/PUB00009543}, year = {2001}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC}, number = {01/0399 ; IAS 78}, abstract = {The objective was to simulate the calculation that farmers from Allier department can make when they have to take a decision about using or not an environmental measure. Farms diversity has been taken into account. The calculation was based on three steps: identification of available data and possible variation of Images model parameters - modelling of the calculation - selection of parameters to be used for impact calculation by Images model. / Ce travail a pour objectif de définir un calcul d'impact économique de la conversion à l'agriculture biologique pour les exploitations agricoles du département de l'Allier. Il s'inscrit dans le cadre du modèle élaboré dans le projet IMAGES, qui simule les processus de décision des agriculteurs confrontés au choix d'adopter ou non une mesure agri-environnementale. L'objectif est donc ici de simuler le calcul que peuvent faire les agriculteurs au moment de la décision, c'est-à-dire en tenant compte de nombreuses incertitudes. Le modèle IMAGES a pour objectifs de simuler les décisions de l'ensemble de la population des agriculteurs de l'Allier, en prenant au maximum en compte la diversité des exploitations. Le calcul d'impact économique de la conversion doit donc être applicable avec le maximum de réalisme à l'ensemble de cette diversité. Ce type de calcul n'existe pas dans la littérature. En effet, il n'existe pour le moment aucune référence solide, applicable dans tous les cas de figure et admise par tous, qui permette de mesurer les rendements en agriculture biologique. Ainsi, pour réaliser un tel calcul, trois grandes étapes sont nécessaires : - identification des données disponibles et des plages de variations possibles des paramètres du modèle - modélisation du calcul réalisé par le technicien de la Chambre d'Agriculture de l'Allier - exploration des paramètres du modèle et sélection de jeux de paramètres à utiliser pour le calcul d'impact du modèle Images par élimination des résultats paraissant aberrants. L'innovation principale de ce travail est de proposer des évaluations du potentiel de l'agriculture biologique en Auvergne et dans l'Allier en terme d'exploitations économiquement intéressées à se convertir (nombre d'exploitations, caractéristiques, ...).}, }
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G. Deffuant, F. Amblard, S. Huet, S. Bernard, N. Ferrand, J.P. Bousset, G. Amon, J. Henriot
Projet européen IMAGES :Simulation de l'évolution des conversions à l'agriculture biologique dans le département de l'Allier entre 1994 et 1999 par un modèle multi-agents Rapport d'avancement du cas Allier
2000
abs web bib

Nous présentons un modèle permettant de simuler l'évolution des conversions à l'agriculture biologique dans le département de l'Allier entre 1994 et 1999. Le modèle se nourrit d'enquêtes réalisées sur le terrain ainsi que de données statistiques diverses. Il se fonde sur une reconstitution valide statistiquement de la population d'agriculteurs du département et leur localisation par commune. Les réseaux sociaux des agriculteurs (constitué d'autres agriculteurs et d'acteurs institutionnels) sont considérés dans le modèle. La décision de conversion est modélisée comme le résultat d'un processus comprenant plusieurs étapes. Intéractions sociales et calculs économiques se mêlent étroitement dans ce processus. L'objectf du modèle à terme est de fournir des tendances prospectives sur les évolutions futures des conversions, en fonction d'hypothèses sur l'évolution du contexte économique et politique.
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@techreport{PUB00009312, author = {Deffuant, G. and Amblard, F. and Huet, S. and Bernard, S. and Ferrand, N. and Bousset, J.P. and Amon, G. and Henriot, J.}, title = {Projet européen IMAGES :Simulation de l'évolution des conversions à l'agriculture biologique dans le département de l'Allier entre 1994 et 1999 par un modèle multi-agents Rapport d'avancement du cas Allier}, pages = {21}, url = {http://cemadoc.irstea.fr/cemoa/PUB00009312}, year = {2000}, affiliation = {CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND LISC ; CEMAGREF CLERMONT FERRAND DFCF ; CEMAGREF CLERMONT FERRAND DFCF ; CEMAGREF CLERMONT FERRAND DFCF}, number = {00/0843}, abstract = {Nous présentons un modèle permettant de simuler l'évolution des conversions à l'agriculture biologique dans le département de l'Allier entre 1994 et 1999. Le modèle se nourrit d'enquêtes réalisées sur le terrain ainsi que de données statistiques diverses. Il se fonde sur une reconstitution valide statistiquement de la population d'agriculteurs du département et leur localisation par commune. Les réseaux sociaux des agriculteurs (constitué d'autres agriculteurs et d'acteurs institutionnels) sont considérés dans le modèle. La décision de conversion est modélisée comme le résultat d'un processus comprenant plusieurs étapes. Intéractions sociales et calculs économiques se mêlent étroitement dans ce processus. L'objectf du modèle à terme est de fournir des tendances prospectives sur les évolutions futures des conversions, en fonction d'hypothèses sur l'évolution du contexte économique et politique.}, }
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LISC