Deroïan

Publications

Formation of social networks and diffusion of innovationsJournal articleFrédéric Deroian, Research Policy, Volume 31, Issue 5, pp. 835-846, 2002

No abstract is available for this item.

Morphogenesis Of Social Networks And Coexistence Of TechnologiesJournal articleFrédéric Deroian, Economics of Innovation and New Technology, Volume 10, Issue 6, pp. 427-448, 2001

The aim of the article is to relate the formation of influence networks to the coexistence of technologies in the long run. In the spirit of Plouraboue et al. (1998), we postulate that potential adopters of a technology are situated in a social network. In our model, initial relations are partly negative and all the expected utilities are revised in parallel. In the case of an exogenous network, opinions can fluctuate endlessly. When agents reallocate their relationships, this reinforces trust in agents whose opinion is close to theirs. As a result of this process, the network stabilizes in the long run, generating diversity in expected utilities.

Lock-out in Social NetworksBook chapterFrédéric Deroian, In: Economics with Heterogeneous Interacting Agents, Alan Kirman and Jean-Benoît Zimmermann (Eds.), 2001, Volume 503, pp. 57-72, Springer Berlin Heidelberg, 2001

We introduce negative relationships in a network of social influence whose agents cope with a binary opinion concerning two competing standards, and we explore the possible collective dynamics. A weak proportion of anticonformism leads to well known phenomenon of lock-in (collective agreement uppon one given opinion). Too much anticonformism generates persistent instability in individual opinions about technological standards. Now, we point out that an optimal dose of anticonformism can originate lock-outs: a minimal amount is necessary to depart from homogenous behaviors, but too much would prevent the rest of the society from reaching the opinions of anticonformists, and achieve the lock-out. Hence, our interaction-ist analysis points out specific conditions of demand as a possible reason for changing consumer behaviors in a context of standardization.

Cumul d'influence et réseaux sociaux : une application aux processus de diffusion de l'innovationJournal articleJean-Benoît Zimmermann and Frédéric Deroian, Revue d'Économie Industrielle, Volume 96, Issue 1, pp. 7-27, 2001

[eng] While adopting an approach of innovation diffusion in terms of interacting agents, we emphasise the role of cumulated influence in the context of social networks. We first introduce a cumulative effect in the classical epidemic model which involves a slower starting phase followed by a more pronounced acceleration phase. We then show that the topology of the network affects both equilibrium selection as well the pace of diffusion. Hence the nature of uncertainty characterising the diffusion process is affected by the structure of the network and the distribution of initial adopters.
[fre] En nous situant dans le cadre des modèles interactionnistes de diffusion de l'innovation, nous mettons en évidence le rôle joué par la notion de cumul d'influence dans un contexte de réseaux sociaux. Nous introduisons d'abord un effet de cumul dans le modèle épidémique classique se traduisant par un démarrage plus lent et une phase d'accélération plus marquée. Nous montrons ensuite que la topologie du réseau peut intervenir aussi bien dans la détermination de l'équilibre atteint que dans celle de la vitesse de diffusion. L'issue de la diffusion est ainsi marquée d'une forme d'incertitude qui confère un rôle essentiel à la structure du réseau et à la distribution des adopteurs initiaux.