Knowledge flows and the geography of networks. A strategic model of small worlds formation.

This paper aims to demonstrate that the strategic approach of network formation can generate networks that share the main structural properties of most real social networks. We introduce a spatialized variation of the Connections model (Jackson and Wolinski, 1996) in which agents balance the benefits of forming links resulting from imperfect knowledge flows through bonds against their costs which increase with geographic distance. We show that, for intermediary levels of knowledge transferability, our time-inhomogeneous process selects networks which exhibit high clustering, short average distances and, when the costs of link formation are normally distributed across agents, skewed degree distributions.Strategic network formation ; Time-inhomogeneous process ; Knowledge flows ; Small worlds ; Monte Carlo simulations.

A strategic model of complex networks formation.

This paper introduces a spatialized variation of the Connections model of Jackson and Wolinski (1996). Agents benefit from their direct and indirect connections in a communication network. They are arranged on a circle and bear costs for maintaining direct connections which are linearly increasing with geographic distance. In a dynamic setting, this model is shown to generate networks that exhibit the small world properties shared by many real social and economic networks.Strategic Network Formation, Pairwise Stability, Small World, Monte Carlo.

Coordination failures in network formation.

In this paper, we make an exploratory use of numerical techniques (genetic algorithms and Monte Carlo simulations) to compute efficient and emergent networks in a spatialized version of the connections model of Jackson and Wolinski (1996). This approach allows us to observe and discuss the coordination failures that arise in a strategic network formation context with link-mediated positive externalities to connections and geographically based connection costs. Our results highlight that, depending on the strength of the externalities, emergent and efficient networks may share several structural properties. Nevertheless, emergent networks have too few local and distant connections and are also too less “coordinated” around some central agents than they should.Strategic Network Formation; Efficiency; Stability; Coordination; Small Worlds; Genetic Algorithms; Monte Carlo Simulations.

A STUDY OF SCIENCE-INDUSTRY COLLABORATIVE PATTERNS IN A LARGE EUROPEAN UNIVERSITY.

This paper analyses the modalities according to which a large European university collaborates with firms by exploring its relational portfolio. We address this issue by exploiting a database listing more than 1000 firms having collaborated with the University Louis Pasteur between 1990 and 2002. First, using multi-correspondence analysis, we derive a four-classes typology of collaborative behaviours, each of them presenting a strong internal coherence. We obtain four distinct collaboration patterms, for which the frequency of interactions and the exclusive vs. open character of the relationships are discriminating features. Second, using a multinomial logit estimation, we show how this diversity is connected to some individual attributes of the firms: size, legal status, industrial sector and geographic distance from the public partner.Science-industry collaborations; Typology; Industrial collaboration patterns.

Self-Organizing Innovation Networks: When do Small Worlds Emerge?

In this paper, we present a model of 'collective innovation' built upon the network formation formalism. In our model, agents localized on a circle benefit from knowledge flows from other agents with whom they are directly or indirectly connected. They support costs for direct connections which are linearly increasing with geographic distance. The dynamic process of network formation exhibits prefeRential meeting for close agents (in the relational network and in the geographic metrics). We show how the set of stochastically stable networks selected in the long run is affected by the degree of knowledge transferability. We find critical values of this parameter for which stable \"small world\" networks are dynamically selected.Network Formation, Stochastic Stability, Preferential Meeting, Self-Organization,

Knowledge flows and the geography of networks: a strategic model of small world formation

"This paper aims to demonstrate that the strategic approach to link formation can generate networks that share some of the main structural properties of most real social networks. For this purpose, we introduce a spatialized variation of the Connections model (Jackson and Wolinsky 1996) to describe the strategic formation of links by agents who balance the benefits of forming links resulting from imperfect knowledge flows against their costs, which increase with geographic distance. We show, for intermediate levels of knowledge transferability, clustering occurs in geographical space and a few agents sustain distant connections. Such networks exhibit the small world property (high clustering and short average relational distances). When the costs of link formation are normally distributed across agents, asymmetric degree distributions are also obtained." [author's abstract

Twenty years of evolution in French secondary school science textbooks

Textbooks are highly structured objects, which are easily distinguished from other types of publications such as popular science books or academic works. This recognisable shape results from section-specific formatting, and layout standardisation. Yet these structures change over time and differ according to school disciplines.Our aim is to understand textbooks (specific resources) in themselves and grasp their evolution dynamics. Our approach here is to examine textbooks in both descriptive and analytical ways, using a comparative approach, and focusing on science high school textbooks, over a period of 20 years. The main questions steering our analysis are: What are the basic components of these textbooks? How to identify elements that are common to various school subjects or stable over time? What trends seem to be emerging? We have sought to highlight – via an analysis of school programme changes – some shared features that shed light on the directions that these school subjects and their supporting resources seem to take

Inefficiencies in a model of spatial networks formation with positive externalities

In this paper, we make an exploratory use of computational techniques (genetic algorithms and Monte Carlo simulations) to compute efficient and emergent networks in a spatialized version of the connections model of Jackson and Wolinski (Jackson, M.O., Wolinski, A., 1996. A strategic model of social and economic networks. Journal of Economic Theory 71, 44–74). This approach allows us to observe and discuss inefficiencies that arise in a strategic network formation context with imperfectly link-mediated positive externalities to connections and spatial link costs. Our results highlight that, depending on the strength of the externalities, emergent and efficient networks may share several structural properties. Nevertheless, emergent networks are insufficiently dense and should be more structured around central agents

L’illusion de la verve surréaliste dans Capitale de la douleur

Capitale de la douleur recourt à certains codes de la verve surréaliste, notamment par la mise en scène de l’émergence spontanée de la parole, ainsi que par le recours à des marques textuelles. Parmi celles-ci, certaines, syntaxiques, signalent la spontanéité et l’abondance d’une parole profuse, non soumise au contrôle de la raison. D’autres, liées aux images, reproduisent le flot originel de la parole et marquent la fantaisie qui naît de la dictée de l’inconscient. Mais la verve y est une « illusion », selon les mots de Breton dans le premier Manifeste, car Éluard joue de ces codes, il les détourne, parfois les subvertit ou y recourt pour égarer le lecteur

The evolution of the spatial digital divide: From internet adoption to internet use by french industrial firms

In this paper, we concentrate on different aspects of the « spatial digital divide » and seek to answer three questions : Are there still spatial inequalities in the adoption of these technologies ? Is there a so-called “second level” geographical divide characterized by important differences in the intensity of Internet use between firms that have adopted these tools? Do the appropriation processes and logic of diffusion of ICT adopters vary according to the type of area in which they are located (urban vs. rural areas)? To answer these questions we have constructed an original model of technological diffusion (of the type developed by Battisti and Stoneman, 2005) that merges two types of models: those that concentrate on epidemic effects, and the so-called equilibrium models that model the decision to adopt new technologies as the result of an economic calculation by firms, which depends on their internal characteristics and those of their competitive, industrial and local environment. This model uses data drawn from a recent national survey (“ICT and e-commerce” 2002). One of the main results is that, for a given size and sector, although there no longer are spatial inequalities in terms of ICT adoption in France, there are still important inequalities in firms’ processes of ICT appropriation and use.Internet, inter-firm and intra-firm diffusion, rank and epidemic effects, agglomeration effects, spatial inequalities