Ego-betweenness centrality in link streams

International audienceThe ability of a node to relay information in a network is often measured using betweenness centrality. In order to take into account the fact that the role of the nodes vary through time, several adaptations of this concept have been proposed to time-evolving networks. However, these definitions are demanding in terms of computational cost, as they call for the computation of time-ordered paths. We propose a definition of centrality in link streams which is node-centric, in the sense that we only take into account the direct neighbors of a node to compute its centrality. This restriction allows to carry out the computation in a shorter time compared to a case where any couple of nodes in the network should be considered. Tests on empirical data show that this measure is relatively highly correlated to the number of times a node would relay information in a flooding process. We suggest that this is a good indication that this measurement can be of use in practical contexts where a node has a limited knowledge of its environment, such as routing protocols in delay tolerant networks

Transnational Activism in Support of National Protest: Questions of Identity and Organization

This article considers the question of whether transnational activism supporting national protest attains a cohesive collective identity on social media whilst organizationally remaining localized. It examines a corpus of social media data collected in the course of two months of rolling protests in 2013 against the largest proposed open-cast gold mine at Roşia Montană, Romania, which echoed among Romanian expatriates. A network text analysis of the data supplemented with interview findings revealed concerns with protest logistics as common across the transnational networks of protest localities on both Facebook and Twitter, a finding that testified to the coordinated character of the protests. On the other hand, collective identity emerged as the fruit of attempts to surmount localized protest experiences of geographically disparate but civically-minded social media users

A study of the influence of network structural embeddedness on organization innovativeness

This paper explores the impact of network structural embeddedness of an organization on its innovativeness. Based on a survey of 104 organizations in the medium and high technology sectors in Saudi Arabia, we explored the relationships between different network characteristics (i.e. network density, centrality) and organization’s type and degree of innovativeness. Using a logistic regression analysis, the study finds that there is a positive and significant relationship between organization’s network density and centrality with both product innovation and process innovation. Additionally, the study investigated the influence of network characteristics on the degree of novelty of innovation (i.e. radical innovation). The findings reveal that having a central network position in terms of betweenness and degree centrality have a positive and significant relationship with novel innovation. However, the study results show insignificant relationship between network density and novel innovation

Supporting decision-making for sustainable development: Social Network Analyses and Social Network Theory as a tool for policy advice

As of late, scholars of diverse disciplines observe the growing importance of social networks for sustainable development processes. However, in the social sciences concepts of Social Network Analysis (SNA) have been frequently used metaphorically for another purpose (Hwang and Moon 2009, 7). At the same time, metaphorical uses of models can be harmful. “Relying on metaphors as the foundation for policy advice can lead to results substantially different from those presumed to be likely” (Ostrom 2010). This paper argues that empirical techniques of SNA can support evidence-based decision making and policy advice. On this note, results of a theoretically based empirical study are introduced that illustrate why and how SNA provides innovative tools to foster learning processes and synergy effects, bring together key resources and technological know-how and promote advancements and the diffusion of innovative ideas. Furthermore, it is argued that SNA helps to interpret existing networks and to identify innovation potentials in order to generate new information and to reveal new options for further developments