Network theory

About: Network theory is a research topic. Over the lifetime, 2257 publications have been published within this topic receiving 109864 citations.

Entropy-based approach to missing-links prediction

Abstract: Link-prediction is an active research field within network theory, aiming at uncovering missing connections or predicting the emergence of future relationships from the observed network structure. This paper represents our contribution to the stream of research concerning missing links prediction. Here, we propose an entropy-based method to predict a given percentage of missing links, by identifying them with the most probable non-observed ones. The probability coefficients are computed by solving opportunely defined null-models over the accessible network structure. Upon comparing our likelihood-based, local method with the most popular algorithms over a set of economic, financial and food networks, we find ours to perform best, as pointed out by a number of statistical indicators (e.g. the precision, the area under the ROC curve, etc.). Moreover, the entropy-based formalism adopted in the present paper allows us to straightforwardly extend the link-prediction exercise to directed networks as well, thus overcoming one of the main limitations of current algorithms. The higher accuracy achievable by employing these methods - together with their larger flexibility - makes them strong competitors of available link-prediction algorithms.

Global vs local modularity for network community detection.

Abstract: Community structures are ubiquitous in various complex networks, implying that the networks commonly be composed of groups of nodes with more internal links and less external links. As an important topic in network theory, community detection is of importance for understanding the structure and function of the networks. Optimizing statistical measures for community structures is one of most popular strategies for community detection in complex networks. In the paper, by using a type of self-loop rescaling strategy, we introduced a set of global modularity functions and a set of local modularity functions for community detection in networks, which are optimized by a kind of the self-consistent method. We carefully compared and analyzed the behaviors of the modularity-based methods in community detection, and confirmed the superiority of the local modularity for detecting community structures on large-size and heterogeneous networks. The local modularity can more quickly eliminate the first-type limit of modularity, and can eliminate or alleviate the second-type limit of modularity in networks, because of the use of the local information in networks. Moreover, we tested the methods in real networks. Finally, we expect the research can provide useful insight into the problem of community detection in complex networks.

Wanted: A Good Network Theory of Policy Making 1

Abstract: In the policy literature, networks have now for some time been named as an important governance mechanism. From the level of global governance, European integration, and sectoral policy networks to regional arrangements, policy networks are seen as a way to integrate differentiated actor systems and to adjust to problems that cannot be tackled by existing formal institutional configurations. Numerous empirical cases of policy networks have been produced and the development and structures of policy networks have been explained, but what seems missing is theory building on the role of networks in policy making. Therefore, in the paper we will first introduce Wallace’s model for theory development. Secondly, we will apply this model and evaluate the literature according to the question what has been achieved so far. We will then suggest what steps should be taken next in order to make some progress towards the development of a network theory of policy making.

Power Indices of Influence Games and New Centrality Measures for Agent Societies and Social Networks

Abstract: We propose as centrality measures for social networks two classical power indices, Banzhaf and Shapley-Shubik, and two new measures, effort and satisfaction, related to the spread of influence process that emerge from the subjacent influence game. We perform a comparison of these measures with three well known centrality measures, degree, closeness and betweenness, applied to three simple social networks.

The Logic Model as a Tool for Developing a Network Performance Measurement System

Abstract: Performance measurement and networked collaboration are each important trends in public management. Research and practice on these two issues have largely proceeded on separate tracks. A logic model framework offers a way to conceptualize network coordination and performance by making explicit the hypothesized relations between network processes and outcomes. Hatry's (2006) logic model approach is used as a heuristic tool toward developing measurable indicators for network planning, implementation, and evaluation. This article provides a theoretical rationale for bridging the logic model concept with emergent network theory about outcomes-focused network processes. Several illustrative examples depict the application of logic modeling to three elements of a network performance measurement system: planning, implementation, and evaluation. The article discusses the implications of the logic model approach as a tool for developing, managing, and assessing the performance outcomes of collaborative and network...