Artículos con la etiqueta ‘redes’

Control centrality and hierarchical structure in complex networks

Por • 15 jun, 2012 • Category: sociologia

We introduce the concept of control centrality to quantify the ability of a single node to control a directed weighted network. We calculate the distribution of control centrality for several real networks and find that it is mainly determined by the network’s degree distribution. We rigorously prove that in a directed network without loops the control centrality of a node is uniquely determined by its layer index or topological position in the underlying hierarchical structure of the network. Inspired by the deep relation between control centrality and hierarchical structure in a general directed network, we design an efficient attack strategy against the controllability of malicious networks.



Network structure of inter-industry flows

Por • 23 abr, 2012 • Category: Economía

We study the structure of inter-industry relationships using networks of money flows between industries in 20 national economies. We find these networks vary around a typical structure characterized by a Weibull link weight distribution, exponential industry size distribution, and a common community structure. The community structure is hierarchical, with the top level of the hierarchy comprising five industry communities: food industries, chemical industries, manufacturing industries, service industries, and extraction industries.



Evolutionary Events in a Mathematical Sciences Research Collaboration Network

Por • 4 abr, 2012 • Category: sociologia

Collaboration is key to scientific research, and increasingly to mathematics. This paper contains a longitudinal investigation of mathematics collaboration and publishing using the proprietary database Mathematical Reviews, maintained by the American Mathematical Society. The database contains publications by several hundred thousand researchers over 25 years. Mathematical scientists became more interconnected, collaborative, and interdisciplinary over this interval, and twice the network experienced dramatic structural shifts. These events are examined and possible external factors are discussed. Smaller subject-specific subnetworks exhibit behavior that provides insight into the aggregate dynamics. The data are available upon request to the Executive Director of the AMS.



Ranking and clustering countries and their products; a network analysis

Por • 21 ago, 2011 • Category: Opinion

In this paper we analyze the network of countries and products from UN data on country production. We define the country-country and product-product networks and we introduce a novel method of community detection based on elements similarity. As a result we find that country clustering reveals unexpected socio-geographic links among the most competing countries.