Issue
EPL
Volume 86, Number 2, April 2009
Article Number 28005
Number of page(s) 6
Section Interdisciplinary Physics and Related Areas of Science and Technology
DOI http://dx.doi.org/10.1209/0295-5075/86/28005
Published online 04 May 2009
EPL, 86 (2009) 28005
DOI: 10.1209/0295-5075/86/28005

Filtering of complex systems using overlapping tree networks

A. Garas and P. Argyrakis

Department of Physics, University of Thessaloniki - 54124 Thessaloniki, Greece, EU

agara@physics.auth.gr
panos@physics.auth.gr

received 16 December 2008; accepted in final form 20 March 2009; published April 2009
published online 4 May 2009

Abstract
We introduce a technique that is capable to filter out information from complex systems, by mapping them to networks, and extracting a subgraph with the strongest links. This idea is based on the Minimum Spanning Tree, and it can be applied to sets of graphs that have as links different sets of interactions among the system's elements, which are described as network nodes. It can also be applied to correlation-based graphs, where the links are weighted and represent the correlation strength between all pairs of nodes. We applied this method to the European scientific collaboration network, which is composed of all the projects supported by the European Framework Program FP6, and also to the correlation-based network of the 100 highest capitalized stocks traded in the New York Stock Exchange. For both cases we identified meaningful structures, such as a strongly interconnected community of countries that play an important role in the collaboration network, and clusters of stocks belonging to different sectors of economic activity, which gives significant information about the investigated systems.

PACS
89.75.-k - Complex systems.
89.65.-s - Social and economic systems.
89.90.+n - Other topics in areas of applied and interdisciplinary physics.

© EPLA 2009