Physica A 346 (2005) 75–81 Networks: structure, function and optimisation Neelima Gupte à , Brajendra K. Singh 1 , T.M. Janaki Department of Physics, IIT Madras, Chennai 600036, India Available online 17 September 2004 Abstract Recent studies have shown that the structure and connectivity properties of networks have important consequences for their function and efficiency. It is therefore useful to ask whether these properties can be exploited to enhance the performance and efficiency of networks. We examine this question in two specific contexts, the load-bearing properties of a branching hierarchical network, and jamming and congestion in a two-dimensional communication network. We show that the capacity and performance of these networks can be enormously enhanced by judicious manipulation of connectivity properties. We discuss the relevance of these results to the general context of information spread processes on networks. r 2004 Elsevier B.V. All rights reserved. PACS: 89.75.Hc Keywords: Networks; Performance; Efficiency; Connectivity 1. Introduction The study of networks has been a topic of vigorous recent interest. A network consists of nodes plus links between nodes. Each node may be capable of some function and may have some capacity. Power grids, the internet, traffic networks, and telephone networks constitute examples of engineered networks, whereas ARTICLE IN PRESS www.elsevier.com/locate/physa 0378-4371/$-see front matter r 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.physa.2004.08.052 à Corresponding author. E-mail address: gupte@chaos.iitm.ernet.in (N. Gupte). 1 Present address: P611, Laboratory of Statistical and Computational Physics, Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, ROC.