7,476 research outputs found

    Mainstreaming Gender Into Project Cycle Management in the Fisheries Sector

    Get PDF
    This manual has been prepared to facilitate gender analysis and project planning in fisheries development projects. It is intended to be a toolkit to help project managers and implementing counterparts (such as extensionists, government and non-government field workers, and private- and public-sector development consultants, community organizers and leaders of local groups), to facilitate the integration of gender issues into the project cycle

    Dynamical properties of model communication networks

    Get PDF
    We study the dynamical properties of a collection of models for communication processes, characterized by a single parameter ξ\xi representing the relation between information load of the nodes and its ability to deliver this information. The critical transition to congestion reported so far occurs only for ξ=1\xi=1. This case is well analyzed for different network topologies. We focus of the properties of the order parameter, the susceptibility and the time correlations when approaching the critical point. For ξ<1\xi<1 no transition to congestion is observed but it remains a cross-over from a low-density to a high-density state. For ξ>1\xi>1 the transition to congestion is discontinuous and congestion nuclei arise.Comment: 8 pages, 8 figure

    Optimal map of the modular structure of complex networks

    Full text link
    Modular structure is pervasive in many complex networks of interactions observed in natural, social and technological sciences. Its study sheds light on the relation between the structure and function of complex systems. Generally speaking, modules are islands of highly connected nodes separated by a relatively small number of links. Every module can have contributions of links from any node in the network. The challenge is to disentangle these contributions to understand how the modular structure is built. The main problem is that the analysis of a certain partition into modules involves, in principle, as many data as number of modules times number of nodes. To confront this challenge, here we first define the contribution matrix, the mathematical object containing all the information about the partition of interest, and after, we use a Truncated Singular Value Decomposition to extract the best representation of this matrix in a plane. The analysis of this projection allow us to scrutinize the skeleton of the modular structure, revealing the structure of individual modules and their interrelations.Comment: 21 pages, 10 figure

    Modeling Structure and Resilience of the Dark Network

    Full text link
    While the statistical and resilience properties of the Internet are no more changing significantly across time, the Darknet, a network devoted to keep anonymous its traffic, still experiences rapid changes to improve the security of its users. Here, we study the structure of the Darknet and we find that its topology is rather peculiar, being characterized by non-homogenous distribution of connections -- typical of scale-free networks --, very short path lengths and high clustering -- typical of small-world networks -- and lack of a core of highly connected nodes. We propose a model to reproduce such features, demonstrating that the mechanisms used to improve cyber-security are responsible for the observed topology. Unexpectedly, we reveal that its peculiar structure makes the Darknet much more resilient than the Internet -- used as a benchmark for comparison at a descriptive level -- to random failures, targeted attacks and cascade failures, as a result of adaptive changes in response to the attempts of dismantling the network across time.Comment: 8 pages, 5 figure

    Motif-based communities in complex networks

    Full text link
    Community definitions usually focus on edges, inside and between the communities. However, the high density of edges within a community determines correlations between nodes going beyond nearest-neighbours, and which are indicated by the presence of motifs. We show how motifs can be used to define general classes of nodes, including communities, by extending the mathematical expression of Newman-Girvan modularity. We construct then a general framework and apply it to some synthetic and real networks

    On Self-Organized Criticality and Synchronization in Lattice Models of Coupled Dynamical Systems

    Full text link
    Lattice models of coupled dynamical systems lead to a variety of complex behaviors. Between the individual motion of independent units and the collective behavior of members of a population evolving synchronously, there exist more complicated attractors. In some cases, these states are identified with self-organized critical phenomena. In other situations, with clusterization or phase-locking. The conditions leading to such different behaviors in models of integrate-and-fire oscillators and stick-slip processes are reviewed.Comment: 41 pages. Plain LaTeX. Style included in main file. To appear as an invited review in Int. J. Modern Physics B. Needs eps
    corecore