1,101,286 research outputs found
A theory on power in networks
The eigenvector centrality equation is a successful
compromise between simplicity and expressivity. It claims that central actors
are those connected with central others. For at least 70 years, this equation
has been explored in disparate contexts, including econometrics, sociometry,
bibliometrics, Web information retrieval, and network science. We propose an
equally elegant counterpart: the power equation , where
is the vector whose entries are the reciprocal of those of . It
asserts that power is in the hands of those connected with powerless others. It
is meaningful, for instance, in bargaining situations, where it is advantageous
to be connected to those who have few options. We tell the parallel, mostly
unexplored story of this intriguing equation
Failure and avalanches in complex networks
We study the size distribution of power blackouts for the Norwegian and North
American power grids. We find that for both systems the size distribution
follows power laws with exponents and
respectively. We then present a model with global redistribution of the load
when a link in the system fails which reproduces the power law from the
Norwegian power grid if the simulation are carried out on the Norwegian
high-voltage power grid. The model is also applied to regular and irregular
networks and give power laws with exponents for the regular
networks and for the irregular networks. A presented mean field
theory is in good agreement with these numerical results.Comment: Added new references and some minor extentions on request from
referee. Changed figure order. Added journal re
Diffusion Processes on Power-Law Small-World Networks
We consider diffusion processes on power-law small-world networks in
different dimensions. In one dimension, we find a rich phase diagram, with
different transient and recurrent phases, including a critical line with
continuously varying exponents. The results were obtained using self-consistent
perturbation theory and can also be understood in terms of a scaling theory,
which provides a general framework for understanding processes on small-world
networks with different distributions of long-range links.Comment: 4 pages, 3 figures, added references, modified Fig. 2 with added data
(PRL, in press
Network robustness and fragility: Percolation on random graphs
Recent work on the internet, social networks, and the power grid has
addressed the resilience of these networks to either random or targeted
deletion of network nodes. Such deletions include, for example, the failure of
internet routers or power transmission lines. Percolation models on random
graphs provide a simple representation of this process, but have typically been
limited to graphs with Poisson degree distribution at their vertices. Such
graphs are quite unlike real world networks, which often possess power-law or
other highly skewed degree distributions. In this paper we study percolation on
graphs with completely general degree distribution, giving exact solutions for
a variety of cases, including site percolation, bond percolation, and models in
which occupation probabilities depend on vertex degree. We discuss the
application of our theory to the understanding of network resilience.Comment: 4 pages, 2 figure
Transmission of packets on a hierarchical network: Avalanches, statistics and explosive percolation
We discuss transport on load bearing branching hierarchical networks which
can model diverse systems which can serve as models of river networks, computer
networks, respiratory networks and granular media. We study avalanche
transmissions and directed percolation on these networks, and on the V lattice,
i.e., the strongest realization of the lattice. We find that typical
realizations of the lattice show multimodal distributions for the avalanche
transmissions, and a second order transition for directed percolation. On the
other hand, the V lattice shows power - law behavior for avalanche
transmissions, and a first order (explosive) transition to percolation. The V
lattice is thus the critical case of hierarchical networks. We note that small
perturbations to the V lattice destroy the power-law behavior of the
distributions, and the first order nature of the percolation. We discuss the
implications of our results.Comment: 10 Pages, 11 Figures, Published in (Chapter 17) International
Conference on Theory and Application in Nonlinear Dynamics (ICAND 2012),
Understanding Complex System
A Synthetic Theory of Political Sociology: Bringing Social Networks and Power Dependence to Power Resources Theory in City Politics
It is well established that power is connected to networks, yet structural theories of power in network analysis fail to satisfy political sociologists. Centrality is generally put forward as a measure of power, but this is not enough for political sociology. This article puts forward a theory of power that brings power resources and power dependency theory to the study of social networks concerning political coalitions in an urban polity. Within this theory of power resources, we embed power theories based on dependence (exchange theories) with power being based on the inverse of the expected value of alternative courses of action, and social network analysis focused on networks of powerful actors with significant power resources. The use of social networks depends on the formation of coalitions of powerful individuals and groups who then engage in political bargaining with other coalitions who want a different outcome. This synthetic theory is illustrated with two examples of economic development and political conflict in a moderately sized city
Between a rock and a hard place: corporate elites in the context of religion and secularism in Turkey
Drawing on discourse analyses of 36 in-depth interviews with elite business people from Turkey, the study identifies the networking patterns of new and established business elites in the context of economic liberalization and socioreligious transformation of the country. Through a comparative analysis of the so-called secular and religious elite networks, we demonstrate the role of institutional actors such as the government, and identity networks, based on religion and place of birth in shaping the form and content of social networks among business elites in Turkey. In order to achieve this, we operationalize Bourdieu's notion of theory of practice and Granovetter's theory of social networks, illustrating the utility of combining these approaches in explicating the form and content of social networks in their situated contexts, in which power and divergent interests are negotiated.Galatasaray University Research Fund [grant number 12.102.005]
How Can Social Networks Ever Become Complex? Modelling the Emergence of Complex Networks from Local Social Exchanges
Small-world and power-law network structures have been prominently proposed as models of large networks. However, the assumptions of these models usually lack sociological grounding. We present a computational model grounded in social exchange theory. Agents search attractive exchange partners in a diverse population. Agent use simple decision heuristics, based on imperfect, local information. Computer simulations show that the topological structure of the emergent social network depends heavily upon two sets of conditions, harshness of the exchange game and learning capacities of the agents. Further analysis show that a combination of these conditions affects whether star-like, small-world or power-law structures emerge.Complex Networks, Power-Law, Scale-Free, Small-World, Agent-Based Modeling, Social Exchange Theory, Structural Emergence
Communication Patterns in Mean Field Models for Wireless Sensor Networks
Wireless sensor networks are usually composed of a large number of nodes, and
with the increasing processing power and power consumption efficiency they are
expected to run more complex protocols in the future. These pose problems in
the field of verification and performance evaluation of wireless networks. In
this paper, we tailor the mean-field theory as a modeling technique to analyze
their behavior. We apply this method to the slotted ALOHA protocol, and
establish results on the long term trends of the protocol within a very large
network, specially regarding the stability of ALOHA-type protocols.Comment: 22 pages, in LNCS format, Submitted to QEST'1
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