***** To join INSNA, visit http://www.insna.org *****
Barry Wellman
_______________________________________________________________________
S.D. Clark Professor of Sociology, FRSC NetLab Director
Department of Sociology 725 Spadina Avenue, Room 388
University of Toronto Toronto Canada M5S 2J4 twitter:barrywellman
http://www.chass.utoronto.ca/~wellman fax:+1-416-978-3963
Updating history: http://chass.utoronto.ca/oldnew/cybertimes.php
_______________________________________________________________________
Robustness and modular structure in networks , arXiv
Abstract: Many complex systems, from power grids and the internet, to the
brain and society, can be modeled using modular networks. Modules, densely
interconnected groups of elements, often overlap due to elements that
belong to multiple modules. The elements and modules of these networks
perform individual and collective tasks such as generating and consuming
electrical load, transmitting data, or executing parallelized
computations. We study the robustness of these systems to the failure of
random elements. We show that it is possible for the modules themselves to
become isolated or uncoupled (non-overlapping) well before the network
falls apart. When modular organization is critical to overall
functionality, networks may be far more vulnerable than expected. *
[12] Robustness and modular structure in networks, James P. Bagrow, Sune
Lehmann, Yong-Yeol Ahn, 2011/02/24, arXiv:1102.5085 [12]
http://arXiv.org/abs/1102.5085
_________________________________________________________________
10. Explosive Synchronization Transitions in Scale-free Networks , arXiv
Excerpt: The emergence of explosive collective phenomena has recently
attracted much attention due to the discovery of an explosive percolation
transition in complex networks. In this Letter, we demonstrate how an
explosive transition shows up in the synchronization of complex
heterogeneous networks by incorporating a microscopic correlation between
the structural and the dynamical properties of the system.
* [14] Explosive Synchronization Transitions in Scale-free Networks, Jesus
Gomez-Gardenes, Sergio Gomez, Alex Arenas and Yamir Moreno, 2011/02/23,
arXiv:1102.4823
[14] http://arXiv.org/abs/1102.4823
_________________________________________________________________
12. General coevolution of topology and dynamics in networks , arXiv
Abstract: We present a general framework for the study of coevolution in
dynamical systems. This phenomenon consists of the coexistence of two
dynamical processes on networks of interacting elements: node state change
and rewiring of links between nodes. The process of rewiring is described
in terms of two basic actions: disconnection and reconnection between
nodes, both based on a mechanism of comparison of their states. Different
rewiring rules can be expressed in this scheme. We assume that each
process, rewiring and node state change, occurs with its own probability,
independently from the other. The collective behavior of a coevolutionary
system is characterized in the space of parameters given by these two
probabilities. As an application, for a voterlike node dynamics we find
that reconnections between nodes with similar states lead to network
fragmentation. The critical boundaries for the onset of fragmentation in
networks with different properties are calculated on this space. We show
that coevolution models correspond to curves on this space, describing
coupling relations between the probabilities for the two processes. The
occurrence of network fragmentation transitions are predicted for diverse
models, and agreement is found with some earlier results.
* [16] General coevolution of topology and dynamics in networks, J.L.
Herrera, M.G. Cosenza, K. Tucci, J.C. González-Avella, 2011/02/17,
arXiv:1102.3467
[16] http://arXiv.org/abs/1102.3467
_________________________________________________________________
15. Prosperity is associated with instability in dynamical networks ,
arXiv
Abstract: Social, biological and economic networks evolve with recurrent
fragmentation and re-formation, often explained in terms of external
perturbations. We show that these phenomena can be a direct consequence of
imitation and endogenous conflicts between 'cooperators' and 'defectors'.
We employ a game-theoretic model of dynamic network formation, where
prosperous individuals are more likely to be selected as role-models by
newcomers who imitate their strategies and their connections. We find that
cooperators promote well connected highly prosperous networks and
defectors cause the network to fragment and lose its prosperity; defectors
are unable to maintain the highly connected networks they invade. Once the
network is fragmented, it can be reconstructed by a new invasion of
cooperators. We observe that prosperity is associated with instability:
cooperation is most productive when it is unstable.
* [20] Prosperity is associated with instability in dynamical networks,
Matteo Cavaliere, Sean Sedwards, Corina E. Tarnita, Martin A. Nowak,
Attila Csikász-Nagy, 2011/02/24, arXiv:1102.4947 [20]
http://arXiv.org/abs/1102.4947
_________________________________________________________________
15.01. Two wrongs do not make a right: The initial viability of different
assessment rules in the evolution of indirect reciprocity , Journal of
Theoretical Biology
Excerpt: Indirect reciprocity models are meant to correspond to primitive
moral systems, in which individuals assess the interactions of third
parties in order to condition their cooperative behavior [...] Here, I
present a general analytical model of indirect reciprocity and show that
the class of assessment rules which positively judges a refusal to help
scofflaws cannot invade a population of defectors, whereas the other class
can.
* [21] Two wrongs do not make a right: The initial viability of different
assessment rules in the evolution of indirect reciprocity, Panchanathan K,
February 2011, DOI: 10.1016/j.jtbi.2011.02.009, Journal of Theoretical
Biology, in Press * Contributed by [22] Segismundo
[21] http://dx.doi.org/10.1016/j.jtbi.2011.02.009
_________________________________________________________________
_____________________________________________________________________
SOCNET is a service of INSNA, the professional association for social
network researchers (http://www.insna.org). To unsubscribe, send
an email message to [log in to unmask] containing the line
UNSUBSCRIBE SOCNET in the body of the message.
|