| 1. |
- Holme, Petter, et al.
(författare)
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Structure and time evolution of an Internet dating community
- 2004
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Ingår i: Social Networks. - : Elsevier BV. - 0378-8733 .- 1879-2111. ; 26:2, s. 155-174
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Tidskriftsartikel (refereegranskat)abstract
- We present statistics for the structure and time evolution of a network constructed from user activity in an Internet community. The vastness and precise time resolution of an Internet community offers unique possibilities to monitor social network formation and dynamics. Time evolution of well-known quantities, such as clustering, mixing (degree-degree correlations), average geodesic length, degree, and reciprocity is studied. In contrast to earlier analyses of scientific collaboration networks, mixing by degree between vertices is found to be disassortative. Furthermore, both the evolutionary trajectories of the average geodesic length and of the clustering coefficients are found to have minima.
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| 2. |
- Grönlund, Andreas, et al.
(författare)
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Networking the seceder model : Group formation in social and economic systems
- 2004
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Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - 1063-651X .- 1095-3787. ; 70:3, s. 036108-
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Tidskriftsartikel (refereegranskat)abstract
- The seceder model illustrates how the desire to be different from the average can lead to formation of groups in a population. We turn the original, agent based, seceder model into a model of network evolution. We find that the structural characteristics of our model closely match empirical social networks. Statistics for the dynamics of group formation are also given. Extensions of the model to networks of companies are also discussed.
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| 3. |
- Holme, Petter
(författare)
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Efficient local strategies for vaccination and network attack
- 2004
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Ingår i: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 68:6, s. 908-914
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Tidskriftsartikel (refereegranskat)abstract
- We study how a fraction of a population should be vaccinated to most efficiently stop epidemics. Our starting point is that only local information-about the neighborhood of specific vertices-is usable in practice. For this reason we consider only local vaccination strategies. The efficiency of the vaccination strategies is investigated with both static and dynamic measures. We test the strategies on real-world networks and model networks with real-world characteristics. Among other things, we find that the most efficient strategy for many real-world situations is to iteratively vaccinate the neighbor of the previous vaccinee that has the most links out of the neighborhood.
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| 4. |
- Holme, Petter, et al.
(författare)
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Subnetwork hierarchies of biochemical pathways
- 2003
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Ingår i: Bioinformatics. - : Oxford University Press (OUP). - 1367-4803 .- 1367-4811. ; 19:4, s. 532-538
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Tidskriftsartikel (refereegranskat)abstract
- Motivation: The vastness and complexity of the biochemical networks that have been mapped out by modern genomics calls for decomposition into subnetworks. Such networks can have inherent non-local features that require the global structure to be taken into account in the decomposition procedure. Furthermore, basic questions such as to what extent the network (graph theoretically) can be said to be built by distinct subnetworks are little studied. Results: We present a method to decompose biochemical networks into subnetworks based on the global geometry of the network. This method enables us to analyze the full hierarchical organization of biochemical networks and is applied to 43 organisms from the WIT database. Two types of biochemical networks are considered: metabolic networks and whole-cellular networks (also including for example information processes). Conceptual and quantitative ways of describing the hierarchical ordering are discussed. The general picture of the metabolic networks arising from our study is that of a few core-clusters centred around the most highly connected substances enclosed by other substances in outer shells, and a few other well-defined subnetworks.
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| 6. |
- Medvedyeva, Kateryna, et al.
(författare)
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Dynamic critical behavior of the XY model in small-world networks
- 2003
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Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - : American Physical Society. - 1063-651X .- 1095-3787. ; 67:3, s. 036118-
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Tidskriftsartikel (refereegranskat)abstract
- The critical behavior of the XY model on small-world network is investigated by means of dynamic Monte Carlo simulations. We use the short-time relaxation scheme, i.e., the critical behavior is studied from the nonequilibrium relaxation to equilibrium. Static and dynamic critical exponents are extracted through the use of the dynamic finite-size scaling analysis. It is concluded that the dynamic universality class at the transition is of the mean-field nature. We also confirm numerically that the value of dynamic critical exponent is independent of the rewiring probability P for Pgreater than or similar to0.03.
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