Social Cohesion and Cooperation for Public Goods

A cohesive network keeps groups together and enables members to communicate about and cooperate for public goods. For ongoing cooperation, group members have to know if their group members cooperate or defect, but this information—mostly through gossip—is threatened by noise and biases. If there are redundant information channels, however, errors in monitoring and transmission in one imperfect channel can, to some degree, be corrected by information through another imperfect channel, and may lead to higher levels of cooperation. An influential conceptualization of social cohesion based on redundancy is K-connectivity: the minimum number (K) of node-independent paths connecting pairs of nodes in a group’s network. Ina lab experiment, we tested if higher K-connectivity yields higher levels of cooperation for public goods, controlling for a number of other network effects such as density, size, and average distance. We do not find the hypothesized effect, which might be due to a not-earlier-found shortcoming of the concept, and we propose a solution

Концептуальные положения моделирования финансовых потоков коммерческих банков

Развитие рыночного хозяйствования происходит в условиях множества противоречий, которые являются специфическими для современного состояния отечественной экономики. Это проистекает в значительной мере из-за сбоев экономической политики в стране. Не определены пока еще до конца меры и формы государственного вмешательства в экономику.Розвиток ринкового господарювання відбувається в умовах безлічі суперечностей, які є специфічними для сучасного стану вітчизняної економіки. Це виникає значною мірою через збої економічної політики в країні. Не визначені поки що до кінця міри і форми державного втручання в економіку

La responsabilité de protéger

4e de couverture : La responsabilité de protéger est un concept issu des travaux de la Commission internationale de l’intervention et de la souveraineté des États (CIISE). Établie en 2000 à l’initiative du Canada, elle a recherché à dépasser les controverses inhérentes aux débats relatifs au « droit d’intervention humanitaire ». Aux fins d’atteindre cet objectif, la Commission a forgé un nouveau concept, la « responsabilité de protéger », qui permît de concilier, plutôt qu’opposer, les notions de souveraineté et d’intervention. Depuis lors, la responsabilité de protéger a fait l’objet de vives controverses en droit international. Intégrée dans une résolution de l’Assemblée générale de l’ONU en septembre 2005, appliquée par le Conseil de sécurité lors de la crise en LIBYE de mars 2011, le concept se trouve, aujourd’hui, au centre des débats se rapportant au cadre juridique de la protection des populations civiles. La présente thèse entend examiner les différentes implications juridiques de la responsabilité de protéger, en optant pour une démarche résolument positiviste. La réflexion proposée tente d’en embrasser les différents aspects, tant conceptuels qu’opérationnels, aux fins d’aboutir à une étude globale, synthétique et actualisée du concept. Partant, une interrogation commandera l’ensemble de notre réflexion : l’émergence de la responsabilité de protéger a-t-elle, en droit international, permis une amélioration de la protection des populations civiles

Emergence of scale-free close-knit friendship structure in online social networks

Despite the structural properties of online social networks have attracted much attention, the properties of the close-knit friendship structures remain an important question. Here, we mainly focus on how these mesoscale structures are affected by the local and global structural properties. Analyzing the data of four large-scale online social networks reveals several common structural properties. It is found that not only the local structures given by the indegree, outdegree, and reciprocal degree distributions follow a similar scaling behavior, the mesoscale structures represented by the distributions of close-knit friendship structures also exhibit a similar scaling law. The degree correlation is very weak over a wide range of the degrees. We propose a simple directed network model that captures the observed properties. The model incorporates two mechanisms: reciprocation and preferential attachment. Through rate equation analysis of our model, the local-scale and mesoscale structural properties are derived. In the local-scale, the same scaling behavior of indegree and outdegree distributions stems from indegree and outdegree of nodes both growing as the same function of the introduction time, and the reciprocal degree distribution also shows the same power-law due to the linear relationship between the reciprocal degree and in/outdegree of nodes. In the mesoscale, the distributions of four closed triples representing close-knit friendship structures are found to exhibit identical power-laws, a behavior attributed to the negligible degree correlations. Intriguingly, all the power-law exponents of the distributions in the local-scale and mesoscale depend only on one global parameter -- the mean in/outdegree, while both the mean in/outdegree and the reciprocity together determine the ratio of the reciprocal degree of a node to its in/outdegree.Comment: 48 pages, 34 figure

Linking spatial pattern of bottom fish assemblages with water masses in the North Sea

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75155/1/j.1365-2419.2008.00495.x.pd

Composition and Structure of a Large Online Social Network in the Netherlands

Limitations in data collection have long been an obstacle in research on friendship networks. Most earlier studies use either a sample of ego-networks, or complete network data on a relatively small group (e.g., a single organization). The rise of online social networking services such as Friendster and Facebook, however, provides researchers with opportunities to study friendship networks on a much larger scale. This study uses complete network data from Hyves, a popular online social networking service in the Netherlands, comprising over eight million members and over 400 million online friendship relations. In the first study of its kind for the Netherlands, I examine the structure of this network in terms of the degree distribution, characteristic path length, clustering, and degree assortativity. Results indicate that this network shares features of other large complex networks, but also deviates in other respects. In addition, a comparison with other online social networks shows that these networks show remarkable similarities