Operators of online social networks are increasingly sharing potentially sensitive information about users and their relationships with advertisers, application developers, and data-mining researchers. Privacy is typically protected by anonymization, i.e., removing names, addresses, etc. We present a framework for analyzing privacy and anonymity in social networks and develop a new re-identification algorithm targeting anonymized socialnetwork graphs. To demonstrate its effectiveness on realworld networks, we show that a third of the users who can be verified to have accounts on both Twitter, a popular microblogging service, and Flickr, an online photo-sharing site, can be re-identified in the anonymous Twitter graph with only a 12 % error rate. Our de-anonymization algorithm is based purely on the network topology, does not require creation of a large number of dummy “sybil ” nodes, is robust to noise and all existing defenses, and works even when the overlap between the target network and the adversary’s auxiliary information is small. 1.

We investigate whether civil wars have economic causes. The model is based on utility theory, rebels will conduct a civil war if the perceived benefits outweigh the costs of rebellion. Using probit and tobit models the propositions are tested empirically. Four variables, initial income, ethnolinguistic fractionalisation, the amount of natural resources and initial population size are significant and strong determinants of the duration and the probability of civil wars. One important finding is that the relationship between civil wars and ethnic diversity is non-monotonic; highly fractionalised societies have no greater risk of experiencing a civil war than homogenous ones.

Introduction 1.1 Human sociality in comparative perspective E.O. Wilson (1975) described humans as one of the four pinnacles of social evolution. The other pinnacles are the colonial invertebrates, the social insects, and the non-human mammals. Wilson separated human sociality from that of the rest of the mammals because, with the exception of the social insect like Naked Mole Rats, only humans have generated societies of a grade of complexity that approaches that of the social insects and colonial invertebrates. In the last few millennia, human societies have even begun to exceed, in numbers of individuals and degree of complexity, the societies of ants, termites, and corals. Human social complexity is based on quite different principles than the ultra-sociality of any other species. In all other known cases, the constituent individuals of societies are either genetically identical, as in the colonial invertebrates, or closely related, as in the social insects and no

The asymmetry of activity in virtual communities is of great interest. While participation in the activities of virtual communities is crucial for a community's survival and development, many people prefer lurking, that is passive attention over active participation. Lurking can be measured and perhaps affected by both dispositional and situational variables. This work investigates the concept of cultural capital as situational antecedent of lurking and de-lurking (the decision to start posting after a certain amount of lurking time). Cultural capital is defined as the knowledge that enables an individual to interpret various cultural codes. The main hypothesis states that a user's cultural capital affects her level of activity in a community and her decision to de-lurk and cease to exist in very active communities because of information overload. This hypothesis is analyzed by mathematically defining a social communication network (SCN) of activities in authenticated discussion forums. We validate this model by examining the SCN using data collected in a sample of 636 online forums in Open University in Israel and 2 work based communities from IBM. The hypotheses verified here make it clear that fostering receptive participation may be as important and constructive as encouraging active contributions in online communities.

This article, derived from the 1996 American Association for Artificial Intelligence Presidential Address, explores the notion of intelligence from a variety of perspectives and finds that it "are" many things. It has, for example, been interpreted in a variety of ways even within our own field, ranging from the logical view (intelligence as part of mathematical logic) to the psychological view (intelligence as an empirical phenomenon of the natural world) to a variety of others. One goal of this article is to go back to basics, reviewing the things that we, individually and collectively, have taken as given, in part because we have taken multiple different and sometimes inconsistent things for granted. I believe it will prove useful to expose the tacit assumptions, models, and metaphors that we carry around as a way of understanding both what we're about and why we sometimes seem to be at odds with one another

In this paper, we discuss the advantages of investigating primate societies to build Multi-Agent Systems, and we present our preliminary results in this context. We first give an overview of primates' social competences, then we draw a parallel between the main problems found in the study of primate societies (regarding their social organization) and some of the most commonly encountered issues when designing Multi-Agent Systems. We describe a model of social cognition and perception that we have experimented. Its results show that some social concepts can be implemented by attaching importance to the interactions between the agents, instead of using a complicated individual-based model. Finally, we discuss the main extensions we are working on and propose applications to Multi-Agent technology. 1 Introduction Studying primates provides the biologists with good clues to human evolution, clues which do not only concern individual features such as bipedalism or cognitive abilities: it al...

... values in life --- is a central theme of the discussion. Finally, 3) the dependence of the analysis on an underlying pragmatic or action framework is highlighted: contemporary alternative frameworks for modeling development cannot satisfactorily address these issues of the social constitution of persons.

Abstract. Recently, we started to experience a shift from physical communities to virtual communities, which leads to missed social opportunities in our daily routine. For instance, we are not aware of neighbors with common interests or nearby events. Mobile social computing applications (MSCAs) promise to improve social connectivity in physical communities by leveraging information about people, social relationships, and places. This article presents MobiSoC, a middleware that enables MSCA development and provides a common platform for capturing, managing, and sharing the social state of physical communities. Additionally, it incorporates algorithms that discover previously unknown emergent geo-social patterns to augment this state. To demonstrate MobiSoC's feasibility, we implemented and tested on smart phones two MSCAs for location-based mobile social matching and place-based ad hoc social collaboration. Experimental results showed that MobiSoC can provide good response time for 1000 users. We also demonstrated that an adaptive localization scheme and carefully chosen cryptographic methods can significantly reduce the resource consumption associated with the location engine and security on smart phones. A user study of the mobile social matching application proved that geo-social patterns can double the quality of social matches and that people are willing to share their location with MobiSoC in order to benefit from MSCAs.

This article discusses narrative intelligence in the context of the evolution of primate (social) intelligence, and with respect to the particular cognitive limits that constrain the development of human social networks and societies.

Individuals value information that improves decision making. When social interactions complicate the decision process, acquiring information about others should be particularly valuable [1]. In primate societies, kinship, dominance, and reproductive status regulate social interactions [2, 3] and should therefore systematically influence the value of social information, but this has never been demonstrated. Here, we show that monkeys differentially value the opportunity to acquire visual information about particular classes of social images. Male rhesus macaques sacrificed fluid for the opportunity to view female perinea and the faces of highstatus monkeys but required fluid overpayment to view the faces of low-status monkeys. Social value was highly consistent across subjects, independent of particular images displayed, and only partially predictive of how long subjects chose to view each image. These data demonstrate that visual orienting decisions reflect the specific social content of visual information and provide the first experimental evidence that monkeys spontaneously discriminate images of others based on social status. Results and Discussion Most primates live in complex societies where the cultivation and exploitation of social relationships is associated with