Peer-to-Peer (P2P) networks are highly dynamic systems which are very popular for content distribution in the Internet. A single peer remains in the system for an unpredictable amount of time, and the rate in which peers enter and leave the system, i.e. the churn, is often high. A user that is obtaining content from a selected peer is frequently informed that particular peer is not available an...

We consider several distributed collaborative key agreement protocols for dynamic peer groups. This problem has several important characteristics which make it different from traditional secure group communication. They are (1) distributed nature in which there is no centralized key server, (2) collaborative nature in which the group key is contributory; i.e., each group member will collaborati...

Security in peer groups is challenging due to lack of a centralized authority, and due to varied security requirements of its applications. Significant work has been done to solve the security issues of peer groups such as key management and anonymity. However, admission control, an important prerequisite for peer group security is not addressed yet (or assumed), which is extremely challenging ...

Sociologists have seen a dramatic increase in the size and availability of social network data. This represents a poverty of riches, however, since many of our analysis techniques cannot handle the resulting large (tens to hundreds of thousands of nodes) networks. In this paper, I provide a method for identifying dense regions within large networks based on a peer influence model. Using softwar...

This study investigated the consistency of interpersonal perceptions regarding people who exhibit features of personality disorders. The participants (N=82) were college students who were assessed for features of personality disorders, using both self-report and peer nominations at Time 1. Two years later, participants attended four meetings in groups of 7 to 12 people for a total of 2 hours. G...

Community-based peer social networks of young boys with developmental delays and parental arranging and monitoring of their child's peer contacts were examined. Comparisons were made to matched groups of children who were developing typically and to children with communication disorders. Results showed more limited peer social networks for both groups of children with disabilities based primari...

In recent years, group-oriented applications and collaborative protocols are gaining popularity. This calls for group key management which forms the basic building block in achieving secure group communication. The points that differentiate it from the traditional communication are that they do not have a centralized server but a distributed system, group key being contributory and dynamic natu...

INTRODUCTION Peer tutor-led small group sessions are a valuable learning strategy but students may lack confidence in the absence of a content expert. This study examined whether faculty reinforcement of peer tutor-led small group content was beneficial. METHODS Two peer tutor-led small group sessions were compared with one faculty-led small group session using questionnaires sent to student ...