This study examines the social networks of prisoners in the period from before to after their incarceration. We use unique panel data on 702 prisoners and their core discussion networks. Our results show that while the size of prisoners’ core discussion network is stable, prisoners have replaced 60% of their core discussion network members after incarceration. Moreover, multinomial multilevel m...

This paper proposes a new formal model and semantics for answering queries in a multilevel polyinstantiated database. A polyinstantiated database may contain some contradict,ory facts distinguished by their classification. The main objective of this paper is then to provide the user cleared at a given level with a consistent and complete view of the multilevel database corresponding to his clea...

This paper describes the development of a multilevel model for investigating the impact of organizational social web site (SWS) usage on individual and team performance. Despite the SWS focus on collective phenomena – such as crowd sourcing and collective intelligence – previous research on SWS usage in general does not investigate it as a multilevel phenomenon. Our paper addresses this gap by ...

For applications with high requirements on the confidentiality of data a level-based access control policy may be appropriate. Designing such security critical applications is a less understood issue and thus complicated task. To guide a security administrator or database designer and in order to simplify the design activity several guidelines and a powerful modeling technique are necessary. Th...

Multilevel modeling is a technique that has numerous potential applications for social and personality psychology. To help realize this potential, this article provides an introduction to multilevel modeling with an emphasis on some of its applications in social and personality psychology. This introduction includes a description of multilevel modeling, a rationale for this technique, and a dis...

Positive emotions are implicated in affiliation and cooperation processes that are central to human social life. For this reason, we hypothesized that people should be highly aware of and responsive to the positive emotions of others. Study 1 examined awareness by testing the accuracy with which perceivers tracked others’ positive emotions. Study 2 examined responsiveness by testing whether pos...

Multilevel transactions have been proposed for multilevel secure databases; in contrast to most proposals, such transactions allow users to read and write across multiple security levels. The security requirement that no high level operation in uence a low level operation often con icts with the atomicity requirement of the standard transaction processing model. In particular, others have shown...

of the database. The goal of the prototype is to achieve a concise and non-conflicting specification of the security constraints. Based on a concrete example of the application domain, the database designer and the security officer (or trusted users) are able to examine by using the prototype the adequacy of the database design and of the security classifications specified. In this paper we giv...