Papers by Keyword: Groups

Abstract: In this paper, a predator-prey system with functional response is studied,and a set of sufficient conditions are obtained for the stability of equilibrium point of the system. Moreover, optimal harvesting policy is obtained by using the maximal principle,and numerical simulation is applied to illustrate the correctness.

Abstract: In this paper, we propose a temporal-based aythorization model for Group-centric Secure Information Sharing(g-SIS) . The traditional approach to information sharing focuses on attaching attributes and policies to an object as it is disseminated from producer to consumers in a system. In contrast, group-centric sharing brings subjects and objects together in a group to facilitate sharing. In such contexts, authorizations are influenced by the temporal ordering of subject and object group membership. That is, the authorizations are decided by the time that subject joins group and the time that object is added to group. But, the model doesn’t consider the time constraint of group enabling and access enabling. For example, a secure meeting room is open only at 8:00—10:00 am and 15:00—17:00 pm every Monday. We develop a temporal-based authorization model for group-centric information sharing which takes the temporal intervals of group and access enabling into consideration. We also discuss a usage scenario to illustrate practical application in secure meeting system.

Abstract: A robust trust model based on group for P2P environments-RobustGroup is put forward, which measures trust values based on the group relationship between requesting peers and serving peers. Trust’s aging time and peers’ similarity are introduced with weights for direct trust and indirect trust being dynamically adjusted in trust calculation against critical issues affecting trust evaluation such as false feedback, incentive and penalty, Whitewashing behavior, dynamic trust. Simultaneously service control policies are implemented on the basis of groups, and peers’ initial trust is determined by behavior in “silent time”. The simulation shows that the proposed model has advantages in successful requests and system overhead over the existing P2P trust models.