Dionysios Konstantinos Kostoulas , 2005
نویسندگان
چکیده
Distributed systems such as the Internet, the Grid, peer-to-peer systems, etc., have grown to be very large. As the number of entities grows, these systems tend to become unreliable. The establishment of trust becomes difficult in large distributed applications since entities have only partial knowledge about the group and are not expected to interact with only known entities. This introduces uncertainty and risk because some entities may attempt to behave improperly and misuse or abuse the system by sharing malicious content. As groups grow large in distributed applications, making repeated interactions between known entities infrequent, individual entities cannot rely solely on their own past experience to recognize those that behave badly. Moreover, the complexity of large distributed systems makes the enforcement of proper behavior by a centralized authority unwieldy. Under these circumstances, reputation mechanisms need to be used to assess the reliability of entities and of resources shared by them. In this thesis, we first propose a passive (zero cost) algorithm for estimating the size of a large and dynamic distributed group. We then present a new distributed trust rating scheme that works on two trust levels: direct trust and rater trust. Finally, we present a range of reputation-based trust spreading algorithms; one of them utilizes the previously developed estimation algorithm. Mathematical analysis and simulation results are presented where needed.
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تاریخ انتشار 2005