The Study Of Dynamic Trust Relationship Modeling And Managing

With the rapid development of the Internet and computer technology, trust model and trust management become essential parts of e-commerce, distributed systems and network security. The study of dynamic trust relationship modeling and managing focuses on the complexity and the dynamicity of trust relationship in the Internet, and tries to develop new trust models and trust management techniques for newly appeared applications. Compared with traditional trust models, dynamic trust models treat trust relationship as changing variables influenced by time, trust context and the properties in trust, in which the dynamic procedures for collecting evidence, evaluating trust, managing trust and making trust-based decision are maintained. As one of the hot areas in trust management research nowadays, dynamic trust model is vital in solving trust problems in the Internet environment.By analyzing the requirements of trust management in Internet applications and some limitations of existing work, this dissertation focuses on the problems of analyzing the dynamic of trust, modeling dynamic trust relationship and making trust-based decision. The trust management in P2P environment and the decision making based on risk and trust are also studied.The major contribution of this thesis includes:1. As a basic dynamic trust model, the Time-Related Trust Model (TRTM) is proposed based on the extension of subjective logic.In TRTM, time is introduced as a metric to measure the dynamic of trust. Time-related opinion is defined to represent trust relationship, in which the dynamic of trust is expressed as time-related functions. The traditional operators and the non-traditional evidential operators are also defined. Compared to subjective logic, the abilities to model and adapt to the dynamicity of trust relationship are improved in TRTM. The simulations illustrate that TRTM gains benefit in adaptability and transaction distribution which leads to a higher rate of successful transactions when modeling dynamic trust.2. DWTrust: a Distributed Trust Model Based on Dynamic Weights is proposed. DWTrust is a dynamic trust model for P2P applications based on time-related trust modelwhich is featured with a new trust computation method and a local community management strategy. DWTrust adopts a novel feedback control mechanism to implement the computation of trust in which a set of subjective weights are set and adjusted in time to reflect the dynamic of the trust environment. The trust evaluation in DWTrust avoids the complex computation in trust assessment and has better adaptability to the dynamic of trust. Meanwhile, algorithms for community trust update and community management are designed. The novel local trust based...