Research On Internetware-Oriented Trust Model

With the popularization and development of Internet, the runtime environmentof software begin shift from static and closed, controlled to dynamic, open andhard-controlled. It is a challenge of computer software technology sharing andintegrating all kinds of resources.In order to cope with the challenge, the concept of Internetware is proposed.Trust is an important thing for security and reliability of software systems. Afterfeatures of Internetware and trust are analyzed, we do some researches onInternetware-oriented trust model.The main work of this thesis as follows:Direct trust is the fundamental of many other trust relationships in opensystems, and also the focal problem of trust manage. Consider entities’ behaviors asbinary events, the result sequence is divided into several windows thus they followthe binomial distribution. Suppose that the parameter is a random variable followsBeta distribution, then the Beta-Binomial (BB) distribution model is obtained. Theparameters of Beta distribution is estimated by EM algorithm, therefore, the directtrust value is got. The model overcomes shortcomings of single distribution, anddepicts the dynamic of trust well. Simulation experiments show that the modelgives a more accurate estimation of direct trust and more reasonable and scientific.On the basis of continuous process, recommendation trust model is built fordepicting indirect trust, the most complicated trust relationship. The model is alsosignificant for security and reliability of open environment and systems. Afterfactors influencing indirect trust are quantified, the filtrated recommendations areregarded as samples from normal process and Bayesian estimation value ofposteriori distribution expectation is obtained from calculation. Then, after anelaborate discussion of the trust evolution and relationship between trust value andtrustworthiness, some propositions and proofs are proposed. Experimental datashow that with the capacity of resisting malicious attacks improved, the modelgives a more effective and precise result, which is also consistent withmathematical deduction.In Internetware environment, overall trust degree by combing direct andindirect trust is the basis of coordination between software entities. By quantifying factors influencing weights, the least-square method is used for predetermination ofit value based on history data. Then a set of rules are provided for preventing directexperiments reused, therefore, rumors are avoided.