Research Of Trust Model Based On The Node Service Attribute In Grid Environment

The grid technology is thought to be the next wave of improvement of information technology, which is also considered to be the next generation internet.The grid has the following characters: resources in the grid are geographically distributed, resources and clients are connected through wide-area network such as internet; the categories and quantities of resources are tremendous, and resources need to cooperate with each other to some extent; resources are dynamic including the attributes changes, the migration and replication in the grid; resources work in heterogeneous platforms administrated by different policies.Grid system consists of various resources ,and the resources have more features of dynamic change and heterogeneous systems, so the trust problems in grid environment are being paid more and more attention to and a hot topic in currently grid research. It refers to the trust management between consumer and service provider. Therefore,in order to solve the trust issues incurred by the dynamic and uncertainty of grid environment, trust model is introduced into grid to evaluate the network behavior of node ,and the evaluation of node's network behavior is used to reflect it's reliability.However,many of the trust systems consider only one criterion to evaluate trust; it's simple but not so effective and has restricted applications. In order to resolve the trust problems due to the multi-criteria of node in grid environment.On the basis of current trust models,a trust model in grid based on the service attributes of node was proposed in this paper to solve this issue.In this model, the hierarchical tactic was proposed to treat the nodes beforehand.Every node can acquire the quantitative value,which shows us the node's credibility and is mainly used to choose the voter during the decision process. In this paper,two schemes are adopted to implement the hierarchical tactic.The first scheme is applicated when there are no centralized nodes in grid environment ,and the iteration methos is adopted in this shceme. The second scheme is applicated when there are centralized nodes in grid environment ,and a matrix which coms from the service diagram is adopted to perform comprehensive calculations in this shceme.In the trust decision processes,triangular fuzzy number was adopted to represent trust relationship,attribute table and weight vectors were defined,which were used to discover the differences of attribute preference information among nodes, at last ,the triangular fuzzy number and TOPSIS method was combined to caculate the relative approach degree of service node candidate and it make the trust decision more reasonably and more accurate. The attribute table and weight vectors can be modified to serve different needs.It shows that this model has excellent expandability.The results of experiments and analysis shows that,this model has the ability to make rational decisions when every node has different attribute preference information and is able to evaluate the trust relations between nodes in grid more precisely.