一种基于ATN的网格服务选择模型

Grid Services Selection Model Based on Automated Trust Negotiation

网格服务组合可以将现有的单个服务组合成复杂的服务或者应用,而网格服务组合的关键在于对单个服务的选择.提出一种基于ATN的网格服务组合二级信任ATN-CTT模型和算法.该模型上层对应于服务组合信任模板(SCTT),下层对应于SCTT中每个节点的可选择服务.每类待选的服务依据其信任度值组成信任矩阵,按照信任矩阵中信任度值产生服务组合信任模板,依据ATN的访问控制策略来使用信任模板中对应的服务.实验证明了这种模型的有效性和服务组合路径的稳定性和可靠性.将已有的信任机制和ATN结合起来,能够解决在网格动态环境下陌生主体间的安全访问控制问题和服务选择问题.

One of the most promising advantages of grid service technology is the possibility of creating added-value services by combining existing ones. A key step for composing and executing services lies in the selection of the individual services. A layered grid service selection model, ATN_CTT（automated trust negotiation- composition trust template）, and algorithm based on ATN （automated trust negotiation） is presented. The top layer is corresponding to service composition trust template （SCTT）, and the bottom layer is the selective services of each node in the SCTT. Each service can be visited by it＇s least disclosure tree（LDT）under the ATN access control strategy. The candidate services form a trust matrix in accordance with their trust value and the SCTT is structured from the each row max of the matrix. At the process of the service composition, the SCTT can ensure the selected service with max trust value. With the ATN access control strategy the services can be accessed and used. Experiments show the validity of the model and it can keep the service composition path more stabilization and stabilization. Combining trust mechanism with ATN can solve access control problems to stranger subjects and service selection in grid dynamic environment.