Abstract: The largcscale, heterogeneous, dynamic, distributed and autonomous network results in uncertainty and deceptive of resources and services, so an effective trust mechanism should be built to ensure transaction safety. But current trust evaluation approaches solely based on fuzzy logic and feedback arc inaccurate and ineffective. This paper presented a method which is based on set pair analysis theory to overcome the shortcoming that a fuzzy concept must be denoted by a precise,only strict membership function in fuzzy math. This model considers not only the feedback information, but also the service capacity that resources can achieve. hhe authors proposed two algorithms of service selection based on the trust model. Simulations prove that the algorithms can efficiently increase the success rate of task execulion.

Key words: Scrvice, Trust modcl,Set pair analysis,Connection numbers,Scrvice selection