Data Depedency Based Trust Evaluation for BPEL Processes

Composite services implement value-added functionality by composing service components with smaller granularity. Trust is an important criterion to judge whether a composite service can behave as expected. A feasible trust evaluation method for composite services is needed, which can guide service selection for users and the trust-based optimization and evolution for composite services. In this paper, a data dependency based trust evaluation approach for composite services in Business Process Execution Language (BPEL) is proposed. Firstly, we derive define-use pairs of variables to describe data dependency between service components in BPEL processes modeled by extensible BPEL Flow Graph (XBFG), in addition, dependency links including both direct and indirect data dependencies are used to evaluate the trust values of these service components, furthermore, on the basis of BPEL structure and XBFG, reduction rules are proposed to evaluate the global trust values of BPEL processes. Experiment results demonstrate that the proposed approach is effective for the trust evaluation of BPEL composite services and stable enough with the growing number of service components in BPEL.