Abstract: This paper proposes a data dependency based trust evaluation approach for business process execution language for Web services (BPEL). Firstly, it derives both direct and indirect data dependencies between service components in BPEL processes modeled by extensible BPEL flow graph (XBFG) and constructs dependency links to evaluate the trust values of these service components. Furthermore, on the basis of BPEL structures and XBFG, it proposes reduction rules to evaluate the global trust values of BPEL processes. Experimental 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.

Key words: data dependency, dependency link, trust evaluation, reduction rules, extensible BPEL flow graph (XBFG)

摘要： 提出了一种基于数据依赖的Web服务编程语言（business process execution language for Web services，BPEL4WS，简称BPEL）的可信性评估方法。利用扩展BPEL控制流图（extensible BPEL flow graph，XBFG）对BPEL进行建模，通过建模获得组件间的直接和间接数据依赖关系，并构造依赖链用以计算组件的信任值。根据BPEL组合服务的控制结构，在XBFG上通过约减规则对BPEL组合服务可信性进行评估。实验结果表明，基于数据依赖的组合服务可信性评估方法可以有效地评估BPEL组合服务的可信性，并且这种评估方法较为稳定，不会随着组件数量的增加而影响评估结果。

关键词: 数据依赖, 依赖链, 可信评估, 约减规则, 可扩展的BPEL控制流图（XBFG）