关键词: 层次化服务流程（LSP）, 结构化服务流程, 业务过程执行语言（BPEL）, 模型转换, 执行效率

Abstract: Artificial intelligence (AI) planning based service composition algorithms generate layered service process (LSP) which is executed and driven by data flow between service activities instead of the control flow in traditional block-structured service processes. To enable LSP to be executed directly on business process execution language (BPEL) engines, this paper researches on a method of transforming LSP into BPEL and pursues the optimization of execution efficiency of the obtained BPEL. Firstly this paper presents the formal model of LSP, and analyzes three typical transformation strategies from LSP to BPEL, i.e., partition by nodes, partition by layers, and partition by blocks, including the performance comparison among them. Aiming at the “partition by layers” strategy, this paper proposes nine rules to guide the partition of LSP into blocks with the maximum concurrency degree during the BPEL execution, and presents a block-partition algorithm and a block-merge algorithm to generate the corresponding BPEL. Through an LSP case, this paper demonstrates the transformation process, and the experimental results validate that the proposed method can obtain better performance than other transformation strategies.

Key words: layered service process (LSP), structured service process, business process execution language (BPEL), model transformation, execution efficiency