Computer Engineering and Applications ›› 2011, Vol. 47 ›› Issue (22): 227-232.
• 工程与应用 • Previous Articles Next Articles
LIU Yi1,XUE Hongchao2,XIA Yunni2,YANG Jun1
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刘 毅1,薛红超2,夏云霓2,杨 骏1
Abstract: Web service composition refers to the creation of new services by combining functionalities provided by existing ones.Current Web service choreography proposals,such as WSCI,WS-CDL and BPEL,provide notations for describing the message flows in Web service collaborations.The kernel of WSCI consists of simple communication primitives that may be combined using control-flow constructs expressing sequence,branching,parallelism,synchronization,etc.Many efforts have been made on functional formalization and property verification of WSCI-based service compositions.However,performance facet of WSCI-based service composition is yet to be given,the importance it deserves.In this paper,a stochastic-Petri-net-based approach is introduced to predict the performance of Web service choreographed using WSCI.This approach translates WSCI-based composition into general stochastic Petri net and obtains analytical estimation of process-completion-time based on the continuous-time Markov chain derived from the Petri net.In the case study,the Monte-carlo experiments and confidence interval analysis are used to validate theoretical evaluations.
Key words: choreography-based service composition, stochastic-petri-net, performance evaluation, confidence interval analysis
摘要: 伴随Web服务而生的服务组装技术,因能实现服务的复用和增值而成为学术界和工业界关注的焦点。目前主流的服务组合规范可以分为基于编写(orchestration-based规范,如WS-BPEL)和基于排编(choreography-based规范,如WSCI和WS-CDL)两大类。目前对服务组合规范的研究多偏重于功能分析和性质验证的方面,而数量化特性,特别是性能的研究却相对薄弱。运用随机Petri网对基于WSCI规范描述的服务组合进行了建模和性能分析。基于WSCI的组合服务转换为随机Petri网描述,在其基础上导出连续时间马氏过程的状态变迁模型,在马氏过程的转移强度矩阵上进行一系列计算以获得对性能的评价。在实例研究中运用蒙特卡洛实验和置信区间分析的方法,对上一步获得的理论结果进行了检验。
关键词: 服务组合, 随机petri网, 性能评估, 置信区间分析
LIU Yi1,XUE Hongchao2,XIA Yunni2,YANG Jun1. Stochastic-petri-net-based approach to modeling and performance evaluation of choreography-based service composition[J]. Computer Engineering and Applications, 2011, 47(22): 227-232.
刘 毅1,薛红超2,夏云霓2,杨 骏1. 服务组合排编规范性能分析研究[J]. 计算机工程与应用, 2011, 47(22): 227-232.
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http://cea.ceaj.org/EN/Y2011/V47/I22/227