基于流演算的Web服务自动组合方法

An Approach for Automatic Web Services Composition Based on Fluent Calculus

近年来,基于语义的Web服务组合,尤其是Web服务的自动组合方法已成为服务计算领域的一个研究热点.实现了从一个OWL-S过程模型到流演算概念的映射,并给出了相应的转换算法.在此基础上,提出了一个新颖的、基于流演算形式化体系的Web服务自动组合方法.该方法采用前推推理机制对状态和动作进行推理,有效地克服了以传统的情景演算为代表的人工智能规划算法执行效率较低的问题.设计实现了一个实验性的原型系统,结合一个旅游行程规划的实例说明了本文提出的方法的有效性.对提出的BCABFC(Backward-Chaining Algorithm Based On Fluent Calculus)算法与基于情景演算的同类算法进行性能比较,实验结果表明该算法具有较好的性能.

In recent years,semantics-based Web Services composition,especially automated composition method has become popularity in the research area of Service Computing.This paper has identified a mapping between an OWL-S process ontology and the fluent calculus concepts.We present an algorithm to translate OWL-S service descriptions into an equivalent fluent calculus service specification.This paper presents a novel approach for automatic Web service composition method based on the formalism of fluent calculus.In our approach,the Web service composition process is viewed as an AI planning problem in the fluent calculus formalism.We show how the planning capabilities of the fluent calculus can be used to automatically generate an Abstract composition model in terms of user personalized requests.This method applies the principle of progression for reasoning the status and action of the object.As a result,it brings a higher efficiency than traditional AI planning algorithms characterized by Situation Calculus.For testing our composition method,we have designed and implemented an experimental prototype and demonstrate its effectiveness with the help of an application scenario from the travel planning domain.Comparing with similar algorithm based on situation calculus,experimental results show that the BCABFC algorithm（Backward-Chaining Algorithm Based On Fluent Calculus） yields better performance over other algorithms.