【作者】 鲍爱华；

【导师】 张维明； 姚莉；

【作者基本信息】 国防科学技术大学 ， 管理科学与工程， 2009， 博士

【摘要】 计算机和网络技术的迅速发展,加快和深化了社会信息化进程,也使得组织与信息系统的关系日益紧密。随着经济运行节奏的加快,如何对组织内信息系统进行有效整合,并使其快速适应外部环境变化,及时满足客户不断变化的需求,从而在激烈的竞争环境中保持信息优势,成为众多组织在信息化建设中面临的严峻挑战。在开放的网络环境中,使用服务对异质应用和数据资源进行封装、使用服务组合快速构建跨组织的复杂应用,成为近年来分布式计算技术的主流趋势,组合服务也成为开放网络环境下跨组织应用的重要构建形式。在这样的背景下,研究组合服务演化方法对于提高组织应用的环境适应能力具有深远的意义。本文以语义Web环境下的组合服务为研究对象,系统地分析了组合服务演化所面临的各项挑战,重点对语义Web环境下组合服务结构化演化方法进行了研究,并以机器辅助处理为目标,对组合服务演化过程中所涉及的关键技术进行了深入分析,包括组合服务演化需求形式化表示方法、服务描述语法一致性维护和服务描述语义一致性分析等。本文的主要工作包括:1.语义Web环境下组合服务结构化演化方法研究:组合服务演化是组合服务生命周期中变化管理的重要组成部分。在面对复杂组合服务应用时,组合服务演化通常是一项比较复杂的工作。本文以采用OWL-S语言描述的组合服务为研究对象,系统地提出了一种语义Web环境下组合服务演化方法EM4CS。EM4CS方法将组合服务演化周期划分为六个阶段、12个子过程,首先指导知识工程师从问题域获取演化需求,然后以演化本体为基础将上述需求形式化表示为维护请求脚本。在维护请求脚本的驱动下,EM4CS方法以迭代求精的方式逐步完成服务描述的语法和语义一致性维护,在演化结果确认后,将演化结果发布与传播,使依赖于该组合服务的相关应用和运行实例能够同步这些变化,从而保持全局应用的一致性。2.基于演化本体的组合服务演化需求形式化表示方法研究:演化需求形式化表示是使机器理解知识工程师演化意图、并实现辅助处理的基础。本项工作首先依据OWL-S语法规范对语义Web服务的核心概念进行结构化定义,提出了一个面向该核心概念的完备的基本变化操作集,并对抽象层次更高的组合变化操作进行定义。然后,提出了一种演化本体(Evolution Ontology)对这些变化操作、变化间的关系以及关系推导规则进行严格定义。以演化本体为基础,本文采用针对服务描述的维护请求对演化需求进行形式化表示,该请求由正向变化集PCL和否定变化集NCL组成,前者表示服务描述修改目标,而后者表示演化过程中的约束条件。最后,在演化本体的支持下,本文通过推理分析演化需求中潜在的冲突,使后续的组合服务演化效率得到提高。3.提出了一种OWL-S服务描述语法一致性检测与辅助维护方法:首先依据OWL-S语法规范对服务描述语法一致性约束进行枚举分析,然后给出了OWL-S服务描述语法一致性检测方法。为了使机器能够辅助知识工程师对语法不一致进行消解,本文对语法不一致消解策略进行了分析,同时使用消解策略配置向量来表示知识工程师对于语法不一致消解的定制需求。最后,本文提出一种OWL-S服务描述语法一致性辅助维护算法SCMA,该算法将维护请求脚本的实施和服务描述语法一致性检测与修复这两个过程统筹考虑,通过迭代尝试获取可行的语法一致性维护方案。4.提出了一种OWL-S服务描述语义一致性分析方法:本文将组合服务的语义一致性划分为数据语义一致性和过程语义一致性两个部分,前者主要对数据流中源、目标参数概念类型的包容性进行分析,而后者则对服务聚合逻辑进行验证。本文提出了两种方法分析OWL-S服务描述数据语义一致性,即基于推理的方法和基于概念相似度计算的方法。前者通过推理算法发现数据流源、目标参数概念类型间严格的包容关系;后者通过计算概念间的相似概率为知识工程师提供决策依据。本文提出了一种过程模型网(PM_net)对过程模型进行建模,将服务描述过程语义一致性分析问题转化为对应PM_net的可靠性验证问题,并提出了一种基于可覆盖性图的PM_net可靠性验证算法PSA_CG,对OWL-S服务描述的过程语义一致性进行分析。最后,本文给出了PM_net的化简规则,并以PSA_CG算法检测结果为基础,对服务过程模型中逻辑错误的定位方法进行了说明。5.基于上述EM4CS方法及关键技术的研究,设计和实现了遵循EM4CS方法的组合服务演化支撑原型系统ESS4CS,并以电子交易组合服务为例,应用EM4CS方法并借助ESS4CS系统对该组合服务进行演化,从而进一步验证了EM4CS方法的可行性和有效性。综上所述,本文的工作系统地提出了一个语义Web环境下组合服务结构化演化方法,并对其中所涉及的关键技术进行了深入研究,对于提高组织中组合服务应用对于环境的适应能力具有一定的理论价值和应用价值。更多还原

【Abstract】 With the rapid development of computer and network technology, the information process of this society is accelerated and deepened; the organization and information systems are also becoming more and more related. With the speeding up tempo of economy, the problems such as how to carry out effective integration of information systems in organization and make it adaptive with the changes in external environment, how to meet fast-changing customer requirements timely so as to keep information superiority in fierce competition environment, have become severe challenges in the information construction of many organizations. In recent years, the use of services to encapsulate heterogeneous application and data resources, while using service composition to build complex application inter-organization, has become the prevailing trend in distributed computing technology, and the composite services become an important form in the construction of cross-organization applications. In this background, the research on evolution method of composite services has far-reaching significance for improving the ability of applications to adapt with external changing environment.Taking composite services in semantic web environments as research object, the challenges in composite service evolution are analyzed systematically in this dissertation. The structural evolution method of semantic web services (SWS) is introduced in this dissertation, then, to realize automatic assistant process in the evolution cycle, several key technologies are studied, such as formalization of composite service evolution requirements, syntactic consistency maintenance of service description, and semantic consistency analysis of OWL-S service description. The main contributions of this dissertation are as follows:(1) Research on the structural evolution method of composite services in semantic web envrionment. Composite service evolution is an important component of change management in composite service life cycle, and it is usually a complicated job to evolve composite service when face to complex applications. In this dissertation, a semantic web service evolution method EM4CS is introduced, which take SWS described by OWL-S ontology as research object. EM4CS divide the composite service evolution process into 6 stages and 12 sub-processes. First, EM4CS will guide knowledge engineerer (KE) to obtain evolution requirements from problem domain, and then these requirements will be formalized as Maintenance Request Script (MRS) on the basis of Evolution Ontology (EO). On the driven of MRS, the syntactic and semantic consistency maintenance will be finished in an iterative refined way. After the evolution results are confirmed, these results will be published and broadcasted, so that, the related applications and running instances can synchronize former changes, and global application consistency should be realized.(2) Research on formal representation of composite service evolution requirements based on Evolution Ontology (EO). The formal representation of evolution requirements is the base of EM4CS, which make evolution intentions of KE understandable by machine. In this work, the core concepts of SWS are defined according to the OWL-S syntactic specification, and a complete basic change operation set which orient to these core concepts is introduced, while composite change operations in higher abstract layer are also defined. Then, an Evolution Ontology is introduced to define such change operations, relations between these changes and inference rules of these changes formally. On the basis of EO, the evolution requirements are formally represented by concept Maintenance Request (MR) on service description. MR is composed of positive change list (PCL) and negative change list (NCL), the former represent goals of service description modification, while the latter represent the constrain conditions in the process of composite service evolution. At last, in the support of EO, the potential conflictions in MR can be found through reasoning method, so that the efficiency in follow-up stages of composite service evolution can be improved.(3) Research on the method to check and maintain the syntactic consistency of OWL-S service description. In this work, the syntactic consistent constraints are defined formally according to OWL-S syntactic specification, and then a method to check syntactic consistency of OWL-S service description is given. So as to resolve syntactic inconsistency on the aid of machine, the inconsistency resolving strategies are analyzed in this paper, and a resolve strategy configuration vector is proposed to represent the private inconsistency resolving requirement of KE. At last, an algorithm named SCMA is proposed to obtain the available syntactic consistency maintenance plan. In SCMA, the processes of implementation of maintenance request script and maintenance of syntactic consistency of OWL-S service description are considered together, so that, the available maintenance plan will be constructed in an iterative way.(4) Research on the technology to analyze semantic consistency of OWL-S service description. In this dissertation, semantic consistency of composite service is divided into two types, i.e. data semantic consistency and procedural semantic consistency, the former analyzes the inclusions between concept types of source and destination parameters in dataflows; the latter mainly validates the composite logics in composite SWS. In this work, two methods are introduced to analyze data semantic consistency of OWL-S service description, i.e. method based on reasoning and method based on similarity computation of concepts. The former method can find out strict inclusion relation between concept types of source and destination parameters in dataflows, while the latter method can provide decision foundations through computing similarity probability between concepts. To analyze procedural semantic consistency, an extended petri net, which called Process Model Net (PM_net), is intorduced to model the process model of OWL-S service description, and the analysis of procedural semantic consistency is transformed into the soundness validation of underlying PM_net. Then, a PM_net soundness validation algorithm PSA_CG which based on analysis of coverability graph is presented to validate the procedural semantic consistency of OWL-S service description. At last, the reduction rules of PM_net and method to locate logic errors in OWL-S process model are depicted.(5) Based on the research of above-mentioned EM4CS methodology and key technologies, a composite service evolution support system ESS4CS that follow EM4CS is designed and realized. Then, an electronic trading service is taken as example to illustrate how to use EM4CS and ESS4CS system to evolve composite service, so the feasibility and effectiveness of EM4CS is further verified.To sum up, this dissertation presents a structural composite service evolution method in semantic web environment systematically, and researches on the key technologies involved. We believe that our contributions make a nice groundword for future research and engineering on improving the adaptability of composite service applications in dynamic environments.更多还原