Research On Key Technologies Of Automated Web Service Composition In Networked Manufacturing

In order to exploit and upgrade the connotation and advantage of networked manufacturing, differing from the traditional method in which data are shared and transfered among allied enterprises, the dissertation aims at achieving the dynamic and seamless integration among business entities through interaction and collaboration among computer systems, business applications and software components. Web service, as the software component of networked manufacturing, makes the composition of applications of networked manufacturing equals the compostion of web services. Yet, with the increase of web services, it will be more and more dificult and unpractical to search and compose web services manually, meanwhile, the characteristic of networked manufacturing makes it different from other traditional manufacturing mode, more interaction among softwares and less interference by people are required, so naturally, automoted web service composition becomes the necessary requirements and unlackable contents for constructing and running networked manufacturing.Based on the above background, in order to realize automoted web service composing in networked manufacturing, several key technologies such as web service description, web service function matching, web service composing method, web service composition selection and web service composing platform are researched in the dissertation. The main work and achievements are listed as follows:1. One Metal Model for Web service description M4WEB is proposed under the support of ontology. The model is grounded on WSDL description of web services, on the basis, some extra information such as web service primary information, performance information, functional information and semantic information are supplemented. The model answers the problems that must be resolved to accomplish web service automoted composing, they are:'what the web service does?','how the web service does?','how to get the web service?'and'how to use the web service?'. The model is structally composed of 5 parts: ServiceOutline, ServiceProcess, WSDLDescription, WSDLMapping and ServiceOntologyLink. The model is on the basis of WSDL which makes it convenient to use large numbers of WSDL-described web services, and also the use of ontology enables the web services identifical each other. The model could be used to describe both web services and web service requirements, and the detailing degree can be adjusted according to the accutal requirements.In order to be processed by computer, the model formalization is suceessionly studied. In the section, the requirements for formalization language is firstly proposed, with that, several formalization languages are studied and analyzed, after this, OWL DL is selected as the proper language to formalize the model. Consequently, the detailed formalization method are designed and presented. In the method, general formalization and reference formalization are distinguished in order to deal with the actual problems such as web service individuality, different detailing degrees and detailing emphases, which makes the formalization method more flexible as well as pattern-fixed.2. Two types of function matching are distinguished according to the composing process: the matching between R and S called MR-S and the matching between S and S called MS1-S2, in accordance with this, two methods that based on service interface are proposed respectively. According to the characteristics of web service interfaces, web service interface parameters are decomposed and firstly grouped and matched by types, if the matching degree is satisfied, parameters name and value or value domain matching will be continued in turn.Based on the semantic and logical relationships among the matched parameters, four matching degrees are regulated as well as the corresponding matching rules, which bring much adaptability and flexibility to the methods.3. One directed flood-based composing method is proposed. In the method, the advantages that rapid and convenient message transfering and resource searching of traditional flood algorithm are taken into account, the P/E conflict-checking and the composition nodes repeatition-checking are used as the constraints to direct the composing path, thus, the disadvantages that uncontrolled transfering and repetition of traditional flood algorithm are eliminated, and the closed circulation trap is therefore avoided. In the method, DFS (Deepth First Searching) idea is used to iterate searching the first node that is marked UNKNOWN on the composing tree, which ensures the full cover of composing tree branches.4. Some principles that used for web services to select and regulate nonfunctional conditions are proposed. Especially, due to the importance of QoS (Quality of web Service), one web service quality rating system that with QoS trend is constructed, and whit this, a QoS rating mechanism and method is proposed under the support of weighted average method and three-point method. The method is relatively practicable easily to use, which makes QoS rating no longer inefficient and unscientific.After analyzing and making clear the nonfunctional conditions, one nonfunctional condition-based web service composition selection method is developed on the basis of extension and supplementarity to the Fuzzy Analytic Hierarchy Process (FAHP). The method employs FAHP to computer the weight factors of nonfunctional conditions, and determines the conditions'weight number based on the expectation distance and hereby constructs the goal function. In the method, dimensionless functions and correction formulae are constructed to eliminate and correct the errors that arise from the differences of dimensions and the inconsistency of expectation distance scale, which makes distinct nonfunctional conditions comparable.5. One web service composing prototype system ComWS-DEB is designed and developed. The system is aimed at the automated composing of web services in the networked manufacturing environment. ComWS-DEB is structlly divided into four layers: Gallery Layer, Resource Gate Layer, Portal Layer and Composition Layer, which is not only clearly consistent with above key technologies, but also is easily realized with currently popular module design idea. The system is functionally composed of two parts: registration&description and composing&selection. The two parts use and cover the above research outcomes.Finally, one RP (Rapid Protoype) example runs through and illustrates the protype system. The running result shows that the prototype system and the research outcomes are primarily correct. To sum up, several key technologies of accompolishing networked manufacturing such as web service description, web service function matching, web service composing, web service composition selection and web service composing prototype system are discussed and researched in the dissertation, and correspondingly, some primarily-evaluated solutions are proposed. This research is of theoretical and practicable values and is helpful to accomplish the goal of networked manufacturing.