A Study On Acquisition And Recommendation Technologies Of Services Behavior Pattern Oriented Services Substitution

With the development of the web service and SOC (Service Oriented Computing), the designing, implement, maintain and usage of the web service composition system have changed mostly. The user can assemble a composite service that satisfies a desired set of requirements by service modeling, selection and composition. Considering a scenario where in one service of a composite service which relies on the pre-existing services becomes unavailable for the service provider of the service chooses not to offer it any more or update it (e.g., by adding/removing some of services'features). Identifying a service which can substitute for the unavailable one has become an important problem in service-oriented computing.Many researches have been done to select services to substitute for unavailable service. But all the basis of the methods mentioned is the static service description provided by the web service provider or presumed by the users. But in the real web service composition system, the static service description cannot describe the function and performance of the web service in dynamic environment for the web service provider cannot predict the executive environment (e.g. transmission rate of the network and server load) which the web service will run in. The existing solutions to substitutive service selection are not satisfied the requirement of the substitutive service selection in dynamic environment. To support the substitutive service selection in dynamic environment, a new framework for web service substitution with a web service description model is required.To solve this problem, SBP (Service Behavior Pattern), which consists of the data message interactive model that represents the executive behavior, executable business environment set that represents the executive business environments and performance functions that show the executive performance of the web service in dynamic environment, is proposed to describe the executive characters of the web service. Based on SBP, an approach, named as SS-SBPA, is proposed in this dissertation. The approach acquires the SBP oriented service substitution by mining the web service log, which is generated by a web service composition system. And a service substitutive framework based on the SS-SBPA is also given. Analyzing the characters of the service substitution, the definition of executive environmental adaptability is proposed. The executive environmental adaptability is the basic to examine the environmental adaptability of a service. The dissertation does research mainly in some aspects as follows:context, format and rules of the web service log, a mining algorithm for weighted sequential pattern and an evaluation index system of the executive environmental adaptability.First, to measure the substitutability of the service, this dissertation defines the concepet SBP (Service Behavior Pattern) by analyzing the semantic information of the service interaction. A framework, named as SS-SBPA, which acquire the service behavior pattern by mining the web service log is proposed. And a service substitutive framework based on SS-SBPA is also proposed. Here, the executive environmental adaptability measures the substitutability directly.Second, aiming at the requirements and characters of the service substitution, the formats of web service log and web service physical environment log are designed in this dissertation. By analyzing the context of the web service log, the rules relative to the service substitution are given. The rules show the relative knowledge hiding in the web service log. And the rules are the key facts to measure the important degree of the message/service in the message exchange sequence/service sequence.Third, to acquire the service behavior pattern, a service behavior pattern acquision method, which getting the SBP by analyzing the components of the service behavior pattern, studying the function, character and acquision method of the function and character, is proposed. One can obtain the service behavior pattern easily by using this method.Fourth, to sovle the problem that different items have different important degree in the sequential pattern mining, a mining algorithm for weighted sequential pattern based on minimum weighted support is proposed. Using this algorithm here, the message exchange sequence and service sequence with high stable should be obtained.Fifth, aiming at the assessing problem of the executive environmental adaptability, an evaluation index system of the executive environmental adaptability is proposed. The system assesses the adaptability by analyzing the acquirsition method of compatibility of substitutive service with the business environment and the prediction of the web service performance. The executive environment adaptability recommends factor, which is calculated by the evaluation index system of the executive environmental adaptability, can measure the performance and the usability of the service effectively.Sixth, to verify the effective and usability of the acquisition and recommendation technologies of service behavior pattern oriented services substitution, an experimental simulation environment for simulating substitutive selection is designed and implemented. And a selection method to select the substitutive service based, on the recommendation of service behavior pattern is designed and, implemented. The experiment showed that applied the result of SS-SBPA in the process of service substitution was effective. And the performance should be increased with the increasing of web service log'scale.