Dynamic Service Discovery, Composition and Reconfiguration in a Model Mapping Business Process to Web Services

In any organization where SOA has been implemented, all of the web services are registered in UDDI and users’ needs are served by using appropriate web services. So in this paper, we will try to discover a service from repository first that can provide the required output to the user. The process becomes difficult when a single service is not able to fulfill a user’s need and we need a combination of services to answer complex needs of users. In our paper, we will suggest a simpler approach for dynamic service composition using a graph based methodology. This will be a design time service composition. This approach uses the functional and non-functional parameters of the services to select the most suitable services for composition as per user’s need. This approach involves “service classification” on the basis of functional parameters, “service discovery” on the basis of user’s need and then “service composition” using the selected services on the basis of non-functional parameters like response time, cost, security and availability. Another challenge in SOA implementation is that, once the composition has performed, some services may become faulty at runtime and may stop the entire process of serving a user’s need. So, we will also describe a way of “dynamic service reconfiguration” in our approach that will enable us to identify and replace a faulty service that is violating the SLA or is not accessible anymore. This service reconfiguration is done without redoing or reconfiguring the entire composition. In the end, to simulate the proposed approach, we will represent a prototype application built on php 5.4 using My SQL database at backend.

Typed formal model for WS-CDL specification of web services composition

In order to formally reason and verify web services composition described by web services choreography specification WS-CDL,a typed formal model named typed Abstract WS-CDL（web services choreography description language）for WS-CDL specifications is proposed.In typed Abstract WS-CDL,the syntax of type and session,typing rules and operational semantics are formalized;the collaborations of web services are formally described by sessions;the operational semantics of a session can help to formally reason the execution of the choreography;the typing rules can help to formally check the data type consistency of exchanged information between web services and capture run-time errors due to type mismatches.Particularly,the concepts of type assumption set extension and type assumption set compatibility are proposed,and the merging algorithm of type assumption sets is defined so as to eliminate type assumption conflict.Based on the formal model,typed mapping rules for mapping web services choreography to orchestration is also defined.With the typed mapping rules,orchestration stubs and their type assumption sets can be generated from a given choreography; thus, web services composition can be verified at choreography and orchestration levels,respectively.The model is proved to have properties of type safety,and how the model can help to reason and verify web services composition is illustrated through a case study.

Web services composition with QoS bound based on simulated annealing algorithm

In order to enable quality-aware web services selection in the process of service composition,this paper first describes the non-functional requirements of service consumers and the quality of elementary service or composite service as a quality vector,and then models the QoS（quality of service）-aware composition as a multiple criteria optimization problem in extending directed graph.A novel simulated annealing algorithm for QoS-aware web services composition is presented.A normalizing for composite service QoS values is made,and a secondary iterative optimization is used in the algorithm.Experimental results show that the simulated annealing algorithm can satisfy the multiple criteria and global QoS requirements of service consumers.The algorithm produces near optimum solution with much less computation cost.

Web services selection based on semantic similarity

Services discovery based on syntactic matching cannot adapt to the open and dynamic environment of the web. To select the proper one from the web services candidate set provided by syntactic matching, a service selection method based on semantic similarity is proposed. First, this method defines a web services ontology including QoS and context as semantic supporting, which also provides a set of terms to describe the interfaces of web services. Secondly, the similarity degree of two web services is evaluated by computing the semantic distances of those terms used to describe interfaces. Compared with existing methods, interfaces of web services can be interpreted under ontology, because it provides a formal and semantic specification of conceptualization. Meanwhile, efficiency and accuracy of services selection are improved.

A Service Design Oriented Web Services Composite Platform

In order to realize flexible, adaptable, extensible, efficient, and user-friendly service composition, we propose a service design oriented Web Service composite platform （SDOWSCP） and a service composition mechanism called composed-service-requestor-orient ed service composition （OBSDOSC）. SDOWSCP imports ontology into UDDI to define and annotate services in a flexible and intuitive manner and employs a concept of bond as a solution to the process heterogeneity. OBSDOSC is proposed in order to do some efforts to overcome some defects which current design tools usually have such as not user friendly and too professional. This paper proposes a pattern which describes the basic features of semi-automatic composite mode, discusses the whole lifetime of composed service and highlights how to lessen the descriptive heterogeneity and process heterogeneity and how to facilitate the design of composing a service.

A Testing Method for Web Services Composition Based on Data-Flow

This paper proposes a method of data-flow testing for Web services composition. Firstly, to facilitate data flow analysis and constraints collecting, the existing model representation of business process execution language （BPEL） is modified in company with the analysis of data dependency and an exact representation of dead path elimination （DPE） is proposed, which over-comes the difficulties brought to dataflow analysis. Then defining and using information based on data flow rules is collected by parsing BPEL and Web services description language （WSDL） documents and the def-use annotated control flow graph is created. Based on this model, data-flow anomalies which indicate potential errors can be discovered by traversing the paths of graph, and all-du-paths used in dynamic data flow testing for Web services composition are automatically generated, then testers can design the test cases according to the collected constraints for each path selected.

Android Web Services应用研究

该文介绍了在Android平台下如何使用ksoap2库来实现Web Services的功能,并介绍了Android的消息机制,及如何通过Handler来实现异步UI更新。

Analysis and modeling of web services flow using π-calculus

In order to increase the effectiveness and the reliability of web services flow, the ~r-calculus formal method is introduced as a development language for web services flow. The π-calculus overcomes inabilities of web service flow languages in demonstrating the consistency, validating the correctness and so on. The π- calculus analysis and modeling of web services flow is presented, the dynamic actions and basic activities of WS-BPEL with π-calculus formally are described, and the mapping from π-calculus expression to WS-BPEL is built. The basic construction of web services flow with the π-calculus method after the analysis of the syntax of WS-BPEL and inter-description between WS-BPEL and π-calculus is expressed. Also discussed are the approaches to web services flow by modeling from different views, and the proposed approaches through the development and modeling of an e-commerce web service flow application are illustrated.

MANUFACTURING SERVICE SYSTEM BASED ON WEB SERVICES FOR PARALLEL KINEMATICS MACHINES

Parallel kinematics machine （PKM） is advantageous over the serial machine tools in processing the complex-surface products. A manufacturing service system for PKM is developed to provide the services of the complex-surface machining for potential geographically-dispersed manufacturing enterprises. In order to easily in- tegrate the external system, Web services are used to encapsulate post-processing functions of PKM legacy sys- tems, including compilation, workspace calculation, interfere calibration, and kinematics transformation. A ser- vice-oriented architecture（SOA） is proposed for the cooperative work between the PKM system and its client. The workflow and the function module of this manufacturing service system are presented. An example shows that as a result of SOA and loose coupling, such a Web service-based manufacturing service system is easier to in- tegrate and interoperate with its client. Meanwhile, the system decreases the manufacturing cost and improves the efficiency than its former kind of distributed system.

基于Web Services的高校教学质量监控系统的分析与设计

结合目前高校教学管理的形势,将软件的开发结构B/S和C/S结合在一起,利用当前流行的开发工具和先进的技术设计基于Web Services的教学管理质量监控系统。把本系统柔和到校园网里,针对不同的对象把功能分别放在局域网和广域网中。

基于Web Services的校园教学资源整合的研究

针对高校信息化建设过程中普遍遇到的异构平台资源共享的问题,提出了一种基于Web services的教学资源整合框架。同时还介绍了Web Services的应用体系结构、相关技术和基于XML的教学资源描述方法。

Multi-attribute group decision making algorithm for web services selection based on QoS

To address the problem of web services selection based on quality, an approach of multi-attribute group decision making algorithm is proposed. Based on the Borda social choice function, the group decision making algorithm aggregates the results of multiple methods with different principles which are used to obtain constantly changing quality of service, thus increasing the confidence to select the most appropriate web service for a special task. The experimental results indicate that the proposed approach has better scalability and can be applied to large-scale distributed service computing environments. It is also shown that the proposed group decision making approach can effectively optimize the services selection and outperforms the random and robin policies. By using this approach, it can extend a method to obtain constantly changing quality of service and construct a synthetic information entity with multi-level knowledge, which guarantees the accuracy of services selection.

基于Web Services技术的分布式在线销售系统的开发与实现

基于Web Services的分布式计算系统的体系架构,利用Web Services与JZEE等技术,以Online Shopping为实例,开发了一个分布式应用系统,并验证了设计的Online Shopping实例的全部功能均可正常运行.该系统提供Web用户界面,具备诸如用户登记、商品目录与商品浏览等服务功能,便于消费者调用系统的内部Web服务的业务功能,通过Online Shopping的响应,获取所需的产品信息,并储存在数据库中.此外,Online Shopping也可以调用供应商的Web服务,将满足要求的订单发给供应商,从而实现产品供应商与自身系统之间的自动化的系统集成.

基于Web Services数据交换的测绘违法行为监管系统设计与实现

测绘违法监管随着社会发展和城市建设日益受到重视,监管难度同时也日益加大。该文以天津市测绘违法行为监管作为研究对象,在天津市规划局一网通平台基础之上,基于Web Services数据交换共享技术,以信息化的手段构建了一个以实现测绘违法行为查处工作的信息化为目的的测绘违法行为监管系统,设计了系统主要功能实现的流程,探讨了关键技术,综合采用数据库技术、网络技术、办公自动化技术、工作流技术和Web Services数据交换技术,以.NET为平台,开发了测绘违法行为监管系统。系统实现了测绘违法行为查处程序的规范化和测绘违法行为查处工作的信息化。该系统在天津市规划局执法总队成功应用,运行结果表明提高了测绘违法监管的管理水平和工作效率,有效缓解了监管难度日益增大的问题。从信息技术的角度,基于Web Services技术解决了系统与天津市规划局一网通平台进行数据交换共享的问题。

Capability matchmaking of semantic web services with preconditions and effects

In order to solve the problem that the current matchmaking methods for semantic web service mainly focus on the matchmaking of IO （inputs, outputs） descriptions which may result in one-sidedness, a description-logic-based IOPE （inputs, outputs, preconditions, effects） description and matchmaking method is proposed for semantic web service. The description logic concept is used to annotate service IO and the description logic assertion is employed to describe service PE（preconditions, effects）. TBox subsumption checking is used to measure the subsumption relationship between IO descriptions of service request and advertising; ABox consistency checking is used for checking the logical implication between PE descriptions of service request and advertising. Based upon the logical implication, four kinds of PE matching degrees are proposed to measure and compare the pros and cons of the results of matchmaking. They are the exact, perfect, side-effect and common match. Experiments show that the method has a higher precision rate under the same recall rate compared with the existing method.

An Adaptive Trust Model of Web Services

This paper proposes a dynamic Web service trust (WS Trust) model, and somecorresponding trust metric evaluation algorithms. The main goal is to evaluate the trustworthinessand predict the future bchaxiors of entities in oeder to help users find trustworthy Web serviceproviders and prevent users from providing unfair ratings against service providers.

Dynamic services selection algorithm in Web services composition supporting cross-enterprises collaboration

Based on the deficiency of time convergence and variability of Web services selection for services composition supporting cross-enterprises collaboration,an algorithm QCDSS(QoS constraints of dynamic Web services selection)to resolve dynamic Web services selection with QoS global optimal path,was proposed.The essence of the algorithm was that the problem of dynamic Web services selection with QoS global optimal path was transformed into a multi-objective services composition optimization problem with QoS constraints.The operations of the cross and mutation in genetic algorithm were brought into PSOA(particle swarm optimization algorithm),forming an improved algorithm(IPSOA)to solve the QoS global optimal problem.Theoretical analysis and experimental results indicate that the algorithm can better satisfy the time convergence requirement for Web services composition supporting cross-enterprises collaboration than the traditional algorithms.

基于Web Services的分布式信息管理系统设计与实现

Web Services技术是分布式计算技术的革命性创新,该文通过对该技术的体系结构和关键技术的分析,把Web Services技术运用到考务管理系统中,有效解决了学生、教师信息分散、重复维护、信息不能实时共享的难题。

Immune Algorithm for Selecting Optimum Services in Web Services Composition

For the problem of dynamic optimization in Web services composition, this paper presents a novel approach for selecting optimum Web services, which is based on the longest path method of weighted multistage graph. We propose and implement an Immune Algorithm for global optimization to construct composed Web services. Results of the experimentation illustrates that the algorithm in this paper has a powerful capability and can greatly improve the efficiency and veracity in service selection.

Building GIS Web Services on JXTA Network

In recent years, Web services and Peer-to-Peer (or simply P2P) appear as two of the hottest research topics in network computing. On the one hand, by adopting a decentralized, network-based style, P2P technologies can make P2P systems enhance overall reliability and fault-tolerance, increase autonomy, and enable ad-hoc communication and collaboration. On the other hand, Web services provides a good approach to integrate various heterogeneous systems and applications into a cooperative environment. This paper presents the techniques of combining Web services and P2P technologies into GIS to construct a new generation of GIS, which is more flexible and cooperative. As a case study, an ongoing project JGWS is introduced, which is an experimental GIS Web services platform built on JXTA. This paper also explores the schemes of building GIS Web services in a P2P environment.