Although the benefits of reusing services have been widely acknowledged, composing existing services to realize different user requirements is still a difficult and time consuming task. There have been research works on workflow templates and service design patterns that offer a higher level of reuse and assist in the composition process. Yet existing workflow templates are too specific and service design patterns may be too abstract and their effectiveness in assisting the composition process may be limited. In this dissertation, we propose a comprehensive service pattern model that is more flexible than existing workflow/service templates while allowing systematic instantiation into some concrete workflows. The service pattern supports flow control, abstract services, and prospect services (similar to a node in a design pattern). Also, we develop a set of reasoning rules to automatically verify and determine the assignment of instantiation parameters in service pattern. In addition, recent research into automated Web service composition focuses on control flow specification and enforcement. Traditionally, message mismatch between Web services appears as an orthogonal problem that can be solved using XML-based query languages. This study instead considers Web service composition and message manipulation holistically to support greater optimization of Web service composition. A proposed model, the WS-data model, focuses on data exchanges in composing Web services. Several operators with varying properties can be used to compose Web services and manipulate their input and output data. Experiments conducted on the Amazon Cloud platform show that these operators¡¦ properties can be used to develop a more efficient way for realizing a complex task, expressed according to the proposed WS-data model. It is hoped that the proposed models and automated reasoning of instantiation parameters assignment will realize the benefits of SOA in the real business settings.

As the Web Services proliferate and complicate it is becoming an overwhelming job to manually prepare the Web Service Compositions which describe the communication and integration between Web Services. This thesis analyzes the usage of Event Calculus, which is one of the logical action-effect definition languages, for the automated preparation and execution of Web Service Compositions. In this context, planning capabilities of Event Calculus are utilized. Translations from Planning Domain Description Language and DARPA Agent Markup Language to Event Calculus are provided to show that Web Services can be composed with the help of Event Calculus. Also comparisons between Event Calculus and other planning languages used for the same purposes are presented.

O teste de programas concorrentes é essencial para assegurar a qualidade das atuais aplicações distribuídas/paralelas em desenvolvimento. Apesar de ser essencial, essa atividade de teste é dificilmente empregada adequadamente, devido a fatores como: alto custo de execução, grande lacuna entre desenvolvedores e resultados de pesquisas em testes para programas concorrentes e acesso às ferramentas de teste de programas concorrentes que automatizem/viabilizem o emprego do teste. Este projeto visa definir os parâmetros da atividade de teste estrutural de programas concorrentes que nortearão a composição de diferentes serviços na Web. Tais serviços dão suporte à atividade de teste estrutural de programas concorrentes, estabelecendo fronteiras claras em ferramentas de teste para os módulos relativos ao modelo de teste, aos critérios de teste, à linguagem de programação e aos paradigmas de sincronização. Desse modo, novas ferramentas de teste poderão ser construídas de maneira mais flexível, com menos custo de desenvolvimento e com mais eficácia. Tal abordagem traz como benefícios diretos: (1) facilitar a interação entre os setores da indústria, ensino e pesquisa que estejam interessados no desenvolvimento de programas concorrentes com qualidade; (2) diminuir os custos de instalação e manutenção de ferramentas de teste estrutural pelos desenvolvedores; (3) facilitar a incorporação da atividade de teste de programas concorrentes no ciclo de desenvolvimento das aplicações distribuídas e paralelas; (4) aumentar a abrangência do projeto TestPar, permitindo que novos usuários (desenvolvedores, professores e outros grupos de pesquisa) possam utilizar facilmente os conhecimentos gerados no projeto; e (5) realimentar o projeto TestPar com novas demandas qualificadas, estas advindas de novos programas concorrentes submetidos para teste. / Testing of concurrent programs is essential to ensure the quality of todays distributed/parallel applications in development. Although it is essential that testing activity is hardly properly employed, due to factors such as high cost of implementation, big gap between developers and research results in tests for competing programs and access to competing software testing tools to automate / enable the test job. This project aims to define the parameters of structural testing activity of concurrent programs that will guide the composition of different Web services. These services support the structural testing activity of concurrent programs, establishing clear boundaries in test tools for the modules related to the test model, the test criteria, the programming and synchronization paradigms language. Thus, new test tools can be built in a more flexible way, with less development cost and more effectively. Such an approach has as direct benefits: (1) facilitate interaction between industry sectors, education and research who are interested in the development of concurrent programs with quality; (2) reduce the costs of installation and maintenance of structural testing tools for developers; (3) facilitate the incorporation of testing activity of concurrent programs in the development cycle of distributed and parallel applications; (4) increase the scope of TestPar design, allowing new users (developers, teachers and other research groups) can easily use the knowledge generated in the project; and (5) feed back into the project TestPar with new demands qualified, those arising from new concurrent programs submitted for testing.

In recent years, Web services had been widely used on the Internet. Thanks to the convenient communication technologies and their inexpensive cost, communications between organizations is much easier, and Web services have become a de-facto standard for organizations to provide information and services. There are two different perspectives to describe Web service composition: orchestration and choreography. Works that verify a choreography model so as to alleviating some correctness problem such as deadlock have also been proposed. However the verification of implementations based on a choreography model has not be addressed. In this thesis, we propose an approach to verify the conformance of a set of Web services to a given choreography model and prune some candidate Web services which do not comply with the choreography model to avoid discordance with the choreography model and run-time errors. The proposed approach is evaluated by simulating 10,000 execution sequences of composite Web services. The experimental results show that our proposed method improves the performance of success rate and space usage by pruning the unsuitable candidate Web services.

Web services can be broadly classified into two types, namely effect providing (EP) services and data providing (DP) services. In this work, we address DP service composition problem that intends to satisfy user preference specified at the instance level, namely the expected occurrence. We first use the query rewriting method to identify a composition of service types that satisfies user¡¦s requirement and employ Bayesian Network model to express the causal relationship between exchange variables of DP service types. Service selection is then conducted by computing the posterior probability in the Bayesian Network. We conduct experiments to show that our proposed Bayesian Network-based method outperforms the other baseline methods in terms of execution success rate and data quality. It also has reasonable execution time.

Nowadays, Web Services technology has become a standard to integrate business processes across organizations. In general, there are two approaches for web service composition: Orchestration and Choreography. Orchestration is used to develop a single process that integrates services within or across an organization to achieve a business goal. On the other hand, Choreography is often used for cross-organizational communication and serves as a specification for communication. In a choreographed environment, each Web service is an independent entity, and each service selects the partner services using its own selection policy without knowing all the other services in the choreography. In this thesis, we use £k-calculus for modeling the Web Services. Afterwards, we propose an approach for each constituent process to choose and invoke other processes using the limited information provided by its partners. In our method, each service proclaims the requirments of its potential service providers (or consumers) and itself and provides to its partners. Subsequently each service will generate a local view using the information provided by its service consumers and providers to guide the selection. We evaluate our method by simulating 100,000 executions with different degrees of service availability. The experimental results indicate that our proposed method can indeed improve the success rate of the entire choreography.

Web Services are self-contained, self-describing, modular applications that can be published, located, and invoked through XML artefacts across the Web. Web services technologies can be applied to many kinds of applications, where they offer considerable advantages compared to the old world of product-specific APIs, platform-specific coding, and other &ldquo / brittle&rdquo / technology restrictions. Currently there are millions of web services available on the web due to the increase in e-commerce business volume. Web services can be discovered using public registries and invoked through respective interfaces. However how to automatically find, compose, invoke and monitor the web services is still an issue. The automatic discovery, composition, invocation and monitoring of web services require that semantics will be attached to service definitions. The focus of this thesis is on the composition of web services. The approach taken is to extend the DAML-S ontology that is used to define the semantics of services to include the &ldquo / succeeding services&rdquo / for any service provided. These definitions for individual service instances are declared by the service providers. They are presented to the users of the service to construct a workflow in a mobile environment. The workflow generated is represented both graphically in the mobile device and in XML-format as a BPEL4WS document. The aim of this thesis is to prove that it is possible to build a semi-automatic web service composition utility incorporating semantic constructs, using a mobile device. The generated workflow is suitable for deployment on an engine where it can be executed multiple times with different configurations.

O teste de programas concorrentes é essencial para assegurar a qualidade das atuais aplicações distribuídas/paralelas em desenvolvimento. Apesar de ser essencial, essa atividade de teste é dificilmente empregada adequadamente, devido a fatores como: alto custo de execução, grande lacuna entre desenvolvedores e resultados de pesquisas em testes para programas concorrentes e acesso às ferramentas de teste de programas concorrentes que automatizem/viabilizem o emprego do teste. Este projeto visa definir os parâmetros da atividade de teste estrutural de programas concorrentes que nortearão a composição de diferentes serviços na Web. Tais serviços dão suporte à atividade de teste estrutural de programas concorrentes, estabelecendo fronteiras claras em ferramentas de teste para os módulos relativos ao modelo de teste, aos critérios de teste, à linguagem de programação e aos paradigmas de sincronização. Desse modo, novas ferramentas de teste poderão ser construídas de maneira mais flexível, com menos custo de desenvolvimento e com mais eficácia. Tal abordagem traz como benefícios diretos: (1) facilitar a interação entre os setores da indústria, ensino e pesquisa que estejam interessados no desenvolvimento de programas concorrentes com qualidade; (2) diminuir os custos de instalação e manutenção de ferramentas de teste estrutural pelos desenvolvedores; (3) facilitar a incorporação da atividade de teste de programas concorrentes no ciclo de desenvolvimento das aplicações distribuídas e paralelas; (4) aumentar a abrangência do projeto TestPar, permitindo que novos usuários (desenvolvedores, professores e outros grupos de pesquisa) possam utilizar facilmente os conhecimentos gerados no projeto; e (5) realimentar o projeto TestPar com novas demandas qualificadas, estas advindas de novos programas concorrentes submetidos para teste. / Testing of concurrent programs is essential to ensure the quality of todays distributed/parallel applications in development. Although it is essential that testing activity is hardly properly employed, due to factors such as high cost of implementation, big gap between developers and research results in tests for competing programs and access to competing software testing tools to automate / enable the test job. This project aims to define the parameters of structural testing activity of concurrent programs that will guide the composition of different Web services. These services support the structural testing activity of concurrent programs, establishing clear boundaries in test tools for the modules related to the test model, the test criteria, the programming and synchronization paradigms language. Thus, new test tools can be built in a more flexible way, with less development cost and more effectively. Such an approach has as direct benefits: (1) facilitate interaction between industry sectors, education and research who are interested in the development of concurrent programs with quality; (2) reduce the costs of installation and maintenance of structural testing tools for developers; (3) facilitate the incorporation of testing activity of concurrent programs in the development cycle of distributed and parallel applications; (4) increase the scope of TestPar design, allowing new users (developers, teachers and other research groups) can easily use the knowledge generated in the project; and (5) feed back into the project TestPar with new demands qualified, those arising from new concurrent programs submitted for testing.

Web services have become a prominent paradigm for building of both inter and intra-enterprise business processes. These processes are composed from existing Web services based on defined requirements. Standards and techniques have been developed to aid in the dynamic composition of services. However, these approaches are limited when it comes to the handling of unexpected events. This dissertation presents the results of experiments that investigated numerous problems related to Web service composition processes. Based on the investigation, a fault taxonomy was formulated. Faults were grouped into three broad categories, each representing a distinct problem stage. The investigation into faults gave rise to the issue of fault recovery and continued process execution. A list of requirements for self-healing Web service composition was identified, while a new self-healing cycle was exploited based on the MAPE cycle (Monitor, Analyzer, Planner, Executive). The proposed self-healing composition cycle consists of three modules: Plan Generation Module, Plan Execution Module and Failure Analysis Module. The plan execution module, consisting of the execution and run-time monitoring phases, and the failure analysis module, consisting of the analysis and sensemaking phases, were found to be vital to self-healing Web service composition. Self healing Web service composition and the goal of self-healing were achieved through the use of Hierarchical Task Network (HTN) planning systems. / Dissertation (MSc)--University of Pretoria, 2009. / Computer Science / unrestricted

運用語義網本體論來描述網路服務，實現網路服務的自動發現、調用和組合已經被證實是有效的。人工智慧規劃技術就是運用此技術描述網路服務來達到自動化網路服務組合。OWL-S支援使用OWL來描述網路服務的前提與效果，而在OWL的規則描述語言方面，則可以使用SWRL。本論文是以OntoComposer規劃工具為基礎，發展一套前置處理器來簡化其使用，讓使用者不需具備人工智慧規劃描述語言及語義網路服務描述等知識，只要尋找到符合需求之網路服務後，就可以自動轉換成支持條件分支圖規劃器之輸入文件，並在設定目標後進行規劃組合，最後讓組合之複合網路能夠在執行引擎上正確執行。 / Using Semantic Web ontologies to describe Web Services has proven to be effective for automatic service discovery, invokcation and composition. AI planning techniques have been employed to automate the composition of Web Services in this way. OWL-S supports the description of the preconditions and effects of a web service using OWL statements, and SWRL is the language for expressing OWL Rules. OntoComposer is an AI planning based tool for Combining-GraphPlan, an extension for GraphPlan so that supports condition branching. This thesis presents a preprocessor for OntoComposer to simplify its input task so that the user does not have to learn the AI Planning description language and knowledge of the semantic web service description. Just look to meet the demand of web services, our preprocessor will translate them to support branch planning for the input file. After setting the targets the OntoComposer will compose some component web services to a complex web service. Finally, let the composition of web services on the execution engine the correct execution.