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Tesi sul tema "Service composition"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 9 giugno 2025

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Foster, Simon. "A compositional semantic theory for service composition." Thesis, University of Sheffield, 2010. http://etheses.whiterose.ac.uk/1723/.

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Service Composition refers to a popular modern software paradigm for building applications by combining distributed reactive components using the World-Wide-Web as the medium. The approach is characterised by the use of standardised protocols, languages and representations such as XML, which ensures that services are platform agnostic. Whilst the architecture is well understood for simple single-interaction services built in the style of classical procedures from the traditional programming paradigm, much discussion is still taking place with regard to more complicated, fully reactive services, where the consumer interacts in a stateful manner. The aim of this Thesis is to investigate the way in which composite Web services are built, and provide a useful semantic theory for service composition. Inspiration for this comes from several sources, including existing technologies such as WS-BPEL and WSMO, and the workﬂow patterns research, which defines a diverse collection of control-ﬂow patterns which should be provided by a service composition language. My approach to service composition is based on Abstract Timed Process Calculus. Core to this approach is compositionality – a Web service model must be semantically decomposable to allow component manipulation. An Abstract Timed Process Calculus allows elegant modelling of component systems through a variety of synchronisation patterns such as isochronic broadcast. In this work I will seek to advance this area by constructing a novel timed process calculus which seeks to surpass previous calculi. This calculus will form the underlying meta-model for a semantic theory for a service composition language called Cashew-A. The semantic theory will be useful for both verification and execution of composite Web services.

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Fischer, Jeffrey M. "Robust service composition." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1779690531&sid=3&Fmt=2&clientId=1564&RQT=309&VName=PQD.

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He, Qiang. "Lifetime service level agreement management for service composition." Swinburne Research Bank, 2009. http://hdl.handle.net/1959.3/68739.

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Thesis (Ph.D) - [Faculty of Information and Communication Technologies], Swinburne University of Technology, 2009. Typescript. A thesis submitted to [Faculty of Information and Communication Technologies], Swinburne University of Technology for the degree of Doctor of Philosophy. "March 2009". Bibliography: p. 136-141.

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HUANG, Cuiting. "Service composition in converged service environment." Phd thesis, Institut National des Télécommunications, 2012. http://tel.archives-ouvertes.fr/tel-00762644.

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The goal of this thesis is to provide enhanced mechanisms to deploy competitive services in a rapid and cost-effective manner. To achieve this goal, we first propose an automatic service composition model relying on an IMS/Web converged environment. This service composition model is intended to be one in which even non-professional users can easily reuse existing services to create new services. To further improve the automatic service composition feature, three strategies including passive update, active update and hybrid update are proposed and analyzed. We then propose a centralized service exposure framework for a variey of services, including Telecom / Web / Device / user-generated services. This framework aims at enhancing the user-centric and convergence features, and providing the unified access to diverse services.Subsequently, two P2P based service information sharing models are designed to complement the centralized service exposure model : i) A hierarchical P2P based model, which reuses Chord for guaranteeing the service discovery efficiency, meanwhile adopts the concept of abstract service publication and discovery for enabling the ambiguous services searching. ii) A triplex P2P overlay based model, which mainly targets the devices offered services. In this model, we use the gateways to delegate the devices residing in them for the global service exposure, and use a triplex overlay based architecture, which includes an underlying unstructured P2P layer, a Semantic Overlay Network (SON) based overlay and a service dependency overlay, for the service information sharing and discovery

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Huang, Cuiting. "Service composition in converged service environment." Thesis, Evry, Institut national des télécommunications, 2012. http://www.theses.fr/2012TELE0009/document.

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L'objectif de cette thèse est de fournir des mécanismes améliorés pour déployer des services compétitifs par des manières rapides et rentables. Nous proposons un modèle de composition de service basé sur un environnement IMS/Web convergent. Ce modèle permet aux utilisateurs non professionnels de réutiliser les services existants pour créer de nouveaux services facilement. Pour améliorer la fonctionnalité de composition automatique, trois stratégies, y compris mise à jour passive, mise à jour active et mise à jour hybride sont proposées et analysées. Nous introduisons ensuite une plateforme centralisée d'exposition de service pour une variété de services, y compris services de Télécom / Web / appareil / services générés par les utilisateurs. Cette plateforme vise à renforcer les caractéristiques de centrée-sur-utilisateur et convergence, et fournir l'accès unifié à différents services. Par la suite, deux modèles basés sur le P2P sont conçus pour compléter le modèle centralisé: i) Un modèle hiérarchique basé sur Chord pour garantir l'efficacité de la découverte de services. Il adopte le concept de publication et découverte de service abstrait pour permettre à la recherche de service ambiguë. ii) Un modèle de superposition-triplex et P2P basé, qui cible principalement des services offerts par les appareils. Dans ce modèle, nous utilisons des passerelles pour déléguer des appareils résidant en eux pour l'exposition globale de services, et utilisons une architecture basée sur une superposition triplex, qui comprend une couche P2P non structurée, une couche de réseau sémantique (SON), et une couche de dépendance de service, pour la partage de l'information de service et la découverte de services The goal of this thesis is to provide enhanced mechanisms to deploy competitive services in a rapid and cost-effective manner. To achieve this goal, we first propose an automatic service composition model relying on an IMS/Web converged environment. This service composition model is intended to be one in which even non-professional users can easily reuse existing services to create new services. To further improve the automatic service composition feature, three strategies including passive update, active update and hybrid update are proposed and analyzed. We then propose a centralized service exposure framework for a variey of services, including Telecom / Web / Device / user-generated services. This framework aims at enhancing the user-centric and convergence features, and providing the unified access to diverse services.Subsequently, two P2P based service information sharing models are designed to complement the centralized service exposure model : i) A hierarchical P2P based model, which reuses Chord for guaranteeing the service discovery efficiency, meanwhile adopts the concept of abstract service publication and discovery for enabling the ambiguous services searching. ii) A triplex P2P overlay based model, which mainly targets the devices offered services. In this model, we use the gateways to delegate the devices residing in them for the global service exposure, and use a triplex overlay based architecture, which includes an underlying unstructured P2P layer, a Semantic Overlay Network (SON) based overlay and a service dependency overlay, for the service information sharing and discovery

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Huang, Cuiting. "Service composition in converged service environment." Electronic Thesis or Diss., Evry, Institut national des télécommunications, 2012. http://www.theses.fr/2012TELE0009.

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Meyer, Harald, and Dominik Kuropka. "Requirements for service composition." Universität Potsdam, 2005. http://opus.kobv.de/ubp/volltexte/2009/3309/.

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Kuropka, Dominik, and Harald Meyer. "Survey on Service Composition." Universität Potsdam, 2005. http://opus.kobv.de/ubp/volltexte/2009/3378/.

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It is predicted that Service-oriented Architectures (SOA) will have a high impact on future electronic business and markets. Services will provide an self-contained and standardised interface towards business and are considered as the future platform for business-to-business and business-toconsumer trades. Founded by the complexity of real world business scenarios a huge need for an easy, flexible and automated creation and enactment of service compositions is observed. This survey explores the relationship of service composition with workflow management—a technology/ concept already in use in many business environments. The similarities between the both and the key differences between them are elaborated. Furthermore methods for composition of services ranging from manual, semi- to full-automated composition are sketched. This survey concludes that current tools for service composition are in an immature state and that there is still much research to do before service composition can be used easily and conveniently in real world scenarios. However, since automated service composition is a key enabler for the full potential of Service-oriented Architectures, further research on this field is imperative. This survey closes with a formal sample scenario presented in appendix A to give the reader an impression on how full-automated service composition works.

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Vuković, Maja. "Context aware service composition." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612751.

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Pino, Luca. "Security aware service composition." Thesis, City University London, 2015. http://openaccess.city.ac.uk/13170/.

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Security assurance of Service-Based Systems (SBS) is a necessity and a key challenge in Service Oriented Computing. Several approaches have been introduced in order to take care of the security aspect of SBSs, from the design to the implementation stages. Such solutions, however, require expertise with regards to security languages and technologies or modelling formalisms. Furthermore, existing approaches allow only limited verification of security properties over a service composition, as they focus just on specific properties and require expressing compositions and properties in a model based formalism. In this thesis we present a unified security aware service composition approach capable of validation of arbitrary security properties. This approach allows SBS designers to build secure applications without the need to learn formal models thanks to security descriptors for services, being they self-appointed or certified by an external third-party. More specifically, the framework presented in this thesis allows expressing and propagating security requirements expressed for a security composition to requirements for the single activities of the composition, and checking security requirements over security service descriptors. The approach relies on the new core concept of secure composition patterns, modelling proven implications of security requirements within an orchestration pattern. The framework has been implemented and tested extensively in both a SBS design-time and runtime scenario, based respectively on Eclipse BPEL Designer and the Runtime Service Discovery Tool.

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Al, Ridhawi Yousif. "Dynamic Composition of Service Specific Overlay Networks." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24011.

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Content delivery through service overlay networks has gained popularity due to the overlays’ abilities to provide effective and reliable services. Inefficiencies of one-to-one matching of user requirements to a single service have given rise to service composition. Customized media delivery can be achieved through dynamic compositions of Service Specific Overlay Networks (SSONs). However, the presence of SSONs in dynamic environments raises the possibility of unexpected failures and quality degradations. Thus constructing, managing, and repairing corrupted service paths are challenging dilemmas. This thesis investigates the problem of autonomous SSON construction and management and identifies the drawbacks of current approaches. A novel multi-layered, autonomous, self-adaptive framework for constructing SSONs is presented. The framework includes a Hybrid Service Overlay Network layer (H-SON). The H-SON is a dynamic hybrid overlay dedicated to service composition for multimedia delivery in dynamic networks. Node placement in the overlay depends on the node’s stability, types and quality of provided services. Changes in stability and QoS of service nodes are reflected by dynamic re-organizations of the overlay. The H-SON permits fast and efficient searches for component services that meet client functional and quality expectations. Self-managed overlay nodes coordinate their behaviors to formulate a service composition path that meets the client’s requirements. Two approaches are presented in this work. The first illustrates how SSONs are established through dynamically adaptable MS-designed plans. The imprecise nature of nonfunctional service characteristics, such as QoS, is modeled using a fuzzy logic system. Moreover, semantic similarity evaluations enable us to include, in compositions, those services whose operations match, semantically, the requirements of the composition plan. Plan-based composition solutions restrict service discovery to defined abstract models. Our second composition approach introduces a semantic similarity and nearness SSON composition method. The objective is to free service nodes from the adherence to restrictive composition plans. The presented work illustrates a service composition solution that semantically advances service composition paths towards meeting users’ needs with each service hop while simultaneously guaranteeing user-acceptable QoS levels. Simulation results showcase the effectiveness of the presented work. Gathered results validate the success of our service composition methods while meeting user requirements.

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Abdyldaeva, Rahat. "Qos-aware Service Selection For Web Service Composition." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614369/index.pdf.

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Composition of web services is one of the flexible and easiest approaches for creating composite services that fulfill complex tasks. Together with providing convenience in creation of new software applications, service composition has various challenges. One of them is the satisfaction of user-defined Quality of Service (QoS) requirements while selecting services for a composition. Load balancing issue is another challenge as uncontrolled workload may lead to violation of service providers&rsquo QoS declarations. This thesis work proposes a QoS aware method for optimum service composition while taking into account load balancing. M/M/C queuing model is utilized for the individual services to determine sojourn time distribution for possible compositions. Percentile of the execution time, price and availability are considered as QoS parameters. Proposed algorithm selects the optimum composition according to QoS constraints and utility provided by the services. The performance of the method is evaluated by custom simulation software and is compared to two other methods, random selection and average execution timebased optimal service selection.

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Baklouti, Fadhlallah. "Service composition in opportunistic networks." Thesis, Lorient, 2019. http://www.theses.fr/2019LORIS523/document.

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Cette thèse s’inscrit dans le domaine de l’informatique ambiante et del’Internet des objets, et considère des réseaux qui peuvent se formerspontanément et qui sont composés d’équipements fixes ou mobiles. Ceséquipements peuvent communiquer à travers une infrastructure, ou de gré-à-gré en mode ad hoc. Des ruptures de connectivité peuvent apparaître dans le réseau d’unemanière fréquente et imprévisible. Ces ruptures de connectivité peuvents’avérer problématiques dès lors que ces équipements souhaitent accéder àdes ressources offertes par d’autres équipements.L’informatique opportuniste étend le principe des communicationsopportunistes en proposant d’exposer les ressources à travers des serviceset d’accéder à ces services par des techniques et des protocoles decommunication opportunistes qui mettent en œuvre le principe du “store,carry and forward”.Dans cette thèse, nous nous intéressons à la composition de services afin depouvoir combiner les services élémentaires offerts par les équipementsprésents dans le réseau et ainsi proposer aux utilisateurs des services deplus haut niveau et plus riches. La composition de services représente unetâche complexe dans l’informatique opportuniste du fait des ruptures deconnexion.Dans cette thèse, nous proposons une solution pour composer les servicesen utilisant deux stratégies, à savoir la chorégraphie et l’orchestration. Cettesolution repose en outre sur une fonction d’utilité qui permet de sélectionnerles fournisseurs de services. Nous proposons également une versionaméliorée exploitant un cache distribué de données et un mécanismeproactif de composition de services exploitant les profils d’intérêt desutilisateurs This thesis is related to the domain of Ubiquitous computing and Internet ofThings (IoT), and focuses on networks that can be formed spontaneously bymobile or fixed devices. These devices can be connected using aninfrastructure, or in a peer-to-peer mode using ad hoc communications.Connection disruptions may occur in the network frequently andunpredictably. These connection disruptions can be problematic when a givendevice tries to access remote resources provided by other devices, or when ittries to offer its own resources to these ones.Opportunistic computing extends the paradigm of opportunistic networkingby abstracting local resources as services accessible remotely using theprotocols of opportunistic networking that implement the "store, carry andforward" principle.In this thesis, we focus on service composition in order to combineelementary services and offer new, rich and high level composite services tousers. Service composition can be a very difficult task to perform inopportunistic networks due to connection disruptions. In this thesis, we propose a solution to compose services using twostrategies: orchestration and choreography. This solution also relies on autility function that selects service providers. We also propose an optimizedversion of our solution that exploits a distributed cache of data and aproactive service composition mechanism based on the user interest profile

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Ai, Lifeng. "QoS-aware web service composition using genetic algorithms." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/46666/1/Lifeng_Ai_Thesis.pdf.

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Web service technology is increasingly being used to build various e-Applications, in domains such as e-Business and e-Science. Characteristic benefits of web service technology are its inter-operability, decoupling and just-in-time integration. Using web service technology, an e-Application can be implemented by web service composition — by composing existing individual web services in accordance with the business process of the application. This means the application is provided to customers in the form of a value-added composite web service. An important and challenging issue of web service composition, is how to meet Quality-of-Service (QoS) requirements. This includes customer focused elements such as response time, price, throughput and reliability as well as how to best provide QoS results for the composites. This in turn best fulfils customers’ expectations and achieves their satisfaction. Fulfilling these QoS requirements or addressing the QoS-aware web service composition problem is the focus of this project. From a computational point of view, QoS-aware web service composition can be transformed into diverse optimisation problems. These problems are characterised as complex, large-scale, highly constrained and multi-objective problems. We therefore use genetic algorithms (GAs) to address QoS-based service composition problems. More precisely, this study addresses three important subproblems of QoS-aware web service composition; QoS-based web service selection for a composite web service accommodating constraints on inter-service dependence and conflict, QoS-based resource allocation and scheduling for multiple composite services on hybrid clouds, and performance-driven composite service partitioning for decentralised execution. Based on operations research theory, we model the three problems as a constrained optimisation problem, a resource allocation and scheduling problem, and a graph partitioning problem, respectively. Then, we present novel GAs to address these problems. We also conduct experiments to evaluate the performance of the new GAs. Finally, verification experiments are performed to show the correctness of the GAs. The major outcomes from the first problem are three novel GAs: a penaltybased GA, a min-conflict hill-climbing repairing GA, and a hybrid GA. These GAs adopt different constraint handling strategies to handle constraints on interservice dependence and conflict. This is an important factor that has been largely ignored by existing algorithms that might lead to the generation of infeasible composite services. Experimental results demonstrate the effectiveness of our GAs for handling the QoS-based web service selection problem with constraints on inter-service dependence and conflict, as well as their better scalability than the existing integer programming-based method for large scale web service selection problems. The major outcomes from the second problem has resulted in two GAs; a random-key GA and a cooperative coevolutionary GA (CCGA). Experiments demonstrate the good scalability of the two algorithms. In particular, the CCGA scales well as the number of composite services involved in a problem increases, while no other algorithms demonstrate this ability. The findings from the third problem result in a novel GA for composite service partitioning for decentralised execution. Compared with existing heuristic algorithms, the new GA is more suitable for a large-scale composite web service program partitioning problems. In addition, the GA outperforms existing heuristic algorithms, generating a better deployment topology for a composite web service for decentralised execution. These effective and scalable GAs can be integrated into QoS-based management tools to facilitate the delivery of feasible, reliable and high quality composite web services.

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Milanovic, Nikola. "Contract based web service composition." Doctoral thesis, [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980381371.

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MEDEIROS, Robson Wagner Albuquerque de. "Cost management of service composition." Universidade Federal de Pernambuco, 2017. https://repositorio.ufpe.br/handle/123456789/24891.

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Submitted by Pedro Barros (pedro.silvabarros@ufpe.br) on 2018-06-25T21:17:28Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Robson Wagner Albuquerque de Medeiros.pdf: 7700135 bytes, checksum: 95fd086484ed6a7d7c683141fa9f4f13 (MD5) Made available in DSpace on 2018-06-25T21:17:28Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Robson Wagner Albuquerque de Medeiros.pdf: 7700135 bytes, checksum: 95fd086484ed6a7d7c683141fa9f4f13 (MD5) Previous issue date: 2017-03-07 Service-Oriented Architecture (SOA) is a software design style based on the notion of Service-Oriented Computing (SOC) that facilitates the interoperability among computer systems of possibly different businesses. Cost is one of the most challenging factors inﬂuencing SOA adoption in organisations and a signiﬁcant factor in SOA project success. Nevertheless, many institutions across the world have adopted SOA to interconnect their computing infrastructures (Business-to-Business) and offer interfaces to their customers (Business-to-Customer). For these companies, SOA can address their needs to access the market more quickly, respond to changes in a business environment, improve business processes, improve customers’ services and even reduce costs. In SOA, service composition has emerged as an important strategy to enable collaboration of applications provided by different companies (Business-to-Business). With the increasing number of Web services having similar functionality but different pricing schemes, choosing the most appropriate set of services with the lowest cost has been a challenge in service compositions. Several techniques to compute and analyse the cost of service compositions already exist. However, there is still no approach to developing cost management systems able to assist in the planning, deﬁnition, scheduling, execution, monitoring and adaptation of compositions taking into account all classes of cost behaviour and all type of cost drivers. Thus, the principal objective of this thesis is to present a framework to manage cost throughout the service composition life-cycle in an integrated way taking into account cost properties of services and service compositions. Therefore, we provide a metamodel to specify complex cost behaviours. Also, we propose algorithms to compute service costs and select the best services that meet the cost requirements of the service composition according to the cost behaviour of each service. Moreover, we propose an architecture for developing engines able to manage the cost throughout the service composition life-cycle. Finally, we implemented a prototype based on the proposed architecture and executed experiments that show the effectiveness and efﬁciency of our approach to managing the cost of service composition. A Arquitetura Orientada a Serviços (do inglêsSOA) é um estilo de projeto de software baseado na Computação Orientada a Serviço (do inglêsSOC) que facilita a interoperabilidade entre os sistemas de computadores de empresas possivelmente diferentes. Custo é um dos fatores mais desaﬁadores que inﬂuenciam a adoção de SOA nas organizações e um fator signiﬁcativo no sucesso do projeto SOA. No entanto, muitas organizações em todo o mundo adotaram SOA para interconectar suas infra-estruturas de computação (Business-to-Business) e oferecer interfaces para seus clientes (Business-to-Customer). Para essas empresas, SOA pode atender às suas necessidades de acesso ao mercado mais rapidamente, responder às mudanças em um ambiente de negócio, melhorar os processos de negócios, melhorar os serviços dos clientes e até mesmo reduzir os custos. Em SOA, a composição de serviço emergiu como uma estratégia importante para permitir a colaboração de aplicações fornecidas por diferentes empresas (Business-toBusiness). Com o crescente número de serviços Web com funcionalidades semelhantes, mas com modelos de preciﬁcação diferentes, a escolha do conjunto de serviços com o menor custo tem sido um desaﬁo nas composições de serviços. Na literatura existem técnicas para calcular e analisar o custo de composições de serviços. No entanto, ainda não há uma abordagem para desenvolver sistemas de gerenciamento de custos capazes de auxiliar no planejamento, deﬁnição, escalonamento, execução, monitoramento e adaptação de composições levando em conta todas as classes de comportamento de custo e os diferentes tipo de fatores de custo adotados pelos provedores de serviços. O objetivo principal desta tese é apresentar um framework para gerenciar composições de serviços ao longo de todas as fases do seu ciclo de vida de uma forma integrada levando em consideração comportamentos complexos de custo de serviços. Sendo assim, fornecemos um metamodelo para especiﬁcar comportamentos complexos de custo. Além disso, propomos algoritmos para calcular os custos e selecionar os melhores serviços que atendam aos requisitos de custo da composição de acordo com o modelo de comportamento de custo de cada serviço. Além disso, propomos uma arquitetura para o desenvolvimento de engines de execução capazes de gerenciar o custo ao longo do ciclo de vida da composição. Finalmente, desenvolvemos um protótipo baseado na arquitetura proposta e executamos experimentos que mostram a eﬁcácia e a eﬁciência de nossa abordagem para gerenciar custo de composições de serviço.

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Lopes, Pedro Jorge Pereira. "Service composition for biomedical applications." Doctoral thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/10545.

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Doutoramento em Engenharia Informática A exigente inovação na área das aplicações biomédicas tem guiado a evolução das tecnologias de informação nas últimas décadas. Os desafios associados a uma gestão, integração, análise e interpretação eficientes dos dados provenientes das mais modernas tecnologias de hardware e software requerem um esforço concertado. Desde hardware para sequenciação de genes a registos electrónicos de paciente, passando por pesquisa de fármacos, a possibilidade de explorar com precisão os dados destes ambientes é vital para a compreensão da saúde humana. Esta tese engloba a discussão e o desenvolvimento de melhores estratégias informáticas para ultrapassar estes desafios, principalmente no contexto da composição de serviços, incluindo técnicas flexíveis de integração de dados, como warehousing ou federação, e técnicas avançadas de interoperabilidade, como serviços web ou LinkedData. A composição de serviços é apresentada como um ideal genérico, direcionado para a integração de dados e para a interoperabilidade de software. Relativamente a esta última, esta investigação debruçou-se sobre o campo da farmacovigilância, no contexto do projeto Europeu EU-ADR. As contribuições para este projeto, um novo standard de interoperabilidade e um motor de execução de workflows, sustentam a sucesso da EU-ADR Web Platform, uma plataforma para realizar estudos avançados de farmacovigilância. No contexto do projeto Europeu GEN2PHEN, esta investigação visou ultrapassar os desafios associados à integração de dados distribuídos e heterogéneos no campo do varíoma humano. Foi criada uma nova solução, WAVe - Web Analyses of the Variome, que fornece uma coleção rica de dados de variação genética através de uma interface Web inovadora e de uma API avançada. O desenvolvimento destas estratégias evidenciou duas oportunidades claras na área de software biomédico: melhorar o processo de implementação de software através do recurso a técnicas de desenvolvimento rápidas e aperfeiçoar a qualidade e disponibilidade dos dados através da adopção do paradigma de web semântica. A plataforma COEUS atravessa as fronteiras de integração e interoperabilidade, fornecendo metodologias para a aquisição e tradução flexíveis de dados, bem como uma camada de serviços interoperáveis para explorar semanticamente os dados agregados. Combinando as técnicas de desenvolvimento rápidas com a riqueza da perspectiva "Semantic Web in a box", a plataforma COEUS é uma aproximação pioneira, permitindo o desenvolvimento da próxima geração de aplicações biomédicas. The demand for innovation in the biomedical software domain has been an information technologies evolution driver over the last decades. The challenges associated with the effective management, integration, analyses and interpretation of the wealth of life sciences information stemming from modern hardware and software technologies require concerted efforts. From gene sequencing hardware to pharmacology research up to patient electronic health records, the ability to accurately explore data from these environments is vital to further improve our understanding of human health. This thesis encloses the discussion on building better informatics strategies to address these challenges, primarily in the context of service composition, including warehousing and federation strategies for resource integration, as well as web services or LinkedData for software interoperability. Service composition is introduced as a general principle, geared towards data integration and software interoperability. Concerning the latter, this research covers the service composition requirements within the pharmacovigilance field, namely on the European EU-ADR project. The contributions to this area, the definition of a new interoperability standard and the creation of a new workflow-wrapping engine, are behind the successful construction of the EUADR Web Platform, a workspace for delivering advanced pharmacovigilance studies. In the context of the European GEN2PHEN project, this research tackles the challenges associated with the integration of heterogeneous and distributed data in the human variome field. For this matter, a new lightweight solution was created: WAVe, Web Analysis of the Variome, provides a rich collection of genetic variation data through an innovative portal and an advanced API. The development of the strategies underlying these products highlighted clear opportunities in the biomedical software field: enhancing the software implementation process with rapid application development approaches and improving the quality and availability of data with the adoption of the Semantic Web paradigm. COEUS crosses the boundaries of integration and interoperability as it provides a framework for the flexible acquisition and translation of data into a semantic knowledge base, as well as a comprehensive set of interoperability services, from REST to LinkedData, to fully exploit gathered data semantically. By combining the lightness of rapid application development strategies with the richness of its "Semantic Web in a box" approach, COEUS is a pioneering framework to enhance the development of the next generation of biomedical applications.

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Ye, Chunyang. "Atomicity analysis for service composition /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?CSED%202008%20YE.

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Jäger, Michael C. "Optimising quality of service for the composition of electronic services." [S.l.] : [s.n.], 2006. http://opus.kobv.de/tuberlin/volltexte/2007/1472.

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Kuzu, Mehmet. "Automatic Web Service Composition With Ai Planning." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610756/index.pdf.

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In this thesis, some novel ideas are presented for solving automated web service composition problem. Some possible real world problems such as partial observability of environment, nondeterministic effects of web services, service execution failures are solved through some mechanisms. In addition to automated web service composition, automated web service invocation task is handled in this thesis by using reflection mechanism. The proposed approach is based on AI planning. Web service composition problem is translated to AI planning problem and a novel AI planner namely &ldquo Simplanner&rdquo that is designed for working in highly dynamic environments under time constraints is adapted to the proposed system. World altering service calls are done by conforming to the WS-Coordination and WS-Business Activity web service transaction specifications in order to physically repair failure situations and prevent undesired side effects of aborted web service composition efforts.

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Meit, Michael, Kate E. Beatty, and Megan Heffernan. "Exploring Service Composition and Financing Among Rural LHDs." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etsu-works/6836.

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Barakat, Lina. "Efficient adaptive multi-granularity service composition." Thesis, King's College London (University of London), 2013. https://kclpure.kcl.ac.uk/portal/en/theses/efficient-adaptive-multigranularity-service-composition(989b88fd-3a7b-4446-9322-09323032fe99).html.

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Despite the tremendous benefits of the dynamic, service-oriented approach to build composite applications, it also brings great challenges. In particular, the run-time selection of the most suitable services for an application in a timely manner is not trivial, since many providers could be competing for the same type of service, but at different quality of service levels. Due to possible dependencies among services, such quality offerings could also vary at a single service level. This is further complicated by the fact that the available services may offer to achieve the tasks required at varying functional abstractions. Moreover, services are highly dynamic and unreliable in nature, which can cause serious problems to the execution of workflows relying on such services. In this thesis, we contribute towards addressing these challenges, and achieve a more efficient, robust, and optimal dynamic composition process. Specifically, through a rich collection of alternative planning options, we allow services at various granularity levels to be incorporated into the selection process. We also enrich the quality model of services with inter-service dependency awareness, to produce correct quality estimations. Furthermore, we develop efficiency-boosting techniques facilitating a scalable service selection process without affecting optimality, even in the case where the search space experiences complex dependencies among services. In the face of environment dynamism and uncertainty, we achieve an early and efficient adaptive behaviour, which ensures a valid, optimal, and satisfactory solution, in spite of high environment volatility, and without causing disruption to application execution. The effectiveness of all the algorithms and techniques developed in this thesis is demonstrated analytically and empirically. The latter is achieved both on randomly generated datasets, and through a case study evaluation applied in the context of learning object composition.

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Du, Xiaofeng. "Semantic service description framework for efficient service discovery and composition." Thesis, Durham University, 2009. http://etheses.dur.ac.uk/111/.

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Web services have been widely adopted as a new distributed system technology by industries in the areas of, enterprise application integration, business process management, and virtual organisation. However, lack of semantics in current Web services standards has been a major barrier in the further improvement of service discovery and composition. For the last decade, Semantic Web Services have become an important research topic to enrich the semantics of Web services. The key objective of Semantic Web Services is to achieve automatic/semi-automatic Web service discovery, invocation, and composition. There are several existing semantic Web service description frameworks, such as, OWL-S, WSDL-S, and WSMF. However, existing frameworks have several issues, such as insufficient service usage context information, precisely specified requirements needed to locate services, lacking information about inter-service relationships, and insufficient/incomplete information handling, make the process of service discovery and composition not as efficient as it should be. To address these problems, a context-based semantic service description framework is proposed in this thesis. This framework focuses on not only capabilities of Web services, but also the usage context information of Web services, which we consider as an important factor in efficient service discovery and composition. Based on this framework, an enhanced service discovery mechanism is proposed. It gives service users more flexibility to search for services in more natural ways rather than only by technical specifications of required services. The service discovery mechanism also demonstrates how the features provided by the framework can facilitate the service discovery and composition processes. Together with the framework, a transformation method is provided to transform exiting service descriptions into the new framework based descriptions. The framework is evaluated through a scenario based analysis in comparison with OWL-S and a prototype based performance evaluation in terms of query response time, the precision and recall ratio, and system scalability.

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Papadopoulos, Petros. "Self-organising service composition in open service-oriented architecture systems." Thesis, Glasgow Caledonian University, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.688278.

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Dantas, Ramide Augusto Sales. "Quality-aware Automated Service Composition using Reverse Engineering and Incomplete Information." Universidade Federal de Pernambuco, 2012. https://repositorio.ufpe.br/handle/123456789/10952.

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Submitted by Pedro Henrique Rodrigues (pedro.henriquer@ufpe.br) on 2015-03-05T19:29:15Z No. of bitstreams: 2 phd-thesis-vfinal-rasd.pdf: 2993974 bytes, checksum: a924d1ac8059a7b4a6c2775d60d5a742 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Made available in DSpace on 2015-03-05T19:29:15Z (GMT). No. of bitstreams: 2 phd-thesis-vfinal-rasd.pdf: 2993974 bytes, checksum: a924d1ac8059a7b4a6c2775d60d5a742 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2012-03-13 Service Composition is one of the most important features offered by Service Oriented Computing. The composition allows a new service to be created through the reuse of existing ones. The process of creating a composition involves discovering the necessary services and combining them in an appropriate manner using specific languages and tools. This process, however, is still carried out mainly by hand. Considering the dynamic nature of distributed services, manual composition may become too complex, affecting the productivity gains provided by reuse. Proposals to fully or partially automate this process already exist, most of them based on Automated Planning algorithms borrowed from Artificial Intelligence. Although functional, these approaches have practical problems that hinder their effective implementation in production scenarios. In this Thesis, we addressed some of the practical problems of automated composition, starting with the need for formal descriptions of services. These formal descriptions are necessary for the composition algorithms, however, are rarely available from services. This issue was addressed by means of reverse engineering a repository of service compositions. By analyzing how the services were related to each other in the compositions, it was possible to obtain the necessary information for the algorithms to work. We also evaluated the quality of the compositions generated by the algorithms and their similarity with respect to compositions created manually. Automated Planning algorithms from the literature have been modified in order to generate solutions closer to those expected by the developer. Finally, the composition algorithms were adapted to accept incomplete specifications, thus allowing the developer to obtain a solution even not knowing a priori all the composition details. Comparisons with automated planning tools were conducted in order to ascertain the effectiveness of the algorithms. The results show that the automated composition, as presented in the Thesis, can be an invaluable tool to the service developer.

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COMERIO, MARCO. "Web service contracts: specification, selection and composition." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2010. http://hdl.handle.net/10281/7779.

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Web services promise universal interoperability and integration of services developed by independent providers to execute business processes by discovering and composing services distributed over the Internet. This means that a key factor to build complex and valuable processes among cooperating organizations relies on the efficiency of discovering appropriate Web services and composing them. The increasing availability of Web services that offer similar functionalities requires mechanisms to go beyond the pure functional discovery and composition of Web services. A promising solution towards the automatic enactment of valuable processes consists in enhancing Web service discovery and composition with the evaluation of semantic contracts that define non-functional properties (NFPs) and applicability conditions associated with a Web service. Nevertheless, currently there is a lack of tools and algorithms that fully support this solution due to several open issues. First, existing languages do not show the expressivity necessary for Web service contract specifications. Second, there is a lack of standard languages that determines heterogeneity in Web service contract specifications raising interoperability issues. Third, pure semantic approaches to enhance Web service discovery allows for detailed descriptions but present performance problems due to current limitations of semantic tools when dealing with reasoning tasks. Fourth, Web service contract compatibility evaluation is not supported by existing composition tools when combining different services from different providers. This dissertation addresses these open issues and proposes solutions in terms of models, algorithms and tools.

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Li, Wenbin. "Towards a resilient service oriented computing based on ad-hoc web service compositions in dynamic environments." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0032/document.

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Le processus de composition des services Web joue un rôle important dans la réalisation des architectures orientées services (SOA). Dans les environnements dynamiques dans lesquels des informations con-textuelles changent souvent, le processus de composition est souvent affec-té pendant les phases de conception et d’exécution. Ce processus devrait par conséquence être en mesure de s'adapter aux changements en temps de conception et exécution. A présent, les architectures orientées services et les mécanismes automatiques de composition de services Web ne parviennent pas à faire face aux changements continus et imprévisibles. Construire des architectures orientées services qui s'adaptent aux changements dans des environnements dynamiques révèle un défi pour les processus de com-position de services Web. En outre, les processus de composition actuelles offrent un support limité pour les utilisateurs professionnels de spécifier leurs exigences métier afin générer automatiquement les processus métiers (services Web composites). Par cela, l'écart entre les exigences fonction-nelles et non-fonctionnelles au niveau métier et les exigences techniques liées aux mécanismes de composition de services Web augmentent la com-plexité du développement d'applications ou de processus métier adaptés aux environnements dynamiques. Pour remédier à ces défis, nous introduisons le concept de rési-lience appliqué à l'informatique orientée services (nommé SOC résilient) afin de construire des applications et processus métier dynamiques en res-pectant les exigences métier dans des environnements dynamiques. La SOA résilient est conçue comme un ensemble de modèles qui affectent, et sont affectées par, d’autres modèles. Dans cette thèse, nos contributions, qui se concentrent en particulier sur le modèle d’exigence de composition et le modèle de composition des services Web, composent trois parties princi-pales: tout d'abord le modèle de d’exigence est modélisé aux trois niveaux, i.e., métier, capacité, et règle. Particulièrement, le modèle de d’exigence métier offre aux utilisateurs un langage structuré à base de langage naturelle pour spécifier les processus métier; d'autre part, un processus de trans-formation dérive par transformation un modèle d’exigence de composition à base de règles. Chaque règle représente un ensemble de contraintes multi-objectives concernant différentes variables liées au processus de composi-tion et à son environnement dynamique. Troisièmement, une approche ad-hoc de composition des services Web a été développée pour construire de services composites sans plans de composition prédéfinis dans des environ-nements dynamiques. L’approche de transformation de modèle-à-modèle génère les règles qui sont récursivement utilisées pour modifier ces modèles et ensuite replanifiés une composition ad-hoc de services Web Due to the distributed and asynchronous nature of Web services, the Web service composition process plays an important role in achieving SOC. In dynamic environments by which contextual information such as Web service properties and composition requirements often change, the composition process is thus affected and, consequently, should be able to adapt composite applications to changes at design time and runtime. Un-fortunately, current Service-Oriented Architecture (SOA) and Web service composition approaches lack of the ability to deal with continuous and un-predictable changes. Building resilient service-oriented architectures that are adaptable to endogenous and exogenous changes in dynamic environments reveal a drastic challenge to current composition processes. In addition, current composition processes provide a limited support for business users to specify their requirements in business languages to automatically compose business processes (i.e., composite services). By such, the gap be-tween business requirements and composition requirements related to Web services increases the complexity of developing adaptable SOA-based ap-plications and processes in dynamic environments. To overcome these challenges, we introduce the concept of Resili-ent Service-Oriented Computing (rSOC) to construct resilient SOA-based applications driven by business requirements in dynamic environments. To this end, the resilient SOA is defined as a set of models that affect and are affected by each other, and relies on a model-to-model transformation ap-proach to ensure SOA adaptability and evolution. In this thesis, we particu-larly focus on two models: a three-level composition requirement model and a Web service composition model, to establish the foundation for a re-silient SOA as follows: firstly, composition requirements are modeled in three levels, i.e., business-centric, capability-focused and rule-driven. Par-ticularly the business-centric requirement model provides business users with a structured natural language to specify requirements; secondly, a two-phase requirement transformation process builds the rule-driven Web ser-vice composition requirement model from the business-centric requirement model as set of composition rules, expressing multi-objective constraints that affect the composition process and its dynamic environment; thirdly, an ad-hoc Web service composition approach is introduced to flexibly con-struct composite services without predefined composition plans. Particularly, composition rules generated in composition process may affect other model(s) in the resilient SOA, such as composition requirement model, and recursively invoke the model-to-model transformation approach to replan the ad-hoc Web service composition approach

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Ben, hadj yahia Elyas. "A Language-Based Approach for Web Service Composition." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0783/document.

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Au vu des dernières avancées dans le domaine de l’ingénierie web, ainsi qu’avec la baisse de coût du cloud computing, les architectures orientées services sont rapidement devenues la solution prépondérante pour fournir des services à valeur ajoutée aux clients. Suite à cette tendance, la composition de services tiers est devenue un paradigme de référence pour le développement d’applications robustes et riches, ou encore pour l’automatisation de processus métiers. Avec la disponibilité de centaines de milliers de services et APIs web, la réalisation de telles intégrations devient lourde et fastidieuse quand effectuée manuellement. Par ailleurs, chaque client peut exiger des besoins et politiques d’intégration différentes, ce qui complexifie davantage la tâche. De plus, fournir une telle solution qui soit à la fois robuste et scalable est une tâche non-triviale. Il est donc primordial d’étudier comment coordonner de manière efficace les interactions entre les services web existants. Ainsi, cette thèse vise à étudier les problématiques liées à la composition de services web dans le contexte des pratiques de développement web modernes. Nous présentons un cadre architectural permettant la spécification de compositions de services web grâce à une approche orientée langage, et montrons comment supporter leur exécution de manière scalable grâce à MEDLEY, une plateforme légère et orientée événements In light of the recent advances in the field of web engineering, along with the decrease of cost of cloud computing, service-oriented architectures rapidly became the leading solution in providing valuable services to clients. Following this trend, the composition of third-party services has become a successful paradigm for the development of robust and rich distributed applications, as well as automating business processes. With the availability of hundreds of thousands of web services and APIs, such integrations become cumbersome and tedious when performed manually. Furthermore, different clients may require different integration requirements and policies, which further complexifies the task. Moreover, providing such a solution that is both robust and scalable is a non-trivial task. Therefore, it becomes crucial to investigate how to efficiently coordinate the interactions between existing web services. As such, this thesis aims at investigating the underlying challenges in web service composition in the context of modern web development practices. We present an architectural framework to support the specification of web service compositions using a language-based approach, and show how we support their execution in a scalable manner using MEDLEY, a lightweight, event-driven platform

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Kaya, Ertay. "Providing Scalability For An Automated Web Service Composition Framework." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612033/index.pdf.

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In this thesis, some enhancements to an existing automatic web service composition and execution system are described which provide a practical significance to the existing framework with scalability, i.e. the ability to operate on large service sets in reasonable time. In addition, the service storage mechanism utilized in the enhanced system presents an effective method to maintain large service sets. The described enhanced system provides scalability by implementing a pre-processing phase that extracts service chains and problem initial and goal state dependencies from service descriptions. The service storage mechanism is used to store this extracted information and descriptions of available services. The extracted information is used in a forward chaining algorithm which selects the potentially useful services for a given composition problem and eliminates the irrelevant ones according to the given problem initial and goal states. Only the selected services are used during the AI planning and execution phases which generate the composition and execute the services respectively.

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Karakoc, Erman. "Web Service Composition Under Resource Allocation Constraints." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608309/index.pdf.

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Web service composition is an inevitable aspect of web services technology, which solves complex problems by combining available basic services and ordering them to best suit the problem requirements. Automatic composition gives us flexibility of selecting best candidate services at composition time, this would require the user to define the resource allocation constraints for selecting and composing candidate web services. Resource allocation constraints define restrictions on how to allocate resources, and scheduling under resource allocation constraints to provide proper resource allocation to tasks. In this work, web service composition system named as CWSF (Composite Web Service Framework) constructed for users to define a workflow system in which a rich set of constraints can be defined on web services. On the contrary many technologies and studies, CWSF provides a user-friendly environment for modeling web service composition system. The output of the framework is the scheduling of web service composition in which how and when web services are executed are defined. With this work, a language, CWSL is defined to describe workflow, resource allocation constraints, selection and discovery rules of web services and associated semantic information. An important property of CWSF system is converting web service composition problem into a constraint satisfaction problem to find the best solution that meet the all criteria defined by user. Furthermore, CWSF has ability to display other possible solutions to provides users flexibility. This study also includes semantic matching and mapping facilities for service discovery.

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Hamadi, Rachid Computer Science &amp Engineering Faculty of Engineering UNSW. "Formal Composition and Recovery Policies in Service-Based Business Processes." Awarded by:University of New South Wales. Computer Science and Engineering, 2005. http://handle.unsw.edu.au/1959.4/20666.

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Process-based composition of Web services is emerging as a promising technology for the effective automation of integrated and collaborative applications. As Web services are often autonomous and heterogeneous entities, coordinating their interactions to build complex processes is a difficult, error prone, and time-consuming task. In addition, since Web services usually operate in dynamic and highly evolving environments, there is a need for supporting flexible and correct execution of integrated processes. In this thesis, we propose a Petri net-based framework for formal composition and recovery policies in service-based business processes. We first propose an algebra for composing Web services. The formal semantics of this algebra is expressed in terms of Petri nets. The use of a formal model allows the effective verification and analysis of properties, both within a service, such as termination and absence of deadlock, and between services, such as behavioral equivalences. We also develop a top down approach for the correct (e.g., absence of deadlock and termination) composition of complex business processes. The approach defines a set of refinement operators that guarantee correctness of the resulting business process nets at design time. We then introduce Self-Adaptive Recovery Net (SARN), an extended Petri net model for specifying exceptional behavior in business processes. SARN adapts the structure of the underlying Petri net at run time to handle exceptions while keeping the Petri net design simple and easy. The proposed framework caters for the specification of high-level recovery policies that are incorporated either with a single task or a set of tasks, called a recovery region. Finally, we propose a pattern-based approach to dynamically restructure SARN. These patterns capture the ways past exceptions have been dealt with. The objective is to continuously restructure recovery regions within the SARN model to minimize the impact of exception handling. To illustrate the viability of the proposed composition and exception handling techniques, we have developed HiWorD (HIerarchical WORkflow Designer), a hierarchical Petri net-based business process modeling and simulation tool.

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Abid, Ahmed. "Improvement of web service composition using semantic similarities and formal concept analysis." Thesis, Tours, 2017. http://www.theses.fr/2017TOUR4007.

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Les Architectures Orientées Services (SOA) se sont progressivement imposées comme outil incontournable dans les échanges inter-entreprises grâce à leurs potentiels stratégiques et technologiques. Leurs mise en oeuvre est concrétisée à travers les services Web dont l'un des principaux atouts est leur composabilité. Avec l'émergence du Web sémantique la découverte et la composition de services Web sémantiques constituent un réel défi. Le processus de découverte s'appui généralement sur les registres traditionnels offrant des descriptions syntaxiques regroupés statiquement, ce qui pose un problème lié à l'hétérogénéité des descriptions syntaxiques et à la rigidité de la classification. Le processus de composition dépend à son tour de la qualité de l'appariement des services. Nous proposons dans cette thèse une architecture d'un framework qui couvre toutes les phases du processus de composition. Ensuite, nous proposons une mesure de similarité sémantique pour un appariement entre les descriptions des services Web. Le processus de découverte de services Web s'appuie sur la similarité entre les services, le formalisme d'Analyse de Concepts Formels et l'organisation des services en treillis. La composition ensuite repose sur l'établissement de services composites cohérents et pertinaents pour la fonctionnalité espérée. Les points forts de cette architecture sont l'adaptation et l'intégration des technologies sémantiques, le calcul de similarité sémantique et l'utilisation de cette similarité sémantique et du formalisme FCA afin d'optimiser le processus de composition Service Oriented Architectures (SOA) have been progressively confirmed as an essential tool in inter-companies exchanges thanks to their strategic and technological potential. Their implementation is realised through Web services. One of the main assets of services is their compostability. With the emergence of the semantic Web, the discovery and composition of semantic Web services become a real challenge. The discovery process is generally based on traditional registries with syntactic descriptions where services are statically grouped. This poses a problem related to the heterogeneity of syntactic descriptions and the rigidity of the classification. The composition process depends on the Web service matching quality processed in the discovery phase. We propose in this dissertation an architecture of a framework that covers all the phases of the composition process. Then, we propose a semantic similarity measure Web services. The Web services discovery process relies on the proposed similarity measure, the formal concept analysis (FCA) formalism, and the organisation of lattice services. The composition is then based on the establishment of coherent and relevant composite services for the expected functionality. The main strengths of this architecture are the adaptation and integration of semantic technologies, the calculation of semantic similarity and the use of this semantic similarity and the FCA formalism in order to optimise the composition process

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Aydin, Onur. "Automated Web Service Composition With Event Calculus." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606549/index.pdf.

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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.

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Kulstad, Rune Bleken. "End-User service composition framework and application." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for telematikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18498.

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In todays public market Mobile phones has become a part of everyday life. The introduc-tion of Smart Phones has created a new market for services and applications for the Smart Phones. Many of these users would benefit of customizing their own services to fulfil their needs. This can be achieved with end-user service composition. End-user service composition enables the user to compose their own services from already existing components to provide val-ue added services. In this Master Thesis a service composition tool consisting of the two applica-tions Easy Composer and EasyDroid is presented. The idea of the tool is that ordinary people without technical background will be able to quickly compose their own services in a simple manner. The existing tool has been in development for a while, but still lack some sufficient quality in terms of usability and utility for ordinary people to make use of it. Utility means what the tool can be utilized to, and usability means the user-friendliness and usefulness. In this Mas-ter Thesis a new system has been made for the service composition tool. The Easy Composer application has been discarded and new web based GUI has replaced its functionality. In addi-tion, the EasyDroid application has been remade and a new server side has been developed. Fur-thermore, the communication between the different parts has been improved. The usability and utility of the previous system has been considerably improved in the new system. In other words the existing functionality has been made more user friendly and new functionality has been added to the tool. The goal is that the service composition tool would have the sufficient quality and novelty for ordinary users to embrace it.

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De, Leusse Pierre. "Contextual governance for service oriented architecture composition." Thesis, University of Newcastle Upon Tyne, 2011. http://hdl.handle.net/10443/2109.

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Currently, business requirements for rapid operational efficiency, customer responsiveness as well as rapid adaptability are driving the need for ever increasing communication and integration capabilities ofthe software assets. Functional decomposition into re-usable software entities, loose coupling, and distribution of resources are all perceived benefits of the investment on Service Oriented Architecture (SOA). This malleability can also bring about the risk of a more difficult oversight. The same service is ideally used in different applications and contexts. This situation forces a supporting infrastructure to allow and manage the adaptability to these different contexts of use. In this thesis, the author proposes to govern such variations in a cost efficient way by composing the core business function offered by a service with other services implementing infrastructure capabilities that fulfil varying non-functional requirements. However, as the number of services increases and their use in different contexts proliferates, it becomes necessary to automate policy enforcement and compliance monitoring. Furthermore, the composition of services into different business applications over a common infrastructure intensifies the need for end-to-end monitoring and analysis in order to assess the business performance impact. Managing the full life-cycle of service definition, deployment, exposure and operation requires management processes that take into account their composition with the infrastructure capabilities that take of non-functional requirements. In addition, policies may change during the life-time of a service. Policy updates may be the result of various reasons including business optimisation, of reaction to new business opportunities, of risk / threat mitigation, of operational emergencies, etc. It becomes therefore clear that a well-designed governance architecture is a prerequisite to implementing a SOA capable of dealing with a complex and dynamic environment.

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Hajji, Wajdi. "Dynamic service chain composition in virtualised environment." Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/36076.

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Network Function Virtualisation (NFV) has contributed to improving the flexibility of network service provisioning and reducing the time to market of new services. NFV leverages the virtualisation technology to decouple the software implementation of network appliances from the physical devices on which they run. However, with the emergence of this paradigm, providing data centre applications with an adequate network performance becomes challenging. For instance, virtualised environments cause network congestion, decrease the throughput and hurt the end user experience. Moreover, applications usually communicate through multiple sequences of virtual network functions (VNFs), aka service chains, for policy enforcement and performance and security enhancement, which increases the management complexity at to the network level. To address this problematic situation, existing studies have proposed high-level approaches of VNFs chaining and placement that improve service chain performance. They consider the VNFs as homogenous entities regardless of their specific characteristics. They have overlooked their distinct behaviour toward the traffic load and how their underpinning implementation can intervene in defining resource usage. Our research aims at filling this gap by finding out particular patterns on production and widely used VNFs. And proposing a categorisation that helps in reducing network latency at the chains. Based on experimental evaluation, we have classified firewalls, NAT, IDS/IPS, Flow monitors into I/O- and CPU-bound functions. The former category is mainly sensitive to the throughput, in packets per second, while the performance of the latter is primarily affected by the network bandwidth, in bits per second. By doing so, we correlate the VNF category with the traversing traffic characteristics and this will dictate how the service chains would be composed. We propose a heuristic called Natif, for a VNF-Aware VNF insTantIation and traFfic distribution scheme, to reconcile the discrepancy in VNF requirements based on the category they belong to and to eventually reduce network latency. We have deployed Natif in an OpenStack-based environment and have compared it to a network-aware VNF composition approach. Our results show a decrease in latency by around 188% on average without sacrificing the throughput.

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De, Gyvés Avila Silvana. "QoS awareness and adaptation in service composition." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/7886/.

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The dynamic nature of a Web service execution environment generates frequent variations in the Quality of Service offered to the consumers, therefore, obtaining the expected results while running a composite service is not guaranteed. When combining this highly changing environment with the increasing emphasis on Quality of Service, management of composite services turns into a time consuming and complicated task. Different approaches and tools have been proposed to mitigate the impacts of unexpected events during the execution of composite services. Among them, self-adaptive proposals have stood out, since they aim to maintain functional and quality levels, by dynamically adapting composite services to the environment conditions, reducing human intervention. The research presented in this Thesis is centred on self-adaptive properties in service composition, mainly focused on self-optimization. Three models have been proposed to target self-optimization, considering various QoS parameters, the benefit of performing adaptation, and looking at adaptation from two perspectives: reactive and proactive. They target situations where the QoS of the composition is decreasing. Also, they consider situations where a number of the accumulated QoS values, in certain point of the process, are better than expected, providing the possibility of improving other QoS parameters. These approaches have been implemented in service composition frameworks and evaluated through the execution of test cases. Evaluation was performed by comparing the QoS values gathered from multiple executions of composite services, using the proposed optimization models and a non-adaptive approach. The benefit of adaptation was found a useful value during the decision making process, in order to determine if adaptation was needed or not. Results show that using optimization mechanisms when executing composite services provide significant improvements in the global QoS values of the compositions. Nevertheless, in some cases there is a trade-off, where one of the measured parameters shows an increment, in order to improve the others.

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BERARDI, Daniela. "Automatic Service Composition. Models, Techniques and Tools." Doctoral thesis, La Sapienza, 2005. http://hdl.handle.net/11573/917069.

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Maesano, Ariele. "Bayesian dynamic scheduling for service composition testing." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066100/document.

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Aujourd'hui la connectivité entre les systèmes se standardise. Il supprime l'intervention humaine et permet aux systèmes distribués d'accomplir des tâches longues et complexes. La SOA est une approche fondée sur le modèle qui s'appuie sur des contrats et qui permet aux systèmes existants de collaborer par échange de messages. De multiples organisations peuvent, automatiser des échanges de services sans risquer leur confidentialité. Cette collaboration est à l'origine des difficultés concernant le test, parce que si il a des échanges entre les différents partenaires, le fonctionnement interne de processus résultant dans l'information échangé est limité à certains partenaires/testeurs. Ceci nous place dans un cadre de tests boîte grise où les systèmes sont des boîtes noires et seulement l'échange de message est visible. C'est pourquoi nous proposons une approche probabiliste en utilisant l'inférence bayésienne pour tester les SOA. Le deuxième défi est leur taille. Etant donné que les systèmes sont connectés de manière lâche en les couplant deux par deux selon les spécifications, une SOA peut contenir un nombre très important de participants et donc une grande taille. La taille des SOA se reflète dans la complexité de l'inférence bayésienne. Cette seconde contrainte pousse à chercher de meilleure solution pour l'inférence bayésienne. Afin de faire face à la taille et la densité de la BN, même pour de petits services architectures, les techniques d'inférence par compilation dirigée par les modèles qui permet la génération rapide de circuits arithmétiques directement à partir du modèle de l'architecture des services et de la suite de tests sont en cours d'élaboration In present times connectivity between systems becomes more common. It removes human mediation and allows complex distributed systems to autonomously complete long and complex tasks. SOA is a model driven contract based approach that allows legacy systems to collaborate by messages exchange. Collaboration, here, is a key word in the sense that multiple organisation can, with this approach, automate services exchanges between them without putting at risks their confidentiality. This cause to encounter the first difficulty, because if there are exchanges between the different partners, the inner-processes resulting in the exchange information is restricted to some partners and therefor to some of the testers. That put us in a grey-box testing case where the systems are black-boxes and only the message exchange is visible. That is why we propose a probabilistic approach using Bayesian Inference to test the architectures. The second Challenge is the size of the SOA. Since the systems are connected by loosely coupling them two by two according to SOA Specifications, SOA can contain a very important number of participants. In Fact most of the existing SOA are very important in there size. The size of the SOA is reflected in the complexity of the Bayesian inference. This second challenge constraints us to search for better solution for the Bayesian Inference. In order to cope with the size and density of the BN for even small services architectures, techniques of model-driven inference by compilation that allows quick generation of arithmetic circuits directly from the services architecture model and the test suite are being developed

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Maesano, Ariele. "Bayesian dynamic scheduling for service composition testing." Electronic Thesis or Diss., Paris 6, 2015. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2015PA066100.pdf.

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Huma, Zille [Verfasser]. "Automatic service discovery and composition for heterogeneous service partners / Zille Huma." Paderborn : Universitätsbibliothek, 2015. http://d-nb.info/1075807336/34.

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Zhou, J. (Jiehan). "Pervasive service computing: community coordinated multimedia, context awareness, and service composition." Doctoral thesis, Oulun yliopisto, 2011. http://urn.fi/urn:isbn:9789514296451.

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Abstract This thesis introduces a novel Web service-centric solution to pervasive computing, called Service-oriented Pervasive Computing (also called Pervasive Service Computing), which enables computer systems to deal with context in the user’s environment, to dynamically discover and compose existing services, and to develop Internet-scale multimedia applications that support users’ activities. First, this thesis introduces the concept of Pervasive Service Computing and its relation to community coordinated multimedia, context awareness, and service-oriented computing. It then investigates the state of the art, the practices, and techniques which have been developed to support such services. Building on these tools, this study adopts a service-oriented methodology to design a reference model for Pervasive Service Computing, for accommodating specified technical requirements. This model can serve as a guide for research and development towards Pervasive Service Computing. Second, the thesis examines the nature of community coordinated multimedia, and develops the concept of Community Coordinated Multimedia (CCM). To discover the potentials of discoverability and composability of multimedia applications, the thesis introduces a model for Service-oriented Community Coordinated Multimedia (SCCM), and demonstrates the idea of “multimedia application as a service.” Furthermore, the thesis presents a content annotation service and evaluates its feasibility as an end-user prototype. Third, the thesis investigates the nature of context awareness in Pervasive Service Computing, to broaden the definition of context and context-awareness. This research introduces context-aware pervasive service composition (CAPSC) applications, and specifies three-levels of context awareness. Building on this framework, the context-aware service composition prototype is implemented. Fourth, the author examines the overall potential of service composition in Pervasive Service Computing, distinguishes its two main functions as service collaboration, and service coordination, and then develops an ODPSC (Ontology-Driven Pervasive Service Composition) ontology. To address the availability and scalability of service composition, the thesis introduces options for dynamic service composition in the Cloud, and develops an accelerated Cloud architecture for service composition in the Cloud (namely CM4SC middleware). Last, the CM4SC middleware as a service prototype is implemented Tiivistelmä Tässä työssä käsitellään uutta jokapaikan tietotekniikan Web-palvelukeskeistä ratkaisua, palveluorientoitunutta jokapaikan tietotekniikkaa (Pervasive Service Computing). Tämän avulla tietokonejärjestelmät voivat ottaa huomioon käyttäjän ympäristön tilanteen, löytää ja koota palveluja dynaamisesti, ja näin voidaan kehittää Internetin laajuisia käyttäjän toimintoja tukevia multimediasovelluksia. Ensiksi työssä esitellään jokapaikan tietotekniikan palvelujen käsite sekä tällaisten palveluiden suhde yhteisöllisesti koordinoituun multimediaan, tilannetietoisuuten ja palveluorientoituneeseen tietotekniikkaan. Tieteen nykytila sekä tällaisia palveluja tukemaan kehitetyt käytännöt ja tekniikat esitellään. Näihin työkaluihin pohjautuen työssä omaksutaan palveluorientoitunut metodiikka, kun jokapaikan tietotekniikan palveluille suunnitellaan referenssimalli, jonka avulla voidaan määritellä teknisiä vaatimuksia ja joka voi muutenkin toimia ohjenuorana jokapaikan tietotekniikan palvelujen tutkimukselle ja tuotekehitykselle. Toiseksi työssä tutkitaan yhteisöllisesti koordinoidun multimedian ominaispiirteitä ja määritellään yhteisöllisesti koordinoidun multimedian (Community Coordinated Multimedia, CCM) käsite. Multimediasovellusten löydettävyyden ja kokoamisen mahdollisuuksien kartoittamiseen luodaan palveluorientoitunut CCM-malli (Service-oriented Community Coordinated Multimedia, SCCM). Työssä esitellään ”multimediasovellus palveluna” -idea, jonka käyttökelpoisuutta arvioidaan sisältöpohjaisen annotoinnin prototyyppiratkaisun avulla. Kolmanneksi työssä tutkitaan jokapaikan tietotekniikan palvelujen tilannetietoisuutta laajentamalla tilanteen ja tilannetietoisuuden määritelmiä. Tutkimus esittelee tilannetietoiseen jokapaikan tietotekniikan palvelujen kokoamiseen (Context-Aware Pervasive Service Composition, CAPSC) perustuvia sovelluksia ja määrittelee kolme tasoa tilannetietoisuudelle. Tämän viitekehyksen avulla toteutetaan tilannetietoinen palvelujen kokoamisen prototyyppi. Neljänneksi työssä arvioidaan jokapaikan tietotekniikan palvelujen kokoamisen mahdollisuuksia, tunnistetaan sen kaksi keskeistä toiminnallisuutta, palvelujen yhteistoiminnallisuus (service collaboration) ja palvelujen koordinointi (service coordination), sekä kehitetään ODPSC (Ontology-Driven Pervasive Service Composition) -ontologia. Työssä esitetään saavutettavuuden ja laajennettavuuden haasteisiin ratkaisuksi dynaaminen palvelujen kokoaminen pilvipalveluna. Työssä kehitetään kiihdytetty pilviarkkitehtuuri (CM4SC-välikerrosohjelmisto) palvelujen kokoamiseen pilvessä. Lopuksi työssä toteutetaan CM4SC-välikerrosohjelmiston palveluprototyyppi

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Medjahed, Brahim. "Semantic Web Enabled Composition of Web Services." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/27364.

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In this dissertation, we present a novel approach for the automatic composition of Web services on the envisioned Semantic Web. Automatic service composition requires dealing with three major research thrusts: semantic description of Web services, composability of participant services, and generation of composite service descriptions. This dissertation deals with the aforementioned research issues. We first propose an ontology-based framework for organizing and describing semantic Web services. We introduce the concept of community to cluster Web services based on their domain of interest. Each community is defined as an instance of an ontology called community ontology. We then propose a composability model to check whether semantic Web services can be combined together, hence avoiding unexpected failures at run time. The model defines formal safeguards for meaningful composition through the use of composability rules. We also introduce the notions of composability degree and tau-composability to cater for partial and total composability. Based on the composability model, we propose a set of algorithms that automatically generate detailed descriptions of composite services from high-level specifications of composition requests. We introduce a Quality of Composition (QoC) model to assess the quality of the generated composite services. The techniques presented in this dissertation are implemented in WebDG, a prototype for accessing e-government Web services. Finally, we conduct an extensive performance study (analytical and experimental) of the proposed composition algorithms. Ph. D.

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Amdouni, Soumaya. "Composition de services web dans des environnements incertains." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10128.

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Cette thèse porte sur la composition des services de données et l'étude de l'impact de l'incertitude qui peut être associée à leurs données accessibles sur le processus de composition et de sélection de service. En effet, dans un contexte tel que l'Internet, il est de plus en plus reconnu que les données et les services d'accès aux données sont sujettes à des valeurs d'incertitude tout en exigeant des techniques de gestion plus sophistiquées. Dans cette thèse, nous enrichissons la description sémantique des services Web afin de refléter l'incertitude, et nous proposons de nouveaux mécanismes et modèles pour la sélection et la composition des services. Nos mécanismes sont basés sur les ensembles flous et les théories probabilistes. Tout d'abord, nous étendons notre modélisation précédente basée sur les vues RDF afin d'inclure les contraintes floues qui caractérisent les données accédées par les services. Nous proposons une algèbre de composition qui permet de classer les résultats retournés en fonction de leur pertinence par rapport aux préférences de l'utilisateur. Notre algèbre proposée repose sur les fondations de bases de données floues. En outre, nous optons pour l'approche probabiliste pour modéliser l'incertitude des données renvoyées par les services incertains. Nous étendons la description du service Web standard pour représenter les probabilités de sortie. L'invocation des services est également étendue pour tenir compte de l'incertitude. Cette extension est basée sur la théorie des mondes possibles utilisée dans les bases de données probabiliste. Nous définissons un ensemble d'opérateurs de composition qui sont nécessaires pour orchestrer les services de données. Pour chaque composition, plusieurs plans d'orchestration peuvent être possibles mais qui sont pas tous corrects, donc, nous définissons un ensemble de conditions pour vérifier si le plan est correct (Safe) ou pas. Nous fournissons une implémentation de nos différentes techniques et les appliquer aux domaines de l'immobilier et du commerce électronique. Nous implémentons ces services et nous fournissons également une étude de la performance de notre prototype de composition In this thesis we focus on the data web services composition problem and study the impact of the uncertainty that may be associated with the output of a service on the service selection and composition processes. This work is motivated by the increasing number of application domains where data web services may return uncertain data, including the e-commerce, scientific data exploration, open web data, etc. We call such services that return uncertain data as uncertain services. In this dissertation, we propose new models and techniques for the selection and the composition of uncertain data web services. Our techniques are based on well established fuzzy and probabilistic database theories and can handle the uncertainty efficiently. First, we proposed a composition model that takes into account the user preferences. In our model, user preferences are modelled as fuzzy constraints, and services are described with fuzzy constraints to better characterize their accessed data. The composition model features also a composition algebra that allows us to rank the returned results based on their relevance to user's preferences. Second, we proposed a probabilistic approach to model the uncertainty of the data returned by uncertain data services. Specifically, we extended the web service description standards (e.g., WSDL) to represent the outputs' probabilities. We also extended the service invocation process to take into account the uncertainty of input data. This extension is based on the possible worlds theory used in the probabilistic databases. We proposed also a set of probability-aware composition operators that are necessary to orchestrate uncertain data services. Since a composition may accept multiple orchestration plans and not all of them compute the correct probabilities of outputs, we defined a set of conditions to check if a plan is safe (i.e., computes the probabilities correctly) or not. We implemented our different techniques and applied them to the real-estate and e-commerce domains. We provide a performance study of our different composition techniques

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Meit, Michael, Kate E. Beatty, and Megan Heffernan. "Exploring Differences between Urban and Rural LHDs: Service Composition and Financing." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etsu-works/6837.

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Omer, Abrehet Mohammed. "A framework for Automatic Web Service Composition based on service dependency analysis." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-70742.

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The practice of composing web services has received an increasing interest with the emerging application development architecture called Service Oriented Architecture (SOA). A web service composition can be done either manually or (semi-) automatically. Doing composition (semi-) automatically minimizes runtime problems that arise due to dynamic nature of runtime environments. However, the implementation of (semi-) automatic composition demands for the automation of a process model or a composition plan generation process. In addition, creating a composite service or applications from component services, that are developed and meant to work independently, causes unavoidable dependencies among the services involved. Consequently, in a composite service development, understanding, analyzing and tracking of such dependencies becomes important. This thesis views the process model generation sub-task of a service composition as a service dependency identifification and analysis problem. In this thesis, we propose a dependency based automatic process model generation methods. For this purpose, the following issues are explored. First, a top layer architecture with a composition engine is developed. The architecture gives a complete picture of dependency based automatic service composition. Second, the process model generation sub-task is formulated as a service dependency identification and analysis problem. Third, a two-stepped method for automatic process model generation, given a set of candidate web service descriptions, is proposed. The first step of the proposed approach deals with the identifification of potential direct and indirect dependencies between abstract services. The direct dependency extraction is done by assuming a semantic I/O matching of service parameters. The extraction of indirect dependency from direct dependency is done using a recursive algorithm derived from the transitive closure property. Alternatively the Warshall algorithm is used. The second step of the proposed approach deals with analysis of dependency information and generation of process model (PM) automatically. To execute this step, we propose two approaches: matrix based and graph based approaches. The matrix based approach utilizes both direct and indirect dependencies. This approach represents dependencies using matrix and takes advantages of a sorting algorithm. The matrix representation facilitates a simplistic mathematical dependency analysis for generating important indicators during automatic process model creation. The process model is generated using a sorting algorithm that uses the analysis result obtained from the dependency matrix as sorting criterion. The graph based approach uses only direct dependency among candidate services. As its name indicates, in this approach the extracted I/O dependencies are represented using a directed graph. A modifified topological sorting algorithm is used for generating a process model that shows the execution order of candidate services. Both of the proposed approaches (matrix and graph based approaches) recognize the existence of cyclic dependencies and provide ways of dealing with them. The resulting process model or composition plan from both approaches has a sequential, concurrent and loop control flows. Finally, the performance of the proposed approaches is studied theoretically as well as experimentally. For the experimental validation and evaluation purpose, the approaches are implemented in a prototype that facilitates the validation and evaluation of the approaches at a larger scale. An extensive experimental performance evaluation is done fifirst on each proposed approach. The two approaches are then compared and their pros and cons under difffferent scenarios are assessed.

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Rifai, Mohammad al [Verfasser]. "Service selection and transactional management for web service composition / Mohammad Al-Rifai." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2011. http://d-nb.info/1014254914/34.

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Vandikas, Konstantinos [Verfasser]. "A fine-grained approach towards asynchronous service composition of heterogeneous services / Konstantinos Vandikas." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2015. http://d-nb.info/107456314X/34.

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Djenouhat, Manel Amel. "Un cadre sémantique formel pour la description, sélection et composition des services web." Thesis, Paris, CNAM, 2017. http://www.theses.fr/2017CNAM1137/document.

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Le but de cette thèse est de dégager un cadre sémantique formel approprié supportant l'interopérabilité dedifférents formalismes déjà utilisés pour décrire et déployer un service Web. En d’autres termes, nouscontribuons au développement d’un formalisme mathématique rigoureux permettant de décrire un service Webcomplexe susceptible de changer pendant l’exécution et de coordonner avec les autres services de façonadaptative. Pour atteindre cet objectif, les étapes de description, de sélection et de composition ont constitué lestrois majeures problématiques étudiées dans cette thèse.Pour ce faire, nous avons proposé dans un premier temps, à travers l’utilisation du cadre sémantique formel K lelangage K-WSDL; un langage de description de services Web doté d’une sémantique opérationnelle en terme derègles de réécriture qui peut être exécutable et analysable sous Maude. Nous avons introduit, dans un secondtemps, l’approche WS-Sim basée sur la théorie des catégories qui évalue l’équivalence comportementale entreservices en représentant chaque service par une catégorie et en établissant des liens formels (foncteur) entre elles.Enfin, nous avons présenté le modèle RMop-ECATNet (Refined Meta Open ECATNet ) : un modèle dédié à laspécification formelle de la composition des services Web et fruit du raffinement du modèle Mop-ECATNetproposé par [LB14]. Nous avons étendu et enrichi ce dernier aux trois niveaux : structurel, comportemental etimplémentation The aim of this thesis is to provide a suitable formal semantic framework that supports interoperability ofdifferent formalisms already used to describe and deploy a Web service. In other words, we contribute to thedevelopment of a rigorous mathematical formalism to describe a complex Web service that may change duringexecution and coordinate with other services adaptively. To achieve this goal, the steps of description, selectionand composition constitute the three major issues studied in this thesis.We proposed so, initially, through the use of the K semantic framework the K-WSDL : a Web servicesdescription language endowed with an operational semantics in terms of rewriting rules which can be executedand analyzed in Maude. We introduced, in a second step, WS-Sim, a new approach based on the category theorywhich evaluates the behavioral equivalence between services by representing each service by a category and byestablishing formal links (functor) between them. Finally, we present RMop-ECATNet (Refined Meta OpenECATNet): a formal model for the specification of services composition. product of the refinement of the Mop-ECATNets model, introduced initially by [LB14]. We extended and enriched this model at three distinct levels:at the structural, behavioural level and implementation levels

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Lämmermann, Sven. "Runtime Service Composition via Logic-Based Program Synthesis." Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3371.

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