Dissertations / Theses on the topic 'Semantic Web Services'
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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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Gessler, Damian, Gary Schiltz, Greg May, Shulamit Avraham, Christopher Town, David Grant, and Rex Nelson. "SSWAP: A Simple Semantic Web Architecture and Protocol for semantic web services." BioMed Central, 2009. http://hdl.handle.net/10150/610154.
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BACKGROUND:SSWAP (Simple Semantic Web Architecture and Protocolpronounced "swap") is an architecture, protocol, and platform for using reasoning to semantically integrate heterogeneous disparate data and services on the web. SSWAP was developed as a hybrid semantic web services technology to overcome limitations found in both pure web service technologies and pure semantic web technologies.RESULTS:There are currently over 2400 resources published in SSWAP. Approximately two dozen are custom-written services for QTL (Quantitative Trait Loci) and mapping data for legumes and grasses (grains). The remaining are wrappers to Nucleic Acids Research Database and Web Server entries. As an architecture, SSWAP establishes how clients (users of data, services, and ontologies), providers (suppliers of data, services, and ontologies), and discovery servers (semantic search engines) interact to allow for the description, querying, discovery, invocation, and response of semantic web services. As a protocol, SSWAP provides the vocabulary and semantics to allow clients, providers, and discovery servers to engage in semantic web services. The protocol is based on the W3C-sanctioned first-order description logic language OWL DL. As an open source platform, a discovery server running at http://sswap.info webcite (as in to "swap info") uses the description logic reasoner Pellet to integrate semantic resources. The platform hosts an interactive guide to the protocol at http://sswap.info/protocol.jsp webcite, developer tools at http://sswap.info/developer.jsp webcite, and a portal to third-party ontologies at http://sswapmeet.sswap.info webcite (a "swap meet").CONCLUSION:SSWAP addresses the three basic requirements of a semantic web services architecture (i.e., a common syntax, shared semantic, and semantic discovery) while addressing three technology limitations common in distributed service systems: i.e., i) the fatal mutability of traditional interfaces, ii) the rigidity and fragility of static subsumption hierarchies, and iii) the confounding of content, structure, and presentation. SSWAP is novel by establishing the concept of a canonical yet mutable OWL DL graph that allows data and service providers to describe their resources, to allow discovery servers to offer semantically rich search engines, to allow clients to discover and invoke those resources, and to allow providers to respond with semantically tagged data. SSWAP allows for a mix-and-match of terms from both new and legacy third-party ontologies in these graphs.
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Hull, Duncan. "Semantic matching of bioinformatic web services." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497578.
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Understanding bioinformatic data on the Web often requires the interoperation of heterogeneous and autonomous services. Unfortunately, getting many different services to interoperate is problematic, and frequently requires cumbersome shim components which can be difficult to describe and discover using existing techniques. The use of description logic reasoning has been proposed as a method for improving discovery of services, by classifying advertisements and matchmaking them with requests on the semantic Web. However, theoretical approaches to reasoning with semantic Web services have not been adequately tested on realistic scenarios while practical approaches have not fully investigated or applied useful aspects of current theory.
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Alfaries, Auhood. "Ontology learning for Semantic Web Services." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/4667.
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The expansion of Semantic Web Services is restricted by traditional ontology engineering methods. Manual ontology development is time consuming, expensive and a resource exhaustive task. Consequently, it is important to support ontology engineers by automating the ontology acquisition process to help deliver the Semantic Web vision. Existing Web Services offer an affluent source of domain knowledge for ontology engineers. Ontology learning can be seen as a plug-in in the Web Service ontology development process, which can be used by ontology engineers to develop and maintain an ontology that evolves with current Web Services. Supporting the domain engineer with an automated tool whilst building an ontological domain model, serves the purpose of reducing time and effort in acquiring the domain concepts and relations from Web Service artefacts, whilst effectively speeding up the adoption of Semantic Web Services, thereby allowing current Web Services to accomplish their full potential. With that in mind, a Service Ontology Learning Framework (SOLF) is developed and applied to a real set of Web Services. The research contributes a rigorous method that effectively extracts domain concepts, and relations between these concepts, from Web Services and automatically builds the domain ontology. The method applies pattern-based information extraction techniques to automatically learn domain concepts and relations between those concepts. The framework is automated via building a tool that implements the techniques. Applying the SOLF and the tool on different sets of services results in an automatically built domain ontology model that represents semantic knowledge in the underlying domain. The framework effectiveness, in extracting domain concepts and relations, is evaluated by its appliance on varying sets of commercial Web Services including the financial domain. The standard evaluation metrics, precision and recall, are employed to determine both the accuracy and coverage of the learned ontology models. Both the lexical and structural dimensions of the models are evaluated thoroughly. The evaluation results are encouraging, providing concrete outcomes in an area that is little researched.
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Gooneratne, Nalaka Dilshan, and s3034554@student rmit edu au. "Discovery and Validation for Composite Services on the Semantic Web." RMIT University. Computer Science and Information Technology, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091019.155524.
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Current technology for locating and validating composite services are not sufficient due to the following reasons. Current frameworks do not have the capacity to create complete service descriptions since they do not model all the functional aspects together (i.e. the purpose of a service, state transitions, data transformations). Those that deal with behavioural descriptions are unable to model the ordering constraints between concurrent interactions completely since they do not consider the time taken by interactions. Furthermore, there is no mechanism to assess the correctness of a functional description. Existing semantic-based matching techniques cannot locate services that conform to global constraints. Semantic-based techniques use ontological relationships to perform mappings between the terms in service descriptions and user requests. Therefore, unlike techniques that perform either direct string matching or schema matching, semantic-based approaches can match descriptions created with different terminologies and achieve a higher recall. Global constraints relate to restrictions on values of two or more attributes of multiple constituent services. Current techniques that generate and validate global communication models of composite services yield inaccurate results (i.e. detect phantom deadlocks or ignore actual deadlocks) since they either (i) do not support all types of interactions (i.e. only send and receive, not service and invoke) or (ii) do not consider the time taken by interactions. This thesis presents novel ideas to deal with the stated limitations. First, we propose two formalisms (WS-ALUE and WS-π-calculus) for creating functional and behavioural descriptions respectively. WS-ALUE extends the Description Logic language ALUE with some new predicates and models all the functional aspects together. WS-π-calculus extends π-calculus with Interval Time Logic (ITL) axioms. ITL axioms accurately model temporal relationships between concurrent interactions. A technique comparing a WS-π-calculus description of a service against its WS-ALUE description is introduced to detect any errors that are not equally reflected in both descriptions. We propose novel semantic-based matching techniques to locate composite services that conform to global constraints. These constraints are of two types: strictly dependent or independent. A constraint is of the former type if the values that should be assigned to all the remaining restricted attributes can be uniquely determined once a value is assigned to one. Any global constraint that is not strictly dependent is independent. A complete and correct technique that locates services that conform to strictly dependent constraints in polynomial time, is defined using a three-dimensional data cube. The proposed approach that deals with independent constraints is correct, but not complete, and is a heuristic approach. It incorporates user defined objective functions, greedy algorithms and domain rules to locate conforming services. We propose a new approach to generate global communication models (of composite services) that are free of deadlocks and synchronisation conflicts. This approach is an extension of a transitive temporal reasoning mechanism.
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Bennara, Mahdi. "Linked service integration on the semantic web." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI055.
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L'informatique orientée services facilite l'interopérabilité entre les systèmes distribues. Depuis quelques années, l'émergence du Web sémantique a pose de nouveaux défis pour la communauté de recherche dans les calculs et la compatibilité sémantique des données. L'approche « services » et le Web sémantique constituent une piste prometteuse pour remédier aux problèmes qui entravent les deux domaines. D'une part l'orientation services permet d'assurer l'interopérabilité des données et des traitements au niveau sémantique, et d'autre part le Web sémantique permet d'automatiser les taches de manipulation de services à un haut niveau. Dans le cadre de notre travail de recherche, nous avons détaillé les défis que rencontre la communauté de chercheurs dans l'intégration des pratiques de l'orientation services dans le Web sémantique, et plus particulièrement l'intégration des services REST dans l'implémentation du Web qui repose sur les principes du « Linked Data » pour constituer ce que l'on appelle les « RESTful Linked Services ». Les défis en question sont : La description, la découverte, la sélection et la composition. Nous avons proposé une solution pour chacun de ces défis. Les contributions que nous avons proposées sont : la structure de descripteur, un algorithme de découverte sémantique, un algorithme de sélection base sur Skyline et les répertoires de composition. Nous pensons que l'ensemble de contributions que nous avons proposées peut être adopte par les fournisseurs de services sur le Web afin de faciliter l'intégration des pratiques du sémantique Web avec les technologies des services et de REST en particulier. Ceci permettra donc d'automatiser les taches de manipulation de services a un haut niveau, tel que la découverte sur la base de concepts sémantiques, la sélection sur la base de propriétés non-fonctionnelles et de qualité de services et la composition de plusieurs services hétérogènes, sur le plan des données ainsi que sur le plan des traitements, afin d'obtenir des services composites avec de la valeur ajoutéeService Oriented Computing allows interoperability between distributed systems. In the last years, the emergence of the semantic Web opened new challenges for the research community regarding semantic interoperability on the data and processing levels. The convergence of service orientation and the semantic Web together is a promising effort to solve the problems that hampered both research fields. On the one hand, service orientation allows interoperability on the data and processing levels, and on the other hand, semantic Web allows the automation of high-level service manipulation tasks. In our research, we detail the challenges encountered by the research community to integrate the service orientation practices with the semanticWeb, more precisely, integrating REST-based services with the semantic Web implementation based on Linked Data principles to obtain RESTful Linked Services. The challenges in question are : description, discovery, selection and composition. We proposed a solution for each of these challenges. The contributions we proposed are : The descriptor structure, a semantically-enabled discovery algorithm, a Skyline-based selection algorithm and composition directories. We think that these contributions can be adopted by service providers on the Web in order to allow a seamless integration of semantic Web practices with the service technologies and REST in particular. This allows the automation of high-level service manipulation tasks, such as semantically-enabled discovery, QoS-based selection and the composition of heterogeneous services, be it on the data or processing level, in order to create value-added composite services
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Kardas, Karani. "Semantic Processes For Constructing Composite Web Services." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608715/index.pdf.
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In Web service composition, service discovery and combining suitable services through determination of interoperability among different services are important operations. Utilizing semantics improves the quality and facilitates automation of these operations. There are several previous approaches for semantic service discovery and service matching. In this work, we exploit and extend these semantic approaches in order to make Web service composition process more facilitated, less error prone and more automated. This work includes a service discovery and service interoperability checking technique which extends the previous semantic matching approaches. In addition to this, as a guidance system for the user, a new semantic domain model is proposed that captures semantic relations between concepts in various ontologies.
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CONDACK, JOAO FELIPE SANTOS. "SWELL: A SEMANTIC WEB-SERVICES SELECTION ENVIRONMENT." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=5671@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROInicialmente a Internet era um canal de comunicação e distribuição de conteúdo textual. Com o advento do comércio eletrônico e a maturação da própria Web, ela se tornou uma plataforma de implantação de sistemas. Paralelamente, o próprio desenvolvimento de software evoluiu, com aplicações de novos conceitos da engenharia de software, tais como componentes, reuso e design patterns. No intuito de desenvolver práticas e tecnologias que aperfeiçoem a construção de softwares decidiu-se, neste trabalho, por conciliar estas duas tendências evolutivas. Swell é um ambiente para o auxílio no desenvolvimento de Sistemas Baseados na Web (SBWs), tendo como ponto forte a seleção semântica de web services. Trata-se de uma ferramenta cujo objetivo é ajudar nas tarefas de design e construção de aplicações, visando atingir alto grau de reuso. Este auxílio se dá através da descrição, busca e escolha de serviços para composição de aplicações. O ambiente Swell foi pensado de modo a dar suporte à evolução das tecnologias de componentes para Web. Ele provê pontos de flexibilização permitindo adaptação a novas descrições de web services e refletindo estas mudanças no mecanismo de busca.
Initially the Internet was a communication channel and a text-based content dissemination vehicle. With the advent of e-commerce and Web's unfolding, it became a systems deployment platform. At the same time, software development also evolved, through the use of new software engineering concepts, such as components, reuse and design patterns. This work aims at helping to develop practices and technologies that improve software development by conciliating these two evolution trends. Swell is an environment that helps Web Based Systems development, having as a cornerstone the semantic selection of web- services. It is a tool whose objective is to help in the application design and development tasks, aiming to reach a high degree of reuse. This is achieved through the support for the description, search and selection of web services for application composition. The Swell environment was conceived as a framework with support for the evolution of web components technologies. It provides hot spots that allow for adaptation of new web services descriptions and reflection of these changes in the search engine.
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Buttler, David John. "Building blocks for composable web services." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180046/unrestricted/buttler%5Fdavid%5F200312%5Fphd.pdf.
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Ziembicki, Joanna. "Distributed Search in Semantic Web Service Discovery." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/1103.
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This thesis presents a framework for semantic Web Service discovery using descriptive (non-functional) service characteristics in a large-scale, multi-domain setting. The framework uses Web Ontology Language for Services (OWL-S) to design a template for describing non-functional service parameters in a way that facilitates service discovery, and presents a layered scheme for organizing ontologies used in service description. This service description scheme serves as a core for desigining the four main functions of a service directory: a template-based user interface, semantic query expansion algorithms, a two-level indexing scheme that combines Bloom filters with a Distributed Hash Table, and a distributed approach for storing service description. The service directory is, in turn, implemented as an extension of the Open Service Discovery Architecture. The search algorithms presented in this thesis are designed to maximize precision and completeness of service discovery, while the distributed design of the directory allows individual administrative domains to retain a high degree of independence and maintain access control to information about their services.
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Ren, Wei. "Dynamic Self-healing for Composite Services using Semantic Web Service Technology." Thesis, Griffith University, 2009. http://hdl.handle.net/10072/366899.
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Service-Oriented Architecture (SOA) has emerged as a promising paradigm for building loosely coupled, standard-based and Web-enabled distributed applications and systems. The essential notion and technology of SOA is Web service which is the high level of abstraction of functionality with well-defined interfaces. If a Web service is further equipped with well-defined semantics, it is termed Semantic Web service. With the power of Semantics of Web services, SOA has created many new opportunities to meet the challenge of enterprise integration and provides great potentials for automated integration. However, this promising paradigm has also imposed a great challenge to the service discovery, invocation, composition, self-healing capability and so on. Among all those issues, service composition, which is defined as aggregation of other services to provide a more sophisticated, value-added service, is at the core of many applications of Web services. From a service oriented perspective, application integration which is a long standing issue in industry can be achieved via service composition. Nevertheless, the dynamics in real application context when addressing the service composition very much complicate the matter, and it is often desirable to accomplish composition with high degree of serviceability, especially when environment changes or when services previously used becomes unavailable. One of approaches to serviceability is the capability of self-healing with less or no external interventions when changes occur. Service composition and self healing of composite services are the major concerns of the research work described in this thesis. The main objectives are to extensively explore semantics for facilitating Web service composition and for realizing dynamic self-healing for composite services in a semantic-enhanced service-oriented manufacturing Collaborative Virtual Enterprise (CVE).
A CVE is a temporary alliance of enterprises to share skills or core competencies and resources in order to better respond to business opportunities in a more collaborative rather than competitive manner. Dynamism is a salient feature of CVE. A CVE needs to be dynamically formulated, its business processes need to be dynamically configured and executed to respond to the dynamic market. A CVE needs to quickly integrate its systems, applications, and services to fulfill its business goals. Taking semantic Web service-oriented approach, we shall first establish a semantic rich service-oriented manufacturing CVE where a collection of Semantic Web services are developed.
Within the service-oriented paradigm, two different approaches – BPEL and OWL-S are investigated to realize service composition in a service-oriented manufacturing CVE. The critical analysis of BPEL and OWL-S is conducted in the manufacturing CVE scenario. Five key criteria for evaluating technologies of service composition are identified. Moreover, semantic-driven services composer based on OWL-S is developed and the goal-oriented forward-chaining algorithm is presented.
In order to systematically address semantic web service composition, a business rule enhanced semantic service composition framework is further presented and analyzed. We adopt the divide-and-conquer strategy and propose a hierarchical composition architecture to handle tasks of complex service composition. In this framework, the description of each Web Service is enhanced with rule-based modeling of the essential business logic behind the service interface. A formal notion of service utilities has been provided. Complete processes for calculating the service utilities have also been introduced through processing and evaluating these business rules. A PC manufacturing CVE derived from a practical industrial setting is designed and a prototype system is developed to experimentally evaluate the effectiveness of our service composition framework.
In a practical industrial setting, the effective and efficient service composition is often not sufficient for dynamic natures of CVE. Once formulated, a composite service for a business goal must be able to address many dynamic changing issues, and in this case self-healing capability of a composite service has appeared as an attractive approach. Self-healing refers to a capability of a service to maintain its serviceability by healing itself when its component service becomes unavailable or downgraded. In this research, a self-healing capable composite service execution system is proposed. The execution system takes advantage of the complementary strengths of OWL-S and BPEL in the following ways: (1) a dynamic self-healing mechanism is proposed which can dynamically identify suitable alternatives and replace faulty services such that a composite service can be performed successfully despite of unexpected exceptions; (2) an OWL-S process to BPEL process Mapper is presented which can translate OWL-S process to BPEL process and meanwhile embed the self-healing mechanism into BPEL workflow. Semantic Web service technology plays its part for service matching and selection during the self-healing process in a sense that Semantic Web services are equipped with rich business rules in a domain-dependent manner. A concrete scenario – PC manufacturing CVE is used to demonstrate the effectiveness of self-healing capable composite service execution system.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Information and Communication Technology
Science, Environment, Engineering and Technology
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Nistad, Olav. "Semantic Web Services in a Network Management System." Thesis, Norwegian University of Science and Technology, Department of Telematics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9039.
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Semantic Web Services (SWS) are a facility towards full automation of service usage, providing seamless integration of services that are published and accessible on the Web. Based on Semanic Web technology SWS is simply a semantic annotation of the functionalitites and interfaces of Web Services. In the very same way that ontologies and metadata lanaguages will facilitate the integration of static data on the Web, the annotation of services wil help to facilitate the automation of service discovery, service composition, service contracting, and execution.In this thesis we demonstrate how SWS technology can be applied to a network management system (NMS), which can install SNMP managers during run-time in systems running TAPAS platform. Several reasoning applications are made and integrated with the existing system. In addition, we specify a set of Semantic Web Services described using OWL-S, in order to execute these applications.
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Alowisheq, Areeb. "EXPRESS : resource-oriented and RESTful Semantic Web services." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/371761/.
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This thesis investigates an approach that simplifies the development of Semantic Web services (SWS) by removing the need for additional semantic descriptions. The most actively researched approaches to Semantic Web services introduce explicit semantic descriptions of services that are in addition to the existing semantic descriptions of the service domains. This increases their complexity and design overhead. The need for semantically describing the services in such approaches stems from their foundations in service-oriented computing, i.e. the extension of already existing service descriptions. This thesis demonstrates that adopting a resource-oriented approach based on REST will, in contrast to service-oriented approaches, eliminate the need for explicit semantic service descriptions and service vocabularies. This reduces the development efforts while retaining the significant functional capabilities. The approach proposed in this thesis, called EXPRESS (Expressing RESTful Semantic Services), utilises the similarities between REST and the Semantic Web, such as resource realisation, self-describing representations, and uniform interfaces. The semantics of a service is elicited from a resource’s semantic description in the domain ontology and the semantics of the uniform interface, hence eliminating the need for additional semantic descriptions. Moreover, stub-generation is a by-product of the mapping between entities in the domain ontology and resources. EXPRESS was developed to test the feasibility of eliminating explicit service descriptions and service vocabularies or ontologies, to explore the restrictions placed on domain ontologies as a result, to investigate the impact on the semantic quality of the description, and explore the benefits and costs to developers. To achieve this, an online demonstrator that allows users to generate stubs has been developed. In addition, a matchmaking experiment was conducted to show that the descriptions of the services are comparable to OWL-S in terms of their ability to be discovered, while improving the efficiency of discovery. Finally, an expert review was undertaken which provided evidence of EXPRESS’s simplicity and practicality when developing SWS from scratch.
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Konduri, Aparna. "CLustering of Web Services Based on Semantic Similarity." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1199657471.
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Elgedawy, Islam Moukhtar, and islam_elgedawy@yahoo com au. "Correctness-Aware High-Level Functional Matching Approaches For Semantic Web Services." RMIT University. Computer Science and Information Technology, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070511.162143.
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Existing service matching approaches trade precision for recall, creating the need for humans to choose the correct services, which is a major obstacle for automating the service matching and the service aggregation processes. To overcome this problem, the matchmaker must automatically determine the correctness of the matching results according to the defined users' goals. That is, only service(s)-achieving users' goals are considered correct. This requires the high-level functional semantics of services, users, and application domains to be captured in a machine-understandable format. Also this requires the matchmaker to determine the achievement of users' goals without invoking the services. We propose the G+ model to capture the high-level functional specifications of services and users (namely goals, achievement contexts and external behaviors) providing the basis for automated goal achievement determination; also we propose the concepts substitutability graph to capture the application domains' semantics. To avoid the false negatives resulting from adopting existing constraint and behavior matching approaches during service matching, we also propose new constraint and behavior matching approaches to match constraints with different scopes, and behavior models with different number of state transitions. Finally, we propose two correctness-aware matching approaches (direct and aggregate) that semantically match and aggregate semantic web services according to their G+ models, providing the required theoretical proofs and the corresponding verifying simulation experiments.
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Åberg, Cécile. "An Evaluation Platform for Semantic Web Technology." Doctoral thesis, Linköpings universitet, IISLAB - Laboratoriet för intelligenta informationssystem, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7904.
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The vision of the Semantic Web aims at enhancing today's Web in order to provide a more efficient and reliable environment for both providers and consumers of Web resources (i.e. information and services). To deploy the Semantic Web, various technologies have been developed, such as machine understandable description languages, language parsers, goal matchers, and resource composition algorithms. Since the Semantic Web is just emerging, each technology tends to make assumptions about different aspects of the Semantic Web's architecture and use, such as the kind of applications that will be deployed, the resource descriptions, the consumers' and providers' requirements, and the existence and capabilities of other technologies. In order to ensure the deployment of a robust and useful Semantic Web and the applications that will rely on it, several aspects of the technologies must be investigated, such as whether the assumptions made are reasonable, whether the existing technologies allow construction of a usable Semantic Web, and the systematic identification of which technology to use when designing new applications. In this thesis we provide a means of investigating these aspects for service discovery, which is a critical task in the context of the Semantic Web. We propose a simulation and evaluation platform for evaluating current and future Semantic Web technology with different resource sets and consumer and provider requirements. For this purpose we provide a model to represent the Semantic Web, a model of the evaluation platform, an implementation of the evaluation platform as a multi-agent system, and an illustrative use of the platform to evaluate some service discovery technology in a travel scenario. The implementation of the platform shows the feasibility of our evaluation approach. We show how the platform provides a controlled setting to support the systematic identification of bottlenecks and other challenges for new Semantic Web applications. Finally, the evaluation shows that the platform can be used to assess technology with respect to both hardware issues such as the kind and number of computers involved in a discovery scenario, and other issues such as the evaluation of the quality of the service discovery result.
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Batouche, Brahim. "Complex Web request resolution by semantic Web service composition and multi-objecive optimization." Le Havre, 2012. http://www.theses.fr/2012LEHA0006.
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Le commerce électronique est une forme nouvelle de commerce qui prend de plus en plus d'importance dans diérents domaines, comme le tourisme, le transport, etc. Avec la généralisation d'Internet et des systèmes de télécommunication, les utilisateurs deviennent plus exigeants et souhaitent pouvoir exprimer et obtenir des réponses à des requêtes plus complexes, contenant de multiples fonctionnalités, des conditions, des contraintes et des objectifs. Techniquement, la réponse à de telles requêtes est di cilement fournie par un seul service, mais plutôt par une combinaison de services. Le problème est alors de trouver les bonnes combinaisons en utilisant les services disponibles, mais aussi de sélectionner les meilleures d'entre elles en fonction des contraintes et des objectifs exprimés dans la requête. Cette thèse a pour ambition de contribuer à résoudre ce problème en se focalisant sur la composition de services Web sémantiques et l'optimisation de la réponse à une requête complexe. Nous formalisons le problème ainsi que ses éléments: requête, services et composition. Alors que les services Web sont décrits sémantiquement en utilisant le standard OWL-S, nous présentons une ontologie compatible pour la description sémantique de la requête, que nous nommons OWL-CR. Pour la conception automatique de la composition de services qui satisfait une requête, nous proposons un nouveau modèle pour la représentation de la composition de services Web sémantiques et un algorithme qui construit des compositions basées sur ce modèle. Ce dernier prend en charge n'importe quel type de structure de la composition et permet l'exécution des compositions. Selon l'existence de dépendances entre les fonctionnalités de la requête, il peut prendre deux formes diérentes. Dans le cas de fonctionnalités dépendantes une à une ou indépendantes, l'ensemble des compositions répondant à la requête est modélisé comme un graphe multicouches. Dans le cas spécique d'une dépendance globale, l'ensemble des compositions est modélisé comme un ensemble de grappes an d'éviter l'explosion combinatoire induite par les dépendances lors de la construction du graphe de composition. Lorsque le modèle de composition est un graphe, le problème d'optimisation de la composition est déni comme un problème de recherche de plus court chemin multi-objectif et une approche exacte, comme l'algorithme de Martins que nous avons implémenté, peut être utilisée pour déterminer un sous-ensemble du front de Pareto. Les algorithmes génétiques peuvent être utilisés lorsque le modèle de composition est un ensemble de grappes, car l'ensemble des solutions ne peut pas être déni à priori et l'utilisation de tels algorithmes est nécessaire, an d'améliorer la qualité des réponses pour se rapprocher des solutions optimales. Nous expérimentons les approches NSGA2 et SPEA2, connues dans la littérature pour fournir les meilleurs résultats en termes de diversité des solutions et de niveau d'optimalité, et nous montrons qu'elles fournissent une solution acceptable. L'algorithme de composition couplé aux méthodes d'optimisation précitées à été évalué sur un scénario de composition dun voyage touristique. Les compositions obtenues contiennent des services répondant à toutes les fonctionnalités de la requête, et tiennent compte des conditions, contraintes et objectifs. Lorsque seules les structures de type séquence sont considérées, l'algorithme de conception des compositions a une complexité linéaire en fonction de services disponibles. Lorsque toutes les structures possibles sont considérées, il a une complexité cubique, mais cette prise en compte fournir un espace de solutions plus richeElectronic commerce is a new form of trade that takes increasingly important in various elds, such as tourism, transport, etc. With the spread of the Internet and telecommunication systems, users become more demanding and want to express and get answers to more complex requests, including multiple functionalities, conditions, constraints and objectives. Most complex requests including multiple functionalities cannot usually be answered by one single Web service. As multiple services are needed, the problem is then to nd good combinations using the available services but also to select the best ones according to user constraints and to the objectives expressed in the request. This thesis contributes to resolving this issue by focusing on the problem of semantic Web service composition and optimization to answer such requests. We provide some formalization of the problem and its elements : request, services and composition. While Web services are described semantically using the W3C OWL-S ontology, we design a compatible ontology for the semantic description of the request, which we name OWL-CR. For the automatic design of service composition satisfying a request, we propose a new model for the representation of semantic Web service composition and an algorithm that builds compositions based on this model. This latter supports any kind of composition structure and allows the execution of the compositions. Depending on the existence of dependencies between functionalities of the request, it can take two dierent forms. If the functionalities are independent or in the case of one-to-one dependencies only, the set of compositions answering the request is modeled as a multi-layer graph. In the specic case of global dependencies, it is modeled as a set of clusters, to avoid the combinatory problem induced by the dependencies when building the compositions with a graph. When the composition model is a graph, the problem of composition optimization is dened as a multi-objective shortest path problem and and exact approach, such as Martins'algorithm that we implemented, can be used to determine a subset of the Pareto front. Genetic Algorithms can be used in the case of global dependencies, when the composition model is a cluster set. In this case, the set of solutions cannot be dened apriori and the use of such algorithms is suitable to improve the quality of the responses to approximate optimal solutions. We experiment with the NSGA2 and SPEA2 approaches, known in the literature to provide the best results in terms of diversity of solutions and optimality level, and we show that they provide an acceptable solution. In our prototype, we have implemented our algorithm for building compositions and useful/pertinent optimization methods. The use case concerns tourism scenarios. The resulting compositions contain services fullling all request functionalities, considering the request conditions and constraints. When only the sequence structures are considered, the proposed algorithm of composition design has linear complexity in term of available services. Otherwise, it has cubic complexity, but considering all structures of composition provides a richer space of solutions
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Ozyonum, Muge. "Semantic Service Discovery With Heuristic Relevance Calculation." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/2/12611644/index.pdf.
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In this thesis, a semantically aided web service and restful service
search mechanism is presented that makes use of an ontology. The
mechanism relates method names, input and output parameters for
ontology guided matches and offers results with varying relevance
corresponding to the matching degree. The mechanism is demonstrated using an experimental domain that is tourism and travel. An ontology is created to support a set of web services that exist in this domain.
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Ouzzani, Mourad. "Efficient Delivery of Web Services." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/27360.
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This dissertation addresses issues for the efficient access to Web databases and services. We propose a distributed ontology for a meaningful organization of and efficient access to Web databases. Next, we dedicate most of our work on presenting a comprehensive query infrastructure for the emerging concept of Web services. The core of this query infrastructure is to enable the efficient delivery of Web services based on the concept of Quality of Web Service. Treating Web services as first class objects is a fundamental step towards achieving the envisioned Semantic Web. Semantics-aware processing of information requires intensive use of Web services. In our research, we propose a new query model where queries are resolved by combining Web service invocations. To efficiently deploy such scheme, we propose an optimization strategy based on aggregating Quality of Web service (QoWS) of different Web services. QoWS is adjusted through a dynamic rating scheme and multilevel matching. Web service rating provides an assessment of their behavior. The multilevel matching allows a larger solution space by enabling similar and partial answers.Ph. D.
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Sauvinet, James A. "Semantic Services for Enterprise Data Exchange." ScholarWorks@UNO, 2013. http://scholarworks.uno.edu/td/1783.
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Data exchange between different information systems is a complex issue. Each system, designed for a specific purpose, is defined using a vocabulary of the specific business. While Web services allow interoperations and data communications between multiple systems, the clients of the services must understand the vocabulary of the targeting data resources to select services or to construct queries. In this thesis we explore an ontology-based approach to facilitate clients’ queries in the vocabulary of the clients’ own domain, and to automate the query processing. A governmental inter-department data query process has been used to illustrate the capability of the semantic approach.
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Jin, Yuan. "Bridging the ontological gap between semantic web and the RESTful web services." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97115.
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Data are produced in large quantities and in various forms around the globe everyday. Researchers advance their research depending on the availability of necessary data and the discovery of them. As people's demand to manage the data grows, however, three problems appear to hinder the attempts to effectively leverage the data. One is the semantic heterogeneity found in linking different data sources. Database designers create data with different semantics; even data within the same domain may differ in meaning. If users want to acquire all the obtainable information, they have to write different queries with different semantics. One solution to such a problem is the use of ontology. An ontology is defined as a specification for the concepts of an agent (or a community of agents) and the relationships between them (Gruber 1995). Concepts and relationships between concepts are extracted from the data to form knowledge network. Other parties wishing to connect their data to the knowledge network could share, enrich and distribute the vocabulary of the ontology. Users could also write queries to the ontology by any RDF query language (Brickly 2004). The use of ontology is part of the Web 3.0's effort to provide a semantic-sensitive global knowledge network. A second problem is about new ways to access data resources with ontology information. People used to build application-specific user interfaces to databases, which were offline. Now many choose to expose data in Web Services. Web services are a system to provide HTTP-based remote request calling services that are described in a machine-readable format (Haas and Brown 2004). They usually provide application (or web) programming interfaces to manage data. The question is Web Services are born in a world of applications relying on conventional ways to connect to data sources. For example, D2RQ (Bizer and Seaborne 2004) translates queries against ontology to SQL queries and it depends on JDBC to read from relational databases. Now the interfaces for these data sources are going to be changed. The Semantic Web world faces the challenge to lose data sources. If Web Services were going to spread over the Internet one day, this lack of connection would hold back me from applying the ontology to connect to heterogeneous data sources.A third problem (or constraint) is working within the specific project domain. I embed this within a humanities cyberinfrastructure that integrates Chinese biographical, historical and geographical data. The data sources come in various forms – local and remote relational databases and, RESTful Web Services. Working with both legacy databases and the new web application interfaces narrowed down my choice of solutions. Commercial products provide ways to "ontologicalize" the Web Services. I argue that they are heavyweight (e.g. unnecessary components bound with the product) and cost-prohibitive for small-scale projects like ours. Several mature open source solutions featuring working with relational databases provide no or very limited access to Web Services. For example, no clue is found in D2RQ to join Web Services into their system, while OpenLink Virtuoso answers calls for SOAP but cannot manage data from RESTful Web Services. I propose to build a connection between ontologies and Web Services. I devise the metadata to represent non-RDF Web Services in ontology, and I revise the code and create new data structures in D2RQ to support ontology queries to data from RESTful Web Services.Les données sont produites en grandes quantités et sous diverses formes dans le monde et tous les jours. Les chercheurs avancer leurs recherches en fonction de la disponibilité des données nécessaires et la découverte de leur. Comme la demande des gens pour gérer les données croît, toutefois, trois problèmes semblent entraver les tentatives d'exploiter efficacement les données. La première est l'hétérogénéité sémantique dans reliant différentes sources de données. Concepteurs de créer des données de base de données avec une sémantique différente; même les données dans le même domaine peuvent avoir une signification différente. Si les utilisateurs souhaitent obtenir toute l'information obtenue, ils doivent écrire des requêtes différentes avec une sémantique différente. Une solution à ce problème est l'utilisation de l'ontologie. Une ontologie est définie comme une spécification pour les concepts d'un agent (ou d'une communauté d'agents) et les relations entre eux (Gruber 1995). Concepts et les relations entre les concepts sont extraites des données pour former réseau de connaissances. Les autres parties qui souhaitent se connecter leurs données au réseau de connaissances pourraient partager, enrichir et diffuser le vocabulaire de l'ontologie. Les utilisateurs peuvent aussi écrire des requêtes à l'ontologie par une requête RDF langue (Brickley 2004). L'utilisation de l'ontologie est une partie de l'effort de Web 3.0 pour fournir un réseau de connaissances sémantiques sensibles mondiale.Un deuxième problème est sur le point de nouvelles façons d'accéder aux données des ressources de l'information ontologie. Les gens de construire des interfaces utilisateur des applications spécifiques aux bases de données, qui ont été mises hors. Maintenant, de nombreux fournisseurs de données choisir pour exposer les données des services web. Les services web sont un système pour fournir la demande HTTP à distance d'appeler les services qui sont décrits dans un format lisible par machine (Haas and Brown 2004). Par exemple, D2RQ (Bizer and Seaborne 2004) se traduit par des requêtes sur l'ontologie de requêtes SQL, et cela dépend de JDBC pour lire à partir des bases de données relationnelles. Maintenant, les interfaces de ces sources de données vont être modifiées. Le monde du web sémantique doit relever le défi de perdre des sources de données. Si les services web ont été va se répandre sur Internet, un jour, ce manque de connexion tiendrait nous ramène de l'application de l'ontologie de se connecter à des sources de données hétérogènes.Un troisième problème (ou contrainte) est travailler dans le domaine des projets spécifiques. Nous incorporer cela dans une cyber-infrastructure qui intègre les sciences humaines chinois biographiques, des données historiques et géographiques. Les sources de données prennent des formes diverses - bases de données locales et distantes relationnelles et, les services web RESTful. Travailler avec les anciennes bases de données à la fois et l'application web de nouvelles interfaces rétréci vers le bas notre choix de solutions. Produits commerciaux offrent des moyens à ontologicalize les services web. Nous soutenons qu'ils sont lourds (par exemple, les composants inutiles liés au produit) et ils sont coûteuse pour les projets à petite échelle, comme notre projet. Plusieurs solutions open source mature offrant de travailler avec des bases de données relationnelles ne fournissent pas ou peu accès aux services Web. Nous proposons de construire un lien entre les ontologies et les services web. Nous trouver les métadonnées pour représenter les non-RDF services web dans l'ontologie, et nous revoir le code et créer de nouvelles structures de données en D2RQ à l'appui des requêtes ontologie à partir des données des services web RESTful.
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Thakker, Dhavalkumar. "An intelligent framework for dynamic web services composition in the semantic web." Thesis, Nottingham Trent University, 2008. http://irep.ntu.ac.uk/id/eprint/145/.
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As Web services are being increasingly adopted as the distributed computing technology of choice to securely publish application services beyond the firewall, the importance of composing them to create new, value-added service, is increasing. Thus far, the most successful practical approach to Web services composition, largely endorsed by the industry falls under the static composition category where the service selection and flow management are done a priori and manually. The second approach to web-services composition aspires to achieve more dynamic composition by semantically describing the process model of Web services and thus making it comprehensible to reasoning engines or software agents. The practical implementation of the dynamic composition approach is still in its infancy and many complex problems need to be resolved before it can be adopted outside the research communities. The investigation of automatic discovery and composition of Web services in this thesis resulted in the development of the eXtended Semantic Case Based Reasoner (XSCBR), which utilizes semantic web and AI methodology of Case Based Reasoning (CBR). Our framework uses OWL semantic descriptions extensively for implementing both the matchmaking profiles of the Web services and the components of the CBR engine. In this research, we have introduced the concept of runtime behaviour of services and consideration of that in Web services selection. The runtime behaviour of a service is a result of service execution and how the service will behave under different circumstances, which is difficult to presume prior to service execution. Moreover, we demonstrate that the accuracy of automatic matchmaking of Web services can be further improved by taking into account the adequacy of past matchmaking experiences for the requested task. Our XSCBR framework allows annotating such runtime experiences in terms of storing execution values of non-functional Web services parameters such as availability and response time into a case library. The XSCBR algorithm for matchmaking and discovery considers such stored Web services execution experiences to determine the adequacy of services for a particular task. We further extended our fundamental discovery and matchmaking algorithm to cater for web services composition. An intensive knowledge-based substitution approach was proposed to adapt the candidate service experiences to the requested solution before suggesting more complex and computationally taxing AI-based planning-based transformations. The inconsistency problem that occurs while adapting existing service composition solutions is addressed with a novel methodology based on Constraint Satisfaction Problem (CSP). From the outset, we adopted a pragmatic approach that focused on delivering an automated Web services discovery and composition solution with the minimum possible involvement of all composition participants: the service provider, the requestor and the service composer. The qualitative evaluation of the framework and the composition tools, together with the performance study of the XSCBR framework has verified that we were successful in achieving our goal.
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Skytøen, Øyvind. "Semantic Web Services: an Evaluation of a Framework Implementation." Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8881.
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The World Wide Web has become a vast and often chaotic source of all sorts of information and services. Computers have become the tool of the modern knowledge worker, and the Web constitutes both office and library. The current tools of the Web are unable to utilize its full potential, which limits the efficiency of the knowledge workers. The goal of the Semantic Web, and Semantic Web Services, is to solve this problem by introducing an evolution of the Web that is understandable for machines and humans. The objective of this master thesis was to extend the evaluation in my project on Semantic Web Services frameworks from fall 2007, by evaluating a framework implementation. The evaluation was to focus on the framework implementation's ability to realize the goals of Semantic Web Services, how easy a Semantic Web Service could be created for the given implementation, and to evaluate the available documentation and tools. The goal of the evaluation was to come up with suggestions for improvements for the framework implementation. The WSMO framework and its WSMX implementation was chosen as subject of the evaluation, based on the evaluation from the first project. The framework was evaluated by implementing a Semantic Web Service from a constructed scenario. The development of this service resulted in positive and negative experiences with the WSMX implementation, experiences that were used in the evaluation. The evaluation focused on WSMX, the available documentation, and the two tools WSMT and WSMO Studio. The results of the evaluation were suggestions for improvements for WSMX, the documentation, and the tools. By making the changes and additions that were suggested, I believe that the development of Semantic Web Services for the WSMX implementation of the WSMO framework could be made easier.
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Buil, Aranda Carlos. "Development of a Semantic Web Solution for Directory Services." Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2005. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9244.
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The motivation for this work is based in a common problem in organizations. The problem is to access and to manage the growing amount of stored data in companies. Companies can take advantage with the utilization of the emerging Semantic Web technology in order to solve this problem. Invenio AS is in a situation where it is necessary to access a directory service in an efficient way and the Semantic Web languages can be used to solve it. In this thesis, a literature study has been done, an investigation about the main ontology languages proposed by World Wide Web Consortium, RDF(S) and OWL with its extension for Web services OWL-S and the ontology language proposed by the International Organization for Standardization, Topic Maps. This literature study can be used like an introduction to these Web ontology languages RDF, OWL (and OWL-S) and Topic Maps. A model of the databases has been extracted and designed in UML. The extracted model has been used to create a common ontology, merging both the initial databases. The ontology that represents the database in the three languages has been analysed. The quality and semantic accuracy of the languages for the Invenio case has been analysed and we have obtained detailed results from this analysis.
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Aslam, Muhammad Ahtisham. "Towards integration of business processes and semantic web services /." Leipzig : Leipziger Informatik Verbund (LIV), 2008. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=016429880&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Maleshkova, Maria. "Towards open services on the Web : a semantic approach." Thesis, Open University, 2015. http://oro.open.ac.uk/42101/.
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The World Wide Web (WWW) has significantly evolved since it was first released as a publicly available service on the Internet, developing from a collection of a few interlinked static pages to a global ubiquitous platform for sharing, searching and browsing dynamic and customisable content, in a variety of different media formats. It plays a major role in the lives of individuals, as a source of information, knowledge and entertainment, as well as in the way business and communication are done within and between companies. This transformation was triggered by the ever-growing number of users and websites, and continues to be supported by current developments such as the SocialWeb, Linked Data, andWeb APIs and Services, which together pave the way for the Web as a dynamic data environment. The work presented in this thesis aims to contribute to a more integrated Web, where services, data and Web content can be seamlessly combined and interlinked, without having to deal with the intricacies of the separate data sources or the specific technology implementations. The vision of Open Services on the Web aims to facilitate the unified use of Web APIs, Web Services and Linked Data sources, so that users can retrieve data without differentiating whether its source is a website, a Web API or even a mashup. However, before this can be achieved, there are a number of problems that need to be addressed. In particular, the integrated and unified handling of services, and especially Web APIs, is very challenging because of the heterogeneous landscape of implementation approaches, underlying technologies and forms of documentation. In particular, in the context of Web APIs, the main limitations are caused by the fact that currently documentation is commonly provided directly in HTML, as part of a webpage, which is not meant for automated machine processing of the service properties, in contrast to XML, for example. This situation is aggravated by the fact that Web APIs are proliferating quite autonomously, without adhering to particular guidelines and specifications. This results in a wide variety of description forms and structures, accompanied by a range of diverse underlying technologies, forcing developers to individually interpret the documentation, and carry out complicated and tedious development work. The result is the implementation of individual custom solutions that are rarely reusable and have very low support for interoperation. We contribute towards achieving the vision Open Services on theWeb by tackling some of these challenges and supporting the wider, integrated and more automated use of Web APIs. In particular, we present a thorough analysis of the current state of Web APIs, giving the results of two Web API surveys. We use the collected data in order to draw conclusions about occurring practices and trends, and common API characteristics. The results provide essential input for acquiring a real-world view onWeb APIs, for identifying key service properties, for determining best practices, for pointing out difficulties and implementation challenges, and for deducing a baseline for the support that any solution approach needs to provide. The so gathered details are used for developing a shared formal model for describing, modelling and annotating Web APIs, which serves as the basis for decreasing the level of manual effort, involved in completing common service tasks, and provides a unifying overlay on top of the heterogeneous API landscape. This shared model - the Core Service Model captures all essential API characteristics, thus providing common grounds for developing support solutions in the context of using Web APIs, but also enables a unified view over traditional Web services and APIs, facilitating their interoperable handing and enabling the reuse of existing Web service approaches and solutions.
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Di, Pietro Ivan. "Process-level selection and composition of semantic web services." Doctoral thesis, Università Politecnica delle Marche, 2010. http://hdl.handle.net/11566/242280.
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Gomadam, Karthik Rajagopal. "Semantics Enriched Service Environments." Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1251246445.
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Lamparter, Steffen. "Policy based contracting in semantic web service markets." Karlsruhe : Univ.-Verl. Karlsruhe, 2007. http://www.uvka.de/univerlag/volltexte/2007/282/.
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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 compositionService 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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Al, Asswad Mohammad Mourhaf. "Semantic information systems engineering : a query-based approach for semi-automatic annotation of web services." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/5441.
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There has been an increasing interest in Semantic Web services (SWS) as a proposed solution to facilitate automatic discovery, composition and deployment of existing syntactic Web services. Successful implementation and wider adoption of SWS by research and industry are, however, profoundly based on the existence of effective and easy to use methods for service semantic description. Unfortunately, Web service semantic annotation is currently performed by manual means. Manual annotation is a difficult, error-prone and time-consuming task and few approaches exist aiming to semi-automate that task. Existing approaches are difficult to use since they require ontology building. Moreover, these approaches employ ineffective matching methods and suffer from the Low Percentage Problem. The latter problem happens when a small number of service elements - in comparison to the total number of elements – are annotated in a given service. This research addresses the Web services annotation problem by developing a semi-automatic annotation approach that allows SWS developers to effectively and easily annotate their syntactic services. The proposed approach does not require application ontologies to model service semantics. Instead, a standard query template is used: This template is filled with data and semantics extracted from WSDL files in order to produce query instances. The input of the annotation approach is the WSDL file of a candidate service and a set of ontologies. The output is an annotated WSDL file. The proposed approach is composed of five phases: (1) Concept extraction; (2) concept filtering and query filling; (3) query execution; (4) results assessment; and (5) SAWSDL annotation. The query execution engine makes use of name-based and structural matching techniques. The name-based matching is carried out by CN-Match which is a novel matching method and tool that is developed and evaluated in this research. The proposed annotation approach is evaluated using a set of existing Web services and ontologies. Precision (P), Recall (R), F-Measure (F) and Percentage of annotated elements are used as evaluation metrics. The evaluation reveals that the proposed approach is effective since - in relation to manual results - accurate and almost complete annotation results are obtained. In addition, high percentage of annotated elements is achieved using the proposed approach because it makes use of effective ontology extension mechanisms.
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Karagoz, Funda. "Application Of Schema Matching Methods To Semantic Web Service Discovery." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607593/index.pdf.
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The Web turns out to be a collection of services that interoperate through the Internet. As the number of services increase, it is getting more and more diffucult for users to find, filter and integrate these services depending on their requirements. Automatic techniques are being developed to fulfill these tasks. The first step toward automatic composition is the discovery of services needed. UDDI which is one of the accepted web standards, provides a registry of web services. However representation capabilities of UDDI are insufficient to search for services on the basis of what they provide. Semantic web initiatives like OWL and OWL-S are promising for locating exact services based on their capabilities. In this thesis, a new semantic service discovery mechanism is implemented based on OWL-S service profiles. The service
profiles of an advertisement and a request are matched based on OWL ontologies describing them. In contrast to previous work on the subject, the ontologies of the advertisement and the request are not assumed to be same. In case they are different, schema matching algorithms are applied. Schema matching algorithms find the mappings between the given schema models. A hybrid combination of semantic, syntactic and structural schema matching algorithms are applied to match ontologies
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Prazeres, Cássio Vinícius Serafim. "Serviços Web Semânticos: da modelagem à composição." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-20052010-162911/.
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A automação de tarefas como descoberta, composição e invocação de Serviços Web é um requisito importante para o sucesso da Web Semântica. Nos casos de insucesso na busca por um serviço, por não existir disponível um serviço completo que atenda plenamente a requisição do usuário, uma possibilidade de contorno é compor o serviço procurado a partir de elementos básicos que atendam parcialmente a requisição inicial e que se completem. A composição de Serviços Web pode ser realizada de forma manual ou de forma automática. Na composição manual, o desenvolvedor de Serviços Web pode tirar proveito da sua expertise sobre os serviços envolvidos na composição e sobre o resultado que se deseja alcançar. Esta tese aborda problemas e apresenta contribuições relacionadas ao processo de composição automática de Serviços Web. A composição automática de Serviços Web requer que os serviços sejam descritos e publicados de forma a modelar o conhecimento (semântica explícita) que o desenvolvedor utiliza para realizar a composição manual. A descoberta automática baseada nas descrições semânticas do serviço é também um passo crucial na direção da composição automática, pois é um estágio anterior necessário para a seleção dos serviços candidatos à composição. Trabalhos da área de pesquisa em Serviços Web Semânticos exploram a utilização dos padrões da Web Semântica para enriquecer, com semântica explícita, a descrição dos Serviços Web. O problema da composição automática de Serviços Web é tratado neste trabalho por meio de três linhas de investigação: modelagem dos Serviços Web Semânticos; descoberta automática de Serviços Web Semânticos; e composição automática de Serviços Web Semânticos. As contribuições desta tese incluem: a plataforma RALOWS para modelagem de aplicações Web como Serviços Web Semânticos, tendo como estudo de caso aplicações para realização de experimentos remotos; um algoritmo para descoberta automática de Serviços Web Semânticos; uma proposta baseada em grafos e caminhos de custo mínimo para prover composição automática de Serviços Web Semânticos; uma infra-estrutura e ferramentas de apoio à descrição, publicação, descoberta e composição de Serviços Web SemânticosThe automation of the discovery, composition and invocation of Web Services is an important step to the success of the Semantic Web. If no single Web Service satisfies the functionality required by one user, an alternative is to combine existing services that solve parts of the problem in order to reach a complete solution. Web Services composition can be achieved manually or automatically. When composing services manually, Web Service developers can take advantage of their expertise and knowledge about the composition services and the target service. This thesis addresses issues and presents contributions related to the process of automating Web Services composition. The automatic composition of Web services requires the description and publication of the services in order to model the necessary knowledge (explicit semantics) that the developer uses to perform the manual composition. The automatic Web Service discovery is a crucial step toward the automatic composition, because it is a previous stage necessary to the selection of composition service candidates. Semantic Web Services researches explore the use of the Semantic Web technologies to enrich the Web Services descriptions with explicit semantics. Three main lines of investigation are adopted in this thesis to explore the process of automatic composition of Web Services. They are the following: Semantic Web Services modeling; automatic discovery of Semantic Web Services; and automatic composition of Semantic Web Services. The main contributions of this thesis include: the RALOWS platform for modeling Web applications as Semantic Web Services; an algorithm for the automatic discovery of Semantic Web Services; a graph-based approach to the automatic composition of Semantic Web Services; and an infrastructure and tools to support the Semantic Web Services description, publishing, discovery and composition
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Cheong, Io Peng. "The semantic Web services framework for automating SOA-based systems." Thesis, University of Macau, 2006. http://umaclib3.umac.mo/record=b1446083.
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Okat, Caglar. "Using Semantic Web Services For Data Integration In Banking Domain." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611782/index.pdf.
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A semantic model oriented transformation mechanism is developed for the centralization of intra-enterprise data integration. Such a mechanism is especially crucial in the banking domain which is selected in this study. A new domain ontology is constructed to provide basis for annotations. A bottom-up approach is preferred for semantic annotations to utilize existing web service definitions. Transformations between syntactic web service XML responses and semantic model concepts are defined in transformation files. Transformation files are stored and executed in a separate central transformation repository to enhance abstraction and reusability. An RDF-Store is implemented to store transformed RDF data. Inference power of semantic model is exposed by executing semantic queries in the RDF-Store.
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Yang, Xu. "Multi-channel Mobile Access to Web Services." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/30270.
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To support wireless-oriented services, a new generation of Web services called Mobile services (M-services) has emerged. M-services provide mobile users access to services through wireless networks. One of the important issues in M-service environment is how to discover and access M-services efficiently. In this dissertation, we propose time and power efficient access methods for M-services. We focus on methods for accessing broadcast based M-services from multiple wireless channels. We first discuss efficient access methods in data-oriented wireless broadcast systems. We then discuss how to extend current wireless broadcast systems to support simple M-services. We present a novel infrastructure that provides a multi-channel broadcast framework for mobile users to effectively discover and access composite M-services. Multi-channel algorithms are proposed for efficiently accessing composite
services. We define a few semantics that have impact on access efficiency in the proposed infrastructure. We discuss semantic access to composite services. Broadcast channel organizations suitable for discovering and accessing composite services are proposed. We also derive analytical models for these channel organizations. To provide practical study for the proposed infrastructure and access methods, a testbed is developed for simulating accessing M-services in a broadcast-based environment.
Extensive experiments have been conducted to study the proposed access methods and broadcast channel organizations. The experimental results are presented and discussed.Ph. D.
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Tizzo, Neil Paiva. "Composição automática de serviços web semânticos : uma abordagem com times assíncronos e operadores genéticos." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260393.
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Orientadores: Eleri Cardozo, Juan Manuel Adán CoelloTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: A automação da composição de serviços Web é, na visão do autor, um dos problemas mais importantes da área de serviços Web. Além de outras características, destaca-se que somente a composição automática é capaz de lidar com ambientes mutáveis onde os serviços são permanentemente inseridos, removidos e modificados. Os métodos existentes para realizar a composição automática de serviços apresentam várias limitações. Alguns tratam de um número muito restrito de fluxos de controles e outros não consideram a marcação semântica dos serviços. Em adição, em muitos casos não há avaliações quantitativas do desempenho dos métodos. Desta forma, o objetivo desta tese é propor um método para realizar a composição automática de serviços Web semânticos que considera os cinco tipos básico de fluxo de controle identificados pela Workflow Management Coalition, a saber: sequencial, separação paralela, sincronização, escolha-exclusiva e união simples; bem como para o fluxo de controle em laço, considerado um fluxo do tipo estrutural. As regras que descrevem a composição entre os serviços são híbridas, baseadas em semântica e em técnicas de recuperação de informação. Os serviços são descritos em OWL-S, uma ontologia descrita em OWL que permite descrever semanticamente os atributos IOPE (parâmetros de entrada, de saída, pré-requisitos e efeitos) de um serviço, mas somente os parâmetros de entrada e saída foram levados em consideração neste trabalho. Para validar a abordagem foi implementado um protótipo que utilizou times assíncronos (A-Teams) com agentes baseados em algoritmos genéticos para realizar a composição segundo os padrões de fluxo sequencial, paralelo e sincronização. A avaliação experimental do algoritmo de composição foi realizada utilizando uma coleção de serviços Web semânticos pública composta de mais de 1000 descrições de serviços. As avaliações de desempenho, em vários cenários típicos, medidas em relação ao tempo de resposta médio e à quantidade de vezes em que a função de avaliação (função fitness) é calculada são igualmente apresentadas. Para os casos mais simples de composição, o algoritmo conseguiu reduzir o tempo de resposta em relação a uma busca cega em aproximadamente 97%. Esta redução aumenta à medida que a complexidade da composição também aumenta
Abstract: The automation of the composition of Web services is, in the view of the author, one of the most important problems in the area of Web services. Beyond other characteristics, only the automatic composition can deal with a changing environment where the services are permanently inserted, removed, and modified. Existing methods performing the automatic service composition have several limitations. Some deal with a very limited number of control flow patterns, while others do not consider the semantic markup of services. In addition, in many cases there is no quantitative evaluation of the method's performance. In such a way, the objective of this thesis is to propose a method to perform the automatic composition of semantic Web services considering the five basic types of control flow identified by the Workflow Management Coalition, namely: sequential, parallel split, synchronization, exclusive choice and simple merge; and for loop control flow, classified as a structural control flow pattern. The rules that describe the composition of the service are hybrid: based in semantics and in information retrieval techniques. Services are described in OWL-S, an ontology described in OWL that allows the semantically description of the IOPE attributes (input, output, prerequisite and effect) of a service, but only the input and output parameters were taken into consideration in this work. A prototype was implemented to validate the proposed rules. An asynchronous Team (A-Team) algorithm with genetic agents was used to carry out the composition according to the sequential, parallel and synchronization control flows. The experimental evaluation of the composition algorithm employed a public collection of semantic Web services composed of more than 1000 descriptions of services. An experimental performance evaluation showed that, for simple composition cases, the algorithm reduced the average response time in approximately 97%, when compared to blind search. This reduction increases as the composition complexity increases
Doutorado
Engenharia de Computação
Doutor em Engenharia Elétrica
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Utku, Selma. "Web Service Testing For Domain Specific Web Service Discovery Framework." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614083/index.pdf.
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The reliability of web services is important for both users and other service providers, with which they are in interaction. Thus, to guarantee reliability of the web services that are invoked and integrated at runtime, automatic testing of web services is needed.
In web service testing, different test cases for web services are generated. The most important issue is to generate the most appropriate value for input parameters of web services at runtime. In this thesis, we developed a method for automatic web service testing that uses semantics dependency-based and data mutation-based techniques to analyze web services and generate different test cases. Thus, we both check whether the services function correctly by generating appropriate input values from different data sources and check robustness of web services by generating random and error-prone data inputs. With respect to the behaviors of web services, the test values are calculated and saved to the database for each web service.
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Kirci, Esra. "Automatic Composition Of Semantic Web Services With The Abductive Event Calculus." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609949/index.pdf.
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In today's world, composite web services are widely used in service oriented computing, web mashups and B2B Applications etc. Most of these services are composed manually. However, the complexity of manually composing web services increase exponentially with the increase in the number of available web services, the need for dynamically created/updated/discovered services and the necessity for higher amount of data bindings and type mappings in longer compositions. Therefore, current highly manual web service composition techniques are far from being the answer to web service composition problem. Automatic web service composition methods are recent research efforts to tackle the issues with manual techniques. Broadly, these methods fall into two groups: (i) workflow based methods and (ii) methods using AI planning. This thesis investigates the application of AI planning techniques to the web service composition problem and in particular, it proposes the use of the abductive event calculus in this domain. Web service compositions are defined as templates using OWL-S ("
OWL for Services"
). These generic composition definitions are converted to Prolog language as axioms for the abductive event calculus planner and solutions found by the planner constitute the specific result plans for the generic composition plan. In this thesis it is shown that abductive planning capabilities of the event calculus can be used to generate the web service composition plans that realize the generic procedure.
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Yu, Liyang. "An Indexation and Discovery Architecture for Semantic Web Services and its Application in Bioinformatics." Digital Archive @ GSU, 2006. http://digitalarchive.gsu.edu/cs_theses/20.
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Recently much research effort has been devoted to the discovery of relevant Web services. It is widely recognized that adding semantics to service description is the solution to this challenge. Web services with explicit semantic annotation are called Semantic Web Services (SWS). This research proposes an indexation and discovery architecture for SWS, together with a prototype application in the area of bioinformatics. In this approach, a SWS repository is created and maintained by crawling both ontology-oriented UDDI registries and Web sites that hosting SWS. For a given service request, the proposed system invokes the matching algorithm and a candidate set is returned with different degree of matching considered. This approach can add more flexibility to the current industry standards by offering more choices to both the service requesters and publishers. Also, the prototype developed in this research shows the value can be added by using SWS in application areas such as bioinformatics.
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Chabeb, Yassin. "Contributions à la description et la découverte de services web sémantiques." Phd thesis, Institut National des Télécommunications, 2011. http://tel.archives-ouvertes.fr/tel-00843597.
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Les travaux de recherche menés autour de la description de services Web utilisent de plus en plus des modèles sémantiques pour fournir une représentation interprétable automatiquement. Toutefois, nous avons décelé des lacunes dans les approches sémantiques actuelles qui engendrent ambiguïté et non pertinence au niveau de l'appariement et de la découverte de services Web. Pour remédier à ces lacunes nous proposons des contributions à la description et à la découverte de services Web sémantiques. En ce qui concerne la description de services, nous avons défini un langage basé sur une recommandation W3C. En plus d'une annotation métier sémantique des éléments d'un service, notre principale contribution à la description sémantique consiste à spécifier la nature de ces annotations en utilisant une ontologie technique que nous avons définie. Cette ontologie met en relation plusieurs concepts sémantiques de services Web que nous avons identifiés dans des approches existantes et intègrera d'autres concepts qu'on définira ultérieurement sans pour autant modifier notre langage de description ou nos techniques d'appariement associées. Nous avons également défini un algorithme d'appariement entre une requête de service et les descriptions des services publiés. Cet algorithme se base sur un appariement entre éléments d'une requête et un service publié et trois techniques d'agrégation des résultats d'appariements élémentaires. L'algorithme tire avantage de la description sémantique que nous avons définie. Il a été mis en œuvre dans un annuaire de services Web sémantiques et a été également comparé aux algorithmes de référence. Les expérimentations montrent clairement l'efficacité de notre approche en termes de temps de réponse et de précision
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Okutan, Cagla. "A Monolithic Approach To Automated Composition Of Semantic Web Services With The Event Calculus." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611082/index.pdf.
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In this thesis, a web service composition and execution framework is presented for semantically
annotated web services. A monolithic approach to automated web service composition
and execution problem is chosen, which provides some benefits by separating the composition
and execution phases. An AI planning method using a logical formalism called Event
Calculus is chosen for the composition phase. This formalism allows one to generate a narrative
of actions and temporal orderings using abductive planning techniques given a goal.
Functional properties of services, namely input/output/precondition/effects(IOPE) are taken
into consideration in the composition phase and non-functional properties, namely quality of
service (QoS) parameters are used in selecting the most appropriate solution to be executed.
The repository of OWL-S semanticWeb services are translated to Event Calculus axioms and
the resulting plans found by the Abductive Event Calculus Planner are converted to graphs.
These graphs can be sorted according to a score calculated using the defined quality of service
parameters of the atomic services in the composition to determine the optimal solution. The
selected graph is converted to an OWL-S file which is executed consequently.
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Patnaik, Sambit. "A framework for improving tractability in software development." Birmingham, Ala. : University of Alabama at Birmingham, 2006. http://www.mhsl.uab.edu/dt/2006m/patnaik.pdf.
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Klein, Michael. "Automatisierung dienstorientierten Rechnens durch semantische Dienstbeschreibungen." Karlsruhe : Univ.-Verl. Karlsruhe, 2006. http://deposit.d-nb.de/cgi-bin/dokserv?idn=980335396.
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Al, Muhammed Muhammed Jassem. "Ontology Aware Software Service Agents: Meeting Ordinary User Needs on the Semantic Web." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2078.pdf.
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Sun, Z. "Using ontology and semantic web services to support modeling in systems biology." Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/18604/.
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This thesis addresses the problem of collaboration among experimental biologists and modelers in the study of systems biology by using ontology and Semantic Web Services techniques. Modeling in systems biology is concerned with using experimental information and mathematical methods to build quantitative models across different biological scales. This requires interoperation among various knowledge sources and services. Ontology and Semantic Web Services potentially provide an infrastructure to meet this requirement. In our study, we propose an ontology-centered framework within the Semantic Web infrastructure that aims at standardizing various areas of knowledge involved in the biological modeling processes. In this framework, first we specify an ontology-based meta-model for building biological models. This meta-model supports using shared biological ontologies to annotate biological entities in the models, allows semantic queries and automatic discoveries, enables easy model reuse and composition, and serves as a basis to embed external knowledge. We also develop means of transforming biological data sources and data analysis methods into Web Services. These Web Services can then be composed together to perform parameterization in biological modeling. The knowledge of decision-making and workflow of parameterization processes are then recorded by the semantic descriptions of these Web Services, and embedded in model instances built on our proposed meta-model. We use three cases of biological modeling to evaluate our framework. By examining our ontology-centered framework in practice, we conclude that by using ontology to represent biological models and using Semantic Web Services to standardize knowledge components in modeling processes, greater capabilities of knowledge sharing, reuse and collaboration can be achieved. We also conclude that ontology-based biological models with formal semantics are essential to standardize knowledge in compliance with the Semantic Web vision.
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Nakamura, Luis Hideo Vasconcelos. "Utilização de web semântica para seleção de informações de web services no registro UDDI uma abordagem com qualidade de serviço." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-30032012-134557/.
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Este projeto de mestrado aborda a utilização de recursos daWeb Semântica na seleção de informações sobre Web Services no registro UDDI (Universal Description, Discovery, and Integration). Esse registro possui a limitação de apenas armazenar informações funcionais de Web Services. As informações não funcionais que incluem as informações de qualidade de serviço (QoS - Quality of Service) não são contempladas e dessa forma dificulta a escolha do melhor serviço pelos clientes. Neste projeto, a representação da base de conhecimento com informações sobre os provedores, clientes, acordos, serviços e a qualidade dos serviços prestados foi feita por meio de uma ontologia. Essa ontologia é utilizada pelo módulo UDOnt-Q (Universal Discovery with Ontology and QoS) que foi projetado para servir de plataforma para algoritmos de busca e composição de serviços com qualidade. Embora a utilização de semântica possa ser empregada para a composição e automatização de serviços, o foco deste trabalho é a garantia de qualidade de serviço em Web Services. Os algoritmos desenvolvidos empregam recursos da Web Semântica para classificar e selecionar os Web Services adequados de acordo com as informações de qualidade que estão armazenados na ontologia. O módulo e os algoritmos foram submetidos a avaliações de desempenho que revelaram problemas de desempenho com relação a abordagem adotada durante o processo de inferência da ontologia. Tal processo é utilizado para a classificação das informações dos elementos presentes na ontologia. Contudo, uma vez que as informações foram inferidas, o processo de busca e seleção de serviços comprovou a viabilidade de utilização do módulo e de um dos seus algoritmos de seleçãoThis master project addresses the use of Semantic Web resources in the selection of information about Web Services in UDDI registry (Universal Description, Discovery, and Integration). This registry has the limitation of only storing functional information of Web Services. The nonfunctional information that includes the quality of service information (QoS - Quality of Service) is not covered and thus it is complicate to choose the best service for customers. In this project, the representation of the knowledge base with information about the providers, customers, agreements, services and quality of services has been made through an ontology. This ontology is used by the module UDOnt-Q (Universal Discovery with Ontology and QoS) that was designed to serve as a platform for search algorithms and composition of services with quality. Although the use of semantics can be adopted for the composition and automation of services, the focus of this work is to guarantee quality of service in Web Services. The developed algorithms employ SemanticWeb resources to classify and select the appropriate Web Services according to the quality information that is stored in the ontology. The module and the algorithms have been subjected to performance evaluations that revealed performance problems in relation to the approach taken during the ontology inference process. This process is used for classification of information of the elements present in the ontology. However, since the information was inferred, the process of search and selection services proved the viability of using the module and one of its selection algorithms
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Lira, Hermano Albuquerque. "Semantic data services : uma abordagem para acesso e manipulação de dados interligados." Universidade de Fortaleza, 2014. http://dspace.unifor.br/handle/tede/93439.
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Previous issue date: 2014-12-16Linked Data is a kind of data that is available on the Web and adopt the Resource Description Framework (RDF) model to represent their structures. Linked Data also adopts the Web Ontology Language (OWL) to assign a formal semantics to these structures. Often such data can be accessed by Web Services, such as the SPARQL Services, the Linked Data Services (LIDS) and Linked Data Platform (LDP). However, not all of these approaches have support to writing, what makes it impossible to update the databases in these services. Even in the approaches that support writing, the data integrity checking mechanisms are limited, or nonexistent. In this work, we propose the Semantic Data Services (SDS), an approach to building RESTful Data Services with writeable Linked Data support and integrity constraint check support. This approach takes the RESTful Semantic Interface (SERIN) specification for building service descriptors. These interfaces define what type of data is provided and what operations are allowed on SDS services. A key differentiator of SDS approach is that while other approaches adopt the Open World Assumption (OWA), the SDS adopts the Local Closed World Assumption (LCWA). For supporting LCWA, the SDS extended SERIN specification, adding a new set of annotations that define integrity constraint rules on data. A typical characteristic of OWA is that the domain of data is always considered incomplete. This implies that the databases of services based on that assumption does not have a well-defined schema. This characteristic makes it difficult to implement a data integrity constraint mechanism for such services. On the other hand, in the SDS approach, the new annotations added in SERIN specification act as markers that tell to SDS service what types of data should be interpreted according to the LCWA. Our approach allow defining which data may, or may not, be inserted into the base. It is possible to identify incomplete or inconsistent data, according to integrity rules defined via these new annotations. In general, SDS approach helps to establish the domain of knowledge in a RDF graph store. Keywords: Data Services; Linked Data; SERIN; Integrity Constraint Check.
Dados interligados (Linked Data) são dados disponibilizados na Web que adotam o modelo RDF (Resource Description Framework) para representar suas estruturas e a linguagem OWL (Web Ontology Language) para atribuir uma semântica formal a essas estruturas. Frequentemente tais dados podem ser acessados por serviços Web, como por exemplo os serviços SPARQL, os serviços de dados interligados (LInked Data Services - LIDS) e os serviços LDP (Linked Data Platform). Contudo, nem todas essas abordagens possuem suporte à escrita. O que impossibilita a atualização das bases de dados desses serviços por seus clientes. Mesmo nas abordagens com suporte à escrita, são limitados ou inexistentes os mecanismos de verificação de integridade de dados. Neste trabalho, propomos os serviços de dados semânticos (Semantic Data Services - SDS), uma abordagem para construção de serviços RESTful provedores de dados interligados com suporte à escrita e a verificação de integridade. Essa abordagem adota a especificação SERIN (Semantic RESTful Interface) para a construção de interfaces descritoras de serviços. Tais interfaces definem que tipos de dados são providos e quais operações permitidas nos serviços SDS. Um importante diferencial da abordagem SDS é que enquanto as outras abordagens adotam a suposição de mundo aberto, o SDS adota a suposição de mundo fechado localmente. Para o SDS suportar essa suposição, estendeu-se a especificação SERIN, adicionando um conjunto de anotações que definem regras de restrição de integridade sobre os dados. Uma característica típica da suposição de mundo aberto é que o domínio de conhecimento dos dados é sempre considerado incompleto. Isso implica que as bases de dados de serviços baseados nessa suposição não possuem um esquema bem definido. Essa característica dificulta a implementação de mecanismos de verificação de integridade de dados para tais serviços. Por outro lado, na abordagem SDS as novas anotações adicionadas à especificação SERIN atuam como marcadores que informam ao serviço SDS que tipos de dados devem ser interpretados segundo a suposição de mundo fechado localmente. Isso permite definir formalmente que dados podem, ou não, ser inseridos na base. É possível identificar dados incompletos ou inconsistentes de acordo com regras de integridade definidas via essas novas anotações. De maneira geral, a abordagem SDS contribui para delimitar com precisão o domínio de conhecimento de uma base de dados interligados. Palavras-chave: Serviços de acesso a dados; Dados interligados; interface SERIN; Verificação de restrições de integridade.
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Gupta, Chaitali. "Web services query matchmaking with automated knowledge acquisition." Diss., Online access via UMI:, 2007.
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Santos, Pedro Bispo da Silva. "Aperfeiçoamento de métricas de similaridade semântica entre serviços web." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/56842.
Full textAbstract:
O presente trabalho apresenta uma abordagem aperfeiçoada para medir similaridade entre Serviços Web Semânticos através de um algoritmo baseado em ontologia. O trabalho se trata de um aperfeiçoamento por pegar como base o algoritmo de Liu (LIU et al., 2009) e nele fazer uma pequena mudança que resulta em melhorias significativas em certos cenários. Este algoritmo utiliza informação das categorias ESPE (Entradas, Saídas, Pré-condições, Efeitos), procurando por informações presentes nessas categorias, analisando como os conceitos estão relacionados na taxonomia da ontologia. A escolha do trabalho de Liu ocorreu devido a experimentos realizados em trabalhos anteriores ao desta dissertação (MAAMAR et al., 2011)(MAAMAR et al., 2011). Nesses experimentos, foi constatado que o algoritmo não antigia um desempenho satisfatório, foi então que se levantou uma hipótese de aperfeiçoamento deste algoritmo. Experimentos realizados utilizando um conjunto de dados contendo 1083 Serviços Web Semânticos em OWL-S mostram que essa abordagem aperfeiçoada aumenta a precisão do algoritmo, diminuindo desta forma o número de falsos positivos recuperados nos resultados, mantendo uma boa revocação. Nestes experimentos, foram implementados o algoritmo original de Liu e a versão modificada apresentada nesta dissertação. Além disso, este trabalho apresenta quais parâmetros utilizar para configurar o algoritmo e atingir melhor precisão, revocação e f-measure.The current work presents an improved approach for an ontology-based semantic web service matchmaking assessment algorithm. This work is based on Liu’s algorithm LIU et al. (2009) providing a small change which results in a significant enhancement at some scenarios. The algorithm uses information from IOPE (Inputs, Outputs, Preconditions, Effects) categories, searching for information about the concepts located in these categories, analyzing how they are related in an ontology taxonomy. Liu’s work was chosen due to experiments that were done in works previous to this dissertation (MAAMAR et al., 2011)(MAAMAR et al., 2011). During those experiments, it was realized that Liu’s algorithm did not achieve good results. Then, an hypothesis was raised for improving this algorithm. Experiments performed using a data set containing 1083 OWL-S semantic web services show that the improved approach increases the algorithm precision, diminishing the number of false positives in the retrieved results, and still having a good recall. For doing these experiments, Liu’s algorithm and this dissertation version of it were implemented. Furthermore, this work presents the parameters that were used to achieve better precision, recall and f-measure.