Uma abordagem automática para descoberta e composição de serviços web semânticos

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Ciência da Computação, Florianópolis, 2012A adição de semântica à descrição de Serviços Web visa permitir a automação dos processos de descoberta e composição de serviços. Para que isso seja possível, é necessário que sejam desenvolvidas ferramentas que façam com que esses processos sejam realizados dinamicamente, sem a necessidade de intervenção humana. Diversos trabalhos na área de Web Semântica têm explorado a descoberta e a composição de Serviços Web através da descrição semântica das suas funcionalidades. Este trabalho apresenta uma abordagem para a descoberta e a composição de Serviços Web Semânticos de forma automática. Mediante o envio de uma requisição com a descrição das funcionalidades de um serviço, a abordagem proposta possibilita que composições sejam estabelecidas quando um único Serviço Web não é suficiente para atender as necessidades dos usuários. Por meio de anotações semânticas baseadas em SAWSDL (Semantic Annotations for WSDL), a abordagem proposta realiza o matching semântico das funcionalidades dos serviços web disponíveis em repositórios de serviços com as informações enviadas na requisição e constrói um grafo de composições. No final da construção do grafo, um algoritmo analisa se dois ou mais caminhos levam à mesma informação desejada pelo usuário. Caso isso aconteça, uma função é aplicada para cada caminho, a fim de selecionar aquele com o menor grau de divergência semântica. A proposta da abordagem apresentada é criar composições de serviços web em tempo de requisição de modo que sejam capazes de combinar serviços pré-existentes para criar um novo serviço, tirando proveito das funcionalidades oferecidas por cada um e combinando-as a fim de oferecer funcionalidades ainda mais complexas e até inexistentes. Dessa forma, a abordagem torna o processo de busca e composição de serviços web capaz de informar não apenas serviços individuais, mas também composições de serviços. Como contribuições deste trabalho citam-se: um algoritmo para a seleção de composições baseado na qualidade semântica das mesmas e um protótipo em conjunto com uma infraestrutura para a descoberta e a composição de serviços web.Abstract : The addition of semantic to web services description allows the automation of the discovery and composition process. However, tools must be developed to allow these processes be performed dynamically without human intervention. Several studies in the area of the Semantic Web have explored the discovery and composition of Web Services through semantic description of its functionality. This work presents an approach for automatic discovery and composition of semantic web services. By sending a request with the description of a service functionality, the proposed approach enables compositions to be established when a single web service is not sufficient to meet the user needs. Through semantic annotations based on SAWSDL (Semantic Annotations for WSDL), the proposed approach performs the semantic matching of Web services capabilities available in services repositories with the information sent in the request and builds a composition graph. At the end of the construction of the graph, an algorithm analyzes if two or more paths lead to the same information desired by the user. If this happens, a function is applied to each path in order to select the one with the lowest semantic mismatch degree. The purpose of the presented approach is to create compositions of web services at request time so that they are able to combine pre-existing services to create a new service, taking advantage of the functionality offered by each and combining them to provide functionality yet more complex and even non-existent. Thus, the approach makes the process of discovery and composition of web services return not only individual services, but also compositions of services. The main contributions of this work are: an algorithm for selection of compositions based on its semantics quality, a prototype and an infrastructure for discovery and composition of web services

Combining Configuration and Query Rewriting for Web Service Composition

International audienceIn this paper, we investigate the combination of configuration and query rewriting for semantic Web service composition.Given a user query and a set of service descriptions, we rely on query rewriting to find services that implement the functionalities expressed in the user query (discovery stage). Then, we use configuration to capture dependencies between services, and to generate a set of composed Web services described as a directed acyclic graph, while maintaining validity with respect to business rules (orchestration stage).Finally, we propose a semantic ranking algorithm to rank results according to user preferences (classification stage).The techniques used in our approach take into account the semantics of concepts utilized to describe the elements (services, business rules, query and user preferences) involved in the composition process.We provide a formal approach and its implementation, together with experiments on Web services from different application domains

Designing a Framework for Exchanging Partial Sets of BIM Information on a Cloud-Based Service

The rationale behind this research study was based on the recognised difficulty of exchanging data at element or object level due to the inefficiencies of compatible hardware and software. Interoperability depicts the need to pass data between applications, allowing multiple types of experts and applications to contribute to the work at hand. The only way that software file exchanges between two applications can produce consistent data and change management results for large projects is through a building model repository. The overall aim of this thesis was to design and develop an integrated process that would advance key decisions at an early design stage through faster information exchanges during collaborative work. In the construction industry, Building Information Modeling is the most integrated shared model between all disciplines. It is based on a manufacturing-like process where standardised deliverables are used throughout the life cycle with effective collaboration as its main driving force. However, the dilemma is how to share these properties of BIM applications on one single platform asynchronously. Cloud Computing is a centralized heterogeneous network that enables different applications to be connected to each other. The methodology used in the research was based on triangulation of data which incorporated many techniques featuring a mixture of both quantitative and qualitative analysis. The results identified the need to re-engineer Simplified Markup Language, in order to exchange partial data sets of intelligent object architecture on an integrated platform. The designed and tested prototype produced findings that enhanced project decisions at a relatively early design stage, improved communication and collaboration techniques and cross disciple co-ordination