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.

Web services are often used for search computing where data is retrieved from servers providing information of different kinds. Such data providing web services return a set of objects for a given set of parameters without any side effects. There is need to enable general and scalable search capabilities of data from data providing web services, which is the topic of this Thesis. The Web Service MEDiator (WSMED) system automatically provides relational views of any data providing web service operations by reading the WSDL documents describing them. These views can be queried with SQL. Without any knowledge of the costs of executing specific web service operations the WSMED query processor automatically and adaptively finds an optimized parallel execution plan calling queried data providing web services. For scalable execution of queries to data providing web services, an algebra operator PAP adaptively parallelizes calls in execution plans to web service operations until no significant performance improvement is measured, based on monitoring the flow from web service operations without any cost knowledge or extensive memory usage. To comply with the Everything as a Service (XaaS) paradigm WSMED itself is implemented as a web service that provides web service operations to query and combine data from data providing web services. A web based demonstration of the WSMED web service provides general SQL queries to any data providing web service operations from a browser. WSMED assumes that all queried data sources are available as web services. To make any data providing system into a data providing web service WSMED includes a subsystem, the web service generator, which generates and deploys the web service operations to access a data source. The WSMED web service itself is generated by the web service generator. / eSSENCE

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

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Climate influences a large variety of human activities and the real-time access to climatic data aims for providing information that are fundamental in several human activities, mainly for agriculture. Nowadays there are few weather stations operating, which causes a lack of information at worldwide level, in different regions. Keeping in mind that the state of Rio Grande do Sul has a large part of its economy based on agriculture, as well as the climatological information's relevance, this study aims at developing a web system for numerical estimate of meteorological data in the RS's state, based on the automatical and superficial weather stations from the National Institute of Meteorology (INMET), in order to make the data available to the regions where there are no stations. The inverse distance weighting was used as an interpolation model, applying the exponents from zero (0) to five (5) and, later, comparing them through the coefficients of correlation, regression and the performance index. It was made use of programming languages as PHP, HTML and JavaScript to develop the web system, with support for MySQL database. The programs used were Macromedia Dreamweaver 8.0 and HeidSQL; the first was used for web programming whereas the second was used to manage the database. Among the nine variables that was analysed, just four of them showed a great performance. They are: temperature, relative humidity, atmospheric pressure and dew points. The interpolation model with the exponent five (5) has shown the best performance regarding to the four variables. After defining the best method, it was created a MySQL database called SWIM (Meteorological Interpolation's Web System) and through it the web system was developed, which has offered quickness, security and reliability to the application. / O clima influencia as mais diversas atividades humanas e o acesso aos dados climatológicos em tempo real, visa o fornecimento de informações que são fundamentais, principalmente para a agricultura. Atualmente existem poucas estações meteorológicas instaladas o que gera carência de informações, em âmbito mundial, para diversas regiões. Tendo em vista que o Estado do Rio Grande do Sul possui grande parte de sua economia baseada na agricultura e também a relevância das informações climatológicas, o presente trabalho teve como objetivo desenvolver um sistema web de estimativa numérica de dados meteorológicos para o Estado, com base nas estações meteorológicas automáticas de superfície, do Instituto Nacional de Meteorologia (INMET), com o intuito de dispor os dados para as regiões as quais não possuem estações. Como modelo interpolador foi utilizado o inverso da potência da distância, aplicando os expoentes de 0 a 5 e, posteriormente comparando-os através dos coeficientes de correlação, regressão e índice de desempenho. Para a realização do sistema web foram utilizadas as linguagens de programação PHP, HTML e javascript, com suporte ao banco de dados MYSQL. Utilizou-se os programas Macromedia Dreamweaver 8.0 para a programação web e HeidiSQL para gerenciar o banco de dados. Dentre as nove variáveis analisadas, apenas quatro apresentaram ótimo desempenho, sendo elas: temperatura, umidade relativa do ar, pressão atmosférica e ponto de orvalhos. O modelo de interpolação com expoente 5 foi o que apresentou melhor desempenho para as quatro variáveis. Após definição do melhor método, criou-se o banco de dados SWIM (Sistema Web de Interpolação Meteorológica) em MySQL e desenvolveu-se o sistema web, o qual ofereceu rapidez, segurança e confiabilidade para a aplicação.

ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / The development and analysis cloud is a rapid development system being designed to support the Air Force Research Lab (AFRL) Simulation & Technology Assessment Branch. The purpose is to isolate research, development, test, and evaluation of unique software within a Zone D enclave [1] to allow researchers and analysts to develop and test software free of the many IT requirements that hamper development and without risk of contaminating the overall Air Force network. The cloud system is being designed so researchers and analysts will utilize Software as a Service (SaaS) models. Such a model makes it transparent to users such things as where the software originates and any licensing concerns. Utilities, tools, and other enhancing software that users need are published and using them frees the developer to focus on their specific development efforts versus tertiary development modules.

Usage of cloud-based storage systems gained a lot of prominence in fast few years. Every day millions of files are uploaded and downloaded from cloud storage. This data that cannot be handled by traditional databases and this is considered to be Big Data. New powerful platforms have been developed to store and organize big and unstructured data. These platforms are called Big Data systems. Some of the most popular big data platform are Mongo, Hadoop, and Cassandra. In this, we used Cassandra database management system because it is an open source platform that is developed in java. Cassandra has a masterless ring architecture. The data is replicated among all the nodes for fault tolerance. Unlike MySQL, Cassandra uses per-column basis technique to store data. Cassandra is a NoSQL database system, which can handle unstructured data. Most of Cassandra parameters are scalable and are easy to configure. Amazon provides cloud computing platform that helps a user to perform heavy computing tasks over remote hardware systems. This cloud computing platform is known as Amazon Web Services. AWS services also include database deployment and network management services, that have a non-complex user experience. In this document, a detailed explanation on Cassandra database deployment on AWS platform is explained followed by Cassandra performance tuning.    In this study impact on read and write performance with change Cassandra parameters when deployed on Elastic Cloud Computing platform are investigated. The performance evaluation of a three node Cassandra cluster is done. With the knowledge of configuration parameters a three node, Cassandra database is performance tuned and a draft model is proposed.             A cloud environment suitable for the experiment is created on AWS. A three node Cassandra database management system is deployed in cloud environment created. The performance of this three node architecture is evaluated and is tested with different configuration parameters. The configuration parameters are selected based on the Cassandra metrics behavior with the change in parameters. Selected parameters are changed and the performance difference is observed and analyzed. Using this analysis, a draft model is developed after performance tuning selected parameters. This draft model is tested with different workloads and compared with default Cassandra model. The change in the key cache memory and memTable parameters showed improvement in performance metrics. With increases of key cache size and save time period, read performance improved. This also showed effect on system metrics like increasing CPU load and disk through put, decreasing operation time and The change in memTable parameters showed the effect on write performance and disk space utilization. With increase in threshold value of memTable flush writer, disk through put increased and operation time decreased. The draft derived from performance evaluation has better write and read performance.

A velocidade das mudanças e a necessidade de informações disponíveis em vários meios têm feito com que os sistemas atuais se integrem cada vez mais. Neste cenário, arquiteturas orientadas a serviços e Web Services ganham evidência. Por utilizarem padrões já bem difundidos, por exemplo XML (extended markup language), Web Services se destacam pela interoperabilidade e dinamismo, disponibilizados através da Internet e utilizado em ambientes heterogêneos. Contudo, isso afeta significativamente atributos não funcionais, por exemplo, confiabilidade, disponibilidade, entre outros. Para Web Services, além de todos os problemas existentes no paradigma de programação distribuída, temos ainda o problema de que erros em um determinado serviço não devem ser propagados para os demais. Dentre as diversas formas de se contornar o problema, existe a definição de padrões transacionais que visam delinear regras específicas para a comunicação entre os serviços. O objetivo do trabalho é identificar casos de testes que permitam validar a adequação, tanto do serviço quanto da aplicação de padrões definidos, de modo a garantir uma maior confiabilidade do sistema como um todo. Para isso, é avaliada a aplicabilidade de técnicas de perturbação e mutação de dados com relação ao padrão estabelecido. Como resultado, obtém-se um subconjunto das técnicas que possuem potencial de identificação de falhas nesse cenário. / Software technology has become essential since it is available in most places. Powered by Internet, nowadays, information quickly flows throw systems. Web Services provide a standard way to meet these objectives, as they use common communication pattern like XML and HTTP. The use of Web Services brings many benefits. On the other hand, it also brings some issues about reliability, availability and other non functional problems. Transactional patterns are an alternative to outline such problems. This study aims to find an effective way to certificate the correct use of those patterns by applying perturbation and mutation testing techniques. As work result, it is expected to determine which of techniques are applicable.

Le Web est devenu une plateforme universelle d’hébergement d'applications hétérogènes. Dans ce contexte, les services Web se sont imposés comme une technologie clé pour permettre l’interaction entre diverses applications. Les technologies standards proposées autour des services Web permettent la programmation, plutôt manuelle, de ces applications. Pour favoriser une programmation automatique à base de services web, un problème majeur se pose : celui de leur découverte. Plusieurs approches adressant ce problème ont été proposées dans la littérature. L’objectif de cette thèse est d’améliorer le processus de découverte de services en exploitant trois pistes de recherche. La première consiste à proposer une approche de découverte qui combine plusieurs techniques de matching. La deuxième se base sur une validation des services retournés par un processus de découverte automatique en se basant sur les compétences utilisateurs. Ces approches ne prennent pas en considération l’évolution de services dans le temps et les préférences des utilisateurs. Pour remédier à ces lacunes plusieurs approches incorporent des techniques de recommandation. La majorité d'entre eux sont basées sur les évaluations des propriétés de QdS. Pratiquement, ces évaluations sont rarement disponibles. D’autres systèmes exploitent les relations de confiance. Ces relations sont établies en se basant sur les évaluations de services. Or, invoquant le même service ne signifie pas obligatoirement avoir les mêmes préférences. D’où, nous proposons, l’exploitation des relations d’intérêts entre les utilisateurs pour recommander des services. L’approche s’appuie sur une modélisation orientée base de données graphes. / The Web has become an universal platform for content hosting and distributed heterogeneous applications that can be accessed manually or automatically. In this context, Web services have established themselves as a key technology for deploying interactions across applications. The standard Web services technologies allow and facilitate the manual programming of these applications. To promote automatic programming based on Web services, a major problem arises : that of their discovery. Several approaches addressing this problem have been proposed in the literature. The aim of this thesis is to improve the Web services discovery process. We proposed three approaches. We proposed a Web services discovery approach that combines several matching techniques. The second consists on the validation of the services returned by an automatic process of discovery using users’ competencies. These approaches do not take into account the evolution of services over time and user preferences. To address these shortcomings, several approaches incorporate referral techniques to assist the discovery process. A large majority of these approaches are based on assessments of QoS properties. In practice, these assessments are rarely available. In other systems, trust relationships between users and services are used. These relationships are established based on invocations evaluations of similar services. However, invoking the same service do not necessarily mean having the same preferences. Hence, we propose, in our third approach, the use of the relations of interest between users to recommend services. The approach relies on modeling services’ ecosystem by database graphs.

To effectively use Web services, providers and consumers need to be connected by a registry. Several registry solutions exist today, including UDDI and WSIL. Also, many organizations simply use Web pages to list available Web services and their descriptions. This research describes a microformat for representing Web service description documents. These microformatted documents can be converted back to the original format for use by machines. They can also contain additional information, making them more useful to people. A registry, allowing indexing and searching of microformatted service descriptions, is also described. The benefits of this solution include: using existing standards; allowing customization of presentation for people; allowing existing search tools to find descriptions; and providing for future, context-based searching to make locating Web services even easier.

This thesis intends to develop application-level access control models to address several major security issues in enterprise environments. The first goal is to provide simple and efficient authorization specifications to reduce the complexity of security management. The second goal is to provide dynamic access control for Web service applications. The third goal is to provide an access control framework for Semantic Web services. In this thesis, an Authorization-Function-Based Role-based Access Control (FB-RBAC) model is proposed for controlling enterprise systems at the application level. The unique features of the proposed model are authorization-function-based access control and constraint-based finegrained access control. This model significantly simplifies the management of an access control system by adopting roles and authorization-functions in authorization specifications. An extension of FB-RBAC, Extended FB-RBAC (ERBAC), is applied to Web service applications. New features such as credential-based access control and dynamic role assignment are added to FB-RBAC in order to address user heterogeneity and dynamicity in the Web environment. The proposed ERBAC model is then extended to support Semantic Web services. Each component of the ERBAC model is described by security ontologies. These correlated security ontologies are integrated with Semantic Web services to form a complete ontology network. Ontology-based role assignment is facilitated so that security information can be queries and discovered through a network of ontologies.