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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
401

Modeling and analysis of security

Unknown Date (has links)
Cloud Computing is a new computing model consists of a large pool of hardware and software resources on remote datacenters that are accessed through the Internet. Cloud Computing faces significant obstacles to its acceptance, such as security, virtualization, and lack of standardization. For Cloud standards, there is a long debate about their role, and more demands for Cloud standards are put on the table. The Cloud standardization landscape is so ambiguous. To model and analyze security standards for Cloud Computing and web services, we have surveyed Cloud standards focusing more on the standards for security, and we classified them by groups of interests. Cloud Computing leverages a number of technologies such as: Web 2.0, virtualization, and Service Oriented Architecture (SOA). SOA uses web services to facilitate the creation of SOA systems by adopting different technologies despite their differences in formats and protocols. Several committees such as W3C and OASIS are developing standards for web services; their standards are rather complex and verbose. We have expressed web services security standards as patterns to make it easy for designers and users to understand their key points. We have written two patterns for two web services standards; WS-Secure Conversation, and WS-Federation. This completed an earlier work we have done on web services standards. We showed relationships between web services security standards and used them to solve major Cloud security issues, such as, authorization and access control, trust, and identity management. Close to web services, we investigated Business Process Execution Language (BPEL), and we addressed security considerations in BPEL and how to enforce them. To see how Cloud vendors look at web services standards, we took Amazon Web Services (AWS) as a case-study. By reviewing AWS documentations, web services security standards are barely mentioned. We highlighted some areas where web services security standards could solve some AWS limitations, and improve AWS security process. Finally, we studied the security guidance of two major Cloud-developing organizations, CSA and NIST. Both missed the quality of attributes offered by web services security standards. We expanded their work and added benefits of adopting web services security standards in securing the Cloud. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2013.
402

Identificação e tratamento dos problemas de desempenho de redes de sensores expostas por arquiteturas orientadas a serviço / Identification and treatment of performance problems in sensor network exposed by service oriented architectures

Tavares, Thiago Caproni 11 June 2014 (has links)
Este trabalho de doutorado tem como objetivo principal mostrar que a abstração de redes de sensores, por meio de arquiteturas orientadas a serviço, pode impor alguma degradação do desempenho, mas não inviabiliza a maioria das aplicações. A metodologia utilizada na condução deste trabalho consta de experimentos que realizam avaliações de desempenho que analisam o comportamento de diferentes mecanismos de exposição de redes de sensores, bem como avalia três dos principais serviços do modelo de interfaces do Sensor Web Enablement (SWE). Os resultados obtidos mostram diferenças de desempenho significativas entre os métodos de acesso considerados. Esses resultados ainda mostram que a sobrecarga gerada não é significativa se comparada com a frequência de obtenção de observações da maioria das redes de sensores. Visando minimizar os problemas de desempenho impostos pelo framework SWE é proposta e implementada uma arquitetura de provisão de qualidade de serviço (QoS), denominada Sensor Web Architecture (SWARCH). Um estudo de caso da SWARCH demonstra que é possível reduzir os tempos de resposta no acesso aos serviços do SWE por meio de um Broker que monitora constantemente diferentes provedores de serviços / This PhD work aims to show that the abstraction of sensor networks, by means of service-oriented architectures, may impose some performance degradation, but it does not invalidate most applications. The methodology used to conduct this research consists of experiments that realize performance evaluations that analyze the behavior of different mechanisms of exposure of sensor networks, and evaluates the three major services of the Sensor Web Enablement (SWE) model interfaces. The results show significant differences in performance between the methods of considered access. The results also show that the generated overhead is not significant when compared with the frequency of obtaining observations of most wireless sensor networks. Aiming to minimize the performance issues imposed by the SWE framework, an architecture providing quality of service (QoS) called Sensor Web Architecture (SWARCH) is proposed and implemented. A case study of SWARCH demonstrates that it is possible to reduce response times when accessing the SWE services through a Broker that constantly monitors various service providers
403

Usando Serviços Web para integrar aplicações cientes de contexto / Applying Web services to integrate context-aware applications

Jardim, Carlos Henrique Odenique 20 March 2006 (has links)
A Computação Ubíqua está revolucionando a interação do ser-humano com os dispositivos computacionais ao disponibilizar tecnologias pouco intrusivas ao cotidiano das pessoas. A Computação Ciente de Contexto, um dos temas de pesquisa em Computação Ubíqua, tem contribuído para a construção de aplicações capazes de customizar-se e adaptar-se às necessidades do usuário sem a intervenção explícita deste. Suportar o desenvolvimento de aplicações Cientes de Contexto é um dos desafios da Computação Ubíqua. Desenvolvido no mesmo grupo de pesquisa que este trabalho está inserido, o Serviço Web Context Kernel, gerencia informações de contexto e explora as especificações e tecnologias da Web como plataforma de intercâmbio para a informação contextual. O trabalho aqui reportado teve como objetivo investigar a utilização de Serviços Web por meio do emprego da infra-estrutura Context Kernel na integração de aplicações em cenários de trabalho colaborativo e de aprendizado eletrônico. Como resultado, foi elaborado um conjunto de lições aprendidas provenientes do estudo e do emprego das especificações para Serviços Web. Outros resultados foram: as especificações de informações de contexto de grupo e de metadados educacionais em dimensões de contexto e exemplos de utilização do Context Kernel para tornar aplicações cientes de contexto. / Ubiquitous computing has became a revolution in terms of the user-computer interaction by providing technologies that seamlessly integrate themselves to people?s everyday life. Context-aware computing, which is an important research theme in ubiquitous computing, has been contributing for the building of applications that are capable both to customize and adapt themselves aiming to support a user without disturb him. A great challenge in ubiquitous computing has been the support to build context-aware aplications. For that reason, the it has been developed the Context Kernel Web Service, which is a service infrastructure that makes use of Web-based specifications and technologies in order to promote the management and the interchange of context information. In this work the usage of Web Services was analyzed by using the Context Kernel to integrate applications in scenarios of cooperative work and e-learning. As a result, a list of lessons learned was ellaborated with respect to the use and the study of Web Services specifications for context-aware computing. Other results include a context information specifications for metadata about group and educational resources as well as examples of how to use the Context Kernel to leverage applications context-aware.
404

Performance analysis of Web Services : Comparison between RESTful & GraphQL web services

Helgason, Arnar Freyr January 2017 (has links)
In today's interconnected world, we as users constantly demand more information to be accessible from the web. Not only should the data be accessible but a crucial factor is that load times should be fast. With the internet expanding to more devices of different types such as smartphones, tablets, IoT devices and more, this factor becomes even more important. The most commonly used service today for serving data between clients and a server is REST, which has been the leading service used for this purpose for many years. This research paper focuses on identifying the differences in performance between RESTful services and Facebook's GraphQL. These two technologies are the two most commonly used and talked about solutions when it comes to serving data between clients and servers as of today, with more developers moving towards the newer GraphQL.
405

Implementação de mecanismos tolerantes a falhas em uma arquitetura SOA com Qos / Implementation of fault tolerant mechanisms in a SOA architecture with QoS

Oliveira, Edvard Martins de 28 August 2013 (has links)
Esta dissertação de mestrado tem como objetivo avaliar a integração de políticas de tolerância a falhas em uma arquitetura de Web Services com múltiplos módulos. A arquitetura utilizada é denominada WSARCH, e foi desenvolvida para o estudo das relações e interoperabilidade entre serviçcos. Os mecanismos de tolerência a falhas foram integrados aos módulos da arquitetura, testados, comparados e avaliados. A avaliação de desempenho mostrou que os mecanismos de tolerância a falhas introduzidos foram eficientes e apresentaram resultados adequados. As técnicas de reputação utilizadas na seleção de serviço atuaram satisfatoriamente e foram consideradas um importante avanço nos mecanismos da arquitetura / This master\'s thesis aims to evaluate the integration of fault tolerance mechanisms in a Web Services architecture with multiple modules. The architecture used is named WSARCH and was developed for the study of interactions and interoperability of services. WSARCH is an architecture conceived to receive tests and experiments involving concepts of Web Services. The fault tolerance tools were integrated in the architecture, tested, evaluated and comparated. The performance evaluation showed that the fault tolerance mechanisms introduced were ecient and presented appropriate results. The reputation techniques utilized in service selection operated successfully and were considered an important advance in the mechanisms of the architecture
406

Best friend influence over adolescent problem behaviors: the role of perceived friendship quality

Unknown Date (has links)
Close friends have been shown to influence adolescent problem behaviors, especially alcohol abuse (Urberg, Degirmencioglu, and Pilgrim, 1997). The degree of influence, however varies as a function of individual characteristics such as peer acceptance (Laursen, Hafen, Kerr, and Stattin, 2012) and age (Popp et al., 2008). The present study examines whether differences in influence extend to perceptions of friendship quality. Using a sample of 764 Swedish adolescents involved in stable samesex reciprocal best friend relationships that lasted at least one year, analyses used distinguishable dyad actor-partner interdependence model (APIM) analyses (Kenny, Kashy, & Cook, 2006) to track influence over two years of the friendship. More satisfied friends were more influential than less satisfied friends on intoxication frequency and truancy. The findings of this study indicate that influence accompanies perceptions of quality. Those with higher perceptions of quality exhibit more influence on friends who perceive relatively lower quality. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2013.
407

Communication and interactivity in B2B relationships

Unknown Date (has links)
This research explores the impact of interactive communication on business-to business (B2B) relationships. In the past decade the internet and especially social media as a mode of communication has grown rapidly in both consumer and business markets. Drawing on marketing channels and communications literature this paper identifies the dimensions of interactive communication and develops a theoretical framework to examine their impact on satisfaction, commitment, and advocacy. Media synchronicity theory and the concept of the internet as an alternative to the real world are used to distinguish between digital and non-digital modes of communication. Relationship marketing is used to identify the dimensions of interactivity: rationality, social interaction, contact density, and reciprocal feedback. The framework developed is usedto explore the influence of face-to-face (F2F), digital, and traditional, impersonalcommunications on the dimensions of interactivity.Hypotheses linking the mode of communication: personal, digital, and impersonal with the dimensions of interactivity and relational outcomes are empirically examined with data from the commercial printing and graphic design industry. Confirmatory Factor Analysis is used to analyze the measurement and structural model. Personal, F2F communication has the greatest impact on social interaction, reciprocal feedback, and number of contacts. Digital communication has a weaker effect on these dimensions and impersonal communication has the weakest effect. Personal and Digital have equal impacts on rationality and rationality is the only dimension of interactivity positively associated with relationship satisfaction. Contact density has a negative impact on relationship satisfaction and this negative impact is greater with personal communication that it is with digital. The study shows that affective commitment leads to advocacy in a B2B channel, but trust and calculative commitment have no impact on advocacy. The findings of the study have implications for both managers and researchers regarding the mode and content of communications in B2B relationships. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2013.
408

APRON : agent-based specification and procurement of construction products

Obonyo, Esther Adhiambo January 2004 (has links)
This thesis presents a study of the fragmented nature of activities involved in the specification and procurement of construction products. Existing Internet-based approaches have perpetuated fragmentation in this domain and this has resulted in a problem known as 'digital anarchy.' The thesis describes the design and development of an application based on the metaphor of software agents to address this problem. The thesis has validated the view that failures in the existing approaches have resulted in the 'digital anarchy' problem. Such approaches have failed to eradicate paper-based communication patterns and its related sequential work methods. The thesis has established the proof of concept of using agents for the management of distributed information in the selected domain. The work has also synthesised agent technology, XML and Web Services into a cohesive architecture, demonstrating that the ultimate solution to the 'digital anarchy' problem will emerge from a synergy of the various streams of research in Internet-related technologies. The work has established that there is significant scope for systematic improvement in the specification and procurement of construction products listed on the Internet based on the agent paradigm.
409

Caracterização de cargas de trabalho para avaliação de desempenho em Web services / Workload Characterization for Performance Evaluation in Web Services

Tavares, Thiago Caproni 02 July 2009 (has links)
Esta dissertação de mestrado aborda um estudo sobre a caracterização de cargas de trabalho para Web services por meio da análise de Documentos WSDL (Web Service Description Language). Esses documentos, que representam a interface para os serviços, foram obtidos na Web e seus conteúdos analisados estatisticamente. A metodologia utilizada para alcançar a caracterização desejada, constitui-se da coleta e análise dos dados de 1346 arquivos WSDL válidos. O resultado do estudo proposto nesta dissertação contribui para a avaliação de desempenho no que diz respeito a caracterizar os diversos aspectos das cargas de trabalho de Web services. Dentre os dados obtidos ressaltam-se as porcentagens da ocorrência de algumas características tais como o número de operações, tipos de Binding, quantidade de parâmetros de entrada e saída e tipos de dados mais utilizados. Para auxiliar na busca e avaliação das características das WSDLs uma nova ferramenta denominada WSDLAnalyzer é proposta e implementada / This MSc dissertation approaches a study on workload characterization for web services by means of the analysis of WSDL (Web Service Description Language) documents. These documents, that represent the interface to the services, were all obtained in the web and their contents were statistically analyzed. The methodology used to reach the desired characterization comprises the collection and analysis of 1346 WSDL valid files. The result of the study proposed in this dissertation contributes to the performance evaluation of web services in terms of characterizing the several aspects of the workloads. Among the data obtained, the percentage of occurrences of some features, such as the number of operations, the types of binding, the amount of input and output parameters and the more used data types, are highlighted. To support the search and evaluation of the WSDL features a new tool, named WSDLAnalyzer, is proposed and implemented
410

Modelagem de contexto utilizando ontologias. / Context modeling using ontologies.

Ponce Escobedo, Edgardo Paúl 05 May 2008 (has links)
Com os avanços dos processos da microeletrônica temos dispositivos menores e com maior poder de computação e comunicação. Um Ambiente Pervasivo contém diferentes dispositivos, tais como sensores, atuadores, eletroeletrônicos e dispositivos móveis que interagem com a pessoa de forma natural ao conhecer o contexto. A diversidade de dispositivos e informações do Ambiente Pervasivo introduz um problema de interoperabilidade. Um Ambiente Pervasivo é dinâmico devido à mobilidade do usuário, a variedade de dispositivos. Neste trabalho, é proposto um modelo semântico de contexto para permitir interoperabilidade e fornecer suporte ao dinamismo do Ambiente Pervasivo. O modelo proposto contém características da modelagem de contexto realizadas por trabalhos anteriores, assim como sua integração com a modelagem de preferências das pessoas, políticas de privacidade e serviços. Verificou-se que o modelo de contexto proposto é adequado mediante sua aplicação em um Estudo de Caso e mediante testes realizados. Mostra-se que a modelo de contexto utilizado ontologias e Serviços Web Semânticos permite tratar com informação incompleta e inconsistente, bem como fornece suporte na interoperabilidade e ao dinamismo do Ambiente Pervasivo. / Advances in microelectronic processes have allowed smaller devices with more computation and communication power. Pervasive environment contains different devices like electronic sensor, actuators and mobile devices which interact with the person naturally after the context is known. The device and information diversity introduce an interoperability problem. Pervasive environments are dynamics because of user\'s mobility and a variety of devices. In this work, we propose a context model to allow interoperability and to give support to pervasive environment dynamism. The proposed model contains features of context modeling developed in previous works, as well as, their integration with the modeling of the people\'s preferences, privacy policies and services. It was verified that the context model is appropriate by their application in a Case Study and by accomplished tests. It is shown that the model of context using ontologies and Semantic Web Services allow us to work with inconsistent and incomplete information, as well as gives support to interoperability and dynamism of the Pervasive Environment.

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