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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.
31

A flexible, policy-aware middleware system

Walker, Scott Mervyn January 2006 (has links)
Middleware augments operating systems and network infrastructure to assist in the creation of distributed applications in a heterogeneous environment. Current middleware systems exhibit some or all of the following five main problems: 1. Decisions must be made early in the design process. 2. Applications are inflexible to dynamic changes in their distribution. 3. Application development is complex and error-prone. 4. Existing systems force an unnatural encoding of application-level semantics. 5. Approaches to the specification of distribution policy are limited. This thesis defines a taxonomy of existing middleware systems and describes their limitations. The requirements that must be met by a third generation middleware system are defined and implemented by a system called the RAFDA Run-Time (RRT). The RRT allows control over the extent to which inter-address-space communication is exposed to programmers, aiding the creation, maintenance and evolution of distributed applications. The RRT permits the introduction of distribution into applications quickly and with minimal programmer effort, allowing for quick application prototyping. Programmers can conceal or expose the distributed nature of applications as required. The RRT allows instances of arbitrary application classes to be exposed to remote access as Web Services, provides control over the parameter-passing semantics applied to remote method calls and permits the creation of flexible distribution policies. The design of the RRT is described and evaluated qualitatively in the context of a case study based around the implementation of a peer-to-peer overlay network. A prototype implementation of the RRT is examined and evaluated quantitatively. Programmers determine the trade off between flexibility and simplicity offered by the RRT on a per-application basis, by concealing or exposing inter-address-space communication. The RRT is a middleware system that adapts to the needs of applications, rather than forcing distributed applications to adapt to the needs of the middleware system.
32

Virtualisation des communications et déploiement d'acteurs matériels : flot de données pour une plateforme hétérogène et reconfigurable dynamiquement / Virtualization of communications in a heterogeneous and dynamically reconfigurable platform

Khiar, Amel 05 November 2014 (has links)
Les applications embarquées ont besoin de plus en plus de puissance de calcul et doivent être déployées sur des architectures spécifiques pour assurer les contraintes non-fonctionnelles du système. Ces architectures peuvent être composées d'unités de calcul hétérogènes, comme des processeurs ou des accélérateurs matériels. Cette hétérogénéité rend le déploiement d'applications de plus en plus complexe, notamment avec l'apparition de circuits reconfigurables dynamiquement. Un des verrous majeurs à ce déploiement réside dans la gestion des communications entre les parties statiques et dynamiques des applications.Le verrou adressé dans cette thèse concerne la gestion des communications entre les blocs fonctionnels de l'application répartis de manière statique en logiciel et de manière dynamique en matériel. Pour faciliter le déploiement des applications existantes et à venir, notre approche s'appuie sur deux contributions complémentaires : une méthodologie de conception basée sur le raffinement progressif d'acteurs flot-de-données, et un middleware distribué assurant les communications entre les acteurs une fois ceux-ci déployés sur la plateforme.Nous avons validé ces concepts sur une application dynamique de suivi de cible en traitement d'images.Dans ce contexte, nous nous sommes intéressés à la virtualisation des communications au sein de la plateforme pour faire communiquer les parties matérielles et logicielles de l'application de manière transparente. Nos contributions ont permis d'aboutir à un démonstrateur opérationnel dans le cadre du projet FOSFOR. / Applications require more computing power and need to be implemented on specific architectures to ensure the non-functioning constraints of the system. These architectures can be composed of heterogeneous processing units, such as processors or hardware accelerators. This heterogeneity makes the deployment of applications on such architectures increasingly complex, especially with the emergence of dynamically reconfigurable devices. One of the hardest obstacles to this deployment is to manage the communication between the static parts and the dynamic ones of the applications.This thesis deals with the communication management issue between the application functional blocks, ones being statically implemented in software, and the others dynamically in hardware. In order to facilitate the deployment of existing applications and those to come, our approach relies on two complementary contributions: a methodology of conception based on the progressive refinement of data-flow actors, and a distributed middleware ensuring the communication between the actors deployed on the platform.These concepts have been validated on a dynamic tracking target application relying on image processing. In this context, we were interested in the virtualization of the communication within the platform in order to allow the communications between the software and the hardware parts of the application in a transparent way. Our contributions permits us to achieve an operational demonstrator in the frame of the FOSFOR project.
33

Monitoração de rede de sensores com transponders. / Sensors network monitoring with transponders.

Foina, Aislan Gomide 16 February 2007 (has links)
Este trabalho apresenta os resultados obtidos no desenvolvimento de um sistema capaz de estabelecer um controle adequado do fluxo da informação e a supervisão de uma rede de sensores. O sistema se caracteriza pelo alto grau de flexibilidade possuindo uma camada de comunicação de dispositivos, uma camada de gerenciamento de regras de negócio para controlar o fluxo de processos, uma camada de interface homem - máquina e de interface com outros sistemas. A camada de comunicação com os dispositivos é responsável pela interface entre os mesmos e o núcleo do sistema, integrando, de forma transparente, diferentes equipamentos, tecnologias e fabricantes. A interface do usuário foi projetada em um único módulo para facilitar modificações sem comprometer o funcionamento geral do sistema. A interface com outros sistemas é feita por meio de drivers de comunicação, permitindo qualquer tipo de integração. O núcleo do sistema faz todo o controle de eventos, do fluxo do processo e geração alarmes, assim como recebimento e envio das informações da camada de dispositivos e da camada de interface. São descritas as diversas camadas da interface e sua implementação analisando as possíveis aplicações do sistema, juntamente com um estudo de caso do controle do processo de descarga de carga a granel no porto de Santos, usando tecnologia RFID. Os resultados obtidos nessa aplicação são descritos e comprovam a utilidade prática do sistema. Apresentam-se inicialmente alguns conceitos básicos necessários ao entendimento deste projeto como: sistemas distribuídos, estrutura webservice, linguagem XML e de tecnologias passíveis de integração com o sistema. / This paperwork presents the results obtained with the development of a system capable of establishing a proper control of information flow and supervision of a sensors network. The system characterizes itself due to its great flexibility degree by having a devices communication layer, a business management layer to do the process flow control, a man-machine interface and interface with other systems layer. The devices communication layer is responsible for the interface between other devices and the system core, integrating in a transparent way, different equipment, technologies and manufactures. The user\'s interface was designed in a single module to facilitate modifications without compromising the system\'s general functioning. The interface with other systems is made throughout communication drivers, allowing any type of integration. The system core makes a control of all events, process flow and alarm generation, as well as receiving and sending information from the devices layer and interface layer. The several interface layers and its implementation are described analyzing the system\'s possible applications along with a case study of loading discharge in a bulk process control at Santos Port using RFID technology. The results obtained with this application are described and prove the practical utility of the system. Some necessary basic concepts to understand this project are presented initially as: distributed systems, web service structure, XML language and technologies subjected to integration with the system.
34

[en] A COLLABORATIVE MODEL FOR EVENT SCHEDULING USING COROUTINES / [pt] UM MODELO DE ESCALONAMENTO COLABORATIVO DE EVENTOS BASEADO EM CORROTINAS

REINALDO XAVIER DE MELLO 04 April 2006 (has links)
[pt] Sistemas orientados a eventos estão se tornando cada vez mais presentes em diversos domínios de aplicação. Sistemas gráficos interativos e sistemas distribuídos são exemplos clássicos de cenários favoráveis ao emprego do paradigma de programação orientada a eventos. Atualmente, novos cenários estão surgindo, tais como os ambientes de programação para telefones celulares e, apesar dessa crescente presença em sistemas computacionais, o paradigma de orientação a eventos ainda apresenta uma série de desafios, tais como a elaboração de mecanismos eficientes para o despacho de eventos e o gerenciamento concorrente da execução desses tratadores, otimizando o uso dos recursos computacionais disponíveis. Este trabalho apresenta um modelo para o desenvolvimento de escalonadores de eventos em ambientes de programação orientados a eventos. É feito um estudo dos principais modelos de escalonamento colaborativo dos eventos, utilizando corrotinas em conjunto com outros padrões de projeto estudados. Defende-se um modelo onde o escalonador é responsável por encapsular a complexidade do gerenciamento de múltiplas linhas de execução colaborativas, procurando otimizar o uso de CPU durante chamadas de métodos bloqueantes. O uso de corrotinas permite o fácil gerenciamento dessas múltiplas linhas de execução, através da definição de mecanismos de abstração de controle, que permitem o encapsulamento do contexto de execução e a suspensão e retomada do processamento de forma transparente ao escalonador e às próprias linhas de execução. O fato de ser um modelo de concorrência colaborativa evita problemas com o controle de acessos concorrentes ao estado compartilhado pelas várias linhas de execução gerenciadas pelo escalonador. O modelo é aplicado em dois cenários distintos: uma ferramenta de programação para telefones celulares, que são inerentemente orientados a eventos de processamento assíncrono e apresentam pouco poder de processamento e fortes restrições no uso da memória disponível; e um middleware CORBA escrito em Lua, onde a comunicação entre os objetos distribuídos é toda baseada no modelo de chamada remota de métodos. / [en] Event oriented systems are becoming present on many domains of applications. Distributed systems and graphical interactive systems are classical examples of environments that adapt well to the concept of event oriented programming. There are also emerging scenarios like cellphone runtime environments. Despite the growing presence on the computational systems, some challenges still remain, like efficient method dispatch models and the management of concurrent processing of the event handlers. This work propose a model for an event scheduler using collaborative routines. We introduce a study on some mainstream scheduler models and propose a model where the scheduler holds the responsibility to encapsulate the complexity of managing multiple lines of execution, minimizing the CPU time wasted with blocking methods. The coroutine model allows the management of these multiple lines of execution using a general control abstraction, which allows seamless context switching during the multiple suspending and resuming of the routine. Also, without preemption, there is no overhead due to access control of the shared resources. The proposed is tested on two different scenarios: one programming framework designed to be run mobile phones, a fully asynchronous environment with low processing power and severe memory constraints; and a CORBA middleware written in lua, where the communication between distributed objects is based on the remote procedure call modell.
35

IDeM: an identity-driven middleware for interoperable and heterogeneous systems

FERRAZ, Felipe Silva 09 September 2016 (has links)
Submitted by Rafael Santana (rafael.silvasantana@ufpe.br) on 2017-08-30T18:59:54Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Thesis_final_v8_final.pdf: 3606329 bytes, checksum: 9eb076ad648eb48bf1a1cac89fb53d9b (MD5) / Made available in DSpace on 2017-08-30T18:59:54Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Thesis_final_v8_final.pdf: 3606329 bytes, checksum: 9eb076ad648eb48bf1a1cac89fb53d9b (MD5) Previous issue date: 2016-09-09 / In mid-2000s, for the first time in human history, urban cities started to harbor more than half of world's population. The concept of Smart Cities emerged in such context. Smart Cities can be defined as an urban environment where innovative services under an available infrastructure are provided to citizens with the use of information technology (IT). However, even though people use and take advantage of available information, there is a natural resistance to disclosure and expose personal data, which will get known by other citizens and businesses. This generates a sense of insecurity and privacy loss. This thesis explores information security issues related to identity and identifier management and proposes a solution that guarantees the privacy and anonymity of users within interoperable and heterogeneous environments. This thesis proposes a solution based on the creation of a multi identity environment, in which a user has different identities, for different systems using the same identifier, that way it is possible to connect with different services, solutions and others, using the same login but having different representations within each solution, that will guarantee privacy, different level of security and interoperability. The proposed solution is demonstrated through the creation of a middleware within the context of smart cities. Finally, this thesis presents a set of experiments that use the proposed middleware to protect citizens’ sensitive data. / Em meados dos anos 2000, pela primeira vez na história da humanidade, as grandes cidades começaram a abrigar mais da metade da população mundial. É no contexto dessa mudança que surge o conceito de Smart Cities, tal conceito pode ser definido como um ambiente urbano onde, com uso de tecnologia da informação, serviços inovadores e com infraestrutura disponível, são fornecidos para os cidadãos. Em contra ponto a essa dinâmica está o fato de que essas mesmas pessoas, que fazem uso das informações, tem uma resistência natural relacionada a divulgação de seus dados, e que estes sejam expostos e conhecidos por demais cidadões e empresas, gerando um cenário de insegurança e perda de privacidade. Este trabalho explora problemas de segurança da informação relacionados a gerenciamento de identidade e identificadores, propõe a criação de uma solução que permita manter a privacidade e o anonimato de usuários, ainda que anônimo, dentro de ambientes interoperáveis e heterogêneos. Essa tese propõe um solução baseada na creação de um ambiente multi identidade, no qual um usuário terá diferentes identidades, para diferentes sistemas, usando o mesmo identificador, dessa forma é possivel garantir a conexão com diferentes serviços, soluções e outros componentes, usando o mesmo login, por exemplo, porém tendo diferentes representações em cada solução, isso garantirá, entre outros, privacidade, diferentes niveis de segurança e interoperabilidade. Tal solução será descrita na forma de um middleware explorado dentro do contexto de cidades inteligente. Por fim, este trabalho apresentará um conjuntos de experimentos que utilizam o middleware, para proteger dados confidenciais dos cidadãos.
36

Monitoração de rede de sensores com transponders. / Sensors network monitoring with transponders.

Aislan Gomide Foina 16 February 2007 (has links)
Este trabalho apresenta os resultados obtidos no desenvolvimento de um sistema capaz de estabelecer um controle adequado do fluxo da informação e a supervisão de uma rede de sensores. O sistema se caracteriza pelo alto grau de flexibilidade possuindo uma camada de comunicação de dispositivos, uma camada de gerenciamento de regras de negócio para controlar o fluxo de processos, uma camada de interface homem - máquina e de interface com outros sistemas. A camada de comunicação com os dispositivos é responsável pela interface entre os mesmos e o núcleo do sistema, integrando, de forma transparente, diferentes equipamentos, tecnologias e fabricantes. A interface do usuário foi projetada em um único módulo para facilitar modificações sem comprometer o funcionamento geral do sistema. A interface com outros sistemas é feita por meio de drivers de comunicação, permitindo qualquer tipo de integração. O núcleo do sistema faz todo o controle de eventos, do fluxo do processo e geração alarmes, assim como recebimento e envio das informações da camada de dispositivos e da camada de interface. São descritas as diversas camadas da interface e sua implementação analisando as possíveis aplicações do sistema, juntamente com um estudo de caso do controle do processo de descarga de carga a granel no porto de Santos, usando tecnologia RFID. Os resultados obtidos nessa aplicação são descritos e comprovam a utilidade prática do sistema. Apresentam-se inicialmente alguns conceitos básicos necessários ao entendimento deste projeto como: sistemas distribuídos, estrutura webservice, linguagem XML e de tecnologias passíveis de integração com o sistema. / This paperwork presents the results obtained with the development of a system capable of establishing a proper control of information flow and supervision of a sensors network. The system characterizes itself due to its great flexibility degree by having a devices communication layer, a business management layer to do the process flow control, a man-machine interface and interface with other systems layer. The devices communication layer is responsible for the interface between other devices and the system core, integrating in a transparent way, different equipment, technologies and manufactures. The user\'s interface was designed in a single module to facilitate modifications without compromising the system\'s general functioning. The interface with other systems is made throughout communication drivers, allowing any type of integration. The system core makes a control of all events, process flow and alarm generation, as well as receiving and sending information from the devices layer and interface layer. The several interface layers and its implementation are described analyzing the system\'s possible applications along with a case study of loading discharge in a bulk process control at Santos Port using RFID technology. The results obtained with this application are described and prove the practical utility of the system. Some necessary basic concepts to understand this project are presented initially as: distributed systems, web service structure, XML language and technologies subjected to integration with the system.
37

Services for safety-critical applications on dual-scheduled TDMA networks

Rosset, Valerio January 2009 (has links)
Tese de doutoramento. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 2009
38

Axon: A Middleware for Robotics

Morckos, Michael January 2012 (has links)
The area of multi-robot systems and frameworks has become, in recent years, a hot research area in the field of robotics. This is attributed to the great advances made in robotic hardware, software, and the diversity of robotic systems. The need to integrate different heterogeneous robotic components and systems has led to the birth of robotic middleware. A robotic middleware is an intricate piece of software that masks the heterogeneity of underlying components and provides high-level interfaces that enable developers to make efficient use of the components. A large number of robotic middleware programs exist today. Each one comes with its own design methodologies and complexities. Up to this moment, however, there exists no unified standard for robotic middleware. Moreover, many of the middleware in use today deal with low-level and hardware aspects. This adds unnecessary complexity in research involving robotic behavior, inter-robot collaboration, and other high-level experiments which do not require prior knowledge of low-level details. In addition, the notion of structured lightweight data transfer between robots is not emphasized in existing work. This dissertation tackles the robotic middleware problem from a different perspective. The aim of this work is to develop a robust middleware that is able to handle multiple robots and clients within a laboratory environment. In the proposed middleware, a high-level representation of robots in an environment is introduced. Also, this work introduces the notion of structured and efficient data exchange as an important issue in robotic middleware research. The middleware has been designed and developed using rigorous methodologies and leading edge technologies. Moreover, the middleware’s ability to integrate different types of robots in a seamless manner, as well as its ability to accommodate multiple robots and clients, has been tested and evaluated.
39

Axon: A Middleware for Robotics

Morckos, Michael January 2012 (has links)
The area of multi-robot systems and frameworks has become, in recent years, a hot research area in the field of robotics. This is attributed to the great advances made in robotic hardware, software, and the diversity of robotic systems. The need to integrate different heterogeneous robotic components and systems has led to the birth of robotic middleware. A robotic middleware is an intricate piece of software that masks the heterogeneity of underlying components and provides high-level interfaces that enable developers to make efficient use of the components. A large number of robotic middleware programs exist today. Each one comes with its own design methodologies and complexities. Up to this moment, however, there exists no unified standard for robotic middleware. Moreover, many of the middleware in use today deal with low-level and hardware aspects. This adds unnecessary complexity in research involving robotic behavior, inter-robot collaboration, and other high-level experiments which do not require prior knowledge of low-level details. In addition, the notion of structured lightweight data transfer between robots is not emphasized in existing work. This dissertation tackles the robotic middleware problem from a different perspective. The aim of this work is to develop a robust middleware that is able to handle multiple robots and clients within a laboratory environment. In the proposed middleware, a high-level representation of robots in an environment is introduced. Also, this work introduces the notion of structured and efficient data exchange as an important issue in robotic middleware research. The middleware has been designed and developed using rigorous methodologies and leading edge technologies. Moreover, the middleware’s ability to integrate different types of robots in a seamless manner, as well as its ability to accommodate multiple robots and clients, has been tested and evaluated.
40

Lightweight distributed service platform for adaptive mobile services /

Pakkala, Daniel. January 2004 (has links) (PDF)
Diplomityö -- Oulun yliopisto. sähkö- ja tietotekniikan osasto. / Abstract in English and Finnish. Includes bibliographical references (p. 139-145). Also available on the World Wide Web.

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