68 research outputs found

    Demonstrador de mobilidade heterogénea

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    No âmbito da cadeira de projecto do curso de Engenharia de Computadores e Telemática, desenvolveu-se um demonstrador de mobilidade heterogénea tendo por base o projecto Europeu Moby Dick. Para além da construção do mesmo desenvolveram-se alguns pacotes de software que constituem uma mais valia para o demontrador. Por fim realizaram-se vários testes sobre o demonstrador cujos resultados são aqui apresentados.Integrated in Computers and Telematics Engineer final project, a Heterogenity and Mobility Demo was setup, using as it base the European Project Moby Dick. Having the Demo setup further software packages were developed constituting an increased value to the Demo. All done several tests were performed on the Demo whose results are presented here

    Síntese e implementação de circuitos digitais reconfiguráveis dinamicamente (projecto 2)

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    The paper presents the results of the project proposed to the authors (who are the 4th year students of LECT) and shows how the specified problem has been solved. The description of the project and the basic requirements have been considered in the papers [1,2

    User-hosted SOA infrastructure over XMPP

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    The principles of Service-Oriented Architecture (SOA) argue for the design of systems composed of re-usable coarse-grained software components which consume and provide services in a service ecosystem. Despite being commonly mentioned in an enterprise context, these are very present in the web - most web applications expose some of their data via APIs, which are then used by other web and mobile applications. The proliferation of user-owned connected devices has brought value to mobile application developers which can make use of locally-available sensors and capabilities and send their information to the web, centralizing the data flows. A more distributed approach would have device capabilities offered directly on the network as services hosted by the user. These pervasive user-hosted services could be made discoverable and available over a public federated service infrastructure. The infrastructure would provide transport over an identity layer, where endpoints are addressed by their identities instead of network identifiers, and on top of which services can be exposed to be consumed by trusted friends or anonymous users, as the hosting user prefers. The work presented in this paper explores the possibility of implementing a distributed social SOA over Extensible Messaging and Presence Protocol (XMPP). It differs from traditional SOA because it attempts to counter relative centralization of the web, in favour of a fully-distributed service ecosystem where each peer can behave both as service consumer and provider. Finally, an analysis is done on how suitable XMPP is to serve as a base protocol for such infrastructure

    Towards behaviour inference in smart environments

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    Smart environments are physical places that are richly and invisibly populated with sensors, actuators and computational elements. The objective of such environments is to adapt themselves to its users in order to increase their comfort and usefulness. This paper proposes a platform, named APOLLO, capable of inferring behaviour rules from a smart environment and apply them to provide an intelligent space. The APOLLO platform is built upon a Service Oriented Architecture (SOA), in which collected context information is used to infer behaviour rules though statistical and machine learning techniques. The proposed platform is to be deployed in a home automation scenario

    Sistema de apoio a organização e gestão de conferências cientificas (CoW – Conference on the Web)

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    Este artigo pretende divulgar o software de organização e gestão de conferências científicas Conference on the Web (CoW). Software este desenvolvido por alunos finalistas de Eng. Computadores e Telemática na cadeira de opção de 5º ano, de Ferramentas e Aplicacionais Multimédia.This article intends to divulge software developed to help in the organization and management of Scientific Conferences on the Web (CoW). This Software package was developed by last year students of Eng. Computadores and Telemática in 5º year optional subject Ferramentas and Aplicacionais Multimédia

    Optimização de recursos para difusão em redes de próxima geração

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    Doutoramento em ElectrotecniaEsta tese aborda o problema de optimização de recursos de rede, na entrega de Serviços de Comunicação em Grupo, em Redes de Próxima Geração que suportem tecnologias de difusão. De acordo com esta problemática, são feitas propostas que levam em atenção a evolução espectável das redes 3G em Redes Heterogéneas de Próxima Geração que incluam tecnologias de difusão tais como o DVB. A optimização de recursos em Comunicações em Grupo é apresentada como um desafio vertical que deve cruzar diversas camadas. As optimizações aqui propostas cobrem tanto a interface entre Aplicação e a Plataforma de Serviços para a disponibilização de serviços de comunicação em grupo, como as abstracções e mapeamentos feitos na interface entre a Rede Central e a Rede de Acesso Rádio. As optimizações propostas nesta tese, assumem que o caminho evolutivo na direcção de uma Rede de Próxima Geração é feito através do IP. Em primeiro lugar são endereçadas as optimizações entre a Aplicação e a Plataforma de Serviços que já podem ser integradas nas redes 3G existentes. Estas optimizações podem potenciar o desenvolvimento de novas e inovadoras aplicações, que através do uso de mecanismos de distribuição em difusão podem fazer um uso mais eficiente dos recursos de rede. De seguida são apresentadas optimizações ao nível da interface entre a Rede Central e a Rede de Acesso Rádio que abordam a heterogeneidade das redes futuras assim como a necessidade de suportar tecnologias de difusão. É ainda considerada a possibilidade de aumentar a qualidade de serviço de serviços de difusão através do mapeamento do IP multicast em portadoras unidireccionais. Por forma a validar todas estas optimizações, vários protótipos foram desenvolvidos com base num router avançado para redes de acesso de próxima geração. As funcionalidades e arquitectura de software desse router são também aqui apresentadas.This thesis addresses the problem of optimizing network resource usage, for the delivery of Group Services, in Next Generation Networks featuring broadcast technologies. In this scope, proposals are made according to the expected evolution of 3G networks into Next Generation Heterogeneous Networks that include broadcast technologies such as DVB. Group Communication resource optimization is considered a vertical challenge that must cross several layers. The optimizations here proposed cover both Application to Service Platform interfaces for group communication services, and Core Network to Radio Access Network interface abstractions and mappings. The proposed optimizations are also presented taking into consideration network evolution path towards an All-IP based Next Generation Network. First it is addressed the Application to Service Platform optimization, which can already be deployed over 3G networks. This optimization could potentiate the development of new and innovative applications that through the use of broadcast/multicast service delivery mechanisms could be more efficient network wise. Next proposals are made on the Core Network to Radio Access Network interfaces that address the heterogeneity of future networks and consider the need to support broadcast networks. It is also considered the possibility to increase the Quality of Service of broadcast/multicast services based on the dynamic mapping of IP multicast into unicast radio bearers. In order to validate these optimizations, several prototypes were built based on an advanced access router for next generation networks. Such access router functionalities and software architecture are also presented here

    Semantic-based publish/subscribe for M2M

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    The number of connected devices is expected to soar in the coming years, each one of them collects and distributes real-world information though various systems. As the number of such connected devices grows, it becomes increasingly difficult to store and share all these new sources of information. Several context representation schemes try to standardize this information, however none of them have been widely adopted. Publish/ subscribe paradigm has proven to be an adequate abstraction for large scale information dissemination, but none of current variations is well suited for context information. In a previous publication we addressed these challenges, however our solution has some drawbacks: poor scalability and semantic extraction. The aim of this paper is twofold. First, we discuss an efficient way to deal with representation schemes diversity and propose a d-dimensional context organization model. Second, we propose a semantic-based publish/subscribe system that is well suited for M2M scenarios. Our evaluation shows that d-dimensional organization model outperforms our previous solution in both speed and space requirements

    Context storage using NoSQL

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    With the ubiquity and pervasiveness of mobile computing, together with the increasing number of social networks, end-users have learned to live and share all kinds of information about themselves. As an example, Facebook reports that it has currently 500 million active users, 200 million of which access its services on mobile systems; moreover, users that access Facebook through mobile applications are twice as active as non-mobile users, and it is used by 200 mobile operators in 60 countries [1]. More specific mobile platforms such as Foursquare, which unlike Facebook only collects location information, reports 6.5 million users worldwide, and also has a mobile presence (both with a web application and iPhone / Android applications) [2]. Context- aware architectures intend to explore this increasing number of context information sources and provide richer, targeted services to end-users, while also taking into account arising privacy issues. While multiple context management platform architectures have been devised [3], this paper focuses primarily on Context- Broker-based architectures, such as the ones proposed in the projects Mobilife [4] and C-Cast [5]. More specifically, it focuses on the context management platform XCoA [6]. This platform uses XMPP for its main communication protocol, and publishes context information in a Context-Broker. This context information is provided by Context-Agents, such as mobile terminals, sensor networks and social networks. Due to the nature of the XMPP protocol, the context information is provided in XML form. This paper proposes the usage of a NoSQL storage system for the purpose of context information storage and retrieval in an XMPP broker-based context platform such as XCoA, together with a full-text searching engine. Through a comparison made through prototypes, the paper clearly demonstrates the advantages of NoSQL storage systems applied to the area of Context Management

    Context storage for M2M scenarios

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    As the number of environmental sensors grows, it becomes increasingly difficult to manage, store and process all these sources of information. Several context representation schemes try to standardize this information, however none of them have been widely adopted. Instead of proposing yet another context representation scheme, we discuss efficient ways to deal with this diversity of representation schemes. We defined the basic requirements for flexible context storage systems, proposed an implementation and compared our implementation against two other approaches. Our solution provides more value than the remaining solutions without suffering a significant decrease in performance

    An architecture for the future business of things

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    A brave new world made of interconnected smart devices will soon revolutionize the world. The application of the Internet of Things vision will foster the creation of new businesses across different industrial sectors. Communication Service Providers need to set the pace of this change if they want to lead this transformation. They need to both leverage and evolve their architectures in order to support a flexible creation of innovative services over distributed networks, linking heterogeneous sensors and actuators. This paper presents the roles of the telecoms on the upcoming machine-to-machine markets and devises an advanced architecture able to withstand the demands of a new plethora of evermore clever and useful services
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