232 research outputs found
The LEAF Platform: Incremental Enhancements for the J2EE
LEAF, the Lean and Extensible Architectural Framework, is an enhancement wrapper for J2EE implementations. Basically, LEAF fixes some identified J2EE issues and extends, as well as simplifies, the use of the J2EE by providing several incremental improvements. These improvements are seamlessly integrated, include an additional component type, allow the same interfaces for local and remote service implementations, offer better J2EE implementation compatibility and ORB interceptors, and encompass several new technical services. This paper explains the need for LEAF through a diagnosis of the J2EE, presents the fundamental concepts underlying LEAF, overviews its implementation, reports on field experiences from using it in a number of commercial projects, and points out some interesting tradeoffs in using the J2EE with and without LEAF
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Multimedia delivery in the future internet
The term âNetworked Mediaâ implies that all kinds of media including text, image, 3D graphics, audio
and video are produced, distributed, shared, managed and consumed on-line through various networks,
like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white
paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked
challenges of the Networked Media in the transition to the Future of the Internet.
Internet has evolved and changed the way we work and live. End users of the Internet have been confronted
with a bewildering range of media, services and applications and of technological innovations concerning
media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace
of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more
than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so
regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected
to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising
to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged
that in a near- to mid-term future, the Internet will provide the means to share and distribute (new)
multimedia content and services with superior quality and striking flexibility, in a trusted and personalized
way, improving citizensâ quality of life, working conditions, edutainment and safety.
In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe
network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as
community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of
interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and
innovative applications âon the moveâ, like virtual collaboration environments, personalised services/
media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content
combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P
networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to
contribute towards such a vision.
Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6)
and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily
contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way
ahead in the area of Content Aware media delivery platforms
Security in Distributed, Grid, Mobile, and Pervasive Computing
This book addresses the increasing demand to guarantee privacy, integrity, and availability of resources in networks and distributed systems. It first reviews security issues and challenges in content distribution networks, describes key agreement protocols based on the Diffie-Hellman key exchange and key management protocols for complex distributed systems like the Internet, and discusses securing design patterns for distributed systems. The next section focuses on security in mobile computing and wireless networks. After a section on grid computing security, the book presents an overview of security solutions for pervasive healthcare systems and surveys wireless sensor network security
VISOR: virtual machine images management service for cloud infarestructures
Cloud Computing is a relatively novel paradigm that aims to fulfill the computing as utility dream. It has appeared to bring the possibility of providing computing resources (such as servers, storage and networks) as a service and on demand, making them accessible through common Internet protocols. Through cloud offers, users only need to pay for the amount of resources they
need and for the time they use them. Virtualization is the clouds key technology, acting upon virtual machine images to deliver fully functional virtual machine instances. Therefore, virtual machine images play an important role in Cloud Computing and their efficient management becomes a key concern that should be carefully addressed. To tackle this requirement, most cloud offers provide their own image repository, where images are stored and retrieved from, in order to instantiate new virtual machines. However, the rise of Cloud Computing has brought
new problems in managing large collections of images.
Existing image repositories are not able to efficiently manage, store and catalogue virtual machine images from other clouds through the same centralized service repository. This becomes especially important when considering the management of multiple heterogeneous cloud offers. In fact, despite the hype around Cloud Computing, there are still existing barriers to its widespread adoption. Among them, clouds interoperability is one of the most notable issues.
Interoperability limitations arise from the fact that current cloud offers provide proprietary interfaces, and their services are tied to their own requirements. Therefore, when dealing with multiple heterogeneous clouds, users face hard to manage integration and compatibility issues.
The management and delivery of virtual machine images across different clouds is an example of such interoperability constraints.
This dissertation presents VISOR, a cloud agnostic virtual machine images management service and repository. Our work towards VISOR aims to provide a service not designed to fit in a specific cloud offer but rather to overreach sharing and interoperability limitations among different clouds. With VISOR, the management of clouds interoperability can be seamlessly abstracted
from the underlying procedures details. In this way, it aims to provide users with the
ability to manage and expose virtual machine images across heterogeneous clouds, throughout the same generic and centralized repository and management service. VISOR is an open source software with a community-driven development process, thus it can be freely customized and further improved by everyone. The conducted tests to evaluate its performance and resources
usage rate have shown VISOR as a stable and high performance service, even when compared
with other services already in production. Lastly, placing clouds as the main target audience is not a limitation for other use cases. In fact, virtualization and virtual machine images are not exclusively linked to cloud environments. Therefore and given the service agnostic design concerns, it is possible to adapt it to other usage scenarios as well.A Computação em Nuvem (âCloud Computingâ) Ă© um paradigma relativamente novo que visa
cumprir o sonho de fornecer a computação como um serviço. O mesmo surgiu para possibilitar o
fornecimento de recursos de computação (servidores, armazenamento e redes) como um serviço
de acordo com as necessidades dos utilizadores, tornando-os acessĂveis atravĂ©s de protocolos de
Internet comuns. AtravĂ©s das ofertas de âcloudâ, os utilizadores apenas pagam pela quantidade
de recursos que precisam e pelo tempo que os usam. A virtualização é a tecnologia chave
das âcloudsâ, atuando sobre imagens de mĂĄquinas virtuais de forma a gerar mĂĄquinas virtuais
totalmente funcionais. Sendo assim, as imagens de mĂĄquinas virtuais desempenham um papel
fundamental no âCloud Computingâ e a sua gestĂŁo eficiente torna-se um requisito que deve ser
cuidadosamente analisado. Para fazer face a tal necessidade, a maioria das ofertas de âcloudâ
fornece o seu prĂłprio repositĂłrio de imagens, onde as mesmas sĂŁo armazenadas e de onde
sĂŁo copiadas a fim de criar novas mĂĄquinas virtuais. Contudo, com o crescimento do âCloud
Computingâ surgiram novos problemas na gestĂŁo de grandes conjuntos de imagens.
Os repositĂłrios existentes nĂŁo sĂŁo capazes de gerir, armazenar e catalogar images de mĂĄquinas
virtuais de forma eficiente a partir de outras âcloudsâ, mantendo um Ășnico repositĂłrio e serviço
centralizado. Esta necessidade torna-se especialmente importante quando se considera a gestĂŁo
de mĂșltiplas âcloudsâ heterogĂ©neas. Na verdade, apesar da promoção extrema do âCloud Computingâ, ainda existem barreiras Ă sua adoção generalizada. Entre elas, a interoperabilidade
entre âcloudsâ Ă© um dos constrangimentos mais notĂĄveis. As limitaçÔes de interoperabilidade
surgem do fato de as ofertas de âcloudâ atuais possuĂrem interfaces proprietĂĄrias, e de os seus
serviços estarem vinculados às suas próprias necessidades. Os utilizadores enfrentam assim
problemas de compatibilidade e integração difĂceis de gerir, ao lidar com âcloudsâ de diferentes fornecedores. A gestĂŁo e disponibilização de imagens de mĂĄquinas virtuais entre diferentes
âcloudsâ Ă© um exemplo de tais restriçÔes de interoperabilidade.
Esta dissertação apresenta o VISOR, o qual é um repositório e serviço de gestão de imagens de måquinas virtuais genérico. O nosso trabalho em torno do VISOR visa proporcionar um
serviço que nĂŁo foi concebido para lidar com uma âcloudâ especĂfica, mas sim para superar as
limitaçÔes de interoperabilidade entre âcloudsâ. Com o VISOR, a gestĂŁo da interoperabilidade
entre âcloudsâ Ă© abstraĂda dos detalhes subjacentes. Desta forma pretende-se proporcionar
aos utilizadores a capacidade de gerir e expor imagens entre âcloudsâ heterogĂ©neas, mantendo
um repositório e serviço de gestão centralizados. O VISOR é um software de código livre com
um processo de desenvolvimento aberto. O mesmo pode ser livremente personalizado e melhorado por qualquer pessoa. Os testes realizados para avaliar o seu desempenho e a taxa de
utilização de recursos mostraram o VISOR como sendo um serviço eståvel e de alto desempenho,
mesmo quando comparado com outros serviços jĂĄ em utilização. Por fim, colocar as âcloudsâ
como principal pĂșblico-alvo nĂŁo representa uma limitação para outros tipos de utilização. Na
verdade, as imagens de måquinas virtuais e a virtualização não estão exclusivamente ligadas a
ambientes de âcloudâ. Assim sendo, e tendo em conta as preocupaçÔes tidas no desenho de um
serviço genĂ©rico, tambĂ©m Ă© possĂvel adaptar o nosso serviço a outros cenĂĄrios de utilização
Ălypuhelin kotiverkkojen luottamusankkurina
Kun tietoverkot kodeissa monimutkaistuvat, eivÀt kotikÀyttÀjÀt osaa tai halua enÀÀ yllÀpitÀÀ niitÀ. Kotiverkkojen yllÀpito ei eroa nykyisin paljon yritysympÀristöistÀ. KÀyttÀjÀltÀ vaaditaan lÀsnÀolo, tunnukset ja tietÀmys laitteiden operointiin. NÀitÀ vaatimuksia tÀytyy soveltaa, jos yllÀpito ulkoistettaisiin ja pÀÀsy kotiverkkoihin sallittaisiin. Luotettava toimija on palkattava ja jaettava tÀlle tunnistautumiskeino sekÀ pÀÀsy kohdelaitteelle ulkoa kÀsin. TÀmÀ edellyttÀÀ ennakkotoimia ja tunnistautumisavainten jakelua.
KÀyttÀjÀn Àlypuhelimessa toimiva sovellus toimii tÀssÀ luotettuna toimijana. MatkapuhelinliittymÀllÀÀn kÀyttÀjÀ on jo osa luotettua tilaajarekisteriÀ, ja tÀtÀ ominaisuutta kÀytetÀÀn hyvÀksi työssÀ luottamuksen rakentajana. Matkapuhelintunnistuksena kÀytetÀÀn SIM-kortin tilaajatietoa EAP-menetelmÀllÀ. EAP-SIM-pohjaisen tunnistuksen toimivuus esitetÀÀn kÀyttöympÀristössÀ, jossa on simuloitu SIM-kortti ja matkapuhelinoperaattori. Periaatteena on ollut kÀyttÀÀ olemassaolevia tekniikoita yhdistÀen niitÀ uusiin alueisiin, kuten homenet-mÀÀritysten kotiverkkoihin ja edustajalle ulkoistettuun hallintaan. Tunnistus- ja valtuutustietojen vÀlittÀmisen hoitaa WPA2 Enterprise RADIUS-ympÀristössÀ. VÀlttÀÀksemme monimutkaisuutta ja tarpeetonta hienorakeisuutta, kÀytÀmme yksinkertaista hallintaverkkomallia, jonka rajalla on kotiverkosta muuten erillÀÀn oleva Àlypuhelin.
Tuloksena nÀytetÀÀn, ettÀ matkapuhelimella tehty tunnistautuminen luo luottamusankkurin ulkoisen edustajan ja kodin hallintaverkon vÀlille avaten edustajalle hallintayhteyden kotikÀyttÀjÀn valvonnassa. SIM-tunnistuksen hyötyjÀ ovat vahva tunnistus ja laaja kÀyttÀjÀkanta. Haittoina ovat riippuvuus teleoperaattorista, kÀyttÀjÀn identiteetin paljastumisen uhka ja ei-toivottu automaattinen tunnistautuminen.Today, home networks are complex, and the home owners do not necessarily want to administer all aspects of their networks. Configuring home network devices does not differ much from configuring enterprise devices. One needs access, credentials to login and knowledge to operate the device. If the configuration is outsourced to external parties and done remotely, those requirements need adaptation. Access to an end device from the outside must be provided, a trusted operator must be hired, and login credentials shared. For this purpose, some previously set provisioning and distribution of authentication keys is needed.
In this work, an application running on a user's smartphone represents this trusted operator. The fact that the mobile phone subscribers already are part of a reliable infrastructure is used in the study as a trusted base. To benefit from the mobile identification, it is shown how the authentication and authorization are done using an extendable authentication profile (EAP) and a SIM card. A theory to use EAP-SIM authentication at home is presented, and to demonstrate that it works, a simulated testbed is built, tested, and analyzed. The idea is to reuse existing techniques by combining them with such new areas as homenet and delegated management. Authentication claims are transported with WPA2 Enterprise. To further avoid complexity and granularity, we only use a simple model of management network.
As a result, we show that the smartphone authentication provides a trust anchor between a configuration agent and the home network. The home network management can be controlled via the smartphone while keeping the local phone user still in control. The benefits of using the SIM are that it is considered strong, and it has a large existing user base, while its disadvantages include dependency onto the mobile operator. Additionally, there remain challenges in keeping the SIM's identity private and in disabling unwanted re-authentications
Towards Interoperable Research Infrastructures for Environmental and Earth Sciences
This open access book summarises the latest developments on data management in the EU H2020 ENVRIplus project, which brought together more than 20 environmental and Earth science research infrastructures into a single community. It provides readers with a systematic overview of the common challenges faced by research infrastructures and how a âreference model guidedâ engineering approach can be used to achieve greater interoperability among such infrastructures in the environmental and earth sciences. The 20 contributions in this book are structured in 5 parts on the design, development, deployment, operation and use of research infrastructures. Part one provides an overview of the state of the art of research infrastructure and relevant e-Infrastructure technologies, part two discusses the reference model guided engineering approach, the third part presents the software and tools developed for common data management challenges, the fourth part demonstrates the software via several use cases, and the last part discusses the sustainability and future directions
Serviços multimédia multicast de próxima geração
Mestrado em Engenharia ElectrĂłnica e TelecomunicaçÔesUma das mais recentes conquistas na evolução mĂłvel foi o 3G, permitindo o acesso a serviços multimĂ©dia com qualidade de serviço assegurada. No entanto, a tecnologia UMTS, tal como definida na sua Release â99, Ă© apenas capaz de transmitir em modo unicast, sendo manifestamente ineficiente para comunicaçÔes multimĂ©dia almejando grupos de utilizadores.
A tecnologia IMS surge na Release 5 do 3GPP que começou a responder jĂĄ a algumas necessidades, permitindo comunicaçÔes sobre IP oferecendo serviços Internet a qualquer momento e em qualquer lugar sobre tecnologias de comunicação mĂłveis fornecendo pela primeira vez sessĂ”es multimĂ©dia satisfatĂłrias. A Release 6 por sua vez trouxe a tecnologia MBMS que permite transmissĂ”es em broadcast e multicast para redes mĂłveis. O MBMS fornece os serviços de aplicaçÔes multimĂ©dia que todos estavam Ă espera, tanto para os utilizadores como para os prestadores de serviços. O operador pode agora fazer uso da tecnologia existente aumentando todo o tipo de benefĂcios no serviço prestado ao cliente. Com a possĂvel integração destas duas tecnologias passa a ser possĂvel desenvolver serviços assentes em redes convergentes em que os conteĂșdos sĂŁo entregues usando tecnologias unicast, multicast ou broadcast. Neste contexto, o principal motivo deste trabalho consiste essencialmente em fazer uso dos recursos da rede terminando com o desperdĂcio dos mesmos e aumentando a eficiĂȘncia dos serviços atravĂ©s da integração das tecnologias IMS e MBMS.
O trabalho realizado começa com o estudo do estado da arte das telecomunicaçÔes mĂłveis com referĂȘncia Ă s tecnologias referidas, seguindo-se a apresentação da possĂvel integração IMS-MBMS e terminando com o projecto de uma plataforma de demonstração que no futuro possa ser uma implementação de serviço multimĂ©dia multicast. O objectivo principal Ă© mostrar os benefĂcios de um serviço que era normalmente executado em unicast relativamente ao modo multicast, fazendo uso da nova convergĂȘncia de tecnologias IMS e MBMS. Na conclusĂŁo do trabalho sĂŁo referidas as vantagens do uso de portadoras multicast e broadcast, tendo como perspectiva de que este trabalho possa ser um ponto de partida para um novo conjunto de serviços poupando recursos de rede e permitindo uma eficiĂȘncia considerĂĄvel em serviços inovadores.3G is bang up to date in the mobile phone industry. It allows access to multimedia services and gives a guarantee of quality of service. The UMTS technology, defined in 3GPP Release â99, provides an unicast transmission, but it is completely inefficient when it comes to multimedia group communications.
The IMS technology first appeared in Release 5 that has already started to consider the interests of the clients. It provides communications over IP, offering Internet services anytime, anywhere on mobile communication technologies. Also, it offers for the first time satisfactory multimedia sessions. On the other hand, Release 6 gave rise to the MBMS technology that provides broadcast and multicast transmissions for mobile networks. The MBMS provides multimedia applications services that everyone was waiting, including users and service providers. Now the operator makes use of existing technology in order to provide better costumer services. The possible integration of these two technologies will contribute to develop services based on converged networks in which contents are delivered through the unicast, multicast or broadcast technologies. Therefore, the objective of this work is basically to make use of network resources avoiding wastes and improving customer services through the integration of the IMS and the MBMS technologies.
The executed work starts with the mobile telecommunications state of the art with reference to the referred technologies, followed by the IMS-MBMS convergence presentation and finishing with the proposal for implementation of a service platform that can be used for a multimedia multicast service. The main point is to show the benefits of a service that has been normally executed in unicast mode over the multicast mode, making use of the new IMS and MBMS technologies integration. To closure the work it is referred the advantages to use multicast and broadcast bearers, with the perspective that this work could be a starting point to a new set of services, saving network resources and allowing for innovate services a considerable efficency
Hybrid Routing in Delay Tolerant Networks
This work addresses the integration of today\u27s infrastructure-based networks with infrastructure-less networks. The resulting Hybrid Routing System allows for communication over both network types and can help to overcome cost, communication, and overload problems. Mobility aspect resulting from infrastructure-less networks are analyzed and analytical models developed. For development and deployment of the Hybrid Routing System an overlay-based framework is presented
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