2,263 research outputs found

    Cloud Computing in VANETs: Architecture, Taxonomy, and Challenges

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    Cloud Computing in VANETs (CC-V) has been investigated into two major themes of research including Vehicular Cloud Computing (VCC) and Vehicle using Cloud (VuC). VCC is the realization of autonomous cloud among vehicles to share their abundant resources. VuC is the efficient usage of conventional cloud by on-road vehicles via a reliable Internet connection. Recently, number of advancements have been made to address the issues and challenges in VCC and VuC. This paper qualitatively reviews CC-V with the emphasis on layered architecture, network component, taxonomy, and future challenges. Specifically, a four-layered architecture for CC-V is proposed including perception, co-ordination, artificial intelligence and smart application layers. Three network component of CC-V namely, vehicle, connection and computation are explored with their cooperative roles. A taxonomy for CC-V is presented considering major themes of research in the area including design of architecture, data dissemination, security, and applications. Related literature on each theme are critically investigated with comparative assessment of recent advances. Finally, some open research challenges are identified as future issues. The challenges are the outcome of the critical and qualitative assessment of literature on CC-V

    Steps towards adaptive situation and context-aware access: a contribution to the extension of access control mechanisms within pervasive information systems

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    L'Ă©volution des systĂšmes pervasives a ouvert de nouveaux horizons aux systĂšmes d'information classiques qui ont intĂ©grĂ© des nouvelles technologies et des services qui assurent la transparence d'accĂšs aux resources d'information Ă  n'importe quand, n'importe oĂč et n'importe comment. En mĂȘme temps, cette Ă©volution a relevĂ© des nouveaux dĂ©fis Ă  la sĂ©curitĂ© de donnĂ©es et Ă  la modĂ©lisation du contrĂŽle d'accĂšs. Afin de confronter ces challenges, differents travaux de recherche se sont dirigĂ©s vers l'extension des modĂšles de contrĂŽles d'accĂšs (en particulier le modĂšle RBAC) afin de prendre en compte la sensibilitĂ© au contexte dans le processus de prise de dĂ©cision. Mais la liaison d'une dĂ©cision d'accĂšs aux contraintes contextuelles dynamiques d'un utilisateur mobile va non seulement ajouter plus de complexitĂ© au processus de prise de dĂ©cision mais pourra aussi augmenter les possibilitĂ©s de refus d'accĂšs. Sachant que l'accessibilitĂ© est un Ă©lĂ©ment clĂ© dans les systĂšmes pervasifs et prenant en compte l'importance d'assurer l'accĂ©ssibilitĂ© en situations du temps rĂ©el, nombreux travaux de recherche ont proposĂ© d'appliquer des mĂ©canismes flexibles de contrĂŽle d'accĂšs avec des solutions parfois extrĂȘmes qui depassent les frontiĂšres de sĂ©curitĂ© telle que l'option de "Bris-de-Glace". Dans cette thĂšse, nous introduisons une solution modĂ©rĂ©e qui se positionne entre la rigiditĂ© des modĂšles de contrĂŽle d'accĂšs et la flexibilitĂ© qui expose des risques appliquĂ©es pendant des situations du temps rĂ©el. Notre contribution comprend deux volets : au niveau de conception, nous proposons PS-RBAC - un modĂšle RBAC sensible au contexte et Ă  la situation. Le modĂšle rĂ©alise des attributions des permissions adaptatives et de solution de rechange Ă  base de prise de dĂ©cision basĂ©e sur la similaritĂ© face Ă  une situation importanteÀ la phase d'exĂ©cution, nous introduisons PSQRS - un systĂšme de rĂ©Ă©criture des requĂȘtes sensible au contexte et Ă  la situation et qui confronte les refus d'accĂšs en reformulant la requĂȘte XACML de l'utilisateur et en lui proposant une liste des resources alternatives similaires qu'il peut accĂ©der. L'objectif est de fournir un niveau de sĂ©curitĂ© adaptative qui rĂ©pond aux besoins de l'utilisateur tout en prenant en compte son rĂŽle, ses contraintes contextuelles (localisation, rĂ©seau, dispositif, etc.) et sa situation. Notre proposition a Ă©tĂ© validĂ© dans trois domaines d'application qui sont riches des contextes pervasifs et des scĂ©narii du temps rĂ©el: (i) les Équipes Mobiles GĂ©riatriques, (ii) les systĂšmes avioniques et (iii) les systĂšmes de vidĂ©o surveillance.The evolution of pervasive computing has opened new horizons to classical information systems by integrating new technologies and services that enable seamless access to information sources at anytime, anyhow and anywhere. Meanwhile this evolution has opened new threats to information security and new challenges to access control modeling. In order to meet these challenges, many research works went towards extending traditional access control models (especially the RBAC model) in order to add context awareness within the decision-making process. Meanwhile, tying access decisions to the dynamic contextual constraints of mobile users would not only add more complexity to decision-making but could also increase the possibilities of access denial. Knowing that accessibility is a key feature for pervasive systems and taking into account the importance of providing access within real-time situations, many research works have proposed applying flexible access control mechanisms with sometimes extreme solutions that depass security boundaries such as the Break-Glass option. In this thesis, we introduce a moderate solution that stands between the rigidity of access control models and the riskful flexibility applied during real-time situations. Our contribution is twofold: on the design phase, we propose PS-RBAC - a Pervasive Situation-aware RBAC model that realizes adaptive permission assignments and alternative-based decision-making based on similarity when facing an important situation. On the implementation phase, we introduce PSQRS - a Pervasive Situation-aware Query Rewriting System architecture that confronts access denials by reformulating the user's XACML access request and proposing to him a list of alternative similar solutions that he can access. The objective is to provide a level of adaptive security that would meet the user needs while taking into consideration his role, contextual constraints (location, network, device, etc.) and his situation. Our proposal has been validated in three application domains that are rich in pervasive contexts and real-time scenarios: (i) Mobile Geriatric Teams, (ii) Avionic Systems and (iii) Video Surveillance Systems

    A survey of self organisation in future cellular networks

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    This article surveys the literature over the period of the last decade on the emerging field of self organisation as applied to wireless cellular communication networks. Self organisation has been extensively studied and applied in adhoc networks, wireless sensor networks and autonomic computer networks; however in the context of wireless cellular networks, this is the first attempt to put in perspective the various efforts in form of a tutorial/survey. We provide a comprehensive survey of the existing literature, projects and standards in self organising cellular networks. Additionally, we also aim to present a clear understanding of this active research area, identifying a clear taxonomy and guidelines for design of self organising mechanisms. We compare strength and weakness of existing solutions and highlight the key research areas for further development. This paper serves as a guide and a starting point for anyone willing to delve into research on self organisation in wireless cellular communication networks

    Design and implementation of high speed multimedia network.

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    by Yeung Chung Toa.Thesis (M.Phil.)--Chinese University of Hong Kong, 1994.Includes bibliographical references (leaves 63-[65]).Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Bandwidth required by multimedia applications --- p.1Chapter 1.2 --- Real-time requirement --- p.2Chapter 1.3 --- Multicasting --- p.2Chapter 1.4 --- Other networks --- p.3Chapter 1.5 --- Overview of CUM LAUDE NET --- p.5Chapter 1.5.1 --- Protocols --- p.7Chapter 1.5.2 --- Network Services --- p.8Chapter 1.6 --- Scope of the Thesis --- p.9Chapter 2 --- Network Architecture --- p.11Chapter 2.1 --- CUM LAUDE NET Architectural Overview --- p.11Chapter 2.2 --- Level One Network Architecture --- p.12Chapter 2.3 --- Level-One Router --- p.14Chapter 2.3.1 --- packet forwarding --- p.14Chapter 2.3.2 --- packet insertion --- p.15Chapter 2.3.3 --- packet removal --- p.15Chapter 2.3.4 --- fault protection --- p.15Chapter 2.4 --- Hub --- p.16Chapter 2.5 --- Host & Network Interface Card --- p.17Chapter 3 --- Protocol --- p.19Chapter 3.1 --- Design Overview --- p.19Chapter 3.2 --- Layering --- p.20Chapter 3.3 --- "Segment, Datagram, and Packet Format" --- p.21Chapter 3.3.1 --- IP/VCI field --- p.23Chapter 3.4 --- Data Link --- p.23Chapter 3.4.1 --- byte format and data link synchronization --- p.23Chapter 3.4.2 --- access control byte --- p.24Chapter 3.4.3 --- packet/frame boundary --- p.26Chapter 3.5 --- Fast Packet Routing Protocol --- p.26Chapter 3.5.1 --- Level-2/Level-l Bridge/Router --- p.27Chapter 3.5.2 --- Level-1 Hub --- p.29Chapter 3.5.3 --- Local Host NIC --- p.29Chapter 3.6 --- Media Access Control Protocol I : ACTA --- p.30Chapter 3.7 --- Media Access Control Protocol II: Hub Polling --- p.34Chapter 3.8 --- Protocol Implementation on CUM LAUDE NET --- p.36Chapter 4 --- Hardware Implementation & Performance of Routers and NIC --- p.40Chapter 4.1 --- Functionality of Router --- p.40Chapter 4.2 --- Important Components Used in the Router Design --- p.43Chapter 4.2.1 --- TAXI Transmitter and Receiver --- p.43Chapter 4.2.2 --- First-In-First-Out Memory (FIFO) --- p.44Chapter 4.3 --- Design of Router --- p.45Chapter 4.3.1 --- Version 1 --- p.45Chapter 4.3.2 --- Version 2 --- p.47Chapter 4.3.3 --- Version 3 --- p.50Chapter 4.4 --- Lessons Learned from the High Speed Router Design --- p.57Chapter 5 --- Conclusion --- p.61Bibliography --- p.6

    Real-Time QoS-Aware Vehicle Tracking: An Experimental and Comparative Study

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    AbstractRecently, web service became popular for Real-time Communication (RTC). It allows bi-directional, real-time communication between web clients and server. On the other hand, Data Distribution Service (DDS) middleware offers unified integration with high-performance due to its scalability, flexibility, real-time, mission-critical networks and rich QoS features. DDS is based on the publish/subscribe communication model. It improves RTC through its efficient and high-performance data delivery mechanism. This paper studies and investigates that how DDS is better for RTC. Experimental studies are conducted to compare text messaging using socket IO over DDS Web API. The result concerns the throughput satisfaction rate, round trip time and packet loss. In addition, we consider some of QoS of DDS during experimental work e.g. deadline, time based filter etc

    Intelligent Reconfigurable Integrated Satellite Processor

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    We present our Intelligent Reconfigurable Integrated Satellite (IRIS) Processor. At the heart of the system are our reconfigurable vision chips which are capable of massively parallel analog processing. The smart vision chips are capable of not only centroiding and pattern recognition but also tracking and controlling devices including MEMs devices and active pixel arrays. In addition to discussing the active optic and active electronic devices, several small satellite system applications are presented along with experimental and simulation results

    Preliminary specification and design documentation for software components to achieve catallaxy in computational systems

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    This Report is about the preliminary specifications and design documentation for software components to achieve Catallaxy in computational systems. -- Die Arbeit beschreibt die Spezifikation und das Design von Softwarekomponenten, um das Konzept der Katallaxie in Grid Systemen umzusetzen. Eine EinfĂŒhrung ordnet das Konzept der Katallaxie in bestehende Grid Taxonomien ein und stellt grundlegende Komponenten vor. Anschließend werden diese Komponenten auf ihre Anwendbarkeit in bestehenden Application Layer Netzwerken untersucht.Grid Computing

    Economic Policy Analysis and the Internet: Coming to Terms with a Telecommunications Anomaly

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    The significant set of public policy issues for economic analysis that arise from the tensions between the ‘special benefits’ of the Internet as a platform for innovation, and the drawbacks of the “anomalous” features of the Internet viewed as simply one among the array of telecommunications systems, is the focus of discussion in this chapter. Economists concerned with industrial organization and regulation (including antitrust and merger law) initially found new scope for application of their expertise in conventional policy analyses of the Internet’s interactions with other segments of the telecommunications sector (broadcast and cable television, radio and telephone), and emphasized the potential congestion problems posed by user anonymity and flat rate pricing. Policy issues of a more dynamic kind have subsequently come to the fore. These involve classic tradeoffs between greater efficiency and producer and consumer surpluses today, and a potential for more innovation in Web-based products and service in the future. Many such tradeoffs involve choices such as that between policies that would preserve the original ‘end-to-end’ design of the original Internet architecture, and those that would be more encouraging of market-driven deployment of new technologies that afforded ISPs with greater market power the opportunity to offer (and extract greater profits from) restricted-Web services that consumers valued highly, such as secure and private VOIP.public policy, telecommunications, Web-based products, user anonymity
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