184 research outputs found

    Algorithms for advance bandwidth reservation in media production networks

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    Media production generally requires many geographically distributed actors (e.g., production houses, broadcasters, advertisers) to exchange huge amounts of raw video and audio data. Traditional distribution techniques, such as dedicated point-to-point optical links, are highly inefficient in terms of installation time and cost. To improve efficiency, shared media production networks that connect all involved actors over a large geographical area, are currently being deployed. The traffic in such networks is often predictable, as the timing and bandwidth requirements of data transfers are generally known hours or even days in advance. As such, the use of advance bandwidth reservation (AR) can greatly increase resource utilization and cost efficiency. In this paper, we propose an Integer Linear Programming formulation of the bandwidth scheduling problem, which takes into account the specific characteristics of media production networks, is presented. Two novel optimization algorithms based on this model are thoroughly evaluated and compared by means of in-depth simulation results

    Quality assessment technique for ubiquitous software and middleware

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    The new paradigm of computing or information systems is ubiquitous computing systems. The technology-oriented issues of ubiquitous computing systems have made researchers pay much attention to the feasibility study of the technologies rather than building quality assurance indices or guidelines. In this context, measuring quality is the key to developing high-quality ubiquitous computing products. For this reason, various quality models have been defined, adopted and enhanced over the years, for example, the need for one recognised standard quality model (ISO/IEC 9126) is the result of a consensus for a software quality model on three levels: characteristics, sub-characteristics, and metrics. However, it is very much unlikely that this scheme will be directly applicable to ubiquitous computing environments which are considerably different to conventional software, trailing a big concern which is being given to reformulate existing methods, and especially to elaborate new assessment techniques for ubiquitous computing environments. This paper selects appropriate quality characteristics for the ubiquitous computing environment, which can be used as the quality target for both ubiquitous computing product evaluation processes ad development processes. Further, each of the quality characteristics has been expanded with evaluation questions and metrics, in some cases with measures. In addition, this quality model has been applied to the industrial setting of the ubiquitous computing environment. These have revealed that while the approach was sound, there are some parts to be more developed in the future

    ENHANCED HOST DISCOVERY IN SDN/FABRIC-BASED NETWORKS

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    Various solutions are provided herein to facilitate the efficient discovery of hosts in large network environments, such as software-defined networking (SDN) or fabric-based networks, utilizing several techniques. A first technique supports the ability to efficiently manage silent ports and silent media access control (MAC) addresses. This technique involves applying a novel heuristic to ports and MAC addresses, classifying such entities (as silent, quiet, and noisy), and intelligently polling such entities. A second technique supports a Multicast Listener Discovery (MLD)-based host discovery approach that is applicable to Internet Protocol (IP) version 4 (IPv4) and involves a host creating an IP version 6 (IPv6) address that embeds its IPv4 address, the addition of a well-known first byte to the three bytes in a Solicited-Node multicast address (SNMA), and the use of a form of unicast ping to confirm whether a host formed a derived address. A third technique involves using a service lookup for deterministic host discovery that involves the use of upper-layer discovery services to cause a host to expose its addresses in the replies to multicast discoveries

    Off the Shelf Cloud Robotics for the Smart Home: Empowering a Wireless Robot through Cloud Computing

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    In this paper, we explore the possibilities offered by the integration of home automation systems and service robots. In particular, we examine how advanced computationally expensive services can be provided by using a cloud computing approach to overcome the limitations of the hardware available at the user’s home. To this end, we integrate two wireless low-cost, off-the-shelf systems in this work, namely, the service robot Rovio and the home automation system Z-wave. Cloud computing is used to enhance the capabilities of these systems so that advanced sensing and interaction services based on image processing and voice recognition can be offered.Ministerio de Economía TEC2016-80242-PJunta de Andalucía P11-TEP-812

    Service Oriented Computing Imperatives in Ad Hoc Wireless Settings

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    Service oriented computing is a new paradigm that is gaining popularity in dis-tributed computing environments due to its emphasis on highly specialized, modular and platform-agnostic code facilitating interoperability of systems. It borrows concepts from more mature paradigms such as object-oriented and component computing. This results in a progression from object-oriented computing to component computing and finally to service oriented computing, a new paradigm for designing and delivering software. Just as an object encapsulates state and behavior at a fine level of granularity, a service offers similar encapsulation at a larger scale. This evolution raises the level of abstraction at which systems are engineered, while preserving beneficial properties such as modularity, substitution and encapsulation. Every participant in a service oriented computing system is a provider or user of a service, or both. The service oriented computing paradigm is characterized by a minimalist philosophy, in that a user needs to carry only a small amount of code in its local storage, and exploits other services by discovering and using their capabilities to complete its assigned task. This chapter is the result of our experiences with designing and building service oriented computing frameworks for ad hoc wireless networks (Handorean & Roman, 2002). It examines the salient imperatives required to deliver a service oriented computing frame-work for ad hoc wireless networks. Ad hoc wireless networks are collections of hosts capable of wireless communication. Hosts within proximity of each other opportunistically form a network which changes due to host mobility. An ad hoc wireless network is a dynamic environment by necessity, which exhibits transient interactions, decoupled computing, physical mobility of hosts, and logical mobility of code. The network infrastructure is supported by the participating hosts themselves and there is no dependence on external, fixed resources. Ad hoc wireless environments are especially challenging to program when compared against other classes of fixed wireless environments because of the implications of mobility, i.e., frequent disconnections and inherent dynamism of the network on program execution. An important class of ad hoc mobile systems is based on small, portable devices, and this class of systems is the focus of this chapter. Such devices have limited storage capacity and battery power, which restricts the number of programs they can store and run locally. Service oriented computing offers a solution to this problem. By its very nature, service oriented computing is designed to facilitate sharing of capabilities while minimizing the amount of functionality a single host needs to maintain. Such a design is especially effective in ad hoc networks where storage space on individual hosts is at a premium, yet where the open environment allows a large number of hosts to contribute small functions resulting in a rich set of capabilities being available in the network as a whole. Service oriented computing has received much attention from researchers worldwide. However, most of this work has been focused on architectures and implementations for wired networks. Migrating service oriented computing to ad hoc networks is non-trivial and requires a systematic rethinking of core concepts. Many lessons have been learned from the work done in the wired setting, especially regarding description and matching of services. However, the more demanding environment of an ad hoc wireless network requires novel approaches to advertising, discovering and invoking services. We envision such ad hoc networks being used in a range of application domains, such as response coordination by firemen and police at disaster sites, or command and control of military units in a battlefield. Such scenarios demand reliability despite the dynamic nature of the underlying network. The motivation for this chapter is to understand the unique imperatives for a viable service oriented computing framework in ad hoc wireless settings, and to illustrate selected solution strategies. We begin by examining current technologies, algorithms and capabilities that have been implemented for use in wired networks as a baseline. We then extend these concepts to cater to the special challenges of service oriented computing in ad hoc networks and direct the reader’s attention to research issues in this area, presenting some of our own contributions in the process. The rest of the chapter is organized as follows. We describe existing service oriented computing architectures and the Semantic Web effort in the Background section. The section on Ad Hoc Wireless Network Perspective on Service Oriented Computing represents the main thrust of this chapter and discusses the elements of a service oriented computing framework, examining current technologies alongside our ideas on how these concepts may be applied to ad hoc networks. We cover potential areas of research in the Future Trends section. Finally, we summarize our findings in the Conclusion section

    Greenpass Client Tools for Delegated Authorization in Wireless Networks

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    Dartmouth\u27s Greenpass project seeks to provide strong access control to a wireless network while simultaneously providing flexible guest access; to do so, it augments the Wi-Fi Alliance\u27s existing WPA standard, which offers sufficiently strong user authentication and access control, with authorization based on SPKI certificates. SPKI allows certain local users to delegate network access to guests by issuing certificates that state, in essence, he should get access because I said it\u27s okay. The Greenpass RADIUS server described in Kim\u27s thesis [55] performs an authorization check based on such statements so that guests can obtain network access without requiring a busy network administrator to set up new accounts in a centralized database. To our knowledge, Greenpass is the first working delegation-based solution to Wi-Fi access control. My thesis describes the Greenpass client tools, which allow a guest to introduce himself to a delegator and allow the delegator to issue a new SPKI certificate to the guest. The guest does not need custom client software to introduce himself or to connect to the Wi-Fi network. The guest and delegator communicate using a set of Web applications. The guest obtains a temporary key pair and X.509 certificate if needed, then sends his public key value to a Web server we provide. The delegator looks up her guest\u27s public key and runs a Java applet that lets her verify her guests\u27 identity using visual hashing and issue a new SPKI certificate to him. The guest\u27s new certificate chain is stored as an HTTP cookie to enable him to push it to an authorization server at a later time. I also describe how Greenpass can be extended to control access to a virtual private network (VPN) and suggest several interesting future research and development directions that could build on this work.My thesis describes the Greenpass client tools, which allow a guest to introduce himself to a delegator and allow the delegator to issue a new SPKI certificate to the guest. The guest does not need custom client software to introduce himself or to connect to the Wi-Fi network. The guest and delegator communicate using a set of Web applications. The guest obtains a temporary key pair and X.509 certificate if needed, then sends his public key value to a Web server we provide. The delegator looks up her guest\u27s public key and runs a Java applet that lets her verify her guests\u27 identity using visual hashing and issue a new SPKI certificate to him. The guest\u27s new certificate chain is stored as an HTTP cookie to enable him to push it to an authorization server at a later time. I also describe how Greenpass can be extended to control access to a virtual private network (VPN) and suggest several interesting future research and development directions that could build on this work

    NMI: Exploration of middleware technologies for ubiquitous computing with applications to grid computing

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    Issued as final reportNational Science Foundation (U.S.

    Plug-and-Participate for Limited Devices in the Field of Industrial Automation

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    Ausgangspunkt und gleichzeitig Motivation dieser Arbeit ist die heutige Marktsituation: Starke Kundenbedürfnisse nach individuellen Gütern stehen oftmals eher auf Massenproduktion ausgerichteten Planungs- und Automatisierungssystemen gegenüber - die Befriedigung individueller Kundenbedürfnisse setzt aber Flexibilität und Anpassungsfähigkeit voraus. Ziel dieser Arbeit ist es daher, einen Beitrag zu leisten, der es Unternehmen ermöglichen soll, auf diese individuellen Bedürfnisse flexibel reagieren zu können. Hierbei kann es im Rahmen der Dissertation natürlich nicht um eine Revolutionierung der gesamten Automatisierungs- und Planungslandschaft gehen; vielmehr ist die Lösung, die der Autor der Arbeit präsentiert, ein integraler Bestandteil eines Automatisierungskonzeptes, das im Rahmen des PABADIS Projektes entwickelt wurde: Während PABADIS das gesamte Spektrum von Planung und Maschineninfrastruktur zum Inhalt hat, bezieht sich der Kern dieser Arbeit weitestgehend auf den letztgenannten Punkt - Maschineninfrastruktur. Ziel war es, generische Maschinenfunktionalität in einem Netzwerk anzubieten, durch das Fertigungsaufträge selbstständig navigieren. Als Lösung präsentiert diese Dissertation ein Plug-and-Participate basiertes Konzept, welches beliebige Automatisierungsfunktionen in einer spontanen Gemeinschaft bereitstellt. Basis ist ein generisches Interface, in dem die generellen Anforderungen solcher ad-hoc Infrastrukturen aggregiert sind. Die Implementierung dieses Interfaces in der PABADIS Referenzimplementierung sowie die Gegenüberstellung der Systemanforderungen und Systemvoraussetzungen zeigte, das klassische Plug-and-Participate Technologien wie Jini und UPnP aufgrund ihrer Anforderungen nicht geeignet sind - Automatisierungsgeräte stellen oftmals nur eingeschränkte Ressourcen bereit. Daher wurde als zweites Ergebnis neben dem Plug-and-Participate basierten Automatisierungskonzept eine Plug-and-Participate Technologie entwickelt - Pini - die den Gegebenheiten der Automatisierungswelt gerecht wird und schließlich eine Anwendung von PABADIS auf heutigen Automatisierungsanlagen erlaubt. Grundlegende Konzepte von Pini, die dies ermöglichen, sind die gesamte Grundarchitektur auf Basis eines verteilten Lookup Service, die Art und Weise der Dienstrepräsentation sowie die effiziente Nutzung der angebotenen Dienste. Mit Pini und darauf aufbauenden Konzepten wie PLAP ist es nun insbesondere möglich, Automatisierungssysteme wie PABADIS auf heutigen Anlagen zu realisieren. Das wiederum ist ein Schritt in Richtung Kundenorientierung - solche Systeme sind mit Hinblick auf Flexibilität und Anpassungsfähigkeit gestaltet worden, um Kundenbedürfnissen effizient gerecht zu werden
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