4,955 research outputs found

    EVEREST IST - 2002 - 00185 : D23 : final report

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    Deliverable pĂșblic del projecte europeu EVERESTThis deliverable constitutes the final report of the project IST-2002-001858 EVEREST. After its successful completion, the project presents this document that firstly summarizes the context, goal and the approach objective of the project. Then it presents a concise summary of the major goals and results, as well as highlights the most valuable lessons derived form the project work. A list of deliverables and publications is included in the annex.Postprint (published version

    Preventing Distributed Denial-of-Service Attacks on the IMS Emergency Services Support through Adaptive Firewall Pinholing

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    Emergency services are vital services that Next Generation Networks (NGNs) have to provide. As the IP Multimedia Subsystem (IMS) is in the heart of NGNs, 3GPP has carried the burden of specifying a standardized IMS-based emergency services framework. Unfortunately, like any other IP-based standards, the IMS-based emergency service framework is prone to Distributed Denial of Service (DDoS) attacks. We propose in this work, a simple but efficient solution that can prevent certain types of such attacks by creating firewall pinholes that regular clients will surely be able to pass in contrast to the attackers clients. Our solution was implemented, tested in an appropriate testbed, and its efficiency was proven.Comment: 17 Pages, IJNGN Journa

    Adaptive Video Streaming Testbed Design for Performance Study and Assessment of QoE

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    [EN] Hypertext Transfer Protocol adaptive streaming switches between different video qualities, adapting to the network conditions, and avoids stalling streamed frames over highÂżoscillation client's throughput improving the users' quality of experience (QoE). Quality of experience has become the most important parameter to lead the service providers to know about the endÂżuser feedback. Implementing Hypertext Transfer Protocol adaptive streaming applications to find out QoE in realÂżlife scenarios of vast networks becomes more challenging and complex task regarding to cost, agile, time, and decisions. In this paper, a virtualized network testbed to virtualize various machines to support implementing experiments of adaptive video streaming has been developed. Within the test study, the metrics which demonstrate performance of QoE are investigated, respectively, including initial delay (ie, startup delay at the beginning of playback a video), frequency switches (ie, number of times the quality is changed), accumulative video time (ie, number and length of stalls), CPU usage, and battery energy consumption. Furthermore, the relation between effective parameters of QoS on the aforementioned metrics for different segment length is investigated. Experimental results show that the proposed virtualized system is agile, easy to install and use, and costs less than real testbeds. Moreover, the subjective and objective performance studies of QoE evaluation in the system have proven that the segment lengths of 6 to 8 seconds were faired and more efficient than others according to the investigated parameters.Ministerio de Economia y Competitividad, Grant/Award Number: TIN2014-57991-C3-1-PAbdullah, MTA.; Lloret, J.; Ali, A.; GarcĂ­a-GarcĂ­a, L. (2018). Adaptive Video Streaming Testbed Design for Performance Study and Assessment of QoE. International Journal of Communication Systems. 1-15. https://doi.org/10.1002/dac.3551S11

    Telescience testbed pilot program

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    The Universities Space Research Association (USRA), under sponsorship from the NASA Office of Space Science and Applications, is conducting a Telescience Testbed Pilot Program. Fifteen universities, under subcontract to USRA, are conducting a variety of scientific experiments using advanced technology to determine the requirements and evaluate the tradeoffs for the information system of the Space Station era. An interim set of recommendations based on the experiences of the first six months of the pilot program is presented

    Design of an emulation framework for evaluating large-scale open content aware networks

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    The popularity of multimedia services has resulted in new revenue opportunities for network and service providers but has also introduced important new challenges. The large amount of resources and stringent quality requirements imposed by multimedia services has triggered the need for open content aware networks, where specific management algorithms that optimize the delivery of multimedia services can be dynamically plugged in when required. In the past, a plethora of algorithms have been proposed ranging from specific cache algorithms to video client heuristics that are optimized for a specific multimedia service type and its corresponding delivery. However, it remains difficult to accurately characterize the performance of these algorithms and investigate the impact of an actual deployment in multimedia services. In this paper, we present a framework that allows evaluating the performance of such algorithms for open content aware networks. The proposed evaluation framework has two important advantages. First, it performs an emulation of the novel algorithms instead of using a simulation approach, which is often carried out to characterize performance. Second, the emulation framework allows evaluating the impact of combining different multimedia algorithms with each other. We present the architecture of the emulation framework and discuss the main software components used. Furthermore, we present a performance evaluation of an illustrative use case, which identifies the need for emulation-based evaluation

    Using programmable network management techniques to establish experimental networking testbeds

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    Performance Evaluation of UDSM Network to Deliver Multimedia eLearning Contents: Case of CoICT

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    The use of technology in education in Sub-Saharan Africa has been reported to be hindered by many factors including inadequate Information and Communication Technology (ICT) infrastructure, low internet speed, and lack of skills to use educational technologies. This paper aim at evaluating how the available ICT infrastructure at the College of Information and Communication Technologies (CoICT) can support, with acceptable Quality of Service (QoS), the delivery of multimedia applications for eLearning services. The evaluation was performed over a network testbed implemented in a computer laboratory for wired and wireless connections. The testbed consisted of five personal computers (PCs) connected via a switch and a router to the internet for the wired connection. The wireless connection consisted of three PCs and a laptop connected through a switch and a router to the internet via a wireless access point. Four different multimedia applications were run through the PCs, and traffic data was mirrored and captured at one of the PC using Wireshark network analyzer. The traffic included streamed and conversational video and audio using YouTube and Zoom applications, respectively; interactive web browsing using web browsers; bulk file transfer, and a mixture of all applications running on the computers. Traffic data captured during the running of these applications were packet loss, delay, jitter, and throughput. The QoS performance parameters obtained were within the acceptable threshold values as per International Telecommunication Union, Telecommunication Standardization Sector (ITU-T) values. Results revealed that ICT infrastructure at CoICT can support delivery of multimedia content for eLearning purposes for both wired and wireless connections. Having the infrastructure capable of supporting multimedia applications with the acceptable QoS implies that instructors are equipped with a conducive environment that supports multimedia application. Hence, they are expected to use and continue using educational technologies to facilitate teaching and learning processe

    Understanding user experience of mobile video: Framework, measurement, and optimization

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    Since users have become the focus of product/service design in last decade, the term User eXperience (UX) has been frequently used in the field of Human-Computer-Interaction (HCI). Research on UX facilitates a better understanding of the various aspects of the user’s interaction with the product or service. Mobile video, as a new and promising service and research field, has attracted great attention. Due to the significance of UX in the success of mobile video (Jordan, 2002), many researchers have centered on this area, examining users’ expectations, motivations, requirements, and usage context. As a result, many influencing factors have been explored (Buchinger, Kriglstein, Brandt & Hlavacs, 2011; Buchinger, Kriglstein & Hlavacs, 2009). However, a general framework for specific mobile video service is lacking for structuring such a great number of factors. To measure user experience of multimedia services such as mobile video, quality of experience (QoE) has recently become a prominent concept. In contrast to the traditionally used concept quality of service (QoS), QoE not only involves objectively measuring the delivered service but also takes into account user’s needs and desires when using the service, emphasizing the user’s overall acceptability on the service. Many QoE metrics are able to estimate the user perceived quality or acceptability of mobile video, but may be not enough accurate for the overall UX prediction due to the complexity of UX. Only a few frameworks of QoE have addressed more aspects of UX for mobile multimedia applications but need be transformed into practical measures. The challenge of optimizing UX remains adaptations to the resource constrains (e.g., network conditions, mobile device capabilities, and heterogeneous usage contexts) as well as meeting complicated user requirements (e.g., usage purposes and personal preferences). In this chapter, we investigate the existing important UX frameworks, compare their similarities and discuss some important features that fit in the mobile video service. Based on the previous research, we propose a simple UX framework for mobile video application by mapping a variety of influencing factors of UX upon a typical mobile video delivery system. Each component and its factors are explored with comprehensive literature reviews. The proposed framework may benefit in user-centred design of mobile video through taking a complete consideration of UX influences and in improvement of mobile videoservice quality by adjusting the values of certain factors to produce a positive user experience. It may also facilitate relative research in the way of locating important issues to study, clarifying research scopes, and setting up proper study procedures. We then review a great deal of research on UX measurement, including QoE metrics and QoE frameworks of mobile multimedia. Finally, we discuss how to achieve an optimal quality of user experience by focusing on the issues of various aspects of UX of mobile video. In the conclusion, we suggest some open issues for future study
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