262 research outputs found

    TechNews digests: Jan - Nov 2005

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    TechNews is a technology, news and analysis service aimed at anyone in the education sector keen to stay informed about technology developments, trends and issues. TechNews focuses on emerging technologies and other technology news. TechNews service : digests september 2004 till May 2010 Analysis pieces and News combined publish every 2 to 3 month

    Systems and Methods for Measuring and Improving End-User Application Performance on Mobile Devices

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    In today's rapidly growing smartphone society, the time users are spending on their smartphones is continuing to grow and mobile applications are becoming the primary medium for providing services and content to users. With such fast paced growth in smart-phone usage, cellular carriers and internet service providers continuously upgrade their infrastructure to the latest technologies and expand their capacities to improve the performance and reliability of their network and to satisfy exploding user demand for mobile data. On the other side of the spectrum, content providers and e-commerce companies adopt the latest protocols and techniques to provide smooth and feature-rich user experiences on their applications. To ensure a good quality of experience, monitoring how applications perform on users' devices is necessary. Often, network and content providers lack such visibility into the end-user application performance. In this dissertation, we demonstrate that having visibility into the end-user perceived performance, through system design for efficient and coordinated active and passive measurements of end-user application and network performance, is crucial for detecting, diagnosing, and addressing performance problems on mobile devices. My dissertation consists of three projects to support this statement. First, to provide such continuous monitoring on smartphones with constrained resources that operate in such a highly dynamic mobile environment, we devise efficient, adaptive, and coordinated systems, as a platform, for active and passive measurements of end-user performance. Second, using this platform and other passive data collection techniques, we conduct an in-depth user trial of mobile multipath to understand how Multipath TCP (MPTCP) performs in practice. Our measurement study reveals several limitations of MPTCP. Based on the insights gained from our measurement study, we propose two different schemes to address the identified limitations of MPTCP. Last, we show how to provide visibility into the end- user application performance for internet providers and in particular home WiFi routers by passively monitoring users' traffic and utilizing per-app models mapping various network quality of service (QoS) metrics to the application performance.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/146014/1/ashnik_1.pd

    Quality of experience and access network traffic management of HTTP adaptive video streaming

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    The thesis focuses on Quality of Experience (QoE) of HTTP adaptive video streaming (HAS) and traffic management in access networks to improve the QoE of HAS. First, the QoE impact of adaptation parameters and time on layer was investigated with subjective crowdsourcing studies. The results were used to compute a QoE-optimal adaptation strategy for given video and network conditions. This allows video service providers to develop and benchmark improved adaptation logics for HAS. Furthermore, the thesis investigated concepts to monitor video QoE on application and network layer, which can be used by network providers in the QoE-aware traffic management cycle. Moreover, an analytic and simulative performance evaluation of QoE-aware traffic management on a bottleneck link was conducted. Finally, the thesis investigated socially-aware traffic management for HAS via Wi-Fi offloading of mobile HAS flows. A model for the distribution of public Wi-Fi hotspots and a platform for socially-aware traffic management on private home routers was presented. A simulative performance evaluation investigated the impact of Wi-Fi offloading on the QoE and energy consumption of mobile HAS.Die Doktorarbeit beschäftigt sich mit Quality of Experience (QoE) – der subjektiv empfundenen Dienstgüte – von adaptivem HTTP Videostreaming (HAS) und mit Verkehrsmanagement, das in Zugangsnetzwerken eingesetzt werden kann, um die QoE des adaptiven Videostreamings zu verbessern. Zuerst wurde der Einfluss von Adaptionsparameters und der Zeit pro Qualitätsstufe auf die QoE von adaptivem Videostreaming mittels subjektiver Crowdsourcingstudien untersucht. Die Ergebnisse wurden benutzt, um die QoE-optimale Adaptionsstrategie für gegebene Videos und Netzwerkbedingungen zu berechnen. Dies ermöglicht Dienstanbietern von Videostreaming verbesserte Adaptionsstrategien für adaptives Videostreaming zu entwerfen und zu benchmarken. Weiterhin untersuchte die Arbeit Konzepte zum Überwachen von QoE von Videostreaming in der Applikation und im Netzwerk, die von Netzwerkbetreibern im Kreislauf des QoE-bewussten Verkehrsmanagements eingesetzt werden können. Außerdem wurde eine analytische und simulative Leistungsbewertung von QoE-bewusstem Verkehrsmanagement auf einer Engpassverbindung durchgeführt. Schließlich untersuchte diese Arbeit sozialbewusstes Verkehrsmanagement für adaptives Videostreaming mittels WLAN Offloading, also dem Auslagern von mobilen Videoflüssen über WLAN Netzwerke. Es wurde ein Modell für die Verteilung von öffentlichen WLAN Zugangspunkte und eine Plattform für sozialbewusstes Verkehrsmanagement auf privaten, häuslichen WLAN Routern vorgestellt. Abschließend untersuchte eine simulative Leistungsbewertung den Einfluss von WLAN Offloading auf die QoE und den Energieverbrauch von mobilem adaptivem Videostreaming

    Video Conference as a tool for Higher Education

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    The book describes the activities of the consortium member institutions in the framework of the TEMPUS IV Joint Project ViCES - Video Conferencing Educational Services (144650-TEMPUS-2008-IT-JPGR). In order to provide the basis for the development of a distance learning environment based on video conferencing systems and develop a blended learning courses methodology, the TEMPUS Project VICES (2009-2012) was launched in 2009. This publication collects the conclusion of the project and it reports the main outcomes together with the approach followed by the different partners towards the achievement of the project's goal. The book includes several contributions focussed on specific topics related to videoconferencing services, namely how to enable such services in educational contexts so that, the installation and deployment of videoconferencing systems could be conceived an integral part of virtual open campuses

    Mobile Learning Application with Cloud Computing

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    This project focuses on the development of M-Learning and Performance Tracking System at university level. The system provides mobility for the University students to do revision through the exercises and perform immediate tracking and analysis on the results. The project also served as a channel for students to access the latest information and news in the industry. The core problems that I had identified before I initiate this project are the immobility and limited features of current learning system which might causing the ineffective of learning among the university student. The inconvenience of the current system also included the trouble in checking their academic performance constantly from time to time. The primary goal of this research is to investigate the acceptability of the university students of m-learning, designing m-learning features that would help students to improve their academic performance, and develop the system which is able to cater the needs and meet the expectation of the students and lecturers. The methodology adapted in this project is phased development methodology that breaks the projects into 3 stages which are development of quizzes, development of performance tracking and last stage is the library function. The process involved planning, analysis, design, and last but not least implementation. As the result at the end of the project, the result found that the project is feasible with high acceptance level from the university students who believe that mobile learning is useful in learning. However more improvement has to be made on the project especially on the performance tracking method. For future development suggestions, we can adopt several methods in knowledge management in performance tracking to provide more accurate suggestions for the students. Cross platform can be achieved by adapting the HTML5 technology into the development. Cloud computing is important for the development of smartphone program with limited memory and capacity ability

    Coordinated adaptation for adaptive context-aware applications

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    The ability to adapt to change is critical to both mobile and context-aware applications. This thesis argues that providing sufficient support for adaptive context-aware applications requires support for coordinated adaptation. Specifically, the main argument of this thesis is that coordinated adaptation requires applications to delegate adaptation control to an entity that can receive state information from multiple applications and trigger adaptation in multiple applications. Furthermore, coordination requires support for reconfiguration of the adaptive behaviour and user involvement. Failure to support coordinated adaptation is shown to lead to poor system and application performance and insufficient support for user requirements. An investigation of the existing state-of-the-art in the areas of adaptive and context- aware systems and an analysis of the limitations of existing systems leads to the establishment of a set of design requirements for the support of coordinated adaptation. Specifically, adaptation control should be decoupled from the mechanisms implementing the adaptive behaviour of the applications, applications should externalise both state information and the adaptive mechanisms they support and the adaptation control mechanism should allow modifications without the need for re-implementation of either the application or the support platform. This thesis presents the design of a platform derived from the aforementioned re- quirements. This platform utilises a policy based mechanism for controlling adaptation. Based on the particular requirements of adaptive context-aware applications a new pol- icy language is defined derived from Kowalsky’s Event Calculus logic programming formalism. This policy language allows the specification of policy rules where condi- tions are defined through the expression of temporal relationships between events and entities that represent duration (i.e. fluents). A prototype implementation of this design allowed the evaluation of the features offered by this platform. This evaluation reveals that the platform can support coordinated adaptation with acceptable performance cost.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Managing and Securing Business Networks in the Smartphone Era

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    This paper discusses the impact of user owned mobile computing devices (smartphones, tablets, and future devices like Google Glass) on management and security of the corporate network. Personally owned portable computing devices are widely used at work and create a porous network perimeter for the enterprise network. The paper reviews corporate policies posted on websites along with research papers and corporate whitepapers to develop a comprehensive user owned mobile computing device policy. This is a rapidly evolving topic that has not been researched in the business academic literature. We survey trade journals and corporate websites for information regarding this policy and make recommendations that can be applied by business managers

    Library Collection Development Policy

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    Framework para aplicações colaborativas multi-plataforma

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    Dissertação de Mestrado em Engenharia InformáticaCom a massificação de dispositivos móveis “inteligentes”, também conhecidos por smartphones, e o crescente aumento do número destes ligados à internet, surge o desafio de desenvolver aplicações colaborativas viradas para este tipo de dispositivos. Contudo, para isso, é necessário ter um conhecimento das suas limitações de modo a poderem ser feitas as melhores escolhas. Neste sentido, nesta dissertação estudou-se a viabilidade da implementação de funcionalidades colaborativas como videoconferência, whiteboard, remote desktop, desktop sharing e visualização de diapositivos, em dispositivos móveis. De modo a alcançar este objectivo foi necessário estudar quais as tecnologias de desenvolvimento existentes, os diversos protocolos e os requisitos necessários para fazer face aos desafios levantados. Foi, também um objectivo bastante importante que aquando da tomada de decisão da escolha da tecnologia a usar esta tenha a maior transversalidade e ubiquidade possível. Tem que existir um ponto de convergência entre este último requisito e os outros necessários ao desenvolvimento de aplicações que suportem as supra citadas funcionalidades colaborativas. Neste trabalho procedeu-se ao desenvolvimento de um conjunto de widgets que permitem o fácil desenvolvimento de aplicações com este tipo de funcionalidades

    On Providing Energy-efficient Data Transmission to Mobile Devices

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    The transformation from telephony to mobile Internet has fundamentally changed the way we interact with the world by delivering ubiquitous Internet access and reasonable cost of connectivity. The mobile networks and Internet services are supportive of each other and together drive a fast development of new services and the whole ecosystem. As a result, the number of mobile subscribers has skyrocketed to a magnitude of billions, and the volume of mobile traffic has boomed up to a scale no-one has seen before with exponential growth predictions. However, the opportunities and problems are both rising. Therefore, to enable sustainable growth of the mobile Internet and continued mobile service adaption, this thesis proposes solutions to ensure that the reduction of overall environmental presence and the level of QoE are mutually addressed by providing energy-efficient data transmission to mobile devices. It is important to understand the characteristics of power consumption of mobile data transmission to find opportunities to balance the energy consumption and the growth of mobile services and the data volumes. This research started with power consumption measurements of various radio interfaces and investigations of the trade-off between computation and communication of modern mobile devices. Power consumption models, state machines and the conditions for energy-efficient mobile data transmission were proposed to guide the development of energy-saving solutions. This research has then employed the defined guideline to optimise data transmission for energy-efficient mobile web access. Proxy-based solutions are presented in this thesis, utilising several strategies: bundling-enabled traffic shaping to optimise TCP behaviour over congested wireless links and keep the radio interface in low power consumption states as much as possible, offloading HTTP-object fetching to shorten the time of DNS lookups and web content downloading, and applying selective compression on HTTP payload to further reduce energy consumption of mobile data transmission. As a result, the solutions dramatically reduce the energy consumption of mobile web access and download time, yet maintain or even increase user experience
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