978 research outputs found

    Interactive media server with media synchronized raid storage system

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    We propose an efficient placement algorithm and per-disk prefetching method to effectively support interactive operations in the media server. Our placement policy is incorporated with an encoder having a special bitcount control scheme that repeatedly tunes quantization parameters to adjust the bitcounts of video frames. This encoder can generate coded frames whose sizes are synchronized with the RAID stripe size, so that when various fast-forward levels are accessed we can reduce the seek and rotational latency and enhance the disk throughput of each disk in the RAID system. In the experimental results, the proposed placement policy and bitrate control scheme can significantly improve the average service time, which can enlarge the capacity of the interactive media server

    Closed P2P system for PVR-based file sharing

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    Workload-Based ConïŹguration of MEMS-Based Storage Devices for Mobile Systems

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    Because of its small form factor, high capacity, and expected low cost, MEMS-based storage is a suitable storage technology for mobile systems. However, flash memory may outperform MEMS-based storage in terms of performance, and energy-efficiency. The problem is that MEMS-based storage devices have a large number (i.e., thousands) of heads, and to deliver peak performance, all heads must be deployed simultaneously to access each single sector. Since these devices are mechanical and thus some housekeeping information is needed for each head, this results in a huge capacity loss and increases the energy consumption of MEMS-based storage with respect to flash. We solve this problem by proposing new techniques to lay out data in MEMS-based storage devices. Data layouts represent optimizations in a design space spanned by three parameters: the number of active heads, sector parallelism, and sector size. We explore this design space and show that by exploiting knowledge of the expected workload, MEMS-based devices can employ all heads, thus delivering peak performance, while decreasing the energy consumption and compromising only a little on the capacity. Our exploration shows that MEMS-based storage is competitive with flash in most cases, and outperforms flash in a few cases

    Support infrastructures for multimedia services with guaranteed continuity and QoS

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    Advances in wireless networking and content delivery systems are enabling new challenging provisioning scenarios where a growing number of users access multimedia services, e.g., audio/video streaming, while moving among different points of attachment to the Internet, possibly with different connectivity technologies, e.g., Wi-Fi, Bluetooth, and cellular 3G. That calls for novel middlewares capable of dynamically personalizing service provisioning to the characteristics of client environments, in particular to discontinuities in wireless resource availability due to handoffs. This dissertation proposes a novel middleware solution, called MUM, that performs effective and context-aware handoff management to transparently avoid service interruptions during both horizontal and vertical handoffs. To achieve the goal, MUM exploits the full visibility of wireless connections available in client localities and their handoff implementations (handoff awareness), of service quality requirements and handoff-related quality degradations (QoS awareness), and of network topology and resources available in current/future localities (location awareness). The design and implementation of the all main MUM components along with extensive on the field trials of the realized middleware architecture confirmed the validity of the proposed full context-aware handoff management approach. In particular, the reported experimental results demonstrate that MUM can effectively maintain service continuity for a wide range of different multimedia services by exploiting handoff prediction mechanisms, adaptive buffering and pre-fetching techniques, and proactive re-addressing/re-binding

    Design and validation of a meter band rate in OpenFlow and OpenDaylight for optimizing QoS

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    Technological developments in the Internet and communications have created a vastly complex and dynamic context with diverse heterogeneous networks and fast growth of mobile devices and multimedia. As the Internet becomes the primary mode of communication for many organisations there is requirement to enhance quality of service (QoS) from heterogeneous systems and networks. Traditional networks such as TETRA have become increasingly incapable of addressing the demand for media rich, bandwidth intensive traffic flows and applications. Mission-critical multimedia over new generation mobile networks face QoS constraints. This research explores a novel solution for quality of service performance for streaming mission-critical video data in OpenFlow SDN networks. A Meter Band Rate Evaluation (MBE) mechanism is advanced that improves the native QoS capability of OpenFlow and OpenDaylight. The MBE is a physical component added to the OpenFlow meter table to evaluate and dynamically adjust traffic rates and allows the traffic volume to be specified relative to other traffic in the network. Its design and development are presented and the mechanism is verified through a simulated experiment in an SDN testbed. The results identified that QoS performance experienced a significant percentage increase when the MBE was active. These findings contribute a novel Meter Band Rate Evaluation mechanism that extends the native capability of OpenFlow and OpenDaylight to enhance the efficiency of QoS provision

    CCTV Technology Handbook

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    This CCTV Technology Handbook provides emergency responders, law enforcement security managers, and other security specialists with a reference to aid in planning, designing, and purchasing a CCTV system. This handbook includes a description of the capabilities and limitations of CCTV components used in security applications

    CHORUS Deliverable 2.1: State of the Art on Multimedia Search Engines

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    Based on the information provided by European projects and national initiatives related to multimedia search as well as domains experts that participated in the CHORUS Think-thanks and workshops, this document reports on the state of the art related to multimedia content search from, a technical, and socio-economic perspective. The technical perspective includes an up to date view on content based indexing and retrieval technologies, multimedia search in the context of mobile devices and peer-to-peer networks, and an overview of current evaluation and benchmark inititiatives to measure the performance of multimedia search engines. From a socio-economic perspective we inventorize the impact and legal consequences of these technical advances and point out future directions of research

    Joining BitTorrent and swift to improve P2P transfers

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    In the last decade, Internet became a new mean to disseminate information, changing the initial paradigms of the network. At the same time, P2P networks became successful to share data between final users. One of the most successful P2P systems is BitTorrent, responsible of more than the 50% of current Internet traffic. Despite this success, BitTorrent lacks some features to become the silver bullet for massive content distribution. With the aim to solve some of this problem, a new protocol called swift was designed. swift is described to be a multiparty transport protocol, with the mission to efficiently disseminate content among a swarm of peers. Novel structures, advanced requesting/acknowledging techniques and bandwidth-efficient congestion control algorithms were used in the design of the protocol. The goal of this project is to build a first prototype of integration of the new transport protocol into an already existing BitTorrent client. The only current implementation of swift, libswift, will be used as the transport layer. A new module for Tribler must be built in order to join the BitTorrent and the libswift operation
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