8,082 research outputs found

    Mobility Management for Cellular Networks:From LTE Towards 5G

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    Design and low energy ventilation solutions for atria in the tropics

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    A generic atrium building was designed to incorporate low energy solutions and features of both vernac�ular and contemporary South Asian architecture. To achieve low energy and comfort within the atrium space, some key design variables were examined by running a dynamic thermal model (DTM) for some representative cases. This DTM model was developed with multiple levels and zones to simulate the heat and air movement throughout the building and validated with the data measured in a real building of similar form. The modelling study was carried out to investigate the effects of two roof forms for the atrium and three low cost ventilation solutions on indoor thermal comfort. It reveals that low cost ven�tilation and acceptable comfort are achievable in this traditional form of architecture and low energy solutions and careful design can complement well its functional aspects and even enhance its aesthetic and practical qualities. The solar heat gain, air temperature, and mean radiant temperature in the atrium were used to assess the effectiveness of clerestory windows with opaque rooftop (i.e. side-lit model) as compared to the fully transparent glazed rooftop (i.e. top-lit model). Data on cooling loads, indoor air temperature, and mean radiant temperature were used to evaluate the design options with special consideration on local adaptable thermal comfort criteria. The possible effects of the research outcomes on the incorporation of atria are discussed at the end

    Optimized Camera Handover Scheme in Free Viewpoint Video Streaming

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    Free-viewpoint video (FVV) is a promising approach that allows users to control their viewpoint and generate virtual views from any desired perspective. The individual user viewpoints are synthetized from two or more camera streams and correspondent depth sequences. In case of continuous viewpoint changes, the camera inputs of the view synthesis process must be changed in a seamless way, in order to avoid the starvation of the viewpoint synthesizer algorithm. Starvation occurs when the desired user viewpoint cannot be synthetized with the currently streamed camera views, thus the FVV playout interrupts. In this paper we proposed three camera handover schemes (TCC, MA, SA) based on viewpoint prediction in order to minimize the probability of playout stalls and find the tradeoff between the image quality and the camera handover frequency. Our simulation results show that the introduced camera switching methods can reduce the handover frequency with more than 40%, hence the viewpoint synthesis starvation and the playout interruption can be minimized. By providing seamless viewpoint changes, the quality of experience can be significantly improved, making the new FVV service more attractive in the future

    At the Locus of Performance: A Case Study in Enhancing CPUs with Copious 3D-Stacked Cache

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    Over the last three decades, innovations in the memory subsystem were primarily targeted at overcoming the data movement bottleneck. In this paper, we focus on a specific market trend in memory technology: 3D-stacked memory and caches. We investigate the impact of extending the on-chip memory capabilities in future HPC-focused processors, particularly by 3D-stacked SRAM. First, we propose a method oblivious to the memory subsystem to gauge the upper-bound in performance improvements when data movement costs are eliminated. Then, using the gem5 simulator, we model two variants of LARC, a processor fabricated in 1.5 nm and enriched with high-capacity 3D-stacked cache. With a volume of experiments involving a board set of proxy-applications and benchmarks, we aim to reveal where HPC CPU performance could be circa 2028, and conclude an average boost of 9.77x for cache-sensitive HPC applications, on a per-chip basis. Additionally, we exhaustively document our methodological exploration to motivate HPC centers to drive their own technological agenda through enhanced co-design

    A CFD based procedure for airspace integration of small unmanned aircraft within congested areas

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    Future integration of small unmanned aircraft within an urban airspace requires an a posteriori understanding of the building-induced aerodynamics which could negatively impact on vehicle performance. Moving away from generalised building formations, we model the centre of the city of Glasgow using Star-CCMþ, a commercial CFD package. After establishing a critical turbulent kinetic energy for our vehicle, we analyse the CFD results to determine how best to operate a small unmanned aircraft within this environment. As discovered in a previous study, the spatial distribution of turbulence increases with altitude. It was recommended then that UAVs operate at the minimal allowable altitude within a congested area. As the flow characteristics in an environment are similar, regardless of inlet velocity, we can determine areas within a city which will have consistently low or high values of turbulent kinetic energy. As the distribution of turbulence is dependent on prevailing wind directions, some directions are more favourable than others, even if the wind speed is unchanging. Moving forward we should aim to gather more information about integrated aircraft and how they respond to turbulence in a congested area

    Magnetoencephalography in Stroke Recovery and Rehabilitation

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    Magnetoencephalography (MEG) is a non-invasive neurophysiological technique used to study the cerebral cortex. Currently, MEG is mainly used clinically to localize epileptic foci and eloquent brain areas in order to avoid damage during neurosurgery. MEG might, however, also be of help in monitoring stroke recovery and rehabilitation. This review focuses on experimental use of MEG in neurorehabilitation. MEG has been employed to detect early modifications in neuroplasticity and connectivity, but there is insufficient evidence as to whether these methods are sensitive enough to be used as a clinical diagnostic test. MEG has also been exploited to derive the relationship between brain activity and movement kinematics for a motor-based brain-computer interface. In the current body of experimental research, MEG appears to be a powerful tool in neurorehabilitation, but it is necessary to produce new data to confirm its clinical utility
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