8 research outputs found

    IPTV Over ICN

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    The efficient provision of IPTV services requires support for IP multicasting and IGMP snooping, limiting such services to single operator networks. Information-Centric Networking (ICN), with its native support for multicast seems ideal for such services, but it requires operators and users to overhaul their networks and applications. The POINT project has proposed a hybrid, IP-over-ICN, architecture, preserving IP devices and applications at the edge, but interconnecting them via an SDN-based ICN core. This allows individual operators to exploit the benefits of ICN, without expecting the rest of the Internet to change. In this paper, we first outline the POINT approach and show how it can handle multicast-based IPTV services in a more efficient and resilient manner than IP. We then describe a successful trial of the POINT prototype in a production network, where real users tested actual IPTV services over both IP and POINT under regular and exceptional conditions. Results from the trial show that the POINT prototype matched or improved upon the services offered via plain IP

    Improving video QoE with IP over ICN

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    Information-centric networking (ICN) has long been advocating for radical changes to the Internet, but the upgrade challenges that this entails have hindered its adoption. To break this loop, the POINT project proposed a hybrid, IP-over-ICN, architecture: IP networks are preserved at the edge, connected to each other over an ICN core. This exploits the key benefits of ICN, enabling individual network operators to improve the performance of their IP-based services, without changing the rest of the Internet. This paper first provides an overview of POINT and outlines how it can improve upon IP in terms of performance and resilience. It then describes a trial of the POINT prototype in a production network, where real users operated actual IPbased applications. As part of the trial, we carried out experiments to evaluate the Quality of Experience (QoE) for video services offered via either HLS or IPTV, using either IP or POINT as a substrate. The results from the trial verify that the IP-over-ICN approach of POINT offers enhanced QoE to the users of these video services, compared to traditional IP, especially under exceptional network conditions

    Extending the Spectrum Characterisation of Solar Simulators from 300 nm to 1200 nm: Challenges on Spectral Measurements in the UV and NIR

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    Innovative photovoltaic technologies with spectral sensitivity exceeding the 400 to 1100 nm limits (as currently defined by the international standard IEC 60904-9) are nowadays available on the market. This poses new challenges in the correct measurement of the spectral content of solar simulators and natural sunlight in those wavelength bands that lie outside these limits. This study proposes an extension of the IEC 60904-9 bandwidth by adding two bands in the UV (300-400 nm) and NIR (1100-1200 nm) regions. This new proposed extension is analysed in terms of spectral match, using spectral measurements of Global Normal Irradiance (GNI) acquired during the 6th European Spectroradiometer Intercomparison by eight independent laboratories. A laboratory is selected to provide reference spectra, and the spectral match of the other ones is calculated, both on a single-measurement level and on a daily average level. The intra-day and inter-day variations are evaluated as well. Results show that all investigated laboratories are capable to assure a spectral match well below the ±25% limit corresponding to class-A simulators. When the more stringent, informal class-A+ corresponding to the ±12.5% limit is considered, four out of seven laboratories are still compliant with it.JRC.C.2-Energy Efficiency and Renewable

    Spectroradiometry in PV: how inter-laboratory comparison may improve measurement accuracy

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    Spectroradiometry is a key metrological discipline for accurate testing of photovoltaic (PV) devices, particularly relevant both for indoor testing on solar simulators and for outdoor testing, where differences between the available thermal energy and the energy usable by PV modules are relevant. In fact, as to indoor testing, the uncertainty in the spectral mismatch between the testing light source and the reference spectral irradiance may give rise to deviations up to 1-3% when measuring the maximum power even on a Class A solar simulator. Experimental uncertainty is expected to increase even further after the publication of the new revision of IEC 60904-9 (“Solar simulator performance requirements”), which is due by 2018. As to outdoor testing, accurate knowledge of solar spectral irradiance is important also for energy rating purposes, in view of the publication of IEC 61853 part 3 (“Energy rating of PV modules”) and part 4 (“Standard reference climatic profiles”). The relevance of accurate measurements of solar spectral irradiance has led the most renowned accredited European solar PV test centres to take part to a series of International Spetroradiometer Intercomparisons that has taken place every year so far since 2011 in various localities in the Mediterranean Basin. The ever-growing number of participating laboratories is both a consequence and a key of success of the whole exercise: ISO 17025 accredited laboratories are willing to receive confirmation of the stability and accuracy of their spectroradiometers and that can be done only when a conspicuous number of testing centres is involved. This paper summarizes the outcomes of the last intercomparisons, trying to highlight whether improvements in measurement reproducibility can be inferred from those partners that have participated since the earliest editions. The work gives new insights into spectroradiometry for both outdoor and indoor testing applications.JRC.C.2-Energy Efficiency and Renewable
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