IPTV Over ICN

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

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

IP Over ICN Goes Live

Information-centric networking (ICN) has long been advocating for radical changes to the IP-based Internet. However, the upgrade challenges that this entails have hindered ICN 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. We provide an overview of POINT and outline how it improves upon IP in terms of performance and resilience. Our focus is on the successful trial of the POINT prototype in a production network, where real users operated actual IP-based applications

Effect of operating temperature on degradation of solder joints in crystalline silicon photovoltaic modules for improved reliability in hot climates

Accelerated degradation of solder joint interconnections in crystalline silicon photovoltaic (c-Si PV) modules drives the high failure rate of the system operating in elevated temperatures. The phenomenon challenges the thermo-mechanical reliability of the system for hot climatic operations. This study investigates the degradation of solder interconnections in c-Si PV modules for cell temperature rise from 25 °C STC in steps of 1 °C to 120 °C. The degradation is measured using accumulated creep strain energy density (Wacc). Generated Wacc magnitudes are utilised to predict the fatigue life of the module for ambient temperatures ranging from European to hot climates. The ANSYS mechanical package coupled with the IEC 61,215 standard accelerated thermal cycle (ATC) profile is employed in the simulation. The Garofalo creep model is used to model the degradation response of solder while other module component materials are simulated with appropriate material models. Solder degradation is found to increase with every 1 °C cell temperature rise from the STC. Three distinct degradation rates in Pa/°C are observed. Region 1, 25 to 42 °C, is characterised by degradation rate increasing quadratically from 1.53 to 10.03 Pa/°C. The degradation rate in region 2, 43 to 63 °C, is critical with highest constant magnitude of 12.06 Pa/°C. Region 3, 64 to 120 °C, demonstrates lowest degradation rate of logarithmic nature with magnitude 5.47 at the beginning of the region and 2.25 Pa/°C at the end of the region. The module fatigue life, L (in years) is found to decay according to the power function L=721.48T-1.343. The model predicts module life in London and hot climate to be 18.5 and 9 years, respectively. The findings inform on the degradation of c-Si PV module solder interconnections in different operating ambient temperatures and advise on its operational reliability for improved thermo-mechanical design for hot climatic operations

Are the spectroradiometers used by the PV community ready to accurately measure the classification of solar simulators in a broader wavelength range?

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Analysis of twelve-month degradation in three polycrystalline photovoltaic modules

Polycrystalline silicon photovoltaic (PV) modules have the advantage of lower manufacturing cost as compared to their monocrystalline counterparts, but generally exhibit both lower initial module efficiencies and more significant early-stage efficiency degradation than do similar monocrystalline PV modules. For both technologies, noticeable deterioration in power conversion efficiency typically occurs over the first two years of usage. Estimating PV lifetime by examining the performance degradation behavior under given environmental conditions is, therefore, one of continual goals for experimental research and economic analysis. In the present work, accelerated lifecycle testing (ALT) on three polycrystalline PV technologies was performed in a full-scale, industrial-standard environmental chamber equipped with single-sun irradiance capability, providing an illumination uniformity of 98% over a 2 x 1.6m area. In order to investigate environmental aging effects, time-dependent PV performance (I-V characteristic) was evaluated over a recurring, compressed day-night cycle, which simulated local daily solar insolation for the southwestern United States, followed by dark (night) periods. During a total test time of just under 4 months that corresponded to a year equivalent exposure on a fielded module, the temperature and humidity varied in ranges from 3 degrees C to 40 degrees C and 5% to 85% based on annual weather profiles for Tucson, AZ. Removing the temperature de-rating effect that was clearly seen in the data enabled the computation of normalized efficiency degradation with time and environmental exposure. Results confirm the impact of environmental conditions on the module long-term performance. Overall, more than 2% efficiency degradation in the first year of usage was observed for all thee polycrystalline Si solar modules. The average 5-year degradation of each PV technology was estimated based on their determined degradation rates.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]