Video over DSL with LDGM Codes for Interactive Applications

Digital Subscriber Line (DSL) network access is subject to error bursts, which, for interactive video, can introduce unacceptable latencies if video packets need to be re-sent. If the video packets are protected against errors with Forward Error Correction (FEC), calculation of the application-layer channel codes themselves may also introduce additional latency. This paper proposes Low-Density Generator Matrix (LDGM) codes rather than other popular codes because they are more suitable for interactive video streaming, not only for their computational simplicity but also for their licensing advantage. The paper demonstrates that a reduction of up to 4 dB in video distortion is achievable with LDGM Application Layer (AL) FEC. In addition, an extension to the LDGM scheme is demonstrated, which works by rearranging the columns of the parity check matrix so as to make it even more resilient to burst errors. Telemedicine and video conferencing are typical target applications

Device Performance of Emerging Photovoltaic Materials (Version 2)

Following the 1st release of the “Emerging photovoltaic (PV) reports”, the best achievements in the performance of emerging photovoltaic devices in diverse emerging photovoltaic research subjects are summarized, as reported in peer-reviewed articles in academic journals since August 2020. Updated graphs, tables, and analyses are provided with several performance parameters, e.g., power conversion efficiency, open-circuit voltage, short-circuit current density, fill factor, light utilization efficiency, and stability test energy yield. These parameters are presented as a function of the photovoltaic bandgap energy and the average visible transmittance for each technology and application and are put into perspective using, e.g., the detailed balance efficiency limit. The 2nd instalment of the “Emerging PV reports” extends the scope toward tandem solar cells and presents the current state-of-the-art in tandem solar cell performance for various material combinations

Bayesian approach and Naturalness in MSSM analyses for the LHC

The start of LHC has motivated an effort to determine the relative probability of the different regions of the MSSM parameter space, taking into account the present, theoretical and experimental, wisdom about the model. Since the present experimental data are not powerful enough to select a small region of the MSSM parameter space, the choice of a judicious prior probability for the parameters becomes most relevant. Previous studies have proposed theoretical priors that incorporate some (conventional) measure of the fine-tuning, to penalize unnatural possibilities. However, we show that such penalization arises from the Bayesian analysis itself (with no ad hoc assumptions), upon the marginalization of the mu-parameter. Furthermore the resulting effective prior contains precisely the Barbieri-Giudice measure, which is very satisfactory. On the other hand we carry on a rigorous treatment of the Yukawa couplings, showing in particular that the usual practice of taking the Yukawas "as required", approximately corresponds to taking logarithmically flat priors in the Yukawa couplings. Finally, we use an efficient set of variables to scan the MSSM parameter space, trading in particular B by tan beta, giving the effective prior in the new parameters. Beside the numerical results, we give accurate analytic expressions for the effective priors in all cases. Whatever experimental information one may use in the future, it is to be weighted by the Bayesian factors worked out here.Comment: LaTeX, 19 pages, 3 figure

Aproximación al control de la microestructura de dos aceros microaleados con contenido medio de carbono en condiciones de conformado en caliente

El objetivo principal de este trabajo es estudiar el comportamiento a fluencia de dos aceros microaleados de contenido medio de carbono, en condiciones de conformado en caliente analizando su evolución microstructural a través de la dependencia del tamaño de grano recristalizado (Drec) con el parámetro de Zener-Hollomon, Z. Se observó que esta dependencia muestra un comportamiento bimodal asociado a la transición entre la recristalización dinámica cíclica y de pico simple. También, se ha observado que la variación del Drec normalizado por el vector de Burgers (b) con la tensión de estado estable sss a su vez normalizada por el modulo de cizalladura (m) exhibe el mismo comportamiento bimodal arriba mencionado. Debido a la complejidad de los dos aceros estudiados, el tamaño de grano recristalizado no se ajusta a la ecuación universal de Derby. Para explicar este comportamiento cabe pensar en el efecto de los precipitados y de la microestructura inicial sobre el tamaño de grano recristalizado. The main aim of the present investigation was to study the flow behaviour of two medium carbon microalloyed steels under hot forming conditions, and to analyse their microstructural evolution. The dependence of recrystallized grain size (Drec) on the Zener-Hollomon parameter Z shows a bimodal behaviour with transition from single to cyclic dynamic recrystallization. We also observed that the variation of Drec normalized by the Burgers vector (b) with the steady state stress sss normalized by shear modulus (m) shows the same bimodal behaviour cited above. The Derby’s universal equation reported in the literature for recrystallized grain sizes was not followed; it seems that the presence of fine precipitated particles has a clear effect on this disagreementPeer ReviewedPostprint (published version

Including leakage in network models: an application to calibrate leak valves in EPANET

EPANET is one of the most widely used software packages for water network hydraulic modelling, and is especially interesting for educational and research purposes because it is in the public domain. However, EPANET simulations are demand-driven, and the program does not include a specific functionality to model water leakage, which is pressure-driven. Consequently, users are required to deal with this drawback by themselves. As a general solution for this problem, this paper presents a methodology for including leakage in EPANET models by following a two-stage process. Firstly, leakage is spatially distributed among the nodes, according to the characteristics of the network. Secondly, leakage is modelled through an emitter at each node. The process is described in detail and two numerical examples illustrate the applicability and advantages of the method. In addition, free access through a URL is provided to the leakage modelling tool that has been developed.Cobacho Jordán, R.; Arregui De La Cruz, F.; Soriano Olivares, J.; Cabrera Rochera, E. (2015). Including leakage in network models: an application to calibrate leak valves in EPANET. Journal of Water Supply: Research and Technology - Aqua. 64(2):130-138. doi:10.2166/aqua.2014.197S130138642Al-Ghamdi, A. S. (2011). Leakage–pressure relationship and leakage detection in intermittent water distribution systems. Journal of Water Supply: Research and Technology-Aqua, 60(3), 178-183. doi:10.2166/aqua.2011.003Almandoz, J., Cabrera, E., Arregui, F., Cabrera, E., & Cobacho, R. (2005). Leakage Assessment through Water Distribution Network Simulation. Journal of Water Resources Planning and Management, 131(6), 458-466. doi:10.1061/(asce)0733-9496(2005)131:6(458)Ameyaw, E. E., Memon, F. A., & Bicik, J. (2013). Improving equity in intermittent water supply systems. Journal of Water Supply: Research and Technology-Aqua, 62(8), 552-562. doi:10.2166/aqua.2013.065Boulos, P. F., & Bros, C. M. (2010). Assessing the carbon footprint of water supply and distribution systems. Journal - American Water Works Association, 102(11), 47-54. doi:10.1002/j.1551-8833.2010.tb11338.xCabrera, E., Pardo, M. A., Cobacho, R., & Cabrera, E. (2010). Energy Audit of Water Networks. Journal of Water Resources Planning and Management, 136(6), 669-677. doi:10.1061/(asce)wr.1943-5452.0000077Cabrera, E., Cobacho, R., Estruch, V., & Aznar, J. (2011). Analytical hierarchical process (AHP) as a decision support tool in water resources management. Journal of Water Supply: Research and Technology-Aqua, 60(6), 343-351. doi:10.2166/aqua.2011.016Cassa, A. M., & van Zyl, J. E. (2013). Predicting the head-leakage slope of cracks in pipes subject to elastic deformations. Journal of Water Supply: Research and Technology-Aqua, 62(4), 214-223. doi:10.2166/aqua.2013.094Cavallo, A., Di Nardo, A., De Maria, G., & Di Natale, M. (2013). Automated fuzzy decision and control system for reservoir management. Journal of Water Supply: Research and Technology-Aqua, 62(4), 189-204. doi:10.2166/aqua.2013.046Colombo, A. F., & Karney, B. W. (2002). Energy and Costs of Leaky Pipes: Toward Comprehensive Picture. Journal of Water Resources Planning and Management, 128(6), 441-450. doi:10.1061/(asce)0733-9496(2002)128:6(441)Prats, A. G., Picó, S. G., Alzamora, F. M., & Bello, M. Á. J. (2012). Random Scenarios Generation with Minimum Energy Consumption Model for Sectoring Optimization in Pressurized Irrigation Networks Using a Simulated Annealing Approach. Journal of Irrigation and Drainage Engineering, 138(7), 613-624. doi:10.1061/(asce)ir.1943-4774.0000452Germanopoulos, G. (1985). A technical note on the inclusion of pressure dependent demand and leakage terms in water supply network models. Civil Engineering Systems, 2(3), 171-179. doi:10.1080/02630258508970401GERMANOPOULOS, G., & JOWITT, P. (1989). LEAKAGE REDUCTION BY EXCESS PRESSURE MINIMIZATION IN A WATER SUPPLY NETWORK. Proceedings of the Institution of Civil Engineers, 87(2), 195-214. doi:10.1680/iicep.1989.2003Giustolisi, O., Savic, D., & Kapelan, Z. (2008). Pressure-Driven Demand and Leakage Simulation for Water Distribution Networks. Journal of Hydraulic Engineering, 134(5), 626-635. doi:10.1061/(asce)0733-9429(2008)134:5(626)Islam, M. S., Sadiq, R., Rodriguez, M. J., Francisque, A., Najjaran, H., Naser, B., & Hoorfar, M. (2012). Evaluating leakage potential in water distribution systems: a fuzzy-based methodology. Journal of Water Supply: Research and Technology - Aqua, 61(4), 240-252. doi:10.2166/aqua.2012.151Kleiner, Y., & Rajani, B. (2002). Forecasting Variations and Trends in Water-Main Breaks. Journal of Infrastructure Systems, 8(4), 122-131. doi:10.1061/(asce)1076-0342(2002)8:4(122)Shamir, U., & Howard, C. D. D. (1979). An Analytic Approach to Scheduling Pipe Replacement. Journal - American Water Works Association, 71(5), 248-258. doi:10.1002/j.1551-8833.1979.tb04345.xWalski, T. M., & Pelliccia, A. (1982). Economic analysis of water main breaks. Journal - American Water Works Association, 74(3), 140-147. doi:10.1002/j.1551-8833.1982.tb04874.

High-resolution spectro-polarimetry of a flaring sunspot penumbra

We present simultaneous photospheric and chromospheric observations of the trailing sunspot in NOAA 10904 during a weak flare eruption (GOES magnitude B7.8), obtained with the Swedish Solar Telescope (SST) in La Palma, Canary Islands. High-resolution \ion{Ca}{ii} $H$ images show a typical two-ribbon structure that has been hitherto only known for larger flares, and the flare appears in a confined region that is discernible by a bright border. The underlying photosphere shows a disturbed penumbral structure with intersecting branches of penumbral filaments. High-resolution Doppler- and vector-magnetograms exhibit oppositely directed Evershed flows and magnetic field vectors in the individual penumbral branches, resulting in several regions of magnetic azimuth discontinuity and several islands where the vertical magnetic field is reversed. The discontinuity regions are co-spatial with the locations of the onset of the flare ribbons. From the results, we conclude that the confined flare region is detached from the global magnetic field structure by a separatrix marked by the bright border visible in \ion{Ca}{ii} $H$. We further conclude that the islands of reversed vertical field appear because of flux emergence and that the strong magnetic shear appearing in the regions of magnetic azimuth discontinuity triggers the flare.Comment: 20 pages + 1 online Figure for A&

Histological Examination in Obtaining a Diagnosis in Patients with Lymphadenopathy in Lima, Peru.

The differential diagnosis for lymphadenopathy is wide and clinical presentations overlap, making obtaining an accurate diagnosis challenging. We sought to characterize the clinical and radiological characteristics, histological findings, and diagnoses for a cohort of patients with lymphadenopathy of unknown etiology. 121 Peruvian adults with lymphadenopathy underwent lymph node biopsy for microbiological and histopathological evaluation. Mean patient age was 41 years (Interquartile Range 26-52), 56% were males, and 39% were HIV positive. Patients reported fever (31%), weight loss (23%), and headache (22%); HIV infection was associated with fever (P < 0.05) and gastrointestinal symptoms (P < 0.05). Abnormalities were reported in 40% of chest X-rays (N = 101). Physicians suspected TB in 92 patients (76%), lymphoma in 19 patients (16%), and other malignancy in seven patients (5.8%). Histological diagnoses (N = 117) included tuberculosis (34%), hyperplasia (27%), lymphoma (13%), and nonlymphoma malignancy (14%). Hyperplasia was more common (P < 0.001) and lymphoma less common (P = 0.005) among HIV-positive than HIV-negative patients. There was a trend toward reduced frequency of caseous necrosis in samples from HIV-positive than HIV-negative TB patients (67 versus 93%, P = 0.055). The spectrum of diagnoses was broad, and clinical and radiological features correlated poorly with diagnosis. On the basis of clinical features, physicians over-diagnosed TB, and under-diagnosed malignancy. Although this may not be inappropriate in resource-limited settings where TB is the most frequent easily treatable cause of lymphadenopathy, diagnostic delays can be detrimental to patients with malignancy. It is important that patients with lymphadenopathy undergo a full diagnostic work-up including sampling for histological evaluation to obtain an accurate diagnosis