373 research outputs found

    Field Trials for the Empirical Characterization of the Low Voltage Grid Access Impedance From 35 kHz to 500 kHz

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    The access impedance of low-voltage (LV) power networks is a major factor related to the performance of the narrow-band power line communications (NB-PLCs) and, in a wider sense, to electromagnetic compatibility (EMC) performance. Up to date, there is still a lack of knowledge about the frequency-dependent access impedance for frequencies above 9 kHz and up to 500 kHz, which is the band where the NB-PLC operates. The access impedance affects the transmission of the NB-PLC signal, and it determines the propagation of the non-intentional emissions that may disturb other electrical devices, including malfunctioning or reduced lifetime of equipment. This paper presents the results of field measurements of the LV access impedance up to 500 kHz in different scenarios, with measurement locations close to end users and near transformers. The results provide useful information to analyze the characteristics of the LV access impedance, including variation with frequency, ranges of values for different frequency bands, and analysis of specific phenomena. Moreover, the results reveal a diverse frequency-dependent behavior of the access impedance in different scenarios, depending on the grid topology, the number of end users (that is, number and type of connected loads), and the type of transformation center. Overall, the results of this paper offer a better understanding of the transmission of NB-PLC signals and EMC-related phenomena.The authors would like to thank Iberdrola for the availability and the collaboration of authorized staff for carrying out the field trials

    Memory-efficient belief propagation for high-definition real-time stereo matching systems

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    Tele-presence systems will enable participants to feel like they are physically together. In order to improve this feeling, these systems are starting to include depth estimation capabilities. A typical requirement for these systems includes high definition, good quality results and low latency. Benchmarks demonstrate that stereo-matching algorithms using Belief Propagation (BP) produce the best results. The execution time of the BP algorithm in a CPU cannot satisfy real-time requirements with high-definition images. GPU-based implementations of BP algorithms are only able to work in real-time with small-medium size images because the traffic with memory limits their applicability. The inherent parallelism of the BP algorithm makes FPGA-based solutions a good choice. However, even though the memory traffic of a commercial FPGA-based ASIC-prototyping board is high, it is still not enough to comply with realtime, high definition and good immersive feeling requirements. The work presented estimates depth maps in less than 40 milliseconds for high-definition images at 30fps with 80 disparity levels. The proposed double BP topology and the new data-cost estimation improve the overall classical BP performance while they reduce the memory traffic by about 21%. Moreover, the adaptive message compression method and message distribution in memory reduce the number of memory accesses by more than 70% with an almost negligible loss of performance. The total memory traffic reduction is about 90%, demonstrating sufficient quality to be classified within the first 40 positions in the Middlebury ranking.This work has been partially supported by the CDTI under project CENIT-VISION 2007-1007 and the CICYT under TEC2008-04107

    Cri-du-chat syndrome mimics Silver-Russell syndrome depending on the size of the deletion: a case report

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    BackgroundSilver-Russell Syndrome (SRS) is a rare growth-related genetic disorder mainly characterized by prenatal and postnatal growth failure. Although molecular causes are not clear in all cases, the most common mechanisms involved in SRS are loss of methylation on chromosome 11p15 (approximate to 50%) and maternal uniparental disomy for chromosome 7 (upd(7)mat) (approximate to 10%).Case presentationWe present a girl with clinical suspicion of SRS (intrauterine and postnatal growth retardation, prominent forehead, triangular face, mild psychomotor delay, transient neonatal hypoglycemia, mild hypotonia and single umbilical artery). Methylation and copy number variations at chromosomes 11 and 7 were studied by methylation-specific multiplex ligation-dependent probe amplification and as no alterations were found, molecular karyotyping was performed. A deletion at 5p15.33p15.2 was identified (arr[GRCh37] 5p15.33p15.2(25942-11644643)x1), similar to those found in patients with Cri-du-chat Syndrome (CdCS). CdCS is a genetic disease resulting from a deletion of variable size occurring on the short arm of chromosome 5 (5p-), whose main feature is a high-pitched mewing cry in infancy, accompanied by multiple congenital anomalies, intellectual disability, microcephaly and facial dysmorphism.ConclusionsThe absence of some CdCS features in the current patient could be due to the fact that in her case the critical regions responsible do not lie within the identified deletion. In fact, a literature review revealed a high degree of concordance between the clinical manifestations of the two syndromes.The costs of the publication and molecular analyses of this research were funded by grants from Instituto de Salud Carlos III (Institute of Health Carlos III) of the Spanish Ministry of Economy and Competitiveness, co-financed by the European Regional Development Fund (PI16/00073), the Department of Health of the Basque Government (GV2016111105; GV2017111040), and the University of the Basque Country UPV/EHU (PIF17/29)

    Estado del arte del proyecto

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    A partir de la capacidad de estructuración que podemos asociar al binomio espacio público – transporte público, la presente investigación pretende profundizar en los aspectos de urbanidad que esta relación puede brindan a la ciudad o a parte de ellas, en razón a, los diferentes grados de religancia e Imbricación urbana (lasos) que se generan entre éstos (la vía y el transporte público (preferentemente guiado)), y las demás instancias urbanas asociadas a un itinerario y, que en última instancia tienen directa relación con la cohesión urbana de un territorio
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