732 research outputs found

    A combined algorithm approach for PD location estimation using RF antennas

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    To locate the positions of partial discharge sources in free space at least four RF antennas are arranged in a suitable spatial geometry to detect the radiated electromagnet energy from the discharge. The time-difference-of-arrival (TDOA) between the signals from each antenna are then used within multi-lateration equations to determine the position of the source. The iterative Hyperbolic Least Squares (HLS) method and the non-iterative Maximum Likelihood Estimator (MLE) method are two common techniques used in the literature to solve the multi-lateration equations. This paper investigates the ability of combining MLE and HLS to improve location accuracy and maintain fast location computation time. To this end HLS, MLE and the combined MLEHLS method are evaluated in terms of location accuracy and computation performance for three spatial antenna configurations, namely Square, Pyramidal and Trapezoidal arrangements. The location accuracies for each method are evaluated for theoretical TDOA values and also for the case when a finite sampling rate of 10G samples-per-second is considered, the latter is implemented through appropriate rounding up of TDOA values by one sample time. It is shown that MLE-HLS produces improved location accuracy compared with HLS and MLE for both theoretical and finite sampled TDOA values. In addition, it is shown that MLE-HLS improves significantly the computation time over the iterative HLS method

    A combined algorithm approach for PD location estimation using RF antennas

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    To locate the positions of partial discharge sources in free space at least four RF antennas are arranged in a suitable spatial geometry to detect the radiated electromagnet energy from the discharge. The time-difference-of-arrival (TDOA) between the signals from each antenna are then used within multi-lateration equations to determine the position of the source. The iterative Hyperbolic Least Squares (HLS) method and the non-iterative Maximum Likelihood Estimator (MLE) method are two common techniques used in the literature to solve the multi-lateration equations. This paper investigates the ability of combining MLE and HLS to improve location accuracy and maintain fast location computation time. To this end HLS, MLE and the combined MLEHLS method are evaluated in terms of location accuracy and computation performance for three spatial antenna configurations, namely Square, Pyramidal and Trapezoidal arrangements. The location accuracies for each method are evaluated for theoretical TDOA values and also for the case when a finite sampling rate of 10G samples-per-second is considered, the latter is implemented through appropriate rounding up of TDOA values by one sample time. It is shown that MLE-HLS produces improved location accuracy compared with HLS and MLE for both theoretical and finite sampled TDOA values. In addition, it is shown that MLE-HLS improves significantly the computation time over the iterative HLS method

    Dynamic Evaluation of Production Policies: Improving the Coordination of an Ethanol Supply Chain

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    AbstractThis paper uses System Dynamics modeling and process simulation to explore coordination in two logistic processes (procurement and production) of the supply chain of an ethanol plant. In that sense, three production scenarios are evaluated to identify: a) stock movement according to current inventory policies, and b) the critical variables affecting the coordination for these two processes. Since the main goal in the company is to meet customer demand, this research incorporates sales forecasting, and four performance indicators to evaluate the state of the processes: 1) average percentage of demand satisfaction, 2) maximum amount of ethanol in excess, 3) available ethanol at the end of the year, and 4) inventory costs. To model the case study, the change in production yield and specific constraints for the chain are considered. The simulation results show that System Dynamics modeling can be used to observe the effects of policies on inventory, and meeting the demand in a real system. It also can define the coordination for a supply chain and give information to improve it. The developed model uses STELLA® software to simulate the logistic processes and execute the evaluation employing the performance indicators

    Real-time optimization of the key filtration parameters in an AnMBR: Urban wastewater mono-digestion vs. co-digestion with domestic food waste

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    [EN] This study describes a model-based method for real-time optimization of the key filtration parameters in a submerged anaerobic membrane bioreactor (AnMBR) treating urban wastewater (UWW) and UWW mixed with domestic food waste (FW). The method consists of an initial screening to find out adequate filtration conditions and a real-time optimizer applied to a periodically calibrated filtration model for minimizing the operating costs. The initial screening consists of two statistical analyses: (1) Morris screening method to identify the key filtration parameters; (2) Monte Carlo method to establish suitable initial control inputs values. The operating filtration cost after implementing the control methodology was (sic)0.047 per m(3) (59.6% corresponding to energy costs) when treating UWW and 0.067 per m(3) when adding FW due to higher fouling rates. However, FW increased the biogas productivities, reducing the total costs to (sic)0.035 per m(3). Average downtimes for reversible fouling removal of 0.4% and 1.6% were obtained, respectively. The results confirm the capability of the proposed control system for optimizing the AnMBR performance when treating both substrates. (C) 2018 Elsevier Ltd. All rights reserved.This research work was possible thanks to financial support from Generalitat Valenciana (project PROMETEO/2012/029) which is gratefully acknowledged. Besides, support from FCC Aqualia participation in INNPRONTA 2011 IISIS IPT-20111023 project (partially funded by The Centre for Industrial Technological Development (CDTI) and from the Spanish Ministry of Economy and Competitiveness) is gratefully acknowledged.Robles Martínez, Á.; Capson-Tojo, G.; Ruano García, MV.; Seco Torrecillas, A.; Ferrer, J. (2018). Real-time optimization of the key filtration parameters in an AnMBR: Urban wastewater mono-digestion vs. co-digestion with domestic food waste. Waste Management. 80:299-309. https://doi.org/10.1016/j.wasman.2018.09.031S2993098

    The influence of antenna positioning errors on the radio-frequency localization of partial discharges sources

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    Congreso online, sin sede definida. ABSTRACT: Electrical insulation can have imperfections due to manufacturing or ageing. When the insulation is electrically stressed, partial discharge (PD) pulses, with very fast rise-times and short-time durations, may occur. One of the consequences of charges being accelerated within the discharge is the emission of electromagnetic energy. The measurement of these emissions is widely used to identify defective insulation within high voltage equipment and help in predictive and planned maintenance in order to prevent sudden failure. The location of the source of the radiated PD signals may be determined using multi-lateration techniques using an array of at least four antennas. Depending on the relative position between the antennas and the PD source, the pulsed emissions from the PD source arrive at each antenna at different times. The relative time differences of arrivals (TDOA) together with the antenna positions are variables used to locate the PD source in 3D space. This paper investigates the accuracy of the location determination of the source as a consequence of systematic errors on the positioning of the antennas. These errors are analyzed for three different antenna array configurations and for different vector directions from the arrays. Additionally, the least sensitive layout in relation to antenna positioning errors is proposed to assist in improving the location accuracy of PD sources.Simulations were undertaken at the Universidad Carlos III of Madrid and the University of Strathclyde Glasgow. The work undertaken in this paper has been funded by the Spanish Government under contract DPI2015-66478-C2-1. Jose M. Fresno received an international travel grant from the Universidad Carlos III of Madrid

    Survey on the Performance of Source Localization Algorithms

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    The localization of emitters using an array of sensors or antennas is a prevalent issue approached in several applications. There exist different techniques for source localization, which can be classified into multilateration, received signal strength (RSS) and proximity methods. The performance of multilateration techniques relies on measured time variables: the time of flight (ToF) of the emission from the emitter to the sensor, the time differences of arrival (TDoA) of the emission between sensors and the pseudo-time of flight (pToF) of the emission to the sensors. The multilateration algorithms presented and compared in this paper can be classified as iterative and non-iterative methods. Both standard least squares (SLS) and hyperbolic least squares (HLS) are iterative and based on the Newton&-Raphson technique to solve the non-linear equation system. The metaheuristic technique particle swarm optimization (PSO) used for source localisation is also studied. This optimization technique estimates the source position as the optimum of an objective function based on HLS and is also iterative in nature. Three non-iterative algorithms, namely the hyperbolic positioning algorithms (HPA), the maximum likelihood estimator (MLE) and Bancroft algorithm, are also presented. A non-iterative combined algorithm, MLE-HLS, based on MLE and HLS, is further proposed in this paper. The performance of all algorithms is analysed and compared in terms of accuracy in the localization of the position of the emitter and in terms of computational time. The analysis is also undertaken with three different sensor layouts since the positions of the sensors affect the localization; several source positions are also evaluated to make the comparison more robust. The analysis is carried out using theoretical time differences, as well as including errors due to the effect of digital sampling of the time variables.Simulations were undertaken at the Universidad Carlos III of Madrid and at the University of Strathclyde, Glasgow. The work undertaken in this paper has been funded by the Spanish Government under Contract DPI2015-66478-C2-1(MINECO/FEDER, UE) 2016–2018

    Impact of different levels of handling on Solea senegalensis culture: effects on growth and molecular markers of stress

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    [EN] Aquaculture routine practices may cause stress induction on the fish and compromise their welfare affecting the production. This experiment aimed to evaluate the potential links between handling during culture with stress responses and growth on Senegalese sole (Solea senegalensis). We worked with two fish cohorts in terms of initial body weight and culture stage: Trial 1 included specimens in the fattening stage (226 ± 4.96 g) and Trial 2 animals in the pre-fattening stage (27.20 ± 0.44 g). The tested culture protocol, which lasted 6 and 4 months for Trial 1 and 2, respectively, mainly reduced handling-derived stressors in the experimental tanks via lowering routine samplings to a minimum. This decrease of the handling-derived stress was reflected in both trials with lower concentration of circulating cortisol in blood plasma from the experimental fish when compared to controls. Moreover, the proposed protocol promoted higher growth in the fish cultured in the less disturbing protocol in Trial 2. Higher specific growth rates and mean body weight and length were reported. In order to further explore the potential beneficial effects of our protocol, we studied the musculoskeletal from Trial 2 gene expression of key genes regulating glucocorticoid signaling pathway and apoptosis: glucocorticoid receptors 1 and 2 (gr1, gr2), heat shock protein 90 AA (hsp90aa), and caspase 6 (casp6). In line with the cortisol reduced level in this trial, gr1, hsp90aa, and casp6 genes showed lower expression in the samples coming from the experimental group. The findings of this study provide valuable information to the aquaculture industry for the management of Solea senegalensis stress and welfare.SIPublicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL

    Proyecto eMadrid: metodologías educativas, ludificación y calidad

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    Esta comunicación presenta un conjunto de trabajos de investigación sobre metodologías docentes, ludificación y calidad realizados en el seno del proyecto eMadrid, de la Comunidad Autónoma de Madrid. En primer lugar se resumen los trabajos realizados en los dos primeros años del proyecto. Posteriormente se presentan las líneas de trabajo previstas para los dos años restantesEstos trabajos se han financiado parcialmente por el proyecto eMadrid (S2013/ICE-2715) de la Comunidad de Madrid, los proyectos FLEXOR (TIN2014-52129-R), RESET (TIN2014-53199-C3-1-R) e iProg (TIN2015-66731-C2-1-R) del Ministerio de Economía y Competitividad, y el proyecto “Adaptación de la metodología PhyMEL a la formación clínica mediante el uso de simuladores” financiado por la empresa Medical Simulato

    Jogo de rol como teste informatizado para avaliar a resolução de conflitos na infância

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    This paper presents the results from developing an online role-playing game based on simulated situations for assessing the resolutions of conflicts in childhood. We compare the answers provided by two groups of children who answered the computer game test and the board game version with the presence of an interviewer. The results indicate that children who answered the computer-based test were more inclined to attack, than those who answered the board game version. As a conclusion, we can state that the decisions children made in the different situations varied according to a greater or lesser expectation of social sanction when answering the questions. In this way, the use of computer-based tests and simulated situations may help to study spontaneous responses that reflect everyday behaviorSe presentan los resultados del desarrollo de un videojuego online como test informatizado basado en situaciones simuladas para acceder a la resolución de conflictos en la infancia. Comparamos las respuestas dadas por dos grupos de niños quienes respondieron la versión del juego de computador y la versión del juego de mesa con presencia de un entrevistador. Como conclusión se pudo establecer que las decisiones que los niños toman en las distintas situaciones varían de acuerdo a una mayor o menor expectativa de sanción social al responder las preguntas. En este sentido, el uso de test informatizados y la simulación de situaciones podría ayudar a estudiar respuestas más espontáneas que reflejen comportamientos cotidianosEste trabalho apresenta os resultados do desenvolvimento de um videogame online como uma prova computadorizada baseado em situações simuladas para acessar a resolução de conflitos na infância. Comparamos as respostas dadas por dois grupos de crianças que responderam à versão do jogo de computador e à versão do jogo de tabuleiro com a presença de um entrevistador. Como conclusão, foi estabelecido que as decisões que as crianças fazem em diferentes situações variam de acordo com uma maior ou menor expectativa de sanção social ao responder as perguntas. Nesse sentido, o uso de testes computadorizados e a simulação de situações podem ajudar a estudar respostas mais espontâneas que refletem os comportamentos diários das crianças
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