Reliability analysis of distribution systems with photovoltaic generation using a power flow simulator and a parallel Monte Carlo approach

This paper presents a Monte Carlo approach for reliability assessment of distribution systems with distributed generation using parallel computing. The calculations are carried out with a royalty-free power flow simulator, OpenDSS (Open Distribution System Simulator). The procedure has been implemented in an environment in which OpenDSS is driven from MATLAB. The test system is an overhead distribution system represented by means of a three-phase model that includes protective devices. The paper details the implemented procedure, which can be applied to systems with or without distributed generation, includes an illustrative case study and summarizes the results derived from the analysis of the test system during one year. The goal is to evaluate the test system performance considering different scenarios with different level of system automation and reconfiguration, and assess the impact that distributed photovoltaic generation can have on that performance. Several reliability indices, including those related to the impact of distributed generation, are obtained for every scenario.Postprint (published version

A Solid State Transformer model for power flow calculations

This paper presents the implementation of a Solid State Transformer (SST) model in OpenDSS. The goal is to develop a SST model that could be useful for assessing the impact that the replacement of the conventional iron-and-copper transformer with the SST can have on the distribution system performance. Test distribution systems of different characteristics and size have been simulated during different time periods. The simulations have been carried out assuming voltage-dependent loads and considering that power flow through either the HV/MV substation transformer or any of the MV/LV distribution transformers can be bidirectional. Simulation results prove that a positive impact should be expected on voltages at both MV and LV levels, but the efficiency of current SST designs should be improved.Postprint (author's final draft

An Intelligent Traction Control for Motorcycles

The appearance of anti-lock braking systems (ABS) and traction control systems (TCS) have been some of the most major developments in vehicle safety. These systems have been evolving since their origin, always keeping the same objective, by using increasingly sophisticated algorithms and complex brake and torque control architectures. The aim of this work is to develop and implement a new control model of a traction control system to be installed on a motorcycle, regulating the slip in traction and improving dynamic performance of two-wheeled vehicles. This paper presents a novel traction control algorithm based on the use of Artificial Neural Networks (ANN) and Fuzzy Logic. An ANN is used to estimate the optimal slip of the surface the vehicle is moving on. A fuzzy logic control block, which makes use of the optimal slip provided by the ANN, is developed to control the throttle position. Two control blocks have been tuned. The first control block has been tuned according to the experience of an expert operator. The second one has been optimized using Evolutionary Computation (EC). Simulation shows that the use of EC can improve the fuzzy logic based control algorithm, obtaining better results than those produced with the control tuned only by experience.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Efectos agudos y a corto plazo de un protocolo de entrenamiento de arrastres con cargas del 20 y 60% del peso corporal sobre el rendimiento físico y la fatiga muscular

En este trabajo se analizó y comparó el efecto agudo y a corto plazo de un mismo protocolo de entrenamiento de sprint resistido con diferentes cargas sobre el rendimiento físico y la fatiga muscular. Un total de 15 sujetos realizaron 8 sprints resistidos de 20 m con dos situaciones de carga (20% y 60% PC). Las respuestas metabólicas (concentración de lactato en sangre) se midieron antes, a la mitad y al final del entrenamiento de sprint resistido y las variables mecánicas (Altura del salto vertical, Tiempo de sprint en 20 m y Mediciones de fuerza en la flexión y extensión de rodilla en una maquina isoinercial) se cuantificaron tanto antes como al final del entrenamiento y a las 24 horas de haberlo realizado. Se produjo una pérdida de rendimiento significativa dentro del entrenamiento y la concentración del lactato aumento conforme aumentaban el número de repeticiones. La pérdida de rendimiento y la concentración de lactato fue significativamente mayor con la carga del 60% PC que con la carga del 20% PC, por tanto, cuanto mayor es la carga del sprint resistido mayor es la fatiga neuromuscular y metabólica generada. Por otro lado, el salto vertical (CMJ) resultó ser una prueba más sensible que la medición del tiempo de sprint para detectar deterioros agudos en el rendimiento, a pesar de la especificidad de la prueba de sprint. Además, 24 horas parecen ser suficientes para una recuperación completa en el rendimiento de salto vertical.Universidad de Sevilla.Grado en Ciencias de la Actividad Física y del Deport

A review of tools, models and techniques for long-term assessment of distribution systems using OpenDSS and parallel computing

Many distribution system studies require long-term evaluations (e.g. for one year or more): Energy loss minimization, reliability assessment, or optimal rating of distributed energy resources should be based on long-term simulations of the distribution system. This paper summarizes the work carried out by the authors to perform long-term studies of large distribution systems using an OpenDSS-MATLAB environment and parallel computing. The paper details the tools, models, and procedures used by the authors in optimal allocation of distributed resources, reliability assessment of distribution systems with and without distributed generation, optimal rating of energy storage systems, or impact analysis of the solid state transformer. Since in most cases, the developed procedures were implemented for application in a multicore installation, a summary of capabilities required for parallel computing applications is also included. The approaches chosen for carrying out those studies used the traditional Monte Carlo method, clustering techniques or genetic algorithms. Custom-made models for application with OpenDSS were required in some studies: A summary of the characteristics of those models and their implementation are also included.Peer ReviewedPostprint (published version

Assessing attention deficit by binocular rivalry

Objective: To determine whether the frequency and duration of the periods of suppression of a percept in a binocular rivalry (BR) task can be used to distinguish between subjects with attention deficit hyperactivity disorder (ADHD) and controls. Method: 122 participants (6 to 15 years) were assigned to three groups: ADHD Combined (ADHD-C), ADHD-Predominantly Inattentive (ADHD-I) and controls. They each performed a BR task and two measures were recorded: alternation rate and duration of exclusive dominance periods. Results: ADHD-C group presented fewer alternations and showed greater variability than did the control group; results for the ADHD-I group being intermediate between the two. The duration of dominance periods showed a differential profile: in control group it remained stable over time, whereas in the clinical groups it decreased logarithmically as the task progressed. Conclusions: The differences between groups in relation to the BR indicators can be attributed to the activity of involuntary inhibition

Psychometric properties of a test for ADHD based on binocular rivalry

The psychometric properties of a Binocular Rivalry (BR)-based test on a group of 159 participants (57 with attention deficit hyperactivity disorder, ADHD) aged between 6 and 15 years are presented. Two factors, which explained 56.82% of the variance, were obtained by exploratory factor analysis: (a) Alternations and Duration of exclusive dominances, and (b) Decision time. Reliability was excellent (Cronbach's á = .834 and .884). The ADHD group showed fewer alternations and longer duration of dominances and decision time than the control group. Correlations between measures of BR, IQ, working memory, and processing speed of the WISC-IV, and ADHD symptoms, assessed by parents and teachers, ranged between low and medium

El aprendizaje del concepto de fracción, desde la perspectiva histórico-cultural : un camino

RESUMEN: Esta investigación analiza el proceso de aprendizaje del concepto de fracción en seis estudiantes de cuarto grado de una institución educativa ubicada en el municipio de Caucasia-Antioquia, desde la perspectiva histórico-cultural. Esta perspectiva da la posibilidad de comprender, desde autores como Caraça (1984), Lima & Moisés (1998) entre otros, la fracción como un movimiento conceptual que relaciona no sólo aspectos de la medición, sino además, lo que hay detrás de ésta: el movimiento de la magnitud en relación con la esencia del número natural y de la geometría básica, como resultado de pensamiento y lenguaje en la actividad histórico-cultural de la humanidad. Además, la perspectiva histórico-cultural y en particular la teoría de la actividad de Leontiev (1983) retomada para la educación matemática por Davidov (1988) y GEPAPe (2010), ofrece unos fundamentos teóricos que permitieron, por un lado, llevar al aula de clase el conocimiento referido a la fracción (a partir de Actividades Orientadoras de Enseñanza de GEPAPe, 2010) apuntando a una educación humanizadora y; por otro lado, percibir e interpretar la forma en que los estudiantes, protagonistas de la investigación, se aproximaron progresivamente al desarrollo histórico-cultural del movimiento conceptual de la fracción. El procedimiento metodológico utilizado en esta investigación fue la metodología cualitativa con enfoque critico-dialectico y un abordaje de investigación participante. Los datos que se analizaron son producto de las elaboraciones colectivas, individuales y de las discusiones en el aula de clase, al desarrollar las Actividades Orientadoras de Enseñanza. Los resultados obtenidos en este trabajo, permiten disponerlo como un camino que ayuda a formar mejores ciudadanos y, entender cómo las diversas aproximaciones, reflexiones y apropiaciones hechas por los estudiantes, en permanente interacción con otros, les posibilitó aprender la fracción. Teniendo en cuenta, la realidad que les pertenece y de la que hacen parte

Composing textual modelling languages in practice

This is the author's version of the work. It is posted here for your personal use. Not for redistribution. The definitive Version of Record was published in Proceedings of the 6th International Workshop on Multi-Paradigm Modeling, http://dx.doi.org/10.1145/2508443.2508449Complex systems require descriptions using multiple modelling languages, or languages able to express different concerns, like timing or data dependencies. In this paper, we propose techniques for the modular definition and composition of languages, including their abstract, concrete syntax and semantics. These techniques are based on (meta-)model templates, where interface elements and requirements for their connection can be established. We illustrate the ideas using the MetaDepth textual meta-modelling tool