Sistema de emulação de aerogeradores para aplicação em geração distribuída de energia elétrica

Power generation from alternative sources is at present the subject of numerous research and development in science and industry. Wind energy stands out in this scenario as one of the most prominent alternative in the generation of electricity, by its numerous advantages. In research works, computer reproduction and experimental behavior of a wind turbine are very suitable tools for the development and study of new technologies and the use of wind potential of a given region. These tools generally are desired to include simulation of mechanical and electrical parameters that directly affect the energy conversion. This work presents the energy conversion process in wind systems for power generation, in order to develop a tool for wind turbine emulation testing experimental, using LabVIEW® software. The purpose of this tool is to emulate the torque developed in an axis wind turbine. The physical setup consists of a three phase induction motor and a permanent magnet synchronous generator, which are evaluated under different wind speed conditions. This tool has the objective to be flexible to other laboratory arrangements, and can be used in other wind power generation structures in real time. A modeling of the wind power system is presented, from the turbine to the electrical generator. A simulation tool is developed using Matlab/Simulink® with the purpose to pre-validate the experiment setup. Finally, the design is implemented in a laboratory setup.

Diagnóstico automático de eventos e distúrbios em unidades geradoras e usinas utilizando lógica fuzzy

The electric power systems are getting more complex and covering larger areas day by day. This fact has been contribuiting to the development of monitoring techniques that aim to help the analysis, control and planning of power systems. Supervisory Control and Data Acquisition (SCADA) systems, Wide Area Measurement Systems and disturbance record systems. Unlike SCADA and WAMS, disturbance record systems are mainly used for offilne analysis in occurrences where a fault resulted in tripping of and apparatus such as a transimission line, transformer, generator and so on. The device responsible for record the disturbances is called Digital Fault Recorder (DFR) and records, basically, electrical quantities as voltage and currents and also, records digital information from protection system devices. Generally, in power plants, all the DFRs data are centralized in the utility data centre and it results in an excess of data that difficults the task of analysis by the specialist engineers. This dissertation shows a new methodology for automated analysis of disturbances in power plants. A fuzzy reasoning system is proposed to deal with the data from the DFRs. The objective of the system is to help the engineer resposnible for the analysis of the DFRs’s information by means of a pre-classification of data. For that, the fuzzy system is responsible for generating unit operational state diagnosis and fault classification.

Analysis of the "Sonar Hopf" Cochlea

The "Sonar Hopf" cochlea is a recently much advertised engineering design of an auditory sensor. We analyze this approach based on a recent description by its inventors Hamilton, Tapson, Rapson, Jin, and van Schaik, in which they exhibit the "Sonar Hopf" model, its analysis and the corresponding hardware in detail. We identify problems in the theoretical formulation of the model and critically examine the claimed coherence between the described model, the measurements from the implemented hardware, and biological data.

An explanation of consumer trust recovery in a food retailer

An organization trusted by consumers enjoys a number of benefits. Unfortunately, instances of trust-damaging events involving organizations happen often. Damaged consumer trust in an organization has numerous negative consequences for the organization and for consumers. Currently, there is a paucity of theory about consumer trust recovery. So, understanding why and how consumer trust recovery occurs is timely, and theoretically and practically relevant. However, the findings from this study suggest that we need to distinguish between two kinds of consumer trust recovery. The first (I call it unconscious consumer trust recovery) refers to trust recovery that occurs without the consumer being fully conscious of it. In other words, a consumer is aware of their damaged trust during the scandal, but is not aware that their trust in the organization has improved. The consumer does not think about his or her recovered trust, just as they did not think about their level of trust before the scandal. The consumer trust is habitual. The second (I call it conscious consumer trust recovery) refers to an improvement in damaged trust where the consumer is fully conscious of their trust recovery. In other words, in conscious trust recovery the consumer is aware that the scandal damaged their trust in the organization. Also, after the scandal, in contrast to unconscious trust recovery, in conscious trust recovery the consumer is also fully aware that he trusts the organization as much or more than during the scandal. My aim is to inductively develop a theory explaining each type of consumer trust recovery. To do so, I use Charmazian grounded theory methodology, because this methodology is developed for theory-building from data and is aligned with the philosophical underpinnings of this study. The empirical context for this study is the meat adulteration scandal (“the horse meat scandal”) in 2013 in the UK. I collect and analyse empirical data about both types of trust recovery in an organization from 31 consumers that experienced both types. My analysis shows that when consumers perceive the scandal as less important, they experience unconscious trust recovery. This happens because the reduced importance of the scandal leads to a shift in consumers’ attention, which in turn leads to their inattentiveness to the scandal. Consumer inattentiveness is an immediate antecedent of unconscious trust recovery. Conscious consumer trust recovery occurs because consumers see cues indicating to them that the food retailer has improved product control systems, which in turn leads to consumer perceptions of the organization’s renewed ability. Consumer perception of renewed ability is an immediate antecedent of their conscious trust recovery. My findings lead me to make three main theoretical contributions to the theory of trust recovery in general and to consumer trust recovery in particular. The first contribution lies in showing that there are two types of consumer trust recovery in an organization, not one, as previously conceptualised, and that the same consumers can experience both types. The second contribution is a theory of unconscious consumer trust recovery in an organization that involves three concepts: consumers’ perceived importance of the scandal, consumers’ shift of attention, and consumer inattentiveness. The third contribution is the finding that conscious recovery of consumer trust occurs even when existing theory of trust recovery would predict that it would not. This study can help managers aiming to repair consumer trust in an organization by identifying a set of antecedents and underlying mechanisms that can guide such trust repair.

Strategiaprosessi monikansallisessa yrityksessä

Tämän kandidaatintutkielman tavoitteena on tunnistaa strategiaprosessin eri vaiheet sekä kuvailla, miten prosessi toteutettiin tapausyritys Suominen Oyj:llä. Tavoitteina on myös analysoida, miten Suominen Oyj:n henkilöstö kokee oman suhteensa organisaatioon, sen strategiaan, tavoitteisiin ja arvoihin. Analyysin pohjalta pyritään muodostamaan kuva siitä, kuinka strategian implementoinnissa on onnistuttu. Lisäksi tarkastellaan, eroavatko nämä kokemukset eri maissa tapausyrityksessä. Tutkimuksessa käytetään sekä kvalitatiivisia että kvantitatiivisia tutkimusmenetelmiä. Suominen Oyj:n strategiaprosessista hankitaan informaatiota kahdella laadullisella puolistrukturoidulla teemahaastattelulla. Kvantitatiivisen analyysin kohteena puolestaan on tapausyrityksen yhdeksältäkymmeneltä ylimmässä asemassa työskentelevältä henkilöltä kerätty tilastollinen kyselydata, jota analysoidaan muun muassa Kruskal-Wallisin testillä sekä Spearmanin korrelaatioanalyysillä. Tutkielmassa muodostetaan kuva prosessista, jossa hyvin muotoiltu strategia sekä selkeät tavoitteet luovat pohjan strategian implementoinnille. Onnistuneen implementoinnin keinoja ovat muun muassa kehitysohjelmat, tarkka rekrytointi, tavoitteiden ja palkkioiden sitominen strategiaan, strategian kanssa yhteensopiva organisaatiokulttuuri, useamman eri hierarkiatason osallistuminen ja erilaisten kontrollijärjestelmien sekä implementointityökalujen hyödyntäminen. Havaitaan, että tapausyritys käyttää näistä keinoista useampaa. Yrityksen monikansallisuus vaikuttaa erityisesti organisaatiokulttuuriin sekä sisäiseen viestintään. Tutkielman kvantitatiivisen analyysin tulokset näyttävät, ettei maiden välillä ole tilastollisesti merkittäviä eroja siinä, miten henkilöstö kokee oman suhteensa tapausyritykseen, sen strategiaan, tavoitteisiin ja arvoihin. Kvantitatiivisen analyysin perusteella Suominen Oyj:n strategiaprosessi on onnistunut hyvin. Tutkimuksessa esitellään vielä muutamia kehitysajatuksia yritystä sekä mahdollisia jatkotutkimuksia varten.

Lógica borrosa para la estimación de estados críticos de una pila de combustible PEM

La determinación en tiempo real de los estados críticos de operación de la pila de combustible de membrana intercambio protónico (siglas en ingles, PEM) es uno de los principales retos para los sistemas de control de pilas de combustible PEM. En este trabajo, se presenta el desarrollo e implementación de un método no invasivo de bajo coste basado en técnicas de decisión borrosa que permite estimar los estados críticos de operación de la pila de combustible PEM. La estimación se realiza mediante perturbaciones al estado de operación de la pila y el análisis posterior de la evolución temporal del voltaje generado por la pila. La implementación de esta técnica de estimulación-percepción de estado de la pila de combustible para la detección de estados críticos constituye una novedad y un paso hacia el control autónomo en óptimas condiciones de la operación de las pilas de combustible PEM.

Sistema supervisor inteligente para procesos de producción de petróleo

Maximizar la producción de pozos de crudo pesado y extra pesado es el principal beneficio que se desea obtener de los sistemas de control que están corrientemente operativos en empresas de petróleo. Dada la naturaleza compleja y cambiante con el tiempo de los métodos existentes de levantamiento artificial para extracción de crudo, se dificulta el cumplimiento de las especificaciones pre establecidas para el procesamiento del crudo por parte de los lazos de control regulatorios. Tomando esto en cuenta, en éste trabajo se propone un sistema de supervisión inteligente que permite detectar cambios en las condiciones de operación del proceso productivo y realizar ajustes automáticos de sus consignas. Además, el sistema supervisor propuesto tiene la capacidad de detectar fallas en los sensores involucrados en los lazos de control, garantizando de esta manera una operación confiable del proceso. La propuesta fue probada en un pozo de petróleo real obteniéndose resultados que superaron las expectativas iniciales.

A future dynamically reconfigurable automotive software system

Embedded software systems in vehicles are of rapidly increasing commercial importance for the automotive industry. Current systems employ a static run-time environment; due to the difficulty and cost involved in the development of dynamic systems in a high-integrity embedded control context. A dynamic system, referring to the system configuration, would greatly increase the flexibility of the offered functionality and enable customised software configuration for individual vehicles, adding customer value through plug-and-play capability, and increased quality due to its inherent ability to adjust to changes in hardware and software. We envisage an automotive system containing a variety of components, from a multitude of organizations, not necessarily known at development time. The system dynamically adapts its configuration to suit the run-time system constraints. This paper presents our vision for future automotive control systems that will be regarded in an EU research project, referred to as DySCAS (Dynamically Self-Configuring Automotive Systems). We propose a self-configuring vehicular control system architecture, with capabilities that include automatic discovery and inclusion of new devices, self-optimisation to best-use the processing, storage and communication resources available, self-diagnostics and ultimately self-healing. Such an architecture has benefits extending to reduced development and maintenance costs, improved passenger safety and comfort, and flexible owner customisation. Specifically, this paper addresses the following issues: The state of the art of embedded software systems in vehicles, emphasising the current limitations arising from fixed run-time configurations; and the benefits and challenges of dynamic configuration, giving rise to opportunities for self-healing, self-optimisation, and the automatic inclusion of users’ Consumer Electronic (CE) devices. Our proposal for a dynamically reconfigurable automotive software system platform is outlined and a typical use-case is presented as an example to exemplify the benefits of the envisioned dynamic capabilities.

Otimização de controle de tráfego em grupo de elevadores com algoritmos bioinspirados

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2015.

Airport ground movement

Worldwide air traffic tends to increase and for many airports it is no longer an op-tion to expand terminals and runways, so airports are trying to maximize their op-erational efficiency. Many airports already operate near their maximal capacity. Peak hours imply operational bottlenecks and cause chained delays across flights impacting passengers, airlines and airports. Therefore there is a need for the opti-mization of the ground movements at the airports. The ground movement prob-lem consists of routing the departing planes from the gate to the runway for take-off, and the arriving planes from the runway to the gate, and to schedule their movements. The main goal is to minimize the time spent by the planes during their ground movements while respecting all the rules established by the Ad-vanced Surface Movement, Guidance and Control Systems of the International Civil Aviation. Each aircraft event (arrival or departing authorization) generates a new environment and therefore a new instance of the Ground Movement Prob-lem. The optimization approach proposed is based on an Iterated Local Search and provides a fast heuristic solution for each real-time event generated instance granting all safety regulations. Preliminary computational results are reported for real data comparing the heuristic solutions with the solutions obtained using a mixed-integer programming approach.

Modelagem de um sistema de planejamento em radioterapia e medicina nuclear com o uso do código MCNP6

Tese (Doutorado em Tecnologia Nuclear)

Estabelecimento de um sistema padrão primário para raios X baixas com uma câmara de ionização de ar livre de energias

Dissertação (Mestrado em Tecnologia Nuclear)

Modeling perspective for the relevant market of voice services: mobile to mobile

Los mercados asociados a los servicios de voz móvil a móvil, brindados por operadoras del Sistema Móvil Avanzado en Latinoamérica, han estado sujetos a procesos regulatorios motivados por la dominancia en el mercado de un operador, buscando obtener óptimas condiciones de competencia. Específicamente en Ecuador, la Superintendencia de Telecomunicaciones (Organismo Técnico de Control de Telecomunicaciones) desarrolló un modelo para identificar acciones de regulación que puedan proporcionar al mercado efectos sostenibles de competencia en el largo plazo. Este artículo trata sobre la aplicación de la ingeniería de control para desarrollar un modelo integral del mercado, empleando redes neuronales para la predicción de trarifas de cada operador y un modelo de lógica difusa para predecir la demanda. Adicionalmente, se presenta un modelo de inferencia de lógica difusa para reproducir las estrategias de mercadeo de los operadores y la influencia sobre las tarifas. Dichos modelos permitirían la toma adecuada de decisiones y fueron validados con datos reales.

A educação do século XXI nas mãos da inteligência coletiva : narradores midiáticos nos reflexos dos narcisos digitais

Com a proliferação das mídias, conectadas à rede mundial de computadores, tem-se expandido as oportunidades de expressão e criação de um público cada vez mais crescente. Este advento tecnológico, associado às características do sujeito pertencente ao conceito denominado modernidade líquida, vêm alterando gradualmente as relações sociais. A motivação deste trabalho advém da urgência em sinalizar ao contexto educativo, desde o ensino básico ao acadêmico, sobre as alterações ocorridas no perfil de seu público alvo, tornando-se necessária uma revisão nos métodos, para que esses venham acrescentar abordagens aos desafios emergentes. O primeiro objetivo, a partir do referencial teórico e estudo de caso, visa identificar as características do sujeito influenciado pelo consumismo midiático, apontando para as narrativas transmídia como influências advindas do mercado de consumo interativo, destacando, contudo o interesse pela arte da narrativa. O segundo objetivo, na mesma estrutura, procura destacar exemplos de metodologias que têm o contexto acadêmico como lócus de integração e diálogos entre áreas afins. Também, procura aproximar do contexto dos meios de comunicação transmidiáticas, em seus regimes de controle, recursos de consumo e processos formativos informais, advindos destas dinâmicas. O terceiro objetivo propõe reflexões sobre os resultados de uma proposta com dois grupos de pesquisa e os expectadores de uma instalação de arte digital intitulada E-Reflexos. A dinâmica permeou em integrar os estudantes e espectadores em mestiçagens, unindo abordagens metodológicas aos conhecimentos prévios, na criação de narrativas e jogos, onde os conceitos e reflexões, advindos deste trabalho, foram problematizados e avaliados. O quarto objetivo integra reflexões sobre os principais resultados dos objetivos acima, considerando que é possível ao contexto acadêmico mediar propostas que venham reverter o potencial narrador midiático emergente para o contexto cultural, destacando a relevância das áreas de Arte nesse processo formativo.

Carrier Selection for Multi-commodity Flow Optimization in Cooperative Environments

Part 18: Optimization in Collaborative Networks