962 resultados para Digital to Analog Converter
Resumo:
The challenge of reducing carbon emission and achieving emission target until 2050, has become a key development strategy of energy distribution for each country. The automotive industries, as the important portion of implementing energy requirements, are making some related researches to meet energy requirements and customer requirements. For modern energy requirements, it should be clean, green and renewable. For customer requirements, it should be economic, reliable and long life time. Regarding increasing requirements on the market and enlarged customer quantity, EVs and PHEV are more and more important for automotive manufactures. Normally for EVs and PHEV there are two important key parts, which are battery package and power electronics composing of critical components. A rechargeable battery is a quite important element for achieving cost competitiveness, which is mainly used to story energy and provide continue energy to drive an electric motor. In order to recharge battery and drive the electric motor, power electronics group is an essential bridge to convert different energy types for both of them. In modern power electronics there are many different topologies such as non-isolated and isolated power converters which can be used to implement for charging battery. One of most used converter topology is multiphase interleaved power converter, pri- marily due to its prominent advantages, which is frequently employed to obtain optimal dynamic response, high effciency and compact converter size. Concerning its usage, many detailed investigations regarding topology, control strategy and devices have been done. In this thesis, the core research is to investigate some branched contents in term of issues analysis and optimization approaches of building magnetic component. This work starts with an introduction of reasons of developing EVs and PEHV and an overview of different possible topologies regarding specific application requirements. Because of less components, high reliability, high effciency and also no special safety requirement, non-isolated multiphase interleaved converter is selected as the basic research topology of founded W-charge project for investigating its advantages and potential branches on using optimized magnetic components. Following, all those proposed aspects and approaches are investigated and analyzed in details in order to verify constrains and advantages through using integrated coupled inductors. Furthermore, digital controller concept and a novel tapped-inductor topology is proposed for multiphase power converter and electric vehicle application.
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This paper proposes to promote autonomy in digital ecosystems so that it provides agents with information to improve the behavior of the digital ecosystem in terms of stability. This work proposes that, in digital ecosystems, autonomous agents can provide fundamental services and information. The final goal is to run the ecosystem, generate novel conditions and let agents exploit them. A set of evaluation measures must be defined as well. We want to provide an outline of some global indicators, such as heterogeneity and diversity, and establish relationships between agent behavior and these global indicators to fully understand interactions between agents, and to understand the dependence and autonomy relations that emerge between the interacting agents. Individual variations, interaction dependencies, and environmental factors are determinants of autonomy that would be considered. The paper concludes with a discussion of situations when autonomy is a milestone
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This is a talk on the new University Open Data Service, some of the applications it's already being put to, and some of the things we hope to do next.
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This document details the legal agreement that conference participants will need to sign so that the University can video, stream and store recordinsg of the sessions.
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El estudio analiza los determinantes de uso y acceso a las tecnologías de información y comunicación en personas de bajos ingresos en pasases como Colombia, México y Perú. El punto central está en analizar las diferencias entre países de acuerdo a diferentes variables socioeconómicas. Se encuentra que la variable que más explica el nivel de acceso digital es la escolaridad. De otro lado no se encuentra una brecha por género sino en Perú. Los resultados también indican que cuando solo se tienen en cuenta las tecnologías más ‘avanzadas’, las diferencias entre la población son más notorias
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Desde el campo de la informática educativa, varios autores exponen el posible efecto positivo de incorporar videojuegos y simulaciones con elementos de juego en los procesos educativos. Esta postura continúa siendo objeto de debate y sus detractores identifican, dos problemas fundamentales, por un lado el excesivo coste de estas iniciativas y, por otro, su carácter limitado que obliga a que formen parte de variados procesos educativos.. En este trabajo se estudia cómo abordar estos dos problemas desde un punto de vista tecnológico. Se propone una plataforma menor que e-adventure, un entorno de desarrollo para juegos educativos. Esta plataforma aborda el primer problema planteando, un modelo de proceso de desarrollo inspirado en la aproximación documental al desarrollo de software. El modelo de proceso incluye la propuesta de un lenguaje de marcado extendido, XML, específico del dominio de las aventuras gráficas educativas. Este lenguaje es sencillo de utilizar y facilita la creación de este tipo de juegos e incluye construcciones específicamente educativas que dan soporte a la evaluación de la actividad del alumno y a patrones de aprendizaje adaptativo. El segundo problema se aborda proponiendo la integración de dichos juegos con plataformas de tele-enseñanza, LMS, que se emplean tanto en la enseñanza a través de internet como en aproximaciones del aprendizaje electrónico, e-learning, combinadas con la enseñanza tradicional.. Se incluye la implementación de un prototipo de la plataforma propuesta y varios juegos educativos desarrollados con ella, en colaboración con investigadores e instructores de otros campos..
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El test de circuits és una fase del procés de producció que cada vegada pren més importància quan es desenvolupa un nou producte. Les tècniques de test i diagnosi per a circuits digitals han estat desenvolupades i automatitzades amb èxit, mentre que aquest no és encara el cas dels circuits analògics. D'entre tots els mètodes proposats per diagnosticar circuits analògics els més utilitzats són els diccionaris de falles. En aquesta tesi se'n descriuen alguns, tot analitzant-ne els seus avantatges i inconvenients. Durant aquests últims anys, les tècniques d'Intel·ligència Artificial han esdevingut un dels camps de recerca més importants per a la diagnosi de falles. Aquesta tesi desenvolupa dues d'aquestes tècniques per tal de cobrir algunes de les mancances que presenten els diccionaris de falles. La primera proposta es basa en construir un sistema fuzzy com a eina per identificar. Els resultats obtinguts son força bons, ja que s'aconsegueix localitzar la falla en un elevat tant percent dels casos. Per altra banda, el percentatge d'encerts no és prou bo quan a més a més s'intenta esbrinar la desviació. Com que els diccionaris de falles es poden veure com una aproximació simplificada al Raonament Basat en Casos (CBR), la segona proposta fa una extensió dels diccionaris de falles cap a un sistema CBR. El propòsit no és donar una solució general del problema sinó contribuir amb una nova metodologia. Aquesta consisteix en millorar la diagnosis dels diccionaris de falles mitjançant l'addició i l'adaptació dels nous casos per tal d'esdevenir un sistema de Raonament Basat en Casos. Es descriu l'estructura de la base de casos així com les tasques d'extracció, de reutilització, de revisió i de retenció, fent èmfasi al procés d'aprenentatge. En el transcurs del text s'utilitzen diversos circuits per mostrar exemples dels mètodes de test descrits, però en particular el filtre biquadràtic és l'utilitzat per provar les metodologies plantejades, ja que és un dels benchmarks proposats en el context dels circuits analògics. Les falles considerades son paramètriques, permanents, independents i simples, encara que la metodologia pot ser fàcilment extrapolable per a la diagnosi de falles múltiples i catastròfiques. El mètode es centra en el test dels components passius, encara que també es podria extendre per a falles en els actius.
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To understand what are the most significant factors for digital TV adoption by the Portuguese population in the switchover context is the main goal of the research project here presented. In April 26, 2012, the analogue terrestrial television switchoff is planned to occur in Portugal, according to the schedule published by the national telecommunication regulator Anacom. Digital terrestrial TV was launched in the country in April 2009, making Portugal one of the countries with a more ambitious schedule – or risky, depending on the perspective - for the full transition from analogue to digital terrestrial television. In this paper we will start by presenting the research project’s objectives, theoretical framework and research design. Next, we will present first results of the project focused on the barriers and drivers to digital TV adoption from two of the empirical studies which integrate it, namely, the quantitative inquiry administered to a representative sample of the Portuguese population and interviews with main stakeholders in the area of digital TV in Portugal. The perspectives of the television viewers are compared with other main stakeholders in this process. The paper will be concluded with a brief discussion of these results and a brief enumeration of next steps for the project.
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The success of the transition from analogical terrestrial television to digital terrestrial television – process also known as switch-over – requires the identification of barriers and drivers among the impacted population. Therefore, the study in which this article is based had as main purpose to understand exactly what are those barriers, in order to produce a valid contribution to the several decision makers, and to be able to contribute to a more inclusive television, accessible and transversal to the whole of the population. In that sense, one of the phases of the project consisted in several interviews to key stakeholders in the transition process, the results of which and subsequent recommendations are presented in this article.
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We have designed and implemented a low-cost digital system using closed-circuit television cameras coupled to a digital acquisition system for the recording of in vivo behavioral data in rodents and for allowing observation and recording of more than 10 animals simultaneously at a reduced cost, as compared with commercially available solutions. This system has been validated using two experimental rodent models: one involving chemically induced seizures and one assessing appetite and feeding. We present observational results showing comparable or improved levels of accuracy and observer consistency between this new system and traditional methods in these experimental models, discuss advantages of the presented system over conventional analog systems and commercially available digital systems, and propose possible extensions to the system and applications to nonrodent studies.
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An improved amplifier for atmospheric fine wire resistance thermometry is described. The amplifier uses a low excitation current (50 mu A). This is shown to ensure negligible self-heating of the low mass fine wire resistance sensor, compared with measured nocturnal surface air temperature fluctuations. The system provides sufficient amplification for a +/- 50 degrees C span using a +/- 5 V dynamic range analog-to-digital converter, with a noise level of less than 0.01 degrees C. A Kelvin four-wire connection cancels the effect of long lead resistances: a 50 m length of screened cable connecting the Reading design of fine wire thermometer to the amplifier produced no measurable temperature change at 12 bit resolution.