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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Métodos eficientes na estimativa de produtividade para o dimensionamento automático de circuitos integrados analógicos

Domanski, Robson André 13 December 2016 (has links)
Submitted by Marlucy Farias Medeiros (marlucy.farias@unipampa.edu.br) on 2017-10-02T18:12:15Z No. of bitstreams: 1 Robson André Domanski - 2016.pdf: 5137261 bytes, checksum: 1e4aac0a601a8fb57b3a32e21268568a (MD5) / Approved for entry into archive by Marlucy Farias Medeiros (marlucy.farias@unipampa.edu.br) on 2017-10-04T17:34:54Z (GMT) No. of bitstreams: 1 Robson André Domanski - 2016.pdf: 5137261 bytes, checksum: 1e4aac0a601a8fb57b3a32e21268568a (MD5) / Made available in DSpace on 2017-10-04T17:34:54Z (GMT). No. of bitstreams: 1 Robson André Domanski - 2016.pdf: 5137261 bytes, checksum: 1e4aac0a601a8fb57b3a32e21268568a (MD5) Previous issue date: 2016-12-13 / O projeto de circuitos integrados analógicos, dentro da indústria da microeletrônica tem a sua evolução ditada pela grande necessidade da integração de circuitos mistos. Esta evolução faz com que os dispositivos semicondutores sejam cada vez mais miniaturizados, o que implica na complexidade cada vez maior no processo de fabricação, resultando em uma grande variabilidade de parâmetros. Esta complexidade no projeto está diretamente ligada ao dimensionamento dos dispositivos que compõem o circuito, já que o espaço de projeto é altamente não-linear. O dimensionamento de circuito analógico pode ser modelado como um problema de otimização e resolvido por heurísticas de otimização. A solução resultante é dependente da estratégia de modelagem e na estimativa de desempenho, o que é feito, em geral, por simulação elétrica. Neste contexto, foi desenvolvida a ferramenta UCAF. No entanto, a solução otimizada cai na fronteira do espaço de projeto, onde uma pequena variação nos parâmetros do dispositivo afeta o desempenho do circuito. Isso conduz à inclusão de simulação Monte Carlo no circuito de otimização, aumentando o esforço computacional. O objetivo principal deste trabalho é analisar dois métodos diferentes de amostragem, a fim de reduzir o número de rodadas Monte Carlo, e a inserção da heurística de otimização Particle Swarm Optimization, visando a minimização do tempo necessário para o dimensionamento do circuito. A amostragem por hipercubo latino, a qual requer um número menor de amostras para um nível de confiança razoável, é utilizado nas primeiras iterações do processo de otimização. Depois de um certo ponto, o método de amostragem é alterado para a amostragem aleatória tradicional. A heurística Particle Swarm Optimization foi implementada na ferramenta UCAF, devido ao seu baixo custo computacional. A metodologia é aplicada para o dimensionamento de um amplificador de transcondutância operacional OTA Miller e um amplificador Telescopic, mostrando vantagens em termos de tempo de processamento e desempenho do circuito. Pode-se demonstrar que a utilização de uma nova heurística, e diferentes métodos de amostragem para a simulação Monte Carlo no processo de otimização produz uma busca mais eficiente no espaço de projeto com um ganho em relação ao esforço computacional. / The analog integrated circuit design within the microelectronics industry has its evolution dictated by the great need for integration of mixed circuits. This trend makes the semiconductor devices are increasingly miniaturized, which implies the increasing complexity in the manufacturing process, resulting in a large variability op parameters. This complexity is directly linked to the design of devices that compose the circuit, since the design space is highly nonlinear. The design of analog circuit can be modeled as an optimization problem and solved by optimization heuristics. The resulting solution is dependent on modeling strategy and performance estimation, which is done generally by electrical simulation. In this context, the UCAF tool was developed. However, the optimized solution falls on the border of the design space where a small variation in device parameters affect circuit performance. This leads to the inclusion of Monte Carlo simulation on the circuit optimization, increasing the computational effort. The main objective of this study is to analyze two different methods of sampling, in order to reduce the number of Monte Carlo runs, and the inclusion of a new heuristic optimization, in order to minimize the time required for the design of the circuit. The Latin hypercube sampling, which requires a smaller number of samples for a reasonable confidence level is used in the first iteration of the optimization process. After a certain point, the sampling method is changed to the traditional random sampling. Heuristic Particle Swarm Optimization was implemented in UCAF tool, due to its low computational cost. The methodology is applied for the design of a Miller and a Telescopic operational transconductance amplifier, showing advantages in terms of processing time and circuit performance. We can demonstrate that the use of a new heuristic, and different methods of sampling for Monte Carlo simulation in the optimization process produces a more efficient search of the design space, and advantages in relation to computational effort.
2

Developing UCAF, an administrative functionality for the U-Call IVR reporting system

Rostami, Asreen January 2014 (has links)
Mobile phones and Interactive Voice Response (IVR) applications are being progressively used in developing countries to collect voice-based reports about bad governance or poor public service delivery, reported by citizens. Such systems (e.g. Avaaj Otalo, Foroba Blon, etc.) can give an opportunity to rural users in developing countries to easily influence and participate in public affairs. Despite the ongoing efforts on using such solutions, the lack of an efficient system of administration can cause delays in broadcasting the collected reports as quickly as possible, to reach the relevant authorities. This thesis presents the results of a real-world deployment of an administrative functionality for an IVR system called U-Call, used in the Northern districts of Uganda. U-Call Administrative Functionality (UCAF) interacts with the U-Call administrators through mobile phones and gives the moderator access to the registered users. It allows administrators to easily publish and tag audio reports over the Web using their mobile phones. It also uses a semantic tagging module to increase findability and information categorization on the U-Call’s website. After an initial validation and successful evaluation of UCAF in the field, during a trip to Uganda, additional features were incorporated, such as multiple authentication process and dynamic tagging. UCAF and its additional features was succefully delivered to the end user, as part of the  U-Call reporting system. / People’s Voices: Developing Cross Media Services to Promote Citizens Participation in Local Governance Activities

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