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Coleção Digital

Título: EVOLVABLE AUTOMATIC REPAIR AND ADJUSTMENT OF ELECTRONIC CIRCUITS
Instituição: PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO - PUC-RIO
Autor(es):
MARCO AURELIO CAVALCANTI PACHECO - Orientador
Número do Conteúdo: 1819
Catalogação:  13/08/2001 Idioma(s):  PORTUGUESE - BRAZIL

Tipo:  TEXT Subtipo:
Natureza:  SCHOLARLY PUBLICATION
This dissertation investigates the application of Evolvable Hardware Techniques in the process of repair and adjustment of electronic circuits. The objective of this work was to evaluate the performance of evolvable techniques in the repair of defective electronic circuits and in the adjustment of non-optimum circuits, providing theoretical and experimental basis for self-adjustment and self-repair tools. The need of emergency repair tools for electronic circuits, besides the diversity of damages that can be found in various types of circuits has motivated this research. This research had 6 steps: a study on evolvable algorithms and its application in Evolvable Hardware field; a review of multi-objective strategies that motivated the proposal of the parameter Objectives Importance and of a new formula to calculate the error in the Energy Minimization Method; the design of a prototype of reconfigurable platform; the proposal of techniques to extrinsically evolve the repair and to adjust circuits; a proposal of techniques to intrinsically repair and adjust circuits; and the case studies. According to the objective of this work of evaluating the performance of evolvable algorithms in the repair and adjustment of electronic circuits, at first a study on representation, evaluation and operators of these algorithms was done. Multi-objective strategies and its applications in extrinsic and intrinsic evolution for optimisation and synthesis of circuits was also part of this study. As result of this preliminary study, was observed that each objective has a different importance. If this importance is not assigned to the objectives, some circuits may have a good fitness but important objectives may not be satisfied while not so important ones may be. The use of a new parameter called Objectives Importance was proposed to solve this problem. The calculus of the error in the Energy Minimization Method was also reformulated to give more importance to the best individual. The techniques of extrinsic evolvable repair and adjustment proposed here are very similar to the evolvable techniques used to synthesize circuits. The circuits evaluation and algorithms objectives were studied and some changes were proposed. To intrinsically repair circuits is necessary to use a reconfigurable platform of analog circuits. This method is different from the extrinsic one. The individuals representation in this case may vary and depends on the platform used. Techniques to initialise populations were used to seed the population. To make intrinsic evolution experiments possible, a reconfigurable platform for analog circuits called PAMA was designed and implemented. Through the case studies the performance of the techniques proposed were evaluated. Tests with intrinsic and extrinsic systems were done. The relevance and performance of the Objective`s Importance parameter was also studied. Well known analog circuits like TTL gates and amplifiers were used in the experiments. The results showed the accomplishment of such class of techniques and tools, which are very useful to repair circuits, especially in emergencies. Due to the viability of using evolvable techniques and its advantages when compared to the regular methods, the plans are, in future work, to keep testing variations of these methods and testing these techniques in bigger circuits.