Evolutionary Design of Generic Structures Using Instruction-Based Development

Evolutionary algorithm, instruction, program, continual development,parametric development, environment, combinational logic circuit,
general solution, generic structure.

Computational development rerpesents an extensive subset of theevolutionary design area. In general, the development is intended as anadditional mechanism of evolutionary algorithm attempting to overcomethe problem of scale that represent a crucial issue during theevolutionary design. Many models and techniques have been introduced sofar, including their applications in various fields. This PhD thesisintroduces a new class of developmental methods called aninstruction-based development. The key feature is the evolution ofapplication-specific programs, consisting of simple instructions, whichis similar to the linear genetic programming approach. The concept ofprograms, in fact, enables to establish an universal computationalmodel depending on the instruction set involved, interpretation and wayof execution of the instructions. The program, represented as asequence of instructions, can thus specify an arbitrary algorithm whichis understood as a prescription for the development construction) of atarget object. The objective of this work is to apply theinstruction-based development to design generic structures.Combinational circuits have been chosen as suitable domain todemonstrate the capabilities of this approach. Experiments have beenconducted, Two different approaches to the instruction-baseddevelopment have been introduced. The first approach has been called acontinual development. The target circuit can grow from an initialsolution theoretically infinitely, preserving a desired function allthe time during the development. A case study of the continualdevelopment is presented in the domain of the evolutionary design ofgeneric sorting networks. It has been shown that the evolution is ableto discover innovative solutions which exhibit better parameters incomparison with a conventional principle. The general properties of thebest result have been demonstrated formally. Moreover, evolution ofgeneric polymorphic circuits has been presented using the continualdevelopment approach. The second approach represents a parametricdevelopment. In this case the target circuit is developed every timefrom the start, while the size of its target instance is specified by aparameter. An external information, that we called an environment, hasbeen introduced into the developmental system in order to developgeneric structures containing irregular parts. The experiments havebeen conducted in the area of the evolutionary design of genericcombinational multipliers. Two variants of a parametric developmentalsystem have been presented. The first one represents an initialexperiment of the evolution of common generic multipliers using thedevelopment, whilst the second one is intended to design effectivegeneric carry-save multipliers. In general, ve have introduced anextensive set of experiments demonstrating the capability of theproposed concepts of instruction-based development to design variousgeneric structures, including a discovery of some new generalinnovative solutions.

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