Composer System Research Based On Genetic Algorithm

Genetic algorithms, as a computational model simulating the biologicalevolution process of the genetic selection theory of Darwin, is a whole new globaloptimization algorithm and is widely used in many fields with its remarkablecharacteristic of simplicity, commonability, stability, suitability for parallelprocessing, high-efficiency, and practibility . Genetic Algorithms, based on thebiological mechanism of natural selection & heredity and leveraging colonysearching technology, is particularly applicable for the resolution of complicated& non-linear problems intractable with traditional searching methods. And becauseof its independence, global optimization, and implicit parallelism in complexproblem solving, GA is developed and applied in many fields by more and more people.The superiorities of GAs enlighted people to use it in music composing.GAscomposing is the process of controlling the creating of music with GAs. In theprocess of composing, firstly, we should encode the given music, then, we can evolvethe music with crossover operator and mutation operator until we find the satisfyingresults which are scaled with fitness function.Interactive Genetic Algorithm is proposed, in which human evaluation is usedinstead of objective fitness functions in the process of Genetic Algorithm . TheInteractive GA is often applied to the fields in which an appropriate objectivefitness function is difficult to define, for example, the artistic field that makesmuch of human subjective evaluation toward music or painting.When interactive Genetic Algorithm is used in composing, the produced musicfuther adapts to the appreciation custom of the people,at the same time, it canalso overcome the blindness and the randomicity which are caused by common methodsof GA.Thus many people apply this means to composing. This text discusses the rationales and ways of GA composing and analyses thecharacteristics of various kind of GA composing systems and then devises a newinteractive GA composing system.The evolving music in the light of this composingsystem can accord with the actual need. The research contents of this thesis areas follows:1) The thesis analyses the rationales of GA composing and introduce its steps.2) The thesis introduces knowledge about music which is to be used in GAcomposing.3) The thesis makes research on the knowledge representation of GA composing.4) The thesis makes research on the fitness functions of GA composing.5) This text discusses the characteristics and the excellences and the flawsof all kinds of GA composing systems.The major contributions of this thesis are:1) The thesis devises a new kind of representation method about music knowledgewhen GA is used in composing.2) The thesis devises a improved interactive composing system, after theevolution which is defined by the author is finished,the produced music with thiskind of composing system can accord people's enjoying habits.Finally, I point out work which should be done for perfecting GA composingsystems and define the direction of the research in the future for myself.This text improves the current interactive GA composing in some aspects, thenew composing system can enlighten the research about the present GA composingsystem.