Abstract. Evolutionary algorithms need measures of how appropriate a solution is in order to make decisions. This is always a problem for evolving art as codifying aesthetics is a complex task. In this paper we consider the problem of evaluating melodies. The evaluation of melodies in evolutionary music is an open problem that has been tackled by many authors with interactive evaluation, fitness-free genetic algorithms and even neural networks. However, all approaches based on formal analysis of databases or formal music theory have been partial, which is something to be expected for such a complex problem. Thus, we present many metrics that can be used for evaluating melodies and their practical results when applied to a Bossa Nova database of melodies coded by the authors. Although the paper is meant to extend the cycle of possible ideas for evolutionary composers, we argue that there is still much to be developed in this field and each genre of music will always need specific measures of quality.

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O texto discute o processo de composição de quatro obras do autor utilizando as noções de “material musical” e “modelo”. Modelo seria uma combinação de traços formais que se extrai de um material musical com o objetivo de se projetar em outro contexto. Os modelos envolvem princípios de organização que se aplicam a diferentes aspectos da dimensão formal da música. São analisados diversos trechos de peças do autor a partir das mesmas noções. Discute-se também a utilização da modelagem computacional (CAC) no processode composição.