Musical pattern extraction using genetic algorithms

This paper describes a research work in which we study the possibility of applying genetic algorithms to the extraction of musical patterns in monophonic musical pieces. Each individual in the population represents a possible segmentation of the piece being analysed. The goal is to find a segmentation that allows the identification of the most significant patterns of the piece. In order to calculate an individual’s fitness, all its segments are compared among each other. The bigger the area occupied by similar segments the better the quality of the segmentation

Paradigmatic analysis using genetic programming

Paradigmatic analysis consists in the segmentation of a musical piece through the identification of relations between different parts of the piece, and the classification of the identified segments into categories. In this paper we describe how a genetic programming system can be used to make the paradigmatic analysis of monophonic musical pieces, using a simple fitness function inspired in the Kolmogorov complexity estimation. We make use of automatically defined functions in order to represent segments. Relations are made explicit through the reuse of segments and the application of transformations to these segments

Composing music with case-based reasoning

Comunicação apresentada na International Conference on Computational Models of Creative Cognition, Dublin, 1997.Music is one of the most intriguing and joyful domain of research and analysis. Driven by this insatiable curiosity, Musical Analysis has emerged to formally understand and structure music and its intrinsic intention and causality. Each complete analysis of a piece points to issues that go far beyond the normal graphical music representation. A better analysis is important not only to a better interpretation, but also to a more perfect composition. An exceptional composer is indeed an exceptional analyst. This paper presents a computational approach to music composition through the use and exploration of musical analysis. Centered on Case-Based Reasoning and Planning techniques, it consists on creating new solutions by keeping, transforming and extrapolating knowledge from already expert-made music analysis. For our approach, each analysis is represented as a precisely structured Case, divisible into all of its components. The process of composition we adopt is progressive, left-to-right, and top-to-bottom and has some similarities with (Wallas’ 1926) theory for creative production (Macedo et al. 1996a) which we adapted for this specifically structured and complex domain. The resulting implemented program has already generated several different musical pieces, which were examined and analyzed by experts, bringing up precious questions and advice

Towards a computational case-based model for creative planning

This paper describes a computational case-based model for the creative planning process. Our approach is inspired in Wallas’ model for the creative process in that we consider that creativity involves a sequence of four stages: preparation, incubation, illumination and verification. Preparation includes problem acquisition and assimilation of background knowledge, which is represented by cases, i.e., documented past experiences. With the aim of achieving a flexible knowledge representation, as a means to potentiate specific creative abilities like Fluency, Synthesis and Analysis, we structure each case as a network of hierarchically and temporally related case pieces. These case pieces can be considered individually, providing better recombinations of them. These recombinations, rather than made by chance, are guided by those hierarchical and temporal case piece relations (or explanations). We explain the role of opportunistic knowledge acquisition at the incubation stage. We sustain that illumination may comprise recursive calls of the sequence of the first three stages. This computational model is implemented in the system INSPIRER (ImagiNation1 taking as Source Past and Imperfectly RElated Reasonings). An application in musical composition domain is presented. We also show how a musical composition task may be cognitively modelled and treated as a planning task. We also present a short example illustrating how INSPIRER generates music

A structured framework for representing time in a generative composition system

The representation of music structures is, from Musicology to Artificial Intelligence, a widely known research focus. It entails several generic Knowledge Representation problems like structured knowledge representation, time representation and causality. In this paper, we focus the problem of representing and reasoning about time in the framework of a structured music representation approach, intended to support the development of a Case-Based generative composition system. The basic idea of this system is to use Music Analysis as foundation for a generative process of composition, providing a structured and constrained way of composing novel pieces, although keeping the essential traits of the composer’s style. We propose a solution that combines a tree-like representation with a pseudo-dating scheme to provide an efficient and expressive means to deal with the problem

Plans as structured networks of hierarchically and temporally related case pieces

This paper describes a representation of plan cases as a structured set of goals and actions. These goals and actions are the unit pieces that form a case. These case pieces are related each other by hierarchical and temporal links (explanations) forming a tree-like network. We give importance not just to explicit links, i.e., links between case pieces which are concretely known, but also to implicit ones, i.e., possibly unknown links between case pieces. Each case piece is explained by antecedent links and explains other case pieces by consequent links. The retrieval of a case piece is mainly guided by its links and by its surrounding case pieces. Our concept of case piece usefulness is briefly explained. We discuss the benefit of reusing and directly accessing small case pieces from multiple cases for improving the Case-Based Reasoning (CBR) systems’ capability and efficiency to solve problems. We explain the importance of stepwise refinement in plan cases and also the role that temporal representation can take in the meaningful and coherent construction of planning problem solutions. An application in musical composition domain is presented. We also show how a musical composition task can be treated as a planning task

Experimental study of a similarity metric for retrieving pieces from structured plan cases: its role in the originality of plan case solutions

This paper describes a quantitative similarity metric and its contribution to achieve original plan solutions. This similarity metric is used by an iterative process of piece retrieval from structured plan cases. Within our approach plan cases are tree-like networks of pieces (goals and actions). These case pieces are ill-related each other by links (explanations). These links may be classified as hierarchical or temporal, antecedent or consequent, and explicit or implicit. Besides links, each case piece has also information about its properties (the attributes-value pairs), its hierarchical and temporal position in the case (the address), and about its constraints in the relationship with others (the constraints). The similarity metric computes a similarity value between two case pieces taking into account similarities between these case piece’s information types. Each time a problem is proposed, different weights are given to some of those similarities, with the aim of solving it with an original solution. This similarity metric is used by the system INSPIRER (ImagiNation taking as Source Past and Imperfectly REalated Reasonings). We illustrate the role of the similarity metric in the creativity of solutions, focusing specially their originality, with the presentation of the experimental results obtained in the musical composition domain, which is considered by us as a planning domain

Diagnóstico de anomalias em sistemas dinâmicos, com base em modelos qualitativos

Tese de doutoramento em Ciências da Engenharia (Engenharia Electrotécnica, especialidade Informática) apresentada à Fac. de Ciências e Tecnologia de Coimbr