Aspect-oriented music representation

Abstract

The composition of a musical work may be viewed as involving the exploitation, through various combinations, transformations and arrangements, of a finite set of compositional processes and musical materials. As a consequence, combinatorial and transformational processes and musical materials across various musical dimensions tend to be scattered throughout a musical work. Although the processes involved in music composition vary widely between composers, and indeed between works, in general these processes tend to be iterative, with the composer creating and revising musical materials within and between different musical dimensions and concerns. When musical materials are modified, related musical structures must also be updated, in order to maintain musical coherence. However, in general, the relationships that exist between musical materials are not explicitly notated. Although for many composers this process may be unconscious, we hypothesize that tools for identifying, creating, organising, modifying and manipulating such related structures explicitly would have numerous applications for composers, teachers and analysts. The aim of the research described in this thesis is to find ways in which Aspect Oriented Programming (AOP), and cognate techniques, may be used to facilitate the development of computer systems that support musical composition by assisting in the separation, organisation and combination of musical concerns. We investigate the semantics of crosscutting within a musical context and use this to evolve an Aspect Oriented Music Representation (AOMR), and a concrete proof-of-concept implementation of AOMR called AspectMusic. AOMR demonstrates how two different, current approaches to AOP, namely symmetric and asymmetric, can be usefully applied to the separation, composition and conditional modification of musical structures. We also describe an approach, called Composition History, which provides a detailed history of the symmetric composition operations that have been applied to a structure and makes this information available within the asymmetric framework. In this way, details of the provenance of any given musical event may be used as part of the pointcut expression within asymmetric AOMR aspects. Additionally, we demonstrate a logic reification of AOMR events, including composition history, which permits declarative pointcut expressions.