Fernando Von Zuben vonzuben@dca.fee.unicamp.br
State University of Campinas Faculty of Electrical and Computer Engineering
- UNICAMP/FEEC
Jτnatas Manzolli jonatas@nics.unicamp.br
State University of Campinas Interdisciplinary Nucleus of Sound Communication
UNICAMP/NICS
Extended Abstract
Evolution is now considered not only powerful enough to bring about
the biological entities as complex as humans and conciousness, but also
useful in simulation to create algorithms and structures of higher levels
of complexity than could easily be built by design. In the context of artistic
domains, the process of human-machine interaction is analyzed as a good
framework to explore creativity and to produce results that could not be
obtained without this interaction.
When evolutionary computation and other computational intelligence
methodologies are involved, every attempt to improve aesthetic judgement
we denote as ArTbitrariness, and is interpreted as an interactive iterative
optimization process. ArTbitrariness is also suggested as an effective
way to produce art through an efficient manipulation of information and
a proper use of computational creativity to increase the complexity of
the results without neglecting the aesthetic aspects [Moroni et al., 2000].
Our emphasis will be in an approach to interactive music composition.
The problem of computer generation of musical material has received
extensive attention and a subclass of the field of algorithmic composition
includes those applications which use the computer as something in between
an instrument, in which a user "plays" through the application's interface,
and a compositional aid, which a user experiments with in order to generate
stimulating and varying musical material. This approach was adopted in
Vox Populi, a hybrid made up of an instrument and a compositional environment.
Differently from other systems found in genetic algorithms or evolutionary
computation, in which people have to listen to and judge the musical items,
Vox Populi uses the computer and the mouse as real-time music controllers,
acting as a new interactive computer-based musical instrument. The interface
is designed to be flexible for the user to modify the music being generated.
It explores evolutionary computation in the context of algorithmic composition
and provides a graphical interface that allows to modify the tonal center
and the voice range, changing the evolution of the music by using the mouse
[Moroni et al., 1999].
A piece of music consists of several sets of musical material manipulated
and exposed to the listener, for example pitches, harmonies, rhythms, timbres,
etc. They are composed of a finite number of elements and basically, the
aim of a composer is to organize those elements in an esthetic way. Modeling
a piece as a dynamic system implies a view in which the composer draws
trajectories or orbits using the elements of each set [Manzolli, 1991].
Nonlinear iterative mappings are associated with interface controls. In
the next page two examples of nonlinear iterative mappings with their resulting
musical pieces are shown.The mappings may give rise to attractors, defined
as geometric figures that represent the set of stationary states of a non-linear
dynamic system, or simply trajectories to which the system is attracted.
The relevance of this approach goes beyond music applications per se.
Computer music systems that are built on the basis of a solid theory can
be coherently embedded into multimedia environments. The richness and specialty
of the music domain are likely to initiate new thinking and ideas, which
will have an impact on areas such as knowledge representation and planning,
and on the design of visual formalisms and human-computer interfaces in
general.
Above and bellow, Vox Populi interface is depicted, showing two nonlinear
iterative mappings with their resulting musical pieces.
References
[Manzolli, 1991]
J. Manzolli. Harmonic Strange Attractors, CEM BULLETIN, Vol. 2, No.
2, 4 -- 7, 1991.
[Moroni et al., 1999]
Moroni, J. Manzolli, F. Von Zuben, R. Gudwin. Evolutionary Computation
applied to Algorithmic Composition, Proceedings of CEC99 - IEEE International
Conference on Evolutionary Computation, Washington D. C., p. 807 -- 811,1999.
[Moroni et al., 2000]
Moroni, A., Von Zuben, F. and Manzolli, J. ArTbitration, Las Vegas,
USA: Proceedings of the 2000 Genetic and Evolutionary Computation Conference
Workshop Program GECCO, 143 -- 145, 2000.