Canon is both a notation for musical scores and a programming language. Canon offers a combination of declarative style and a powerful abstraction capability which allows a very high-level notation for sequences of musical events and structures. Transformations are operators that can adjust common parameters such as loudness or duration. Transformations can be nested and time-varying, and their use avoids the problem of having large numbers of explicit parameters. Behavioral abstraction, the concept of making behavior an arbitrary function of the environment, is supported by Canon and extends the usefulness of transformations. A non-real-time implementation of Canon is based on Lisp and produces scores that control MIDI synthesizers. Introduction Canon is a computer language designed to help composers create note-level control information for hardware synthesizers or synthesis software. Canon was motivated by my need for a simple yet powerful language for teaching second-semester stud...

We propose an extension of Smalltalk with finite-domain constraint satisfaction mechanisms. Our system, called BackTalk, allows the definition of constraints over arbitrary Smalltalk objects, and implements efficient algorithms for constraints satisfaction. We exemplify the use of BackTalk on a problem known to be complex, automatic harmonization. We outline several previous attempts to solve the problem with similar mechanisms, and stress on their inefficiencies, mainly the lack of structure of domain objects. We propose to solve the problem by a combination of constraints and objects that fully benefits from object structures. This is achieved in practice by separating the constraint satisfaction process in two steps. By comparison, our system yields excellent results, both in term of efficiency and readability. We discuss the generality of our approach to problems involving numerous and heterogeneous object structures. Key-words: constraints, finite-domain constraint satisfaction, ...

ABSTRACT. We describe a representation framework for temporal objects and reasoning in the MusES system. The framework is claimed to be use-neutral within the context of tonal music. It is based on the use of an object-oriented programming language, Smalltalk, and makes full use of two main representation mechanisms: class inheritance and delegation. We describe the kernel of the representation framework and explain the main design choices. We show how the kernel can be used and extended to represent important temporal concepts related to tonal music. The framework is validated by the realization of two substantial applications: an automatic analyser for chord sequences, and a simulator of jazz improvizations. 1.

We report here on current works on the MusES environment, designed for experimenting with various objectoriented knowledge representation techniques in the field of tonal harmony. The first layer of MusES is a repository of consensus knowledge about tonal harmony, including an explicit representation of enharmonic spelling, as well as representation of intervals, scales and chords that support standard computations. We give an overview of several systems built on top of MusES: a system for the analysis of jazz chord sequences, a system for the automatic generation of harmonizations, and a system that generates real-time jazz improvisations. We give an overview of MusES and its extensions and discuss several representation issues and their solutions in MusES. 1. Introduction: yet another Smalltalk music representation system Music analysis has long been a favorite domain for researchers in Artificial Intelligence. Within AI, ObjectOriented Programming (OOP) has traditionally been a fav...

Integrating constraint satisfaction techniques with complex object structures is highly desirable. Several libraries are now available to use algorithms off-the shelf and embed them in large object-oriented systems. However, the design of complex object + constraint problems is an open issue that severely limits the applicability of available libraries. We compare two radically different approaches in designing systems integrating objects and finite domain constraints. In the first approach, constraints are defined within classes and constrain attributes of the class, thereby introducing "partially instanciated " objects in the reasoning. In the second approach, constraints are defined outside classes, and constrain fully instanciated objects. We show that, for a particular class of problem, the second solution yields a simpler design while being more efficient. We exemplify our claims by comparing these two approaches on a hard object + constraint problem: four-voice harmonization of tonal melodies, seen as a representative complex configuration problem. 1.

Real-time systems are commonly regarded as the most complex form of computer program due to parallelism, the use of special purpose input/output devices, and the fact that time-dependent errors are hard to reproduce. Several practical techniques can be used to limit the complexity of implementing realtime interactive music and animation programs. The techniques are: (1) a program structure in which input events are translated into procedure calls, (2) the use of non-preemptive programs where possible, (3) event-based programming which allows interleaved program execution, automatic storage management, and a single run-time stack, (4) multiple processes communicating by messages where task preemption is necessary, and (5) interface construction tools to facilitate experimentation and program refinement. These techniques are supported by software developed by the author for realtime interactive music programs and more recently for animation. Although none of these techniques are new, the...

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ly, there is a mathematical function that maps beat numbers to time and an inverse function that maps time to beats. (Some special mathematical care must be taken to allow for music that momentarily stops, instantaneously skips ahead, or is allowed to jump backwards, but we will ignore these details.) One practical representation of the beat-to-time function is the set of times of individual beats. For example, a performer can tap beats in real time and a computer can record the time of each tap. This produces a finitely sampled representation of the continuous mapping from beats to time, which can be interpolated to obtain intermediate values. MIDI Clocks, which are transmitted at 24 clocks per quarter note, are an example of this approach. The Mockingbird score editor [Maxwell 84] interface also supported this idea. The composer would play a score, producing a piano-roll notation. Then, downbeats were indicated by clicking with a mouse at the proper locations in the piano roll score....

This paper presents the FORMES system developed at IRCAM to deal with the complexity of o