Toward an expert system for expressive musical performance

The development and implementation of an expert system that determines the tempo and articulations of Bach fugues are described. The rules in the knowledge base are based on the expertise of two professional performers. The system´s input is a numeric representation of the fugue. The system processes the input using a transition graph, a data structure consisting of nodes where data is stored and edges that connect the nodes. The transition graph recognizes rhythmic patterns in the input. Once the system identifies a pattern, it applies a specific rule or performs a procedure. System output consists of a listing of tempo and articulation instructions. To validate the expert system, its output was compared with versions of fugues edited by one of the two experts used in developing the system. In tests with six fugues, the expert system generated the same editing instructions 85 to 90% of the time.<>