A Cooperative-Architecture Expert System for Solving Large Time/Travel Assignment Problems

In this paper, we consider the problem of assigning tasks to operators according to a large set of constraints that include time sensitivity and travel optimization. Our practical instance of this problem combines computational complexity (scheduling the tasks for one technician is NP-hard and little is known about getting a solution [CK92]) and size (around 20000 tasks stored in a database). We present a solution that has been successfully implemented and tested, which we describe as an expert system where expertise is applied to constraint satisfaction. By combining a constraint solver and a rule-based domain expert, we have obtained a satisfactory level of efficiency while keeping the flexibility and extensibility of a constraint-based approach.