A new heuristic for a single machine scheduling problem with set-up times

This paper examines the problem of scheduling jobs on a single machine with set-up times. The jobs are divided into mutually exclusive classes and a set-up task is required when processing switches from a job of one class to a job of another class. The set-up times are assumed to be sequence independent. A number of necessary conditions for a schedule to minimize mean flow time have previously been stated, but do not uniquely define the optimal solution, and the problem is apparently NP-complete. The authors propose a new polynomial-time heuristic, based on these conditions, and compare its performance with some existing heuristics.