Simultaneous optimization of classical objectives in JIT scheduling

Just-in-time production models have been developed in recent years in order to reduce costs of diversified small-lot productions. The methods aim at maintaining the production rate of each type of part as smooth as possible and therefore holding small inventory and shortage costs. Different ways of measuring the slack between a given schedule and the ideal no-inventory no-shortage production have been considered in the literature. This paper compares the three most studied objective functions and refutes several conjectures that have been formulated in the last few years.