Balancing of simple assembly lines under variations of task processing times

One of the simple assembly line balancing problems (SALBPs), known as SALBP-E, is considered. It consists in assigning a given set V={1,2,??,n} of elementary tasks to linearly ordered workstations with respect to precedence and capacity restrictions while minimizing the following product: number of used workstations × working time on the most loaded one. The stability of feasible and optimal solutions for this problem with regard to possible variations of the processing time of certain tasks is investigated. Two heuristic procedures finding a compromise between the efficiency and the considered stability measure of studied solutions are suggested and evaluated on known benchmarks.     

Robust balancing of straight assembly lines with interval task times

This paper addresses the balancing problem for straight assembly lines where task times are not known exactly but given by intervals of their possible values. The objective is to assign the tasks to workstations minimizing the number of workstations while respecting precedence and cycle-time constraints. An adaptable robust optimization model is proposed to hedge against the worst-case scenario for task times. To find the optimal solution(s), a breadth-first search procedure is developed and evaluated on benchmark instances. The results obtained are analysed and some practical recommendations are given.     

Equipment Location in Machining Transfer Lines with Multi-spindle Heads

The considered problem appears when a machining line must be configured. It is necessary to define the number of workstations and the number of spindle heads at each workstation to be put in the line in order to produce a given part. This problem is known to be $\mathcal{NP}$ -hard and, as a consequence, the solution time increases exponentially with the size of the problem. A number of pre-processing procedures are suggested in this article in order to decrease the initial problem size and thus shorten the solution time. A new algorithm for calculating a lower bound on the number of required equipment is also presented. A numerical example is given.     

Integer knapsack problems with profit functions of the same value range

4OR - Integer knapsack problems with profit functions of the same value range are studied. Linear time algorithms are presented for the case of convex non-decreasing profit functions, and an...