This paper addresses job shop scheduling problems with fuzzy processing time and fuzzy trapezoid or doublet due date. An efficient random key genetic algorithm (RKGA) is suggested to maximize the minimum agreement index and to minimize the maximum fuzzy completion time. In RKGA, a random key representation and a new decoding strategy are proposed and two-point crossover (TPX) and discrete cross...

All practical digital circuits are usually a mixture of combinational and sequential logic. Flip–flops are essential to sequential logic therefore fuzzy flip–flops are considered to be among the most essential topics of fuzzy digital circuit. The concept of fuzzy digital circuit is among the most interesting applications of fuzzy sets and logic due to the fact that if there has to be an ultimat...

Though many of the previous studies have been devoted to internal due date assignment in a wafer fabrication factory (wafer fab), very few among them considered the allowance added to a completion time forecast. In this way, the probability of on-time delivery is only about 50%. Methods based on confidence intervals generate completion time forecasts with very wide ranges and are not practical....

A method is described to assign product due dates for multistage assemblies with uncertain manufacturing and assembly process times. Earliest start times of operations are specified by a predetermined production plan and processing time distributions for operations are truncated at minimum processing times. The method systematically decomposes the complex product structures of multistage assemb...

The problem of scheduling groups of jobs on a single machine under the group technology assumption is studied. Jobs of the same group are processed contiguously and a sequence independent setup time precedes the processing of each group. All jobs have a common fixed due date, which can be either unrestrictively large or restrictively small. The objective is to minimize the total weighted earlin...

We propose a heuristic procedure that constructs a schedule for N jobs with stochastic processing times and a common due date on M parallel, identical machines. The criterion is the minimization of the total expected incompletion cost. A worst-case analysis for the ratio of the heuristic and optimal solutions is presented and a bound on the ratio is derived. The experimental results presented i...

The Due-Date Bargainer is a useful tool to support negotiation on due-dates between a manufacturer and its customers. To improve the computational performance of an earlier version of the Due-Date Bargainer, we present a new soft computing approach. It uses a genetic algorithm to nd the best priority sequence of customer orders for resource allocation and fuzzy logic operations to allocate the ...