The problem tackled in this paper deals with products of a finite number of triangular matrices in Max-Plus algebra, and more precisely with an optimization problem related to the product order. We propose a polynomial time optimization algorithm for 2 × 2 matrices products. We show that the problem under consideration generalizes numerous scheduling… (More)
W e consider a two-machine flowshop-scheduling problem with an unknown common due date where the objective is minimization of both the number of tardy jobs and the unknown common due date. We show that the problem is NP-hard in the ordinary sense and present a pseudopolynomial dynamic program for its solution. Then, we propose an exact-constraint approach… (More)
One of the critical problems in the call center industries is the staffing problem since they must face variable demands and because staff costs represent a major part of the costs of this industry. The problem of dimensioning a call center is modeled as a particular scheduling problem, where the objective is to minimize the weighted number of resources… (More)
We consider a single machine scheduling problems, where the machine is not available for processing jobs between a date s and a date t, and where each operation to schedule has one head and one tail. We propose a lower bound, upper bounds and a branch-and-bound algorithm. Computational experiences prove the efficiency of the bounds.