A new hybrid procedure that combines genetic operators to existing heuristics is proposed to solve the Quadratic Assignment Problem (QAP). Genetic operators are found to improve the performance of both local search and tabu search. Some guidelines are also given to design good hybrid schemes. These hybrid algorithms are then used to improve on the best… (More)
Solving the nurse scheduling problem properly has a great impact on nurses' working conditions which are strongly related to the level of quality of health care and recruiting of qualified personnel. In this paper, a multi-objective approach is shown to be a very flexible tool for modeling this problem. Hence, it could be used in several specific contexts.… (More)
A generalized fractional programming problem is specified as a nonlinear program where a nonlinear function defined as the maximum over several ratios of functions is to be minimized on a feasible domain of ~n. The purpose of this paper is to outline basic approaches and basic types of algorithms available to deal with this problem and to review their… (More)
We consider a generalization of a linear fractional program where the maximum of finitel3 many linear ratios is to be minimized subject to linear constraints. For this Min-Max problem a dual in the form of a Max-Min problem is introduced and duality relations are established.