Gustavo Silva Semaan

An optimization approach applied to the optimal stratification problem

ABSTRACT A new optimization algorithm is presented to solve the stratification problem. Assuming the number L of strata and the total sample size n are fixed, we obtain strata boundaries by using an objective function associated with the variance. In this problem, strata boundaries must be determined so that the elements in each stratum are more homogeneous among themselves. To produce more homogeneous strata, this paper proposes a new algorithm that uses the Greedy Randomized Adaptive Search Procedure (GRASP) methodology. Computational results are presented for a set of problems, with the application of the new algorithm and some algorithms from literature.

Metaheuristic GRASP with path-relinking to the solution of the graph partitioning problem with capacity and connexity constraints

This work proposes new hybrids algorithms based in the Greedy Randomized Adaptative Search Procedure (GRASP) metaheuristic and Path-Relinking (PR) procedure for the solution of the Clustering Problem with Capacity and Connectedness Constraints. Computational results show the proposed methods to be competitive in relation to instances in the literature and to existing techniques.