I. Introduction
A computational grid [1] is the term adopted for infrastructure that enables the increase in computation. It provides inexpensive and consistent access to high-end computational resources. To achieve the promising potentials of computational grids, job scheduling is an important issue to be considered. The task scheduling problem has been demonstrated to be a NP-hard optimization problem because of complex characteristics of Grid. So there is a need of an effective job scheduling technique for solving complex computational problems found in grid environment.