Many researchers have addressed a great deal of methods to solve ILP problem for four decades [6]. Some of
them are non-efficient and some are too complicated for business use. Compared with many others, B&B procedure
which uses the enumerative divide-and-conquer technique is a better method. Besides, B&B has already
been in common use now. However, it might require an enormous amount of computation sometimes when
solving large-scale ILP problems. Although there are heuristics for enhancing the ability of B&B by guessing
which branch could lead to a quick solution, there is no solid theory that will always yield consistent results.
Hence, in this section, we propose a revised B&B method to solve IPL problem. Our method is to cut original
solution space into many subspaces using objective function before implementing B&B. It could narrow down
the feasible solution range. After labeling these subspaces based on the ‘‘distance’’ from objective function, we
can apply B&B procedure upon subspaces one by one. The nearest subspace will be the first one to be searched.
The first optimum solution we get in the nearest subspace is promised to be the optimum solution in all solution
space because of using objective function. The procedure of our proposed method is explained below: