In this paper, the beam search technique is applied to resource constrained project
scheduling where there is a single renewable resource to consider. Such projects occur
frequently in practice: such as use of labor in construction projects, or constraints on
number of programmers to carry out a software project. Usually the manpower needs
are estimated in units such as work-hours or work-days. The multi-mode consists
essentially of how many people can be employed to finish an activity. This problem is
also called the discrete time/resource trade-off problem. The beam search employs a
truncated breadth-first search tree, where all the choices are evaluated at each node, but
only a limited number of the choices are selected at each level for further search. A
number of evaluation techniques are presented for employment within the beam search
heuristic. Computational results are presented.