Sequential decisions under uncertainty in the R&D project selection problem

In most cases, the R&D project selection problem is concerned with how to evaluate and identify the best subset of projects under some resource constraints. In this paper, we consider the sequential decision problem of optimally sequencing a set of projects which must be undertaken sequentially over time. We derive the optimal ordering strategy for two special cases, (1) a series system of tasks in which the selection process is terminated as soon as one of the tasks is failed, and (2) a parallel system of alternatives in which the selection process continues until any of the alternatives is completed successfully. We further consider the precedence restriction in a series system of tasks which specifies that, for some technological or budgetary constraints, a certain task must be undertaken before another. In a parallel system of alternatives, we also investigate the availability condition under which a certain alternative will not be available if not selected within a certain period of time