en Optimal design Optimal design پژوهشي Research <font size="2">In this paper we present a unified (probabilistic/possibilistic) model for resource-constrained project scheduling problem (RCPSP) with uncertain activity durations and a concept of a heuristic approach connected to the theoretical model. It is shown that the uncertainty management can be built into any heuristic algorithm developed to solve RCPSP with deterministic activity durations. The essence and viability of our unified model are illustrated by fuzzy examples presented in the recent fuzzy RCPSP literature.</font> Project scheduling; Stochastic scheduling; Fuzzy scheduling; Resource-constrained project; Heuristic algorithm; Simulation; Central limit theorem; Frequency histogram; Density function; Membership function 341 355 http://ijoce.iust.ac.ir/browse.php?a_code=A-10-1-70&slc_lang=en&sid=1 A. Csébfalvi 18003194753284600262 18003194753284600262 Yes