Minimizing activity exposures in project scheduling under uncertainty

Abstract

We propose a model to solve a project scheduling problem where resource assignments and activity schedules need to be determined to achieve a set of due-date requirements as well as possible. The concept of activity duration tolerance levels is introduced to describe the longest activity durations over which the due-dates are guaranteed to be achieved. Based on this, we propose a due-date achievement model using a proposed performance measure termed as the activities exposure level, which accounts for the total amount of durations exceeding tolerance levels for a given scheduling solution. We describe various properties and characteristics of the proposed scheduling optimization model and its practical implications. We show that the associated stochastic scheduling problem with resource constraints can be equivalently computed as the solution of a modest-sized mixed-integer linear program using the sample average approximation approach. Computational results show that our proposed models perform well when compared to different standard approaches across various performance measures.