A bi-objective model for robust resource-constrained project scheduling

Abstract

A common problem which arises in project management is the fact that the planned schedule is 
often disrupted by several uncontrollable factors like additional time that might be required for 
rework and correction of detected defects. As a result, project managers are often unable to 
meet the promised completion dates. It is therefore vital to take into account such possible 
disruptions and their potential negative consequences at the project schedule design stage. In 
this paper, we address the issue of designing a project schedule which is not only short in time, 
but also less vulnerable to disruptions due to reworks and other undesirable conditions. To that 
aim, we introduce the concept of schedule robustness and we develop a bi-objective resource-constrained 
project scheduling model. We consider the objectives of robustness maximization along with 
makespan minimization. We develop a tabu search algorithm in order to generate an approximate 
set of efficient solutions. Several variants of the algorithm are tested and compared on a large 
set of benchmark problems. (c) 2004 Elsevier B.V. All rights reserved.