Time-Cost and Safety Trade-off in Project Scheduling under Uncertainty

Abstract

Abstract The aim of this study is to find a balance between cost, time, and fuzzy safety constraints in project scheduling. The objective is to minimize both the duration and the cost of the project while maintaining the safety standards within acceptable limits. Appropriate attention to safety can lead to increased customer satisfaction. By optimizing significant objectives such as cost and time, along with other project objectives like safety, project managers can deliver superior-quality projects. The existence of multiple factors that could potentially jeopardize project safety significantly impacts initial managerial estimates, and unforeseen changes may arise. Thus, it is crucial to consider the impact of safety on project scheduling, particularly when juggling multiple project objectives. Most real-world optimization problems are more complex and challenging to solve than those solvable through exact methods. Metaheuristic algorithms are typically employed to address NP-hard problems. In this study, we utilize the NHGA metaheuristic algorithm, proving to be more efficient than the classic genetic algorithm. As safety factors in project realms are often uncertain, we employ fuzzy number theory and linguistic variables to measure safety and account for the project manager's risk tolerance.