Normal Boundary Intersection Technique Zhenya Jia and Marianthi Ierapetritou Substantial benefits can be achieved through the use of optimization techniques in plant operations by improving the resource utilization at different levels of decision-making process. However, uncertainty exits in realistic manufacturing environment due to lack of accurate process models and variability of process and environment data. The presence of uncertainty can substantially reduce or eliminate the advantages of optimization approaches. Therefore, it is of great importance to develop systematic methods to address the problem of scheduling under uncertainty. There has been a substantial amount of work addressing the problem of design under uncertainty, while the issue of uncertainty in process operations and specifically in scheduling problems has received relatively little attention.