1. PhD thesis: Contributions to complex project and machine scheduling problems download


    Scheduling problems are, generally speaking, the problems of allocating scarce resources over time to perform a given set of jobs (activities). Due to its practical relevance, the field of scheduling has been one of the most studied fields since the early days of Management Science and Operation Research. Within the field of scheduling, many sub-fields have been studied during the last century, among which project scheduling and single machine scheduling have received special attention. In this dissertation, we mainly contribute in these two mentioned sub-fields. As such, this dissertation includes two parts: the first part includes contributions to complex project scheduling problems and the second part includes contributions to a single machine scheduling problem. In the first part, we contribute (i) by introducing an integrated proactive and reactive resource-constrained project scheduling problem and by proposing several models that can solve the introduced problem, (ii) by presenting two very important classes of reactions and by investigating their relevance in optimal proactive and reactive policies and (iii) by developing a novel branch-and-bound algorithm that solves instances of chance-constrained resource-constrained project scheduling problem. In the second part, we contribute (i) by introducing a generic single machine scheduling problem where the objective is to minimize the total weighted tardiness penalty and solutions are subject to both time-window constraints and precedence constraints, (ii) by proposing several lower bounding schemes for the introduced problem and by investigating the theoretical relevance and the complexities of the proposed lower bounds and (iii) by presenting two branching schemes and a number of dominance rules that combined construct two branch-and-bound algorithms that can solve instances of the introduced problem.