Multi-resource-constrained discrete time-cost tradeoff with MOGA based hybrid method

This work focuses on solving multi-resource-constrained discrete time-cost tradeoff (MRCDTCT) problems in project scheduling using a novel methodology which hybridizes a heuristic with a multi-objective genetic algorithm - a hybrid MOGA. The proposed method is pertinent for the real world project scheduling where the resources are constrained, and where generation of complete Pareto-optimal front is essential for a decision-maker. Accordingly, the entire time-cost tradeoff (TCT) profile is identified, wherein the decision-maker basically makes a sequence of decisions, which optimizes the overall performance of the project in terms of time and cost by satisfying not only the precedence constraints but also the resource constraints. A MOGA, is devised to search for the optimal profile, and a heuristic is developed and hybridized with MOGA to ensure the availability of the resource requirements for each instance of the project schedule of MOGA by adjusting the start time of non-critical activities exploiting their float values. To demonstrate the efficacy of MOGA employed in this work, two standard test problems from the literature are attempted. The hybrid MOGA is employed to solve two test problems of TCT, one with a single resource constraint, and the other with three resource constraints. The results are also compared with those of exhaustive enumeration technique - the close proximity between these results validates the suitability and accuracy of hybrid MOGA to solve MRCDTCT problems.