n South African Journal of Industrial Engineering - The discreet time, cost and quality trade-off problem in project scheduling : an efficient solution method based on CellDE algorithm : general articles

Volume 21, Issue 1
  • ISSN : 1012-277X



The trade-off between time, cost, and quality is one of the important problems of project management. This problem assumes that all project activities can be executed in different modes of cost, time, and quality. Thus a manager should select each activity's mode such that the project can meet the deadline with the minimum possible cost and the maximum achievable quality. As the problem is NP-hard and the objectives are in conflict with each other, a multi-objective meta-heuristic called CellDE, which is a hybrid cellular genetic algorithm, is implemented as the optimisation method. The proposed algorithm provides project managers with a set of non-dominated or Pareto-optimal solutions, and enables them to choose the best one according to their preferences. A set of problems of different sizes is generated and solved using the proposed algorithm. Three metrics are employed for evaluating the performance of the algorithm, appraising the diversity and convergence of the achieved Pareto fronts. Finally a comparison is made between CellDE and another meta-heuristic available in the literature. The results show the superiority of CellDE.

'n Balans tussen tyd, koste en gehalte is een van die belangrike probleme van projekbestuur. Die vraagstuk maak gewoonlik die aanname dat alle projekaktiwiteite uitgevoer kan word op uiteenlopende wyses wat verband hou met koste, tyd en gehalte. 'n Projekbestuurder selekteer gewoonlik die uitvoeringsmetodes sodanig per aktiwiteit dat gehoor gegegee word aan minimum koste en maksimum gehalte teen die voorwaarde van voltooiingsdatum wat bereik moet word. Aangesien die beskrewe problem NP-hard is, word dit behandel ten opsigte van konflikterende doelwitte met 'n multidoelwit metaheuristiese metode (CellDE). Die metode is 'n hibride-sellulêre genetiese algoritme. Die algoritme lewer aan die besluitvormer 'n versameling van ongedomineerde of Pareto-optimale oplossings vir voorkeurgedrewe besluitvorming. Uiteenlopende probleme word opgelos deur die algoritme. Drie verskillende waardebepalings word toegepas op die gedrag van die algoritme. Die resultate bevestig die voortreflikheid van CellDE.

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