Integration of Fuzzy Logic and QFD for Critical Chain in Project Scheduling with Uncertainties

This work aims at integrating fuzzy logic and quality function deployment (QFD) technique to determine the critical chain in a project with uncertainties. The degree of fuzziness of every activity in a project is defined and calculated by QFD so as to (1) evaluate the effects of project uncertainties, (2) select adaptively the fuzzy logic model, and (3) calculate the buffer time of the critical chain. The example of a project with 11 activities facing 6 uncertainties: project time limit, activity begin time, budget, manpower, technical difficulty, and facility requirement is applied to demonstrate the effectiveness of the model integrating fuzzy logic and QFD. Analysis shows that project scheduling by this proposed integration is superior to that by Project Evaluation and Review Technique (PERT) and by the conventional critical chain method. Not only the scheduling is more efficient, but also the buffer time in critical chain can be systematically determined to accommodate the uncertainties.