Heuristic approach for fuzzy activity time based critical path analysis of a project

Abstract

Scheduling a project is vcry typical ill each project performing al difTerenlloeations, To get the optimal balance between time and cost is a major concern to decision makers. O\~ing 10various uncertainlie~ ~llChas weather, prodlldivity level, inflation, human factors etc, during project exccution process, llme and cost of each activity may ,ary ~ignincantly. The relallonship between time and cost of thc activity is no longer a monotonously decrea8ing or increasing cune, hut rather the fuzzy nature. Therefore. deterministic model" 01"project scheduling are not emcient due to fuzziness ol"its variables. It 18\'~ry dillienlt to find lhe exact <;olutiotl of savings in hoth time and cost. To make such problem,>realistic, durations and co,ts 0 I"activities arc ehamctenzed by fuzzy set theory, In tbis study, triangular fuzzy numhers and the concept of a-cut method in Juzzy logic theory are employed to model the problem. a-cut method IS used as a measure of accepted risk level. Because ofNP-hard nature oflhe project scheduling problem with time and co<;!,Genetic Algonlhrn (GAl and SImulated Annealing (SA) based searching techniques are thcn adopted to proyide a trade-ofl'between implementatIon lime and total cost. The proposed modclleads the decision makers 10 choose the deSIred ,olulion under different values 01"a-l'Ut. hnal1y, laking a lest case, the perfonnanee ofGA and SA are b~nehmarked,