Fuzzy Comprehensive Evaluation Of Schedule Risk Based On PERT

Schedule control is one of the three project targets that are investment, schedule and quality. Time delay would cause the waste of human, financial and material resources and it is easy to produce quality problem, schedule management has became the core issue of the engineering project management. Uncertain factors of project is in the dynamic changing, thanks to lagging information, progress management need to accurately predict possible risks in future, accordingly, to make reasonable schedule risk evaluation is of great significance.Schedule risk evaluation is to describe the uncertainty of schedule risk with mathematical methods. With the birth of fuzzy system theory, the description of uncertainty of schedule risk has expanded from the classical probabilistic description to fuzzy description, and PERT (Program Evaluation and Review Technique) and Fuzzy Comprehensive Evaluation theory respectively are important separately probabilistic tool and fuzziness tool.When evaluation of schedule risk by Fuzzy Comprehensive Evaluation theory, risk factors are determinated based on the whole target of project period, but engineering project construction period is formed of varieties of activities, so this risk factors set is too generalized,and it can't refelect the difference of different variety of activities. On the basis of previous studies, on the one hand,this paper discusses the schedule risk factors set, point out schedule risk is the comprehensive reflection of all kinds of uncertainty, all levels of risk factors set can be determined through analyzing the uncertainty of all kinds of activities, and this standpoint is different from the generalize one,On the other hand, this paper discusses the MCS(Monte Carlo Simulation) of PERT, to expound and redefine the ACI(Activity Cruciality Index) of activity,and the ACI can reflect the influence degree of the uncertainty of activities on schedule risk. At last, based on two hierarchical Fuzzy Comprehensive Evaluation model, this paper analyzes the uncertainty of all kinds of activities, and ACI (Activities Critical Index) is used to determine the influence degree of the uncertainty of activities on schedule risk,to build the schedule risk evaluation model. Program is compolied by Matlab, and an engineering project is used to confirm this model.