Research On Method For Estimating The Probability Of The Large-scale Project Completion Time Over Target Deadline

In the project schedule management,the probability of the project completion time over target deadline is one of the indicators to measure project schedule risk,and has important guiding significance.At present,the number of large-scale construction projects has increased significantly,but the existing methods still have the limitations(low calculation efficiency and low accuracy)in estimating the failure probability of large-scale project.Based on this,according to the characteristics of the schedule network of large-scale projects,this paper proposes an efficient novel numerical simulation algorithm to quickly and accurately estimate the failure probability of large-scale projects.In addition,to solve the difficulties in directly applying the proposed algorithm for o project managers and improve the application value of the proposed algorithm in practical project,based on the proposed algorithm,this paper also develops a Project Schedule Management Decision Support System(PSMDSS).The main research work and results of this paper are as follows:Firstly,considering the large number of paths in the schedule network of large-scale engineering projects,an efficient novel numerical simulation algorithm is proposed to estimate the probability of the project completion time over target deadline.The main ideas of the algorithm are as follows: firstly,reduce the scale of project schedule network path;Secondly,based on the simplified project schedule network path,the probability of project fail to be completed on schedule is estimated.Secondly,a novel numerical simulation algorithm is proposed to estimate the probability of the project completion time over target deadline for small-scale projects.Based on the idea of domain decomposition method,the algorithm regards the events that all paths in the project schedule network fail to be completed on schedule as a series of elementary failure events,and estimates the probability as the product of the sum of the probabilities of all basic failure events and the overlapping degree between basic failure events.Then,through the analysis of an example,it can be confirmed that the estimation result of the algorithm is accurate and the estimation efficiency is high.Thirdly,As for the problem of project schedule network reduction,this paper studies the simplification strategy for project schedule network.Based on this strategy,the huge paths in schedule network of large-scale engineering projects can be quickly reduced to a reasonable scale,and the reduced paths are representative paths that can be used to effectively estimate the probability of the project completion time over target deadline.Fourthly,this paper studies and designs the framework,system interface and functions of the PSMDSS.Then develops the system with MATLAB app designer as the development environment and Access database as the tool supporting information management.Finally,taking the estimation of the probability of fail to be completed within target deadline for an underground engineering project of a scientific research building as an example,this paper verifies the performance of the efficient novel numerical simulation algorithm.The results show that the estimation result of the algorithm is efficient and its estimated value is accurate.Moreover,compared with the Monte Carlo method,its estimation time is reduced by more than 99%.At the same time,the underground engineering project is used to test the developed PSMDSS.The results show that the system is feasible and practicable.