A Model For Calculating Critical Chain Buffer Size Based On Information Entropy And GERT Network

In order to solve the schedule delays caused by uncertainty factors in the process of schedule management of engineering construction projects,the buffer size calculation model in critical chain project management(CCPM)is introduced to reasonably estimate the project duration.This paper takes the routes and networks formed between project processes as a whole as the research object,applies information entropy theory and CCPM,considers the influence of process factors,resource constraints,human behaviour factors and factors external to the project on the critical chain buffer;combines GERT network and quality loss transfer theory,measures the influence of combining different types of processes in the GERT network on the critical chain buffer,and considers the engineering project The research on the buffer calculation method was carried out considering the impact of quality loss values on the construction period.The main research and innovation points of the thesis are as follows:(1)Based on the information entropy theory,a model for calculating the buffer size of critical chain based on process entropy,resource entropy,human entropy and exogenous entropy is proposed,taking into account the influence of process safety time,process relay complexity,process technical complexity,resource tension,human complexity and exogenous influence on the buffer size.(2)Considering the impact of quality loss value on project duration,using the mean value of quality loss transmission as the project quality loss value,proposing the concept of project quality loss rate,introducing information entropy as a reasonable measure of project quality uncertainty,and constructing a GERT network quality entropy calculation model.(3)Based on the GERT network,the correction process of different logical processes and the method of correcting process duration are given,the uncertainty-based network is transformed into a deterministic network,and combined with the critical chain management method,the impact of the uncertainty of the increased merging process on the critical chain buffer is measured according to the information entropy theory,and a critical chain buffer size calculation model based on the GERT network is established.(4)The critical chain buffer size calculation model based on information entropy theory and GERT network is established,and the general method steps of the model are given and analyzed by calculation cases.The final research conclusion shows that the critical chain buffer size calculation model based on information entropy theory and GERT network constructed in this paper can reduce the project risk and shorten the construction period while ensuring a high probability of project completion,which provides a theoretical reference for CCPM in practical application,so as to achieve the goal of engineering project management more efficiently.