Research On Project Schedule Management Based On Z-number Critical Chain

With the architecture function and structure of the project item becoming increasingly complicated,as well as uniqueness and diversity of project item becoming increasingly remarkable,which makes the management of the project schedule more difficult.However,traditional progress management techniques —CPM and PERT,due to its shortage,are more difficult to adapt to practical situation of modern project.It is important to seek for a scientific and reasonable progress control method.Targeted the shortages of traditional progress management technique,management master Goldratt proposes a new progress management method,critical chain method.Compared with traditional methods of progress management,the critical chain method takes into account both the dual constraints of resources and time,and absorbs the negative effects of risk factors through the setting of buffers.In addition,critical chain method will also consolidate some research results in the field of organizational behavior to progress management methods,and same time consideration of people's behavior and management art,to avoid such as the student syndrome,Parkinson's law and other causes of delay in progress during project management processes.Although the critical chain method own many advantages on progress control,there are still a lot of controversy in its duration estimates,buffer size calculation and other aspects.Based on the basis of consulting domestic and foreign research results,targeted project item,there are improvements in critical chain project duration estimation,buffer size calculation and other aspect.Firstly,comparing several traditional process management methods,paper analyzes the problems and reasons of traditional process management methods application in modern project,as well as critical chain for improvement of traditional method.Then,introducing the theory of Z-number that indicates uncertainty of working procedure duration,on this basis,and taking into account the different characteristics of different projects and procedure.Paper proposes in the same time the impact that risks have on buffer form working procedure level and project level,by using the reliability of duration estimate value that ascertains working procedure risk and resource tension of project overall level that indicates project risks.Thus the buffer size calculation model is established that comprehensively considers the working procedure risks,project risks,and resources risk.Result shows that the improved model can reduce the negative effects of risk factors on the project.Setting the buffer time can not only effectively protect the project implementation,but also avoid waste of buffers.Finally,the feasibility of the proposed method is proved by case analysis,and compared with the existing buffer model from the perspective of theory and data,confirming the superiority and practicality of the improved model.