Research On The Buffer Sizing Method In Critical Chain Project Management

Buffer is a important concept in critical chain project management, and we can eliminate uncertainties'influence on the implementation of project plan through setting and inserting buffer, ensuring project can finish in time. The most commonly used methods to decide the size of buffer are C&PM and RSEM. These two methods have both merits and demerits and it is difficult to apply them into practice because they ignore the characteristics of project and the degree of uncertainties. And other scholars also put forward some methods considering item features for computing the size of buffer, but the item features considered are very few, with no pertinency in the practical environment.This thesis sets buffer size from the angle of project uncertainty, identifies uncertain factors in the implementation of different projects including the project's own characteristic and the external environment factors firstly, then measures value of uncertainties and gives different weights with the method of fuzzy mathematics comprehensive judgment, put forward a new method for buffer sizing in line with the actual situations of project. Based on C++ language, the thesis designs and develops the Monte Carlo analogy simulation model, analyzing optimization effect of critical chain project management by utilizing time-limit for a project, completion rates of time-limit and buffer consumption as judgment standard. And the new method is compared with the existing methods, the results show that the new method for buffer sizing has many advantages over traditional methods for computing the size of buffer, in three aspects including time-limit for a project, completion rates of time-limit and buffer consumption, demonstrating that the method is feasible and practical. In light of above conclusions, this thesis points out three study directions for future—methods for buffer control,application areas of buffer management and multi-project management.