英文摘要 |
In the theory of Critical Chain/Buffer Management (CC/BM), to protect the due-date promised to the customer from the variation in activity durations, the safeties associated with the critical activities are shifted to the end of the critical chain in the form of a project buffer. Moreover, feeding buffers are placed whenever a non-critical chain activity joins the critical chain. The most widely used buffer sizing methods are the cut and paste method (C&PM) and the root square error method (RSEM). Herroelen and Leus performed a full factorial experiment on a set of benchmark problems to test the CC/BM scheduling mechanism, and then reported that the C&PM may lead to a serious overestimation of the required buffer protection. From the results of this experiment, it can be also found that the project makespan highly depends on the resource tightness and the density of precedence. Therefore, Tukel et al. took these two factors into consideration, and then proposed two adjustment factors for the RSEM. However, their adjustment factors may lead to a significant and unnecessary expansion. To avoid the unnecessary expansion, in this paper, some revision to their adjustment factors are proposed. The new adjustment factors take the value 1 in cases that the resource is sufficient enough and the network is a chain. |