# Project Robust Scheduling Based on the Scattered Buffer Technology
## 5 Experimental Analysis
### Analysis of Experimental Results
#### 5.2.1 Impact of Scheduled Due Date on the Robust Schedule  
When \(\sigma=0.3\), three groups of problems (\(J10\), \(J20\) and \(J30\)) are tested, respectively. Table 1 shows the simulation results under various algorithms of the above three groups of problems in different due dates. (1) With the extension of due date:  
1 in terms of solution robustness, the solution robustness of UAS increase gradually the same as RFDFF and STC, namely the larger the value of \(SP\), the smaller the value of \(SC\) is. When the value of scheduled due date is relatively smaller, namely when the duration is relatively tight, the value of \(SP\) is smaller, but the value of \(SC\) is larger, which is because the buffer size is under control and the number of activities that can be given a buffer area is less, thus the buffer that has been set is not enough to improve the robustness of the schedule. When the due date is extended, that is, when the duration is relatively loose, a larger buffer can be set, and more buffers can be set in front of more activities. The value of \(SP\) will increase, the value of \(SC\) will be smaller, and so the robustness of the schedule can be improved. 2 In terms of quality robustness, the timely project completion probability (\(TPCP\)) of the project in UAS will gradually increase with the extension of the completion time. This indicates that, when the completion time is extended, UAS plays a role in protecting the stability of each activity's start time as well as protecting the deadline of the project according to the schedule. However, with the extension of \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Problem**} & **Robustness** & \multicolumn{3}{c}{\(Dust=1.05\times C_{\min}\)} & \multicolumn{3}{c}{\(Dust=1.10\times C_{\min}\)} & \multicolumn{3}{c}{\(Dust=1.20\times C_{\min}\)} \\ \cline{3-10}  & **Metrics** & **RFDFF** & **STC** & **UAS** & **RFDFF** & **STC** & **UAS** & **RFDFF** & **STC** & **UAS** \\ \hline \multirow{4}{*}{\(J10\)} & SP & 0.7449 & 0.7730 & 0.7977 & 0.8117 & 0.8165 & 0.8401 & 0.8968 & 0.8675 & 0.9017 \\  & SC & 24.8486 & 24.2272 & 19.2713 & 19.5327 & 18.6960 & 14.0884 & 10.1944 & 14.1227 & 7.1140 \\  & TCP & 0.6237 & 0.6281 & 0.6251 & 0.7417 & 0.7454 & 0.7416 & 0.8661 & 0.8886 & 0.8864 \\  & APL & 33.1894 & 33.1750 & 33.1526 & 33.1488 & 33.1196 & 33.1661 & 33.1488 & 33.1555 & 33.1587 \\ \hline \multirow{4}{*}{\(J20\)} & SP & 0.6756 & 0.7006 & 0.7104 & 0.7502 & 0.7654 & 0.7709 & 0.8592 & 0.8365 & 0.8546 \\  & SC & 110.7461 & 103.0997 & 89.5769 & 78.7674 & 72.5052 & 64.5783 & 39.8592 & 48.3712 & 35.2247 \\  & TCP & 0.5080 & 0.5030 & 0.5124 & 0.6698 & 0.6776 & 0.6678 & 0.8830 & 0.8801 & 0.8833 \\ \hline \multirow{4}{*}{\(J30\)} & APL & 54.5441 & 54.5768 & 54.4076 & 54.5441 & 54.3327 & 54.4847 & 54.5441 & 54.4815 & 54.4659 \\  & SP & 0.6461 & 0.6858 & 0.6622 & 0.7416 & 0.7752 & 0.7465 & 0.8730 & 0.8769 & 0.881 \\  & SC & 205.3720 & 153.3981 & 154.0193 & 145.3232 & 114.7046 & 115.1642 & 72.6573 & 70.4379 & 67.3279 \\  & TCP & 0.4012 & 0.4149 & 0.3956 & 0.6064 & 0.6151 & 0.6021 & 0.8846 & 0.8857 & 0.8790 \\  & APL & 69.9003 & 69.8646 & 69.8022 & 69.9003 & 69.9853 & 69.9593 & 69.9003 & 69.8613 & 69.9458 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The impact of due date on the robustness when \(\sigma=0.3\). the due date, the average project length (_APL_) in UAS, RFDFF and STC basically remain unchanged, which is because the three groups of activity durations are all generated under the variance \(\sigma=0.3\), and the average project length (_APL_) is less affected by the extension of the due date. (2) With the increment of the project scale:  
1 In terms of solution robustness, when the duration is relatively tight, UAS, RFDFF and STC are the same: the solution robustness presented by value of \(SC\) and \(SP\) is gradually decreasing.