# PSO-SVM Based Performance-Driving Scheduling Method for Semiconductor Manufacturing Systems
## 4 Empirical Study
### Experimental Results
#### 4.3.3 Comparisons  
We ran three more simulation tests that were only based on equipment-related performances (EU_P and EU_O), fab-wide performances (MOV and PR), and wafer-related performances (PCSR and ODR) to further highlight the impact of the \"performance-driving\" design. Figure 9 presents the differences in the structure among the above three systems and the system \"driven by all six selected performances\", \"driven by equipment-related performances\", \"driven by fab-wide performances\", and \"driven by wafer-related performances\"; they differed only in the input of the parameter optimization model. 1. Equipment-related performance driving We recorded tens of experiments' results with different dispatching parameters to avoid contingency. The results of equipment-related performance driving are shown in Figure 10. From Figure 10, we can draw the following conclusions:  
* Compared to CDR, the proposed scheduling method with equipment-related performance driving improved MOV, PR, EU_P, EU_O, PCSR, and ODR by 8.56%, 4.18%, 10.65%, 10.08%, 6.64%, and 7.28%, respectively;
* Performances changed with the change of dispatching parameters;
* The proposed scheduling method with equipment-related performance driving could largely improve performances, especially in equipment utilization (equipment-related performances). 2. Fab-wide performances driving Similarly, we recorded tens of experiments' results with different dispatching parameters to avoid contingency. The results of fab-wide performance driving are shown in Figure 11.  
Figure 9: Structure of different performance-driving. From Figure 11, we can draw the following conclusions:  
* Compared to CDR, the proposed scheduling method with fab-wide performance driving improved MOV, PR, EU_O, EU_P, PCSR, and ODR by 8.84%, 2.98%, 8.26%, 8.64%, 6.68%, and 6.42%, respectively;
* Performances changed with the change of dispatching parameters;
* The proposed scheduling method with fab-wide performance driving could largely improve performances, especially in MOV and PR (fab-wide performances). * Wafer-related performances driving Similarly, we recorded tens of experiments' results with different dispatching parameters to avoid contingency. The results of wafer-related performance driving are shown in Figure 12.  
Figure 11: Comparisons between CDR and the scheduling method with fab-wide performance driving. Figure 10: Comparisons between CDR and the scheduling method with equipment-related performance driving. From Figure 12, we can draw the following conclusions:  
* Compared to CDR, the proposed scheduling method with wafer-related performance driving improved MOV, PR, EU_O, EU_P, PCSR, and ODR by 7.55%, 4.13%, 7.22%, 7.23%, 7.37%, and 8.26%, respectively;
* Performances changed with the change of dispatching parameters;
* The proposed scheduling method with wafer-related performance driving could largely improve performances, especially in PCSR and ODR (wafer-related performances). * Further Discussion  
To clarify the distinction among different performance-driving, we recorded the simulation results of CDR, scheduling methods with fab-wide performance-driving, equipment-related performance-driving, wafer-related performance-driving, and with all six selected performance-driving. Simulation results and normalization results are shown in Table 8 and Figure 13, respectively. From Table 8 and Figure 13, we can draw the following conclusions:  
* Compared to CDR, the proposed scheduling method improved MOV, PR, EU_O, EU_P, PCSR, and ODR by 7.85%, 5.11%, 8.76%, 8.14%, 6.60%, and 7.33%, respectively. This can illustrate the usefulness and effectiveness of \"performance driving\" and \"feedback mechanism\";  
Figure 12: Comparisons between CDR and the scheduling method with wafer-related performance driving.