## 4 Experiment
### Verification Experiment of the DS Using BO  
The BO DS verification experiment was conducted under Medium Load conditions over a total of 10 iterations, with 17 repeated tests per iteration. Through this, we conducted a total of 170 tests and were able to optimize the UBT control specifications for a single load condition. In the optimization process, the DS value was used as the objective function, and constraints were set so that the Time Fail Count and Max Vibration (Max Tub Vibration) Fail Count were zero. Finally, the ninth UBT condition was selected as the control specification. This method could be applied to other load conditions in the same way to develop UBT control specifications. Although some variability existed in the results for each load condition, we were able to optimize the UBT control specifications within a maximum of 400 tests. Figure 6 shows the changes in the maximum and average entry time, which is the dehydration entry time, according to the test iterations in the BO optimization test results. The entry time should be minimized because a shorter time can reduce the overall washing cycle time. The \(X\)-axis represents the test stages (Initial, 1 st, 2 nd,..., 9 th), and the \(Y\)-axis indicates the entry time in seconds (s). Entry Time Max is shown as a solid line. Starting from a very high value in the initial stage, it showed significant volatility--decreasing rapidly at the beginning, then increasing, and finally converging while the overall volatility significantly decreased. Entry Time Avg is represented by a dotted line. The average entry time started at a low level in the initial stage and maintained a relatively constant value afterward. Although there was a slight increase in the fourth test, it gradually decreased, maintaining a generally stable trend without significant fluctuations. This result confirms that while the Entry Time Max performance can change rapidly in the early stages of the BO optimization, it decreases with repeated test iterations. The average value of the entry time showed a stable decreasing trend according to the test iterations. Figure 7 shows the changes in the maximum and average Max Vibration according to the test iterations in the BO optimization test results. Max Vibration is the vibration value of the washing tub, which should be minimized as it adversely affects noise and product reliability. However, it is in a trade-off relationship with the entry time. Figure 6: Entry time trends by test iteration. Max Vibration Max is shown as a solid line. The maximum value of Max Vibration showed a decreasing trend in the initial stages, then increased sharply in the fifth test, and decreased again towards the end. This result indicates that, while the Max Vibration Max performance may exhibit volatility during BO optimization, it successfully meets the DS target value in the end. The average value of Max Vibration did not show any significant changes according to the test iterations. By the ninth BO test iteration, the Entry Time Max and Max Vibration Max values had decreased to satisfactory levels. This result indicates that a dehydration control specification that satisfies the dehydration time and maximum vibration was set. It is evident from the fourth and fifth tests that the Entry Time Max and Max Vibration Max have a clear trade-off relationship. Figure 8 visualizes the optimization process of the UBT control specifications that satisfy the objective function and constraints through repeated test iterations. The \(X\)-axis represents the test iterations (Initial to 9 th iteration), and the \(Y\)-axis shows the DS performance indicator and the constraints counts for Time Fail Count and Max Vibration Fail Count. In this experiment, one DS and two constraints were used to measure the optimization of the control specifications. The DS, represented by a black solid line with circular markers, serves as a comprehensive performance evaluation indicator that takes both the entry time (\(Z_{t}\)) and vibration magnitude (\(Z_{o}\)) into account.