# Call Redistribution for a Call Center Based on Speech Emotion Recognition
## 4 Simulation and Experimental Results
New waiting time is calculated for each caller based on the new position in redistributed caller's queue. Accordingly, new waiting time for every emotion class is evaluated. Table 2 shows the average waiting time which a caller will spend if his/her call is among three calls received at the same moment while all operators are busy, before and after application of SER and call redistribution. It can be observed that there is a significant waiting time reduction for callers recognized as being in a state of fear: initially, they were waiting for about 2 min 40 s, and after SER and the proposed call redistribution they had to wait only 8 s. In the case of an angry caller, there is also a noticeable waiting time reduction: the initial waiting time was 2 min 19 s and after redistribution only about 1 min. In the case of a sad caller, there is little time saving expressed in few seconds: the initial waiting time was 2 min and after redistribution reduced to 1 min 45 s. Regarding neutral and joyful emotional states of the caller, there is an increase in waiting time after SER and call redistribution: about 1 min increased waiting time for a neutral caller and about 2 min for a joyful caller. This increase was expected as the redistribution always places callers with these emotions at the end of callers' queue. The average waiting time which a caller will spend if his/her call is among five calls received in a short period of time while all operators are busy, before and after the application of the proposed algorithm, is shown in Table 3. In the case of fear as the first in emotion ranking, there is the biggest and significant decrease in waiting time: from 4 min 17 s to 25 s after SER and redistribution. There is also a significant decrease in waiting time for angry callers: from 4 min 36 s to 1 min 57 s.  
Unlike the experiment with three calls at the same time, in the experiment with five calls, callers recognized as being sad have achieved nearly 1 min shorter waiting time after SER and redistribution. In the case of a neutral state, the waiting time is increased for about 1 min. For callers recognized as being joyful, the increase is larger and amounts to about 4 min. Table 4 shows the average waiting time which a caller will spend if his/her call is among 7 calls received simultaneously, i.e., in a short period of time while all operators are busy. As in two previous experimental settings, three emotions ranked as the priority one (fear, anger and sadness) have a significant decrease in waiting time. Calls featuring fear have the biggest waiting time reduction: it amounts to about 5 min 40 s. Calls featuring anger have achieved 2 min 20 s reduction in waiting time. In the case of a sad caller, the achieved decrease in waiting time is about 1 min. It can be observed that neutral and joyful callers have an increase in waiting time: 2 min 37 s and 5 min 30 s, respectively. \begin{table}
\begin{tabular}{c c c} \hline
**Emotion** & **without the Proposed Algorithm [min][s]** & **after Application of SER and Call Redistribution [min][s]** \\ \hline fear & 2:43 & 0:08 \\ anger & 2:19 & 1:01 \\ sadness & 2:00 & 1:45 \\ neutral & 2:09 & 3:07 \\ joy & 1:56 & 4:07 \\ \hline \end{tabular}
\end{table} 
Table 2: Average waiting time when 3 calls are received simultaneously while all operators are busy. \begin{table}
\begin{tabular}{c c c} \hline
**Emotion** & **without the Proposed Algorithm [min][s]** & **after Application of SER and Call Redistribution [min][s]** \\ \hline fear & 4:17 & 0:25 \\ anger & 4:36 & 1:57 \\ sadness & 4:49 & 3:56 \\ neutral & 4:07 & 5:13 \\ joy & 3:24 & 7:34 \\ \hline \end{tabular}
\end{table} 
Table 3: Average waiting time when 5 calls are received simultaneously while all operators are busy.