## 4 Measurements and Testing of the Measuring System
### Network Load Testing
#### 4.3.3 Quality of Motion Mapping Using the Data Transmission Algorithm  
In the presented system, when optimizing network traffic, it is important to reduce the amount of transmitted data, while maintaining high-quality monitoring of individual sensor signals. In the algorithm described in Section 3, data from the accelerometer, gyroscope and magnetometer are averaged and then sent to the PC server. Additionally, the latest quaternion representing the rotation of the individual sensors is sent. This reduces the number of measurement points depending on the frame transmission frequency \(f_{T}\). In order to verify the quality of mapping the measurement signals, a series of tests was carried out with the use of the proposed algorithm. The research allowed to compare the reduced data received from the WSS and the complete measurement data from the MEMS sensors. The tests were preceded by the procedure of determining the threshold values (_TH1_, _TH2_, _TH3_).  
In order to determine the threshold values, measurements were performed with the participation of three volunteers. During the measurement, the WSS transmitted all measurement data from the MEMS sensors (the transmission control algorithm was disabled). Each volunteer performed six measurement gestures, which are presented in Figure 12a through Figure 12f. For the purposes of the research, a measurement procedure was designed, in which the time of performing individual gestures and the time of the control gesture were determined. The set times ensured repeatability in reproducing the sequence of gestures by individual volunteers. In addition, the performance of successive gestures in accordance with the adopted measurement procedure ensured the diversified hand movement dynamics as well as the diversification of the input data for testing  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Case Number**} & \multicolumn{2}{c}{**Mean (kB/s)**} & \multicolumn{2}{c}{**Difference (\%)**} \\ \cline{2-5}  & **Ethernet** & **Wi-Fi** & **Ethernet** & **Wi-Fi** \\ \hline P1 & 4.50 & 3.80 & \(-91.60\%\) & \(-91.52\%\) \\ P2 & 6.20 & 5.49 & \(-88.43\%\) & \(-87.76\%\) \\ P3 & 8.82 & 9.36 & \(-83.54\%\) & \(-79.11\%\) \\ P4 &  
the transmission algorithm. Each measurement gesture was performed for 3 s. In the measurement procedure, a control gesture was also introduced--the hand was positioned horizontally with the fingers extended (Figure 12g). The control gesture was performed before the beginning of the series of measurement gestures, after its completion and between each of the measurement gestures. The control gesture was also performed for about 2-3 s. With the participation of volunteers, three measurement cycles were carried out, in which three series of gestures were performed (9 series in total). There was a 10-s pause between the series of gestures.  
From the received data, only the values from the 3D gyroscopes were analysed, and the \(d_{i}\) parameter was calculated for each vector \(\omega_{i}\) according to the Formula (2). Then, the local maxima were determined for the data from all the series of measurements. The maxima occurred at the time of performing the measurement gesture, or switching to the control gesture (12 maxima per series). The arithmetic mean was calculated from the set of maxima. The threshold values of _TH1_, _TH2_, and _TH3_ were 1/4, 1/2, and 3/4 of the calculated mean, i.e., 84.21, 168.42, and 252.63, respectively.