## 2 Experimental Setup and Methods
### Experimental Setup  
The subjects disposed of electronic equipment and metal accessories before EEG measurement. The subjects wore an EEG cap, and the EEG was measured only when the electrode-skin impedance showed a value of 100 k\(\Omega\) or more, which was assumed as a stable condition. After EEG measurement, EEGs were analyzed using the TeleScan program and visualized through three-dimensional brain mapping. In this study, the summer indoor rest condition was set based on the resting state during work, and the experiment was performed under clothing conditions, with short sleeves, long pants, underwater, and socks. To measure the subjects' EEGs during resting indoors, the EEG device (QEEG-64 FX, Lavtha, Korea) was directly connected with the subject's head. This is a high-precision multi-channel wide band biometric system with a three channels bipolar, and it can measure the biosignal by applying HPF, LPF, and Notch filters according to the target signal. The EEG measuring equipment used A2 as the reference electrode, and 16 channels were installed on the subject's head, as shown in Figure 1. In general, both the left and right reference electrodes can be used, but, in some cases, the ECG signal can be mixed with some EEG signals when it is used at the left side. Therefore, the right earlobe (A2) was attached as the reference electrode in this study. The head was primarily divided into four parts to analyze the variation of EEG at different parts of the head, as shown in Table 1. In Figure 1, the frontal lobe zone is composed of prefrontal (Fp1, Fp2), left frontal (F3, F7), and right frontal lobes (F4, F8); the central lobe zone has the parietal (C3, C4, F3, P4), left parietal (P7), and right parietal lobes (P8). In addition, the temporal lobe zone has the left (T7) and right temporal lobes (T8), and the occipital lobe zone has the occipital lobes (O1 and O2). The uBio Macpa device, with a measurement range of 40-200 beats per minute (BPM) and a measurement error of \(\pm\)2%, was also used to measure cardiac activity status. The EEG data was collected using the TeleScan program which was provided by LAXTHA. This program controlled the computerized equipment from the computer side with equipment control, real-time data collection, and time series analysis software, and measured/stored/analyzed in real time. In addition, BrainMap-Addon EEG analysis and 3D brain mapping program were used to analysis of EEG frequency. By these programs, brain mapping visualization, power, and correlation analysis of EEG analysis results were performed. Cardiac activity status was measured by photoelectric pulse wave method. This method is to measure the change of light that passes through the body by irradiating infrared rays and red light on the surface of the human body in order to measure the change in blood flow that changes according to the pulsation of the heart  
In this study, three different seats were employed under indoor rest conditions in summer: a basic seat, which is a general office chair, a ventilation seat, in which indoor air circulates, and a cold water-cooling seat, in which 4 \({}^{\circ}\)C cold water flows using a constant temperature bath. Figure 2 shows a photograph of seat temperatures using a thermal imaging camera when the ventilation and cold water-cooling seats are applied under an indoor temperature of 27.5 \({}^{\circ}\)C in summer. The measuring range of the thermal imaging camera used in this study is \(-\)20-120 \({}^{\circ}\)C, and its thermal sensitivity is \(<\)40 mK @f/1.0, 30 Hz, and 300 K. Applying the cold water-cooling seat for 5 min, the temperature of the seat decreased by 5.7 \({}^{\circ}\)C. In general, ventilation seats are widely used in automobiles. In the ventilation seat, air inflows at the bottom by the fan motor and is discharged through 50 wind-holes, directly flowing to the subject's body. This can increase the drying of sweat and rotation of air. Therefore, it improves the control of the body temperature and improves thermal comfort.