## 2 Derivation and Analysis for Statistical Indoor EZ
\begin{table}
\begin{tabular}{c c} \hline \hline
**Regions According to Angle** & **Observation Angle Range** \\ \hline _Region 1_ & \(0^{\circ}<\phi_{T}<30^{\circ}\) \\ _Region 2_ & \(30^{\circ}<\phi_{T}<60^{\circ}\) \\ _Region 3_ & \(60^{\circ}<\phi_{T}<90^{\circ}\) \\ _Region 4_ & \(90^{\circ}<\phi_{T}<120^{\circ}\) \\ _Region 5_ & \(120^{\circ}<\phi_{T}<150^{\circ}\) \\ _Region 6_ & \(150^{\circ}<\phi_{T}<180^{\circ}\) \\ _Region 7_ & \(180^{\circ}<\phi_{T}<210^{\circ}\) \\ _Region 8_ & \(210^{\circ}<\phi_{T}<240^{\circ}\) \\ _Region 9_ & \(240^{\circ}<\phi_{T}<270^{\circ}\) \\ _Region 10_ & \(270^{\circ}<\phi_{T}<300^{\circ}\) \\ _Region 11_ & \(300^{\circ}<\phi_{T}<330^{\circ}\) \\ _Region 12_ & \(330^{\circ}<\phi_{T}<360^{\circ}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Detailed information of all observation regions. Figure 1: Process to obtain the statistical EZs based on electromagnetic field strengths in the indoor environment: (**a**) indoor regions; (**b**) acquisition of the statistical EZ boundary for _Region n_. Figure 2 shows the photograph and geometry of the indoor environment of the simulator room of the KINS. The KINS simulator room is similar to the actual control room of the NPP, so it is suitable for examining the indoor electromagnetic fields of the NPP. To investigate the statistical indoor EZ, the indoor environment of the simulator room of KINS is modeled using Wireless InSite electromagnetic simulation software [9]. The entire simulator room has dimensions of 15 m \(\times\) 18 m \(\times\) 6 m. There are some interior structures (monitoring devices, control equipment, cabinets, and tables) in which the internal structures are typically made of metal or wood materials. In Figure 2b, the monitoring devices and control equipment are marked as \(A\) and \(C\), while the metallic cabinet and the table are represented by \(B\) and \(E\), respectively. \(D\) and \(G\) are wooden cabinets, and \(F\) is a wooden table. The coordinates of the transmitting antenna are denoted by \(x_{t}\) and \(y_{t}\). The dimensions of all interior structures can also be represented by \(w\) m \(\times\)\(l\) m \(\times\)\(h\) m, where \(w\) and \(l\) are the width and length from the top view, \(h\) is the height, and \(t\) is the thickness of each interior structure. The detailed parameters of all modeled structures are listed in Table 2.  
Figure 3 illustrates the received power distributions according to the transmitting antenna position using Wireless InSite electromagnetic simulation software [9]. The total radiated power and frequency of the transmitting signal are assumed to be 1 W and 2.4 GHz, respectively. Herein, 2.4 GHz is used for observation, since the frequency band is used in various applications such as Bluetooth, Wi-Fi, and WirelessHART [15; 16; 17]. In order to make the simulation results more consistent with the actual values, the measured \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Symbols** & \(w\)**(m)** & \(I\)**(m)** & \(t\)**(m)** & \(h\)**(m)** \\ \hline \(A\) & 11.2 & 3.3 & 1.2 & 3 \\ \(B\) & 3 & 0.6 & - & 2 \\ \(C\) & 1.8 & 7.2 & - & 2 \\ \(D\) & 3 & 3 & 0.5 & 1.2 \\ \(E\) & 3.8 & 3.8 & 1.2 & 0.8 \\ \(E_{I}\) & 10.2 & 3.2 & 1.2 & 0.8 \\ \(F\) & 4.2 & 1.2 & - & 0.8 \\ \(G\) & 0.3 & 6.6 & - & 2 \\ \(H\) & 0.9 & 1 & 0.6 & 1.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Parameters of the structure in Figure 2b. Figure 2: Photograph and geometry of the simulator room in KINS: (**a**) photograph; (**b**) geometry. radiation pattern of the dipole antenna (for transmitting and receiving antennas) is used as the input for the simulation. Detailed information of the fabricated dipole antenna will be introduced in Section 3. The position of \(Tx\). 1 is assumed at \(x_{t}\) = 9.5 m and \(y_{t}\) = 6.5 m. The height of the transmitting antenna is 1.4 m, which is higher than most interior structures in the simulator room.