## 6 Implementation: Case Study
These are summarized in Table 7 and shown in Figure 6. The position of MN is also shown in Figure 6 as a red color, the SNs are represented as a blue color, while RNs are shown as an indigo color. Figure 5: A brief description of an early warning IoT-based system in mines. (1) The initial startup of the entire system takes 90 s at a refresh rate of 1.5 kHz. Installation of the entire setup was completed on 26 July 2016. Prior to extensive monitoring, it was necessary to train the system by having it memorize 300 initial readings. After training, the setup was started at 12:00 a.m., 28 July, so that both off-shift and on-shift gases concentrations can be observed. The performance \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Reader No.** & **Reader Type** & **Location** & **Distance from Incline Lower End (m)** \\ \hline
1 & GN & & \(-23\) \\
2 & RN\({}_{1}\) & Incline & \(-10\) \\
3 & SN\({}_{1}\) & & \(0\) \\ \hline
4 & SN\({}_{2}\) & & \(17\) \\
5 & RN\({}_{2}\) & & \(34\) \\
6 & SN\({}_{3}\) & & \(51\) \\
7 & SN\({}_{4}\) & Main roadway of mine & \(68\) \\
8 & RN\({}_{3}\) & (25 below surface) & \(85\) \\
9 & SN\({}_{5}\) & & \(102\) \\
10 & SN\({}_{6}\) & & \(119\) \\
11 & RN\({}_{4}\) & & \(140\) \\ \hline
12 & SN\({}_{7}\) & & \(46\) \\
13 & SN\({}_{8}\) & Gallery 1 & \(60\) \\ \hline
14 & SN\({}_{9}\) & & \(96\) \\
15 & SN\({}_{10}\) & & \(110\) \\ \hline
16 & SN\({}_{11}\) & & \(151\) \\
17 & SN\({}_{12}\) & & \(160\) \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Stationary nodes SN and router nodes (RN) locations inside the mine (inclined lower end was considered as a reference point). Figure 6: Layout of SNs, RNs, gateway and moving anchor (MN) in the Hassan Kishore coal mine for enhanced safety. evaluation of the sensors in the actual conditions in the mine environment were carried out for the first 24 h with their well-known commercial equivalent instruments including: HOBO U12-012 (12-bit resolution measurement) for temperature and humidity, Gas central CH4C 100 for methane (CH\({}_{4}\)) gas, Telaire 7000 series for CO\({}_{2}\), and Fluke CO-220 for CO. The reading interval was set to 1 min for both the commercial equivalent and our system (OS). Areas with more workers are important areas within the mine. Therefore, only two locations in the mine (mine face 1 and midway mine) have been considered for comparison purposes. We used 300 initial readings to train the normal outputs of monitoring systems, and covariance was computed for the next 400 readings to determine if the incoming measurement is an outlier or not. (2) To check the efficacy of the localization algorithm, two experiments were performed for the RSS calculation by (i) moving the connected MN and (ii) determining the localization error. The localization error was determined by performing an experiment to determine the value of \(g\) (Equation (13)). In these experiments, the degree of contribution of each anchor node was constant at 1. To determine the localization error, experimental settings include: static SNs of known location inside the mine and a MN connected to SNs via a Bluetooth connection. The moving accuracy of the MN carried out by personnel was given attention because it requires uniform motion. Therefore, we ensured that the MNs moved at a uniform speed. The miners were moved up to 30 m from the static node with uniform speed and stopped at 2 m intervals. The RSS values were observed at the SN, which were further processed for determining weighted centroids. One of the features of this approach is that it considers the previously collected RSS values when applying weighted centroids. (3) A network of five connected SNs was created in the proposed topology. SN\({}_{5}\) is the SN connected to GN from the back side, while SN\({}_{1}\) is the last SN in this experimental network. To check for node failure, nodes SN\({}_{2}\) and SN\({}_{4}\) were powered off.