## 6 Construction of a Chemical Enterprise Management Platform Based on the Immune Model
### People-Management Platform Based on Location Service  
A personnel-management platform was established based on personnel positioning technology. Considering the actual situation and positioning accuracy of the chemical plant, UWB technology is used to establish personnel positioning system. UWB personnel positioning system is mainly composed of base station with known location, positioning tag, and upper computer (Figure 7). One of the base stations is set as the main base station, and the location data is transmitted to the top computer in real time through serial connection, and the later data processing is carried out through corresponding program software. Location estimation  
The TDOA method is used to calculate the position coordinate to achieve wireless location ranging. As shown in Figure 8, the time difference from the positioning tag to the two nearby positioning base stations is measured first, and then the distance difference can be obtained by multiplying the speed of light. Only two distance differences are required to obtain a set of hyperbolic equations. TDOA method only needs to obtain the time difference, so it does not require the base station synchronize with the tag, which greatly improves the measurement accuracy of the positioning system. Assume that the coordinates of three base stations are \(1\#\left(x_{1},y_{1}\right)\), \(2\#\left(x_{2},y_{2}\right)\), and \(3\#\left(x_{3},y_{3}\right)\), respectively, and tag coordinates are \(\left(x,y\right)\). The time difference of tag to base stations \(1\#\) and \(3\#\) is \(T=T_{3}-T_{1}\), and then the distance difference between base station \(1\#\) and \(3\#\) is \(D=C\times T\). Consequently, a set of hyperbolic \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Evaluation Indicator** &
\begin{tabular}{c} **Grade of the** \\ **Evaluation** \\ \end{tabular} & **Results** \\ \hline \multirow{8}{*}{**Index layer**} & Personnel on-job management B11 & 6.37 & good \\  & Behavior safety observation B12 & 3.14 & **poor** \\  & Personnel safety training B13 & 5.87 & ordinary \\  & Risk control of hazardous operations B14 & 5.47 & ordinary \\  & Monitoring and early warning of major & & \\  & hazard sources B21 & 5.14 & **ordinary** \\  & Monitoring and warning of high-risk & & \\  & processes B22 & 5.28 & ordinary \\  & Video surveillance of vital parts B23 & 8.03 & very good \\  & Inherent facility risk management B24 & 7.06 & good \\  & Risk monitoring map B31 & 7.51 & good \\  & Monitoring and warning of toxics B32 & 4.84 & **ordinary** \\  & Occupational disease risk monitoring B33 & 8.36 & very good \\  & Risk prevention and control objective & 6.23 & good \\  & management B41 & 7.31 & good \\  & Risk identification and control B42 & 5.73 & general \\  & Risk investigation and management B43 & 5.73 & general \\  & Emergency management B44 & 5.97 & general \\  & Training learning assessment B45 & 6.43 & good \\ \hline \multirow{4}{*}{**Element factor**} & Unsafe behavior of people /B1 & 5.27 & general \\  & Unsafe state of things /B2 & 6.25 & good \\ \cline{1-1}  & Poor operating environment /B3 & 6.59 & good \\ \cline{1-1}  & Safety Management /B4 & 6.34 & good \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Evaluation results of evaluation indexes at each layer. The tag will exchange information with three base stations at the same time. Finally, the packet containing the label address, base station addresses, and signal propagation times will be sent to the upper computer, and the actual location coordinates of the tag will be calculated according to the information. Based on the base station location and signal flight time, the tag position can be solved by establishing a mathematical model. The Chan positioning algorithm is a most widely used positioning solution method based on TDOA, which can calculate high-precision position coordinates with a small amount of calculation. If the coordinates of three stations are \((x_{k},\,y_{k})\), then the distance between tag and base station is \(R_{k}\), \(k=1,2,3\).