## 4 Model Development
### Matter-Element Extension Method  
Establishing the Matter Element Model to Be Evaluated  
The matter-element method is an ordered triple composed of the evaluation object U, the feature T, and the value V about T [45]. R = (U, T, V) is the basic element of the description, referred to as the matter element. It is assumed that the suitability evaluation grade U has n characteristics, with \(T_{1}\), \(T_{2}\),..., \(T_{n}\) and specific values \(V_{1}\), \(V_{2}\),..., \(V_{n}\) to describe them; the suitability evaluation model can be expressed as follows.  
\[R=(U,\ T,\ V)=\left[\begin{array}{c}U\ T_{1}\ V_{1}\\ T_{2}\ V_{2}\\ \vdots\vdots\\ T_{n}\ V_{n}\end{array}\right] \tag{1}\]  
where \(R\) is the evaluation matter element; \(U\) is divided into \(K\) suitability grades; \(T_{n}\) is the adaptability evaluation index; \(V_{n}\) is the value range of evaluation grade about each evaluation index; and \(V\) = [a, b].  
Establishing the Classical Domain \(R_{j}\) Thing Element Model  
\[R_{j}\)= \((U_{j},T_{i},\ V_{ji})=\left[\begin{array}{c}U_{j}\ T_{1}\ \left<a_{j1},\ b_{j1}\right>\\ T_{2}\ \left<a_{j2},\ b_{j2}\right>\\ \vdots\ \vdots\\ T_{n}\ \left<a_{jn},\ b_{jn}\right>\end{array}\right] \tag{2}\]  
where \(R_{j}\) is the classical domain matter element [46]; \(U_{j}\) is the Kth evaluation grade, \(j\) = 1, 2, 3,..., \(n\); \(T_{i}\) is the i th evaluation index, i = 1, 2, 3,..., \(n\); \(V_{ji}\) is the value range of the jth evaluation grade about the ith evaluation index; \(b_{ji}\) is the upper limit of the value; \(a_{ji}\) is the lower limit of the value; and \(V\) = [\(a_{ji}\), \(b_{ji}\)].  
Establishing a Section Domain R\({}_{\rm x}\) Matter Element Model  
\[R_{x}\)= \((U_{x},\ T_{i},\ V_{xi})=\left[\begin{array}{c}U_{X}\ T_{1}\ \left<a_{x1},b_{x1}\right>\\ T_{2}\ \left<a_{x2},b_{x2}\right>\\ \vdots\ \vdots\\ T_{n}\ \left<a_{xn},b_{xn}\right>\end{array}\right] \tag{3}\]  
Among them, \(R_{x}\) is a section domain matter element [46]; \(U_{X}\) is the overall rating; \(V_{xi}\) is the value range of all evaluation grades about the \(i\)th evaluation index; \(a_{xn}\) is the lower limit of the value in all the evaluation grades; \(b_{xn}\) is the upper limit of the value of the value in all the evaluation grades; and \(V_{xi}\) = [\(a_{xn},b_{xn}\)].  
Determining the Matter Element \(R_{o}\) to Be Evaluated  
\[R_{o}\)= \((U_{0},\ T_{i},\ V_{i})=\begin{bmatrix}U_{0}&T_{1}&V_{1}\\ T_{2}&V_{2}\\ \vdots&\vdots\\ T_{n}&V_{n}\end{bmatrix} \tag{4}\]  
Among them, \(U_{0}\) is the object to be treated; \(V_{i}\) is the value of \(U_{0}\) with respect to \(T_{i}\), which is the specific value of the object to be evaluated.  
Calculating the Correlation Degree and Evaluation Grade  
Step 1: Calculate the distance from the \(U_{0}\) index value \(V_{i}\) to the classical domain interval \(V_{ji}\) and the section domain interval \(V_{xi}\)[46]:  
\[\text{P }(V_{i},\ V_{ji})=\left|V_{i}-\frac{1}{2}(a_{ji}+b_{ji})\right|-\frac{1} {2}(b_{ji}-a_{ji}) \tag{5}\]  
\[\text{P }(V_{i},\ V_{xi})=\left|V_{i}-\frac{1}{2}(a_{xi}+b_{xi})\right|-\frac{1} {2}(b_{xi}-a_{xi}) \tag{6}\]  
where \(p\) (\(V_{i}\), \(V_{ji}\)) is the distance from the index value \(