# Knowledge-Graph-Based Integrated Line Loss Evaluation Management System
## 2 Constructing a Knowledge Graph for Comprehensive Line Loss Evaluation Management
### Portfolio Evaluation Analysis Based on DEMATEL-Entropy Weight-TOPSIS  
The DEMATEL method is a methodology proposed for screening the main elements of complex systems and simplifying the process of analyzing their structure. This method makes full use of the experience and knowledge of experts to deal with complex problems and is especially effective for those systems with uncertain element relationships. However, DEMATEL evaluation tends to be more subjective by experts and is easily influenced by personal thoughts, so the Entropy-Weight objective assignment method is proposed. The Entropy-Weight method can objectively reflect the differences between different indicators and the degree of importance, and the calculation results are more accurate, but it needs the indicators to conform to a normal distribution as much as possible, and it is not good for dealing with individual extreme values. At the same time, the indicators are not completely independent from each other, and the correlation between the indicators cannot be taken into account. Therefore, this paper will analyze the connotation of low carbon competitiveness based on the comprehensive use of a variety of evaluation ideas, the combination of subjective and objective evaluation methods, and the combination of multiple evaluation methods so that the subjective and objective evaluation methods can complement each other; the competitiveness of the regional line loss is a comprehensive, scientific, and objective evaluation, to ensure that the indicator weights not only truly reflect the objectivity of the data but also ensure that the indicator system has a predictive nature.  
The TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) method is a sort of ordering method close to an ideal solution; it is based on a limited number of evaluation objects and the degree of proximity to the idealized target for the order is a commonly used and effective evaluation method in multi-objective decision-making analysis [28]. It is because the method can be more objective to the evaluation object to carry out scientific and reasonable sorting, so it is widely used by scholars to evaluate the sample data, but the defect of applying the general TOPSIS method is that it does not take into account the weights of the indicators, and it adopts a one-dimensional qualitative approachto average the weights of the evaluation indicators to sort the evaluation object, which will lead to a certain research bias between the evaluation results and the objective actual values. This paper will be based on the above subjective and objective combination of calculated weight results, using the weighted TOPSIS method to construct a DEMATEL-Entropy Weight-TOPSIS evaluation method based on the Nanning City line loss competitiveness of the calendar year score calculation; the specific calculation process is as follows.  
Same as the trending and indicator dimensionless, for both positive and negative indicators, the normalization formula is  
\[a_{ij}= (x_{ij}-\min x_{ij})\ /\ (\max x_{ij}-\min x_{ij}) \tag{12}\]  
Calculation of the distances \(D_{i}^{+}\) and \(D_{i}^{-}\) from the best and worst options for each evaluation object.  
\[D_{i}^{+}=\sqrt{\sum_{j=1}^{m}w_{j}\ (a_{ij}-a_{ij}^{+})^{2}} \tag{13}\]  
\[D_{i}^{-}=\sqrt{\sum_{j=1}^{m}w_{j}\ (a_{ij}-a_{ij}^{-})^{2}} \tag{14}\]  
Calculate the proximity of each evaluation object to the optimal and worst options:\(C_{i}\):  
\[C_{i}=\frac{D_{i}^{-}}{D_{i}^{+}+D_{i}^{-}} \tag{15}\]