## 2 Methodology  
### Classification of Customer Groups  
#### 2.1.1 Building Sample Customer Portrait Label System  
First, to help readers better understand the DH-MAGDM proposed in this paper, a complete diagram covering all the applied methodological procedures is shown in Figure 1.  
The energy usage and consumption habits of different types of customers vary, as reflected in their differing preferences and selection outcomes for electricity sales packages. To better distinguish the practical differences in electricity demands and systematically describe customers' electricity usage characteristics from multiple perspectives, this study employs a sample customer set \(R~{}=~{}\{R_{1},R_{2},\ldots,R_{i},\ldots,R_{I}\}\). The load dataset for sample customers on a given day of a specific month is represented as \(P~{}=~{}\{P_{R_{1}},P_{R_{2}},\ldots,P_{R_{i}},\ldots,P_{R_{I}}\}\), where the load data for customer \(R_{i}\) is \(P_{R_{i}}~{}=~{}\{P_{R_{i},1},P_{R_{i},2},\ldots,P_{R_{i},m},\ldots,P_{R_{i}, M}\}\). Here, \(M\) represents the total number of hours in a month, and \(I\) represents the total number of customers in the sample set. This study employs 6 key metrics to characterize sample customers, which are defined as follows:  
Figure 1: Flowchart of dynamic hybrid multi-attribute group decision-making with two reference points for electricity sales package recommendation. 1. Monthly Load Rate: The Monthly Load Rate \(b_{R_{i}}^{1}\) is used to reflect the fluctuation of electricity load within a month. It is calculated as the ratio of the average monthly load (\(P_{R_{i}(av)}\)) to the maximum load (\(P_{R_{i}(\max)}\)), as expressed in the following formula: \[b_{R_{i}}^{1}\ =\ \frac{P_{R_{i}(av)}}{P_{R_{i}(max)}}\ =\ \frac{\sum\limits_{m = 1}^{M}P_{R_{i},m}/\,M}{P_{R_{i}(max)}}.\] (1)  
A larger value of \(b_{R_{i}}^{1}\) indicates that customer \(R_{i}\) has a higher ratio of average power load to maximum power load within the month, signifying greater fluctuations in their power load. 2. Peak-Time Load Rate: The Peak-Time Load Rate \(b_{R_{i}}^{2}\) is defined as the ratio of the electricity consumption during peak hours to the total electricity consumption for customer \(R_{i}\). The peak load during the time period 8:00-16:00 in a given month is represented by \(P_{R_{i},h,m}\). The formula is expressed as follows: \[b_{R_{i}}^{2}\ =\ \frac{\sum\limits_{m = 1}^{M}P_{R_{i},h,m}}{\sum\limits_{m = 1}^{M}P_{R_{i},m}}.\] (2)  
A larger \(b_{R_{i}}^{2}\) value indicates a higher utilization rate of electricity during peak hours throughout the month. This also indirectly suggests smaller fluctuations in the monthly electricity load, as the customer's consumption is more concentrated during peak periods. 3. Off-Peak Load Rate: The Off-Peak Load Rate \(b_{R_{i}}^{3}\) represents the ratio of electricity consumed during off-peak hours to the total electricity consumption for customer \(R_{i}\). The off-peak load during the time period 22:00-5:00 (the following day) in a given month is denoted as \(P_{R_{i},l,m}\). The formula is expressed as follows: \[b_{R_{i}}^{3}\ =\ \frac{\sum\limits_{m = 1}^{M}P_{R_{i},l,m}}{\sum\limits_{m = 1}^{M}P_{R_{i},m}}.\] (3)  
A larger \(b_{R_{i}}^{3}\) value indicates a higher utilization rate of electricity during off-peak hours throughout the month. This also indirectly suggests smaller fluctuations in the monthly electricity load, as the customer's consumption is more concentrated during off-peak periods. 4. Flat-Time Load Rate: The Flat-Time Load Rate \(b_{R_{i}}^{4}\) represents the ratio of electricity consumed during flat (non-peak and non-off-peak) hours to the total electricity consumption for customer \(R_{i}\). The flat-time load for a specific day in a month, excluding peak and off-peak hours, is denoted as \(P_{R_{i},k,m}\).