0. Introduction
In the context of the implementation of "dual carbon", the reform of the power system is deepening, all sectors of society pay more and more attention to the application of renewable energy, and the demand of power users for clean energy is also growing. Only by further increasing the proportion of renewable energy and making it deeply replace traditional fossil fuels, can the high carbon coal, natural gas and other power systems develop in a low-carbon or even zero carbon direction [
1], and achieve a Low-carbon economy. A large number of power selling companies have emerged, and the demand for high-quality electricity from social power users is also constantly increasing [
2]. High quality electricity refers to electricity with higher power quality indicators than those specified in existing public grid power supply regulations and restrictive standards [
3]. For electricity sales companies, they need to attract electricity users by setting reasonable electricity sales package prices, improving power quality, increasing the proportion of renewable energy, and providing additional value-added services. For power users, they need to choose appropriate electricity sales packages based on different needs such as power supply reliability and electricity cost [
4]. Therefore, the matching between electricity users and electricity sales package can not only improve the revenue of electricity sales companies, meet the demand of users for high-quality electricity, but also has great significance in promoting the operation of the Low-carbon economy.
At present, the main method for power users to choose the electricity sales package is that the electricity sales company recommends the electricity sales package, and then the power users make the decision. For power selling companies, recommending appropriate power selling package services for users is an effective way to improve the viscosity of power users to power selling companies and attract a large number of new users for power selling companies [
13]. At present, there are two main methods for recommending electricity sales packages: indirect recommendation and direct recommendation. There are two main categories of existing indirect recommendation methods, namely statistical analysis recommendation method and mathematical modeling recommendation method. In statistical analysis, the main methods used include regression analysis, cluster analysis, and preference analysis. Reference [
5] studied the impact of income, consumption expenditure and price on household electricity consumption based on Quantile regression analysis, avoiding sampling deviation, and providing more accurate electricity sales package for families; Reference [
6] uses time load time series to cluster and analyze residential electricity customers, extracting customer behavior or load curves from the time series, in order to more targeted recommend electricity sales packages to users; Reference [
7] used a preference analysis based approach to develop fair energy allocation policies and unified pricing mechanisms for energy trading in P2P markets. However, in statistical analysis methods, most rely more on reliable and sufficient data. If the data quality is low or the data volume is small, it may reduce the accuracy of recommendation results. In mathematical modeling, the main methods used are Collaborative filtering method and mixed recommendation method. Among mathematical modeling methods, Collaborative filtering method and hybrid recommendation method are two commonly used methods. Reference [
8,
9] measures the relationship between users or products through collaborative filtering, looks for similar neighbor sets, and then completes the recommendation. However, the attribute of the item itself is not considered in the recommendation, which is easy to reduce the accuracy of the recommendation; Reference [
10] based on the collaborative recommendation algorithm, designed a recommendation method of electricity sales package in Spark environment, comprehensively considered the power users and electricity sales package volume to predict and score, and obtained the recommendation data; Reference [
11] designs a recommendation system for electricity sales package based on collaborative filtering and hybrid Bayesian algorithm according to the electricity consumption characteristics of power users; Reference [
12] is based on the artificial intelligence technology of collaborative filtering, and recommends the electricity sales package according to the energy consumption characteristics of intelligent building customers. Although the indirect recommendation method is widely used, because the collaborative filtering method needs to cluster users, it needs to set the number of clusters in advance, which leads to low accuracy and efficiency of clustering, and reduces the accuracy of the method. And since the model is based on historical data, the recommendation performance of the model may be limited when there is a lack of historical data or the data is too old. In the direct recommendation method, it is mainly through the use of iSelect [
13], Check24 [
14] and other power selling package recommendation platforms. However, this method is mainly based on the power selling price and lacks many key factors that have an important impact on the electricity price, so the recommendation results are not accurate. In addition, among the two major categories of recommendation methods mentioned above, when the power user and the electricity sales package evaluate each other, they do not take into account the situation that the power user may not know about the additional services of the electricity sales package and the electricity sales company may not know about the preferences of the power user. However, in the actual situation, due to various factors such as the source of information and the large number of electricity sales packages, it is often difficult for the power user to thoroughly understand the specific information of various electricity sales packages, Therefore, how power users make the best choice under limited cognition is an urgent problem to be studied.
To sum up, this paper proposes a decision-making method of user's electricity sales package considering incomplete fuzzy preference relationship. This method can take the subjective psychological feelings into account, and overcome the limitations of limited knowledge or understanding between the matching parties, and still accurately determine the optimal matching scheme under certain conditions of missing information. The process of this method is: First of all, the priority vector of power users and electricity sales package is determined based on incomplete fuzzy preference relationship; Then, a method to describe the satisfaction of electricity users and electricity sales packages based on the disappointment theory is proposed; Then, a multi-objective optimization model based on the two-sided matching method is proposed, which aims at maximizing the overall satisfaction of the matching between power users and electricity sales packages; Finally, a case study of power users in an industrial park in Zhejiang Province is carried out to verify the feasibility and effectiveness of the matching decision-making method of user's electricity sales package considering incomplete fuzzy preference.
The characteristic of disappointment theory is its asymmetric sensitivity, dual threshold effect, abstention effect, and intuitive effect. Asymmetric sensitivity refers to the fact that both matching parties are more sensitive to disappointment; The dual threshold effect refers to the existence of two thresholds for the sensitivity of both matching parties to risk. When one threshold is reached, the sensitivity to risk increases, and when the other threshold is exceeded, the sensitivity to risk decreases; The abstention effect refers to the fact that both parties in the match will give up the option with higher returns due to fear of disappointment; Intuitive effect refers to the fact that when faced with a large number of risks and decision-making choices, both matching parties often make choices based on intuition.
The characteristics of incomplete fuzzy preference are fuzziness, uncertainty, environmental dependence, relativity, and subjectivity. Ambiguity refers to the imprecise preferences given by both matching parties; Uncertainty refers to the hesitation phenomenon caused by the difficulty of predicting the consequences of each decision by both matching parties in decision-making; Relativity refers to the fact that the decision results given by both matching parties will be influenced by the environment, resulting in discrepancies in the decision results; Subjectivity refers to the fact that every decision is the result of matching the subjective experiences and judgments of both parties.
2. Matching method between power user demand and power selling package of power selling company
2.1. Overview of two-sided matching problem (TSMDM)
The purpose of two-sided matching problem is to find the best matching method between objects on both sides according to the preference information or evaluation results provided by matching objects, so as to maximize the interests of both sides. In this paper, set the power user as a matrix, representing the i-th user in the power user set, . Set the electricity sales package as a collection (). refers to the j-th electricity sales package in the electricity sales package set,. Two-sided matching is a one-to-one mapping from set P to set Q. Wheremeans that the power user matches the electricity sales package, and vice versa. It should be noted that there will be m-n packages that will not be selected.
The existing definitions are as follows: indicates the user's satisfaction with the package, and indicates the adaptation degree of the package to the user. If there are two situations: 1.,makingand.2. ,making , then the two-sided match is unstable, otherwise it is a stable two-sided match.
Next, we introduce a binary variable
to indicate whether
and
is matched. The conditions for stable two-sided matching can be defined as follows:
2.2. Incomplete fuzzy preference relationship
For convenience, the assumption is a set of fixed options of the decision-maker, which represents the fuzzy preference degree of the i-th element in the decision-maker set X. We use a matrix to describe it. indicates that for decision-maker,is better than;indicates that the is not preferred to;and indicates thatandare equally preferred. In order to make the results more rigorous, we stipulate .
In fuzzy preference matrix A, if some elements are unknown, then A is called incomplete fuzzy preference relation matrix. If at least one element other than diagonal is known in each row and column, then A is called an acceptable incomplete fuzzy preference matrix, otherwise it is unacceptable.
2.3. Subjective satisfaction
Generally speaking, a power user has different preferences for different power sales packages, and for a certain power sales package, the power company has different preferences for different power users. Therefore, we can rank the satisfaction of electricity users and electricity sales packages.
We assume that it is used to express the subjective satisfaction matrix of the electricity sales package given by the power users according to their own demand for electricity, and the elementrepresents the subjective satisfaction of the power userwith the electricity sales package,which reflects the’s preference for. The greater the value, the higher the degree of preference. In the same way, represents the subjective satisfaction matrix of power users given by the power sales package according to their preferences for power users, and the elementrepresents the subjective satisfaction of the power sales packageto power user.
We assume that is used to represent the incomplete fuzzy preference relationship of power userfor m kinds of electricity sales packages, whererepresents the result ofcomparing electricity sales packagewith the electricity sales package . means that the preference of power userfor the packageis less than that for the package; means that the preference of power userfor the packageis higher than that for the package;means that the preference of power usersfor the packageis the same as that for the package.In addition, if power users cannot compare the two packages, data will be missing, asindicated by.
In order to obtain the priority weight vector of each power user for all electricity sales packages, we need to introduce an indicator matrix
, where
The priority weight vector of power user
can be obtained by the
LLSM method proposed in reference [
29]. The specific steps are as follows:
First, use the indicator matrix to obtain the matrices
D and
Y
Next, the matrix
D and Y are substituted into the formula to
obtain the
W vector, and then the vector
W is substituted into the formula (16) to obtain the
priority weight vector of power users
.
Ifis an unacceptable incomplete fuzzy preference relation matrix, the priority weight vector can be obtained through the following steps:
1.Remove the rows and columns with only one known element (assuming that the first row, the first column, ()) to obtain a new acceptable incomplete fuzzy preference matrix;
2.Use the above method to obtain an incomplete priority weight vector ;
3.Insert - M in the line next to line l-1 of the vector, or - M in the line above line l+1.- M shows that the decision-makers have no clear preference for the first type of electricity sales package.
Finally, power users
' subjective satisfaction with the electricity sales package
can be expressed by
.
Similarly, we set to represent the incomplete fuzzy preference relationship of the electricity sales packagefor n power users.
In the same way, it can be concluded that the subjective satisfaction degree of the electricity sales package
with the power user
can be expressed by
.
Where is a set containing user’s effective preference information; is a set containing the effective preference information of the package.
2.4. Two-sided matching decision based on disappointment theory
The theory of disappointment was first put forward by Bell in reference [
34]. He believed that disappointment is a psychological reaction of decision makers by comparing actual results with expected results. The two-way choice between power users and electricity sales packages is the product of satisfying two-sided satisfaction at the same time. It is a psychological evaluation of the currently selected objects by both sides, and is related to the psychological perception of disappointment and joy. Disappointment is the sense of dissatisfaction when the actual result does not meet the expected standard of the decision-maker; Joy is the satisfaction generated when the actual result exceeds the expected standard of the decision-maker.
Assume that the priority weight vector value of power userfor the electricity sales package is ranked from low to high:. If and match, at this time, the satisfaction of power useris not only related to the electricity sales package, but also related to other electricity sales packages. On the one hand, because the packages in the collection are inferior to, power userwill feel happy because they do not match them; On the other hand, because the packages in the collection are better than, power userwill be disappointed because they do not match them.
In the same way, the same is true for the electricity sales package.
Therefore, to evaluate the satisfaction of power users and electricity sales packages with the matching results, we need to consider the disappointment - joy perception of both sides, so that we can more accurately describe the satisfaction degree of power users and electricity sales packages.
Because there is a lack of subjective evaluation elements in the subjective satisfaction matrix of power users
and the subjective satisfaction matrix of electricity sales packages
, so we build a collection
Set (19) refers to the set of electricity sales packages that can match each otherin the electricity sales package set Q. Set (20) represents the set of power users that can match each other in the power user set P for the power sales package.
If the power user
matches the
electricity sales package
,
means that the correction of subjective satisfaction degree after adding the disappointment - joy feeling of the power user, according to the definition,
can be expressed as:
In formula (21), represents the user's disappointment value and represents the user's joy value.
For the matching object
, if there is a certain electricity sales package
,leading to
,than the power user
will be disappointed when matching with the electricity sales package
instead of matching
. Set the collection
as a collection of objects that will cause
disappointment after matching with
. At this time, the user
's disappointment value can be calculated using the following formula:
In the same way, it will also exist
, leading to
, so that
will feel happy when matching with
instead of
. Set the collection
as the collection of objects that
will produce a sense of joy after matching with
. At this time, the user
's happiness value can be calculated by the following formula:
In formulas (22) and (23), the
reciprocal of the number of electricity sales packages that disappoint power user
and the reciprocal of the number of electricity sales packages that delight power user
,which are respectively expressed as follows:
In the same way, if the electricity sales package
matches the power user
,
represents the correction of subjective satisfaction after adding electricity sales package
's disappointment-joy feelings,
can be expressed as:
The specific expressions of disappointment function
and joy function
are as follows:
In the formula(31) and (32), andare the disappointment and joy parameters, indicating the degree of influence of the feeling of joy on the evaluation results,,,. The smaller, the greater the sensitivity of power users to the disappointment of the electricity sales package and the less likely they are to choose the electricity sales package; The larger , the greater the sensitivity of power users to the joy of the electricity sales package, and the more likely they are to choose the electricity sales package.
To sum up, the satisfaction evaluation matrix of power users after adding disappointment - joy perception is:
The satisfaction evaluation matrix of the electricity sales package is:
2.5. Multi-objective optimization model
Next, after obtaining the satisfaction matrix of power user set P and the satisfaction matrix of power sales package set Q, a two-objective optimization model will be constructed, and the optimal stable matching of both parties will be obtained by solving the model.
Setas a binary decision variable. When the user matches the package, , otherwise.
With the maximum satisfaction of power users and electricity sales package as the optimization objective, a stable two-sided matching multi-objective optimization model can be established:
In the above model, formula (35) and formula (36) are objective functions, which describe the maximization of satisfaction between power users and electricity sales packages. Equations (37) and (38) are inequality constraints, which respectively ensure that each object in user P can only match one package in package Q at most and one power selling package in package set Q can only match one user in user set P. Equation (39) is a stable two-sided matching constraint, including two situations: 1. Power userand electricity sales packagematch each other; 2. If the power user does not match the electricity sales package, then the power userwill match the electricitysales package with a higher degree of preference or the electricity sales packagewill match the power userwith a higher degree of preference.
In order to facilitate the solution, the weight coefficient
is introduced to transform the two-objective optimization model into a single-objective optimization model:
In the model (41), Z represents the total satisfaction of the matching parties, is a weight coefficient, indicating that the feeling of power users is more important than the adaptation degree of the electricity sales package; indicating that the adaptability of the electricity sales package is more important than the satisfaction of the power users; indicating that both parties are equally important. In this paper, we will takefor analysis.
Based on the two-sided matching theory, and adding the disappointment - joy perception effect of power users and electricity sales packages, the stable two-sided matching process between power users and electricity sales package is shown in
Figure 3:
4. Conclusions
In this paper, a two - sided matching decision-making method based on disappointment theory is proposed. Firstly, this method is based on incomplete fuzzy preference relationships, which expands the applicability of recommendations; Secondly, by incorporating the influence of disappointment theory, the accuracy and efficiency of recommendations are improved; Finally, the goal is to maximize the overall satisfaction between power users and electricity sales packages, which can ensure the optimality and stability of recommendation results. The advantages of the methods proposed are listed as follows. Firstly, the method proposed in the article is based on the incomplete fuzzy preference relationship between power users and electricity sales packages, which can overcome the problem of missing preference data caused by different knowledge and cultural backgrounds of power users; Secondly, the two-sided matching decision-making method proposed in this article also incorporates the influence of disappointment theory, which can not only better measure the satisfaction between power users and electricity sales packages, but also help set decision-making goals and greatly improve decision-making efficiency. In addition, by comparing the preference information of two matching objects one by one, this method greatly reduces the burden in the process of extracting preference information, can extract preference information faster and more flexibly, and ensures good recommendation results. At the same time, this method will also promote the development of Low-carbon economy under the background of "double carbon" landing.
However, the bilateral matching decision-making method proposed in this article also has certain limitations:1.The method only considers the one-to-one problem but didn’t consider the one-to-many matching problems.2.The method only considers the accurate evaluation of electricity sales packages by power users, without further discussing the fuzzy preference relationships or hesitant preference information that may exist in real life.
Therefore, in future research, the focus of research will be to address the above two shortcomings: the consensus issues and complex preference structure issues of power users will be deeply considered, and further in-depth research will be conducted on the matching problem between power users and electricity sales packages to more accurately and efficiently recommend electricity sales packages.