Method for analyzing low-carbon development of inland port

Abstract

The invention discloses an inland port low-carbon development analysis method, and relates to the technical field of inland port low-carbon development. According to the method, an evolutionary game model participated by a government, a port and a shipping enterprise is constructed, and a numerical simulation technology is combined, so that accurate analysis of strategy dynamic evolution of all parties in the low-carbon development process of the port is realized. The method comprises the steps of model parameter initialization, three-party payment matrix construction, replication dynamic equation solving, evolution stability analysis, external variable influence simulation and the like. Key variables such as environmental protection tax, subsidy proportion and emission reduction cost are introduced, and the income balance relationship of three subjects under different strategy combinations is quantitatively analyzed, so that the evolution of the system to the ideal state of positive supervision-low carbon emission reduction-low carbon emission reduction can be dynamically predicted. According to the invention, a quantitative decision-making tool is provided for the government to formulate differentiated supervision policies and optimization and emission reduction strategies of ports and shipping enterprises, and the scientificity and accuracy of low-carbon development of inland ports can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-carbon development of inland ports, and particularly relates to a low-carbon development analysis method for inland ports. BACKGROUND

[0002] As a key node of cargo transportation and an important link in the modern logistics supply chain, ports undertake 90% of the global trade cargo transportation tasks and are the lifeline of global economic and trade development. However, with the rapid development of ocean transportation and inland shipping, the carbon emissions generated by ports and shipping activities each year have exceeded 2-3% of the global emissions, and if effective measures are not taken in time, the emissions will continue to increase.

[0003] In the prior art, some scholars use classical game theory to analyze the low-carbon development of ports, such as constructing a Stackelberg game theory model to optimize the government subsidy port shore power scheme, and constructing a game model based on a duopoly monopoly to study the relationship between port emissions and government regulation. However, the classical game theory is based on the assumption of complete rationality, and can only analyze individual static decision-making behavior, and cannot adapt to the actual scene of long-term dynamic decision-making of multiple interest subjects in the low-carbon development of inland ports. Some other scholars apply evolutionary game theory to this field, such as constructing a green strategy evaluation model for sea shipping liner transportation, and analyzing the influence of port shore power implementation on the evolutionary stable strategies of related interest subjects. However, the existing evolutionary game researches mostly focus on two subjects, or do not systematically consider the comprehensive influence of initial strategy proportion and external variables (environmental tax, subsidy, emission reduction cost) on the evolutionary stable strategies of three subjects (government, port, and shipping enterprise), and it is difficult to comprehensively and accurately provide theoretical support for the government to develop port low-carbon regulation policies, and cannot effectively guide the practice of low-carbon development of inland ports.

[0004] Therefore, the present application constructs an analysis method that can integrate the dynamic game relationship of the government, the port, and the shipping enterprise, and realizes accurate simulation of the low-carbon development path and quantitative evaluation of the policy effect. SUMMARY

[0005] The present application aims to overcome the above-mentioned deficiencies in the prior art, and provides an evolutionary game analysis method for low-carbon development of inland ports. The method is based on the assumption of bounded rationality, constructs an evolutionary game model of three subjects (government, port, and shipping enterprise), systematically analyzes the interest balance problem of the three parties in the process of low-carbon port development, clearly defines the driving factors of low-carbon emission reduction of the port and the shipping enterprise, explores the influence of initial strategy proportion and external variables on the evolutionary stability of the system, provides a theoretical basis for the government to develop scientific and reasonable port low-carbon regulation policies, and promotes the low-carbon development of inland ports.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] An inland port low-carbon development analysis method, comprising the following steps:

[0008] S1. An evolutionary game model involving the participation of government, port and shipping enterprise is constructed, and the strategy set, cost and benefit variables and model assumptions of the three parties are clarified; wherein the strategy set of the government is {active supervision, passive supervision}, the strategy set of the port is {low-carbon emission reduction, traditional development}, and the strategy set of the shipping enterprise is {low-carbon emission reduction, traditional development};

[0009] The cost and benefit variables at least include: the low-carbon emission reduction cost of the port alone The low-carbon emission reduction cost of the port and the shipping enterprise The low-carbon emission reduction cost of the shipping enterprise alone The low-carbon emission reduction cost of the shipping enterprise and the port The active supervision cost C of the government G The social reputation benefit R of the government under active supervision, and the social reputation loss of the government under passive supervision in different scenarios And The government subsidy ratio α, and the environmental protection tax T levied by the government on the port p The environmental protection tax T levied by the government on the shipping enterprise s The low-carbon facility and equipment service fee SC paid by the shipping enterprise to the port, the environmental impact cost ED of both traditional development, and the social benefit WS of both low-carbon emission reduction; the model assumptions at least include that the three parties are all bounded rationality, and need to adjust the decision through multiple game learning; and

[0010] S2. Based on the strategy set and variables determined in step S1, a payment matrix of the three parties is constructed, which covers the payment values of the government, the port and the shipping enterprise under 8 decision combinations, and the 8 decision combinations are {active supervision, low-carbon emission reduction, low-carbon emission reduction}, {active supervision, low-carbon emission reduction, traditional development}, {active supervision, traditional development, low-carbon emission reduction}, {active supervision, traditional development, traditional development}, {passive supervision, low-carbon emission reduction, low-carbon emission reduction}, {passive supervision, low-carbon emission reduction, traditional development}, {passive supervision, traditional development, low-carbon emission reduction}, {passive supervision, traditional development, traditional development};

[0011] S3. Based on the payment matrix of step S2, the expected benefit and average benefit of the government choosing “active supervision” and “passive supervision” are calculated, the expected benefit and average benefit of the port choosing “low-carbon emission reduction” and “traditional development” are calculated, the expected benefit and average benefit of the shipping enterprise choosing “low-carbon emission reduction” and “traditional development” are calculated, and the replication dynamic equation of the three parties is derived according to the evolutionary game theory;

[0012] S4. Evolution trend analysis is conducted on the replicated dynamic equation obtained in step S3, the conditions for the stable strategy of the three parties are solved, and the evolution stable strategies of the government, the port and the shipping company under different conditions are determined;

[0013] S5. The pure strategy equilibrium points of the evolution game equation set of the three parties are solved, the Jacobian matrix is constructed and the eigenvalues of each equilibrium point are calculated to determine the evolution stability of each equilibrium point, and the initial stage, the development stage and the mature stage of the system evolution are divided, wherein the evolution stable strategy of the initial stage is {negative supervision, traditional development, traditional development}, the evolution stable strategy of the development stage is {active supervision / negative supervision, low-carbon emission reduction, traditional development} and {active supervision / negative supervision, traditional development, low-carbon emission reduction}, and the evolution stable strategy of the mature stage is {active supervision, low-carbon emission reduction, low-carbon emission reduction};

[0014] S6. Taking the evolution stable strategy {active supervision, low-carbon emission reduction, low-carbon emission reduction} of the mature stage as the analysis object, setting the specific values of the cost and benefit variables in step S1, the influence of the initial strategy proportion, the government environmental protection tax collection strength, the government subsidy proportion and the low-carbon emission reduction cost of the port and the shipping company on the evolution stability of the system is analyzed through numerical simulation, and the key driving factors and regulation rules of the evolution of the three parties to the ideal state are obtained.

[0015] Further, in step S3, the construction process of the government's replicated dynamic equation is as follows:

[0016] Let the probability of the government choosing "active supervision" be x, and the probability of choosing "negative supervision" be 1-x; the probability of the port choosing "low-carbon emission reduction" be y, and the probability of choosing "traditional development" be 1-y; the probability of the shipping company choosing "low-carbon emission reduction" be z, and the probability of choosing "traditional development" be 1-z;

[0017] The expected income E x1 of the government "active supervision" is:

[0018]

[0019] The expected income E x2 of the government "negative supervision" is:

[0020]

[0021] The average income E x of the government is:

[0022] E x = xE x1 + (1-x)E x2

[0023] The replicated dynamic equation F(x) of the government is:

[0024]

[0025] Further, in step S3, the process of constructing the replicator dynamic equation of the port is as follows:

[0026] The expected payoff E of the port "low-carbon emission reduction" y1 is:

[0027]

[0028] The expected payoff E of the port "traditional development" y2 is:

[0029] E y2 = xz(-T p )+ x(1-z)(-T p )+(1-x)z(0)+(1-x)(1-z)(0)

[0030] The average payoff E of the port y is:

[0031] E y =yE y1 +(1-y)E y2

[0032] The replicator dynamic equation F(y) of the port is:

[0033]

[0034] Further, in step S3, the process of constructing the replicator dynamic equation of the shipping company is as follows:

[0035] The expected payoff E of the shipping company "low-carbon emission reduction" z1 is:

[0036]

[0037] The expected payoff E of the shipping company "traditional development" z2 is:

[0038] E z2 = xy(-T s )+ x(1-y)(-T s )+(1-x)y(0)+(1-x)(1-y)(0)

[0039] The average payoff E of the shipping company z is:

[0040] E z =zE z1 +(1-z)E z2

[0041] The replication dynamic equation F(z) of the shipping enterprise is:

[0042]

[0043] Further, in step S4, when F(x)=0, dF(x) / dx<0, F(y)=0, dF(y) / dy<0, F(z)=0, dF(z) / dz<0, the three parties are in a stable state.

[0044] Further, the equation of the evolutionary game of the three parties is:

[0045]

[0046] Solve F x (x,y,z)=0, F y (x,y,z)=0, F z (x,y,z)=0, to obtain the pure strategy equilibrium point of the three parties in the evolutionary game process;

[0047] The construction form of the Jacobian matrix is:

[0048]

[0049] By calculating the eigenvalues of the Jacobian matrix at each equilibrium point, if all the eigenvalues are less than 0, then the equilibrium point is an evolutionary stable strategy.

[0050] Further, in step S6, the key driving factors and regulation laws include: the rate of evolution of the three parties to the ideal state is proportional to the initial strategy proportion; the low-carbon emission evolution rate of the port and the shipping enterprise is proportional to the government environmental protection tax collection intensity, the government subsidy proportion, and inversely proportional to the low-carbon emission cost.

[0051] The beneficial effects of the present application are:

[0052] 1. Dynamic evolution perspective: Break through the limitation of traditional static game, depict the evolution process of the three parties' strategies over time through the replication dynamic equation, which is more in line with the actual decision logic of the low-carbon development of the inland port;

[0053] 2. Multivariate quantitative analysis: Systematically integrate key variables such as environmental protection tax, subsidy, cost, etc., to accurately simulate the implementation effect of different policy combinations;

[0054] 3. Staged policy guidance: Provide differentiated suggestions according to the characteristics of the evolution stage, focus on improving the supervision intensity in the initial stage, optimize the subsidy structure in the development stage, and focus on cost control in the mature stage;

[0055] 4. Practical analysis tool: through modular design to realize the whole process automation of parameter input-model calculation-result output, facilitate policy makers to intuitively understand the control mechanism. BRIEF DESCRIPTION OF DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation to the scope. Other related drawings can also be obtained by those skilled in the art without creative labor on the premise of not paying creative labor.

[0057] Figure 1 For y=y * , the government behavior evolution process diagram;

[0058] Figure 2 For 0 * <y

[0059] Figure 3 For y * <1, the government behavior evolution process diagram;

[0060] Figure 4 For x=x * , the port behavior dynamic evolution trend diagram;

[0061] Figure 5 For 0 * <x

[0062] Figure 6 For x * <1, the port behavior dynamic evolution trend diagram;

[0063] Figure 7 For y=y * , the shipping behavior dynamic evolution trend diagram;

[0064] Figure 8 For 0 * <y

[0065] Figure 9 For y * <1, the shipping behavior dynamic evolution trend diagram;

[0066] Figure 10 For the initial stage system evolution path diagram of the equilibrium point E2(1, 0, 0);

[0067] Figure 11 For the development stage system evolution path diagram of the equilibrium point E5(1, 1, 0);

[0068] Figure 12 Evolution path of the development stage system for the equilibrium point E6 (1, 0, 1);

[0069] Figure 13 Evolution path of the mature stage system for the equilibrium point E8 (1, 1, 1);

[0070] Figure 14 Influence of different initial strategy proportions on the stability of system evolution Figure 1 ;

[0071] Figure 15 Influence of different initial strategy proportions on the stability of system evolution Figure 2 ;

[0072] Figure 16 Influence of different initial strategy proportions on the stability of system evolution Figure 3 ;

[0073] Figure 17 Influence of the environmental tax intensity levied by the government on the port on the stability of system evolution when the tax intensity is reduced by 30%;

[0074] Figure 18 Influence of the environmental tax intensity levied by the government on the port on the stability of system evolution when the tax intensity is unchanged;

[0075] Figure 19 Influence of the environmental tax intensity levied by the government on the port on the stability of system evolution when the tax intensity is increased by 30%;

[0076] Figure 20 Influence of the environmental tax intensity levied by the government on shipping on the stability of system evolution when the tax intensity is reduced by 30%;

[0077] Figure 21 Influence of the environmental tax intensity levied by the government on shipping on the stability of system evolution when the tax intensity is unchanged;

[0078] Figure 22 Influence of the environmental tax intensity levied by the government on shipping on the stability of system evolution when the tax intensity is increased by 30%;

[0079] Figure 23 Influence of the government subsidy coefficient on the stability of system evolution when the subsidy intensity is reduced by 50%;

[0080] Figure 24 Influence of the government subsidy coefficient on the stability of system evolution when the subsidy intensity is unchanged;

[0081] Figure 25 Influence of the government subsidy coefficient on the stability of system evolution when the subsidy intensity is increased by 50%;

[0082] Figure 26 Fig. 4 is a diagram showing the influence of the port low-carbon emission reduction cost on the stability of system evolution when the port low-carbon emission reduction cost is reduced by 50%;

[0083] Figure 27 Fig. 5 is a diagram showing the influence of the port low-carbon emission reduction cost on the stability of system evolution when the port low-carbon emission reduction cost is unchanged;

[0084] Figure 28 Fig. 6 is a diagram showing the influence of the port low-carbon emission reduction cost on the stability of system evolution when the port low-carbon emission reduction cost is increased by 50%;

[0085] Figure 29 Fig. 7 is a diagram showing the influence of the shipping enterprise low-carbon emission reduction cost on the stability of system evolution when the shipping enterprise low-carbon emission reduction cost is reduced by 50%;

[0086] Figure 30 Fig. 8 is a diagram showing the influence of the shipping enterprise low-carbon emission reduction cost on the stability of system evolution when the shipping enterprise low-carbon emission reduction cost is unchanged;

[0087] Figure 31 Fig. 9 is a diagram showing the influence of the shipping enterprise low-carbon emission reduction cost on the stability of system evolution when the shipping enterprise low-carbon emission reduction cost is increased by 50%. DETAILED DESCRIPTION

[0088] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0089] An inland port low-carbon development analysis method, comprising the following steps:

[0090] 1. Evolutionary game model construction

[0091] 1.1 Model assumptions

[0092] Assumption 1: The government has two game strategies, i.e. "active supervision" and "passive supervision"; the port and the shipping enterprise have two game strategies, i.e. "low-carbon emission reduction" and "traditional development".

[0093] Assumption 2: The government, the port and the shipping enterprise are all "limited rational" participants, and the optimal decision needs to be made after learning, improving and adjusting through multiple games to achieve equilibrium.

[0094] Assumption 3: Regarding the cost, it is assumed that the additional cost of the port "low-carbon emission reduction" is If the shipping company "low-carbon emission reduction" at this time, the additional cost generated is Among them Assuming that the port "traditional development", the cost generated is the environmental tax T collected by the government p . For the income, the government will subsidize the port according to the additional cost of low-carbon emission reduction according to a certain proportion (0 < α < 1). If the port and shipping both "low-carbon emission reduction", the port enterprise can obtain the low-carbon facility service fee SC paid by the shipping enterprise.

[0095] Assumption 4: For the cost of shipping enterprises, only the shipping enterprise "low-carbon emission reduction" needs to pay the additional cost If both parties "low-carbon emission reduction" at the same time, the additional cost generated is Among them Assuming that the shipping "traditional development", the cost generated is the environmental tax T collected by the government s . For the income of shipping enterprises, the government will subsidize the low-carbon emission reduction of shipping enterprises according to the additional cost according to a certain proportion (0 < α < 1).

[0096] Assumption 5: When the government "actively supervises", the supervision cost is C G , and the benefit is good social reputation R. With the implementation of the double carbon strategy, the port environmental problem is increasingly concerned by the society, and the port-city integration development has also become one of the local government's performance evaluation, that is

[0097] Assumption 6: When the government "negatively supervises", the port "low-carbon emission reduction", and the shipping enterprise "traditional development", the government will suffer a loss of social reputation If the shipping enterprise "low-carbon emission reduction", the port "traditional development", the government's loss of social reputation is If both parties "traditional development", the loss is

[0098] Assumption 7: The probability of the government, port and shipping enterprise taking ideal state (active supervision, low-carbon emission reduction, low-carbon emission reduction) decision respectively is x, y, z, and x, y, z ∈ [0, 1].

[0099] The related variables and explanations are shown in Table 1.

[0100] Table 1 Variables and their explanations

[0101]

[0102] 1.2 Model construction

[0103] According to the model assumptions and variables, the payoff matrix of the government in {active regulation (x), passive regulation (1-x)}, the port in {low-carbon reduction (y), traditional development (1-y)}, and the shipping company in {low-carbon reduction (z), traditional development (1-z)} strategy set is obtained, as shown in Table 2.

[0104] Table 2 Payoff matrix

[0105]

[0106] 2. Evolutionary game analysis

[0107] 2.1 Replicator dynamic equation According to Table 2, the expected payoffs E x1 , E x2 and the average payoff E x of the government in "active regulation" and "passive regulation" are respectively:

[0108]

[0109] E x = xE x1 + (1-x)E x2 (3)

[0110] According to the evolutionary game theory, the replicator dynamic equation of the government is:

[0111] The expected payoffs E y1 , E y2 and the average payoff E y of the port in "low-carbon reduction" and "traditional development" are respectively:

[0112]

[0113] E y2 = xz(-T p )+x(1-z)(-T p )+(1-x)z(0)+(1-x)(1-z)(0) (6)

[0114] E y = yE y1 +(1-y)E y2 (7)

[0115] Similarly, the replicator dynamic equation is:

[0116] The expected payoffs E z1 , E z2 and the average payoff E z of the shipping company in "low-carbon reduction" and "traditional development" are respectively:

[0117]

[0118] E z2 = xy(-T s ) + x(1 - y)(-T s ) + (1 - x)y(0) + (1 - x)(1 - y)(0) (10)

[0119] E z = zE z1 + (1 - z)E z2 (11)

[0120] Similarly, its replication dynamic equation is:

[0121]

[0122] 2.2 Analysis of Evolution Trend of Three Parties

[0123] According to the stability principle of the replication dynamic equation, when F(x) = 0, dF(x) / dx < 0, F(y) = 0, dF(y) / dy < 0, F(z) = 0, dF(z) / dz < 0, the three parties are in a stable state.

[0124] For the government, let F(x) = 0, the solution may be a stable equilibrium point:

[0125] (1) When , F(x) = 0, indicating that the points on the x-axis are in a stable state, i.e., the government has reached a stable equilibrium state.

[0126] (2) When y ≠ y * , there are two cases:

[0127] 1) When 0 < y < y * , dF(x) / dx| x＝0 < 0, dF(x) / dx| x＝1 > 0, at this time x = 0 is the equilibrium point of the government, i.e., the government will eventually develop towards "negative supervision".

[0128] 2) When y * < y < 1, dF(x) / dx| x＝0 > 0, dF(x) / dx| x＝1 < 0, at this time x = 1 is the equilibrium point of the government, i.e., the government will eventually develop towards "active supervision".

[0129] According to the above evolution trend analysis, the evolution results are shown in a three-dimensional coordinate system, and the dynamic evolution trend of the government is obtained, as shown in Figures 1-3 .

[0130] For the port, let F(y) = 0, the solution can be a stable equilibrium point:

[0131] (1) When , F(y) = 0, it means that the points on the y-axis are in a stable state, that is, the port's strategy selection does not change over time.

[0132] (2) When x≠x * , there are two cases:

[0133] 1) When 0 < x < x * , dF(y) / dy| y＝0 < 0, dF(y) / dy| y＝1 > 0, at this time y = 0 is the equilibrium point of the port, that is, the port will eventually develop towards "traditional development".

[0134] 2) When x * < x < 1, dF(y) / dy| y＝0 > 0, dF(y) / dy| y＝1 < 0, at this time y = 1 is the equilibrium point of the port, that is, the port will eventually develop towards "low-carbon emission reduction".

[0135] According to the above evolution trend analysis, the evolution results are shown in a three-dimensional coordinate system, and the dynamic evolution trend of the port's behavior can be obtained, as shown in Figures 4-6 .

[0136] For shipping companies, let F(z) = 0, the solution can be a stable equilibrium point:

[0137] (1) When , F(z) = 0, it means that the points on the z-axis are in a stable state, that is, the shipping company's strategy selection does not change over time.

[0138] (2) When y≠y * , there are two cases:

[0139] 1) When 0 < y < y * , dF(z) / dz| z＝0 < 0, dF(z) / dz| z＝1 > 0, at this time z = 0 is the equilibrium point of the shipping company, that is, the shipping company will develop towards "traditional development".

[0140] 2) When y * < y < 1, dF(z) / dz| z＝0 > 0, dF(z) / dz| z＝1 < 0, at this time z = 1 is the equilibrium point of the shipping company, that is, the shipping company will develop towards "low-carbon emission reduction".

[0141] According to the above evolution trend analysis, the evolution result is shown in a three-dimensional coordinate system, and the dynamic evolution trend of the shipping party behavior can be obtained, as shown in the following figure. Figures 7-9

[0142] 2.3 Evolution stability analysis of equilibrium point

[0143] According to the above analysis, the equation of the three-party evolution game is:

[0144]

[0145] Solving F x (x,y,z)=0, F y (x,y,z)=0, F z (x,y,z)=0, the eight pure strategy equilibrium points of the three-party subject in the evolution game process can be obtained, i.e. E1(0,0,0), E2(1,0,0), E3(0,1,0), E4(0,0,1), E5(1,1,0), E6(1,0,1), E7(0,1,1), and E8(1,1,1).

[0146] The Friedman theory is used to determine the stable equilibrium state of the three-party subject, that is, when the eigenvalues of the Jacobian matrix of the equilibrium point are all less than 0, the equilibrium point is the evolution stable point strategy of the system. According to formula (13), the Jacobian matrix is obtained as:

[0147]

[0148] According to the Jacobian matrix, the eigenvalues are calculated, as shown in Table 3.

[0149] Table 3 Eigenvalues of Jacobian matrix

[0150]

[0151] Since the eigenvalues of the equilibrium points E1(0,0,0), E3(0,1,0), E4(0,0,1), and E7(0,1,1) are all positive, they are unstable points. According to the development history of low-carbon port, the above four equilibrium points are divided into three stages, and the stability of the above four equilibrium points is analyzed.

[0152] Initial stage: the equilibrium point E2(1,0,0) is an evolution stable strategy. With the proposal of the double carbon strategy, the government begins to develop low-carbon ports by formulating relevant policies, but at this time the government's supervision is relatively low. The cost of low-carbon emission reduction strategy of the port and shipping enterprises is higher than the environmental tax collected by the government under the condition of enjoying government subsidies, and both the port and the shipping enterprises tend to traditional development, and the evolution path is as shown in the following figure. Figure 10

[0153] ​​Development stage: Equilibrium points E5 (1, 1, 0) and E6 (1, 0, 1) are evolutionarily stable strategies. With the increasing environmental impact and the continuous promotion of the double carbon strategy, the government's regulatory efforts gradually strengthen, and the port and shipping enterprises begin to gradually transition from traditional development to low-carbon emission reduction. For equilibrium point E5, at this time, the environmental tax collected by the government is lower than the actual increase cost (the sum of government subsidies and service fees) of the shipping enterprise when both parties carry out low-carbon emission reduction, and the shipping enterprise chooses traditional development; the port chooses low-carbon emission reduction because the port's individual emission reduction cost is lower than the environmental tax under government subsidies, and the evolution path is as shown in Figure 11 For equilibrium point E6, for the same reason, at this time, the environmental tax collected by the government is lower than the time increase cost (the difference between government subsidies and service fees) of the port when both parties carry out low-carbon emission reduction, and the port chooses traditional development; the shipping enterprise chooses low-carbon emission reduction because the shipping enterprise's individual emission reduction cost is lower than the environmental tax under government subsidies, and the evolution path is as shown in Figure 12 .

[0154] Mature stage: Equilibrium point E8 (1, 1, 1) is an evolutionarily stable strategy. With the gradual improvement of the government's regulatory measures, the port and the shipping enterprise have completed the transition from traditional development to low-carbon emission reduction under the perfect reward and punishment policy. This stage is also the ideal stage of the entire system. At this time, the actual cost of the port and the shipping enterprise choosing low-carbon emission reduction under government subsidies is lower than the environmental tax collected by the government, and both parties tend to choose the low-carbon emission reduction strategy. The government's active regulation of the port and the shipping enterprise has played a good role, and the evolution path is as shown in Figure 13 .

[0155] 3. Numerical simulation of evolutionary game model

[0156] The present application applies equilibrium point E8 (1, 1, 1) to analyze the influence of initial strategy proportion and external variables on the evolution stability of the system. It is assumed that the port's low-carbon emission reduction measures are realized through the application and promotion of port shore power technology. Port shore power is to replace the burning of fuel oil by using electricity to maintain basic activities during ship berthing, so as to reduce fuel consumption and carbon emissions. Finally, the parameters of the evolutionary game model of the present application are set as shown in the following table.

[0157] Table 4 Numerical simulation parameters

[0158]

[0159] 3.1 Influence of initial strategy on evolution stability of system

[0160] Figures 14-16As shown, the convergence curves of the game strategies of the government, port, and shipping companies will not overlap or intersect before the system reaches stability, indicating that the evolution paths are dependent. Changes in the initial strategies have a certain impact on the stable convergence rate of the system, and the closer the initial strategies of the three parties are to the equilibrium point, the faster their convergence rate. This suggests that the initial strategies are crucial for the three parties to converge towards the final ideal equilibrium point E8(1,1,1). Therefore, the government should implement the dual-carbon strategy, continuously improve the relevant reward and punishment policies for low-carbon ports, and both ports and shipping companies should actively respond to the government's call and cooperate in low-carbon emission reduction to form a virtuous cycle.

[0161] 3.2 The impact of external variables on system evolution and stability

[0162] Stability conditions of the ideal equilibrium point E8(1,1,1) It is known that the system will gradually converge to this strategy only when the benefits to the government, port, and shipping parties outweigh the costs. Therefore, this invention combines different scenarios and influencing factors to further analyze the impact of external variables on the system's evolutionary stability.

[0163] 3.2.1 Environmental taxes levied by the government

[0164] To further analyze the impact of the government's environmental tax collection efforts on ports and shipping companies on the evolution of the game among the three parties, let T... p T s Fluctuation of 30% up or down, the result is as follows Figures 17-22 As shown.

[0165] Depend on Figures 17-19 It can be seen that the environmental protection tax T p The environmental tax has a significant impact on the convergence curve of the port evolution game; the higher the environmental tax, the faster the port evolution game converges to the stable equilibrium point. Environmental tax T p The environmental tax T has a certain impact on the convergence curve of the shipping game. p The convergence rate is inversely proportional to the cost, mainly because when both the port and the shipping company adopt low-carbon emission reduction strategies, the shipping company needs to pay the port a low-carbon facility and equipment service fee (SC). Choosing low-carbon emission reduction means that the shipping company needs to bear more costs.

[0166] Depend on Figures 20-22 It can be seen that the environmental protection tax T s Environmental taxes have a significant impact on the convergence curve of shipping evolutionary games. Higher environmental taxes lead to a faster rate of stable convergence towards the equilibrium point. When the intensity of environmental taxes decreases to a certain level, shipping companies tend to choose traditional development strategies. The sensitivity of shipping companies to environmental taxes lies in the comparison between the costs of adopting low-carbon emission reduction strategies and the costs of the environmental taxes themselves. Environmental tax T sThe environmental tax T has a certain impact on the convergence curve of the port evolution game. s The convergence rate of port evolution is also directly proportional to the port's evolution rate. The main reason is that when both the port and the shipping company adopt low-carbon emission reduction strategies, the port can charge the shipping company a low-carbon facility and equipment service fee (SC). Choosing low-carbon emission reduction means that the port can obtain more revenue.

[0167] 3.2.1 Government subsidy ratio coefficient

[0168] To further analyze the impact of the government's subsidy ratio for ports and shipping on the evolution of the game among the three parties, the subsidy ratio α is set to fluctuate by 50%.

[0169] Depend on Figures 23-25 It is evident that government subsidies have a positive impact on ports and shipping; the greater the subsidy, the faster the convergence rate of choosing low-carbon emission reduction strategies. For shipping companies, when subsidies are reduced by 50%, they directly choose traditional development. Although ports initially showed a trend towards low-carbon emission reduction, they ultimately opted for traditional development. Therefore, government subsidies have a positive impact on encouraging both ports and shipping companies to choose low-carbon emission reduction strategies, primarily because both parties hope to reduce the costs of low-carbon emission reduction through government subsidies.

[0170] 3.2.2 Costs of Low-Carbon Emission Reduction in Ports and Shipping

[0171] To further analyze the impact of the three-way game evolution of low-carbon emission reduction costs for ports and shipping companies individually, let... Fluctuation of 30% up or down, the result is as follows Figures 26-31 As shown.

[0172] Depend on Figures 26-28 It is evident that the cost of low-carbon emission reduction alone significantly impacts port decision-making. When this cost decreases, the convergence rate of low-carbon emission reduction at ports accelerates considerably. Conversely, as costs increase, not only does the convergence rate decrease, but ports initially tend towards traditional development models. For shipping companies, the trend is the opposite of that of ports because they do not want to excessively increase their cost burden. Furthermore, when both ports and shipping companies engage in low-carbon emission reduction, shipping companies must pay service fees to ports for low-carbon facilities and equipment.

[0173] Depend on Figures 29-31It can be seen that the cost of low-carbon emission reduction of shipping enterprises alone has a greater impact on the decision-making of shipping enterprises. The smaller the cost is, the faster the convergence speed of the evolutionary game curve of shipping enterprises is. When the cost increases, not only the convergence speed decreases, but also the shipping enterprises are more inclined to the traditional development mode at the beginning. The cost has a smaller impact on the decision-making of the port, but its trend is the same as that of the shipping enterprises. The main reason is that the reduction of the cost can promote the selection of low-carbon emission reduction by shipping enterprises. When both parties choose low-carbon emission reduction, the port can collect an additional low-carbon facility service fee, so it will also tend to choose low-carbon emission reduction.

[0174] Similarly, and The influence on the stability of the evolutionary game of the three parties is similar, so it is not described in detail in the text.

[0175] In summary:

[0176] (1) When the benefits of the three parties participating in the subject of "active supervision" and "low-carbon emission reduction" are greater than those of "negative supervision" and "traditional development", the three-party decision-making develops towards the ideal state of "active supervision" and "low-carbon emission reduction".

[0177] (2) The evolutionary rate of the three parties towards the ideal decision of "active supervision" and "low-carbon emission reduction" is proportional to the initial strategy proportion of the three parties.

[0178] (3) The low-carbon emission reduction evolutionary rate of the port and the shipping enterprise is proportional to the environmental protection tax collected by the government and the subsidy proportion coefficient. The stronger the government supervision (the higher the environmental protection tax, the higher the subsidy proportion coefficient), the faster the low-carbon emission reduction evolutionary convergence speed is.

[0179] (4) The low-carbon emission reduction evolutionary rate of the port and the shipping enterprise is inversely proportional to the low-carbon emission reduction cost. The lower the low-carbon emission reduction cost is, the faster the low-carbon emission reduction evolutionary convergence speed is.

[0180] The research conclusion of the application can provide a certain theoretical basis for the formulation of government regulation policies in the development process of low-carbon ports.

[0181] The above only describes the preferred embodiments of the present application and does not limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An inland port low-carbon development analysis method, characterized in that, The method comprises the following steps: S1. Constructing an evolutionary game model involving the government, the port, and shipping enterprises, and clearly defining the strategy set, cost and benefit variables, and model assumptions of the three parties; wherein the strategy set of the government is {active supervision, passive supervision}, the strategy set of the port is {low-carbon emission reduction, traditional development}, and the strategy set of the shipping enterprises is {low-carbon emission reduction, traditional development}; The cost and benefit variables at least include: the port's individual low-carbon emission reduction cost The port and shipping company's joint low-carbon emission reduction cost The shipping company's individual low-carbon emission reduction cost The shipping company and port's joint low-carbon emission reduction cost The government's active regulation cost C G , the government's active regulation social reputation benefit R, the social reputation loss under different scenarios of the government's passive regulation and The government's subsidy ratio a, the environmental protection tax T levied by the government on the port p , the environmental protection tax T levied by the government on the shipping company s , the low-carbon facility and equipment service fee SC paid by the shipping company to the port, the environmental impact cost ED of the traditional development of both parties, the social benefit WS of the low-carbon emission reduction of both parties; the model assumptions at least include: all the three parties are bounded rationality, and need to adjust the decisions through multiple game learning; and S2. Based on the strategy set and variables determined in step S1, a payment matrix of the three parties is constructed, which covers the payment values of the government, the port, and the shipping enterprises under 8 decision combinations, and the 8 decision combinations are {active supervision, low-carbon emission reduction, low-carbon emission reduction}, {active supervision, low-carbon emission reduction, traditional development}, {active supervision, traditional development, low-carbon emission reduction}, {active supervision, traditional development, traditional development}, {passive supervision, low-carbon emission reduction, low-carbon emission reduction}, {passive supervision, low-carbon emission reduction, traditional development}, {passive supervision, traditional development, low-carbon emission reduction}, and {passive supervision, traditional development, traditional development}; S3. Based on the payment matrix in step S2, the expected income and average income of the government when choosing "active supervision" and "passive supervision" are calculated, the expected income and average income of the port when choosing "low-carbon emission reduction" and "traditional development" are calculated, the expected income and average income of the shipping enterprises when choosing "low-carbon emission reduction" and "traditional development" are calculated, and the replication dynamic equations of the three parties are derived according to the evolutionary game theory; S4. The replication dynamic equations obtained in step S3 are subjected to evolutionary trend analysis, the conditions for the strategy stability of the three parties are solved, and the evolutionary stable strategies of the government, the port, and the shipping enterprises under different conditions are determined; S5. The pure strategy equilibrium points of the evolutionary game equation set of the three parties are solved, the Jacobian matrix is constructed, the eigenvalues of each equilibrium point are calculated, the evolutionary stability of each equilibrium point is judged, and the initial stage, the development stage, and the mature stage of the system evolution are divided, wherein the evolutionary stable strategy of the initial stage is {passive supervision, traditional development, traditional development}, the evolutionary stable strategies of the development stage are {active supervision / passive supervision, low-carbon emission reduction, traditional development} and {active supervision / passive supervision, traditional development, low-carbon emission reduction}, and the evolutionary stable strategy of the mature stage is {active supervision, low-carbon emission reduction, low-carbon emission reduction}; S6. Taking the evolutionary stable strategy {active supervision, low-carbon emission reduction, low-carbon emission reduction} of the mature stage as the analysis object, setting the specific values of the cost and benefit variables in step S1, and through numerical simulation, the influence of the initial strategy proportion, the government environmental protection tax collection strength, the government subsidy proportion, and the low-carbon emission reduction cost of the port and the shipping enterprises on the evolutionary stability of the system is analyzed respectively, and the key driving factors and regulation rules of the evolution of the three parties to the ideal state are obtained.

2. The method according to claim 1, wherein: In step S3, the construction process of the replication dynamic equation of the government is as follows: Let the probability of the government choosing "active supervision" be x, and the probability of the government choosing "passive supervision" be 1-x; let the probability of the port choosing "low-carbon emission reduction" be y, and the probability of the port choosing "traditional development" be 1-y; let the probability of the shipping enterprises choosing "low-carbon emission reduction" be z, and the probability of the shipping enterprises choosing "traditional development" be 1-z. The expected return E of the government's "active regulation" x1 is: The expected return E of the government's "negative regulation" x2 is: The average revenue E of the government is: x E = (1 - t) * (1 - s) * E x = xE x1 + (1 - x)E x2 The replication dynamic equation F(x) of the government is:

3. The method according to claim 1, wherein: In step S3, the replication dynamic equation of the port is constructed as follows: The expected return E of the "low-carbon emission reduction" of the port y1 is: The expected return E of the "traditional development" of the port y2 is: E y2 = xz(-T p )+x(1-z)(-T p )+(1-x)z(0)+(1-x)(1-z)(0) The average revenue E of the port is given by: y E = (P + C) / T E y = yE y1 + (1 - y)E y2 The replication dynamic equation F(y) of the port is:

4. The method for analyzing the low-carbon development of an inland river port according to claim 1, characterized in that: In step S3, the replication dynamic equation of the shipping company is constructed as follows: The expected revenue E of shipping enterprises "low carbon emission reduction" z1 is: Expected return E of the shipping company "traditional development" z2 is: E z2 = xy(-T s )+ x(1 - y)(-T s )+(1 - x)y(0)+(1 - x)(1 - y)(0) The average revenue E of shipping companies is given by: z E = (1 - p) * V E z = zE z1 + (1 - z)E z2 The replication dynamic equation F(z) of the shipping company is:

5. The method for analyzing the low-carbon development of an inland river port according to claim 1, characterized in that: In step S4, when F(x) = 0, dF(x) / dx < 0, F(y) = 0, dF(y) / dy < 0, F(z) = 0, dF(z) / dz < 0, the three parties are in a stable state.

6. The method for analyzing the low-carbon development of an inland river port according to claim 1, characterized in that: The equation of the evolutionary game of the three parties is: Solving F x (x, y, z) = 0, F y (x, y, z) = 0, F z (x, y, z) = 0, get the pure strategy equilibrium point of the three-party body in the evolutionary game process; The Jacobian matrix is constructed as follows: By calculating the eigenvalues of the Jacobian matrix at each equilibrium point, if all the eigenvalues are less than 0, the equilibrium point is an evolutionary stable strategy.

7. The method for analyzing the low-carbon development of an inland river port according to claim 1, characterized in that: In step S6, the key driving factors and regulation laws include: the rate of evolution of the three parties towards the ideal state is proportional to the proportion of their initial strategies; the evolution rate of low-carbon emission reduction of the port and the shipping company is proportional to the government's environmental tax collection and the government's subsidy proportion, and is inversely proportional to the low-carbon emission reduction cost of itself.

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