Ecological protection and restoration engineering risk analysis method based on analytic hierarchy process

Abstract

The invention discloses an ecological protection and restoration engineering risk analysis method based on an analytic hierarchy process, which comprises the following steps of: firstly, collecting data, identifying engineering risk factors, and establishing an evaluation index system which comprises a target layer, a criterion layer and an index layer, the subordination relationship between the step structure of each layer and each factor is shown in a block diagram form; then determining the index weight of each level, and constructing a pairwise comparison judgment matrix of different levels; and finally, calculating sorting weights of the relative importance of all elements relative to the target layer from the highest layer to the lowest layer by using analytic hierarchy process calculation software, and checking the consistency of each layer to obtain a total sorting result of the engineering risk indexes. According to the method, the ecological protection and restoration engineering risk can be reasonably analyzed and evaluated, and the engineering risk management can be effectively carried out by an engineering implementation mechanism.

Description

Technical Field

[0001] The present invention relates to the field of engineering risk analysis, and more specifically to an ecological protection and restoration engineering risk analysis method based on hierarchical analysis method. Background Art

[0002] There are many factors that affect the risk of ecological protection and restoration projects, and the factors are interrelated, the risks interact with each other, and the project risks accompany the entire process of project implementation. In order to improve the performance and governance level of ecological protection and restoration projects, it is necessary to predict, identify, and analyze project risks during the implementation of the project, strengthen project risk management, and take corresponding preventive measures in a timely manner to avoid the occurrence of project risks. The present invention can reasonably analyze the risks of ecological protection and restoration projects, and the evaluation results are objective and accurate, which is convenient for project implementation agencies to effectively manage project risks. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a risk analysis method for ecological protection and restoration projects based on the analytic hierarchy process. On the basis of identifying the risk factors of ecological protection and restoration projects, indicators are screened and determined to evaluate the degree of influence of each risk factor in the implementation of mountain ecological protection and restoration projects, and a set of scientific, reasonable and practical engineering risk evaluation indicator system is established, which can effectively control or reduce engineering risks and minimize the uncertainty brought to engineering projects by risk factors.

[0004] The technical purpose of the present invention is achieved through the following technical solutions.

[0005] A risk analysis method for ecological protection and restoration projects based on the analytic hierarchy process is carried out in the following steps:

[0006] Step 1: Collect data, identify engineering risk factors, and establish an evaluation index system, including the target layer, criterion layer, and indicator layer. Each layer is composed of several factors, and a block diagram is used to show the hierarchical structure of each level and the subordinate relationship of each factor.

[0007] In step 1, based on data analysis and field research, a risk list for ecological protection and restoration projects is compiled, important risk factors are identified and summarized, and a risk assessment index system for ecological protection and restoration projects is derived.

[0008] Step 2: Based on the risk assessment index system obtained in step 1, construct a pairwise comparison judgment matrix. The judgment matrix A uses a comparison standard (a ij ) is used to express the understanding of the relative importance (or advantages and disadvantages, preferences, etc.) of the th factor and the th factor in a certain level. ij Generally, the scale method of 1-9 and its reciprocal is adopted, see Table 1 for details.

[0009] Table 1. AHP risk analysis score table

[0010]

[0011] Step 3: Hierarchical single sorting and consistency test. Hierarchical single sorting is to calculate the ranking weight of each indicator relative to the previous layer factor associated with it after establishing the judgment matrix. Hierarchical single sorting can be reduced to finding the maximum eigenvalue λ of the judgment matrix A. max and its eigenvector W, that is, AW = λ max W, after normalizing W, we get W = [w 1 , w 2 ,......,w n ] is the ranking weight of each factor.

[0012] In order to control the possibility of erroneous calculation results due to inconsistent comparison scales when comparing two factors in the hierarchical single sorting process, a consistency check is required during the single sorting process. j, k both have a ij ·a jk =a ik , then A is called the consistency judgment matrix. The consistency test method is:

[0013] Calculate the consistency index CI = (λ max -n) / (n-1), where n is the order of the judgment matrix.

[0014] Calculate the average random consistency index RI. RI is obtained by taking the arithmetic mean after repeatedly calculating the eigenvalues ​​of the random judgment matrix. The following table gives the average random consistency index of 1 to 10 dimensional matrices calculated 1000 times. See Table 2 for details:

[0015] Table 2 The values ​​of the average random consistency index RI and the corresponding critical eigenvalues

[0016]

[0017] Calculate the consistency ratio index CR = CI / RI. When CR < 0.1, the judgment matrix has satisfactory consistency. If it is not satisfied, the value of the factor in matrix A needs to be adjusted.

[0018] Step 4: The total ranking of the levels needs to be done from top to bottom. The calculation form is relatively simple in table form. Suppose there are two adjacent levels, and the previous level A contains m factors a 1 , a 2 , ..., a m , the next level B contains n elements b 1 , b 2 , ..., bn The total ranking weight of the level A factor is w 1 , w 2 , ..., w n , the hierarchical single-rank weight vector of factor bi in level B with respect to factor ai in level A is (b 1 i , b 2 i , ..., b n i ) T (i=1, 2, ..., m). Element b in level B j The combined weight value is

[0019] Step 5, the consistency test of the single hierarchical ranking can ensure that the comparison scale used when comparing the factors of each layer is basically consistent, but there may be differences between the layers and such differences will be amplified in the hierarchical total ranking as the layers accumulate. Therefore, it is necessary to test whether such differences meet the requirements in the overall analysis model. This test is called the consistency test of the hierarchical total ranking. Let CI be the consistency index of the hierarchical total ranking, and RI be the random consistency index of the hierarchical total ranking. Its calculation formula is

[0020]

[0021] CI i A i The consistency index of the corresponding judgment matrix in level B.

[0022]

[0023] RI i A i The random consistency index of the judgment matrix in the corresponding B level.

[0024] In the same way, the total consistency index CR = CI / RI. When CR < 0.1, the result of the total hierarchical ranking is considered to have satisfactory consistency. If the consistency condition is not met, the judgment matrix needs to be adjusted. The final result of AHP is to obtain the priority weights of each risk indicator relative to the total goal, and analyze the risk assessment results based on this.

[0025] The present invention firstly adopts a comprehensive method to determine specific statistical indicators on the basis of subdividing the measurement objects and targets. The specific method is to conduct field research in the case areas, conduct sample questionnaire surveys, and collect as much indicator data as possible in combination with the characteristics and implementation status of the ecological protection and restoration project; then, redundant indicators are eliminated through expert consultation and theoretical analysis, and the indicators are merged according to the corresponding indicator system framework; finally, a general indicator system for risk analysis of ecological protection and restoration projects is obtained, and the ranking weights of the relative importance of all elements relative to the target layer are calculated layer by layer from the highest layer to the lowest layer using the hierarchical analysis method. The present invention can provide a method for risk analysis and evaluation of ecological protection and restoration projects, and provide a reference for risk management decision-making of ecological protection and restoration projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flow chart of a risk analysis method for ecological protection and restoration projects based on the analytic hierarchy process of the present invention;

[0027] Figure 2 For the present invention B 1 -C-level judgment matrix indicators corresponding to the eigenvector and maximum eigenvalue calculation diagram;

[0028] Figure 3 For the present invention B 2 -C-level judgment matrix indicators correspond to eigenvectors and maximum eigenvalue calculation diagrams. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described below through specific embodiments.

[0030] A risk analysis method for ecological protection and restoration projects based on the analytic hierarchy process is carried out in the following steps:

[0031] Step 1: Collect data, identify engineering risk factors, and establish an evaluation index system, including the target layer, criterion layer, and indicator layer. Each layer is composed of several factors, and a block diagram is used to show the hierarchical structure of each level and the subordinate relationship of each factor.

[0032] Step 11: Collect ecological protection and restoration project design and engineering data from the project management department, consult with experts and leaders in the ecological restoration project industry, develop a more detailed ecological protection and restoration project engineering risk survey form, conduct on-site investigations in each project area, and conduct sample surveys of farmers, township staff, and engineering and technical personnel.

[0033] Step 12. Based on the analysis of data and field research, combined with risk classification, a risk list is compiled, important risk factors are identified and summarized, and an evaluation index system is established to divide engineering risks into three levels, including project engineering risks, risk classification (internal and external risks), risk types based on internal and external risks, and the lowest level specific engineering risk evaluation index system as shown in Table 3.

[0034] Table 3 Risk assessment index system for ecological protection and restoration projects

[0035]

[0036] Step 2: Invite industry experts familiar with ecological protection and restoration projects, as well as persons in charge and engineers of related industries, to determine the indicator weights of the identified risk factors by comparing different factors pairwise based on a comprehensive consideration of the probability of risk occurrence and the degree of impact, and construct judgment matrices at different levels. The parameter tables of the judgment matrices at each level are shown in Tables 4, 5, and 6.

[0037] Table 4 AB level judgment matrix parameter table

[0038]

[0039] Table 5 B 1 -C-level judgment matrix parameter table

[0040]

[0041] Table 6 B 2 -C-level judgment matrix parameter table

[0042]

[0043] Step 3: Hierarchical single sorting and consistency test. Hierarchical single sorting is to calculate the ranking weight of each indicator relative to the previous layer factor associated with it after establishing the judgment matrix. 1 -C, B 2 -C level involves many indicators and factors, and the calculation process is cumbersome, so the AHP software system is used to calculate the judgment matrix. According to the parameters in Table 4, the geometric mean W of each row of the judgment matrix is ​​calculated and normalized. The calculation result W 1 =0.333,W 2 =0.667, calculate the maximum characteristic root λ of the judgment matrix max =2, check the previous table RI = 0, CR = 0 < 0.1, so the AB hierarchical judgment matrix meets the consistency test requirements, B 1 -C, B 2 -C level single sort calculation results see Figure 2 and 3 , B1 -C The consistency test results of the hierarchy are CI = 0.072, RI = 1.410, CR = 0.051 < 0.1; B 2 -The consistency test results of the C level are CI=0.069, RI=1.450, CR=0.048<0.1, all of which meet the consistency test requirements.

[0044] Step 4: The total hierarchical ranking needs to be carried out layer by layer from top to bottom. It can be seen from the output results of the above-mentioned hierarchical analysis software that the judgment matrices at each level have satisfactory consistency. It can be concluded that the constructed matrix selection is relatively scientific and reasonable, and it is operational. Therefore, the total hierarchical ranking of the weights of the risk assessment indicators of ecological protection and restoration projects is shown in Table 7.

[0045] Table 7: Overall ranking of weight levels of each indicator

[0046]

[0047] Step 5, consistency test of total hierarchical ranking, the output results of the AHP software are CI = 0.070, RI = 1.437, CR = 0.049 < 0.1, which meets the consistency test requirements. According to the risk degree calculated by the AHP, that is, the total hierarchical ranking result of the indicator weight, the size of various risks that may exist in the whole process management of ecological protection and restoration projects can be obtained, and then the project risk assessment analysis and response can be carried out in a targeted manner.

[0048] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by those skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. A risk analysis method for ecological protection and restoration projects based on analytic hierarchy process. It is characterized in that Follow the steps below: Step 1: Collect data, identify engineering risk factors, and establish an evaluation index system, including the target layer, criterion layer, and indicator layer. Each layer is composed of several factors, and a block diagram is used to show the hierarchical structure of each level and the subordinate relationship of each factor; Step 2: Based on the risk assessment index system obtained in step 1, construct a pairwise comparison judgment matrix. The judgment matrix A uses a comparison standard (a ij ) is used to express the understanding of the relative importance (or advantages and disadvantages, preferences, etc.) of the th factor and the th factor in a certain level; Step 3: Hierarchical single sorting and its consistency test. Hierarchical single sorting is to calculate the ranking weight of each indicator relative to the upper layer factor associated with it after establishing the judgment matrix. In order to control the wrong calculation results caused by inconsistent comparison scales when comparing the factors in the hierarchical single sorting process, a consistency test is required during the single sorting. Step 4: The total hierarchical sorting needs to be done from top to bottom. There are two adjacent hierarchical levels. The previous hierarchical level A contains m factors a. 1 , a 2 , ..., a m , the next level B contains n elements b 1 , b 2 , ..., b n The total ranking weight of the level A factor is w 1 , w 2 , ..., w n , factor b in level B i About factor a in level A i The hierarchical single-rank weight vector is (b 1 i , b 2 i , ..., b n i ) T (i=1, 2, ..., m). Element b in level B j The combined weight value is Step 5, the consistency test of single hierarchical ranking can ensure that the comparison scale used when comparing factors at each level is basically consistent, but there may be differences between levels and such differences will be magnified in the total hierarchical ranking as the levels accumulate. Therefore, it is necessary to test whether such differences meet the requirements in the overall analysis model.

2. According to the risk analysis method of ecological protection and restoration engineering based on hierarchical analysis method as described in claim 1, It is characterized in that In step 1, based on the analysis of data and field research, combined with risk classification, a risk list is compiled, important risk factors are identified and summarized, and an evaluation index system is established to divide engineering risks into three levels, including project engineering risks, risk classification (internal and external risks), risk types based on internal and external risks, and the lowest level of specific engineering risk evaluation index system.

3. According to the risk analysis method of ecological protection and restoration engineering based on hierarchical analysis method as claimed in claim 1, It is characterized in that In step 3, the hierarchical single sorting can be reduced to finding the maximum eigenvalue λ of the judgment matrix A max and its eigenvector W, that is, AW = λ max W, after normalizing W, we get W = [w 1 , w 2 ,......,w n ] is the ranking weight of each factor. Both have a ij ·a jk =a ik , then A is called the consistency judgment matrix, and the consistency test method is: Calculate the consistency index CI = (λ max -n) / (n-1), where n is the order of the judgment matrix, Calculate the average random consistency index RI, which is obtained by taking the arithmetic mean after repeatedly calculating the eigenvalues ​​of the random judgment matrix.

4. According to the risk analysis method of ecological protection and restoration engineering based on hierarchical analysis method as claimed in claim 1, It is characterized in that In step 5, CI is the consistency index of the total hierarchical order, and RI is the random consistency index of the total hierarchical order. The calculation formula is: CI i A i The corresponding consistency index of the judgment matrix in level B is, RI i A i The random consistency index of the judgment matrix in the corresponding B level.

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