A method and apparatus for designing a drainage area pipeline

Abstract

The application discloses a kind of drainage area pipeline design method and device, according to non-dominated sorting genetic algorithm to the iteration update of regional design scheme, and not first the regional design scheme is converted into SWMM model, can exclude the factor that due to SWMM model and lead to the speed reduction in iteration process.Further the regional design scheme includes multiple factors that each pipe needs to be designed in drainage pipeline design, multiple factors can be updated simultaneously when iteration update.It can be comprehensive to analyze the importance of the factor to be planned and designed, obtain important design factors in drainage pipeline design as pipe parameter.Again iteration update generates multiple design schemes, by setting multiple regional design schemes, the update iteration mode of the content of solution space of regional design scheme is planned, to increase the number of regional design scheme to reduce the amount of calculation, simultaneously optimize all pipe parameters, obtain the final drainage regional design scheme.

Description

Technical Field

[0001] This invention relates to the field of municipal construction design, and more particularly to a method and apparatus for designing drainage area pipelines. Background Technology

[0002] With the development of urban construction, the planning and design of drainage systems are becoming increasingly complex. Using ordinary manual methods to design and plan drainage pipes will result in a large amount of calculation, design difficulties, slow output, and large errors in the results.

[0003] Existing technologies employ computer simulation-assisted drainage pipeline design. While SWMM models are used to simulate parameters such as rainfall, SWMM models have numerous parameters and are complex. Building a model from existing drawings requires complex steps. Furthermore, existing SWMM models suffer from slow computation speeds due to their use of full-network simulation (or optimization from downstream to upstream). Moreover, current single-objective optimization methods based on SWMM models primarily optimize drainage capacity and simple pipe diameter-based construction costs.

[0004] Further optimization of existing technologies has a very singular design objective, and the design results often suffer from serious defects in one aspect due to neglecting others. It is also unable to provide design solutions for the comprehensive design objectives required by different urban environments. When designing pipeline networks, different cities have different natural and economic conditions, and the design objectives that need to be emphasized are different. It is necessary to comprehensively consider various planning objectives such as cost, maximum flooding time, flooding water level, flooding economic loss value, and failure impact range.

[0005] However, SWMM cannot automatically design pipelines during simulation, and it also cannot optimize pipeline design based on multiple optimization objectives. Summary of the Invention

[0006] This invention provides a method and apparatus for designing drainage area pipelines to solve the problem of not being able to simultaneously optimize multiple design requirements in pipeline design.

[0007] Firstly, this application provides a method for designing drainage area pipes, including:

[0008] Several regional design schemes are generated; each regional design scheme includes the pipe parameters of all pipes, and the pipe parameters in each regional design scheme meet the constraints. The pipe parameters are multiple factors that need to be designed for each section of the drainage pipe.

[0009] According to the non-dominated sorting genetic algorithm, the several region design schemes are iteratively updated; until a region design scheme reaches the optimization standard or the number of iterations reaches a preset threshold, all region design schemes of the first dominant set are output.

[0010] The first dominance set is the set of regional design schemes that are not dominated by other regional design schemes. In each iteration, a new regional design scheme is generated based on the regional design scheme, the fitness value of the new regional design scheme is calculated based on the fitness value function, and the dominance relationship between the new regional design scheme and other regional design schemes and the crowding coefficient of the new regional design scheme are calculated based on the fitness value of the new regional design scheme. All regional design schemes are sorted according to the dominance relationship and the crowding coefficient, and the regional design schemes are updated according to the sorting results.

[0011] Based on the preset pipeline parameter weighting criteria, the final drainage area design scheme is selected from all area design schemes in the first dominant set.

[0012] This method uses a non-dominated sorting genetic algorithm to iteratively update the regional design schemes without first converting them to a Swing Model (SWMM) model, thus eliminating the speed reduction caused by the SWMM model. Furthermore, the regional design schemes include multiple factors that need to be designed for each section of the drainage pipeline, and these factors can be updated simultaneously during iterative updates. By comprehensively analyzing the importance of the design factors, the important design factors in the drainage pipeline design are obtained as pipeline parameters. Multiple design schemes are generated during the iterative update process. By setting multiple regional design schemes, the update and iteration method of the regional design schemes in the solution space is planned, increasing the number of regional design schemes to reduce computational load, while simultaneously optimizing all pipeline parameters to obtain the final drainage regional design scheme.

[0013] Furthermore, the step of calculating the fitness value of the new regional design scheme based on the fitness value function also includes:

[0014] When an erroneous region design scheme exists, change the corresponding fitness function that calculates the fitness value of the erroneous region design scheme.

[0015] Among them, the error region design scheme is a new region design scheme where there are pipeline parameters that do not meet the constraints.

[0016] In this way, when pipeline parameters exceed constraints during the iteration process, changing the corresponding fitness function can not only evaluate the degree to which the pipeline parameters exceed the constraints, but also reduce the computational load and speed up the iteration by replacing the complex fitness function with a simpler one. Furthermore, the new fitness function facilitates the subsequent ranking process of all region design schemes based on the calculation results within the fitness function.

[0017] Furthermore, the pipeline parameters are multiple factors that need to be designed for each section of the drainage pipeline, specifically:

[0018] The three factors that need to be designed for each section of the drainage pipeline are obtained as three pipeline parameters.

[0019] The three pipeline parameters are the starting burial depth, ending burial depth, and pipe diameter of each pipeline segment.

[0020] By selecting the most universal and representative factors as pipeline parameters, such as the starting point burial depth, the ending point burial depth, and the pipe diameter, this application can be made applicable to most urban drainage planning scenarios, thus expanding its scope of application.

[0021] Furthermore, the constraints are specifically as follows:

[0022] The constraints of all pipeline parameters are determined based on the topography and urban planning data of the area to be designed and the pipeline design specifications.

[0023] The constraints on the three pipeline parameters are the slope constraint and the upstream and downstream constraint of the pipeline segment.

[0024] The slope constraints for each section of the pipeline are determined based on the minimum and maximum slopes specified in urban planning data and pipeline design specifications.

[0025] Based on the constraints of burial depth and pipe diameter between upstream and downstream pipes in the pipeline design specifications, determine the upstream and downstream constraints for each pipeline segment.

[0026] This approach, by determining constraints based on the topography of the design area, urban planning data, and pipeline design specifications, allows for adjustments to be made according to urban planning objectives, resulting in specific constraints that conform to urban planning principles. Furthermore, by imposing slope constraints and upstream / downstream constraints on the three pipeline parameters, the influence of the relationships between different parameters on the same pipeline on pipeline design is demonstrated.

[0027] Furthermore, the determination of slope constraints for each pipeline segment based on minimum and maximum slopes in urban planning data and pipeline design specifications specifically involves:

[0028] g1(x)=(x k -x j) / LI max ,

[0029] g2(x)=I min -(x k -x j ) / L;

[0030] Where g1(x) is the difference between the slope value and the maximum slope in the slope constraint of each pipe segment, and g2(x) is the difference between the slope value and the minimum slope in the slope constraint of each pipe segment. k For the starting depth in each section of the pipeline, x j Let L be the burial depth of the endpoint in each pipe segment, and I be the length of each pipe segment. min and I max Based on the minimum and maximum slopes specified in urban planning data and pipeline design specifications;

[0031] If the result of calculating g1(x) or g2(x) based on the pipeline parameters is greater than 0, it is determined that the pipeline parameters exceed the constraint conditions.

[0032] Furthermore, based on the constraints of burial depth and pipe diameter between upstream and downstream pipes in the pipeline design specifications, the upstream and downstream constraints of each pipeline segment are determined, specifically as follows:

[0033] g3(x)=x 上游j -x 下游k ,

[0034] g4(x)=x 上游m -x 下游m ;

[0035] Where g3(x) is the starting burial depth of the upstream pipeline of each pipeline segment minus the ending burial depth of the downstream pipeline of each pipeline segment; g4(x) is the pipe diameter of the upstream pipeline of each pipeline segment minus the pipe diameter of the downstream pipeline of each pipeline segment; x 上游j x represents the burial depth of the upstream pipeline for each pipeline. 下游k x represents the burial depth of the downstream end point of each pipeline. 上游m Let x be the diameter of the upstream pipe of each pipe. 下游m For each pipeline, the diameter of the downstream pipeline is specified.

[0036] If the result of g3(x) or g4(x) calculated based on the pipeline parameters is greater than 0, it is determined that the pipeline parameters exceed the constraint conditions.

[0037] Furthermore, the calculation of the fitness value of the new regional design scheme based on the fitness value function specifically involves:

[0038] The fitness functions are: maximum water accumulation time, maximum pipeline burial depth, and maximum pipeline diameter;

[0039] The maximum water accumulation time is the maximum value among all water accumulation times in the regional design scheme obtained by converting the regional design scheme into an SWMM model and calculating the SWMM model.

[0040] The maximum burial depth of the pipeline is the maximum value among the end-point burial depths of all pipelines in the regional design scheme.

[0041] The maximum pipe diameter is the maximum value among all pipe diameters in the obtained regional design scheme.

[0042] This approach transforms the regional design scheme into an SWMM model only when calculating the fitness values, rather than incorporating the entire design process into the SWMM model from the outset. This reduces the involvement of the SWMM model in the iteration process, thus addressing the issue of slow reduction speed caused by the SWMM model. Furthermore, by setting two fitness functions—maximum burial depth and maximum pipe diameter—selecting the design scheme with smaller burial depth and pipe diameter while ensuring that the water accumulation time is within allowable limits can reduce design costs without compromising drainage effectiveness.

[0043] Furthermore, the change in the corresponding fitness function for calculating the fitness value of the error region design scheme is specifically as follows:

[0044] Change the maximum water accumulation time in the fitness function to the degree of exceeding the constraint;

[0045] The degree of exceeding the constraint is the sum of the values ​​of all pipe parameters exceeding the constraint in the erroneous area design scheme multiplied by a specific multiple, plus a preset penalty coefficient.

[0046] This approach modifies the fitness function when constraints are exceeded, avoiding a direct reduction in the number of regional design schemes. This prevents information loss and avoids conversion to an SWMM model, reducing computational intensity and increasing iteration speed. Furthermore, setting the constraint exceedance level to the sum of all pipe parameters exceeding constraints in the erroneous regional design scheme multiplied by a specific factor, plus a preset penalty coefficient, reflects the degree of error in the erroneous regional design scheme without affecting the subsequent ranking of regional design schemes.

[0047] Furthermore, the step of selecting the final drainage area design scheme from all area design schemes in the first dominant set according to the preset pipeline parameter weighting standard specifically involves:

[0048] All regional design schemes in the first dominant set are sorted according to the pipeline parameter weighting criteria.

[0049] The design scheme for the area ranked first is the final design scheme for the drainage area.

[0050] This method uses a non-dominated sorting genetic algorithm to iteratively update the regional design schemes without first converting them to a Swing Model (SWMM) model, thus eliminating the speed reduction caused by the SWMM model. Furthermore, the regional design schemes include multiple factors that need to be designed for each section of the drainage pipeline, and these factors can be updated simultaneously during iterative updates. By comprehensively analyzing the importance of the design factors, the important design factors in the drainage pipeline design are obtained as pipeline parameters. Multiple design schemes are generated during the iterative update process. By setting multiple regional design schemes, the update and iteration method of the regional design schemes in the solution space is planned, increasing the number of regional design schemes to reduce computational load, while simultaneously optimizing all pipeline parameters to obtain the final drainage regional design scheme.

[0051] Secondly, this application provides a drainage area pipeline design device, including: an area design scheme generation module, a genetic algorithm module, and a design scheme selection module;

[0052] The regional design scheme generation module is used to generate several regional design schemes; each regional design scheme includes the pipe parameters of all pipes, and the pipe parameters in each regional design scheme meet the constraints. The pipe parameters are multiple factors that need to be designed for each section of the drainage pipe in the design.

[0053] The genetic algorithm module is used to iteratively update the several region design schemes according to the non-dominated sorting genetic algorithm; until a region design scheme reaches the optimization standard or the number of iterations reaches a preset threshold, the module outputs all region design schemes of the first dominant set.

[0054] Among them, the first dominating set is the set of regional design schemes that are not dominated by other regional design schemes among all regional design schemes;

[0055] In each iteration, a new regional design scheme is generated based on the regional design scheme. The fitness value of the new regional design scheme is calculated based on the fitness value function. The dominance relationship between the new regional design scheme and other regional design schemes and the crowding coefficient of the new regional design scheme are calculated based on the fitness value of the new regional design scheme. All regional design schemes are sorted according to the dominance relationship and the crowding coefficient. The regional design scheme is then updated based on the sorting results.

[0056] The design scheme selection module is used to select the final drainage area design scheme from all area design schemes in the first dominant set according to the preset pipeline parameter weighting standard.

[0057] Furthermore, the genetic algorithm module includes an fitness value function modification unit;

[0058] The fitness value function changing unit is used to change the corresponding fitness value function for calculating the fitness value of the erroneous region design scheme when there is an erroneous region design scheme.

[0059] Among them, the error region design scheme is a new region design scheme where there are pipeline parameters that do not meet the constraints.

[0060] Furthermore, the regional design scheme generation module includes: a pipeline parameter setting unit;

[0061] The pipeline parameter setting unit is used to obtain three factors that need to be designed for each section of the drainage pipeline as three pipeline parameters.

[0062] The three pipeline parameters are the starting burial depth, ending burial depth, and pipe diameter of each pipeline segment.

[0063] Furthermore, the regional design scheme generation module includes: a constraint condition acquisition unit, a slope constraint determination unit, and an upstream and downstream constraint determination unit;

[0064] The constraint condition acquisition unit is used to determine the constraint conditions of all pipeline parameters based on the topography and urban planning data of the area to be designed and the pipeline design specifications.

[0065] The constraints on the three pipeline parameters are the slope constraint and the upstream and downstream constraint of the pipeline segment.

[0066] The slope constraint unit is used to determine the slope constraint of each pipeline segment based on the minimum and maximum slopes in urban planning data and pipeline design specifications.

[0067] The upstream and downstream constraint unit is used to determine the upstream and downstream constraints of each pipeline segment based on the constraints of burial depth and pipe diameter between upstream and downstream pipelines in the pipeline design specifications.

[0068] Furthermore, the slope constraint unit includes: a slope constraint value calculation unit and a slope constraint determination unit;

[0069] The slope constraint value calculation unit is used to calculate the slope constraint for each section of the pipeline, specifically:

[0070] g1(x)=(x k -x j ) / LI max ,

[0071] g2(x)=I min -(x k -x j ) / L;

[0072] Where g1(x) is the difference between the slope value and the maximum slope in the slope constraint of each pipe segment, and g2(x) is the difference between the slope value and the minimum slope in the slope constraint of each pipe segment. k For the starting depth in each section of the pipeline, x j Let L be the burial depth of the endpoint in each pipe segment, and I be the length of each pipe segment. min and I max Based on the minimum and maximum slopes specified in urban planning data and pipeline design specifications;

[0073] The slope constraint determination unit is used to determine that the pipeline parameters exceed the constraint conditions when the result of calculating g1(x) or g2(x) based on the pipeline parameters is greater than 0.

[0074] Furthermore, the upstream and downstream constraint unit includes: an upstream and downstream constraint value calculation unit and an upstream and downstream constraint determination unit;

[0075] The upstream and downstream constraint value calculation unit is used to calculate the upstream and downstream constraints of each pipeline segment, specifically:

[0076] g3(x)=x 上游 jx 下游k ,

[0077] g4(x)=x 上游m -x 下游m ;

[0078] Where g3(x) is the starting burial depth of the upstream pipeline of each pipeline segment minus the ending burial depth of the downstream pipeline of each pipeline segment; g4(x) is the pipe diameter of the upstream pipeline of each pipeline segment minus the pipe diameter of the downstream pipeline of each pipeline segment; x 上游j x represents the burial depth of the upstream pipeline for each pipeline. 下游k x represents the burial depth of the downstream end point of each pipeline. 上游m Let x be the diameter of the upstream pipe of each pipe. 下游m For each pipeline, the diameter of the downstream pipeline is specified.

[0079] The upstream and downstream constraint determination unit is used to determine that the pipeline parameters exceed the constraint conditions when the result of g3(x) or g4(x) calculated based on the pipeline parameters is greater than 0.

[0080] Furthermore, the genetic algorithm module includes: a fitness function determination unit, a maximum water accumulation time calculation unit, a pipeline maximum burial depth calculation unit, and a pipeline maximum diameter calculation unit;

[0081] The fitness function determination unit is used to determine the fitness functions as follows: maximum water accumulation time, maximum pipeline burial depth, and maximum pipeline diameter.

[0082] The maximum water accumulation time calculation unit is used to determine the maximum water accumulation time as the maximum value among all water accumulation times in the regional design scheme obtained by converting the regional design scheme into an SWMM model and calculating the SWMM model.

[0083] The pipeline maximum burial depth calculation unit is used to determine the pipeline maximum burial depth as the maximum value among the endpoint burial depths of all pipelines in the regional design scheme;

[0084] The maximum pipe diameter calculation unit calculates the maximum pipe diameter as the maximum value among all pipe diameters in the regional design scheme.

[0085] Furthermore, the adaptive value function change unit includes: a change confirmation unit;

[0086] The change confirmation unit is used to change the maximum water accumulation time in the adaptive value function to exceed the constraint level;

[0087] The degree of exceeding the constraint is the sum of the values ​​of all pipe parameters exceeding the constraint in the erroneous area design scheme multiplied by a specific multiple, plus a preset penalty coefficient.

[0088] Furthermore, the design scheme selection module includes: a regional design scheme sorting unit and a final design scheme determination unit;

[0089] The regional design scheme sorting unit is used to sort all regional design schemes in the first dominant set according to the pipeline parameter weight standard;

[0090] The final design scheme determination unit is used to obtain the top-ranked regional design scheme as the final drainage regional design scheme.

[0091] This method uses a non-dominated sorting genetic algorithm to iteratively update the regional design schemes without first converting them to a Swing Model (SWMM) model. This eliminates the factor that reduces the iteration speed due to the SWMM model. The regional design schemes are only converted to the SWMM model when calculating the fitness value, rather than being included in the entire design process from the beginning. This reduces the involvement of the SWMM model in the iteration process, thus solving the problem of slow reduction speed caused by the SWMM model. Furthermore, setting two fitness functions—maximum burial depth and maximum pipe diameter—allows for selecting the design scheme with smaller burial depth and pipe diameter while ensuring that the water accumulation time is within allowable limits. This reduces design costs without compromising drainage efficiency.

[0092] The further regional design scheme includes multiple factors that need to be designed for each section of the drainage pipeline. Selecting the starting and ending burial depths and pipe diameter as pipeline parameters expands the applicability of this application to most urban drainage planning scenarios. This allows for a comprehensive analysis of the importance of the factors to be planned and designed. Multiple design schemes are generated during iterative updates. By setting multiple regional design schemes and planning the update and iteration methods of the regional design schemes in the solution space, the number of regional design schemes is increased to reduce the computational load, while simultaneously optimizing all pipeline parameters to obtain the final drainage regional design scheme. Attached Figure Description

[0093] Figure 1 : A schematic flowchart of an embodiment of a drainage area pipeline design method provided by the present invention;

[0094] Figure 2 : A modular structure diagram of an embodiment of a drainage area pipeline design device provided by the present invention;

[0095] Figure 3 : A partial module structure diagram of the genetic algorithm module of an embodiment of a drainage area pipeline design device provided by the present invention;

[0096] Figure 4 This is a partial module structure diagram of the area design scheme generation module of an embodiment of a drainage area pipeline design device provided by the present invention.

[0097] Figure 5 This is a partial structural diagram of the area design scheme generation module of an embodiment of a drainage area pipeline design device provided by the present invention.

[0098] Figure 6 : A partial structural diagram of the genetic algorithm module of an embodiment of a drainage area pipeline design device provided by the present invention;

[0099] Figure 7 This is a partial module structure diagram of the design scheme selection module of an embodiment of a drainage area pipeline design device provided by the present invention. Detailed Implementation

[0100] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0101] Example 1

[0102] Please refer to Figure 1 The present invention provides a drainage area pipeline design method, comprising steps S1 to S3, the specific steps of which are as follows:

[0103] Step S1: Generate several regional design schemes; each regional design scheme includes all pipe parameters, and the pipe parameters in each regional design scheme meet the constraints. The pipe parameters are multiple factors that need to be designed for each section of the drainage pipe.

[0104] Step S2: Iteratively update the several region design schemes according to the non-dominated sorting genetic algorithm; until a region design scheme reaches the optimization standard or the number of iterations reaches the preset threshold, output all region design schemes of the first dominant set;

[0105] In one embodiment, "until the optimization criterion is met among all regional design schemes" means that the regional design scheme that appears to be a solution in the Pareto front solution set appears among all regional design schemes.

[0106] The first dominance set is the set of regional design schemes that are not dominated by other regional design schemes. In each iteration, a new regional design scheme is generated based on the regional design scheme, the fitness value of the new regional design scheme is calculated based on the fitness value function, and the dominance relationship between the new regional design scheme and other regional design schemes and the crowding coefficient of the new regional design scheme are calculated based on the fitness value of the new regional design scheme. All regional design schemes are sorted according to the dominance relationship and the crowding coefficient, and the regional design schemes are updated according to the sorting results.

[0107] Step S3: Select the final drainage area design scheme from all area design schemes in the first dominant set according to the preset pipeline parameter weighting standard.

[0108] This method uses a non-dominated sorting genetic algorithm to iteratively update the regional design schemes without first converting them to a Swing Model (SWMM) model, thus eliminating the speed reduction caused by the SWMM model. Furthermore, the regional design schemes include multiple factors that need to be designed for each section of the drainage pipeline, and these factors can be updated simultaneously during iterative updates. By comprehensively analyzing the importance of the design factors, the important design factors in the drainage pipeline design are obtained as pipeline parameters. Multiple design schemes are generated during the iterative update process. By setting multiple regional design schemes, the update and iteration method of the regional design schemes in the solution space is planned, increasing the number of regional design schemes to reduce computational load, while simultaneously optimizing all pipeline parameters to obtain the final drainage regional design scheme.

[0109] Furthermore, the step of calculating the fitness value of the new regional design scheme based on the fitness value function also includes:

[0110] When an erroneous region design scheme exists, change the corresponding fitness function that calculates the fitness value of the erroneous region design scheme.

[0111] Among them, the error region design scheme is a new region design scheme where there are pipeline parameters that do not meet the constraints.

[0112] In this way, when pipeline parameters exceed constraints during the iteration process, changing the corresponding fitness function can not only evaluate the degree to which the pipeline parameters exceed the constraints, but also reduce the computational load and speed up the iteration by replacing the complex fitness function with a simpler one. Furthermore, the new fitness function facilitates the subsequent ranking process of all region design schemes based on the calculation results within the fitness function.

[0113] Furthermore, the pipeline parameters are multiple factors that need to be designed for each section of the drainage pipeline, specifically:

[0114] The three factors that need to be designed for each section of the drainage pipeline are obtained as three pipeline parameters.

[0115] The three pipeline parameters are the starting burial depth, ending burial depth, and pipe diameter of each pipeline segment.

[0116] By selecting the most universal and representative factors as pipeline parameters, such as the starting point burial depth, the ending point burial depth, and the pipe diameter, this application can be made applicable to most urban drainage planning scenarios, thus expanding its scope of application.

[0117] Furthermore, the constraints are specifically as follows:

[0118] The constraints of all pipeline parameters are determined based on the topography and urban planning data of the area to be designed and the pipeline design specifications.

[0119] The constraints on the three pipeline parameters are the slope constraint and the upstream and downstream constraint of the pipeline segment.

[0120] The slope constraints for each section of the pipeline are determined based on the minimum and maximum slopes specified in urban planning data and pipeline design specifications.

[0121] Based on the constraints of burial depth and pipe diameter between upstream and downstream pipes in the pipeline design specifications, determine the upstream and downstream constraints for each pipeline segment.

[0122] This approach, by determining constraints based on the topography of the design area, urban planning data, and pipeline design specifications, allows for adjustments to be made according to urban planning objectives, resulting in specific constraints that conform to urban planning principles. Furthermore, by imposing slope constraints and upstream / downstream constraints on the three pipeline parameters, the influence of the relationships between different parameters on the same pipeline on pipeline design is demonstrated.

[0123] Furthermore, the determination of slope constraints for each pipeline segment based on minimum and maximum slopes in urban planning data and pipeline design specifications specifically involves:

[0124] g1(x)=(x k -x j ) / LI max ,

[0125] g2(x)=I min -(x k -x j ) / L;

[0126] Where g1(x) is the difference between the slope value and the maximum slope in the slope constraint of each pipe segment, and g2(x) is the difference between the slope value and the minimum slope in the slope constraint of each pipe segment. k For the starting depth in each section of the pipeline, x j Let L be the burial depth of the endpoint in each pipe segment, and I be the length of each pipe segment. min and I max Based on the minimum and maximum slopes specified in urban planning data and pipeline design specifications;

[0127] If the result of calculating g1(x) or g2(x) based on the pipeline parameters is greater than 0, it is determined that the pipeline parameters exceed the constraint conditions.

[0128] Furthermore, based on the constraints of burial depth and pipe diameter between upstream and downstream pipes in the pipeline design specifications, the upstream and downstream constraints of each pipeline segment are determined, specifically as follows:

[0129] g3(x)=x 上游j -x 下游k ,

[0130] g4(x)=x 上游m -x 下游m ;

[0131] Where g3(x) is the starting burial depth of the upstream pipeline of each pipeline segment minus the ending burial depth of the downstream pipeline of each pipeline segment; g4(x) is the pipe diameter of the upstream pipeline of each pipeline segment minus the pipe diameter of the downstream pipeline of each pipeline segment; x 上游j x represents the burial depth of the upstream pipeline for each pipeline. 下游k x represents the burial depth of the downstream end point of each pipeline.上游m Let x be the diameter of the upstream pipe of each pipe. 下游m For each pipeline, the diameter of the downstream pipeline is specified.

[0132] If the result of g3(x) or g4(x) calculated based on the pipeline parameters is greater than 0, it is determined that the pipeline parameters exceed the constraint conditions.

[0133] In the specific implementation, g3(x) can mean that the slope of the upstream pipeline must not be greater than the slope of the downstream pipeline, without limiting whether the upstream and downstream pipelines are connected to each other.

[0134] Similarly, g4(x) can mean that the diameter of the upstream pipe must not be greater than the diameter of the downstream pipe, without limiting whether the upstream and downstream pipes are connected to each other.

[0135] Furthermore, the calculation of the fitness value of the new regional design scheme based on the fitness value function specifically involves:

[0136] The fitness functions are: maximum water accumulation time, maximum pipeline burial depth, and maximum pipeline diameter;

[0137] The maximum water accumulation time is the maximum value among all water accumulation times in the regional design scheme obtained by converting the regional design scheme into an SWMM model and calculating the SWMM model.

[0138] The maximum burial depth of the pipeline is the maximum value among the end-point burial depths of all pipelines in the regional design scheme.

[0139] The maximum pipe diameter is the maximum value among all pipe diameters in the obtained regional design scheme.

[0140] This approach transforms the regional design scheme into an SWMM model only when calculating the fitness values, rather than incorporating the entire design process into the SWMM model from the outset. This reduces the involvement of the SWMM model in the iteration process, thus addressing the issue of slow reduction speed caused by the SWMM model. Furthermore, by setting two fitness functions—maximum burial depth and maximum pipe diameter—selecting the design scheme with smaller burial depth and pipe diameter while ensuring that the water accumulation time is within allowable limits can reduce design costs without compromising drainage effectiveness.

[0141] Furthermore, the change in the corresponding fitness function for calculating the fitness value of the error region design scheme is specifically as follows:

[0142] Change the maximum water accumulation time in the fitness function to the degree of exceeding the constraint;

[0143] The degree of exceeding the constraint is the sum of the values ​​of all pipe parameters exceeding the constraint in the erroneous area design scheme multiplied by a specific multiple, plus a preset penalty coefficient.

[0144] In one specific embodiment, the formula for calculating the degree of exceeding the constraint is as follows:

[0145]

[0146] Where g i (x) represents the value exceeding the constraint, and i represents the number of pipeline parameters exceeding the constraint.

[0147] This approach modifies the fitness function when constraints are exceeded, avoiding a direct reduction in the number of regional design schemes. This prevents information loss and avoids conversion to an SWMM model, reducing computational intensity and increasing iteration speed. Furthermore, setting the constraint exceedance level to the sum of all pipe parameters exceeding constraints in the erroneous regional design scheme multiplied by a specific factor, plus a preset penalty coefficient, reflects the degree of error in the erroneous regional design scheme without affecting the subsequent ranking of regional design schemes.

[0148] Furthermore, the step of selecting the final drainage area design scheme from all area design schemes in the first dominant set according to the preset pipeline parameter weighting standard specifically involves:

[0149] All regional design schemes in the first dominant set are sorted according to the pipeline parameter weighting criteria.

[0150] The design scheme for the area ranked first is the final design scheme for the drainage area.

[0151] In the specific implementation, after normalizing the range of each target value, the user assigns a weight value to each target to form a weight standard. The solution represented by the point closest to the weight standard is calculated, and the output is the user's preferred design solution.

[0152] This method uses a non-dominated sorting genetic algorithm to iteratively update the regional design schemes without first converting them to a Swing Model (SWMM) model, thus eliminating the speed reduction caused by the SWMM model. Furthermore, the regional design schemes include multiple factors that need to be designed for each section of the drainage pipeline, and these factors can be updated simultaneously during iterative updates. By comprehensively analyzing the importance of the design factors, the important design factors in the drainage pipeline design are obtained as pipeline parameters. Multiple design schemes are generated during the iterative update process. By setting multiple regional design schemes, the update and iteration method of the regional design schemes in the solution space is planned, increasing the number of regional design schemes to reduce computational load, while simultaneously optimizing all pipeline parameters to obtain the final drainage regional design scheme.

[0153] Example 2

[0154] Please refer to Figure 2 This is a modular structure diagram of an embodiment of a drainage area pipeline design device provided by the present invention.

[0155] A drainage area pipeline design device includes: an area design scheme generation module 210, a genetic algorithm module 220, and a design scheme selection module 230;

[0156] The regional design scheme generation module 210 is used to generate several regional design schemes; wherein, each regional design scheme includes the pipe parameters of all pipes, and the pipe parameters in each regional design scheme meet the constraints, and the pipe parameters are multiple factors that need to be designed for each section of the drainage pipe in the design.

[0157] The genetic algorithm module 220 is used to iteratively update the plurality of region design schemes according to the non-dominated sorting genetic algorithm; until a region design scheme reaches the optimization standard or the number of iterations reaches a preset threshold, the module outputs all region design schemes of the first dominant set.

[0158] Among them, the first dominating set is the set of regional design schemes that are not dominated by other regional design schemes among all regional design schemes;

[0159] In each iteration, a new regional design scheme is generated based on the regional design scheme. The fitness value of the new regional design scheme is calculated based on the fitness value function. The dominance relationship between the new regional design scheme and other regional design schemes and the crowding coefficient of the new regional design scheme are calculated based on the fitness value of the new regional design scheme. All regional design schemes are sorted according to the dominance relationship and the crowding coefficient. The regional design scheme is then updated based on the sorting results.

[0160] The design scheme selection module 230 is used to select the final drainage area design scheme from all area design schemes of the first dominant set according to the preset pipeline parameter weight standard.

[0161] Furthermore, such as Figure 3 The genetic algorithm module 220 includes an fitness value function modification unit 221;

[0162] The fitness function changing unit 221 is used to change the corresponding fitness function for calculating the fitness value of the erroneous region design scheme when there is an erroneous region design scheme.

[0163] Among them, the error region design scheme is a new region design scheme where there are pipeline parameters that do not meet the constraints.

[0164] Furthermore, such as Figure 4 The regional design scheme generation module 210 includes: a pipeline parameter setting unit 211;

[0165] The pipeline parameter setting unit 211 is used to obtain three factors that need to be designed for each section of the drainage pipeline as three pipeline parameters.

[0166] The three pipeline parameters are the starting burial depth, ending burial depth, and pipe diameter of each pipeline segment.

[0167] Furthermore, such as Figure 5 The regional design scheme generation module 210 includes: a constraint condition acquisition unit 212, a slope constraint unit 213, and an upstream and downstream constraint unit 214;

[0168] The constraint condition acquisition unit 212 is used to determine the constraint conditions of all pipeline parameters based on the topography and urban planning data of the area to be designed and the pipeline design specifications.

[0169] The constraints on the three pipeline parameters are the slope constraint and the upstream and downstream constraint of the pipeline segment.

[0170] The slope constraint unit 213 is used to determine the slope constraint of each pipeline segment based on the minimum and maximum slopes in urban planning data and pipeline design specifications.

[0171] The upstream and downstream constraint unit 214 is used to determine the upstream and downstream constraints of each pipeline segment according to the constraints on the burial depth and pipe diameter between upstream and downstream pipelines in the pipeline design specifications.

[0172] Furthermore, the slope constraint unit 213 includes: a slope constraint value calculation unit 2131 and a slope constraint determination unit 2132;

[0173] The slope constraint value calculation unit 2131 is used to calculate the slope constraint of each pipe segment, specifically:

[0174] g1(x)=(x k -x j ) / LI max ,

[0175] g2(x)=I min -(x k -x j ) / L;

[0176] Where g1(x) is the difference between the slope value and the maximum slope in the slope constraint of each pipe segment, and g2(x) is the difference between the slope value and the minimum slope in the slope constraint of each pipe segment. k For the starting depth in each section of the pipeline, x j Let L be the burial depth of the endpoint in each pipe segment, and I be the length of each pipe segment. min and I max Based on the minimum and maximum slopes specified in urban planning data and pipeline design specifications;

[0177] The slope constraint determination unit 2132 is used to determine that the pipeline parameters exceed the constraint conditions when the result of calculating g1(x) or g2(x) based on the pipeline parameters is greater than 0.

[0178] Furthermore, the upstream and downstream constraint unit 214 includes: an upstream and downstream constraint value calculation unit 2141 and an upstream and downstream constraint determination unit 2142;

[0179] The upstream and downstream constraint value calculation unit 2141 is used to calculate the upstream and downstream constraints of each pipeline segment, specifically:

[0180] g3(x)=x 上游j -x 下游k ,

[0181] g4(x)=x 上游m -x 下游m ;

[0182] Where g3(x) is the starting burial depth of the upstream pipeline of each pipeline segment minus the ending burial depth of the downstream pipeline of each pipeline segment; g4(x) is the pipe diameter of the upstream pipeline of each pipeline segment minus the pipe diameter of the downstream pipeline of each pipeline segment; x 上游j x represents the burial depth of the upstream pipeline for each pipeline. 下游k x represents the burial depth of the downstream end point of each pipeline. 上游m Let x be the diameter of the upstream pipe of each pipe. 下游m For each pipeline, the diameter of the downstream pipeline is specified.

[0183] The upstream and downstream constraint determination unit 2142 is used to determine that the pipeline parameters exceed the constraint conditions when the result of calculating g3(x) or g4(x) based on the pipeline parameters is greater than 0.

[0184] Furthermore, such as Figure 6 The genetic algorithm module 220 includes: a fitness function determination unit 222, a maximum water accumulation time calculation unit 223, a pipeline maximum burial depth calculation unit 224, and a pipeline maximum diameter calculation unit 225;

[0185] The fitness function determination unit 222 is used to determine the fitness functions as follows: maximum water accumulation time, maximum pipeline burial depth, and maximum pipeline diameter;

[0186] The maximum water accumulation time calculation unit 223 is used to determine the maximum water accumulation time as the maximum value among all regional water accumulation times in the regional design scheme obtained by converting the regional design scheme into an SWMM model and calculating the SWMM model.

[0187] The pipeline maximum burial depth calculation unit 224 is used to determine the pipeline maximum burial depth as the maximum value among the endpoint burial depths of all pipelines in the regional design scheme;

[0188] The maximum pipe diameter calculation unit 225 calculates the maximum pipe diameter as the maximum value among all pipe diameters in the regional design scheme.

[0189] Furthermore, the adaptive value function change unit 222 includes: a change confirmation unit 2221;

[0190] The change confirmation unit 2221 is used to change the maximum water accumulation time in the fitness value function to exceed the constraint level;

[0191] The degree of exceeding the constraint is the sum of the values ​​of all pipe parameters exceeding the constraint in the erroneous area design scheme multiplied by a specific multiple, plus a preset penalty coefficient.

[0192] Furthermore, such as Figure 7 The design scheme selection module 230 includes: a regional design scheme sorting unit 231 and a final design scheme determination unit 232;

[0193] The regional design scheme sorting unit 231 is used to sort all regional design schemes in the first dominant set according to the pipeline parameter weight standard;

[0194] The final design scheme determination unit 232 is used to obtain the first-ranked regional design scheme as the final drainage regional design scheme.

[0195] This method uses a non-dominated sorting genetic algorithm to iteratively update the regional design schemes without first converting them to a Swing Model (SWMM) model. This eliminates the factor that reduces the iteration speed due to the SWMM model. The regional design schemes are only converted to the SWMM model when calculating the fitness value, rather than being included in the entire design process from the beginning. This reduces the involvement of the SWMM model in the iteration process, thus solving the problem of slow reduction speed caused by the SWMM model. Furthermore, setting two fitness functions—maximum burial depth and maximum pipe diameter—allows for selecting the design scheme with smaller burial depth and pipe diameter while ensuring that the water accumulation time is within allowable limits. This reduces design costs without compromising drainage efficiency.

[0196] The further regional design scheme includes multiple factors that need to be designed for each section of the drainage pipeline. Selecting the starting and ending burial depths and pipe diameter as pipeline parameters expands the applicability of this application to most urban drainage planning scenarios. This allows for a comprehensive analysis of the importance of the factors to be planned and designed. Multiple design schemes are generated during iterative updates. By setting multiple regional design schemes and planning the update and iteration methods of the regional design schemes in the solution space, the number of regional design schemes is increased to reduce the computational load, while simultaneously optimizing all pipeline parameters to obtain the final drainage regional design scheme.

[0197] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for designing drainage area pipes, characterized in that, include: Several regional design schemes are generated; each regional design scheme includes the pipe parameters of all pipes, and the pipe parameters in each regional design scheme meet the constraints. The pipe parameters are multiple factors that need to be designed for each section of the drainage pipe. According to the non-dominated sorting genetic algorithm, the several region design schemes are iteratively updated; until a region design scheme reaches the optimization standard or the number of iterations reaches a preset threshold, all region design schemes of the first dominant set are output. The first dominance set is the set of all regional design schemes that are not dominated by other regional design schemes. In each iteration, a new regional design scheme is generated based on the existing regional design schemes. The fitness value of the new regional design scheme is calculated using the fitness function. Furthermore, the dominance relationship between the new regional design scheme and other regional design schemes, as well as the congestion coefficient of the new regional design scheme, are calculated based on the fitness value. All regional design schemes are then sorted according to their dominance relationship and congestion coefficient, and the regional design schemes are updated based on the sorting results. The calculation of the fitness value of the new regional design scheme using the fitness function also includes: when an erroneous regional design scheme exists, changing the corresponding fitness function used to calculate the fitness value of the erroneous regional design scheme. The number; wherein, the erroneous region design scheme is a new region design scheme with pipeline parameters that do not meet the constraints; the fitness functions are: maximum water accumulation time, maximum pipeline burial depth, and maximum pipeline diameter; the maximum water accumulation time is the maximum value among all regional water accumulation times in the region design scheme calculated by converting the region design scheme into an SWMM model; the change of the corresponding fitness function for calculating the fitness value of the erroneous region design scheme specifically involves: changing the maximum water accumulation time in the fitness function to the degree of exceeding the constraints; wherein, the degree of exceeding the constraints is the sum of the excess values ​​of all pipeline parameters in the erroneous region design scheme that exceed the constraints multiplied by a specific multiple plus a preset penalty coefficient; Based on the preset pipeline parameter weighting criteria, the final drainage area design scheme is selected from all area design schemes in the first dominant set.

2. The drainage area pipeline design method according to claim 1, characterized in that, The pipeline parameters are multiple factors that need to be designed for each section of drainage pipeline, specifically: The three factors that need to be designed for each section of the drainage pipeline are obtained as three pipeline parameters. The three pipeline parameters are the starting burial depth, ending burial depth, and pipe diameter of each pipeline segment.

3. The drainage area pipeline design method according to claim 2, characterized in that, The constraints are specifically as follows: The constraints of all pipeline parameters are determined based on the topography and urban planning data of the area to be designed and the pipeline design specifications. The constraints on the three pipeline parameters are the slope constraint and the upstream and downstream constraint of the pipeline segment. The slope constraints for each section of the pipeline are determined based on the minimum and maximum slopes specified in urban planning data and pipeline design specifications. Based on the constraints of burial depth and pipe diameter between upstream and downstream pipes in the pipeline design specifications, determine the upstream and downstream constraints for each pipeline segment.

4. The drainage area pipeline design method according to claim 3, characterized in that, The slope constraint for each pipeline segment is determined based on the minimum and maximum slopes specified in urban planning data and pipeline design specifications, specifically as follows: ， ； in, This is the difference between the slope value and the maximum slope in the slope constraint for each pipeline segment. This is the difference between the slope value and the minimum slope in the slope constraint for each pipeline segment. The burial depth of the starting point in each section of the pipeline, The burial depth of the endpoint in each section of the pipeline. The length of each pipe segment, and Based on the minimum and maximum slopes specified in urban planning data and pipeline design specifications; When there is a calculation based on pipeline parameters or When the result is greater than 0, it is determined that the pipeline parameters exceed the constraint conditions.

5. The drainage area pipeline design method according to claim 3, characterized in that, The upstream and downstream constraints of each pipeline segment are determined based on the constraints of burial depth and pipe diameter between upstream and downstream sections in the pipeline design specifications, specifically as follows: ， ； in, Subtract the burial depth of the downstream pipeline from the starting burial depth of the upstream pipeline for each pipeline segment. Subtract the diameter of the downstream pipe from the diameter of the upstream pipe for each pipe segment. The burial depth of the upstream pipeline for each pipeline. The burial depth of the downstream end point of each pipeline. For each pipeline, the diameter of the upstream pipeline is... For each pipeline, the diameter of the downstream pipeline is specified. When there is a calculation based on pipeline parameters or When the result is greater than 0, it is determined that the pipeline parameters exceed the constraint conditions.

6. The drainage area pipeline design method according to claim 2, characterized in that, The calculation of the fitness value of the new regional design scheme based on the fitness value function specifically involves: The maximum burial depth of the pipeline is the maximum value among the end-point burial depths of all pipelines in the regional design scheme. The maximum pipe diameter is the maximum value among all pipe diameters in the obtained regional design scheme.

7. The drainage area pipeline design method according to claim 2, characterized in that, The step of selecting the final drainage area design scheme from all area design schemes in the first dominant set according to the preset pipeline parameter weighting standard is as follows: All regional design schemes in the first dominant set are sorted according to the pipeline parameter weighting criteria. The design scheme for the area ranked first is the final design scheme for the drainage area.

8. A drainage area pipeline design device, characterized in that, include: The module includes a region design scheme generation module, a genetic algorithm module, and a design scheme selection module. The regional design scheme generation module is used to generate several regional design schemes; each regional design scheme includes the pipe parameters of all pipes, and the pipe parameters in each regional design scheme meet the constraints. The pipe parameters are multiple factors that need to be designed for each section of the drainage pipe in the design. The genetic algorithm module is used to iteratively update the several region design schemes according to the non-dominated sorting genetic algorithm; until a region design scheme reaches the optimization standard or the number of iterations reaches a preset threshold, the module outputs all region design schemes of the first dominant set. The first dominance set is the set of regional design schemes that are not dominated by other regional design schemes. In each iteration, a new regional design scheme is generated based on the existing regional design schemes. The fitness value of the new regional design scheme is calculated based on the fitness function. Furthermore, the dominance relationship between the new regional design scheme and other regional design schemes, as well as the congestion coefficient of the new regional design scheme, are calculated based on the fitness value. All regional design schemes are then sorted according to the dominance relationship and congestion coefficient, and the regional design schemes are updated based on the sorting results. The genetic algorithm module includes a fitness function modification unit. This unit is used to change the corresponding fitness function used to calculate the fitness value of an erroneous regional design scheme when an erroneous regional design scheme exists. The erroneous regional design scheme is defined as a pipeline parameter that does not meet the constraints. A new regional design scheme; the genetic algorithm module includes: a fitness function determination unit and a maximum water accumulation time calculation unit; the fitness function determination unit is used to determine the fitness functions as: maximum water accumulation time, maximum pipeline burial depth, and maximum pipeline diameter; the maximum water accumulation time calculation unit is used to determine the maximum water accumulation time as the maximum value among all regional water accumulation times in the regional design scheme obtained by converting the regional design scheme into an SWMM model and calculating the SWMM model; the fitness function modification unit includes: a modification confirmation unit; the modification confirmation unit is used to change the maximum water accumulation time in the fitness function to the degree of exceeding constraints; wherein, the degree of exceeding constraints is the sum of the excess values ​​of all pipeline parameters exceeding the constraints in the erroneous regional design scheme multiplied by a specific multiple plus a preset penalty coefficient; The design scheme selection module is used to select the final drainage area design scheme from all area design schemes in the first dominant set according to the preset pipeline parameter weighting standard.

9. The drainage area pipeline design device according to claim 8, characterized in that, The regional design scheme generation module includes: a pipeline parameter setting unit; The pipeline parameter setting unit is used to obtain three factors that need to be designed for each section of the drainage pipeline as three pipeline parameters. The three pipeline parameters are the starting burial depth, ending burial depth, and pipe diameter of each pipeline segment.

10. The drainage area pipeline design device according to claim 9, characterized in that, The regional design scheme generation module includes: a constraint condition acquisition unit, a slope constraint unit, and an upstream and downstream constraint unit; The constraint condition acquisition unit is used to determine the constraint conditions of all pipeline parameters based on the topography and urban planning data of the area to be designed and the pipeline design specifications. The constraints on the three pipeline parameters are the slope constraint and the upstream and downstream constraint of the pipeline segment. The slope constraint unit is used to determine the slope constraint of each pipeline segment based on the minimum and maximum slopes in urban planning data and pipeline design specifications. The upstream and downstream constraint unit is used to determine the upstream and downstream constraints of each pipeline segment based on the constraints of burial depth and pipe diameter between upstream and downstream pipelines in the pipeline design specifications.

11. The drainage area pipeline design device according to claim 10, characterized in that, The slope constraint unit includes: a slope constraint value calculation unit and a slope constraint determination unit; The slope constraint value calculation unit is used to calculate the slope constraint for each section of the pipeline, specifically: ， ； in, This is the difference between the slope value and the maximum slope in the slope constraint for each pipeline segment. This is the difference between the slope value and the minimum slope in the slope constraint for each pipeline segment. The burial depth of the starting point in each section of the pipeline, The burial depth of the endpoint in each section of the pipeline. The length of each pipe segment, and Based on the minimum and maximum slopes specified in urban planning data and pipeline design specifications; The slope constraint determination unit is used to calculate based on pipeline parameters when there is a constraint. or When the result is greater than 0, it is determined that the pipeline parameters exceed the constraint conditions.

12. The drainage area pipeline design device according to claim 10, characterized in that, The upstream and downstream constraint unit includes: an upstream and downstream constraint value calculation unit and an upstream and downstream constraint determination unit; The upstream and downstream constraint value calculation unit is used to calculate the upstream and downstream constraints of each pipeline segment, specifically: ， ； in, Subtract the burial depth of the downstream pipeline from the starting burial depth of the upstream pipeline for each pipeline segment. Subtract the diameter of the downstream pipe from the diameter of the upstream pipe for each pipe segment. The burial depth of the upstream pipeline for each pipeline. The burial depth of the downstream end point of each pipeline. For each pipeline, the diameter of the upstream pipeline is... For each pipeline, the diameter of the downstream pipeline is specified. The upstream and downstream constraint determination unit is used to calculate based on pipeline parameters when there are constraints. or When the result is greater than 0, it is determined that the pipeline parameters exceed the constraint conditions.

13. The drainage area pipeline design device according to claim 9, characterized in that, The genetic algorithm module includes: a pipeline maximum burial depth calculation unit and a pipeline maximum diameter calculation unit; The pipeline maximum burial depth calculation unit is used to determine the pipeline maximum burial depth as the maximum value among the endpoint burial depths of all pipelines in the regional design scheme; The maximum pipe diameter calculation unit calculates the maximum pipe diameter as the maximum value among all pipe diameters in the regional design scheme.

14. The drainage area pipeline design device according to claim 9, characterized in that, The design scheme selection module includes: a regional design scheme sorting unit and a final design scheme determination unit; The regional design scheme sorting unit is used to sort all regional design schemes in the first dominant set according to the pipeline parameter weight standard; The final design scheme determination unit is used to obtain the top-ranked regional design scheme as the final drainage regional design scheme.

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