Method for realizing reversible conversion between water transportation lower boundary variable and unbounded variable and related product

Abstract

The invention provides a method for realizing reversible conversion between a lower boundary variable and an unbounded variable in water transportation and a related product. The method comprises the following steps of: valuing the lower bounded variable; converting the lower bounded variable into an unbounded variable; mathematical transformation of bounded variables and unbounded variables is proved to be reversible; proving that the first-order derivative at the forward transformation segmentation point is continuous; and proving that the first-order derivative at the inverse transformation segmentation point is continuous. The method has the beneficial effect that the bounded variable of the water transportation lower boundary is successfully converted into the unbounded variable. The conversion can meet the requirements of a part of mathematical assimilation methods and mathematical models for unbounded variables in the water transportation information processing and water transportation variable simulation and prediction processes. According to the method, the basic hypothesis of the peripheral nested algorithm is not damaged, the continuity of the algorithm is ensured, and the introduction of new errors is prevented. From the theoretical level, the assimilation precision of the peripheral nested data and the correction precision of the model correction model are higher, and the algorithm is more stable.

Description

Technical Field

[0001] The present invention belongs to the field of water transportation element processing, and in particular, relates to a method and related products for realizing reversible conversion between water transportation lower boundary variables and unbounded variables. Background Art

[0002] In the construction of water transportation intelligence, a series of observable water transportation elements and computable and predictable water transportation variables need to be processed, and data fusion is carried out by using technologies such as big data and large models. Among the commonly used technical means is data assimilation, that is, combining observation data with model prediction, using the observation results to correct (or rectify) the prediction results, and assimilating to obtain a better result on the basis of comprehensively considering observation errors and prediction errors, and continuously updating the model calculation. The water transportation elements (or water transportation variables) involved include unbounded variables, two-sided bounded variables, lower boundary bounded variables, and upper boundary bounded variables. Unbounded variables include: flow velocity (a positive value indicates the same direction as the specified direction, and a negative value indicates the opposite direction to the specified direction), wind speed, etc.; two-sided bounded variables include: water temperature (0 - 100 degrees Celsius), humidity (0 - saturated humidity), lock operation water level (design lowest - design highest), upstream dam water level of the hub (dead water level - design highest), etc.; lower boundary bounded variables include: rainfall (greater than or equal to 0), snowfall, water depth, etc.; upper boundary bounded variables include: potential energy difference of the water flow relative to the source (less than or equal to 0), soil water suction (when the soil reaches the saturated state, the soil water suction is 0, and the soil water suction is often represented by a negative number), etc.

[0003] When performing data assimilation or robust correction on the observed values of the above water transportation elements or the calculated values of water transportation variables, it is often necessary to introduce mathematical models or signal control algorithms such as Kalman filtering and gradient descent method. Many of these models (or algorithms) have good natural applicability to unbounded variables, but poor applicability to bounded variables, and the effect is poor when directly applied to the observation of water transportation bounded elements or the correction of calculated variables. There will be a situation where the calculated result after correction exceeds the limited boundary. The conventional method is to insert an intermediate step in the algorithm to forcibly adjust the corrected result back within the boundary conditions. This will cause the original basic assumptions of the algorithm to be violated and break the continuity of the algorithm, thereby introducing unestimable new errors in the process, resulting in the failure of model correction or the collapse of the algorithm, and ultimately affecting the effect of data assimilation.

[0004] The above problems are most difficult to handle with one-sided bounded variables (i.e., lower-bound bounded variables and upper-bound bounded variables). Taking the lower-bound bounded variable as an example, since the lower-bound bounded variable has only one-sided boundary condition restrictions (i.e., the lower-bound condition exists, and the upper-bound is an open boundary). In the process of data assimilation (or error correction), the stability of the two sides of the boundary is different. Correspondingly, it is also more difficult to convert it into an unbounded variable. It is necessary to segment (or divide the interval) the upper and lower boundaries, and ideally, the results of each segment (each interval) after conversion should be continuous and smooth. Mathematically, that is, ideally, the function after conversion is required to be continuous, and preferably, the first-order derivative function is continuous. In view of the above situation, taking the lower-bound bounded variable as an example, developing a method that can map the lower-bound bounded variable of water transportation into an unbounded variable is an effective idea to solve this problem. However, a scheme for inversely transforming the mapped unbounded variable back to the original variable must be supported. Thus, the reversible conversion between the lower-bound bounded variable and the unbounded variable of water transportation is realized. Summary of the Invention

[0005] In view of this, the present invention aims to propose a method and related products for realizing the reversible conversion between the lower-bound variable and the unbounded variable of water transportation to solve at least one of the above problems existing in the prior art.

[0006] To achieve the above object, the technical solution of the present invention is realized as follows:

[0007] A method for realizing the reversible conversion between the lower-bound variable and the unbounded variable of water transportation includes the following steps:

[0008] S1. Select the lower-bound variable among the water transportation variable parameters and take values for the lower-bound variable;

[0009] S2. Convert the lower-bound variable into an unbounded variable;

[0010] S3. Prove that the mathematical transformation between the lower-bound variable and the unbounded variable is reversible;

[0011] S4. Prove that the first-order derivative is continuous at the positive transformation segmentation point;

[0012] S5. Prove that the first-order derivative is continuous at the inverse transformation segmentation point.

[0013] Further, in step S1, selecting the lower-bound variable among the water transportation variable parameters and taking values for the lower-bound variable includes:

[0014] Let any lower-bound variable x, the lower boundary of its value range is x = LB, and the upper boundary is open, that is, the upper boundary of the value range is x = +∞, and the value range span is (LB, +∞).

[0015] Further, in step S2, converting the lower-bound variable into an unbounded variable includes:

[0016] It is assumed that there exists a point x = LiX and y = LiX. Taking this point as the dividing line, when x ≥ LiX, x and y satisfy the linear function relationship of y = x;

[0017] When LB < x < LiX, the bounded variable x with a lower boundary is transformed into an unbounded variable y through the following function:

[0018]

[0019] Therefore, the complete transformation function is expressed in the form of a piecewise function as follows:

[0020]

[0021] At this time, the value range of the transformed y is (-∞, +∞). Correspondingly, if it is necessary to reverse-transform the unbounded variable y back to the original bounded variable x with a lower boundary, the inverse function of f(x) is used, that is:

[0022]

[0023] Furthermore, in step S3, it is proved that the mathematical transformation between the bounded variable with a lower boundary and the unbounded variable is reversible, including:

[0024] Let x be an arbitrary bounded variable with a lower boundary, the lower boundary of its value range is x = LB, and the upper boundary is open, that is, the upper boundary of the value range is x = +∞; the value range span is (LB, +∞);

[0025] First, perform a transformation to transform the variable x into an unbounded variable y, that is:

[0026]

[0027] When the value range of x is LB < x < LiX, the corresponding value range of the transformed y is y < LiX; if a reverse transformation is performed again to transform the unbounded variable y into the variable x_new, then by looking up the transformation function in the corresponding interval, it can be known that:

[0028]

[0029] When the value range of x is LiX ≤ x, the corresponding value range of y is LiX ≤ y; then, similarly, perform a reverse transformation again to transform the unbounded variable y into the variable x_new, and the corresponding mathematical process is:

[0030] x_new = f -1 (y) = y = x.

[0031] Furthermore, in step S4, it is proved that the first derivative is continuous at the positive transformation segmentation point, including:

[0032] The value range (LB, +∞) of the lower-bound bounded variable is divided into two parts, namely: (LB, LiX) and [LiX, +∞); within the first interval, the transformation function f(x) is differentiated, that is, when LB < x < LiX:

[0033]

[0034] When x → LiX, the first derivative of the conversion function is:

[0035]

[0036] Within the second interval, the transformation function f(x) is differentiated, that is, when LiX ≤ x:

[0037] y′ = f′(x) = 1;

[0038] Therefore, the first derivative of the proposed transformation method is continuous at the segmentation point x = LiX.

[0039] Furthermore, in step S5, proving that the first derivative is continuous at the inverse transformation segmentation point includes:

[0040] The inverse transformation has two intervals, y < LiX and LiX ≤ y; when y < LiX, the derivative function of the inverse transformation function is:

[0041]

[0043] When y → LiX, the first derivative of the inverse transformation function is:

[0044]

[0045] When LiX ≤ y, the first derivative of the inverse transformation function is:

[0046] x' = [f -1 (y)]' = 1;

[0047] Therefore, the first derivative of the inverse transformation process is continuous at the segmentation point y = LiX.

[0048] An electronic device includes a processor and a memory communicatively connected to the processor and used to store instructions executable by the processor, and the processor is used to execute the method for realizing the reversible conversion between the water transport lower-bound variable and the unbounded variable.

[0049] A server includes at least one processor and a memory communicatively connected to the processor. The memory stores instructions executable by the at least one processor. When the instructions are executed by the processor, the at least one processor is caused to execute the method for realizing the reversible conversion between the water transport lower boundary variable and the unbounded variable.

[0050] A computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the method for realizing the reversible conversion between the water transport lower boundary variable and the unbounded variable is realized.

[0051] Compared with the prior art, the method and related products for realizing the reversible conversion between the water transport lower boundary variable and the unbounded variable according to the present invention have the following advantages:

[0052] (1) For the method and related products for realizing the reversible conversion between the water transport lower boundary variable and the unbounded variable according to the present invention, the method proposed by the present invention successfully realizes the conversion of the water transport lower boundary bounded variable into the unbounded variable. This conversion can meet the requirements of some mathematical assimilation methods and mathematical models for unbounded variables during the water transport information processing and the water transport variable simulation and prediction processes. Compared with the traditional method of "adding intermediate steps in the algorithm and forcibly adjusting the corrected result within the boundary condition range", the present invention can ensure the continuity of the algorithm without destroying the basic assumptions of these peripheral nested algorithms and prevent the introduction of new errors. From a theoretical perspective, this makes the correction accuracy of the peripheral nested data assimilation and model correction models higher and the algorithm more stable.

[0053] (2) For the method and related products for realizing the reversible conversion between the water transport lower boundary variable and the unbounded variable according to the present invention, the method proposed by the present invention divides the value range (LB, +∞) of the lower boundary bounded variable into two parts, namely: (LB, LiX) and [LiX, +∞). In the first interval, a conversion relationship is constructed based on the logarithmic function, and after conversion, the lower boundary extends infinitely towards -∞; in the second interval, the linear function conversion relationship of y = x is directly adopted, and the first derivative is continuous at the transition point between the two intervals. The overall idea is simple and clear, enabling those who use the present invention to intuitively grasp the corresponding relationship between the x and y variables before and after conversion. In addition, since the conversion relationship of y = x is used in the second interval, the nature of the variables before and after conversion is ensured not to change in most cases, which is beneficial to reducing the complexity of possible scientific problem analysis.

[0054] (3) A method and related products for realizing reversible conversion between water transport lower boundary variables and unbounded variables according to the present invention. The method proposed by the present invention has reversibility. Moreover, this reversible conversion is based on pure mathematical formulas, rather than establishing a mapping table for one-to-one correspondence and intermediate interpolation. Such a characteristic enables the present invention to be used as a pre-stage or post-stage converter for any mathematical method, and thus avoids the complex operations of establishing and querying the mapping table. Since there is no intermediate interpolation, interpolation errors are also avoided, reducing the memory occupation of the calculation module and accelerating the calculation speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0056] Figure 1 It is a schematic diagram of the reversible transformation process between the lower boundary bounded variable x and the unbounded variable y according to the embodiment of the present invention;

[0057] Figure 2 It is a schematic diagram of the method flow according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0059] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0060] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0062] As Figures 1 to 2 shown, a method for realizing the reversible conversion between the lower-bound variable and the unbounded variable of water transportation includes the following steps:

[0063] S1. Select the lower-bounded variable among the water transportation variable parameters and take the value of the lower-bounded variable.

[0064] S2. Convert the lower-bounded variable into an unbounded variable.

[0065] S3. Prove that the mathematical transformation between the lower-bounded variable and the unbounded variable is reversible.

[0066] S4. Prove that the first-order derivative is continuous at the positive transformation segmentation point.

[0067] S5. Prove that the first-order derivative is continuous at the inverse transformation segmentation point.

[0068] In a preferred embodiment of the present invention, the method includes:

[0069] Let any lower-bounded variable x have the lower boundary of its value range as x = LB and the upper boundary open, that is, the upper boundary of the value range is x = +∞, and the value range span is (LB, +∞). Now it is necessary to convert this lower-bound bounded variable x into an unbounded variable y, that is, it is required that the value range of y after conversion is (-∞, +∞).

[0070] The method provided by the present invention is: assume that there exists a point x = LiX, y = LiX, and taking this point as the dividing line, when x ≥ LiX, x and y satisfy the linear function relationship of y = x.

[0071] Before this, that is, when LB < x < LiX, the lower-bound bounded variable x is converted into an unbounded variable y through the following function:

[0072]

[0073] Therefore, the complete transformation function can be expressed in the form of a piecewise function as follows:

[0074]

[0075] Correspondingly, if it is necessary to reversely transform (or inverse-transform) the unbounded variable y back to the original lower-bounded variable x with a lower boundary, the inverse function of f(x) needs to be used, that is:

[0076]

[0077] Prove that this mathematical transformation is invertible:

[0078] Let x be an arbitrary lower-bounded variable, the lower boundary of its value range is x = LB, and the upper boundary is open, that is, the upper boundary of the value range is x = +∞. The value range span is (LB, +∞). Using the method provided by the present invention, first perform a transformation to transform the variable x into an unbounded variable y, that is:

[0079]

[0080] It can be seen that when the value range of x is LB < x < LiX, the corresponding range of the transformed y is y < LiX. If a reverse transformation is performed again to transform the unbounded variable y into the variable x_new, then by looking up the transformation function of the corresponding interval, it can be known that:

[0081]

[0082] When the value range of x is LiX ≤ x, the corresponding range of y is LiX ≤ y. Then, similarly, perform a reverse transformation again to transform the unbounded variable y into the variable x_new, and the corresponding mathematical process is:

[0083] x_new = f -1 (y) = y = x;

[0084] In summary, for any lower-bounded variable x, applying the method proposed by the present invention, performing a transformation and then an inverse transformation, the obtained x_new satisfies x_new = x. Therefore, the method for mutually converting the lower-bound variable and the unbounded variable proposed by the present invention is reversible mathematically.

[0085] Prove that the first derivative is continuous at the positive transformation segmentation point:

[0086] The method proposed by the present invention divides the value range (LB, +∞) of the lower-bounded variable into two parts, that is: (LB, LiX) and [LiX, +∞). In the first interval, the transformation function f(x) is differentiated, that is, when LB < x < LiX:

[0087]

[0088] When x → LiX, the first derivative of the conversion function is:

[0089]

[0090] In the second interval, the transformation function f(x) is differentiated, that is, when LiX ≤ x:

[0091] y' = f'(x) = 1;

[0092] Therefore, the first derivative of the proposed transformation method is continuous at the segmentation point x = LiX.

[0093] Prove that the first derivative of the inverse transformation is continuous at the segmentation point:

[0094] Similarly, the inverse transformation also has two intervals, y < LiX and LiX ≤ y. When y < LiX, the derivative function of the inverse transformation function is:

[0095]

[0096] When y → LiX, the first derivative of the inverse transformation function is:

[0097]

[0098] When LiX ≤ y, the first derivative of the inverse transformation function is:

[0099] x' = [f -1 (y)]' = 1;

[0100] Therefore, the first derivative of the inverse transformation process is also continuous at the segmentation point y = LiX.

[0101] The present invention also provides an electronic device, including a processor and a memory communicatively connected to the processor and configured to store executable instructions of the processor, where the processor is configured to execute the method for realizing the reversible conversion between the water transport lower boundary variable and the unbounded variable.

[0102] The present invention also provides a server, including at least one processor and a memory communicatively connected to the processor, where the memory stores instructions executable by the at least one processor, and the instructions are executed by the processor to enable the at least one processor to execute the method for realizing the reversible conversion between the water transport lower boundary variable and the unbounded variable.

[0103] The present invention also provides a computer-readable storage medium storing a computer program, where the computer program, when executed by a processor, realizes the method for realizing the reversible conversion between the water transport lower boundary variable and the unbounded variable.

[0104] Advantages of the present invention:

[0105] (1) The method proposed by the present invention successfully realizes the transformation of the lower boundary bounded variable in water transportation into an unbounded variable. This transformation can meet the requirements of some mathematical assimilation methods and mathematical models for unbounded variables during the process of water transportation information processing and water transportation variable simulation and prediction. Compared with the traditional method of "adding intermediate steps in the algorithm and forcibly adjusting the corrected result within the boundary conditions", the present invention can not damage the basic assumptions of these peripheral nested algorithms, ensure the continuity of the algorithm, and prevent the introduction of new errors. In terms of theory, this makes the correction accuracy of the peripheral nested data assimilation and model correction model higher, and the algorithm is more stable.

[0106] (2) The method proposed by the present invention divides the value range (LB, +∞) of the lower boundary bounded variable into two parts, namely: (LB, LiX) and [LiX, +∞). In the first interval, a conversion relationship is constructed based on the logarithmic function. After conversion, the lower boundary extends infinitely to -∞; in the second interval, the linear function conversion relationship of y = x is directly adopted, and the first-order derivative is continuous at the transition point between the two intervals. The overall idea is simple and clear, enabling the personnel using the present invention to intuitively grasp the corresponding relationship between the x and y variables before and after conversion. In addition, since the conversion relationship of y = x is used in the second interval, it is ensured that the nature of the variables before and after conversion is not changed in most cases, which is beneficial to reducing the complexity of possible scientific problem analysis.

[0107] (3) The method proposed by the present invention is reversible. Moreover, this reversible conversion is based on pure mathematical formulas, rather than establishing a mapping table for one-to-one correspondence and intermediate interpolation. Such a characteristic enables the present invention to be used as a pre-stage or post-stage converter for any mathematical method, and this avoids the complex operations of establishing a mapping table and querying the mapping table. Because there is no intermediate interpolation, it also avoids introducing interpolation errors, reduces the memory occupation of the calculation module, and speeds up the calculation speed.

[0108] Example 1:

[0109] Suppose a water transportation variable x represents water depth, the river bottom elevation of the river channel is -2m, and the maximum water depth is unknown, which is an open boundary. That is, theoretically, the value range of the water depth x is (-2, +∞) meters. Then, the water transportation variable x can be regarded as a typical lower boundary bounded variable. In order to meet the requirements of some mathematical assimilation methods and mathematical models for unbounded variables, it is necessary to transform it into an unbounded variable y. And it is required that this transformation is reversible mathematically.

[0110] Applying the method of the present invention, the steps are as follows:

[0111] ① Identify the lower boundary point of x and set the conversion parameter LiX. The conversion parameter can be set as needed, only need to meet LiX > LB. In this embodiment,

[0112] LB = -2;

[0113] LiX = 5;

[0114] ② Using the calculation module, apply the formula proposed in the present invention to construct the corresponding conversion function, convert the lower-bound bounded variable x into the unbounded variable y, output the result and store it in the result storage module as follows:

[0115]

[0116] ③ If it is necessary to inversely transform the unbounded variable y back to the lower-bound bounded variable x, then use the calculation module, apply the formula proposed in the present invention to construct the corresponding inverse conversion function, output the result and store the result in the result storage module as follows:

[0117]

[0118] The schematic diagram of the reversible transformation process between the lower-bound bounded variable x and the unbounded variable y in this embodiment is as Figure 1 shown. Among them, Figure 1 in, (a) represents the process of converting the lower-bound bounded variable x into the unbounded variable y. (b) represents the relationship between the original lower-bound bounded variable x and the x_new obtained after two conversions. (c) represents the process of inversely converting the unbounded variable y back to the lower-bound bounded variable (using x_new to represent the inverse conversion result, distinguished from the initial variable x).

[0119] From Figure 1 it can be seen that the method proposed in the present invention divides the value range (-2, +∞) of the lower-bound bounded variable into two parts, namely: (-2, 5) and [5, +∞). In the first interval ( Figure 1 . the range marked in cyan blue), a conversion relationship is constructed based on the logarithmic function. After conversion, the lower boundary extends infinitely to -∞; in the second interval, the linear function conversion relationship of y = x is directly adopted, and the first-order derivative is continuous at the transition point between the two intervals.

[0120] In this embodiment, the conversion processes in two interval ranges are given as examples. In the first interval, x1 = 1, and the corresponding y1 = -0.9311 after conversion. After another inverse conversion calculation, the obtained x_new1 = 1; in the second interval, x2 = 15, and the corresponding y2 = 15 after conversion. After another inverse conversion calculation, the obtained x_new2 = 15. Intuitively, it shows that the conversion method proposed in the present invention is reversible.

[0121] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for realizing reversible conversion between lower bound variables and unbounded variables in water transport, characterized in that: It includes the following steps: S1. Select the lower-bounded variables among the water transportation variable parameters and assign values to the lower-bounded variables. S2. Transform the lower-bounded variables into unbounded variables. S3. Prove that the mathematical transformation between the lower-bounded variables and the unbounded variables is reversible. S4. Prove that the first derivative is continuous at the positive transformation segmentation point. S5. Prove that the first derivative is continuous at the inverse transformation segmentation point.

2. A method for realizing reversible conversion between lower bound variables and unbounded variables in water transport according to claim 1, characterized in that: In step S1, when selecting the lower-bounded variables among the water transportation variable parameters and assigning values to the lower-bounded variables, it includes: Let any lower-bounded variable be x, the lower boundary of its value range is x = LB, and the upper boundary is open, that is, the upper boundary of the value range is x = +∞, and the value range span is (LB, +∞).

3. A method for realizing reversible conversion between lower bound variables and unbounded variables in water transport according to claim 1, characterized in that: In step S2, when transforming the lower-bounded variables into unbounded variables, it includes: It is assumed that there is a point x = LiX, y = LiX. Taking this point as the demarcation line, when x ≥ LiX, x and y satisfy the linear function relationship of y = x. When LB < x < LiX, the variable x with a bounded lower boundary is transformed into an unbounded variable y through the following function: Therefore, the complete transformation function is expressed in the form of a piecewise function as follows: At this time, the value range of the transformed y is (-∞, +∞). Correspondingly, if it is necessary to reversely transform the unbounded variable y back to the original variable x with a bounded lower boundary, the inverse function of f(x) is used, that is:

4. A method for realizing reversible conversion between lower bound variables and unbounded variables in water transport according to claim 1, characterized in that: In step S3, when proving that the mathematical transformation between the lower-bounded variables and the unbounded variables is reversible, it includes: Let x be any lower-bounded variable, the lower boundary of its value range is x = LB, and the upper boundary is open, that is, the upper boundary of the value range is x = +∞; the value range span is (LB, +∞); First, perform a transformation to transform the variable x into an unbounded variable y, that is: When the value range of x is LB < x < LiX, the corresponding value range of the transformed y is y < LiX; if a reverse transformation is performed again to transform the unbounded variable y into the variable x_new, then by looking up the transformation function in the corresponding interval, it can be known that: When the value range of x is LiX ≤ x, the corresponding value range of y is LiX ≤ y; then, similarly, when performing a reverse transformation again to transform the unbounded variable y into the variable x_new, the corresponding mathematical process is: x_new=f -1 (y)=y=x。 5. A method for realizing reversible conversion between lower bound variables and unbounded variables in water transport according to claim 1, characterized in that: In step S4, when proving that the first derivative is continuous at the positive transformation segmentation point, it includes: The value range (LB, +∞) of the variable with a bounded lower boundary is divided into two parts, that is: (LB, LiX) and [LiX, +∞); within the first interval, the transformation function f(x) is differentiated, that is, when LB < x < LiX: When x → LiX, the first derivative of the conversion function is: Within the second interval, the transformation function f(x) is differentiated, that is, when LiX ≤ x: y' = f'(x) = 1; Therefore, the proposed transformation method has a continuous first derivative at the segmentation point x = LiX.

6. A method for realizing reversible conversion between lower bound variables and unbounded variables in water transport according to claim 1, characterized in that: In step S5, when proving that the first derivative is continuous at the inverse transformation segmentation point, it includes: For the inverse transformation, there are two intervals, y < LiX and LiX ≤ y; when y < LiX, the derivative function of the inverse transformation function is: When y → LiX, the first derivative of the inverse transformation function is: When LiX ≤ y, the first derivative of the inverse transformation function is: x'=[f -1 (y)]'=1; Therefore, the inverse transformation process is continuous in the first-order derivative at the split point y=LiX.

7. An electronic device, comprising a processor and a memory connected to the processor for storing instructions executable by the processor, characterized in that: The processor is used to execute the method for realizing reversible conversion between lower boundary variables and unbounded variables in water transport as described in any one of claims 1-6 above.

8. A server, characterized in that: It includes at least one processor and a memory communicatively connected to the processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the processor so that the at least one processor executes the method for realizing reversible conversion between water transport lower boundary variables and unbounded variables as described in any one of claims 1-6.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, it implements the method for realizing reversible conversion between lower boundary variables and unbounded variables in water transport as described in any one of claims 1-6.

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