KR20200101563A - Measurement of suspended sediment concentration by multiple regression analysis using ultrasonic reflectance and depth - Google Patents

Abstract

The present invention relates to a method for estimating a suspended load concentration of a river. According to the present invention, the method for estimating a suspended load concentration of a river comprises: a step (S100) of checking an actually measured suspended load concentration (SSC_(msr)); a step (S110) of filtering an ultrasonic reflectance; a step (S120) of calculating a suspended load concentration predictive value (SSC_(pdt)); and a step (S130) of determining a suspended load concentration estimated value (SSC) of an entire river. According to the present invention, the accuracy can be remarkably increased.

Description

Method of estimating suspended sediment concentration by multiple regression analysis using ultrasonic reflectance and depth}

The present invention is a method of estimating suspended solids concentration through multiple regression analysis using ultrasonic reflectance and water depth, and more particularly, a confidence range in the transverse direction of a river using a correlation coefficient between the ultrasonic reflectance and the measured suspended solids concentration. And performing multiple regression analysis using information on ultrasonic signal reflectance and water depth, the present invention relates to a method for estimating suspended solids concentration with increased accuracy.

'Buyusa' is a collective term for soil that is moved underwater by floating from the bottom by the flow or wave of water in a river or coast. The information on the particle size, distribution, or concentration per volume of such suspended sand becomes basic information in characterizing the behavior of erosion and sedimentary environments in rivers or coastal areas. Furthermore, big data obtained by continuously accumulating the above-described information on floating history can be used as important information for predicting topographic changes in rivers or coastal areas, so research on this is actively underway. to be.

To measure suspended solids moving underwater, Aquadopp Profiler (Side looking), Aquadopp Profiler (500khz), Vector 3d Acoustic Velocimeter (Fixed Stem Standard), PC-ADP (Pulse-Coherent ADP), Signature, ABS (Acoustic Backscatter) System), Sequoia (LISST-100X), etc. have already been commercialized and provided.

The method of estimating suspended solids is divided into an indirect method, which is calculated by substituting data on the water volume and bed soil characteristics into the sediment amount formula, and a method of directly measuring the sediment amount. Currently, the direct investigation method using a sediment collector is mainly used for observation of sediment masses in Korea.However, the field measurement using a sediment collector is very difficult and a lot of manpower and time are consumed, so it is difficult to measure at multiple points simultaneously and continuously.

Accordingly, the security of similar quantity data is very insufficient during the flood period due to the problem of access to the river and the limitations of conventional measurement methods. In addition, in domestic rivers, the hydraulic characteristics of rivers tend to change during the flood period, so the flow rate-similarity relation, which is used as an alternative, has low reliability and is difficult to update frequently.

As a prior art, Korean Patent Registration No. 10-0851467 is disclosed. The prior art relates to a technique capable of unmanned operation by continuously measuring the floating radiation amount of a river by the depth of the river, and the floating radiation amount as a device for measuring the amount of floating radiation, which has an underwater flow rate derivative, a radiation source, and a radiation detector. It is not a description of the indirect calculation method. As described above, the prior art also relates to a method of directly measuring the similar amount, and thus, it is still not possible to solve the troublesome problem of measurement.

Accordingly, in recent years, there is a need for a method of indirectly estimating the amount of suspended solids in the river, but increasing the accuracy of the amount of suspended solids.

(Patent Document 1) Korean Patent Registration No. 10-0851467

The present invention has been conceived to solve the problems of the prior art, and intends to propose a method for estimating suspended solid concentration with improved accuracy, but derived indirectly, rather than directly measuring the suspended solid concentration by a measurer.

In addition, by proposing a method for estimating not only the flow rate but also the suspended solid concentration through the transverse ultrasonic Doppler velocimetry, which was previously used only to estimate the flow rate of the river, additional facilities for estimating the suspended solid concentration will be provided. We would like to propose a method for estimating the floating farm concentration that is not necessary.

The present invention for solving the above problems is a method of estimating the suspended concentration of a river, by generating an ultrasonic signal in a transverse direction under the water surface of the river, and sensing the reflected signal of the generated ultrasonic signal to detect the ultrasonic signal reflectance. An ultrasonic signal unit (S) for measuring is provided, and (a0) confirming the measured _{suspended solid} concentration (SSC _msr ) (S100); (a1) In the ultrasonic signal filtering module 110, information on the ultrasonic signal reflectance is transmitted from the ultrasonic signal unit S, and the ultrasonic reflectance within a certain range is filtered based on the transverse direction, which is the direction in which the ultrasonic signal is generated. The step (S110); (a2) In the iterative calculation module 120, the estimated _suspended solids concentration (SSC _pdt ) is calculated using the ultrasonic reflectance in the above range, but by changing an arbitrary range within the width of the river, the estimated _suspended solids concentration ( by performing the calculation of the SSC _pdt) repeating the step of calculating the sediment concentration estimated value for the respective range (SSC _pdt) (S120); And (a3) in the range setting module 130, the correlation between the estimated _suspended solids concentration (SSC _pdt ) and the measured _suspended solids concentration (SSC _msr ) in each of the ranges calculated in the (a2) step (S120). Calculating a coefficient, determining a range when the correlation coefficient is the maximum as a confidence range, and determining an estimated suspended _solid concentration (SSC _pdt ) in the confidence range as an estimated total suspended _solid concentration (SSC) of the river ( S130); It provides a method for estimating the suspended solid concentration of the river, including.

In addition, the step (a1) (S110), correcting the ultrasonic reflectance (SCB) within the range, (a11) performing correction for the beam spread (S111); (a12) performing correction for absorption by water (S112); And (a13) performing attenuation correction by the floating yarn (S113). It is preferable to include.

In addition, in the step (a2) (S120), the estimated _suspension concentration (SSC _pdt ) in the range is calculated through linear regression analysis using the average ultrasonic reflectance (SCB _avg ) in the range as an independent variable. , It is preferable to derive the expected _suspended solids concentration (SSC _pdt ) by Equation 1 below.

<식 1>

<Equation 1>

In addition, in step (a2) (S120), it is preferable to repeatedly perform the calculation of the expected _suspension concentration value (SSC _pdt ) by changing the upper or lower limit of the range.

In addition, the present invention is a method of estimating the suspended concentration of a river, generating an ultrasonic signal in a transverse direction under the water surface of the river, recognizing the reflected signal of the generated ultrasonic signal to measure the ultrasonic signal reflectance, and measuring the depth of water. The ultrasonic signal unit S is provided, and (b1) the information input module 140 receives and inputs information on the ultrasonic signal reflectance and water depth from the ultrasonic signal unit S (S210). ; (b2) In the multiple regression analysis module 150, the step of determining a regression coefficient by performing multiple regression analysis using information on the ultrasonic signal reflectance and depth repeatedly inputted in step (b1) (S210) ( S220); And (b3) in the suspended solids concentration estimation module 160, using the regression coefficient determined in step (b2) (S220), and an ultrasonic signal reflectance (SCB); Depth; And a product of the ultrasonic signal reflectance (SCB) and the depth of water. Estimating the suspended solid concentration of the river by using as independent variables (S230); It provides a method for estimating the suspended solid concentration of the river, including.

In addition, in the step (b3) (S230), it is preferable to derive the river suspension concentration (SSC) by the following equation.

<Equation 2>

(β ₀ , β ₁ , β ₂ , β ₃ are regression coefficients)

In addition, the present invention is a method of estimating the suspended concentration of a river, in which an ultrasonic signal is generated in a transverse direction under the water surface of the river, and the ultrasonic signal reflectance is measured by recognizing the reflected signal of the generated ultrasonic signal S) is provided, and (c0) the step (S300) of checking the actual _{suspended solid} concentration (SSC _msr ); (c1) In the ultrasonic signal filtering module 110, information on the ultrasonic signal reflectance is transmitted from the ultrasonic signal unit S, and the ultrasonic reflectance within a certain range is filtered based on the transverse direction, which is the direction in which the ultrasonic signal is generated. A step (S310); (c2) In the iterative calculation module 120, the estimated _suspended solids concentration (SSC _pdt ) is calculated using the ultrasonic reflectance in the above range, but by changing an arbitrary range within the width of the river, the estimated _suspended solids concentration ( by performing the calculation of the SSC _pdt) repeating the step of calculating the sediment concentration estimated value for the respective range (SSC _pdt) (S320); (c3) In the range setting module 130, a correlation coefficient between the estimated _{suspended solid} concentration (SSC _pdt ) and the measured _{suspended solid} concentration (SSC _msr ) in the range calculated in the (c2) step (S320) Calculating, and determining a range when the correlation coefficient is maximum as a confidence range (S330); (c4) The information input module 140 receives and inputs information on the ultrasonic signal reflectance and depth within the confidence range determined in step (c3) (S330) from the ultrasonic signal unit (S). S340); (c5) In the multiple regression analysis module 150, by performing multiple regression analysis using information on the ultrasonic signal reflectance and depth in the confidence interval repeatedly inputted in step (c4) (S340), the regression coefficient Determining step (S350); And (c6) in the suspended solids concentration estimation module 160, using the regression coefficient determined in step (C5) (S350), and an ultrasonic signal reflectance (SCB); Depth; And a product of the ultrasonic signal reflectance (SCB) and the depth of water. Estimating the suspended solids concentration of the river using as independent variables (S360); It provides a method for estimating the suspended solids concentration in the river including.

In addition, the ultrasonic signal unit (S) is preferably an ultrasonic Doppler velocity meter.

In addition, the ultrasonic signal unit (S) is provided with a pressure sensor, it is preferable to derive the depth of the river by using the water pressure measured by the pressure sensor.

The present invention as described above has the following effects.

The method for estimating the suspended solid concentration in a river according to the present invention can derive a value very similar to the actual suspended solid concentration by performing multiple regression analysis with the depth of the water as an independent variable. It works.

In addition, in the method for estimating the suspended solids concentration in a river according to the present invention, the confidence range is determined by a specific method, and only the ultrasonic signal reflectance of the confidence range is selected and used. When the confidence range is determined, the accuracy is very simple thereafter. It is possible to estimate the high suspended solid concentration in the river, so it is possible to reduce the time and cost required for calculation.

1 is a schematic diagram schematically showing a state in which an ultrasonic signal unit used in a method for estimating a river suspension concentration according to the present invention is installed in a river.
2 is a schematic block diagram for explaining a first embodiment of a method for estimating a river suspension concentration according to the present invention.
3 is a graph showing the SNR, WCB and SCB according to the lateral distance from the lateral ultrasonic Doppler velocimetry.
4 is a flow chart of a first embodiment of a method for estimating a river suspension concentration according to the present invention.
5 is a schematic conceptual diagram for explaining a range change in the first embodiment of the method for estimating the suspended solids concentration in a river according to the present invention.
6 is a flowchart illustrating a process of correcting an ultrasonic reflectance according to the first embodiment of the present invention.
7A to 7E are graphs derived from correlation coefficients by varying the upper and lower limits of the range shown in FIG. 5, respectively.
FIG. 8 is a graph showing the relationship between the spatially averaged ultrasonic reflectance and the measured suspended concentration by setting a range based on d of FIG. 7.
9 is a schematic block diagram for explaining a second embodiment of a method for estimating a river suspension concentration according to the present invention.
10 is a flow chart of a second embodiment of the method for estimating the suspended solid concentration of a river according to the present invention.
Figure 11a is a graph showing the estimated value of suspended solids concentration and the actual measured suspended solids concentration under conditions not considering the depth of water, and Fig. 11b is It is a graph showing the estimated value and the measured suspended solid concentration.
12 is a flow chart of a third embodiment of a method for estimating a river suspension concentration according to the present invention.

Hereinafter, a method for estimating a river suspended solid concentration according to the present invention will be described with reference to the drawings. The'lateral direction' used hereinafter refers to a horizontal direction, but it is specified in advance that the ultrasonic signal may be generated in a direction having a predetermined angle upward from the ground, not in an exact horizontal direction.

1 is a schematic diagram schematically showing a state in which an ultrasonic signal unit used in a method for estimating a river suspension concentration according to the present invention is installed in a river.

As shown in Fig. 1, an ultrasonic signal unit (S) for measuring ultrasonic signal reflectance by generating an ultrasonic signal in a transverse direction under the water surface of a river, that is, underwater, and sensing the reflected signal of the generated ultrasonic signal is provided. do. At this time, a pressure sensor is provided on the upper part of the ultrasonic signal unit S, and the pressure sensor senses the water pressure to derive the depth of the river. To this end, the height from the bottom surface of the river to the position where the pressure sensor is provided is previously stored in the ultrasonic signal unit S.

The ultrasonic signal unit S includes an ultrasonic signal transceiving module, and is configured to generate an ultrasonic signal in a horizontal direction at preset time intervals and to sense a reflected signal reflected by a floating yarn flowing in a river. The ratio of the reflected signal to the generated ultrasonic signal is calculated to determine the ultrasonic signal reflectance. In addition, the ultrasonic signal unit S may be configured with an ultrasonic Doppler velocity meter.

Embodiment 1

2 is a schematic block diagram for explaining a first embodiment of a method for estimating a river suspension concentration according to the present invention.

The configuration for the method for estimating the suspended solid concentration in the river according to the first embodiment includes an ultrasonic signal filtering module 110, an iterative calculation module 120, and a range setting module 130.

The ultrasonic signal filtering module 110 is configured to receive information on the ultrasonic signal reflectance from the ultrasonic signal unit S, and is formed to filter only the ultrasonic reflectance within a certain range based on the transverse direction, which is the direction in which the ultrasonic signal is generated. . Here, an arbitrary range means a section between an arbitrary upper limit value and an arbitrary lower limit value within the width of the river.

The iterative calculation module 120 calculates the expected _suspended solids concentration (SSC _pdt ) by using the ultrasonic reflectance in the above range, but changes an arbitrary range within the width of the river to increase the estimated _suspended solids concentration (SSC _pdt ). By repeatedly performing the operation, it is configured to calculate an expected _suspension concentration value SSC _pdt for each of the ranges. Here, changing an arbitrary range within the width of the river means changing the upper or lower limit. That is, the iterative calculation module 120 calculates the expected _suspended solids concentration (SSC _pdt ) in a specific range, and automatically (or randomly) changes the specific range. At this time, changed by calculating the sediment concentration estimated value (SSC _pdt) each specific range, and sediment concentration estimate for the changed specific ranges, respectively (SSC _pdt) is the index, the index sediment concentration estimated value (SSC _pdt) May be configured to be stored in a database (not shown). In addition, the database may store a specific range and an expected _suspension concentration value (SSC _pdt ) for the specific range in ordered pairs.

On the other hand, the method of calculating the estimated _suspended solids concentration (SSC _pdt ) in the iterative calculation module 120 is calculated through linear regression analysis using the average ultrasonic reflectance (SCB _avg ) in the specific range as an independent variable, It is configured to derive the expected value of suspended solids concentration (SSC _pdt ) by 1.

[식 1]

[Equation 1]

The range setting module 130 is configured to compare the estimated _suspended solids concentration (SSC _pdt ) stored in the database with the actual _suspended solids concentration (SSC _msr ), and calculate a correlation coefficient through the comparison. The specific range when the correlation coefficient is at the maximum is determined as the confidence range. The estimated _suspended solids concentration (SSC _pdt ) derived based on the confidence range determined here is determined as the estimated total _suspended solids concentration (SSC). In this way, once the confidence range is determined, the average ultrasonic reflectance (SCB _avg ) is calculated by selecting only the ultrasonic reflectance within the confidence range, so that the _suspended concentration of the entire river can be easily estimated.

3 is a graph showing the SNR, WCB and SCB according to the lateral distance from the lateral ultrasonic Doppler velocimetry. Referring to FIG. 3, when measuring the flow rate with a transverse ultrasonic Doppler velocimetry, not only the flow velocity and the water depth, but also the ultrasonic reflectance data are measured and recorded in the raw data. The raw data of the measured ultrasonic reflectance is emitted from the signal unit and is measured in a form in which the ultrasonic reflectance decreases as the distance increases.

The SNR of FIG. 3 refers to raw data measured with a transverse ultrasonic Doppler velocimetry, and the ultrasonic reflectance of the raw data may be different for each manufacturer or product model, but SNR (in dB) or EI (Echo Intensity) , Count unit), the original data is recorded. Since the unit of EI is Count, it needs to be converted to dB, and the coefficient for conversion is converted using the coefficient provided by the manufacturer according to the specifications of each product. Preferably, a conversion factor of 0.43 can be applied.

The reason that the ultrasonic reflectance decreases with the distance of the original SNR value is the decrease due to the beam spreading according to the distance, the absorption of the ultrasonic signal by water, and the attenuation by the suspended substances present in the water. It is possible to indirectly estimate the suspended solid concentration through the relationship with the measured suspended solid concentration through the Sediment Corrected Backscatter (SCB), which is measured to be small and corrected accordingly.

The WCB of FIG. 3 is a result of the reduction due to the beam spreading according to the distance, and the absorption of the ultrasonic signal by water, and the SCB is the result of the beam spreading and water as shown in the flowchart of FIG. 6 for the ultrasonic reflectance (SNR) of the original data. This is the result showing the corrected ultrasonic reflectance by performing attenuation correction for absorption and suspended matter (floating).

As described above, the corrected ultrasonic reflectance (SCB) is obtained through the correction of the raw data of the ultrasonic Doppler flowmeter continuously measured as above, and only the data measured at the same time as the measured suspended concentration measurement time are extracted and the upper and lower limits are calculated. In the meantime, an arbitrary range for estimating the measured floating concentration is obtained through the calculation of the regression coefficient with the measured floating concentration. After obtaining an arbitrary range, the coefficient for predicting the measured floating density is obtained through multiple regression through the water level and the corrected ultrasonic reflectance, and the coefficient is applied to the measured data at each time to finally calculate the floating density. can do. This will be described in detail later.

4 is a flow chart of a first embodiment of a method for estimating a river suspension concentration according to the present invention. The first embodiment of the present invention includes steps (S100) to (S130).

Step (S100) is a step of checking the measured _{suspended solid} concentration (SSC _msr ). The first embodiment of the present invention requires a process of comparing the estimated _{suspended solid} concentration (SSC _pdt ) with the measured _{suspended solid} concentration (SSC _msr ), respectively, to check at least one or more measured _{suspended solid} concentration (SSC _msr ). You need a process.

In step S110, the ultrasonic signal filtering module 110 receives information on the ultrasonic signal reflectance from the ultrasonic signal unit S, and based on the transverse direction, which is the direction in which the ultrasonic signal is generated, the ultrasonic reflectance within a certain range. This is the step of filtering. The arbitrary range determines the upper and lower limits based on the transverse direction, which is the width direction of the river, and the frequency of the ultrasonic signal generated for each ultrasonic signal unit S may be different, and the travel distance of the ultrasonic signal may vary depending on the frequency. have. Therefore, it is preferable that an arbitrary range herein is set within the maximum reach of the ultrasonic signal generated by the ultrasonic signal unit S.

In the step (S120), in the iterative calculation module 120, the estimated suspended _solid concentration (SSC _pdt ) is calculated using the ultrasonic reflectance in the above range, but the suspended _solid concentration is predicted by changing an arbitrary range within the width of the river. value by performing an operation of the repeat (SSC _pdt), a step for calculating the sediment concentration estimated value for the respective range (SSC _pdt). In step S120, the calculation of the expected _suspended solids concentration (SSC _pdt ) is repeatedly performed, and the number of repetitions will be the same as the number of changes in the range. Meanwhile, in the present specification, the range is described as an example as a continuous range having a single upper limit value and a lower limit value, but an arbitrary range may be formed in a plurality, in which case, it has a plurality of upper and lower limits, and discontinuously It can also be formed.

Step (S130), in the range setting module 130, calculates a correlation coefficient between the estimated _suspended solids concentration (SSC _pdt ) and the measured _suspended solids concentration (SSC _msr ) in each of the ranges calculated in step (S120), and , The range at which the correlation coefficient is the maximum is determined as the confidence range, and the estimated suspended _solid concentration (SSC _pdt ) in the confidence range is determined as the estimated total suspended _solid concentration (SSC) of the river. Here, the measured _{suspended solid} concentration (SSC _msr ) uses the value identified in the above-described step (S100).

5 is a schematic conceptual diagram for explaining a range change in the first embodiment of the method for estimating the suspended solids concentration in a river according to the present invention. Referring to FIG. 5, the range may be configured as a first to Nth range in a transverse direction based on the entire width of the river. The upper and lower limits of each of the first to Nth ranges are formed to be different from each other. When the upper limit is the same, the lower limit is different, and when the lower limit is the same, the upper limit is different.

6 is a flowchart illustrating a process of correcting an ultrasonic reflectance according to the first embodiment of the present invention. The above-described step (S110) further includes a process of correcting the ultrasonic reflectance (SCB) within the above range. Specifically, it includes steps (S111) to (S113).

Step S111 is a step of performing correction for beam spreading. Step (S112) is a step of performing a correction for absorption by water, step (S113) is a step (S113) of performing attenuation correction by the floating sand.

Specifically, the method of estimating the concentration of suspended solids using the ultrasonic reflectance of the transverse ultrasonic Doppler velocimetry in the river is based on Urick's sonar equation as shown in Equation 2.

[식 2]

[Equation 2]

Here, RL (reverberation level) refers to the measured ultrasonic signal, SL (source level) refers to the actually emitted ultrasonic signal, and 2TL (two-way transmission loss) refers to the diffusion and attenuation of ultrasonic waves generated in both directions, and TS is caused by particles. It means the intensity of the echoed signal. The equations for the loss, diffusion, and attenuation of the two-way ultrasound are as shown in Equation 3 below.

[식 3]

[Equation 3]

The first term on the right of Equation 3 means correction for beam spreading, and the second term means absorption by water and attenuation correction by similarity, respectively. And if you use Equation 2 and Equation 3 to organize it, it is the same as Equation 4 and Equation 5.

[식 4]

[Equation 4]

[식 5]

[Equation 5]

Here, MB (Measured backscatter) in Equation 4 means the measured ultrasonic reflectance signal, and WCB (Water corrected backscatter) means the result of performing correction for the measured ultrasonic reflectance and beam spread, and absorption correction by water. , SCB (Sediment Corrected Backscatter) refers to the ultrasonic reflectance finally corrected by performing attenuation correction by similarity. At this time, if it is assumed that the transverse suspended solid concentration at the point where the transverse ultrasonic Doppler velocity meter is installed is constant, Equation 5 can be summarized as Equation 6.

[식 6]

[Equation 6]

Using Equation 6, the attenuation correction (α _s ) due to similarity can be calculated as Equation 7.

[식 7]

[Equation 7]

Therefore, if the concentration in the transverse direction is assumed to be constant, the attenuation correction (α _s ) due to the similarity is ??1/2 of the slope calculated through the linear regression of the WCB measured from each cell with a transverse ultrasonic Doppler velocity meter. It can be calculated by multiplying.

Each correction method for the ultrasonic reflectance measured from the transverse ultrasonic Doppler velocimetry is as follows. Correction for beam spread means correcting for the spread of ultrasonic waves emitted from the ADCP transducer. In general, it is assumed that ultrasonic waves spread out evenly according to distance, but since ultrasonic waves are irregular and nonspherical in the near field, correction is required by calculating a correction factor according to distance. Do. This initial region is generally referred to as Rayliegh distance, and the correction factor for the initial region can be calculated as Equation 8, and z can be calculated as Equation 9.

[식 8]

[Equation 8]

[식 9]

[Equation 9]

Here, r means the distance from the transducer to the position measured by the ADCP, where r means the wavelength, and α _t means the effective radius of the ADCP ultrasonic sensor. Equation 10 is the method of obtaining the wave speed to obtain the wavelength.

[Equation 10]

Here, C means wave speed (m/s), and T means the temperature of water in degrees Celsius. Absorption correction by water means correcting that the ultrasonic reflectance gradually decreases as the ultrasonic wave is emitted due to the characteristics of water and moves away, and can be corrected by calculating a correction coefficient. Absorption correction by water requires consideration of fluid properties such as salinity and ions of water, but since the present invention is performed for a river, the absorption correction for water was considered by considering only the viscosity of water without performing additional correction. . The method of calculating the absorption correction factor (α _w ) by water is shown in Equation 11.

[식 11]

[Equation 11]

Here, f means the ultrasonic frequency (kHz) of H-ADCP, and T means the water temperature in degrees Celsius. The attenuation correction due to the similarity is to correct the amount attenuated by the similarity as the distance from the transmitter of the ultrasonic Doppler velocimetry increases, and it can be calculated using Equation 7 presented above assuming that the concentration of suspended solids in the transverse direction is constant. Through this, the finally corrected SCB (Sediment corrected backscatter) can be calculated.

7A to 7E are graphs derived from correlation coefficients by varying the upper and lower limits of the range shown in FIG. 5, respectively.

In the present invention, prior to analyzing the relationship with the measured surface-like concentration by using the corrected ultrasonic reflectance (SCB) as an index, the spatial range of the ultrasonic reflectance measured in the transverse direction is changed, and a range with a high correlation coefficient is found. The spatial averaged result is used as an index and used to analyze the relationship with the measured floating concentration.

7A to _7E are graphs for changing the spatial average range of the corrected ultrasonic reflectance (SCB) and analyzing the correlation with the measured _suspended concentration (SSC _msr ). It can be seen that the range d of FIG. 7 has the highest correlation. Here, in the range d of FIG. 7, the result of analyzing the relationship with the measured _{suspended solid} concentration (SSC _msr ) by averaging the corrected ultrasonic reflectance (SCB) is shown in FIG. 8. Here, SSC means suspension concentration, SCB means corrected ultrasonic reflectance, and β ₁ and β ₂ mean slope and intercept through linear regression analysis, respectively.

Embodiment 2

9 is a schematic block diagram for explaining a second embodiment of a method for estimating a river suspension concentration according to the present invention.

The configuration for the method for estimating the suspended dead concentration in the river according to the second embodiment includes an information input module 140, a multiple regression analysis module 150, and a suspended dead concentration estimation module 160.

Information on the ultrasonic signal reflectance and depth is received and input to the information input module 140 from the ultrasonic signal unit S, and this process is repeatedly performed. It is repeatedly performed to perform multiple regression analysis in the multiple regression analysis module 150.

The multiple regression analysis module 150 determines a regression coefficient by performing multiple regression analysis using information on the ultrasonic signal reflectance and depth input from the information input module 140.

In the suspended concentration estimation module 160, using the regression coefficient determined in the multiple regression analysis module 150, the ultrasonic signal reflectance (SCB); Depth; And a product of the ultrasonic signal reflectance (SCB) and the depth of water. Iteratively estimates the suspended solids concentration of the river with each as an independent variable. The above-described regression coefficient is an ultrasonic signal reflectance (SCB); Depth; And the product of the ultrasonic signal reflectance (SCB) and the water depth (Depth), respectively.

At this time, the suspended solid concentration estimating module 160 derives the river suspended solid concentration (SSC) by Equation 12.

<식 12>

<Equation 12>

(β ₀ , β ₁ , β ₂ , β ₃ are regression coefficients)

10 is a flow chart of a second embodiment of the method for estimating the suspended solid concentration of a river according to the present invention. The second embodiment includes steps S210 to S230.

Step S210 is a step in which the information input module 140 receives and inputs information on the ultrasonic signal reflectance and depth from the ultrasonic signal unit S.

Step S220 is a step in which a regression coefficient is determined by performing multiple regression analysis using information on the ultrasonic signal reflectance and depth repeatedly inputted in step S210 in the multiple regression analysis module 150.

Step (S230) in the suspended solids concentration estimation module 160, using the regression coefficient determined in step (S220), ultrasonic signal reflectance (SCB); Depth; And a product of the ultrasonic signal reflectance (SCB) and the depth of water. This is the step of estimating the suspended solids concentration of the river using as independent variables.

Fig. 11a is a graph showing the estimated value of suspended solids concentration and the actual measured suspended solids concentration under a condition not considering the depth of water, and Fig. 11b is a graph showing the suspended solids concentration under the condition of considering the depth of water according to the second embodiment of the present invention. It is a graph showing the estimated value and the measured suspended solid concentration.

As can be seen from the graphs a and b of Fig. 11, the result of estimating the suspended solid concentration through a simple linear regression analysis between the ultrasonic reflectance and the measured suspended solid concentration is slightly different from the measured suspended solid concentration, while Fig. 11 As shown in b, the estimated suspended solid concentration through multiple regression analysis considering water depth is very similar to the actual suspended solid concentration. That is, by using the transverse ultrasonic Doppler velocity meter according to the second embodiment of the present invention, it is possible to accurately measure the suspended solid concentration compared to the conventional method, and by using this, measurement data of the continuous suspended solid concentration may be obtained.

Third embodiment

12 is a flow chart of a third embodiment of a method for estimating a river suspension concentration according to the present invention. The third embodiment according to the present invention applies both the first and second embodiments described above. Specifically, the third embodiment includes steps (S300) to (S360).

Step (S300) is a step of checking the measured _{suspended solid} concentration (SSC _msr ).

In step S310, the ultrasonic signal filtering module 110 receives information on the ultrasonic signal reflectance from the ultrasonic signal unit S, and based on the transverse direction, which is the direction in which the ultrasonic signal is generated, the ultrasonic reflectance within a certain range. This is the step of filtering.

Step (S320), in the iterative calculation module 120, calculate the suspended _solid concentration predicted value (SSC _pdt ) using the ultrasonic reflectance in the above range, but by changing an arbitrary range within the width of the river to predict the suspended _solid concentration value by performing an operation of the repeat (SSC _pdt), a step for calculating the sediment concentration estimated value for the respective range (SSC _pdt).

Step (S330), in the range setting module 130, calculates a correlation coefficient between the estimated _suspended solids concentration in the range (SSC _pdt ) calculated in step (S320) and the measured _suspended solids concentration (SSC _msr ), and In this step, a range when the correlation coefficient is maximum is determined as a confidence range.

Step S340 is a step in which the information input module 140 receives and inputs information on the ultrasonic signal reflectance and depth within the confidence range determined in step S330 from the ultrasonic signal unit S.

Step (S350) is a multiple regression analysis module 150, by performing a multiple regression analysis using the information on the ultrasonic signal reflectance and depth within the confidence interval repeatedly input in step (S340), the regression coefficient is determined. Step.

Step (S360), in the suspended solids concentration estimation module 160, using the regression coefficient determined in step (S350), ultrasonic signal reflectance (SCB); Depth; And a product of the ultrasonic signal reflectance (SCB) and the depth of water. This is the step of estimating the suspended solids concentration of the river using as independent variables.

As described above, the third embodiment uses the ultrasonic signal reflectance (SCB) within the confidence range derived in the first embodiment as an independent variable, and at the same time, estimates the suspended concentration of the river through multiple regression analysis by considering the depth of water. Bar, it is possible to obtain a value closest to the actual _{suspended solid} concentration (SSC _msr ).

In the above, the present specification has been described with reference to the embodiments shown in the drawings so that those skilled in the art can easily understand and reproduce the present invention, but this is only exemplary, and those skilled in the art can use various modifications and equivalents from the embodiments of the present invention. It will be appreciated that embodiments are possible. Therefore, the scope of protection of the present invention should be determined by the claims.

S: ultrasonic signal unit
110: ultrasonic signal filtering module
120: iterative calculation module
130: range setting module
140: information input module
150: multiple regression analysis module
160: suspended solid concentration estimation module

Claims (9)

As a method of estimating the suspended solid concentration of a river,
An ultrasonic signal unit (S) is provided under the water surface of the river, which generates an ultrasonic signal in a transverse direction and senses a reflected signal of the generated ultrasonic signal to measure the ultrasonic signal reflectance,
(a0) confirming the measured _{suspended solid} concentration (SSC _msr ) (S100);
(a1) In the ultrasonic signal filtering module 110, information on the ultrasonic signal reflectance is transmitted from the ultrasonic signal unit S, and the ultrasonic reflectance within a certain range is filtered based on the transverse direction, which is the direction in which the ultrasonic signal is generated. The step (S110);
(a2) In the iterative calculation module 120, the estimated _suspended solids concentration (SSC _pdt ) is calculated using the ultrasonic reflectance in the above range, but by changing an arbitrary range within the width of the river, the estimated _suspended solids concentration ( by performing the calculation of the SSC _pdt) repeating the step of calculating the sediment concentration estimated value for the respective range (SSC _pdt) (S120); And
(a3) In the range setting module 130, the correlation coefficient between the estimated _suspended solids concentration (SSC _pdt ) and the measured _suspended solids concentration (SSC _msr ) in each of the ranges calculated in step (a2) (S120) And determining the range when the correlation coefficient is the maximum as a confidence range, and determining an estimated suspended _solid concentration (SSC _pdt ) in the confidence range as an estimated total suspended _solid concentration (SSC) in the river (S130 ); Containing,
A method of estimating the suspended concentration of rivers.
The method of claim 1,
The (a1) step (S110) corrects the ultrasonic reflectance (SCB) within the range,
(a11) performing correction for beam spreading (S111);
(a12) performing correction for absorption by water (S112); And
(a13) performing attenuation correction by the floating yarn (S113); Containing,
A method of estimating the suspended concentration of rivers.
The method of claim 1,
In the step (a2) (S120),
The expected value of suspended solids concentration (SSC _pdt ) in the above range is,
The average ultrasonic reflectance (SCB _avg ) in the above range is used as an independent variable and calculated through linear regression analysis, but the estimated suspended _solid concentration (SSC _pdt ) is derived by the following Equation 1,

<Equation 1>
A method of estimating the suspended concentration of rivers.
The method of claim 1,
The (a2) step (S120),
By changing the upper or lower limit of the range to repeatedly perform the calculation of the expected _suspended solids concentration (SSC _pdt ),
A method of estimating the suspended concentration of rivers.
As a method of estimating the suspended solid concentration of a river,
An ultrasonic signal unit (S) for generating an ultrasonic signal in the transverse direction under the water surface of the river, measuring the ultrasonic signal reflectance by recognizing the reflected signal of the generated ultrasonic signal, and measuring the water depth is provided,
(b1) a step in which the information input module 140 receives and inputs information on the ultrasonic signal reflectance and water depth from the ultrasonic signal unit S (S210);
(b2) In the multiple regression analysis module 150, the step of determining a regression coefficient by performing multiple regression analysis using information on the ultrasonic signal reflectance and depth repeatedly inputted in step (b1) (S210) ( S220); And
(b3) In the suspended dead concentration estimation module 160, the regression coefficient determined in step (b2) (S220) is used, and
Ultrasonic signal reflectance (SCB);
Depth; And
Product of ultrasonic signal reflectance (SCB) and depth (Depth); Estimating the suspended solid concentration of the river by using as independent variables (S230); Containing,
A method of estimating the suspended concentration of rivers.
The method of claim 5,
The (b3) step (S230) is to derive the river suspended solid concentration (SSC) by the following equation,

<Equation 2>
(β ₀ , β ₁ , β ₂ , β ₃ are regression coefficients)

A method of estimating the suspended concentration of rivers.
As a method of estimating the suspended solid concentration of a river,
An ultrasonic signal unit (S) is provided under the water surface of the river, which generates an ultrasonic signal in the transverse direction, recognizes the reflected signal of the generated ultrasonic signal, and measures the ultrasonic signal reflectance
(c0) confirming the measured _{suspended solid} concentration (SSC _msr ) (S300);
(c1) In the ultrasonic signal filtering module 110, information on the ultrasonic signal reflectance is transmitted from the ultrasonic signal unit S, and the ultrasonic reflectance within a certain range is filtered based on the transverse direction, which is the direction in which the ultrasonic signal is generated. A step (S310);
(c2) In the iterative calculation module 120, the estimated _suspended solids concentration (SSC _pdt ) is calculated using the ultrasonic reflectance in the above range, but by changing an arbitrary range within the width of the river, the estimated _suspended solids concentration ( by performing the calculation of the SSC _pdt) repeating the step of calculating the sediment concentration estimated value for the respective range (SSC _pdt) (S320);
(c3) In the range setting module 130, a correlation coefficient between the estimated _{suspended solid} concentration (SSC _pdt ) and the measured _{suspended solid} concentration (SSC _msr ) in the range calculated in the (c2) step (S320) Calculating, and determining a range when the correlation coefficient is maximum as a confidence range (S330);
(c4) The information input module 140 receives and inputs information on the ultrasonic signal reflectance and depth within the confidence range determined in step (c3) (S330) from the ultrasonic signal unit (S). S340);
(c5) In the multiple regression analysis module 150, by performing multiple regression analysis using information on the ultrasonic signal reflectance and depth in the confidence interval repeatedly inputted in step (c4) (S340), the regression coefficient Determining step (S350); And
(c6) In the suspended dead concentration estimation module 160, the regression coefficient determined in step (c5) (S350) is used, and
Ultrasonic signal reflectance (SCB);
Depth; And
Product of ultrasonic signal reflectance (SCB) and depth (Depth); Estimating the suspended solids concentration of the river using as independent variables (S360); Containing,
A method of estimating the suspended concentration of rivers.
The method according to any one of claims 1 to 7,
The ultrasonic signal unit S is an ultrasonic Doppler flow meter,
A method of estimating the suspended concentration of rivers.
The method according to any one of claims 5 to 7,
The ultrasonic signal unit (S) is provided with a pressure sensor, for deriving the depth of the river using the water pressure measured by the pressure sensor,
A method of estimating the suspended concentration of rivers.

Images