KR20190013108A - System and method for assessing wall thinning occurrence - Google Patents

Abstract

According to various embodiments, disclosed are a method and a system for determining wall thinning. The method for determining wall thinning comprises the following steps of: acquiring a first measurement value which is a measurement value with respect to thickness of a pipe measured at a first time and a second measurement value which is a measurement value with respect to thickness of the pipe measured at a second time after the first time; calculating a deviation value based on the first measurement value and the second measurement value; and determining whether or not local wall thinning occurs in the pipe by analyzing a statistical property with respect to the deviation value.

Description

[0001] The present invention relates to a thinning discrimination system and method,

The present invention relates to a system and method for discriminating thinning, and more particularly, to a method and system for discriminating thinning by using thickness measurement data of a pipe or a pressure vessel such as pipes and fittings, And to a method and system.

It is necessary to comprehensively manage the phenomenon of thinning (reduction in thickness) caused by corrosion, flow accelerated corrosion, erosion, and erosion caused in pipes or pressure vessels of power plants and general industrial facilities. In industry, pipes or pressure vessels that are expected to decrease in thickness due to thinning are periodically measured by nondestructive testing and the degree of progress of thinning is determined or predicted.

In addition to the production deviation inevitably occurring at the time of manufacturing the piping and the pressure vessel, the data measured at the actual site includes the measurement deviation. Existing evaluation methods do not reflect these deviations, so they are overestimating or underestimating thinning, and can not analyze the characteristics of thinning.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a thinning discrimination system capable of accurately determining the occurrence of thinning in a pipe by statistically analyzing the results of thickness measurements on many pipes, Let us provide a method.

A thinning determination method according to one aspect of the present invention is a method for determining a thickness of a pipe measured at a first time and a first measurement value at a second time after the first time, Calculating a deviation value based on the first measured value and the second measured value, and analyzing statistical characteristics of the deviation value to determine the occurrence of localized thinning of the pipe Or not.

According to an example of the thinning discrimination method, the method further includes extracting the grid point having the deviation value equal to or larger than a preset upper limit value, and obtaining coordinate information corresponding to the extracted grid point.

According to another example of the thinning discrimination method, the method further comprises calculating a variance value between the extracted grid points based on the obtained coordinate information.

According to another example of the thinning determination method, the step of determining the local thinning of the pipe may include comparing the preset reference value and the calculated dispersion value with each other, and when the calculated dispersion value is smaller than a preset reference value, And determining that localized thinning has occurred in one region of the pipe.

According to another example of the thinning discrimination method, the method further comprises estimating a position where the thinning of the pipe occurs based on the coordinate information corresponding to each of the extracted grid points.

According to another example of the thinning discrimination method, the step of classifying the plurality of grid points into a plurality of groups is further included.

According to another example of the thinning determination method, in the grouping into the plurality of groups, the plurality of groups are divided into a plurality of groups such that the same number of grid points are included.

According to another example of the thinning discrimination method, the step of discriminating the thinning state of the pipe includes a step of analyzing statistical characteristics such as a sum, an average and a variance between the deviation values of the lattice points in the group, And calculating a test statistic for significant differences between the plurality of groups.

According to another example of the thinning discrimination method, the step of determining the thinning state of the pipe comprises the steps of: comparing the test statistic with a reference statistic at a predetermined level of significance; and comparing the test statistic with a reference statistic , It is determined that localized thinning has occurred in one region of the pipe.

According to another example of the thinning discrimination method, the number of lattice points, which is the number of lattice points having a deviation value equal to or larger than a preset upper limit value for each of the classified groups, and the number of lattice points having a deviation value less than the predetermined upper limit value, .

According to another example of the thinning discrimination method, the step of discriminating the thinning state of the pipe includes a step of calculating a test statistic for a significant difference between a plurality of groups by comparing the thinning water and the unterminated vegetation among the groups And further comprising:

The thinning discrimination system according to another aspect of the present invention includes a measuring unit for measuring the thickness of the pipe at each of the plurality of lattice points, a measuring unit for measuring the thickness of the pipe at each of the plurality of lattice points measured from the first time, And a second measurement value that is a measurement value of the thickness of the pipe measured by the measurement unit at each of the plurality of grid points from a second time after the first time to the first measurement value, A deviation value calculation unit for calculating a deviation value at each of the lattice points based on the first measured value and the second measured value; and a deviation value calculation unit for calculating, based on the statistical characteristic of the deviation value, And a thinning discrimination section for discriminating whether thinning has occurred or not.

According to an example of the thinning discrimination system, the apparatus further comprises a lattice point extracting unit for extracting the lattice points having the calculated deviation value equal to or larger than the preset upper limit value, and the lattice points are coordinate information Is set.

According to another example of the thinning discrimination system, the thinning discrimination unit obtains the coordinate information corresponding to the extracted lattice points, and calculates a variance value between the extracted lattice points.

According to another example of the thinning discrimination system, the thinning discrimination unit compares the dispersion value with a preset reference value, and when the dispersion value is smaller than the predetermined reference value, local thinning occurs in the pipe corresponding to the one area .

According to another example of the thinning discrimination system, the thinning discrimination unit estimates the position of the pipe where the local thinning occurs, based on the obtained coordinate information.

According to another example of the thinning discrimination system, the thinning discrimination system further includes a group classifying unit for classifying the plurality of grid points into a plurality of groups based on the coordinate information.

According to another example of the thinning discrimination system, the thinning discrimination unit analyzes statistical characteristics such as sum, average and variance between the deviation values of the grid points in the respective groups, and calculates a test statistic for a significant difference between the plurality of groups .

According to another example of the thinning discrimination system, the thinning discrimination unit discriminates that local thinning has occurred in one region of the pipe if the test statistic is less than a reference statistic at a preset significance level.

According to another example of the thinning discrimination system, the number of lattice points, which is the number of lattice points having a deviation value equal to or larger than a preset upper limit value for each of the classified groups, and the number of lattice points having a deviation value less than the predetermined upper limit value, And a discrete-time variable detecting unit.

According to another example of the thinning discrimination system, the thinning discrimination unit calculates a test statistic for a significant difference between a plurality of groups based on the declining water and the unstressed water in each of the groups.

According to another example of the thinning discrimination system, if the calculated test statistic has a value lower than a reference statistic at a predetermined significance level, the thinning discrimination unit discriminates that local thinning has occurred in one region of the pipeline .

The thinning discrimination system and method according to various embodiments can analyze the thickness measurement results of a number of pipes by a statistical method to promptly determine whether thinning occurs in the pipe, and can accurately determine the position of the pipe where the thinning occurs. This makes it possible to accurately analyze the thinning state of the piping on the installation, and it is possible to replace the piping where the thinning occurs at an appropriate time according to the analysis result, thereby improving the stability and economical efficiency of the piping system.

FIG. 1 is a view illustrating a process of collecting information on thickness of one region of a pipe according to an embodiment of the present invention. FIG.
FIG. 2 is a schematic view illustrating an internal structure of a thinning discrimination system according to an embodiment of the present invention. Referring to FIG.
3A shows an exemplary table that summarizes the first measurement values stored by the data collection unit according to an embodiment of the present invention.
FIG. 3B shows an exemplary table that summarizes the second measurement values of the data collection unit according to an embodiment of the present invention.
FIG. 3C shows an exemplary table that summarizes the deviation values calculated by the deviation value calculating section in one embodiment of the present invention.
FIGS. 4A and 4B are views for explaining a method of calculating a variance value using coordinate information of lattice points according to an embodiment of the present invention.
5A and 5B illustrate a table for explaining a method of obtaining a group-specific test statistic by the thinning discrimination system according to an embodiment of the present invention.
6A and 6B are views for explaining a method for determining whether local thinning occurs in one region of a piping according to another embodiment of the present invention.
FIG. 7 is a flowchart illustrating a method for determining whether a thinning of a region of a pipe is to be performed by the thinning discrimination system according to an embodiment of the present invention.
8 is a flowchart illustrating a method for determining whether a thinning of a region of a pipe is to be performed by a thinning discrimination system according to another embodiment of the present invention.
9 is a flowchart illustrating a method for determining whether a thinning of a region of a pipe is to be performed by the thinning discrimination system according to another embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention and methods of achieving them will be apparent with reference to the embodiments described in detail below with reference to the drawings. However, the present invention is not limited to the embodiments described below, but may be implemented in various forms. In the following embodiments, the terms first, second, and the like are used for the purpose of distinguishing one element from another element, not the limitative meaning. Also, the singular expressions include plural expressions unless the context clearly dictates otherwise. Also, the terms include or comprise mean that a feature, or element, described in the specification is present, and does not preclude the possibility that at least one other feature or element may be added. Also, in the drawings, for convenience of explanation, the components may be exaggerated or reduced in size. For example, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and thus the present invention is not necessarily limited to those shown in the drawings.

FIG. 1 is a view illustrating a process of collecting information on thickness of one region of a pipe according to an embodiment of the present invention. FIG.

Referring to FIG. 1, a plurality of grid points are predefined in one area of a pipe 10, and the thinning discrimination system 100 includes a measuring unit 110 and a data collecting unit 120.

The piping 10 is intended to transport liquids, gases, powders, and the like, and includes pipes and fittings. The pipe provides a path through which the liquid, gas, powder, and the like are moved, and the fitting flows between the pipe and the pipe. Fittings are the elbow used to change the direction of the pipe depending on the purpose of connecting the pipe to the pipe, the reducer used for connection between the pipe, the return, the miter and the pipe having different diameters, the flange connecting pipes . For convenience of explanation, the piping 10 including pipes and fittings will be mainly described below.

A plurality of grid points are defined in one region of the pipe 10. A plurality of lattice points may be displayed on the pipeline 10 with respect to the other region, and the one region and the other regions may be selected as a region where the thinning occurs relatively well. The piping 10 is judged whether or not localized thinning is independent of the other regions with respect to the one region and the thinning discrimination method of the pipe 10 for the one region is applied as it is. A method for determining whether or not localized thinning has occurred in one region of the pipe 10, which is an area for the purpose of determining whether or not localized thinning has occurred, will be mainly described.

The plurality of lattice points are located on a grid pattern spaced apart at a predetermined interval. The number and arrangement of the plurality of grid points are not limited to those shown in FIG. 1 and may be variously arranged and numbered, and the spirit of the present invention is not limited to the number and arrangement of the plurality of grid points. For example, a plurality of lattice points may be arranged by 12 by 12, 10 by 2, 100 by 200, and so on.

The plurality of lattice points are spaced apart from each other by a certain distance between adjacent lattice points, and the respective distances may have different values or may have the same value. Hereinafter, for convenience of explanation, it is assumed that the plurality of lattice points are arranged on a lattice pattern including a lattice spaced by the same distance as adjacent lattice points, that is, a lattice spaced at regular intervals. The plurality of lattice points may be directly displayed on a region of the pipe 10 by a paint or the like, projected by an external projector, and displayed. If the range of the present invention is the display method of the plurality of lattice points .

The thinning discrimination system 100 can measure the thickness of the pipe 10 through the measuring unit 110 for each grid point displayed on the pipe 10. [ The thinning discrimination system measures the thickness of the pipe 10 at every point where the plurality of grid points are displayed and information on the thickness of the measured pipe 10 is stored in the data collection unit 120.

The thinning discrimination system 100 stores the thickness of the pipe 10 measured corresponding to the coordinate information set for each of the plurality of grid points. The coordinate information may be set according to the arrangement order of the plurality of grid points displayed in one area of the pipe 10, and each of the plurality of grid points may be set to a position on one area of the displayed pipe 10, The correspondence relationship between coordinate information is also set in advance. That is, it is possible to specify a grid point arranged at a predetermined position among the plurality of grid points through the coordinate information, and through the corresponding relationship between the coordinate information and the position on one region of the pipe 10, The position of the point where the grid point is displayed on the region of the pipe 10 can be also known.

For example, the coordinate information is set to information on the order in which the plurality of grid points are arranged in the circumferential direction of the pipe 10 and the position in the axial direction of the pipe 10. That is, as shown in FIG. 1, the positions of the grating points arranged in the circumferential direction from the first point A1 of the end of one region of the pipe 10 are assigned in order of B, C, and D, The coordinate information for each lattice point can be set by assigning the positions of the lattice points arranged in the axial direction of the pipe 10 from the point A1 to the lattice points in the order of 2, Information about a grid point having coordinate information of the first point A1 is displayed at a certain point on one area of the pipe 10.

The measuring unit 110 can measure the thickness of pipes and fittings included in the pipe 10 by a non-destructive method. The measuring unit 110 may include an electromagnetic type for measuring a thickness using a magnetic body according to a measuring method, a radiation type for measuring a thickness using radiation, and an ultrasonic measuring apparatus for measuring using ultrasonic waves. The measuring unit 110 measures the thickness of the pipe 10 at each point where the plurality of grid points are displayed.

The data collection unit 120 includes a memory for receiving and storing information on the thicknesses of pipes and fittings measured by the measurement unit 110. Magnetic storage media, or flash storage media, although the scope of the invention is not so limited. The data collecting unit 120 is electrically connected to the measuring unit 110 to directly receive information on the thickness of the pipe 10 including the measured pipe and fittings or to measure the measured value by the measuring unit 110 A value may be entered.

The data collection unit 120 stores measured values of the thickness of the pipe 10 measured by the measurement unit 110 in association with the grid points. That is, the data collection unit 120 stores the thickness of the pipe 10 measured by the measurement unit 110 in a table corresponding to each of the plurality of grid points. In addition, the data collecting unit 120 previously stores the coordinate information corresponding to the lattice point. The data collection unit 120 previously stores the coordinate information corresponding to each of the lattice points based on the arrangement order of the lattice points. For example, lattice points can be displayed along the circumferential direction of the pipe 10 and the axial direction of the pipe 10. In this case, the coordinate information is set in the order of A, B, and C in the order arranged in the circumferential direction with respect to the first point A1, and the coordinate information is set in the order of 1, 2, Respectively. In this case, the data collecting unit 120 stores the coordinate information corresponding to the lattice points of the first point A1 as A1 and the lattice point of each point according to the arrangement order in the circumferential direction with respect to the first point A1 The coordinate information corresponding to B1. C1, and the coordinate information corresponding to the lattice point of each point is stored as A2 and A3 according to the order of arrangement in the axial direction. On the other hand, the coordinate information can be expressed in 1, 2, and 3 dimensions, and will be described below assuming a two-dimensional coordinate for convenience of explanation.

According to one embodiment, the thinning discrimination system 100 collects information on the thickness of the pipe 10 at each of the plurality of grid points from a first time and calculates a thickness of the pipe 10 at a first time The information on the thickness of the pipe 10 can be repeatedly measured at the second time after the measurement is completed. The second time may be set in consideration of the degree of progress of the thinning of the pipe 10. For example, if the expected time for the pipe 10 to decrease by 1% is 6 months, the second time may be set to 6 months from the first time. On the other hand, the thickness of the pipe 10 measured at each of the plurality of grid points at the first time is defined as a first measurement value, and the thickness of the pipe 10 measured at each of the plurality of grid points at the second time The thickness is defined as the second measured value.

Specifically, the measuring unit 110 measures the thickness of the pipe 10 at each lattice point at a point where the plurality of lattice points are displayed at the first time. The data collecting unit 120 stores measured values of the thickness of the pipe 10 measured by the measuring unit 110 in association with the respective lattice points. For example, when the measuring unit 110 measures a thickness of 3 mm at the lattice point of the first point A1, a thickness of 2 mm at the lattice point of the second point A2, and a thickness of 2 mm at the lattice point of the third point A3, The lattice point of the first point A1 is 3 mm, the lattice point of the second point A2 is 2 mm and the lattice point of the third point A3 is 2 mm And collects and stores the thickness of the pipe 10 measured by the measuring unit 110 in correspondence with the grid points at each point. On the other hand, when the measurement of the thickness of the pipe 10 with respect to the plurality of grid points is completed, the data collecting unit 120 collects the collection information on the thickness of the pipe 10 corresponding to the plurality of grid points, Values are stored as data.

Thereafter, the thinning determination system 100 re-measures the thickness of the pipe 10 at each of the plurality of grid points at a second time after the first measured value is stored. The plurality of lattice points measured by the measuring unit 110 at the first time and the second time are the same lattice points. That is, the measuring unit 110 re-measures the thickness of the pipe 10 at a plurality of grid points at the same position as measured at the first time, at the second time. The data collecting unit 120 stores the measured values of the thickness of the pipe 10 measured by the measuring unit 110 as a second measured value at the second time

FIG. 2 is a schematic view illustrating an internal structure of a thinning discrimination system according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 2, the thinning discrimination system 100 includes a measuring unit 110, a data collecting unit 120, a deviation value calculating unit 130, a lattice point extracting unit 140, a grouping unit 150, A variable detecting unit 160 and a thinning judging unit 170.

The measuring unit 110 can measure the thickness of the pipe 10 including pipes and fittings by a non-destructive method. The measuring unit 110 may include an electromagnetic type for measuring a thickness using a magnetic body according to a measuring method, a radiation type for measuring a thickness using radiation, and an ultrasonic measuring apparatus for measuring using ultrasonic waves. The measuring unit 110 measures the thickness of the pipe 10 at each point indicated by the lattice points, as described with reference to Fig. The thicknesses of the pipe 10 measured by the measuring unit 110 for each of a plurality of grid points are transmitted to the data collecting unit 120.

The data collecting unit 120 stores the thickness of the pipe 10 delivered by the measuring unit 110 in correspondence with each lattice point. For example, the data collecting unit 120 may acquire the data of the lattice points of the first point (A1), the second point (A2), and the first point (B1) And stores the measurement value transmitted by the measurement unit 110 in correspondence with the coordinate information of the point.

According to one embodiment, the data collection unit 120 stores the thicknesses of the pipe 10 corresponding to a plurality of grid points at a first time as a first measurement value, And the thicknesses of the pipe 10 corresponding to the plurality of grid points are divided into a second measurement value and stored.

When the storing of the information about the first measurement value and the second measurement value is completed, the thinning discrimination system 100 determines the thinning degree for one region of the pipe 10 based on the first measurement value and the second measurement value, Start to determine the state of thinning.

The deviation value calculation unit 130 calculates a deviation value, which is a variation in thickness of the pipe 10 at a point where each lattice point is displayed based on the first measured value and the second measured value. The deviation value calculation unit 130 may calculate the deviation value by calculating a difference value between the first measured value and the second measured value at any one of the grid points. For example, when the first measured value is 2 mm at the lattice point of the first point A1 and the second measured value is 1.8 mm, the deviation value calculation unit 130 calculates the deviation value at the lattice point of the first point A1 The deviation value for 0.2 mm is calculated. In this way, the deviation value calculation unit 130 can calculate a deviation value for each of a plurality of lattice points. The deviation value calculation unit 130 stores the deviation values in association with each of a plurality of grid points in the same manner as the data collection unit 120.

That is, the deviation value calculation unit 130 measures a deviation value which is a variation amount of the thickness of the pipe 10 at a point where each lattice point is displayed after a predetermined time has elapsed based on the first measured value and the second measured value . That is, the deviation value calculating unit calculates information on how much the thickness of the pipe 10 measured at each of the plurality of grid points displayed on the pipe 10 has changed after the passage of time from the first time to the second time Can be calculated.

The lattice point extracting unit 140 may extract predetermined lattice points from a plurality of lattice points. The lattice point extracting unit 140 compares a deviation value corresponding to each of the plurality of lattice points with a preset upper limit value and extracts lattice points having a deviation value equal to or greater than the predetermined upper limit value. At this time, the predetermined upper limit value is set based on the deviation values. The preset upper limit value is set to extract a point at which the pipe 10 is largely thinned, and may be set to a value higher than the deviation values. For example, when the deviation values for the plurality of lattice points are 0.1, 0.11, 0.1, 0.2, 0.4, 0.42, 0.2, 0.2, 0.6, 0.21, 0.32, 0.65, It is possible to set the deviation value corresponding to the pro as the preset upper limit value. In this case, the preset upper limit value may be set to 0.42 corresponding to the upper 30% of the deviation values. At this time, the lattice point extracting unit 140 extracts lattice points having a deviation value of 0.42 or more.

According to another embodiment, the lattice point extracting unit 140 may be configured to extract a grid point by a predetermined number. Specifically, the lattice point extracting unit 140 arranges the deviation values in order of magnitude, and extracts the deviation values by the predetermined number in order from a large magnitude value. For example, when the deviation values are listed in order of magnitude, 0.4, 0.42, 0.1, 0.1, 0.2, 0.2, 0.2, , 0.6, and 0.65, respectively.

The group classification unit 150 classifies a plurality of grid points into a plurality of groups based on the coordinate information. At this time, the group classifying unit 150 classifies the adjacent grid points into one group and includes the same number of grid points among the groups. For example, the group classifying unit 150 classifies the plurality of grid points into a plurality of groups in units of 2 by 2, 3 by 3, 4 by 4, etc. based on the coordinate information.

The discrete variable detecting unit 160 can detect the discretized information from the deviation value of the group. Specifically, the discrete variable detecting unit 160 detects the number of lattice points whose deviation values of the lattice points in each group are equal to or greater than a preset upper limit value. That is, the discrete variable detecting unit 160 detects the number of lattice points having a deviation value equal to or greater than the preset upper limit value and the number of lattice points having a deviation value less than the predetermined upper limit value for each group. At this time, the predetermined upper limit value is set to a value corresponding to the value set in the lattice point extracting unit 140.

The thinning discrimination unit 170 may determine whether local thinning occurs in one region of the pipe 10 by calculating the variance of the grid points extracted by the grid point extracting unit 140, A test statistic is obtained based on the deviation values between a plurality of groups or a test statistic based on the gravy and unstressed gravity of each group detected by the discrete variable detection unit 160, Can be distinguished.

According to one embodiment, the thinning determination unit 170 can determine whether localized thinning occurs in one region of the pipe 10 based on the coordinate information of the grid points extracted by the grid point extraction unit 140. The thinning discrimination unit 170 obtains coordinate information of the lattice points extracted from the lattice points. The thinning determination unit 170 calculates a variance value based on the coordinate information of the extracted grid points. The thinning determination unit 170 compares the calculated dispersion value with a preset reference value. When the calculated variance value is equal to or greater than a preset reference value, it is determined that localized thinning does not occur in one region of the pipe 10. If the calculated variance value is less than a preset reference value, the thinning discrimination unit 170 ) Is considered to have caused localized thinning in one region.

The predetermined reference value is a value for variance serving as a criterion for whether or not the extracted grid points are located in close proximity to each other. The preset reference value may be preset in advance based on a probability distribution. More specifically, when extracting a plurality of samples having the plurality of grid points and the same coordinate range and randomly selecting the same number of the extracted grid points, a probability distribution with respect to the variance values of the samples can be obtained have. The probability that the randomly extracted lattice points are concentrated in each other is considerably lower than the case where the lattice points are uniformly distributed to each other. In consideration of this point, the thinning discrimination unit 170 can predict a dispersion value that can be estimated as a density of the plurality of lattice points, and can set the predicted dispersion value to the preset reference value. For example, the predetermined reference value may be set to a variance value having a probability of 1% to 10% in the probability distribution. The predetermined reference value may vary according to the number and arrangement of the plurality of lattice points.

According to another embodiment, the thinning discrimination unit 170 can determine whether localized thinning has occurred in one region of the pipe 10 by statistical analysis using the deviation values of each group classified by the group classifying unit 150. [ The thinning determination unit 170 obtains statistical characteristics such as sum, average, and variance of deviation values in each group, and calculates the dispersion characteristics among the groups based on the statistical characteristics. The thinning determination unit 170 determines whether there is a significant difference (F) between the groups based on the dispersion characteristics. For example, the thinning determination unit 170 calculates a test statistic based on a significant difference (F) of each group, and compares the calculated test statistic with a reference statistic at a predetermined significance level. If the test statistic is greater than or equal to the reference statistic at the predetermined significance level, the thinning judgment unit 170 judges that local thinning does not occur in one region of the pipeline 10, If it is less than the reference statistic, it is determined that localized thinning has occurred in one region of the pipe 10. Meanwhile, the reference statistic at the predetermined significance level is set to a value between 0.01 and 0.05. On the other hand, it is possible to use the variance analysis according to the one-way method as a method of calculating a significant difference and a significant probability between such groups.

For example, the test statistic is a probability variable defined in the sample space of the experiment, with probability that the extreme result is actually observed, assuming that the null hypothesis is correct in the statistical hypothesis test, And if the test statistic is higher than the significance level, the null hypothesis is not rejected, so that it is determined that the local thinning does not occur in the pipe 10, If the test statistic is less than the significance level, the null hypothesis is rejected and it is determined that localized thinning has occurred in the pipe 10.

According to another embodiment, the thinning discrimination unit 170 can determine whether the pipe 10 is localized by performing a statistical analysis based on the decolored water and the non-sensitized water discretized by the discrete variable detection unit 160. Specifically, the thinning discrimination unit 170 statistically analyzes whether there is a significant difference between the groups in which the sweetened water and the non-treated water are grouped. The thinning discrimination unit 170 can calculate a statistically significant difference and a test statistic between the groups of sweetened water and non-sensitive water. If the calculated test statistic is smaller than the reference statistic at a predetermined significance level, the thinning judging unit 170 may determine that localized thinning has occurred in the pipeline 10. The reference statistic at the predetermined significance level is set to a value between 0.01 and 0.05.

For example, if the test statistic is higher than the above-mentioned significance level, the null hypothesis is not rejected, so that the local thinning of the pipe (10) If the test statistic is lower than the significance level, the null hypothesis is rejected and it is determined that localized thinning has occurred in the pipe 10. The chi-squared distribution can be used to calculate these test statistics.

FIG. 3A shows an exemplary table in which first measured values stored by the data collecting unit according to an embodiment of the present invention are summarized. FIG. FIG. 3C shows an exemplary table in which deviation values calculated by the deviation value calculating section are summarized in an embodiment of the present invention.

Referring to FIGS. 3A and 3B, Tables 1 and 2 are tables in which the first measurement value and the second measurement value measured at each grid point indicated on the pipe 10 by 12 by 12 are summarized.

The data collecting unit 120 receives the information about the thickness of the pipe 10 at the position where the lattice points are displayed at the first time, from the measuring unit 110, and stores the information as the first measured value. The data collection unit 120 stores the measured thickness of the pipe 10 as a first measurement value in association with the position information of the grid point measured by the measurement unit 110. Similarly, the data collection unit 120 collects information on the thickness of the re-measured pipe 10 at a point where each lattice point is indicated at a second time after the first time, and stores the collected information as the second measured value.

Table 1 is a table arranged such that the first measured values stored by the data collection unit correspond to the coordinate information of each lattice point. As described with reference to FIG. 1, in Table 1, the coordinate values according to the order in the circumferential direction of the pipe 10 are taken as the horizontal axis, and the coordinate values according to the order arranged in the axial direction of the pipe 10 are shown as vertical axis do. For example, the thickness of the pipe 10 corresponding to B3 in Table 1 is 0.751 in relation to the thickness of the pipe 10 measured at a grid point located second in the circumferential direction and third in the axial direction.

Table 2 is arranged such that the second measured values correspond to the coordinate information as in Table 1 above.

On the other hand, as described above, the second measured value is obtained by dividing the thickness of the pipe 10 re-measured for each of the same grid points again at a second time after the first time after the first measured value is measured, (120) collects and stores the measured value separately from the first measured value. That is, the lattice points having the coordinate information of B3 in Table 1 are the same lattice points as the lattice points having the coordinate information of B3 in Table 2.

Referring to FIG. 3C, Table 3 is a table summarizing the difference between the first measured value and the second measured value at each lattice point. When a time elapses from the first point of view to the second point of time, And information on a deviation value which is a variation amount of the thickness of the pipe 10 measured.

Table 3 is a table in which the deviation values calculated by the deviation value calculation unit 130 are arranged according to the coordinate information. In other words, Table 3 shows the coordinate values in the ordinate direction of the pipe 10 and the ordinate axis as the coordinate values in the order arranged in the circumferential direction of the pipe 10 as shown in the first and second tables Value. In this case, in Table 3, when the deviation value has a negative value, the thickness increases. When the deviation value has a negative value, the thickness of the pipe 10 decreases.

The deviation values may be used to extract a point at which the thinning occurs, or may be used as a value for analyzing the statistical characteristics of the thinning determination unit 170, which will be described later.

FIGS. 4A and 4B are views for explaining a method of calculating a variance value using coordinate information of lattice points according to an embodiment of the present invention.

Referring to FIG. 4A, Table 4 summarizes the deviation values calculated based on the first measured value of Table 1 shown in FIG. 3A and the measured value of the second measured result of Table 2, and Table 5 shows a grid point extraction unit 140 Is the table that provides the information corresponding to the coordinate information of the grid points extracted.

Table 4 shows shaded squares corresponding to the grid points extracted by the grid point extracting unit 140. The lattice point extraction unit 140 may set 0.008, which is a value corresponding to the upper limit 10% of the deviation value, to a predetermined upper limit value when the deviation values in Table 4 are input. In this case, The grid points having coordinate information of A1, B1, D1, G2, C4, F6, I7, I8, D9, G9, E11, J11, A12, E12 and F12 are extracted.

Table 5 is a table showing coordinate values converted into corresponding numbers in order to obtain the variance values of the extracted grid points. That is, assuming that each lattice point is separated by the same distance as adjacent lattice points as described above, A, B, C, D, etc. can be converted into corresponding numbers 1, 2, 3, 4, .

According to one embodiment, when the coordinate information of the extracted grid points is input as shown in Table 5, the thinning determination unit 170 can obtain a variance value that is a degree of separation between the grid points extracted based on the coordinate information . The thinning determination unit 170 may calculate a variance value of the calculated density of the grid points based on the coordinate information. The thinning determining unit 170 can obtain a variance value based on the coordinate information by various methods.

For example, the thinning discrimination unit 170 may calculate the variance value by dividing the coordinate information on the two-dimensional plane by the variance value on the vertical axis and the variance value on the horizontal axis. Specifically, when the thinning discrimination unit 170 calculates the variance value in Table 5, the thinning discrimination unit 170 sets the thinning discrimination unit 170 to 1, 1, 1, 3, 4, 6, 7, 8, 9, 9, , 17,838 can be calculated from the coordinate values of the vertical axis of 12, 12, 12, and 1, 2, 4, 7, 3, 6, 9, 9, 4, 7, 5, 10, 1, 5, 6 The variance value of 8.057 can be calculated from the abscissa axis coordinate value.

Meanwhile, the method of obtaining the variance value, which is one example, is a method presented for convenience of explanation. Alternatively, the variance value corresponding to two dimensions can be calculated by considering the two-dimensional coordinate information together, The idea of the present invention is not limited by a specific method for obtaining the dispersion value.

Referring to FIG. 4B, Table 6 is a table summarizing the deviation values based on the first measured value and the second measured value calculated in one region and the other region of the pipe 10 obtained in the above-described Table 4 , And Table 7 is a table for providing information on the lattice points having the upper limit value or more set in Table 6 by the lattice point extracting unit 140.

Table 6 is a table in which cells corresponding to grid points extracted by the grid point extracting unit 140 are shaded. The lattice point extraction unit 140 may set 0.035 corresponding to the upper 10% of the deviation values to a preset upper limit value when the deviation values in Table 6 are input. In this case, The grid points having coordinate information of E7, F7, H7, E8, F8, G8, H8, F9, G9, H9, F10, G10, H10, E11,

Table 7 is a table in which coordinate values of characters are converted into corresponding numbers in order to obtain the variance values of grid points indicated in Table 6. That is, as described above, it is possible to convert A, B, C, D, etc. into 1, 2, 3, 4, etc., assuming that each lattice point is spaced at the same distance as adjacent lattice points.

According to one embodiment, the thinning discrimination unit 170 can obtain the variance of the axial coordinate (vertical axis) and the variance of the circumferential coordinate (horizontal axis). In the case of calculating the variance value in Table 7, the thinning discrimination unit 170 calculates the deceleration values of 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 11, And a variance value of 1.381 from the abscissa of 5, 6, 8, 5, 6, 7, 8, 6.7, 8, 6, 7, 8, 5, Can be calculated.

According to one embodiment, the thinning determination unit 170 can determine whether localized thinning has occurred in one region of the pipe 10 based on the dispersion value of the extracted grid points. For example, when the variance value (that is, a preset reference value) in which 15 grid points among the grid points arranged at 12 by 12 are assumed to be crowded is set to 3, the thinning discrimination unit 170 calculates the difference In one region of the piping 10 having a value of less than 3, it can be determined that no localized thinning has occurred, and in another region of the pipe having the deviation value shown in Table 6, It can be determined that local thinning has occurred.

According to one embodiment, when the local thinning occurs in one area of the pipe 10, the thinning determining unit 170 can provide a position on the pipe 10 where the local thinning occurs. For example, for a pipe having a deviation value in Table 6, the thinning judgment unit 170 judges whether or not the local thinning has occurred, E7, F7, H7, E8, F8, G8, H8, F9, G9, H9, F10, G10, H10, E11, and H11 and positional information on the pipe 10 corresponding to the coordinate information can be provided to an external display device or the like.

Thus, the thinning discrimination system 100 extracts lattice points having deviation values of a plurality of lattice points equal to or greater than a preset upper limit value, and determines whether local thinning occurs, local thinning The thickness variation of the pipe 10 at the time of manufacture and the discontinuity of the surface are reflected in the point that the position and the degree of thinning of the pipe 10 can be efficiently predicted and analyzed and the deviation value of the thickness of the pipe 10 measured at another point of time is used Therefore, it is possible to judge whether or not the local pipe 10 of the pipe 10 is thinned and the position of localized thinning.

5A and 5B illustrate a table for explaining a method of obtaining a group-specific test statistic by the thinning discrimination system according to an embodiment of the present invention.

Referring to FIG. 5A, Table 8 is a table corresponding to the coordinate information of the deviation values calculated by the deviation value calculating unit 130, and Table 9 is a table corresponding to Table 4 of FIG. 4A. It is classified into groups.

The group classification unit 150 may classify a plurality of grid points into a plurality of groups based on the coordinate information as shown in Table 9. [ Referring to Table 9, the group classifier 150 classifies the grid points arranged by 12 by 12 into 4 groups by grouping the adjacent grid points. For example, the group classifying unit 150 can divide a plurality of grid points having the deviation values of Table 8 into nine groups of 16, as shown in Table 9. [

The discrete-time variable detecting unit 160 detects the number of lattice points having a deviation value equal to or greater than a predetermined upper limit value described above with reference to FIG. 2 in the same group and the number of lattice points having a deviation value less than the predetermined upper- . At this time, the preset upper limit value is set to a value corresponding to a preset upper limit value set in the lattice point extracting unit 140 described with reference to FIG.

For example, the discrete-parameter detecting unit 160 detects four discrete variables and 12 unshakable broths for the first group, one dehydrated water and fifteen unshakable water for the second group, and 0 dehydrated water for the third group And 16 untreated broths. For the 4th group, 0 shrubs and 16 unshaken broodstocks. For the 5th group, 1 shrub and 15 unshrimed broths. For the 6th group, 2 shrubs and 14 unshaken broodstocks , Group 2 and group 14 of unsuspected broth, group 4 and group 12 of undiluted broth, group 1 and group 11, respectively. The deviation value can be discretized.

According to one embodiment, when the discrete variable detecting unit 160 transmits the discretization information and the disassembled disassembly information for each group to the discarding discarding unit 170, Calculate the test statistic between each group. For example, if a null hypothesis is established in which each of the groups is subdivided equally between the sweetened water and the untreated water based on the sweetened water and the untreated water of all groups, the thinning determination unit 170 determines that the sweetened water and un- The test statistic of the groups can be calculated based on the significance level between the expected group and the actual group.

In addition, the thinning discrimination unit 170 compares the calculated test statistic with the reference statistic at a predetermined significance level. The significance level refers to the error level of judgment on the null hypothesis when the null hypothesis is actually true in the statistical hypothesis test, and may be set to a value between 0.01 and 0.05. For example, when the significance level is set to 0.05, when the test statistic is less than 0.05 in the null hypothesis as described above, it means that the lattice points having a deviation value equal to or greater than the preset upper limit value are arranged closely to each other, The thinning determination unit 170 can determine that localized thinning has occurred in one region of the pipe 10. [

 According to one embodiment, the thinning determination unit 170 may calculate a test statistic using a chi-square test based on the information on the gravy and non-gravy in each of the plurality of groups. For example, when a null hypothesis is set that the sweetened water and unsalted water are evenly distributed in each group based on the sweetened water and unsalted water of all groups, , A value of 0.14873 can be obtained by calculating the test statistic of the nine groups as shown in Fig. This is because the thinning discrimination unit 170 can determine that localized thinning does not occur in one region of the pipe 10 at a value greater than the significance level of 0.05.

Referring to FIG. 5A, Table 10 is a deviation table corresponding to the coordinate information corresponding to the deviation values calculated by the deviation value calculating unit 130, and Table 11 is a table corresponding to Table 9 evenly. It is classified into groups.

The discrete variable detecting unit 160 may classify a plurality of grid points into a plurality of groups based on the coordinate information as shown in Table 11. [ Referring to Table 11, as shown in Table 9, the discrete parameter detector 160 divides the grid points arranged by 12 by 12 into 4 groups of 4 and divides them into one group. do.

For example, the discrete variable detecting unit 160 can divide a plurality of grid points having a deviation value corresponding to Table 10 into nine groups of 16 by 16 as shown in Table 11, and detect the decimated and untreated water of each group . In Table 11, the discrete variable detection unit 160 calculates the discrete variable detection unit 160 for the first group to the fourth group with 0 decimated water and 16 unimpressed water, 7th decimated water and 9 unutilized water for the fifth group, For the seventh group, zero and six unscented grains are to be detected, and eight grains and eight unscented grains are to be detected for the 8th group, and 0 grains and 16 unstained grains are to be detected for the 9th group.

According to one embodiment, the thinning determination unit 170 may calculate a test statistic using a chi-square test based on the information on the gravy and non-gravy in each of the plurality of groups. For example, when a null hypothesis is established that the sweetened water and unsalted water are evenly distributed in each group on the basis of the sweetened water and the untreated water of all groups, Calculating the test statistic for the nine groups as shown in FIG. 5, a value of 7.52195E ^-10 can be obtained. That is, the null hypothesis is rejected at a value significantly smaller than the significance level of 0.05, so that the thinning discrimination unit 170 can determine that local thinning has occurred in one region of the pipe 10.

In addition, the thinning determination unit 170 can detect the position of the pipe where the localized thinning occurs, based on the coordinate information corresponding to the extracted grid points. When the position of the pipe 10 where the localized thinning occurs is detected, the thinning determining unit 170 may provide information on the position of the pipe to an external display device or the like. It is possible to easily recognize to which portion in the piping 10 the local thinning occurs frequently based on the information.

In this case, the thinning discrimination system 100 classifies a plurality of grid points into groups, statistically analyzes the detected thickness of each group, It is possible to quickly and accurately determine whether localized thinning has occurred in one region of the pipe 10. In addition, since the thinning discrimination system 100 can accurately determine whether or not the local thinning of the pipe occurs, and can provide information on the accurate position, the thinning discrimination system 100 can be applied to the piping 10 of a large number of industrial equipments, Unnecessary repetitive measurements, improper equipment maintenance and replacement can be minimized to improve the safety and economy of industrial facilities.

6A and 6B are views for explaining a method for determining whether local thinning occurs in one region of a piping according to another embodiment of the present invention.

Referring to FIG. 6A, Table 12 is a table listing the deviation values for the grid points classified into groups in Table 4 of FIG. 4A, and Table 13 shows the sum, average, and variance And Table 14 is a dispersion analysis table in which a plurality of groups are subjected to a variance analysis on the basis of Table 13.

When the information on the group-specific deviation values as shown in Table 12 is input, the thinning-discrimination unit 170 obtains statistical characteristics such as sum, average, and variance of the deviation values for each group. The thinning determination unit 170 determines a significant difference between the plurality of groups as shown in Table 14 based on the statistical characteristics. The thinning discrimination unit 170 obtains a test statistic according to a significant difference between the groups and confirms whether the test statistic has a value equal to or less than a reference statistic at a predetermined significance level. If the test statistic has a value less than the reference statistic at the predetermined significance level, the thinning judging unit 170 judges that local thinning has occurred in one region of the pipe 10.

Upon receiving the input as shown in Table 12, the thinning discrimination unit 170 calculates statistical characteristics such as sum, average, and variance of the deviation values of the plurality of groups as shown in Table 13. [ The thinning discrimination unit 170 can obtain a significant difference and a test statistic by calculating the sum of squares, the degree of freedom, and the root mean square based on the statistical characteristics thus calculated. This is a variance analysis method based on the one-way method. Referring to Table 14, the significant difference (F) between Table 12 calculated by the thinning discrimination unit 170 is 1.7084 and the test statistic is 0.1018. If the reference statistic at the predetermined significance level is 0.05, the test statistic between the groups in Table 12 is greater than 0.05, so that the thinning discrimination unit 170 determines that the local thinning has occurred in one region of the pipe having the deviation value in Table 12 It is determined that it has not occurred.

Referring to FIG. 6B, Table 15 is a table listing the deviation values for the lattice points in each group in Table 6 of FIG. 4B, and Table 16 shows the sum, mean, and variance of the deviation values in each group in Table 15 And Table 17 is an analysis of variance in which the variance analysis among a plurality of groups is performed based on Table 15. [ On the other hand, Table 12 and Table 15 refer to the measured values measured for pipes in different regions.

When the information on the group-specific deviation values as shown in Table 15 is input, the thinning-discrimination unit 170 obtains statistical characteristics such as sum, average, and variance of the deviation values for each group. The thinning determination unit 170 determines a significant difference between the plurality of groups as shown in Table 17 based on the statistical characteristics. The thinning discrimination unit 170 obtains a test statistic according to a significant difference between the groups and confirms whether the test statistic has a value equal to or less than a reference statistic at a predetermined significance level. If the test statistic has a value less than the reference statistic at the predetermined significance level, the thinning judging unit 170 judges that local thinning has occurred in one region of the pipe 10.

When the values shown in Table 15 are input, the thinning discrimination unit 170 calculates statistical characteristics such as sum, average, and variance of the deviation values of each group as shown in Table 16. [ The thinning discrimination unit 170 can obtain a significant difference and a test statistic by calculating the sum of squares, the degree of freedom, and the root mean square based on the statistical characteristics thus calculated. Referring to Table 17, the difference (F) between the groups is 17.61 and the test statistic is 9E- ¹⁸ . If the reference statistic at a predetermined significance level is 0.05, the thinning discrimination unit 170 can determine that local thinning has occurred in one region of the pipe 10 having the same value as in Table 15. [

FIG. 7 is a flowchart illustrating a method for determining whether a thinning of a region of a pipe is to be performed by the thinning discrimination system according to an embodiment of the present invention.

The flowchart shown in FIG. 7 is composed of steps that are processed in a time-series manner in the thinning determination system 100 shown in FIG. Therefore, it is understood that the contents described above with respect to the configurations shown in FIG. 2 apply to the flow chart shown in FIG. 7, even if omitted from the following description.

Referring to FIG. 7, the thinning discrimination system 100 measures a first measured value measured at a first time and a second measured value measured at a second time described with reference to FIG. 1 for one region of a pipe 10, The second measured value is obtained and stored. Specifically, the thinning discrimination system 100 measures the thickness of the pipe 10 at a point where each lattice point is indicated at a first time, and sets the thickness of the measured pipe 10 to a first measured value It is stored in advance. Thereafter, the thickness of the pipe 10, on which the same plurality of grid points are displayed, is re-measured, and information on the thickness of the pipe 10 corresponding to each of the plurality of grid points is added as a second measurement value . When the acquisition and storage of the second measurement value is completed, the thinning determination system 100 compares the first measurement value and the second measurement value, and determines whether localized thinning has occurred in the pipe 10 S101).

Next, the thinning discrimination system 100 calculates a deviation value which is a difference between the first measured value and the second measured value. For example, the thinning discrimination system 100 obtains the thickness of the pipe 10 with respect to a specific lattice point from each of the first measured value and the second measured value, obtains a difference in thickness of the obtained pipe 10, Also, deviation values of how the thickness of the pipe 10 has changed at the same lattice points as described above are calculated from the first measured value and the second measured value with respect to the grid points (S103).

Next, the thinning discrimination system 100 extracts specific lattice points based on the calculated deviation values. The thinning discrimination system 100 selects lattice points that are equal to or greater than a preset upper limit value described with reference to FIG. As described with reference to FIG. 2, the preset upper limit value may be set differently depending on the calculated deviation values. The thinning discrimination system 100 acquires coordinate information corresponding to the extracted grid points when grid points having a predetermined upper limit value or more are extracted. As described with reference to FIG. 1, the coordinate information is determined according to the arrangement and arrangement order of a plurality of grid points, and information about the position on the pipe 10 on which the plurality of grid points are displayed may also be included. For example, the plurality of grid points may be arranged in the circumferential direction of the pipe and the axial direction of the pipe, and the coordinate information may be set according to a sequence arranged in a circumferential direction and an axial direction (S105).

Next, the thinning discrimination system 100 calculates a variance value of the extracted grid points based on the obtained coordinate information (S107).

Next, the thinning discrimination system 100 compares the calculated dispersion value with preset reference values described with reference to FIG. The predetermined reference value varies according to the number of the plurality of lattice points and the number of the extracted lattice points as described above, and may be set in advance according to the probability distribution of the dispersion value. That is, as described with reference to FIG. 2, the predetermined reference value can predict a dispersion value that can be estimated that the extracted grid points are concentrated based on the probability distribution described with reference to FIG. 2 (S109) .

The thinning determination system 100 determines that localized thinning occurs in one region of the pipe 10 when the calculated dispersion value is less than the preset reference value. In this case, the thinning discrimination system 100 can provide an external display device or the like that the local thinning has occurred in one area of the pipe 10. Further, the thinning discrimination system 100 can acquire the position on the pipe 10 on which the grid points are displayed based on the coordinate information of the extracted grid points, and the information on the position on the obtained pipe 10 And may be provided to the external display device (S111).

Alternatively, the thinning determination system 100 determines that localized thinning does not occur in one region of the pipe 10 when the calculated dispersion value is equal to or greater than the preset reference value.

That is, if the variance value is larger than a preset reference value, the thinning discrimination system 100 can estimate that the extracted grid points are uniformly positioned. If the variance value is smaller than a preset reference value, the extracted grid points are concentrated .

Accordingly, when only the information on the thickness of the pipe 10 is input to the thinning discrimination system 100 without the user needing to compare and analyze the results of the measurement of the thickness of the numerous pipes 10, The thinning discrimination system 100 can easily obtain the thickness of the pipe 10 at the time of fabrication because the thinning discrimination system 100 uses a deviation value between a measured value and the measured value again. It is possible to determine whether or not the pipe 10 has been thinned based on accurate information obtained by eliminating errors due to variations, surface discontinuities, and the like.

8 is a flowchart illustrating a method for determining whether a thinning of a region of a pipe is to be performed by a thinning discrimination system according to another embodiment of the present invention.

The flowchart shown in FIG. 8 is composed of the steps of time series processing in the thinning determination system 100 shown in FIG. Therefore, even though omitted from the following description, it can be seen that the above description regarding the configurations shown in FIG. 2 also applies to the flow chart shown in FIG.

Referring to FIG. 8, the thinning discrimination system 100 acquires a first measured value measured at a first time and a second measured value measured at a second time (S201).

Next, based on the first measured value and the second measured value, the thinning discrimination system 100 calculates a deviation value as to how much the thickness changes at each lattice point at the second time (S203).

Next, the thinning discrimination system 100 classifies the plurality of grid points into a plurality of groups. The thinning discrimination system 100 classifies the thinning discrimination system into a plurality of groups based on the coordinate information of the plurality of lattice points. For example, when the plurality of grid points are arranged in the form of 100 by 100 and displayed in one area of the pipe 10, and the plurality of grid points are classified into 10 groups, the thinning discrimination system 100 calculates 10 by 10 units in the axial or circumferential direction of the piping, and then grouped into 10 groups. For example, the thinning discrimination system 100 may equally divide one region of the pipe 10 having a plurality of grid points into a plurality of regions and set the grid points included in each of the equal regions as a group (S205) .

Next, the thinning discrimination system 100 detects the reduced grains and unstained grains in each group. The thinning discrimination system 100 detects the number of lattice points that are equal to or larger than a predetermined upper limit value described with reference to FIG. 2 for each group as a decimated number, and detects the number of lattice points that are less than the predetermined upper limit value as untreated water (S207).

Next, the thinning discrimination system 100 calculates information on the significant difference and the test statistic between each group on the basis of the weighted and unestablished water of each group. For example, as described with reference to FIGS. 5A and 5B, the thinning discrimination system 100 may calculate a significant difference for each group through a chi-square test, and calculate a test statistic based on the calculated significant difference ( S209).

Next, the thinning discrimination system 100 can compare the calculated test statistic with the reference statistic at a predetermined significance level to determine whether local thinning has occurred on a surface of the pipe. The predetermined test statistic described in FIG. 5A is a probability that the null hypothesis can be rejected, and may have a value between 0.01 and 0.05 (S211).

Next, if the calculated test statistic has a value less than the reference statistic at a predetermined significance level, the thinning judgment system 100 judges that local thinning has occurred in one region of the pipeline 10, Coordinate information on lattice points having a deviation value may be obtained to estimate and determine the position on the pipe 10 where the localized thinning occurs (S213).

On the other hand, when the test statistic is equal to or greater than the reference statistic at the predetermined significance level, it is estimated that the grid points having a predetermined upper limit value or more are distributed relatively uniformly in one region of the pipeline 10 as described with reference to FIGS. 5A and 5B And the thinning discrimination system 100 judges that local thinning does not occur in one region of the pipe 10.

9 is a flowchart illustrating a method for determining whether a thinning of a region of a pipe is to be performed by the thinning discrimination system according to another embodiment of the present invention.

The flowchart shown in FIG. 9 consists of the steps of time series processing in the thinning determination system 100 shown in FIG. Therefore, even if omitted from the following description, it can be seen that the above description regarding the configurations shown in FIG. 2 also applies to the flow chart shown in FIG.

Referring to FIG. 9, the thinning discrimination system 100 acquires a first measured value measured at a first time and a second measured value measured at a second time (S301).

Next, based on the first measured value and the second measured value, the thinning discrimination system 100 calculates a deviation value as to how much the thickness changes at each lattice point at the second time (S303).

Next, the thinning discrimination system 100 classifies the plurality of grid points into a plurality of groups. The thinning discrimination system 100 classifies the thinning discrimination system 100 into a plurality of groups based on the coordinate information of the plurality of grid points as described with reference to FIG. 8 (S305).

Next, the thinning discrimination system 100 calculates the total sum, the average, the variance, and the like, which are statistical characteristics of the deviation values for each group. The thinning discrimination system 100 performs an analysis of variance between a plurality of groups based on the statistical characteristics of the respective groups. In this case, the thinning discrimination system 100 can analyze the statistical characteristics of each group using the deviation values of the respective groups as they are, and calculate the significant difference between the plurality of groups based on the analyzed statistical characteristics (S307 ).

Next, the thinning discrimination system 100 can calculate a significant difference and a test statistic between groups based on the analysis of variance between the plurality of groups. For example, the thinning discrimination system 100 can perform the variance analysis according to the one-way method as described with reference to FIGS. 6A and 6B (S309).

Next, the thinning discrimination system 100 compares the reference statistic with the test statistic at a preset significance level as described with reference to FIG. 8 (S311).

If the calculated test statistic is less than the reference statistic at the predetermined significance level, the thinning judgment system 100 judges that local thinning has occurred in one region of the pipeline 10. In this case, the thinning discrimination system 100 can extract lattice points having a deviation value equal to or greater than a preset upper limit value described with reference to FIG. The thinning discrimination system 100 obtains coordinate information corresponding to the extracted grid points. The thinning discrimination system 100 can estimate the position information of the extracted grid points on the pipe 10 based on the coordinate information and provide the information on the display as an external device (S313).

The embodiments of the present invention described above can be embodied in the form of a computer program that can be executed on various components on a computer, and the computer program can be recorded on a computer-readable medium. At this time, the medium may be a magnetic medium such as a hard disk, a floppy disk and a magnetic tape, an optical recording medium such as CD-ROM and DVD, a magneto-optical medium such as a floptical disk, , A RAM, a flash memory, and the like, which are specifically configured to store and execute program instructions.

Meanwhile, the computer program may be designed and configured specifically for the present invention or may be known and used by those skilled in the computer software field. Examples of computer programs may include machine language code such as those produced by a compiler, as well as high-level language code that may be executed by a computer using an interpreter or the like.

The specific acts described in the present invention are, by way of example, not intended to limit the scope of the invention in any way. For brevity of description, descriptions of conventional electronic configurations, control systems, software, and other functional aspects of such systems may be omitted. Also, the connections or connection members of the lines between the components shown in the figures are illustrative of functional connections and / or physical or circuit connections, which may be replaced or added by a variety of functional connections, Connection, or circuit connections. Also, unless explicitly referred to as " essential ", " important ", etc., it may not be a necessary component for application of the present invention.

10: Piping
100: Thinning discrimination system
110:
120: Data collection unit
130: Deviation value calculation unit
140: lattice point extracting unit
150: Group classification section
160: Discrete variable detector
170: thinning discrimination unit

Claims (23)

1. A thinning discrimination method for discriminating a change in thickness of a pipe by measuring a thickness of the pipe at each of a plurality of lattice points, wherein a plurality of lattice points are defined in one area,
Obtaining a first measurement value, which is a measurement value of the pipe thickness measured at the first time, and a second measurement value, which is a measurement value of the pipe thickness measured at a second time after the first time;
Calculating a deviation value based on the first measurement value and the second measurement value; And
And analyzing statistical characteristics of the deviation value to determine whether localized thinning of the pipe occurs or not. The method according to claim 1,
Extracting the lattice point having a deviation value equal to or greater than a predetermined upper limit value; And
And obtaining coordinates information corresponding to the extracted lattice points. 3. The method of claim 2,
And calculating a variance value between the extracted lattice points based on the obtained coordinate information. The method of claim 3,
Wherein the step of determining the local thinning of the pipe comprises:
Comparing the preset reference value and the calculated variance value with each other; And
And determining that localized thinning has occurred in one region of the pipe when the calculated dispersion value is less than a preset reference value. 5. The method of claim 4,
Wherein the step of determining the local thinning of the pipe comprises:
And estimating a position at which the pipe is thinned based on the coordinate information corresponding to each of the extracted grid points. 3. The method of claim 2,
And classifying the plurality of grid points into a plurality of groups based on the coordinate information,
Wherein the grid points in each group are adjacent to each other. The method according to claim 6,
In the step of classifying into the plurality of groups
And dividing the plurality of groups so that the same number of grid points are included among the plurality of groups. The method according to claim 6,
The step of determining the thinning state of the pipe includes:
Analyzing statistical characteristics such as sum, mean and variance between the deviation values of the grid points in the group;
And calculating a test statistic for a significant difference between the plurality of groups based on the statistical characteristic. 9. The method of claim 8,
The step of determining the thinning state of the pipe includes:
Comparing the test statistic with a reference statistic at a predetermined significance level; And
And determining that localized thinning has occurred in one region of the pipe if the test statistic is less than a reference statistic at a predetermined significance level. The method according to claim 6,
Calculating a number of lattice points having a deviation value equal to or greater than a preset upper limit value for each of the classified groups and a number of lattice points having a deviation value less than the predetermined upper limit value, Way. 11. The method of claim 10,
The step of determining the thinning state of the pipe includes:
And comparing the reduced gravy and the untreated gravy between the groups to calculate a test statistic for a significant difference between the groups. A thinning discrimination system for determining a thinning of a thickness of a pipe through nondestructive inspection at each of a plurality of lattice points, wherein a plurality of lattice points are defined in one region of a pipe,
A measuring unit measuring the thickness of the pipe at each of the plurality of grid points;
A first measurement value, which is a measurement value for the thickness of the pipe measured at each of the plurality of grid points measured by the measurement unit from a first time, and a second measurement value at a second time after the first time, A data collection unit for storing a second measurement value, which is a measurement value of the thickness of the pipe measured at each of the grid points;
A deviation value calculating unit for calculating a deviation value at each of the lattice points based on the first measured value and the second measured value; And
And a thinning discrimination unit for discriminating whether or not thinning of the pipe occurs based on statistical characteristics of the deviation value. 13. The method of claim 12,
And a lattice point extraction unit for extracting the lattice points having a deviation value equal to or greater than a preset upper limit value,
Wherein the coordinate information based on the arrangement type and the arrangement order of the plurality of grid points is set. 14. The method of claim 13,
Wherein the thinning discrimination unit obtains the coordinate information corresponding to the extracted lattice points and calculates a variance value between the extracted lattice points. 15. The method of claim 14,
Wherein the thinning discrimination unit compares the dispersion value with a preset reference value and determines that localized thinning has occurred in the pipe corresponding to the one area if the dispersion value is less than the preset reference value. 16. The method of claim 15,
And the thinning discrimination unit estimates the position of the pipe where the local thinning occurs based on the obtained coordinate information. 14. The method of claim 13,
And a group classifier for classifying the plurality of grid points into a plurality of groups based on the coordinate information. 18. The method of claim 17,
The thinning discrimination unit analyzes statistical characteristics such as sum, average and variance between the deviation values of the grid points in each group,
And a test statistic for a significant difference between a plurality of groups is calculated based on the analyzed statistical characteristics. 19. The method of claim 18,
Wherein the thinning discrimination unit discriminates that localized thinning has occurred in one region of the pipe if the test statistic is less than a reference statistic at a predetermined significance level. 18. The method of claim 17,
And a discrete variable detector for detecting a decimated number which is the number of the lattice points having a deviation value equal to or larger than a predetermined reference value for each of the classified groups and a number of lattice points having a deviation value less than the preset reference value Features a thinning discrimination system. 21. The method of claim 20,
Wherein the thinning discrimination unit calculates a test statistic for a significant difference between the plurality of groups based on the decolorized water and the unestimated water in each of the groups. 22. The method of claim 21,
Wherein the thinning determination unit determines that localized thinning has occurred in one region of the pipe if the calculated test statistic has a value less than a reference statistic at a predetermined significance level. A computer-readable recording medium on which a program for executing the method of any one of claims 1 to 11 is recorded.

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