Jinyi Lee - Academia.edu (original) (raw)

Papers by Jinyi Lee

Applied Sciences

An aircraft is a multilayer structure that is assembled by rivets. Under extreme working conditio... more An aircraft is a multilayer structure that is assembled by rivets. Under extreme working conditions, corrosion appears and quickly propagates at the rivet sites of the layers; thus, it threads the integrity and safety of the aircraft. Corrosion usually occurs at the hidden layer around the rivet, making it difficult to detect. This paper proposes a machine learning approach incorporating an electromagnetic testing system to detect the hidden corrosion at the riveting site effectively. Several machine learning methods will be investigated for the detection of different sizes and locations of corrosion. The training strategy of the machine-learning models on the small numbers of data will also be investigated. The result shows that the proposed approach could effectively detect 89.48% of the hidden corrosion having from 2.8 to 195.4 mm3 with only 20% of training data and could be increased to 99.0% with 60–80% of the training data.

Russian Journal of Nondestructive Testing

Applied Sciences

Carbon steels are commonly used in railroad, shipment, building, and bridge construction. They pr... more Carbon steels are commonly used in railroad, shipment, building, and bridge construction. They provide excellent ductility and toughness when exposed to external stresses. They are able to resist stresses and strains effectively, and guarantee safe operation of the devices through nondestructive testing (NDT). The magnetic metal memory (MMM) can be used as an NDT method to measure the residual stress. The ability of carbon steel to produce a magnetic memory effect under stress is explored here, and enables the magnetic flux density to be analyzed. The relationship between stress and magnetic flux density has not been fully presented until now. The purpose of this paper is to assess the relationship between stress distribution and the magnetic flux density measured by the experiment. For this, an experimental method for examining a carbon steel plate (SA 106), based on the four-point loading test, was used. The effect of stresses resulting from the applied loads on the response of th...

2019 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 2019

In this study, bobbin-type magnetic cameras for nondestructive inspection of small diameter tubes... more In this study, bobbin-type magnetic cameras for nondestructive inspection of small diameter tubes are reported. Two types of magnetic cameras were used to image eddy currents using exciting coils and annularly arrayed magnetic sensors, in order to detect and evaluate defects. The performance of both magnetic cameras was compared and verified using artificial defects introduced into the tubular test specimen of austenitic stainless steel 304 with 13.3 mm inner diameter.

Applied Sciences, 2021

In this paper, a nondestructive inspection system is proposed to detect and quantitatively evalua... more In this paper, a nondestructive inspection system is proposed to detect and quantitatively evaluate the size of the near- and far-side damages on the tube, membrane, and weld of the water-cooled wall in the fluidized bed boiler. The shape and size of the surface damages can be evaluated from the magnetic flux density distribution measured by the magnetic sensor array on one side from the center of the magnetizer. The magnetic sensors were arrayed on a curved shape probe according to the tube’s cross-sectional shape, membrane, and weld. On the other hand, the couplant was doped to the water-cooled wall, and a thin film was formed thereon by polyethylene terephthalate. Then, the measured signal of the flexible ultrasonic probe was used to detect and evaluate the depth of the damages. The combination of the magnetic and ultrasonic methods helps to detect and evaluate both near and far-side damages. Near-side damages with a minimum depth of 0.3 mm were detected, and the depth from the s...

In order to detect defects on steel surface using a non-contact method in adverse surrounding wit... more In order to detect defects on steel surface using a non-contact method in adverse surrounding with the presence of high temperature, dust and vibration using magnetic flux leakage testing, it is necessary to increase the lift-off distance from the specimen surface to the sensor from the previous 0.5mm to within 5mm. For this purpose, we need a new technique of increasing and concentrating leakage magnetic flux developed by defects, and the proposed magnetic camera could give the answer. [6]~[8] The magnetic camera is the equipment that quantitatively visualizes the distribution of magnetic flux density in the surrounding by magnetizing the specimen using a magnetic source. By employing 3-D magnetic fluid (magnetic lens) on the opposite side of the magnetic sensor, it concentrates and increases weak magnetic flux density. In this study, a quantitative algorithm using the scan-type magnetic camera, the type used to overcome spatial limitation due to the sensor size among different cam...

Materials evaluation, 2018

Volume 5: High-Pressure Technology; Rudy Scavuzzo Student Paper Symposium and 27th Annual Student Paper Competition; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD), 2019

Liquid penetrant testing (PT), magnetic particle testing (MT) and ultrasonic testing (UT) have be... more Liquid penetrant testing (PT), magnetic particle testing (MT) and ultrasonic testing (UT) have been used as nondestructive testing methods for the welded tubular joints of reactor cooling systems. The PT and the MT that are applied to the surface test of the specimen have been experiencing problems such as specimen contamination, hazardous chemical exposure risk for the inspector, and the inspector’s extended time in the nuclear power plant due to the long testing time (increased risk of radiation exposure). This study is about the applicability of an alternative nondestructive examination (ANDE) method to solve the aforementioned problems. According to the requirements of ANDE, the NDE technology should be applied with the same or better sensitivity and shorter inspection time than the conventional inspection methods of PT and MT. In order to satisfy these requirements, a flexible-type multi-sensor array was developed in order to scan a certain welding area and complete the inspect...

Semi-shield tunneling is one of the propulsion construction methods used to lay pipes underground... more Semi-shield tunneling is one of the propulsion construction methods used to lay pipes underground between two pits named ‘entrance’ and ‘destination’, respectively. Usually a simple composition, such as ‘a fiducial target at the entrance+a total station (TS)+a target on the machine’, is used to confirm the planned course. However, unavoidable curved sections are present in small-sized pipe lines, which are laid after implementation of a road system, for public works such as waterworks, sewer, electrical power, and gas and communication networks. Therefore, if the planned course has a curved section, it is difficult to survey the course with the abovementioned simple composition. This difficulty could be solved by using the multiple total stations (MTS), which attaches the cross type linear LED target to oneself. The MTS are disposed to where each TS can detect the LED target at the other TS or the base point or the machine. And the accurate relative positions between each MTS and ta...

Measurement, 2021

Magnetic flux leakage testing (MFLT) is an important nondestructive testing method for the detect... more Magnetic flux leakage testing (MFLT) is an important nondestructive testing method for the detection and evaluation of defects in magnetic materials. Magnetic field distribution in an MFLT system is usually simulated by the finite element method (FEM), which required large memory, high computation, and complication of the meshing process. In this paper, an alternative simulation method will be proposed using a deep neural network (DNN). The DNN method provides an easy way of simulation by feeding only the distribution of supplied current and the physical properties such as magnetic permeability without the need for the meshing process. Defects with arbitrary sizes were simulated under different configurations of the MFLT systems. The DNN was trained on the simulation results of the FEM and provided an accurate prediction of the magnetic field distribution of the unseen data. This study paves the way for designing optimized MFLT systems in a bigdata-driven method.

Measurement, 2018

This paper proposes an ultrasonic testing system for inspection of pitting corrosion cracks in ri... more This paper proposes an ultrasonic testing system for inspection of pitting corrosion cracks in rivets of multilayer structures. The inspection operates in B-scan mode with an ultrasonic probe passing over the rivet head. The ultrasonic signal is analyzed in the frequency domain using the short-time Fourier transform. To analyze and evaluate the effectiveness of the system, B-scan data obtained by scanning a rivet head within ±1 mm from the rivet head center will be used and an algorithm to evaluate the existence of cracks in the rivet using B-scan data will be proposed. To evaluate the performance of the system, its probability of detection (POD) is analyzed. With the data obtained at a scanning speed of 6 mm/s, the system could detect artificial pitting corrosion cracks with areas of 47.28% of the rivet body cross-section area with 90/95% POD.

International Journal of Applied Electromagnetics and Mechanics, 2018

The proceedings of the JSME annual meeting, 2006

Nondestructive Testing and Evaluation, 2017

Do c and Jinyi Lee a,b a research center for it-based real time Ndt, chosun university, gwangju, ... more Do c and Jinyi Lee a,b a research center for it-based real time Ndt, chosun university, gwangju, south of Korea; b department of control, instrumentation and robot engineering, chosun university, gwangju, south of Korea; c KePco Plant service and engineering co., ltd, Busan, south of Korea ABSTRACT This paper presents a nondestructive testing system for inspecting the moisture separator reheater (MSR) tubing system in a nuclear power plant. The technique is based on partial saturation eddy current testing in which a Hall sensor array is used to measure the radial component of the electromagnetic field distributed in the tubes. A finned MRS tube of ferritic stainless steel (SS439) with artificial, flatbottom hole-type defects was used in the experiments. The results show that the proposed system has potential applications in the MSR system or ferromagnetic material tubes in general, which could detect the artificial defects of about 20% of the wall thickness (0.24 mm). Furthermore, the defect volume could be quantitatively evaluated.

International Journal of Applied Electromagnetics and Mechanics, 2017

Journal of Mechanical Science and Technology, 2016

This research proposes a nondestructive inspection system for inspecting and localizing corrosion... more This research proposes a nondestructive inspection system for inspecting and localizing corrosion and fatigue cracks around rivets in air-intake structures. The system uses 64 InSb Hall sensor elements arrayed at a high spatial interval of 0.52 mm. Rivet detection and damage detection algorithms will be proposed. Analysis of the receiver operating characteristic curve and Probability of detection (POD) will be carried out to evaluate the performance of the system and detection algorithms. Artificial corrosion around a rivet with a minimum volume of 11.02 mm 3 could be detected with 90/95% POD and artificial fatigue crack with minimum length of 2.95 mm from rivet body.

International Journal of Precision Engineering and Manufacturing, 2016

This research proposes an ultrasonic testing method for inspecting pitting corrosion cracks in a ... more This research proposes an ultrasonic testing method for inspecting pitting corrosion cracks in a rivet of multilayer structures. The system is a combination of a magnetic sensor array and an ultrasonic sensor. The magnetic sensor array is used to automatically measure the presence of a rivet and its center position. Then, the ultrasonic sensor is guided to the rivet center in order to inspect pitting corrosion cracks in the rivet. The magnetic sensor uses a 64-Hall sensor elements array with a 0.52-mm interval that can measure the rivet center position at a standard deviation of 0.27 mm and 0.42 mm in the scan and sensor directions, respectively. The ultrasonic signal is analyzed in the frequency domain using the short-time Fourier transform that helps better observe the presence of cracks compared with the conventional signal analysis in A-scan present.

International Journal of Applied Electromagnetics and Mechanics, 2016

Applied Sciences

An aircraft is a multilayer structure that is assembled by rivets. Under extreme working conditio... more An aircraft is a multilayer structure that is assembled by rivets. Under extreme working conditions, corrosion appears and quickly propagates at the rivet sites of the layers; thus, it threads the integrity and safety of the aircraft. Corrosion usually occurs at the hidden layer around the rivet, making it difficult to detect. This paper proposes a machine learning approach incorporating an electromagnetic testing system to detect the hidden corrosion at the riveting site effectively. Several machine learning methods will be investigated for the detection of different sizes and locations of corrosion. The training strategy of the machine-learning models on the small numbers of data will also be investigated. The result shows that the proposed approach could effectively detect 89.48% of the hidden corrosion having from 2.8 to 195.4 mm3 with only 20% of training data and could be increased to 99.0% with 60–80% of the training data.

Russian Journal of Nondestructive Testing

Applied Sciences

Carbon steels are commonly used in railroad, shipment, building, and bridge construction. They pr... more Carbon steels are commonly used in railroad, shipment, building, and bridge construction. They provide excellent ductility and toughness when exposed to external stresses. They are able to resist stresses and strains effectively, and guarantee safe operation of the devices through nondestructive testing (NDT). The magnetic metal memory (MMM) can be used as an NDT method to measure the residual stress. The ability of carbon steel to produce a magnetic memory effect under stress is explored here, and enables the magnetic flux density to be analyzed. The relationship between stress and magnetic flux density has not been fully presented until now. The purpose of this paper is to assess the relationship between stress distribution and the magnetic flux density measured by the experiment. For this, an experimental method for examining a carbon steel plate (SA 106), based on the four-point loading test, was used. The effect of stresses resulting from the applied loads on the response of th...

2019 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 2019

In this study, bobbin-type magnetic cameras for nondestructive inspection of small diameter tubes... more In this study, bobbin-type magnetic cameras for nondestructive inspection of small diameter tubes are reported. Two types of magnetic cameras were used to image eddy currents using exciting coils and annularly arrayed magnetic sensors, in order to detect and evaluate defects. The performance of both magnetic cameras was compared and verified using artificial defects introduced into the tubular test specimen of austenitic stainless steel 304 with 13.3 mm inner diameter.

Applied Sciences, 2021

In this paper, a nondestructive inspection system is proposed to detect and quantitatively evalua... more In this paper, a nondestructive inspection system is proposed to detect and quantitatively evaluate the size of the near- and far-side damages on the tube, membrane, and weld of the water-cooled wall in the fluidized bed boiler. The shape and size of the surface damages can be evaluated from the magnetic flux density distribution measured by the magnetic sensor array on one side from the center of the magnetizer. The magnetic sensors were arrayed on a curved shape probe according to the tube’s cross-sectional shape, membrane, and weld. On the other hand, the couplant was doped to the water-cooled wall, and a thin film was formed thereon by polyethylene terephthalate. Then, the measured signal of the flexible ultrasonic probe was used to detect and evaluate the depth of the damages. The combination of the magnetic and ultrasonic methods helps to detect and evaluate both near and far-side damages. Near-side damages with a minimum depth of 0.3 mm were detected, and the depth from the s...

In order to detect defects on steel surface using a non-contact method in adverse surrounding wit... more In order to detect defects on steel surface using a non-contact method in adverse surrounding with the presence of high temperature, dust and vibration using magnetic flux leakage testing, it is necessary to increase the lift-off distance from the specimen surface to the sensor from the previous 0.5mm to within 5mm. For this purpose, we need a new technique of increasing and concentrating leakage magnetic flux developed by defects, and the proposed magnetic camera could give the answer. [6]~[8] The magnetic camera is the equipment that quantitatively visualizes the distribution of magnetic flux density in the surrounding by magnetizing the specimen using a magnetic source. By employing 3-D magnetic fluid (magnetic lens) on the opposite side of the magnetic sensor, it concentrates and increases weak magnetic flux density. In this study, a quantitative algorithm using the scan-type magnetic camera, the type used to overcome spatial limitation due to the sensor size among different cam...

Materials evaluation, 2018

Volume 5: High-Pressure Technology; Rudy Scavuzzo Student Paper Symposium and 27th Annual Student Paper Competition; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD), 2019

Liquid penetrant testing (PT), magnetic particle testing (MT) and ultrasonic testing (UT) have be... more Liquid penetrant testing (PT), magnetic particle testing (MT) and ultrasonic testing (UT) have been used as nondestructive testing methods for the welded tubular joints of reactor cooling systems. The PT and the MT that are applied to the surface test of the specimen have been experiencing problems such as specimen contamination, hazardous chemical exposure risk for the inspector, and the inspector’s extended time in the nuclear power plant due to the long testing time (increased risk of radiation exposure). This study is about the applicability of an alternative nondestructive examination (ANDE) method to solve the aforementioned problems. According to the requirements of ANDE, the NDE technology should be applied with the same or better sensitivity and shorter inspection time than the conventional inspection methods of PT and MT. In order to satisfy these requirements, a flexible-type multi-sensor array was developed in order to scan a certain welding area and complete the inspect...

Semi-shield tunneling is one of the propulsion construction methods used to lay pipes underground... more Semi-shield tunneling is one of the propulsion construction methods used to lay pipes underground between two pits named ‘entrance’ and ‘destination’, respectively. Usually a simple composition, such as ‘a fiducial target at the entrance+a total station (TS)+a target on the machine’, is used to confirm the planned course. However, unavoidable curved sections are present in small-sized pipe lines, which are laid after implementation of a road system, for public works such as waterworks, sewer, electrical power, and gas and communication networks. Therefore, if the planned course has a curved section, it is difficult to survey the course with the abovementioned simple composition. This difficulty could be solved by using the multiple total stations (MTS), which attaches the cross type linear LED target to oneself. The MTS are disposed to where each TS can detect the LED target at the other TS or the base point or the machine. And the accurate relative positions between each MTS and ta...

Measurement, 2021

Magnetic flux leakage testing (MFLT) is an important nondestructive testing method for the detect... more Magnetic flux leakage testing (MFLT) is an important nondestructive testing method for the detection and evaluation of defects in magnetic materials. Magnetic field distribution in an MFLT system is usually simulated by the finite element method (FEM), which required large memory, high computation, and complication of the meshing process. In this paper, an alternative simulation method will be proposed using a deep neural network (DNN). The DNN method provides an easy way of simulation by feeding only the distribution of supplied current and the physical properties such as magnetic permeability without the need for the meshing process. Defects with arbitrary sizes were simulated under different configurations of the MFLT systems. The DNN was trained on the simulation results of the FEM and provided an accurate prediction of the magnetic field distribution of the unseen data. This study paves the way for designing optimized MFLT systems in a bigdata-driven method.

Measurement, 2018

This paper proposes an ultrasonic testing system for inspection of pitting corrosion cracks in ri... more This paper proposes an ultrasonic testing system for inspection of pitting corrosion cracks in rivets of multilayer structures. The inspection operates in B-scan mode with an ultrasonic probe passing over the rivet head. The ultrasonic signal is analyzed in the frequency domain using the short-time Fourier transform. To analyze and evaluate the effectiveness of the system, B-scan data obtained by scanning a rivet head within ±1 mm from the rivet head center will be used and an algorithm to evaluate the existence of cracks in the rivet using B-scan data will be proposed. To evaluate the performance of the system, its probability of detection (POD) is analyzed. With the data obtained at a scanning speed of 6 mm/s, the system could detect artificial pitting corrosion cracks with areas of 47.28% of the rivet body cross-section area with 90/95% POD.

International Journal of Applied Electromagnetics and Mechanics, 2018

The proceedings of the JSME annual meeting, 2006

Nondestructive Testing and Evaluation, 2017

Do c and Jinyi Lee a,b a research center for it-based real time Ndt, chosun university, gwangju, ... more Do c and Jinyi Lee a,b a research center for it-based real time Ndt, chosun university, gwangju, south of Korea; b department of control, instrumentation and robot engineering, chosun university, gwangju, south of Korea; c KePco Plant service and engineering co., ltd, Busan, south of Korea ABSTRACT This paper presents a nondestructive testing system for inspecting the moisture separator reheater (MSR) tubing system in a nuclear power plant. The technique is based on partial saturation eddy current testing in which a Hall sensor array is used to measure the radial component of the electromagnetic field distributed in the tubes. A finned MRS tube of ferritic stainless steel (SS439) with artificial, flatbottom hole-type defects was used in the experiments. The results show that the proposed system has potential applications in the MSR system or ferromagnetic material tubes in general, which could detect the artificial defects of about 20% of the wall thickness (0.24 mm). Furthermore, the defect volume could be quantitatively evaluated.

International Journal of Applied Electromagnetics and Mechanics, 2017

Journal of Mechanical Science and Technology, 2016

This research proposes a nondestructive inspection system for inspecting and localizing corrosion... more This research proposes a nondestructive inspection system for inspecting and localizing corrosion and fatigue cracks around rivets in air-intake structures. The system uses 64 InSb Hall sensor elements arrayed at a high spatial interval of 0.52 mm. Rivet detection and damage detection algorithms will be proposed. Analysis of the receiver operating characteristic curve and Probability of detection (POD) will be carried out to evaluate the performance of the system and detection algorithms. Artificial corrosion around a rivet with a minimum volume of 11.02 mm 3 could be detected with 90/95% POD and artificial fatigue crack with minimum length of 2.95 mm from rivet body.

International Journal of Precision Engineering and Manufacturing, 2016

This research proposes an ultrasonic testing method for inspecting pitting corrosion cracks in a ... more This research proposes an ultrasonic testing method for inspecting pitting corrosion cracks in a rivet of multilayer structures. The system is a combination of a magnetic sensor array and an ultrasonic sensor. The magnetic sensor array is used to automatically measure the presence of a rivet and its center position. Then, the ultrasonic sensor is guided to the rivet center in order to inspect pitting corrosion cracks in the rivet. The magnetic sensor uses a 64-Hall sensor elements array with a 0.52-mm interval that can measure the rivet center position at a standard deviation of 0.27 mm and 0.42 mm in the scan and sensor directions, respectively. The ultrasonic signal is analyzed in the frequency domain using the short-time Fourier transform that helps better observe the presence of cracks compared with the conventional signal analysis in A-scan present.

International Journal of Applied Electromagnetics and Mechanics, 2016