A5088832840- Ultrasonics and Acoustic Wave Propagation
- Structural Health Monitoring Techniques
- Non-Destructive Testing Techniques
- Thermography and Photoacoustic Techniques
- Welding Techniques and Residual Stresses
- Hydrogen embrittlement and corrosion behaviors in metals
- Electrical Fault Detection and Protection
- Urban Green Space and Health
- Engineering Applied Research
- High-Velocity Impact and Material Behavior
- Fatigue and fracture mechanics
- Diverse Approaches in Healthcare and Education Studies
- Crop Yield and Soil Fertility
- Nuclear Engineering Thermal-Hydraulics
- Internet of Things and Social Network Interactions
Korea Atomic Energy Research Institute
2015-2022
Sungkyunkwan University
2019
Chungbuk National University
2018
Korea Gas Corporation (South Korea)
2015
Accurate and consistent characterization of defects in steam generator tubes (SGT) nuclear power plants is one the key issues field nondestructive testing since large number signals to be analyzed a time-limited in-service inspection causes serious problem practice. This paper presents an effective approach this difficult task automated classification motorized rotating pancake coil (MRPC) eddy current flaw acquired from tube specimens with deliberated using deep neural networks (DNN)....
The interdigital transducer–based scanning laser Doppler vibrometer has recently been introduced to efficiently generate the symmetric mode for damage detection of shallow defects in thick plates. To measure a carbon steel plate, excitation frequency is optimized based on analysis wavenumber sensitivity and degree separation between modes. Even though method using continuous promising visualizing plate-like structures, transducer be coupled media, such as oil or water, minimize variation...
The detection of unexpected loose parts in the primary coolant system a nuclear power plant remains an extremely important issue. It is essential to develop methodology for localization and mass estimation owing high prediction error conventional methods. An effective approach presented part using machine-learning deep-learning algorithms. First, was developed estimate both impact location at same times real structure which geometric changes exist. Second, database constructed through series...
Interdigital transducer (IDT)-based scanning laser Doppler vibrometers (SLDVs) have recently been developed to detect shallow defects in plates. An IDT-based SLDV was augmented with Lamb wave frequency fusion capability enable the imaging of across entire depth a plate. Dry-coupled IDTs are type field-deployable IDT that do not require attachment couplant structure. However, this technique is applicable analysis wall thinning, because composed lead zirconium titanate (PZT) cannot be attached...
A loose part monitoring system is used to detect unexpected parts in a reactor coolant nuclear power plant. It still necessary develop new methodology for the localization and mass estimation of owing high error conventional methods. In addition, model-based diagnostics recently emphasized importance model describing behavior mechanical or component. The purpose this study propose mass-estimation method based on finite element analysis (FEA) optimization technique. First, an FEA simulate...
The visualization of the wall thinning plate-like structures using scanning laser Doppler vibrometry (SLDV) is a promising method in nondestructive evaluation ultrasonics. In particular, Lamb-wave-based SLDV that uses continuous excitation exhibits excellent performance for estimation plates. Currently, plate thickness quantitatively evaluated based on wavenumber analysis measured signals. However, it difficult to estimate automatically below product frequency and 6 MHz·mm without knowing...
This study was conducted to investigate the effects of walking in healing forests for short breaks on mood state, quality life and stress reduction hospital workers.For study, 56 employees from Chungbuk University Hospital participated forest walks connected using a break three times week 20 minutes each weeks.The Korean Version Profile Mood States (K-POMS) Occupational Stress Scale (KOSS-SF) were used as validated measurement tools evaluate changes state job stress.A 5-point Likert scale...
국내 에너지, 석유화학 산업분야에서 주로 사용되는 배관은 다양한 요인에 의해 발생하는 결함들에 대한 검출과 평가가 상시적으로 이슈화되곤 한다. 에너지와 특성상 비교적 긴 거리에 걸쳐 시공되는 경우가 많고 부위에 여러 형태의 결함이 존재하게 되는데, 본 연구를 통해 배관에 보온재 아래의 부식을 보다 효율적으로 검출하기 위한 방법으로 유도초음파 검사기법을 활용하는 시스템과 신호개선방법을 개발했다. 배관 내 결함의 검출능을 높일 수 있는 수단으로 초음파 탐촉자를 배열화하여 유도초음파를 발생시키고 신호대잡음비를 개선할 목적으로 송신 집속기법이 가능하도록 했다. 논문에서는 배열 검사시스템의 개발과 집속을 통한 신호대잡음비 개선에 관해 기술한다. Pipes, commonly used in energy and petrochemical facilities, have various types of defects induced by diverse factors this is often...
인공지능을 이용하여 보온재로 덮혀 있는 배관에서의 결함 신호를 구분하였다. 펄스와전류를 이용한 보온재 비해체 방식의 와전류탐상은 비접촉으로 높은 감도로 표면 결함을 검출할 수 있지만, 신호 판독에 있어서 검사자의 숙련도가 요구된다. 도입하여 숙련도를 대체하기 위하여 실험결과와 데이터를 인공지능으로 처리한 결과를 비교하였다. 10인치 배관에 각각 배관 두께 대비 깊이 50%의 직경 30 mm, 60 90 mm로 가공하여 50 mm 두께를 가진 외부에서 내부결함을 측정하였다. 펄스와전류 신호만으로는 이하의 결함에서는 여부를 확인하기 어렵지만, 결과에서는 확인할 있었다. 본 연구는 의미 없어 보이는 실험결과일지라도 이용하면 유용한 얻을 있음을 보여준다.