• 한국정밀공학회지
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• 제28권9호
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• pp.1094-1102
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• 2011

Recent trends for the miniaturization and weight reduction of portable electronic parts is the use of subminiature components. Assembly of the miniaturized components requires subminiature screws of which pitch sizes are in a micrometer scale. To produce such a subminiature screw with high precision threads, not only a precision forming technology but also high-precision measurement technique is required. In the present work, a vision inspection system is developed to measure the thread profile of a subminiature screw. Optical simulation based on a ray tracing method is used to design and analyze the optical system of the vision inspection apparatus. Through this simulation, optical performance of the developed vision inspection system is optimized. The image processing algorithm for the precision screw inspection is also discussed.

• Spatial Information Research
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• 제8권1호
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• pp.31-50
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• 2000

국가 GIS 구축사업의 일환으로 지형도를 비롯한 여러 가지 주제들이 수치지도로 구축되어왔다. 이렇게 구축된 수치지도는 사용하고자 하는 목적에 맞게 올바르게 구축되어 그 정확도를 신뢰할 수 있을 경우에만 효율적으로 사용될 수 있다. 본 연구의 목적은 양질의 수치지도를 구축하는데 필요한 합리적인 검수방안을 제시하는데 있다. 이를 위해 국내·외에서 요구되는 수치지도의 품질요소와 검수현황을 살펴보았고, 수치지도에서 발생하는 오류유형을 분석했다. 이러한 오류유형을 바탕으로 데이터생성연혁, 데이트포맷, 위치정확성, 속성정확성, 기하구조의 적합성, 논리적 일관성, 경계인접, 완전성, 도곽선 범위의 9가지 기존을 마련한 뒤 작업계획, 오류유형 정의, 납품내역검수, 육안중첩검수, 현지조사검수, 전산정밀검수, 자동검수, 검수결과판정, 검수결과해석으로 이어지는 9단계의 체계적인 다단계 검수절차를 제안하였다.

• 한국정밀공학회지
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• 제13권2호
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• pp.68-75
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• 1996

More accurate inspection method for facilities of nuclear power plants is required to guarantee the continuous and stable energy supply. The portion of inspection for pipes and pressure vessels is relatively big in the power plants. Conventional inspection methods using ultrasonic wave, x-ray and eddy current for nondestructive testing in nuclear power plants have been performed as the method of contact with objects to be inspected. With this reason these methods have been taken relatively much time, money and manpower. And the area to be inspected is limited by the location of probe or film. These difficulties make the inspection into a time-consuming work. We propose an optical defect detection method using phase shifting realtime holographic interferometry. This method has an advantage that the inspection can be performed at a time for relatively wide area illuminated by the laser beam, a coherent light source and can help an inspector recognize not only defects but also the high stressed areas. In this paper we show that the quantitative measurement using holographic interferometry and image processing for defect in pressure vessels is possible.

• Smart Structures and Systems
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• 제13권6호
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• pp.1041-1063
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• 2014

This work introduces a two-module robotic pipe inspection system with ultrasonic NDE device to evaluate the integrity of pipe structures. The proposed robotic platform has high mobility. The two module mobile robot platform overcomes pipe obstacle structures such as elbow, or T-branch joints by cooperative maneuvers. Also, it can climb up the straight pipeline at a fast speed due to the wheel driven mechanism. For inspection of pipe structure, SH-waves generated by EMAT are applied with additional signal processing methods. A wavelet transform is implemented to extract a meaningful and specific signal from the superposed SH-wave signals. Intensity ratio which is normalized the defect signals intensity by the maximum intensity of directly transmitted signals in the wavelet transforms spectrum is applied to evaluate defects quantitatively. It is experimentally verified that the robotic ultrasonic inspection system with EMAT is capable of non-destructive inspection and evaluation of defects in pipe structure successfully by applying signal processing method based on wavelet transform.

• 한국산학기술학회논문지
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• 제13권5호
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• pp.1996-2001
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• 2012

본 시각 검사시스템은 전자 부품과 같이 잘 형성된 표면 재료에 널리 사용되고 있다. 반사 능력이 나쁜 재료의 경우, 시각 검사시스템이 도입될 때 많은 문제점이 발생한다. 혼합 생산 라인에서 진위의 모델을 알 수 없을 때 저 반사비와 많은 노이즈에도 잘 작동할, 강인한 시각 검사시스템을 개발하였다. 유형을 인식하기 위하여 k-means를 이용한 작업물 인식 기법이 제안되었다. 인식 유형에 기반하여 active contour라는 노이즈에 강인한 분할 기법이 영상에서 특징을 분할하는데 응용되었다. 오차 변화를 조정하는데 Kalman 필터가 사용되었다. 자동시각 검사시스템의 실험은 프로젝터를 이용한 수작업 측정의 정확도 수준을 보여준다.

• 한국압력기기공학회 논문집
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• 제7권3호
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• pp.8-14
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• 2011

The clogging of the flow area at the tube support plates(TSPs), especially at the upper TSPs results in the water level oscillation of a steam generator during normal operation. A reduction of the TSP flow area causes to increase in pressure drop within the two-phase flow zone, which destabilizes the boiling flow through the tube bundle. This phenomenon was occasionally observed at a few domestic and foreign nuclear power plants. One of the methods for defining the flow area clogging is visual inspection, which is the most effective inspection method. The results of the visual inspection for TSPs' flow area are clogging images on TSPs' quartrefoil lobes. These images are complexly distorted due to lens aberration and external factors like the distance to a subject and angle etc. In this work, we developed the analysis algorithm for clogging image of the TSP flow area of steam generators. For this purpose, we designed an image verification device applicable to the camera employed in the field for visual inspection and then, we demonstrated the validity of image analysis algorithm by using this device and commercial autoCAD program.

• 한국측량학회지
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• 제39권2호
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• pp.103-111
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• 2021

MMS (Mobile Mapping System) is being used for HD (High Definition) map construction because it enables fast and accurate data construction, and it is receiving a lot of attention. However, research on the use of MMS in the construction field is insufficient. In this study, road surveying and inspection of construction structures were performed using MMS. Through data acquisition and processing using MMS, point cloud data for the study site was created, and the accuracy was evaluated by comparing with traditional surveying methods. The accuracy analysis results showed a maximum of 0.096m, 0.091m, and 0.093m in the X, Y, and H directions, respectively. Each RMSE was 0.012m, 0.015m, and 0.006m. These result satisfy the accuracy of topographic surveying in the general survey work regulation, indicating that construction surveying using MMS is possible. In addition, a 3D model was created using the design data for the underpass road, and the inspection was performed by comparing it with the MMS data. Through inspection results, deviations in construction can be visually confirmed for the entire underground roadway. The traditional method takes 6 hours for the 4.5km section of the target area, but MMS can significantly shorten the data acquisition time to 0.5 hours. Accurate 3D data is essential data as basic data for future smart construction. With MMS, you can increase the efficiency of construction sites with fast data collection and accuracy.

• 대한안전경영과학회지
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• 제25권3호
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• pp.55-62
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• 2023

Public institutions have a responsibility to ensure the safety of their employees and the public. One way to do this is to implement a systematic safety inspection system based on risk assessments and continuous improvements. This study developed a systematic safety inspection system for public institutions that are ordered construction projects. The proposed system in this study consists of a three-step process: (1) developing safety grade evaluation tables, (2) preparing and conducting safety inspections, and (3) evaluating and improving safety management grades. The first step is to develop safety grade evaluation tables by analysis and diagnosis of the construction site's work type, disaster statistics, and related laws. The second step is to conduct safety inspections using the developed evaluation tables. The third step is to determine the safety management grade based on the results of the safety inspection, and to improve risk factors found during the safety evaluation. The proposed system was implemented in highway construction projects carried out by public institutions. The results showed that the proposed system has two major effects: (1) reducing accident-related deaths and injuries, (2) improving safety management levels by continuous evaluation and improvement. The proposed system can be utilized in construction projects ordered by public institutions to improve the level of occupational safety and health.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2005년도 공동추계학술논문발표회 논문집
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• pp.117-125
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• 2005

• 한국산학기술학회논문지
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• 제15권4호
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• pp.2324-2329
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• 2014

차내 연산 열차제어시스템은 검수고에 지상신호장치가 설치되지 않은 경우 본선 및 시험선으로 출고하였을 때에만 점검이 가능하여 업무의 효율성 저하 및 안전운행에 위해요인으로 작용한다. 열차의 운행 전 또는 운행 후 안전운행 확보를 위한 측면에서 차상 지상신호 설비 간 인터페이스 동작시험이 반드시 필요하다. 본 논문에서는 지상에서 차상시스템으로 전송되는 가상의 열차 운행정보에 따른 열차 차상신호 장치의 동작상태 확인과 차상에서 지상시스템으로 전송되는 열차 상태정보에 대한 실시간 자동 분석을 기반으로 한 열차 차상신호 인터페이스 검사시스템을 제안하여 대전도시철도 판암기지에 구축, 차상 지상신호 간 인터페이스시험 알고리즘을 검증하였다. 이에 따라 차상 열차제어시스템 점검을 위해 약 30분간의 시험선 운행이 불필요하여 업무의 효율성을 크게 향상시켰다.