• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.887-894
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• 2009

There is no standard rule for the test of the railway abrasion measurement system composed of the line laser and the camera. This paper is proposed of the method to estimate the performance of the railway abrasion measurement system. The performance estimation is achieved by the quantitative analysis parameters such as MTF, NPS and DQE.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1023-1024
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• 2008

This paper proposes a pedestrian counting system using line laser. By using a line laser and IR filter, the shapes of pedestrians are easily obtained without complex preprocessing. Also, the directions of pedestrians were able to distinguish by employing gradient information. In the experiment, the proposed method successfully counted the number of people with accuracy of about 97% and with processing time of 24ms per frame.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.349-352
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• 2007

자율 센서 네트워크에서 센서 노드가 자율 주행하기 위해서 주행 경로 상의 장애물을 회피해야 한다. 이를 위해서 저렴하고 동적인 상황에서도 효과적인 장애물 탐지 비전 센서를 구현하였다. 이 연구에서는 Structured Light방식을 이용하였으며. Structured Light로는 라인 패턴의 적외선 레이저를 사용하였고 카메라에 적외선 필터를 장착하여 빛의 효과에 둔감하게 하였다. 값과 시간에 따른 2차 Thresholding으로 노이즈를 제거하였다. 실험 결과 센서 노드를 기준으로 한 2D 좌표계에서 최대 10mm의 오차로 장애물의 X, Y좌표를 찾을 수 있었으며 비전 센서의 프로그램은 객체화 하여 센서 노드 프로그램과 연동되어 장애물의 정보를 Localize와 Map building에 사용 할 수 있도록 제공한다.

• Spatial Information Research
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• v.17 no.3
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• pp.381-387
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• 2009

This study investigates the use of geomorphic analysis results obtained from high-resolution LiDAR-derived DEM. The results of analysis, slope angle and eigenvalue ratio (ER) were derived from the DEM for 3 landslide and 1 non-landslide occurrence area. Results of this study highlighted the importance of geomorphic analysis in characterizing landslide feature as well as the various contents in their future occurrence and activity. The relationship between the results of geomorphic analysis and landslides are well expressed in this paper.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.110.2-110.2
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• 2016

4세대 방사광가속기는 0.1nm급 X-선 자유전자레이저(X-ray Free Electron Laser : XFEL) 광원을 빔라인 사용자들에게 제공하기 위하여 2011년 건설을 시작하였고, 2015년부터 장치를 설치하기 시작했으며 현재 건설 완료단계에 이르러 있다. 이 장치에서 진공시스템은 10-11 mbar의 초고진공이 요구되는 전자빔 발생장치인 RF Gun을 포함하는 입사장치구간(Injector)과 전체길이 800 m에 이르는 전자빔을 가속시키는 선형가속기구간(Linac) 그리고 결맞음 방사광을 발생시키는 언듈레이터구간으로 나눌 수 있다. 본 논문에서는 각 구간별 진공시스템에 대한 건설 현황에 대하여 보고하고자 한다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.235-235
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• 2012

Reduced graphene oxide (rGO) 물질을 사용하여 전계효과 트랜지스터를 제작하였고 이의 광전기적 특성을 펄스 레이저와 진공 저온 측정을 통하여 분석하였다. 이를 통하여 rGO 소자의 광소자로써의 이용 가능성에 대하여 고찰하였다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.5
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• pp.567-577
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• 2016

The hutches which are installed in the beamline are largely classified into two, i.e XPP (X-ray pump probe) and CXI (Coherent X-ray image). Laser room is installed on the hutch and provides laser to XPP and CXI simultaneously. And two hutches have heavy crane to install some optics equipments. Safety and reliability of hutch structures should be taken into account for the precise operating of the laser facilities, so vibration analysis is essential to do this. The main purpose of vibration analysis is to install hutch structures with large stiffness. We have changed materials specification several times to install hutch structures having strong stiffness. Now hutch structures were installed and checked vibration status at laser room and XPP hutch. The results of laser table and robot arm satisfy vibration criteria. This paper explains about the design and vibration analysis of hutch structures.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.2
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• pp.85-91
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• 2014

The objective of the research is to automatically recognize railway objects from MLS data in which 9 key objects including terrain, track, bed, vegetation, platform, barrier, posts, attachments, powerlines are targeted. The proposed method can be divided into two main sub-steps. First, multi-scale contextual features are extracted to take the advantage of characterizing objects of interest from different geometric levels such as point, line, volumetric and vertical profile. Second, by considering contextual interactions amongst object labels, a contextual classifier is utilized to make a prediction with local coherence. In here, the Conditional Random Field (CRF) is used to incorporate the object context. By maximizing the object label agreement in the local neighborhood, CRF model could compensate the local inconsistency prediction resulting from other local classifiers. The performance of proposed method was evaluated based on the analysis of commission and omission error and shows promising results for the practical use.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.27-29
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• 2007

The visual implementation of 3-dimensional national environment is focused by the requirement and importance in the fields such as, national development plan, telecommunication facility deployment plan, railway construction, construction engineering, spatial city development, safety and disaster prevention engineering. The currently used DEM system using contour lines, which embodies national geographic information based on the 2-D digital maps and facility information has limitation in implementation in reproducing the 3-D spatial city. Moreover, this method often neglects the altitude of the rail way infrastructure which has narrow width and long length. There it is needed to apply laser measurement technique in the spatial target object to obtain accuracy. Currently, the LiDAR data which combines the laser measurement skill and GPS has been introduced to obtain high resolution accuracy in the altitude measurement. In this paper, we first investigate the LiDAR based researches in advanced foreign countries, then we propose data a generation scheme and an algorithm for the optimal manage and synthesis of railway facility system in our 3-D spatial terrain information. For this object, LiDAR based height data transformed to DEM, and the realtime unification of the vector via digital image mapping and raster via exactness evaluation is transformed to make it possible to trace the model of generated 3-dimensional railway model with long distance for 3D tract model generation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.985-993
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• 2001

Neural networks are shown to be effective in being able to distinguish incomplete penetration-like weld defects by directly analyzing the plasma which is generated on each impingement of the laser on the materials. The performance is similar to that of existing methods based on extracted feature parameters. In each case around 93% of the defects in a database derived from 100 artificially produced defects of known types can be placed into one of two classes: incomplete penetration and bubbling. The present method based on classification using plasma is faster, and the speed is sufficient to allow on-line classification during data collection.