• 한국도로학회논문집
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• 제17권1호
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• pp.17-24
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• 2015

PURPOSES : Recently, crack, rutting, and stripping problems from the surface of asphalt pavements in National highway are observed and they affect the drivers to feel uncomfortable on the road. Surface treatments are recommended to use in distressed pavements due to cost-effective, and improvement of surface performance. The purpose of this study is to evaluate the performance of micro-surfacing and polymer slurry seal treatments for distressed asphalt pavements. METHODS : Surface conditions and friction resistance are evaluated for asphalt pavements treated with micro-surfacing and polymer slurry seal mixes in National highway 30 line and 34 line. Visual observation is conducted and surface performance is measured by PES (Performance Evaluation Surveyor) in terms of crack ratio, rutting and IRI(International Roughness Index). BPN(British Pendulum Number) is measured by BPT(British Pendulum Tester) to evaluate the friction resistance in the field. RESULTS : The surface evaluation results are presented for asphalt pavement treated with micro-surfacing and polymer slurry seal treatments in National highway 30 line and 34 line. Based on the visual observation, micro-surfacing and polymer slurry seal treatments show better improvements in terms of cracks and stripping. Based on the surface conditions measured by PES vehicle, the surface performance of micro-surfacing treatments improves from 53.3% to 54.2% and the surface performance of polymer slurry seal treatments improves from 21.6% to 59.7%. However, the friction resistance of both micro-surfacing and polymer slurry seal treatments decreases from 2.5% to 6.7%. Further, it should be verified to produce the surface exposed with aggregates during the construction process of both treatment methods in the field. CONCLUSIONS : Based on the performance evaluation results in the filed, the surface performance of asphalt pavement treated with micro-surfacing and polymer slurry seal treatments improves from 21.6% to 59.7%. While, the friction resistance of asphalt pavement treated with micro-surfacing and polymer slurry seal treatments does not improve. It can be concluded that current micro-surfacing and polymer slurry seal treatments would improve surface performance but would not improve the friction resistance.

• 한국철도학회논문집
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• 제18권1호
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• pp.63-70
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• 2015

궤도틀림은 철도차량의 주행안전성과 승차감에 영향을 미칠 뿐만 아니라 유지보수와 밀접한 관계가 있다. 본 논문에서는 경부고속철도 개통 이후 경부고속선 구간에서 검측된 궤도틀림에 대하여 통계분석을 수행하였다. 우선, 궤도틀림 검측에 사용된 검측차(EM120)의 검측특성, 즉 현정시법 검측원리를 사용하는 경우에 대한 파장대역별 전달함수 특성을 조사하였다. 고저틀림과 방향틀림에 대한 파장의 분포 특성 분석결과에 의하면, 단파장의 파장대역의 분포비율이 상당히 높았으며 파장이 길어질수록 발생빈도는 감소하는 경향을 보였다. EN규정에서 규정하고 있는 파장대역별로 구분하여 분포 현황을 조사한 결과는 D1 영역의 분포비율이 대부분을 차지하고 있는 것으로 파악되었다. 또한, 궤도틀림 항목별로 궤도틀림 크기에 따른 분포 특성을 조사하였으며, 궤도틀림의 크기가 증가할수록 발생빈도는 급격히 감소하는 경향을 보였다. 이러한 궤도틀림 분포 특성에 대한 조사결과는 궤도틀림 유지보수 계획수립 및 궤도틀림 기준설정을 위한 기초자료로 유용하게 사용될 수 있을 것으로 예상된다.

• 융합정보논문지
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• 제10권10호
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• pp.123-127
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• 2020

야간 중대형 산불의 전체적인 화선정보를 얻기 위하여 누락되는 산불에 대한 반복적인 임무비행과 임무수행 종료 후 획득되는 정사영상 정합에 대한 소요시간을 줄이기 위하여 실시간 동영상으로 산불발생 여부를 판단하고 드론의 위치와 영상카메라의 각도정보, 지도상의 고도정보를 활용하여 판단된 산불위치를 계산하여 지도에 도시할 수 있는 지상통제시스템을 개발하였다. 개발된 기능의 신뢰성을 검증하기 위하여 비행고도 별, 영상카메라의 지향하는 위치정보의 오차거리를 측정하였으며, 신뢰할 수 있는 범위내의 위치정보를 지도에 표시하였다. 본 논문에 개발된 기능으로 다수의 산불 발생위치를 실시간 식별이 가능하므로 산불 진화대책 수립을 위한 전체적인 화선정보를 보다 신속하게 획득할 수 있을 것으로 예상된다.

• 한국철도학회논문집
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• 제14권3호
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• pp.222-227
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• 2011

드로퍼는 전차선로에서 여러형태의 클램프로 취부되어 전차선이 수평으로 유지하도록 지지하고, 판토그라프가 통과할 때 굽힘에 대한 기계적 응력에 영향을 받는다. 고속선용 드로퍼의 파단 원인을 조사하기 위해, 이론적 분석 및 시험을 실행하였다. 본 논문에서 사전이도에 의한 드로퍼의 정적 하중을 계산하였고, 시험에서 측정된 값과 유사하였다. 드로퍼 와이어의 파단원인을 분석하기 위해 현장에서 파단된 시료는 SEM 분석을 하였고, 새 시료도 일부 병행하며 시행하였다. 마지막으로, 고속열차가 300km/h로 통과할 때 드로퍼에 대한 동적 하중의 변화를 측정하였다. 기계적 하중이 반복적으로 발생될 때, 드로퍼 와이어는 피로에 의해 파단될 것이다. 이 결과는 고속전차선로 유지보수의 특별 관리와 드로퍼의 수명평가를 하는데 활용될 수 있을 것이다.

• 전자공학회논문지SC
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• 제46권2호
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• pp.22-27
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• 2009

본 논문에서는 LCD 구동 모듈 PCB의 기능 검사를 위한 자동 검사 시스템인 EVT (Emulated Vision Tester)를 제안하고 구현하였다. 기존의 대표적인 자동검사 방법으로는 전기적 검사나 영상기반 검사방식이 있으나 전기적 검사만으로는 Timing이 주요한 변수가 되는 LCD 장비에서는 검출할 수 없는 구동불량이 존재하며 영상기반 검사는 영상획득에 일관성이 결여되거나 Gray Scale의 구분이 불명확하여 검출결과의 재현성이 떨어진다. EVT 시스템은 Pattern Generator에서 인가된 입력 패턴 신호와 구동 모듈을 통한 후 출력되는 디지털 신호를 직접 비교하여 패턴을 검사하고 아날로그 신호 (전압, 저항, 파형)의 이상 여부도 신속 정확하게 검사할 수 있는 하드웨어적인 자동 검사 방법이다. 제안된 EVT 검사기는 높은 검출 신뢰도와 빠른 처리 속도 그리고 간결한 시스템 구성으로 원가 절감 및 전공정 검사 자동화의 실현을 가능케 하는 등 많은 장점을 가진다.

• Structural Monitoring and Maintenance
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• 제6권4호
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• pp.365-387
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• 2019

This study aims to provide useful information on the fatigue assessment of a top-tensioned riser (TTR) subjected to vortex-induced vibration (VIV) by performing parametric study. The effects of principal design parameters, i.e., riser diameter, wall thickness, water depth (related to riser length), top tension, current velocity, and shear rate (or shear profile of current) are investigated. To prepare the base model of TTR for parametric studies, three (3) riser modelling techniques in the OrcaFlex were investigated and validated against a reference model by Knardahl (2012). The selected riser model was used to perform parametric studies to investigate the effects of design parameters on the VIV fatigue damage of TTR. From the obtained comparison results of VIV analysis, it was demonstrated that a model with a single line model ending at the lower flex joint (LFJ) and pinned connection with finite rotation stiffness to simulate the LFJ properties at the bottom end of the line model produced acceptable prediction. Moreover, it was suitable for VIV analysis purposes. Findings from parametric studies showed that VIV fatigue damage increased with increasing current velocity, riser outer diameter and water depth, and decreased with increasing shear rate and top tension of riser. With regard to the effects of wall thickness, it was not significant to VIV fatigue damage of TTR. The detailed outcomes were documented with parametric study results.

• FOCUS: LIFE SCIENCE
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• 제1호
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• pp.1.1-1.4
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• 2024

This article provides comprehensive guidance on the maintenance, cleaning, regeneration, and storage of silica-based HPLC (High-Performance Liquid Chromatography) columns. The general considerations emphasize the importance of using in-line filters and guard cartridges to protect columns from blockage and irreversible sample adsorption. While these measures help, contamination by strongly adsorbed sample components can still occur over time, leading to an increase in back pressure, loss of efficiency, and other issues. To maximize column lifetime, especially with UHPLC (Ultra-High Performance Liquid Chromatography) columns, it is advisable to use ultra-pure solvents, freshly prepared aqueous mobile phases, and to filter all samples, standards, and mobile phases. Additionally, an in-line filter system and sample clean-up on dirty samples are recommended. However, in cases of irreversible compound adsorption or column voiding, regeneration may not be possible. The document also provides specific recommendations for column cleaning procedures, including the flushing procedures for various types of columns such as reversed phase, unbonded silica, bonded normal phase, anion exchange, cation exchange, and size exclusion columns for proteins. The flushing procedures involve using specific solvents in a series to clean and regenerate the columns. It is emphasized that the flow rate during flushing should not exceed the specified limit for the particular column, and the last solvent used should be compatible with the mobile phase. Furthermore, the article outlines the storage conditions for silica based HPLC columns, highlighting the impact of storage conditions on the column's lifetime. It is recommended to flush all buffers, salts, and ion-pairing reagents from the column before storage. The storage solvent should ideally match the one used in the initial column test chromatogram provided by the manufacturer, and column end plugs should be fitted to prevent solvent evaporation and drying out of the packing bed.

• 한국측량학회지
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• 제31권4호
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• pp.269-275
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• 2013

최근 들어 모바일 단말기를 휴대하고 이동하는 사용자에게 경로안내 및 주변 위치정보 안내와 같은 개인화된 서비스가 가능해졌다는 점에서 보행자용 도로망의 중요성이 커지고 있다. 한편, 전국단위 도로망 신규 구축과 갱신에 많은 비용이 소요된다는 점은 활성화의 제약조건으로 작용하고 있어 래스터 데이터를 기반으로 한 보행자용 도로망 추출 알고리즘을 적용한 자동 생성 방안이 필요한 상황이다. 그러나 생성된 도로망은 불필요한 결절점이 다수 포함되어 경로 안내 시 과도한 방향전환을 야기하고 데이터 용량 증가를 초래하는 등 유지관리 차원에서의 비효율이 발생한다. 본 연구에서는 이를 제거하기 위해 Douglas-Peucker 알고리듬 적용 과정에서 수치지도 도로의 속성정보를 이용하여 각 선형 객체별로 적합한 임계값을 부여함으로써 선형단순화의 효과는 극대화하고 실제 도로의 형태를 왜곡하지 않도록 최적의 임계값을 자동 선정하였다. 실험 대상 지역의 보행자용 도로망에 적용한 결과 결절점 감소율과 위치정확도 측면에서 제안된 방법이 자동 선형단순화에 적합하다는 결과를 얻을 수 있었다.

• Molecules and Cells
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• 제41권5호
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• pp.413-422
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• 2018

Soybean transgenic plants with ectopically expressed AtABF3 were produced by Agrobacterium-mediated transformation and investigated the effects of AtABF3 expression on drought and salt tolerance. Stable Agrobacterium-mediated soybean transformation was carried based on the half-seed method (Paz et al. 2006). The integration of the transgene was confirmed from the genomic DNA of transformed soybean plants using PCR and the copy number of transgene was determined by Southern blotting using leaf samples from $T_2$ seedlings. In addition to genomic integration, the expression of the transgenes was analyzed by RT-PCR and most of the transgenic lines expressed the transgenes introduced. The chosen two transgenic lines (line #2 and #9) for further experiment showed the substantial drought stress tolerance by surviving even at the end of the 20-day of drought treatment. And the positive relationship between the levels of AtABF3 gene expression and drought-tolerance was confirmed by qRT-PCR and drought tolerance test. The stronger drought tolerance of transgenic lines seemed to be resulted from physiological changes. Transgenic lines #2 and #9 showed ion leakage at a significantly lower level (P < 0.01) than ${\underline{n}}on-{\underline{t}}ransgenic$ (NT) control. In addition, the chlorophyll contents of the leaves of transgenic lines were significantly higher (P < 0.01). The results indicated that their enhanced drought tolerance was due to the prevention of cell membrane damage and maintenance of chlorophyll content. Water loss by transpiration also slowly proceeded in transgenic plants. In microscopic observation, higher stomata closure was confirmed in transgenic lines. Especially, line #9 had 56% of completely closed stomata whereas only 16% were completely open. In subsequent salt tolerance test, the apparently enhanced salt tolerance of transgenic lines was measured in ion leakage rate and chlorophyll contents. Finally, the agronomic characteristics of ectopically expressed AtABF3 transgenic plants ($T_2$) compared to NT plants under regular watering (every 4 days) or low rate of watering condition (every 10 days) was investigated. When watered regularly, the plant height of drought-tolerant line (#9) was shorter than NT plants. However, under the drought condition, total seed weight of line #9 was significantly higher than in NT plants (P < 0.01). Moreover, the pods of NT plants showed severe withering, and most of the pods failed to set normal seeds. All the evidences in the study clearly suggested that overexpression of the AtABF3 gene conferred drought and salt tolerance in major crop soybean, especially under the growth condition of low watering.

• 한국환경복원기술학회지
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• 제4권3호
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• pp.10-18
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• 2001

The existing measurement system to ground-surface displacement survey of the slope has been including the hazard for the measure in site and the difficulty for install, maintenance and control of expensive instruments, which are impossible of whole survey on the slope surface. To overcome of those defects, Softcopy Photogrammertry method is used, which can measure displacement of ground-surface on the slope and structure deformation vectors. Recently, the survey methods applying the advantages of Photogrammetry and Digital Photogrammetry Survey are widely used. In this study, therefore, the development and application of the new instrument mechanism on the the site example are studied. Through the application of Softcopy Photogrammetry, the 3-D data of ground surface on the dangerous slope could be effectively obtained at the long distance, which are obtained through the reform process of contour line. Those are different to the results of the Close-Range Photogrammetry analysis. In ground instrumentation parts, the new practical system shall be the technical base to improve of the instrument machine as well as can be widely applied in civil engineering and others branch.