• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.3
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• pp.9-23
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• 2015

A lane change maneuver which has a high driver cognitive workload and skills sometimes leads to severe traffic accidents. In this study, the Advanced Lane Change Assist System (ALCAS) was developed to assist with the automatic lane changes in merging sections which is mainly based on an automatic control algorithm for detecting an available gap, determining the Optimal Lane Change Start Point (OLCSP) in various traffic conditions, and positioning the merging vehicle at the OLCSP safely by longitudinal automatic controlling. The analysis of lane change behavior and modeling of fundamental lane change feature were performed for determining the default parameters and the boundary conditions of the algorithm. The algorithm was composed of six steps with closed-loop. In order to confirm the algorithm performance, numerical scenario tests were performed in various surrounding vehicles conditions. Moreover, feasibility of the developed system was verified in microscopic traffic simulation(VISSIM 5.3 version). The results showed that merging vehicles using the system had a tendency to find the OLCSP readily and precisely, so improved merging performance was observed when the system was applied. The system is also effective even during increases in vehicle volume of the mainline.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1134-1138
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• 2010

호소의 수질오염 문제를 해결하기 위해선 우선 소하천에서 강우유출에 의한 비점오염물질이 어디서 얼마나 발생하는지에 대한 정량적인 조사가 필요하다. 그러나 유역의 오염원에 대한 정량적인 조사가 이루어지려면 많은 비용과 시간 그리고 노력이 필요하다. 따라서 본 연구에서는 대청호 상류유역의 소하천인 안내천을 대상으로 강우유출수 조사를 실시하고, 높은 예측 정확성 때문에 세계적으로 널리 쓰이고 있는 Long-Term Hydrologic Impact Assessment(L-THIA)을 이용하여 실측데이터와 L-THIA 모델의 결과를 비교하였다. 안내천의 유역면적은 16.5 $km^2$로 유역의 약 69.5%가 산림, 농업 및 초지지역이 25.3% 그리고 주거지역이 2.6%로 조사되었다. 수질분석을 위하여 자동수질시료채취기(ISCO sampler 6712)를 설치하여 시간단위의 시료를 채취한 뒤 수질농도를 측정하였다. 수질항목은 유기물질인 $BOD_5$, TOC, T-N, T-P 항목에 대하여 수질오염 공정시험법으로 분석하였다. WHAT 시스템을 이용하여 분리된 직접유출량은 315.5~161,835.1 $m^3$의 범위로 나타났다. 직접유출량을 이용하여 산정한 유역의 EMC 농도는 안내천 유역의 $EMC_{BOD}$는 1.0~2.4 mg/L, $EMC_{TOC}$는 1.429~5.491 mg/L, $EMC_{COD}$는 2.2~10.2 mg/L, $EMC_{TN}$은 2.906~10.864 mg/L, $EMC_{TP}$는 0.029~0.285 mg/L의 범위를 보였다. 또한 실측된 유량과 농도를 이용하여 산정한 오염부하는 안내천 유역이 $BOD_5$ 37.9~390.9 g, $COD_{Mn}$ 0.8~1,657.5 g, TOC 0.54~791.83 g, T-N 0.968~1,758.174 g, T-P 0.011~42.139 g의 범위로 나타났다. L-THIA 모델을 이용하여 직접유출량의 산정된 결과와 실측 결과를 비교 분석한 결과 결정계수와 유효지수가 0.95와 0.93으로 높게 나타나 대청호 상류유역에서 발생하는 유출량을 모의하는데 적절할 것으로 판단된다. 토지이용도와 토양도 그리고 일 강우자료만으로 구축되는 L-THIA 모델을 이용하여 대청호 상류의 소하천 유역에 대하여 비점오염원 유출특성을 해석하는 것이 가능 할 것으로 판단된다.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.802-810
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• 2006

For a thorough train control, the precise train position detection is necessarily required. The widely used current way for train position detection is the one of using track circuits. The track circuit has a simple structure, and has a high level of reliability. However trains can be detected only on track circuits, which have to be installed on all ground sections, and much amount of cost for its installation and maintenance is needed. In addition, for the track circuit, only discontinuous position detection is possible because of the features of the closed circuit loop configuration. As the recent advances in telecommunication technologies and high-tech vehicle-based control equipments, for the train position detection, the method to detect positions directly from on trains is being studied. Vehicle-based position detection method is to estimate train positions, speed, timing data continuously, and to use them as the control information. In this paper, the features of GPS navigation and DR navigation are analyzed, and the navigation filters are designed by constructing vehicle-based train position detection method by combining GPS navigation and DR navigation for their complementary cooperation, and by using kalman filter. The position estimation performance of the proposed method is also confirmed by simulations.

• The Mathematical Education
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• v.25 no.2
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• pp.1-11
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• 1987

호주 정부는 1988년이 유럽인의 호주 이민 200주년이 되는 것을 기념하여 대대적인 행사를 추진하고 있으며 이 행사의 일환으로 1988년 7월 9일 부터 21일 까지 "제29회 국제수학경시대회"를 개최할 예정이다. 이 대회의 주최측에서는 우리나라에도 중ㆍ고등학생의 참가를 요청하였다. 필자들은 이 대회에 우리나라 대표를 파견할 경우를 대비하여 그 동안 IMO에 관한 여러가지의 정보를 조사한 바 대회 참가 여부에 대하여 다음과 같은 결론을 얻었다. 1. 참가의 필요성 (1) 중ㆍ고등 학생들에게 수학에 관한 관심을 높히고, 나아가서는 모든 국민에게 과학적인 사고의 향상을 기대한다. (2) 궁극적으로 수학을 위시한 기초 과학, 응용 과학에 대한 전반적인 관심도가 높아져서 수학자 및 과학자의 저변 확대를 기대할 수 있고, 특히 수리적인 사고력이 뛰어난 사람을 조기에 찾아내어 2000년대의 과학 선진국 건설에 중추적인 역할을 맡을 인력자원을 확보할 수 있다. (3) 현재 중ㆍ고등학교 수학 교육이 계산 위주, 암기 위주로 되어 있고, 학력 고사를 위시하여 많은 시험이 객관적으로 사고력 배양이 고려되지 않고 있다. IMO 참가자를 선발하기 위하여 거국적인 경시 대회를 개최한다면 자연히 이를 대비한 주관식 문제를 접할 기회를 가지게 되고, 따라서 수학 교육의 목적중의 하나인 사고력 배양을 기대할 수 있다. (4) 우리 국민의 조직적인 사고력과 과학적인 두뇌를 세계적으로 자랑할 수 있는 좋은 기회이다. (5) 자라나는 새싹들에게 국제 대회의 기회를 주므로써 장차 우리나라의 수학 수준을 국제적으로 높힐 수 있는 기틀을 마련한다. 2. 우리나라 학생이 IMO에 참가하여 우수한 성적을 거둘수 있는지 여부 (1) 절대적으로 있다. 참가하는 첫 해부터 상위권에 들어갈 것이다. 우리의 중ㆍ고등학교 수학 수준이 세계 평균보다 약간 높다. 그리고 몇 년의 경륜을 쌓는다면 세계 1, 2위에 도전 할 수 있다. 이것은 올림픽이나 아시아 게임에 기울이는 비용의 몇 만분의 일을 가지고, 그 보다 훨씬 높은 수준의 국력을 과시할 수 있는 기회이다. (2)매년 그 성적이 올라가리라 생각한다. 예로서 우리와 비교하여 형편없는 국력을 가진 몽고가 8년간 꼴찌를 하다 1894년 대회에서 참가국 33개국 중에서 10위를 차지하였다. 미국은 참가 첫 해부터 2위를 하였고, 11년 동안 1위 2번, 2위 4번을 하였으며, 매번 5위 이내에 머물렀다. (3) 월남은 그 나라의 사정때문인지 자주 참가하지 못하였다. 그러나 참가할 때마다 항상 상위권에 속하였다. 이것은 월남 국민들의 수학에 관한 관심도를 나타낸다고 본다. 우리 국민도 월남 국민에 못지 않으리라 생각한다. 3. 한국수학교육학회가 주관하여 뛰어난 학생을 선발 할 수 있는지 여부 (1) 있다. (2)한국수학경시대회 (KMO) 위원회를 한국수학교육학회 산하에 구성하여 KMO를 주관하게 하고, 또 국내의 여러 수학경시대회에서 우수한 성적을 나타낸 학생중에서 일정한 인원(50명 정도)을 선발하여 특별히 선정된 훈련팀으로 하여금 조직적인 훈련을 시킨다면 된다. 4. 기타 (1) 과거 어떠한 형태로든 국제 대회에 참가한 경력은 전혀 없다. (2) 1960년대에 서울대학교 공과대학 학생회에서 주최한 수학경시대회가 있었으나 보잘것이 없었고, 현재에도 각 시도별 또는 대학주관의 경시대회가 있으나 거국적인 호응을 받지 못했다. 물론 국제 대회에 참석시키는 것은 엄두도 내지 않았다.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.135-144
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• 2016

It is essential to lighten the weight of switch girders in order to reduce their costs of manufacturing and make it easier to use them in construction. Lightening the weight of switch is also important to the Maglev 3-way switches system, however, the design variables should be considered very carefully if lightening is to be applied to the system, because these variables are vitally related to the levitation stability. Because Urban Maglev trains have a structure in which train bogie wraps around the guiderail, the adjustment of a girder's height is a possible way to reduce the weight. The safety of the application of this concept is ensured by repeated experiments in a test bed, however, due to a lack of space and budget limits, the design parametric study for the system model can substitute for actual application. The purpose of this paper is to study the design parameters that are concerned with levitation stability while a Maglev train is running on the Maglev 3-way system depending on the weight of the switch girders. In this study, switch girder weight is reduced by adjustment of girder height and girders are and modeled as a flexible body. The effect of the adjustment of girder height on the levitation stability can be analyzed by comparing the velocity of the train when it passes the switch girders, with the lateral gap, and the levitation gap which are obtained from the co-simulation of the Maglev train's dynamics model and flexible switching system. The results of this research will be used to design a Maglev switch.

• Geotechnical Engineering
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• v.5 no.1
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• pp.7-18
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• 1989

In pile load tests on end bearing piles, generally, it is not possible to continue loading to the ultimate load. Thus, the concept of yield load has been introduced for determining design loads Iron the pile load test records. The conventional rules to determine the yield load were not available for evaluation on pile load test records obtained in 6 fields nearby westers 8r Southern Coasts in Korea. A new rule 9.as presented to determine easily the yield load, based on investigations on the pile load test records. The yield load of piles is determined at the infiection point on semi-logarithmic coordinates (P-logS), in which load is plotted in normal scale and settlement is plotted in logarithmic scale. This method may not only save much costs and times but also present safe luorking circumstances for pile load tests in field. It was found that the yield load represented the elastic limit of the pile load-settlement behalf.iota. The ultimate load, which is given at 25.4mm settlement on pile head, was 1.5 times of the yield load. The allowable long-term and short-term load capacities were, respectively, 50% and 75% of the yield load. The safety factors to get the allowable pile capacity were obtained as 2.0~4.0 for the equations to predict the static pile capacity.

• Korean Journal of Construction Engineering and Management
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• v.1 no.1 s.1
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• pp.87-94
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• 2000

Crack sealing, a routine and necessary part of pavement maintenance, is a dangerous, costly, and labor-intensive operation. Within the North America, about ${\$}200$ million is spent annually on crack sealing, with the Texas Department of Transportation (TxDOT) spending about ${\$}7$ million annually (labor alone accounts for over 50 percent of these costs). Prompted by concerns of safety and cost, the University of Texas at Austin, in cooperation with TxDOT and the Federal Highway Administration (FHWA) has developed a unique computer-guided Automated Road Maintenance Machine (ARMM) for pavement crack sealing. In 1999, successful field tests have been undertaken in 8 States around the U.S. This paper first describes significance of the automated crack sealing and technical advances in automated crack sealers including the ARMM, developed in the U.S. It then discusses the ARMM's field implementation and performance evaluation results, and improvements and modifications suggested through the technology evaluation during the field trials. Current research efforts and future work plans in its further development are also presented in this paper.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.1
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• pp.33-39
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• 2010

Printing technologies have been indicated as alternative methods for patterning conductive, semi-conductive or insulative materials on account of their low-cost, large-area patternability and pattern flexibility. For application of the printing technologies in manufacture of semiconductor or display modules, ink or paste composed of nanoparticles, solvent and additives are basically needed. Here, we report recent advances in eco-friendly nano-ink technology for semiconductor and display technology. Then, we will introduce an eco-friendly ink formation technology developed in our group with an example of manufacturing $SiO_2$ nanopowders and inks. We tried to manufacture ultrafine $SiO_2$ nanoparticles by applying a low-temperature synthetic method, and then attempted to fabricate the printed $SiO_2$ film onto the glass substrate to see whether the $SiO_2$ nanoparticles are feasible for the printing or not. Finally, the electrical characteristics of the films were measured to investigate the effect of the manufacturing parameters.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.2
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• pp.29-35
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• 2017

In this paper, we investigated a manufacturing process of metal micro-wire interconnection on submillimeter diameter catheter. Over the years, flexible electronic researches have focused on flexible plane polymer substrate and micro electrode manufacturing on its surface. However, a curved polymer substrate, such as catheter, is very important for medical application. Among many catheters, importance of submillimeter diameter steerable catheter is increasing to resolve the several limitations of neurosurgery. Steering actuators have been researched for realizing the steerable catheter, but there is no research about practical wiring for driving these actuators. Therefore we developed a new manufacturing process for metal micro-wire interconnection on submillimeter diameter catheter. We designed custom jigs for alignment of the metal micro-wires on the submillimeter diameter catheter. An UV curing system and commercial products were used to reduce the manufacturing time and cost; Au micro-wire, UV curable epoxy, UV lamp, and submillimeter diameter catheter. The assembled catheter was characterized by using an optical microscope, a resistance meter, and a universal testing machine.

• Journal of the Institute of Convergence Signal Processing
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• v.18 no.2
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• pp.55-61
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• 2017

In radio astronomy, high-capacity HDDs are being used to save huge amounts of HDDs in order to record the observational data. For VLBI observations, observational speeds increase and huge amounts of observational data must be stored as they expand to broadband. As the HDD is frequently used, the number of failures occurred, and then it takes a lot of time to recover it. In addition, if a failed HDD is continuously used, observational data loss occurs. And it costs a lot of money to buy a new HDD. In this study, we developed the integrity verification system of the Serial ATA HDD using FirmOS. The FirmOS is an OS that has been developed to function exclusively for specific purposes on a system having a general server board and CPU. The developed system performs the process of writing and reading specific patterns of data in a physical area of the SATA HDD based on a FirmOS. In addition, we introduced a method to investigate the integrity of HDD integrity by comparing it with the stored pattern data from the HDD controller. Using the developed system, it was easy to determine whether the disk pack used in VLBI observations has error or not, and it is very useful to improve the observation efficiency. This paper introduces the detail for the design, configuration, testing, etc. of the SATA HDD integrity verification system developed.