• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2891-2894
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• 2011

Recently, the rise of the rail temperature is accelerating further due to the global warming, and the track stability(buckling) problem result from the axial force in the continuous welded rail(CWR) have become the most important issue. This track stability threatens the security of running trains in the hot summer. In order to prevent the track buckling in the hot summer and ensure the safety of the running train, as a part of the safety control plan for KORAIL high-speed railway, the train speed restriction according to the rail temperature was introduced in 2004. However, the conceptual and theoretical background of train-speed restriction is uncertain. In this paper, the theoretical study about the reasonable train-speed restriction is performed. For this purpose, the risk-based probabilistic stability evaluation of the track buckling is applied.

• BMB Reports
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• 제33권2호
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• pp.162-165
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• 2000

Polymerase chain reaction (PCR) is well established as an indispensable tool of molecular biology; and yet a limitation for cloning applications continues to be that products often require subsequent restriction to be that products often require subsequent restriction digests, blunt-end ligation, or the use of special linear vectors. Here a rapid, PCR-based system is described for the simple, restriction enzyme-free generation of synthetic, 'restriction-like' DNA fragments with staggered ends. Any 3'- or 5'-protruding terminus, but also non-palindromic overhangs with an unrestricted single strand length are specifically created. With longer overhangs, "Restriction-PCR" does not even require a ligation step prior to transformation. Thereby the technique presents a powerful tool e.g. for a successive, authentic reconstitution of sub-fragments of long genes with no need to manipulate the sequence or to introduce restriction sites. Since restriction enzyme-free and thereby devoid the limitations of partial DNA digests, "Restriction-PCR" allows a straight one-step generation and cloning of difficult DNA fragments that internally carry additional sites for specific sequence insertions or deletions can be precisely engineered into genes of interest. With these properties "Restriction-PCR" has the potential to add significant speed and versatility to a wide variety of DNA cloning applications.

• 한국자동차공학회논문집
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• 제9권2호
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• pp.130-136
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• 2001

This paper presents an of a brake pressure restriction valve to a motorcycle anti-lock brake system(ABS). In the conventional anti-lock brake system of automobiles, slip ratio as a control variable is actively controlled, which requires wheel speed sensors, ECU, and a pressure modulator. In the ABS valve that has been developed for use in motorcycles, however, the brake pressure that is close to the wheel locking pressure is preset by simple exercises and then the valve just allows to pass the wheel locking pressure and cutoff the remaining pressure. Simulation studies with a single wheel braking dynamics and lumped chassis model show that the pressure restriction valve has basic ABS functions as well as some robustness properties for the uncertain load and road conditions as well as various initial braking speeds. Field tests also show that the pressure restriction valve avoids the wheel locking effectively.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.830-835
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• 2004

In railway systems, the performance of turnout is one of the most important factors to improve the train's speed. Standard turnout, in which one track is split in main track side and turnout side. Because the main track side remains linear, speed restriction can be alleviated while train pass the main track side. The factors of speed restriction in main track side are strength of crossing and tongue rail, wheel back side pressure of guard rail and wing rail. In this study, we measured wheel back side pressure of guard rail to compare improved turnout with present turnout. In result, the wheel back side pressure of improved turnout was lower than present turnout, so its performance was proved.

• Structural Engineering and Mechanics
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• 제53권1호
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• pp.89-104
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• 2015

In current bridge management systems (BMSs), load and speed restrictions are applied on unhealthy bridges to keep the structure safe and serviceable for as long as possible. But the question is, whether applying these restrictions will always decrease the internal forces in critical components of the bridge and enhance the safety of the unhealthy bridges. To find the answer, this paper for the first time in literature, looks into the design aspects through studying the changes in demand by capacity ratios of the critical components of a bridge under the train loads. For this purpose, a structural model of a simply supported bridge, whose dynamic behaviour is similar to a group of real railway bridges, is developed. Demand by capacity ratios of the critical components of the bridge are calculated, to identify their sensitivity to increase of speed and magnitude of live load. The outcomes of this study are very significant as they show that, on the contrary to what is expected, by applying restriction on speed, the demand by capacity ratio of components may increase and make the bridge unsafe for carrying live load. Suggestions are made to solve the problem.

• 한국항공운항학회지
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• 제13권4호
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• pp.43-57
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• 2005

Traditionally aircraft had descended in steps to level at the MDA(Minimum Descent Altitude) during the conduct of non-precision approach. This "de-stabilized" method of flying an instrument approach procedure is considered as a major contributing factor in CFIT(Controlled Flight Into Terrain) accident and increasing pilot workload. In the effort to reduce CFIT accident and pilot workload, VNAV(Vertical Navigation) Approach has been suggested as means to manage the vertical component of non-precision approach procedure.[1] But In the actual circumstances in Korea, VNAV has not been using to reduce them because of many restriction facts and no published VNAV chart in particular airport. Therefore we are suggesting Constant Vertical Speed Approach Method, which is required few restriction facts, and the pilots who are using this method will experience a similar method like a Glideslope during proceeding non-precision approach. Consequently, We are expecting to reduce CFIT accidents and pilot workload.

• 한국ITS학회 논문지
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• 제14권6호
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• pp.91-99
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• 2015

본 연구는 서울, 수도권 및 부산광역시의 4지 신호교차로를 대상으로 도로의 기하구조측면, 교통특성, 환경특성 등 다양한 요인을 고려하여 교통사고예측모형을 구축하고 교차로사고와의 상호관계를 규명하고자 하였다. 분석 결과 기존의 음이항 모형보다 확률적 음이항 모형의 설명력이 높게 나타났으며 총 52개의 변수 중 10개의 변수가(주도로의 차로 수, 주도로의 좌회전 교통량, 주도로의 주행제약시설 수, 부도로의 우회전 교통량, 부도로의 교차로 시거, 교차로의 총 현시, 부도로의 중앙분리대 유무, 부도로의 제한속도, 부도로의 교통섬 유무, 부도로의 속도제약시설 수) 도시부 4지 신호교차로에서 교통사고에 영향을 미치는 유의한 변수로 나타났다. 또한 10개의 유의한 변수 중 2개의 변수가(부도로의 교차로 시거, 부도로의 차량 주행속도 제약 시설물 수)가 확률적 변수로 나타났다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.302-307
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• 2004

When trains run over a snow-covered track at high speed, the snow accereted under car bodies may drop during train running. The dropped snow/ice lumps scatter the ballast on the track damaging the car body and the environment along the track in snowy regions. In this study, the snow-fall condition in winter around the Seoul-Busan high-speed line has been investigated to yield the countermeasure for the high-speed line. The climate near Japanese and French high-speed line as well as the relationship between the climate and countermeasure has also been investigated and the direction of countermeasure for Seoul-Busan high-speed line has been deduced. Consequently, the amount and frequency of snow-fall near Seoul-Busan high-speed line is less than that of Japan and France, so the speed restriction could be the fundamental countermeasure for Seoul-Busan high-speed line, and additional measure on rolling stock and infrastructure should be followed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.476-478
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• 1997

A new speed detection method using low resolution incremental encoders, especially excellent in the low speed region and in the transient state, is proposed. The half period error of an incremental encoder is greater than the period error. So it's not recommended to quadruple the number of pulses per revolution, because it increase the ripple of speed. To overcome this restriction a speed detection, method has been proposed. But it requires so many latch circuits. Therefore we propose a new speed detection method that has different concept and has fewer latch circuits.

• 대한수의학회지
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• 제33권1호
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• pp.43-51
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• 1993

Mitochondrial DNA(mt DNA) of Mammalian is the circular one which the 16.5K base pairs and show the maternal inheritance. Evolutional speed of nucleotide sequence is very fast. So that polymorphic analysis of mt DNA provide the useful informations to investigate the genetic relations of interspecies. Authors trials were focussed to compare with the polymorphic differences of mitochondrial DNA between Jindo and Japanese mongrel dogs. DNA was extracted from bloods of 21 head of Jindo dogs and 20 head of Japanese dogs and isolated using 10 kinds of restriction endonucleases(Apa I, BamH I, Bgl II, EcoR I, EcoR V, Hinc II. Hind III, Pst I, Sty I, Xba I) and then separated by the agarose gel electrophoresis. After sourthern blotting hybridization was completed using the mtDNA of Japanese mongrel dogs as a probe. Autoradiography was used to compare the polymorphism of mtDNA both dogs. The results obtained were as follows; 1. mt DNA of Jindo dog showed polymorphism resulting cleavage with four kinds of restriction endonuclease, Apa I, EcoR V, Hinc II, Sty I. While in the Japanese mongrel dogs observed the polymorphism in the five kinds of restriction endonuclease supplemented with EcoR I. 2. Compared with both dogs the frequency differences of DNA polymorphism were recognized in the specific restriction endonuclease Apa I. Consequently in the restriction endonuclease Apa I both dogs classified with three types as A, B, C however in the Jindo dogs frequency of C type was 71.5 percent but in Japanese mongrel dogs observed 45 percent in the A type. 3. DNA polymorphism obtained from the use of five kinds of restriction endonuclease were classified with seven types. In Jindo dogs frequency was highest in the type 6 as 71.4 percent but in the Japanese mongrel dogs showed 35 percent in the type 5. 4. Genetic distances calculated by NEI method showed 0.0089 in Jindo dogs and was 0.0094 in the Japanese mongrel dogs.