• 한국항해항만학회지
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• 제47권2호
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• pp.85-92
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• 2023

The hardware of an LED lighting control system for coastal lighting at coastal pier entrance consists of a power supply unit, an AVR control unit, a CLCD output unit, an LED control unit, a scenario selection switch unit, and an operation speed display unit. It is made of an 8-channel. The CPU used ATmega128 and the FET was used to control the current signal. To operate the CPU, DC 12V was converted to DC 5V using a regulator 7805. A heat sink was used to remove heat generated in the FET. By connecting the load LED module to the manufactured 8-channel LED lighting control system, the operation was confirmed through various production scenarios. In addition, a control system was designed to show the most suitable color for the atmosphere of the coastal pier according to the input value of temperature and illumination using a fuzzy control system. Computer simulation was then conducted. Results confirmed that fuzzy control did not need to store many data inputs due to characteristics of artificial intelligence and that it could efficiently represent many output values with simple fuzzy rules.

• 한국수산과학회지
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• 제28권5호
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• pp.624-634
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• 1995

가막만의 해수유동 변동특성을 연구하기 위하여 1994년 7월 21일부터 8월 8일까지 가막만 남쪽 입구의 송도 부근, 북쪽 입구의 여수, 그리고 만 중앙부의 평사 부근의 3개 지점에 유속계를 계류하였고, 송도 선착장과 여수항 부근의 2개 지점에 조위계를 설치하여 10분 간격으로 연속관측하였다. 가막만의 양쪽 수로에 도달하는 조석파의 위상관계를 알아보기 위하여 기기를 남쪽과 북쪽의 입구에 설치하였으며 이들 입구를 통해서 유입, 유출되는 조류가 만 내부의 해수순환에 어떤 영향을 주는지 알아보기 위해서 내만의 평사 부근에 유속계를 추가로 설치하였다. 최대조차는 여수와 송도에서 각각 357, 352cm 였다. M2, S2, Kl, O1 분조의 진폭은 여수에서는 각각 95.5, 48.8, 20.5, 14.0cm 였고 송도에서는 각각 93.6, 47.2, 21.3, 13.1cm 로서 조석의 형태수는 공통적으로 0.25 미만으로 반일주조가 지배적이었다. 양쪽 입구를 통해서 들어오는 주요분조의 위상차는 거의 없었다. 천해조 성분은 양쪽 모두 전체 진폭의 $4\%$ 이하로서 마찰효과 및 비선형효과는 매우 작았다. 조류의 최대유속은 송도부근에서 약 100m/sec, 내만의 평사에서 약 40cm/sec 였으며 M2분조의 유속은 각각 47.2, 14.8cm/sec 였다. 송도부근에서 조류성분은 주로 북서-남동 방향이고 반시계 방향의 회전성을 가지고 있으며 항류 성분은 남서 방향으로 17cm/sec 였다. 반면에 내만에서는 북동-남서 방향의 조류성분이 지배적이고 시계방향으로 회전하며 항류는 남동방향이고 0.9cm/sec 로 매우 약하지만 시간적으로 바람의 영향을 많이 받는 것으로 나타났다 전반적으로 가막만의 동부 내만과 송도 부근에서는 남쪽방향으로의 항류성분이 존재하는데 그 원인을 설명하기 위해서는 보다 충분한 관측을 통한 해수순환에 관한 연구가 필요하다.

• 수산해양기술연구
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• 제55권1호
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• pp.7-19
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• 2019

This study was conducted in order to improve opening efficiency of the miniaturized small-scale net for anchovy boat seine gear to reduce the fleet size. Field experiment was performed to observe geometry of nets by catcher boats. When the distance between the two ships was 150, 300 and 450 m and the speed of towing nets was 0.6, 0.9, and 1.2 kt, the vertical opening and actual opening of each part of the miniaturized small-scale net was as follows: the front part of the wing net, 6.8-9.5 m, 45-63%; the middle part of the wing net, 16.1-30.7 m, 34-65%; the entrance of the inside wing net, 21.6-41.2 m, 44-84%; the square and bosom, 17.4-34.0 m, 38-75%; the entrance of the body net, 16.5-29.4 m, 36-64%; the entrance of the bag net, 14.5-21.9 m, 70-106%; the flapper, 6.7-7.7 m, 81-83%, and the end of the bag net, 8.6-10.9 m, 64-81%. The tension of towing nets was measured to be 2,734-6,812 kg approximately, which indicates that the fleet can tow nets with 350 hp, the standard engine horse power. The fishing operation time was shortened comparing to existent net with the large-scale buoy attachment operation. It was also possible to operate the ship without fish detecting boat.

• 대한토목학회논문집
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• 제29권2D호
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• pp.167-173
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• 2009

일반적으로 사용되는 고속도로 합류부 영향권은 합류지점을 중심으로 상류 100m, 하류 400m를 포함하는 총 500m로 정의된다. 그러나 실제 합류부의 교통류특성은 하류부보다는 상류부에 합류영향이 크게 미치는 것으로 관찰된다. 따라서 본 연구에서는 고속도로 우측합류부 및 좌측합류부를 대상으로 차량간 상충으로 정의되는 난류현상을 이용하여 고속도로 합류부의 영향권을 분석하였다. 약 500m 간격으로 설치되어있는 현재의 교통류검지체계의 한계를 극복하기 위하여 동일한 도로조건의 합류부지점에 설치되어있는 교통류검지기를 통하여 수집된 원시데이터를 이용하였다. 각 지점별 데이터를 유사한 교통 조건으로 구분하기 위하여 도로의 서비스수준을 기준으로 총 72시간의 데이터를 분류하였다. 교통류 난류현상의 분석기준을 속도의 표준편차로 규정하고 분석한 결과, 우측합류부와 좌측합류부 모두 합류부의 직접 영향을 받는 구간으로 상류부 300m에서 하류부 400m까지 약 700m 구간이 도출되었으며 이는 기존의 영향권보다 상류부로 200m확장된 영역을 포함하는 결과이다.

• 대한조선학회논문집
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• 제35권2호
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• pp.1-7
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• 1998

중형 고속어업지도선의 선형개발에 관한 연구를 조선대학교 회류수조에서 수행하였다. 현재 운항중인 같은 크기의 15노트 급 선형을 모선(CU-015)으로 하여 모선의 선도를 20노트 항주에 적합하도록 길이를 연장하고 선형을 변경하였으며, 고속화에 따른 선수 쇄파를 최소화 할 수 있는 선수선형 개발 및 고마력 기관에 적합한 충분한 용적을 유지하며 저항추진 성능을 향상시킬 수 있는 U-형 선미형상의 개발을 주로 수행하였다. 모선의 선형수정에 많은 제약이 있었으나 결과적으로 도출된 개발선형은 상당한 조파저항 감소의 효과가 있었다.

• 대한기계학회논문집B
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• 제21권8호
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• pp.963-972
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• 1997

As a high-speed train enters a tunnel, a compression wave is generated ahead of it due to the piston action of train. The compression waves propagate along the tunnel and reflect at the exit of tunnel. A complex wave phenomenon appears in the tunnel, because of the successive reflections of the pressure waves at the exit and entrance of tunnel. The pressure waves give rise to large pressure transients which impose the fluctuating loads on the running train. It is highly needed that the pressure transients should be predicted to design the train body and to improve the comfortableness of the passengers in the train. In the present study, the pressure transients were calculated numerically for a wide range of train speed and compared with the previous tunnel tests. The calculation results agreed with ones of the tunnel tests, and the mechanism of pressure transients was made clear.

• 대한기계학회논문집B
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• 제21권8호
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• pp.983-995
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• 1997

As a high-speed train enters a tunnel, a compression wave is generated ahead of it due to the piston action of train. The compression waves propagate along the tunnel and reflect backward at the exit of tunnel. A complex wave phenomenon appears in the tunnel, because of the successive reflections of the pressure waves at the exit and entrance of tunnel. The pressure waves can give rise to large pressure transients which impose the fluctuating loads on the running train. It is highly needed that the pressure transients should be predicted to design the train body and to improve the comfort for the passengers in the train. In the present study, the pressure transients and aerodynamic drag for two-trains running in a tunnel were calculated numerically for a wide range of train speed, and compared with the results of the previous tunnel tests and calculations for one train. The present calculation results agreed with ones of the tunnel tests, and the mechanism of pressure transients was made clear.

• 한국항만학회지
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• 제13권2호
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• pp.333-350
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• 1999

Today freeway is thought to be a very important transportation facility carrying tremendous traffic flow as the main corridor within the area of between the areas. However freeway is experiencing severe congestion and accidents by increased entrance ramp flow especially at peak time period. Ramp meters on the freeway entrance ramps that supply traffic to the freeway in a measured or appropriately regulated amount are needed for alleviating freeway congestion. Because ramp meters can be operated to discharge traffic at a measured or regulated rate thus maintaining more uniform speed on the mainline section maximizing the throughput to the freeway within the capacity of a downstream bottleneck and reducing the congestion related accidents. Thus the objectives in this study were to analyze the traffic characteristics on the freeway I-94 with ramp metering system before/after ITS technology in Detroit (Michigan) area compare shifts of the traffic characteristics on the freeway I-94 before/after ITS technology and finally suggest a better ramp metering strategy for the freeway system The following results were obtained: i)Flow occupancies and speeds on the mainline merge section of freeway were shown to be a big difference depending on the peak periods areas and directions based on the distribution of traffic flow characteristics on the freeway. ii)Reduced speed was shown to be more than 5 mph and ramp flow was also shown to be more than 240 vph at peak periods if there was the ramp metering system constructed on the freeway. iii)Ramp metering system was shown to be optimally operated on the freeway if ramp flow could be maximized within the range of over 900 vph and reduced occupancy could be also maximized by no more than 2 percent at peak periods. iv)The average flows on the freeway after the ITS technology were shown to be a decrease of over 20% depending on the peak periods areas and directions when compared with those flow on the freeway before the ITS technology. over 20% depending on the peak periods areas and directions when compared with those speeds on the freeway before the ITS technology. vi)The average metering rates on the freeway after the ITS technology were shown to be an increase of over 10% depending on the peak periods areas and directions when compared with those metering rates on the freeway before the ITS technology.

• 한국도로학회논문집
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• 제13권4호
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• pp.151-158
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• 2011

고속도로의 터널구간은 일반구간과는 다른 주행특성(속도, 교통량, 밀도 등)을 가지게 되고 이에 따라 고속도로 일반부에서 터널진입 전과 후에 운전자 행태가 변하는데, 가장 대표적인 예가 속도의 감소 현상이라 할 수 있다. 하지만, 이러한 다양한 요인들 중 현재까지 연구의 진행 추세는 도로의 용량, 속도감소 측면의 정량적인 부분에 초점을 맞춘 연구들 위주로 진행되고 있는 것이 현실이다. 따라서 본 연구에서는 터널의 다양한 여건을 고려할 수 있는 구간을 대상으로 설문조사와 설문결과 분석을 통해서 터널구간 속도감소에 영향을 미치는 정성적 요인들을 알아 보았다. 분석 결과 최근 증가 추세인 장대터널과 관련된 터널 자체의 형상(차로폭, 갓길폭, 터널길이)에 대한 요인이 터널 내부 속도감소에 영향을 미치는 것으로 나타났다. 또한 터널입구 보임여부와 같은 시각적 환경이 속도감소의 영향요인으로 나타났으며 터널 내부의 조명밝기에 따라 속도변화가 나타나는 것을 알 수 있었다. 본 연구결과를 활용하여 고속도로 터널부 설계관련 기술개발 및 서비스개선을 위해 지속적인 투자가 이루어질 것이라 판단된다.

• 한국안전학회지
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• 제32권2호
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• pp.132-146
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• 2017

Appropriate speed limits at a reasonable level in urban roads are highly important factors for efficient and safe movement. Thus, it is greatly necessary to develop the objective models or methodology based on engineering study considering factors such as traffic accident rates, roadside development levels, and roadway geometry characteristics etc. The purpose of this study is to develop the estimate model of appropriate speed limits at each road sections in urban roads using traffic information big data and field specific data and to review the effects of accident decrease. In this study, the estimate method of appropriate speed limits in directional two or more lanes of urban roads is reflecting features of actual variables in a form of adjustment factor on the basis of the maximum statutory speed limits. As a result of investigating and testing influential variables, the main variables to affect the operating speed are the function of road, the existence of median, the width of lane, the number of traffic entrance/exit path and the number of traffic signal or nonsignal at intersection and crosswalk. As a result of testing this model, when the differences are bigger between the real operating speed and the recommended speed limits using model developed in this study, the accident rate generally turns out to be higher. In case of using the model proposed in this study, it means accident rate can be lower. When the result of this study is applied, the speed limits of directional two or more lane roads in Seoul appears about 11km/h lower than the current speed limits. The decrease of average operating speed caused by the decrease of speed limits is 2.8km/h, and the decrease effect of whole accidents according to the decrease of speed is 18% at research road. In case that accident severity is considered, the accident decrease effects are expected to 17~24% in fatalities, 11~17% in seriously injured road user, 6~9% in slightly injured road user, 5~6% in property damage only accidents.