• 한국정밀공학회지
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• 제33권3호
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• pp.207-216
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• 2016

A gerotor is suitable for miniature manufacturing because it has high discharge per 1 cycle and a simple structure, while also being widely used for lubrication oil of engines and as a hydraulic source of automatic transmission. In the automobile industry, improvements in fuel efficiency and noise reduction have recently come to the fore. It has also been necessary to continuously improve the flow rate and noise of internal gear pumps for better fuel efficiency through optimal gerotor and port shape design. In this study, to develop an optimal gerotor with a new lobe shape, 2-ellipses-combined, the equation of the lobe shape was derived, and CFD analysis results were compared for 2-ellipses with those of the previous gerotors (3-ellipses and ellipse1-involuteellipse2). A performance test for the oil pump with the optimal rotor (2-ellipses) was carried out and showed good agreement with the results obtained from CFD analysis.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2002년도 추계공동학술대회논문집
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• pp.127-132
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• 2002

This paper proposes a sensor-fusion technique where the data sets for the previous moments are properly transformed and fused into the current data sets to enable accurate measurement, such as, distance to an obstacle and location of the service robot itself. In the conventional fusion schemes, the measurement is dependent on the current data sets. As the results, more of sensors are required to measure a certain physical parameter or to improve the accuracy of the measurement. However, in this approach, instead of adding more sensors to the system the temporal sequence of the data sets are stored and utilized for the measurement improvement. Theoretical basis is illustrated by examples and the effectiveness is proved through the simulations. finally, the new space and time sensor fusion (STSF) scheme is applied to the control of a mobile robot in an unstructured environment as well as structured environment.

• 한국항해항만학회지
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• 제35권2호
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• pp.121-130
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• 2011

The localization of vehicle is an important part of an unmanned vehicle control problem. Pseudolite ultrasonic system(PUS) is the method to find an absolute position with a high accuracy by using ultrasonic sensor. And Gyro is the inertial sensor to measure yaw angle of vehicle. PUS can be able to estimate the position of mobile robot precisely, in which errors are not accumulated. And Gyro is a more faster measure method than PUS. In this paper, we suggest a more accuracy method of calculating PUS which is numerical analysis approach named Newtonian method. And also propose the fusion method to increase the accuracy of estimated angle on moving vehicle by using PUS and Gyro integrated system by Kalman filtering. To control the 4WS unmanned vehicle, the trajectory following algorithm is suggested. And the new concept arbitration of goal controller is suggested. This method considers the desirability function of vehicle state. Finally, the performances of Newtonian method and designed controller were verified from the experimental results with the 4WS vehicle scaled 1/10.

• 한국항만학회지
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• 제11권1호
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• pp.13-28
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• 1997

Today the congestion problem is a problem for the most of the cities to solve. Especially, traffic congestion in the big cities is occurring regardless of the rush-hours. Because the transportation facilities secured in the big cities are very low, and the financial resources and sites for the expansion of new transportation facilities are also limited. Therefore the appropriate Transportation system Management(TSM) techniques which could improve the transportation system are absolutely required to solve the transportation problems instead of the expansion of the transportation facilities in the big cities. The purpose in this study was to review the travel characteristics on the Pretimed Signalized - Intersections under the study in Pusan area, construct the travel systems during the different time-periods based upon the travel characteristics reviewed, and finally suggest the optimal travel systems which could reduce the traffic delay and fuel consumption of the Pretimed Signalized - Intersections based upon the travel system constructed. Based upon the results, it could be concluded that the pretimed signal system based upon the on-peak periods should not be applied to all the different time-periods on the Pretimed Signalized - Intersections(PSI) to reduce traffic delay and fuel consumption, and increase the travel capacity on the intersections in Pusan area.

• 대한지리학회지
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• 제28권3호
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• pp.247-267
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• 1993

제 2 차 세계대전 이후 등장한 컨테이너화에 의해 큰 발전을 가져온 현대항만의 수송기능을 이해하기 위하여, 본 연구는 교통결절점으로서의 부산항을 중심으로 컨테이너 수출화물을 통하여 배후지와 지향지의 공간구조를 파악하는 것을 목적으로 하였다. 분석결과, 수출 컨테이너 화물의 배후지는 대도시와 공업도시, 기타 지역으로 수출품목에 의해 유형화될 수 있으며, 주요 지향지는 각 선사의 수송항로에 있어 각 항만의 규모와 각 선사의 항만터미널 이용 편리도에 따라 결정되었다는 점을 밝혔다. 그리고 수출 컨테이너 화물의 배후지와 지향지의 결합에서 국적 3社 모두 품목에 따른 배후지의 유형은 유사하게 나타난다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2018년도 춘계학술대회
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• pp.228-229
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• 2018

선박의 대형화와 더불어 증가하는 컨테이너 물동량을 처리하기 위해 부산항은 글로벌 인프라를 조성, 신설 부두 추진, 항만의 개발 등 다양한 시각으로 노력하고 있다. 부산항이 향후 대형 선박 접안에 대비하여 인프라를 갖출 수 있다면 20,000TEU 이상 선박의 작업도 가능할 것이며, Megamax 시대의 중심 항만으로 성장할 수 있을 것이다. 하지만, 대형 선박 접안시 많은 선석과 장비, 작업시간이 필요하기 때문에 선박의 체선문제가 발생할 수 밖에 없다. 이에 따라, 본 연구에서는 시뮬레이션을 통해 대형선박 접안이 컨테이너 터미널 체선에 미치는 영향을 분석하고자 한다.

• 한국항해항만학회지
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• 제45권3호
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• pp.138-147
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• 2021

한진해운 파산 및 해운동맹의 재정립 등으로 부산항 컨테이너터미널의 운영 효율성 및 생산성 분석의 필요성이 증가하고 있다. 본 논문은 항만공사 공시자료 및 수집된 터미널 내부자료를 바탕으로 DEA 분석 및 Malmquist 생산성 지수 모형을 활용하여 부산신항 컨테이너 터미널 5개사의 효율성 및 생산성을 분석하였다. 분석결과 컨테이너터미널 5개사의 평균 효율성은 2018년 증가하였으나 2019년 소폭 하락한 것으로 나타났으며, Malmquist 지수를 통해 종합적인 생산성 변화를 살펴보면 A사를 제외한 모든 터미널이 생산성이 진보한 것으로 나타났다. 또한 설비 생산성의 경우 부산신항 남컨테이너터미널보다 북컨테이너터미널에 위치한 운영사들이 높은 것으로 나타났고, 자본 생산성의 경우 국적 선사인 HMM이 기항하는 D사가 가장 높은 것으로 나타났다. 노동 생산성의 경우 C사가 가장 높은 생산성을 보였으며, 선박작업 생산성의 경우 A사가 가장 높은 생산성을 보였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2003년도 춘계공동학술대회논문집
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• pp.115-120
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• 2003

기존연구에서는 예측 물동량을 선석당 안벽하역능력으로 나누어서 필요 선석 수를 산정하였으나 이는 선박의 규모에 따른 적ㆍ양하량과 선석점유율, 운영정보시스템의 발전에 따른 생산성 향상 등을 반영하지 못하여 실질적인 안벽능력을 산출하였다고 보기는 어렵다. 따라서 본 연구에서는 안벽능력은 터미널의 내부적 요건에 따라 변할 수 있다고 가정하고, 실제 터미널에 접안하는 선박의 규모별 적ㆍ양하량 및 선박 길이 등을 반영한 안벽길이 및 선석 수를 산정하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권2호
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• pp.287-312
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• 2011

Internet chat programs and instant messaging services are becoming increasingly popular among Internet users. One of the crucial issues with Internet chat is how to manage the corresponding pairs of questions and answers in a sequence of conversations. Although many novel methodologies have been introduced to cope with this problem, most are poor in managing interruptions, organizing turn-taking, and conveying comprehension. The Internet environment is recently evolving into a 3D environment, but the problems with managing chat dialogues with the standard 2D text-based chat have remained. Therefore, we propose a more realistic communication model for chat agents in 3D virtual space in this paper. First, we propose a new method to measure the capacity of communication between chat agents and a novel visualization method to depict the hierarchical structure of chat dialogues. In addition, we are concerned with communication networks for virtual people (avatars) living in virtual worlds. In this paper we consider a microscopic aspect of a social network in a relatively short period of time. Our experiments show that our model is highly effective in a virtual chat environment, and the communication network based on our model greatly facilitates investigation of a very large and complicated communication network.

• 수산해양기술연구
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• 제28권1호
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• pp.21-26
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• 1992

Generally a navigator evaluated the maneuverability of his ship by the scale of turning circle which was described only by the largest rudder angle of the port and starboard sides. But to have the sufficient knowledge of his ship's maneuvering characteristics he should consider the data about the new course keeping test, the spiral test, and the turning circle tests in accordance with the rudder angles together. In this paper the author performed the above tests to study the maneuverability of the stern trawler M.S. Pusan 404 which is a training ship of the National Fisheries University of Pusan. The obtained results are summarized as follows: 1. When the rudder angles being 5。, 10。, 20。, 30。, 35。 the advances of the starboard side turning circles were 12.8, 8.2, 4.8, 2.9, 2.7 times as large as the length of the ship, and of the port side turning circles were 13.3, 8.7, 5.4, 3.5, 2.9, time as large as the large as it. Under the same conditions the tactical diameters were 15.1, 9.7, 5.2, 3.1, 2.8 times as large as the length of the ship, for starboard side, and 17.2, 12.4, 6.4, 3.7, 3.2 times as large as it for port side. 2. As the rudder angle being increased the ratio of the advance to the tactical diameter was nearly 1 and her obeying ability was better than that of the small angle. 3. The mean values of the rates of speed reduction during the steady turning motion were 0.96, 0.92, 0.82, 0.71, 0.65 in accordance with the rudder angles. 4. The relative formulas between the distance to the new course y and the altering course x were as follows: When rudder angles being 10。, 20。, 30。, y=52.2222+1.6133x, y=48.750+0.9383x, y=39.250+0.655x respectively. 5. There was little difference of the distance to the new course between rudder angle 20。and 30。, and so it is desirable for a navigator to a navigator to use the small rudder angles unless sudden emergencies. 6. Though her rudder angle being small her course stability was good according to the spiral tests.