• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1998.04a
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• pp.101-110
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• 1998

The safe passing maneuver of a large vessel along the designed course through a narrow channel in the flow of strong current is greatly related with her maneuvering characteristics. This paper treats maneuvering characteristic of a large vessel changing her course with the use of her control surface in a narrow channel with strong current. In this paper, the author proposed mathematical models of calculating maneuvering motions of the very large LNG tanker altering course using her control surface and calculated passing tracks of the vessel through the channel and compared the calculated results with those of maneuvering simulations by a desk-top simulator. In general the motions with the calculated values and the simulated motions are well coincided with each other.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.882-884
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• 2018

드론은 최근 기상관측, 영상촬영, 인명구조 등의 다양한 분야로 활용 가능성이 입증되고 있다. 이에 따라 다양한 산업 분야에서 드론 적용을 위한 연구가 활발하게 진행되고 있으며, 또한 민간용 시장으로 빠르게 확산되고 있다. 이러한 확산은 일반인들도 드론에 대한 이해와 활용 관점을 가지게 되었고, 실험용 드론 시스템 제작/개발로 이어지고 고 있다. 그러나 드론은 비행체의 물리적 특성상 정밀한 제어가 용이하지 않기 때문에 많은 연습이 필요하다. 또한 법적으로 드론을 비행시킬 수 있는 공간이 다양하지 못하다. 따라서 이 논문에서는 드론을 처음 접하거나 조종이 미숙한 사람들을 대상으로 드론의 비행 조종 연습을 할 수 있는 웹 기반의 교육용 소프트웨어를 개발하고 그 실용 가능성을 평가한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.322-324
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• 2019

하천과 호소수에서 상당 부분의 수자원을 얻는 국내 상황을 고려할 때 하천 수질사고는 심각한 상황을 초래할 수 있다. 이 논문에서는 이동할 수 있는 수질 측정 장치와 측정한 수질 정보를 웹 페이지를 통해 사용자에게 제공하는 시스템을 제안한다. 수질 측정 장치는 모형 배 형태이다. 관리자는 블루투스 통신으로 수질 측정 장치를 조종할 수 있다. 측정한 수질 정보를 와이파이 모듈을 통해 외부 서버의 데이터베이스에 저장한다. 사용자는 웹 페이지를 통해 실시간으로 측정되는 수질 정보를 확인할 수 있다. 구현 결과, 가벼운 무게와 조종 가능한 특성으로 이동성의 개선과 웹페이지를 통한 실시간 시각화를 확인하였다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.1
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• pp.57-62
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• 2009

In order to investigate the hydrodynamic interaction between the tug-barge and bank or ship which is crossing to the opposite direction, the towing simulations of tug-barge transportation were performed. Heading of barge, yaw moment and lateral force of tug boat were obtained by this simulation. The characteristics of results were analyzed and the safety towing method for tug-barge operation was proposed. In order to reduce the slewing motion of barge for safe towing operation, the speed of tug boat should be kept slow ahead state with shortened towing line as length of barge within the limits of the possible.

• Computational Structural Engineering
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• v.10 no.2
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• pp.161-169
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• 1997

It is known that tire plays an important role to the dynamic performances of a vehicle such as noise, vibration, ride and handling. Therefore, force and moment measurements have been a part of the traditional tire engineering process. In this paper, a computational analysis technique has been explored. A FE model is made to simulate inflation, vertical load due to the vehicle weight, and the slow rolling of a radial tire. A rigid surface with Coulomb friction is included in the model to simulate the slow rolling contact. The tire slip during the in-plane motion of the rigid surface is calculated. Results are presented for both lateral and vertical loads, as well as straight ahead free rolling. The calculated and measured tire slips are in good correlation. A Study on slow Rolling Tire for perdiction of tire Forces and Moments.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.2
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• pp.114-126
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• 2009

The authors adopt the Unmanned Undersea Vehicle(UUV), which has taken the shape of manta(Sohn et al. 2006). They call here it Manta-type Unmanned Undersea Test Vehicle(MUUTV). MUUTV is based on the same design concept as UUV called Manta Test Vehicle, which was originally built and operated by the Naval Undersea Warfare Center(Lisiewicz and French 2000, Sirmalis et al. 2001). In order to evaluate manoeuvring motion characteristics of MUUTV, numerical simulation technique has been utilized. Previous mathematical model on manoeuvring motion of MUUTV(Sohn et al. 2006) is basically adopted. Result of static experiment carried out in circulating water channel and a part of NSRDC standard model(Feldman 1979) on rotational mode are supplemented. Some of the hydrodynamic derivatives are obtained from model experiment in circulating water channel and the rest of them are estimated.

• Journal of the KSME
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• v.33 no.10
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• pp.856-860
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• 1993

차량의 조종안정성을 해석하기 위해서는 차륜과 현가장치에 의한 비선형성과 조향장치의 동특성 등을 고려한 3차원 차량 모델을 이용하여 정상상태와 과도상태에서의 조향입력에 대한 차량 주 행역학을 해석하여야 한다. 승차감, 조향성능, 주행안정성 등의 동적성능과 현가장치의 특성관 계를 규명하기위하여 3차원 차량모델에 의한 해석과 설계변수에의 민감도 해석을 수행할 필요가 있다.

• Journal of Navigation and Port Research
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• v.29 no.1 s.97
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• pp.9-15
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• 2005

To design ship channel is one of important factors for planning and developing a port. In most case, the core factors for designing ship channel are the layout and width of channel provided the net underkeel clearance is secured to be safe enough to pass. In this study, Variable Bumper Area(VBA) model is applied to design and assess ship channel. This model reflects ship's particular, ship domain theory, ship speed and mariner's ship handling skill and experience, especially external forces which cause leeway, set and drift and the change of ship maneuvering characteristics. A real time, full mission shiphandling simulator is used to analyze ship dynamic data according to mariner's ship control, external forces, ete. This model defines Domain degree and Domain-index for assessing the efficiency and safety of the channel. The proposed model is applied to Ulsan new port plan which has a channel width of 1.5 times the length of the largest vessel, a radius of 5 times the length of the largest vessel in a curve of 57 degree centerline angle and SBM facility adjacent to the lateral edge of channel. The result of this study shows that the width of the channel and radius of channel curve are suitable for the target ship but the difficulty of ship handling is caused by the large course change and SBM located in the vicinity of channel.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.25-32
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• 2006

An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modern version supersonic jet fighter aircraft. The flight control system utilize RSS criteria in both longitudinal and lateral-directional axes to achieve performance enhancements and improve stability. The T-50 advanced trainer employs the RSS concept in order to improve the aerodynamic performance and the flight control law in order to guarantee aircraft stability. The longitudinal two modes are the short period with high frequency and the phugoid mode with low frequency. The design goals of longitudinal control laws is concerned with the short period damping and frequency optimization using lower order equivalent system and utilizing the requirement of MIL-F-8785C. Analysis of short period mode has been and continues to be performed This paper addresses the analysis of aircraft phugoid node characteristics such as damping, natural frequency, and analysis of aircraft pitch motion that impacted by angle of attack limiter and auto pitch attitude control law.

• Journal of Aerospace System Engineering
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• v.16 no.3
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• pp.1-9
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• 2022

In this study, for development of the MDO (Multi Disciplinary Optimization) framework, the flight dynamic characteristic parameters of the ChangGong-91, a light aircraft, were extracted by an analytical method based on various semi-empirical methods, and the flight test method was compared and evaluated. The semi-empirical analysis methods for comparative subjects were the Perkins method, McCormick method, and Smetana method. The major stability/control derivatives and dynamic factors were calculated, using each method. As the comparison criteria, the flight test derivative estimates and dynamic factors were processed, using the output error method. Additionally, the flight characteristics of the light aircraft were analyzed and evaluated according to the provisions of the Korean Airworthiness Standard (KAS) of the Ministry of Land, Infrastructure and Transport, and MIL-F-8785C for the U.S. military.