• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 1999년도 춘계공동학술대회: 지식경영과 지식공학
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• pp.347-350
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• 1999

자율무인잠수정은 자율운항을 위해서 자동화된 제어시스템이 필요하다. 제어시스템은 기능적 측면에서 임무계획단계(mission planning level), 임무제어단계(mission control level), 선체제어단계(vehicle control level)로 구분한다. 자율무인잠수정의 효과적인 임무 수행을 위해서는 임무제어단계의 운행 경로 설정과 제어가 중요하다. 자율무인잠수정은 잠수정의 주변환경을 추상화한 후 탐색기법을 이용하여 경로를 설정한다. 이때 검색기법의 효율적 적용을 위해서는 효과적으로 추상화된 탐색모형이 필요하다. 대표적인 탐색모형으로는 3차원 격자절대좌표 모형(3-dimensional grid unit coordinate model)(1)을 들 수 있다. 그러나 이 모형은 불필요한 동작의 반복, 이동 격자에 따른 비일관성과 같은 취약점이 존재한다. 본 연구에서는 이 모형의 취약점을 개선하기 위해서 자율무인잠수정의 위치 기반 상대적 격자좌표 모형(relative grid unit coordinate model based on AUV state)을 제안한다.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 1999년도 춘계공동학술대회-지식경영과 지식공학
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• pp.347-350
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• 1999

자율무인잠수정은 자율운항을 위해서 자동화된 제어시스템이 필요하다. 제어시스템은 기능적 측면에서 임무계획단계(mission planning level), 임무제어단계(mission control level), 선체제어단계(vehicle control level)로 구분한다. 자율무인잠수정의 효과적인 임무 수행을 위해서는 임무제어단계의 운행 경로 설정과 제어가 중요하다. 자율무인잠수정은 잠수정의 주변환경을 추상화한 후 탐색기법을 이용하여 경로를 설정한다. 이때 검색기법의 효율적 적용을 위해서는 효과적으로 추상화된 탐색모형이 필요하다. 대표적인 탐색모형으로는 3차원 격자절대좌표 모형(3-dimensional grid unit coordinate model)[1]을 들 수 있다. 그러나 이 모형은 불필요한 동작의 반복, 이동 격자에 따른 비일관성과 같은 취약점이 존재한다. 본 연구에서는 이 모형의 취약점을 개선하기 위해서 자유무인잠수정의 위치 기반 상대적 격자좌표 모형(relative grid unit coordinate model based on AUV state)을 제안한다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.349-354
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• 1998

The grid reference system (GRS) has been useful for identifying the geographical location of satellite images. In this study we derive a GRS for the KOMPSAT Electro-Optical Camera (EOC) images. The derivation substantially follows the way that SPOT defines for its GRS, but incorporates the KOMPSAT orbital characteristics. The KOMPSAT EOC GRS (KEGRS) is designed to be a (K,J) coordinate system. The K coordinate parallel to the KOMPSAT ground track denotes the relative longitudinal position and the J coordinate represents the relative latitudinal position. The numbering of K begins with the prime meridian of K=1 with K increasing eastward, and the numbering of J uses a fixed value of J=500 at all center points on the equator with J increasing northward. The lateral and vertical intervals of grids are determined to be 12.5 km about at the 38$^{\circ}$ latitude to allow some margins for the value-added processing. The above design factors are being implemented in a satellite programming module of the KOMPSAT Receiving and Processing System (KRPS) to facilitate the EOC data collection planning over the Korean peninsula.

• 대한기계학회논문집A
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• 제29권2호
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• pp.247-252
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• 2005

This research presents a three-dimensional modeling technique for a flexible sheet. A relative coordinate formulation is used to represent the kinematics of the sheet. The three-dimensional flexible sheet is modeled by multi-rigid bodies interconnected by out-of-plane joints and plate force elements. A parent node is designated as a master body and is connected to the ground by a floating joint to cover the rigid motion of the flexible sheet in space. Since the in-plane deformation of a sheet such as a paper and a film is relatively small, compared to out-of-plane deformation, only the out-of-plane deformation is accounted for in this research. The recursive formulation has been adopted to solve the equations of motion efficiently. An example is presented to show the validity of the proposed method.

• Journal of Mechanical Science and Technology
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• 제15권8호
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• pp.1090-1096
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• 2001

In this paper, new methods for efficiently solving linear acceleration equations of multibody dynamic simulation exploiting sparsity for real-time simulation are presented. The coefficient matrix of the equations tends to have a large number of zero entries according to the relative joint coordinate numbering. By adequate joint coordinate numbering, the matrix has minimum off-diagonal terms and a block pattern of non-zero entries and can be solved efficiently. The proposed methods, using sparse Cholesky method and recursive block mass matrix method, take advantages of both the special structure and the sparsity of the coefficient matrix to reduce computation time. The first method solves the η$\times$η sparse coefficient matrix for the accelerations, where η denotes the number of relative coordinates. In the second method, for vehicle dynamic simulation, simple manipulations bring the original problem of dimension η$\times$η to an equivalent problem of dimension 6$\times$6 to be solved for the accelerations of a vehicle chassis. For vehicle dynamic simulation, the proposed solution methods are proved to be more efficient than the classical approaches using reduced Lagrangian multiplier method. With the methods computation time for real-time vehicle dynamic simulation can be reduced up to 14 per cent compared to the classical approach.

• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.305-311
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• 2005

This research presents a three-dimensional modeling technique for a flexible sheet. A relative coordinate formulation is used to represent the kinematics of the sheet. The three-dimensional flexible sheet is modeled by multi-rigid bodies interconnected by out-of-plane joints and plate force elements. A parent node is designated as a master body and is connected to the ground by a floating joint to cover the rigid motion of the flexible sheet in space. Since the in-plane deformation of a sheet such as a paper and a film is relatively small, compared to out-of-plane deformation, only the out-of-plane deformation is accounted for in this research. The recursive formulation has been adopted to solve the equations of motion efficiently. An example is presented to show the validity of the proposed method.

• 대한기계학회논문집
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• 제17권6호
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• pp.1509-1517
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• 1993

본 연구에서는 3차원 운동을 하는 다물체 기구가 물체 수와 조인트 연결상태 만 주어진 상태에서 구성상태에 따라 절점 좌표계를 이용하여 모델링하고 MACSYMA를 써서 복잡단조로운 대수 계산을 하여 모든 운동학적 정보를 얻어내며 수치계산이 필요 하면 별도의 프로그램을 이용 수치해석을 하는 과정을 밟는다.

• 한국정보통신학회논문지
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• 제15권1호
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• pp.89-98
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• 2011

본 논문에서는 휴대폰이나 TV 등의 터치화면에 한 번의 터치와 터치된 상태에서의 드래그(drag) 및 방향전환 동작만으로 문자를 용이하게 입력할 수 있고, 다층 구조 메뉴를 신속하고 편리하게 검색 및 선택할 수 있는 새로운 터치 유저 인터페이스 방식을 제안한다. 또한, 터치면의 고정된 위치에 고정된 문자를 할당함으로서 한정된 크기의 터치 면에 여러 문자를 중복할당 할 수 밖에 없는 기존의 절대좌표 방식의 한계성을 극복하기 위하여 터치 위치 이동에 따라 상대좌표를 도출하고 상대좌표에 대응되는 문자를 표시함으로서 한정된 터치영역에서 더 많은 문자를 수용할 수 있는 상대좌표 기반의 문자 할당 및 입력방식을 제안한다. 제안된 방식은 IPTV 플랫폼의 리모컨과 셋톱박스로 구현되어 제안 방식의 실용성과 유효성을 입증한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.573-576
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• 2005

This research presents a three-dimensional modeling technique for a flexible sheet. A relative coordinate formulation is used to represent the kinematics of the sheet. The three-dimensional flexible sheet is modeled by multi-rigid bodies interconnected by out-of-plane joints and plate force elements. A parent node is designated as a master body and is connected to the ground by a floating joint to cover the rigid motion of the flexible sheet in space. Since the in-plane deformation of a sheet such as a paper and a film is relatively small, compared to out-of-plane deformation, only the out-of-plane deformation is accounted for in this research. The recursive formulation has been adopted to solve the equations of motion efficiently. An example is presented to show the validity of the proposed method.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권3호
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• pp.235-249
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• 2018

The Artificial Neural Network (ANN) model has been known as one of the most effective theories for automatic ship berthing, as it has learning ability and mimics the actions of the human brain when performing the stages of ship berthing. However, existing ANN controllers can only bring a ship into a berth in a certain port, where the inputs of the ANN are the same as those of the teaching data. This means that those ANN controllers must be retrained when the ship arrives to a new port, which is time-consuming and costly. In this research, by using the head-up coordinate system, which includes the relative bearing and distance from the ship to the berth, a novel ANN controller is proposed to automatically control the ship into the berth in different ports without retraining the ANN structure. Numerical simulations were performed to verify the effectiveness of the proposed controller. First, teaching data were created in the original port to train the neural network; then, the controller was tested for automatic berthing in other ports, where the initial conditions of the inputs in the head-up coordinate system were similar to those of the teaching data in the original port. The results showed that the proposed controller has good performance for ship berthing in ports.