• 대한공간정보학회지
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• 제12권4호
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• pp.35-43
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• 2004

다중빔 음향탐사 시스템(Multibeam Echosounder system : MBES)은 넓은 지역을 소해측량(swath)하여 전자해도 제작, 고정밀 DEM 획득, 동영상 제작 등에 활용하는 최신 수로측량기술이다. MBES의 정확도향상 연구를 위한 기초연구로서 DGPS와 움직임측정센서(Motion senser)의 측정값을 비교 분석하여 선박의 동적 거동특성을 연구하였다. DGPS를 선체 전후, 좌우에 설치하여 측량한 GPS 위치 값의 수신정확도는 Roll은 ${\pm}0.0016^{\circ}$, Pitch는 ${\pm}0.0009^{\circ}$로 움직임측정센서 값의 정확도 평가가 가능한 양호한 정도를 얻었다. DGPS와 움직임측정센서의 Heading, Pitch, Roll 상관관계는 모두 정상관 관계를 나타냈다. 또한, 각 변화량에 따른 편차량의 상관관계는 정상관 관계이나 탐사선의 급회전, 진동 등과 같은 요소에 의해 편차가 발생 될 것으로 사료된다. GPS에 의한 조위변화량, Heave값은 움직임측정센서 값과 유사하며, GPS속도는 설치장소에 따라 변화가 있어 영향이 가장 적은 선박의 중심선에 설치하는 것이 적당하다. MBES Processor 장치에 입력되는 자이로, 움직임측정센서 값이 DGPS 실시간 관측 값보다 자이로는 15초, Pitch, Roll, Heave는 13초 시간차가 있어 MBES 최종값의 정확도에 영향을 줄 수 있는 것으로 사료된다.

• 한국지능시스템학회논문지
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• 제24권5호
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• pp.462-469
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• 2014

본 논문은 공감각의 공학적인 응용 및 표현방법에 관한 기초연구로서, 인간이 인지할 수 있는 감각들 중 근감각을 시각 및 청각 요소로 변환하는 기본 시스템의 구축을 목표로 한다. 구축방법으로서, 근감각 신호를 3축 가속도 센서 및 2축 자이로센서로부터 계산된 롤(roll), 피치(pitch) 신호를 통하여 근감각 신호 데이터를 획득하고 그 데이터에서 시각적 컬러 정보와 청각적 정보로 변환하는 방법을 제안한다. 롤 신호는 HSI 컬러 모델의 명도(Intensity)와 청각의 요소인 옥타브(Octave)로 변환하고, 피치 신호는 HSI 컬러 모델의 색상(Hue)과 청각의 음계(Scale)에 대응하여 변환한다. 추출된 HSI 컬러모델의 요소성분들을 기반으로 RGB 컬러모델로 변환한 후 실시간 컬러 출력신호를 얻는다. 또한, 청각의 요소인 옥타브 및 음계 성분을 기반으로 MIDI 신호로 변환, 합성한 후 실시간 사운드 출력신호를 얻는다. 실험에서, 신체의 움직임 즉 근감각을 표현하는 롤과 피치 값에서 색과 음 사이의 유사성에 기초한 변환관계에 따라 정상적인 색과 음이 출력되는 것을 확인하였다.

• 한국해양공학회지
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• 제31권3호
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• pp.196-201
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• 2017

A cylindrical structure has a very long period of heave and pitch motion response in ocean waves. To obtain the dynamic stability of a cylindrical structure, it is necessary to obtain the suitable metacentric height (GM). However, in a structure with sufficient metacentric height, Mathieu instability can occur if the natural frequency of the heave motion is double the natural frequency of the roll and pitch motion. This study carried out numerical calculations and experiments for vertical-axis wind turbines with cylindrical floaters, which had three different centers of gravity. In the regular wave experiment, the divergence of the structure motion without yaw was observed when the natural frequency of the heave motion was double the natural frequency of the roll and pitch motion. In the irregular wave experiment, the motion spectra of the structures with the different centers of gravity were compared, and one was very high when the natural frequency of the heave motion was double the natural frequency of the roll and pitch motion.

• 한국기계가공학회지
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• 제12권5호
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• pp.16-22
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• 2013

A two-dimensional photonic crystal structure was investigated using a roll-to-roll nanoreplication and physical vapor deposition processes for the inexpensive enhanced fluorescence substrate which is not sensitive to the polarization directions of excitation light source. An 8 inch silicon master having nano dot array with a diameter of 200 nm, a height of 100 nm and a pitch of 400 nm was prepared by KrF laser scanning lithography and reactive ion etching processes. A flexible polymer mold was fabricated by flat type UV replication process and a deposition of 10 nm nickel layer as an anti-adhesion layer. A roll mold was prepared by warping the flexible polymer mold on an aluminum roll base and a roll-to-roll UV replication process was carried out using the roll mold. After the deposition of ~ 100 nm $TiO_2$ layer on the replicated nano dot array, a 2 dimensional photonic crystal structure was realized with a resonance wavelength of 635 nm for both p- and s-polarized light sources.

• 한국해양공학회지
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• 제38권1호
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• pp.1-9
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• 2024

The vertical center of gravity (VCG) has a significant impact on the roll motion response of a surface ship, particularly oil tankers based on the oil level in the tanker after discharging oil at several stations or positional changes, such as changes in the superstructure and deck structure. This study examined the motion response of the Korea very large crude carrier 2 (KVLCC2) at various VCGs, especially roll motion when the VCG changed. The potential theory in the Ansys AQWA program was used as a numerical simulation method to calculate the motion response. On the other hand, the calculations obtained through potential theory overestimated the roll amplitudes during resonance and lacked precision. Therefore, roll damping is a necessary parameter that accounts for the viscosity effect by performing an experimental roll decay. The roll decay test estimated the roll damping coefficients for various VCGs using Froude's method. The motion response of the ship in regular waves was evaluated for various VCGs using the estimated roll-damping coefficients. In addition, the reliability of the numerical simulation in motion response was verified with those of the experiment method reported elsewhere. The simulation results showed that the responses of the surge, sway, heave, pitch, and yaw motion were not affected by changing the VCG, but the natural frequency and magnitude of the peak value of the roll motion response varied with the VCG.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.139-142
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• 2006

Numerous simulation studies and researches have recently revealed the rapid development and evolution in the emerging area of intelligent unmanned aerial vehicle (UAV). This study aims to develop a flight performance evaluation about the wireless unmanned helicopter. The process includes the design and testing of flight hardware and software that interprets sensor data. For the unmanned helicopter used in this research, an inertial sensor that provides posture (roll, pitch and yaw angles) and a Bluetooth is used to provide wireless connection between the user's pc and the helicopter were installed in the helicopter the helicopter's pitch, roll and yaw were the communication data. The accuracy of the system was confirmed by a computer simulation. The software also has been developed to support operators and displays helicopter position and posture by graphics.

• Journal of Advanced Marine Engineering and Technology
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• 제32권7호
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• pp.1068-1079
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• 2008

Tilt and heading angles information of a remotely operated vehicle (ROV) are very important in underwater navigation. This paper presents a low.cost tilt and heading estimation system. Three single.axis rate gyros, a tri-axis accelerometer, and a tri-axis magnetometer are used. Output signals coming from these sensors are fused by two Kalman filters. The first Kalman filter is used to estimate roll and pitch angles and the other is for heading angle estimation. By using this method, we have obtained tilt (roll and pitch angles) and heading information which are reliable over long period of time. Results from experiments have shown the performance of the presented system.

• 한국군사과학기술학회지
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• 제11권3호
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• pp.129-137
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• 2008

Hull-Mounted Sonar(HMS) has been the main equipment to detect and track underwater threats like torpedoes and enemy submarines. The HMS has short warming-up time and is employable independently with sea-state and weather condition. But these bad environmental condition and ship maneuvering make ship's roll and pitch. Ship's roll and pitch make unstability of sensor position, then cause degradation of the HMS performance. In this paper, we will show how the unstability influences the HMS performance, propose the 'Beam Stabilization Beamforming Technique' to overcome these phenomenon. And present the effectiveness of proposed technique by comparing with conventional beamforming result.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1482-1487
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• 2003

This paper presents a new family of 4-DoF parallel mechanism with two platforms. The new mechanism is composed of front and rear platforms, and three limbs. Two limbs with 6dof joint (P-P-S-P) are attached to the each platform and are perpendicular to baseplate, while the middle limb with 4-Dof joints (R-R-R-P or R-R-P-P) is attached to the revolute joint that connect front and rear platform. The two-DoF-driving mechanism at the middle limb with two base-fixed prismatic actuators can generate the heaving and roll motions or two translational motions. Therefore, Therefore, the new 4-Dof parallel mechanism (1T-3R) can generate pitch motions at each platforms, roll, and heaving motions, while another type of new 4-Dof parallel mechanism (2T-2R) can generate pitch motions at each platforms, x and z translational motions. For 1T-3R mechanism, kinematic analyses including inverse, forward kinematics, and Jacobian are performed.

• 한국안전학회지
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• 제25권6호
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• pp.60-64
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• 2010

The purpose of this study if to prevent dangerous accident of the overthrow of the tower crane in summer's hurricane. We develop the SMS in order to give automatic alarm system to operator within the dangerous range and to give a information of the exactly slope in the real time. The slope value of the tower crane is compose of direction, pitch by the front and rear, roll by the right and left and synthesis by the its pitch and roll. Especially, the synthesis eliminate the effect of the wall tie or wire bracing. So, this value should correctly indicate the actual slope. In this study, more applying field test should be applied with the SMS. In the future, a more measurement device can be applied to, and be able to feed more alarm criteria for the review of the risk in the field.