• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.73-78
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• 2013

In this paper, the vibration for a pickup actuator is described by mathematically analyzing its suspension configuration and motion, confined to lateral and torsional directions of suspensions. In order to prove the accuracy of this result, it is compared to a finite element analysis. Also it is shown that modal frequencies can be modified by changing design parameters in mathematical motion expressions.

• 한국정밀공학회지
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• 제13권8호
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• pp.13-27
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• 1996

소성가공이란 원재료를 소성변형(Plastic deformation)을 통해서 고체의 제품을 만드는 가공법이다. 가공중에 물체의 질량과 체적에는 크게 변화가 없다. 소성 가공중 주응력이 어떻게 작용하느냐에 따라서 소성가공을 여러가지로 분류하고 있다. 즉, Metal Forming은 다음과 같이 분류할 수 있다. 1) Compound Forming에는, Rolling, Free forming, Die forming, Stamping, Pressing 2) Tension compression forming에는, Drawing, Deep-drawing, Rimming, Spinning, Bulge forming 3) Tension forming에는 Lengthening, Widning, Deepening 4) Bending에는 Bending with linear tool motion, Bending with rotary tool motion 5) Thrust forming에는 Swaging, Twisting이 있다.

• 수산해양기술연구
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• 제45권4호
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• pp.267-275
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• 2009

According to the recent statistics of marine casualties in Korea, fishing boats are more likely to be ended in the casualties, and small fishing boats especially cause much more accidents in sinking and capsizing than any other big vessels. These casualties were mainly produced from the ignorance on the lack of own ship stability. From this view, this study aims to analyze the characteristics of stability on the crab trap fishing boat receiving transverse wave by means of carrying out the water tank test. The rolling angle of the model ship was affected largely with the displacement and the wave period of it, and the trends were shown that the magnitude of the angle was proportional to the displacement, but inversely to the wave period. And the wave height had effect on the rolling angle just in the specific range of the wave period. The force of steady wind didn't have influence on the rolling variation significantly.

• 한국운동역학회지
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• 제15권3호
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• pp.117-132
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• 2005

It was to study a following research of "A Kinematic Analysis of Air-rolling-breakfall in Judo". The purpose of this study was to analyze the Center of Gravity(COG) variables when performing Air-rolling-breakfall motion, while passing forward over(PFO) to the vertical-hurdles(2m height, take off board 1m height) in judo. Subjects were four males of Y. University squad, who were trainees of the demonstration exhibition team, representatives of national level judoists and were filmed by four 5-VHS 16mm video cameras(60field/sec.) through the three dimensional film analysis methods.COG variable were anterior-posterior directional COG and linear velocity of COG, vertical directional COG and linear velocity of COG. The data collections of this study were digitized by KWON3D program computed The data were standardized using cubic spline interpolation based by calculating the mean values and the standard deviation calculated for each variables. When performing the Air-rolling-breakfall, from the data analysis and discussions, the conclusions were as follows : 1. Anterior-posterior directional COG(APD-COG) when performing Air-rolling-breakfall motion, while PFO over to the vertical-hurdles(2m height) in judo. The range of APD-COG by forward was $0.31{\sim}0.41m$ in take-off position(event 1), $1.20{\sim}1.33m$ in the air-top position(event 2), $2.12{\sim}2.30m$ in the touch-down position(event 3), gradually and $2.14{\sim}2.32m$ in safety breakfall position(event 4), respectively. 2 The linear velocity of APD-COG was $1.03{\sim}2.14m/sec$. in take-off position(event 1), $1.97{\sim}2.22m/sec$. gradually in the air-top position(event 2), $1.05{\sim}1.32m/sec$. in the touch-down position (event 3), gradual decrease and $0.91{\sim}1.23m/sec$. in the safety breakfall position(event 4), respectively. 3. The vertical directional COG(VD-COG) when performing Air-rolling-breakfall motion, while PFO to the vertical-hurdles(2m height) in judo. The range of VD-COG toward upward from mat was $1.35{\sim}1.46m$ in take-off position(event 1), the highest $2.07{\sim}2.23m$ in the air-top position(event 2), and after rapid decrease $0.3{\sim}0.58m$ in the touch-down position(event 3), gradual decrease $0.22{\sim}0.50m$ in safety breakfall position(event 4), respectively. 4. The linear velocity of VlJ.COG was $1.60{\sim}1.87m/sec$. in take-off position(event 1), $0.03{\sim}0.08m/sec$. gradually in the air-top position(event 2), $-4.37{\sim}\;-4.76m/sec$. gradual decrease in the touch-down position(event 3), gradual decrease and -4.40${\sim}\;-4.77m/sec$. in safety breakfall position(event 4), respectively. When performing Air-rolling-breakfall showed parabolic movement from take-off position to air-top position, and after showed vertical fall movement from air-top position to safety breakfall. In conclusion, Ukemi(breakfall) is safety fall method Therefore, actions need for performing safety fall movement, that decrease and minimize shock and impact during Air-rolling-breakfall from take-off board action to air-top position must be maximize of angular momentum, and after must be minimize in touch-down position and safety breakfall position.

• IEIE Transactions on Smart Processing and Computing
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• 제1권2호
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• pp.78-87
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• 2012

In this paper, we address the tracking problem caused by camera motion and rolling shutter effects associated with CMOS sensors in consumer handheld cameras, such as mobile cameras, digital cameras, and digital camcorders. A modified particle filtering method is proposed for simultaneously tracking objects and compensating for the effects of camera motion. The proposed method uses an elastic registration algorithm (ER) that considers the global affine motion as well as the brightness and contrast between images, assuming that camera motion results in an affine transform of the image between two successive frames. By assuming that the camera motion is modeled globally by an affine transform, only the global affine model instead of the local model was considered. Only the brightness parameter was used in intensity variation. The contrast parameters used in the original ER algorithm were ignored because the change in illumination is small enough between temporally adjacent frames. The proposed particle filtering consists of the following four steps: (i) prediction step, (ii) compensating prediction state error based on camera motion estimation, (iii) update step and (iv) re-sampling step. A larger number of particles are needed when camera motion generates a prediction state error of an object at the prediction step. The proposed method robustly tracks the object of interest by compensating for the prediction state error using the affine motion model estimated from ER. Experimental results show that the proposed method outperforms the conventional particle filter, and can track moving objects robustly in consumer handheld imaging devices.

• 해양환경안전학회지
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• 제11권1호
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• pp.23-28
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• 2005

선박 횡동요는 물적 손실을 초래할 뿐만 아니라, 승선자의 거주성, 안전성 및 작업능률을 저하시키는 가장 큰 요인이 된다. 횡동요억제를 위한 많은 연구는 다양한 형태의 장치개발이라는 결과를 가져왔으며 상당한 효과를 얻고 있다. 지금까지 개발 된 대부분의 장치는 그 성능을 고려하지 야더라도 특수한 목적의 선박을 대상으로 설치$\cdot$운영되고 있으며, 고가이고 복잡하여 설치 상에도 많은 문제점을 안고 있다. 따라서 본 논문에서는 선박의 선미측에 설치한 플랩을 이용하여 운항중인 선박의 횡동요 억제에 관해 고찰하고 있다. 본 장치는 중$\cdot$소형의 선박에도 쉽게 설치하여 운용이 용이할 뿐만 아니라, 적절한 제어시스템 구축으로 피칭운동도 제어할 수 있는 장점이 있다. 본 논문에서는 이러한 장치를 설치한 선박에 대해 실험적 기법을 이용하여 모델링을 행하고 시뮬레이션을 통해 장치의 횡동요 억제효과를 검증하고 있다.

• Current Optics and Photonics
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• 제2권5호
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• pp.422-430
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• 2018

Rolling shutter operation of CMOS cameras can be utilized in optical camera communications in order to transmit data from an LED to mobile devices such as smart-phones. From temporally modulated light, a spatial flicker pattern is obtained in the captured image, and this is used for signal recovery. Due to the degradation of rolling shutter images caused by light smear, motion blur, and focus blur, the conventional decoding schemes for rolling shutter cameras based on the pattern width for 'OFF' and 'ON' cannot guarantee robust communications performance for practical uses. Aside from conventional techniques, such as polynomial fitting, histogram equalization can be used for blurry light mitigation, but it requires additional computation abilities resulting in burdens on mobile devices. This paper proposes a transition-based decoding scheme for rolling shutter cameras in order to offer simple and robust data decoding in the presence of image degradation. Based on the designed synchronization pulse and modulated data symbols according to the LED dimming level, the decoding process is conducted by observing the transition patterns of two sequential symbol pulses. For this, the extended symbol pulse caused by consecutive symbol pulses with the same level determines whether the second pulse should be included for the next bit decoding or not. The proposed method simply identifies the transition patterns of sequential symbol pulses other than the pattern width of 'OFF' and 'ON' for data decoding, and thus, it is simpler and more accurate. Experimental results ensured that the transition-based decoding scheme is robust even in the presence of blurry lights in the captured image at various dimming levels

• 한국의류학회지
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• 제32권10호
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• pp.1571-1583
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• 2008

The study aimed to investigate the actual condition of working clothes in the Changwon National Industrial Complex and to analyze the industrial workers' satisfaction with and preference to the working clothes in terms of the clothing performance and work motion factors. 1 major companies in machinery, automotive, industrial engineering, shipbuilding and rolling stock industries located in the industrial complex were selected as the subject firms. Approximately 900 workers responded to the questionnaire designed for the research and the results derived from the research were as follows. (1) The subject employees were divided into 4 work groups, i.e. the $1^{st}$ work group: managerial, general affairs, sales, production planning; the $2^{nd}$ group: quality assurance, material planning and distribution, product inspection; the $3^{rd}$ group: electric, facilities, machinery, vehicles; and the $4^{th}$ group: cutting, pressing, rolling, welding and coating. (2) The significant work environmental factors considered by all work groups were air ventilation, noise and dust factors and in particular, the most dissatisfied factors evaluated by manufacture workers were insulation, noise, dust and vibration. (3) According to the employees' work motion evaluation, the work motion diversity and frequency increased in proportion to the degree of work intensity. Besides, manufacture workers more frequently wore the working clothes even during the off-duty hours comparing to the evaluation of the other work groups. (4) The most important clothing performance factors considered by manufacture work groups were perspiration absorption, stretch, air permeability, tactile sense softness, soil proof in order.

• 한국항해항만학회지
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• 제29권10호
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• pp.839-845
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• 2005

조타에 의해 불규칙파 중 선박의 선수동요 및 횡요를 제어하는 횡요 감소시스템에 관한 연구를 수행하였다. 횡요를 포함한 선박 운동 시뮬레이션을 위해 4-자유도 조종 운동방정식을 사용하였고, 선체에 가해지는 외력으로서 파강제력이 고려되었다. 파강제력은 3차원 특이점 분포법에서 얻어진 주파수 전달함수로부터 시간영역해석법을 적용하였다. 선수동요와 횡요를 제어하는 PD 제어기를 각각 구성하고, 이를 선형 결합하여 횡요 감소 조타 제어기를 구성하였다. 조타 속도 및 타의 종류를 변화시켜 선수동요 및 횡요의 제어효율을 검토하였다.

• 대한교통학회지
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• 제32권5호
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• pp.503-512
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• 2014

본 논문에서는 펑크 타이어 힘 시험 연구 결과들을 다양하게 수집하고 분석하여, 펑크(blow-out) 타이어 차량 동적 거동 해석을 위한 구름저항력(rolling resistance), 셀프 얼라이닝 토크(self aligning torque), 코너링 강성(cornering stiffness), 반경방향 강성(radial stiffness)과 같은 관련 계수들의 적정값을 추정하였다. 이러한 타이어 펑크 관련한 입력계수들을 자동차 사고 해석 상용 프로그램에서 설정하여 타이어 펑크 효과를 구현한 시뮬레이션 해석을 수행하였다. 그리고, 정상 차량들 간의 다양한 충돌 형태들과 속도 등을 참조하여, 펑크 차량의 충돌 유형들을 구성하고 시뮬레이션 해석을 수행하여 충돌 특성을 구하였다. 본 연구에서 제시하는 타이어 펑크 혹은 손상에 대한 고려는 보다 신뢰성 있는 자동차 사고 재구성에 기여할 수 있을 것이다.