• 한국해안해양공학회:학술대회논문집
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• 한국해안해양공학회 1997년도 정기학술강연회 발표논문 초록집 Annual Meeting of Korean Society of Coastal and Ocean Engineers
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• pp.31-38
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• 1997

The interest in numerically-generated, Boundary-Fitted Coordinate Systems (BFCS) arises from the need for conforming the boundaries of the region in such way that boundary conditions can be accurately represented. The parabolic approximation method in solving wave phenomena is known to have a great merit as time-saving method. However, the method shows a disagreement for the wide angle and behind the structure (omitted)

• 한국자동차공학회논문집
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• 제5권5호
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• pp.20-26
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• 1997

A System for reducing vehicle body roll by active control is developed. The stabilizer bar with hydraulic rotary actuator produces anti-roll moment which suppresses roll tendency. This reduction of roll improves the driving safety as well as the ride comfort. Vehicle test data shows considerable reduction of roll angle during steady-state turning. Also improvement of ride comfort is achieved by making the actuator freely rotatable, i.e. by connecting all chambers of actuator in normal driving conditions. A control algorithm using steering wheel angle and vehicle speed signal as input valve is applied. It is compared with signal of the G-sensor.

• 수산해양기술연구
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• 제22권1호
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• pp.24-28
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• 1986

The maneuverabilities of the M. S. PUSAN 402 are studied, based on maneuvering indices and the data obtained from her Z test. The results obtained are summarized as follows: 1. The maneuvering indices K' and T' of the M. S. PUSAN 402 are 1. 490, 1.030 at 10$^{\circ}$ Z test and 2.644, 1.153 at 20$^{\circ}$ Z test and 3.382. 1. 027 at 30$^{\circ}$ Z test respectively. The above calculated values K', T' showed that her maneuverabilities are more increased when the rudder is used to large angle than to smaIl angle. 2. As her maneuvering indices K' and T' at 10$^{\circ}$ Z test are higher than the standard maneuvering indices of fishing boats, her turning ability was found to be higher but her obeying ability lower. 3. When the M. S. PUSAN 402 took a turn at her 10$^{\circ}$ test, running distance was about 8.4 times her own length and didn't exceed the standard maneuvering distance, 5 to 11 times ship's own length, therefore she was considered to have good maneuverabilities syntheticaIly.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.685-690
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• 2000

In this study relationship between relief angles and chatter vibration in turning was examined by using the direct cutting test, in which the cutting depth of a tapered workpiece is varied continuously and the limiting depth of cut is measured at the time when chatter occurs. Test results reveal that 1) limiting depth of cut increases is proportion to side relief angles between 0$^{\circ}$ and 3$^{\circ}$, 2) limiting depth of cut does not show any evident change in spite of side relief angle increased from 3$^{\circ}$ to 12$^{\circ}$, 3) also limiting depth of cut does not change despite front angle change from 0$^{\circ}$ to 12$^{\circ}$.

• 한국운동역학회지
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• 제20권2호
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• pp.183-189
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• 2010

The balanced performance of dominant and non-dominant leg is very important to Taekwondo sparring. The purpose of this study was to investigate whether elite Taekwondo athletes would have balanced biomechanical performance and intra-limb coordination in executing different types of Taekwondo kicks. Twelve athletes(more than 10 year practice experience) participated in this study and performed six basic kicks(i.e., the front, roundhouse, side, back, thrashing, and turning-back kick). Results indicated no statistical difference on response time, peak kicking velocity, single limb vertical jump height, and angle-angle plot between dominant leg and non-dominant leg(p>.05). In conclusion, elite Taekwondo athletes had equivalent ability between dominant leg and non-dominant leg in performing Taekwondo kicks. This might be an advantage to elite athletes for Taekwondo sparring because they could use both leg without any restriction.

• Agricultural and Biosystems Engineering
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• 제6권2호
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• pp.47-53
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• 2005

AMachine vision is a promising tool for the autonomous guidance of farm machinery. Conventional CCD camera for the machine vision needs a desktop PC to install a frame grabber, however, a web camera is ready to use when plugged in the USB port. A web camera with a notebook PC can replace existing camera system. Autonomous steering control system of this research was intended to be used for combine harvester. If the web camera can recognize cut/uncut edge of crop, which will be the reference for steering control, then the position of the machine can be determined in terms of lateral offset and heading angle. In this research, a white line was used as a cut/uncut edge of crop for steering control. Image processing algorithm including capturing image in the web camera was developed to determine the desired travel path. An experimental vehicle was constructed to evaluate the system performance. Since the vehicle adopted differential drive steering mechanism, it is steered by the difference of rotation speed between left and right wheels. According to the position of vehicle, the steering algorithm was developed as well. Evaluation tests showed that the experimental vehicle could travel within an RMS error of 0.8cm along the desired path at the ground speed of $9\sim41cm/s$. Even when the vehicle started with initial offsets or tilted heading angle, it could move quickly to track the desired path after traveling $1.52\sim3.5m$. For turning section, i.e., the curved path with curvature of 3 m, the vehicle completed its turning securely.

• 대한기계학회논문집
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• 제10권6호
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• pp.807-813
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• 1986

본 연구에서는 국내에서 생산되고 있는 구상흑연주철을 이단으로 어니일링하 여 기타조직을 3가지(p$_{1}$:28.88% 페라이트, 63.5% 퍼얼라이트, p$_{2}$:49.7% 페 라이트, 42.2% 퍼얼라이트, p$_{3}$:71.26% 페라이트, 22.3% 퍼얼라이트)로 변화시켜 족삭에서 이차원절삭실험을 실시하여 기타조직에 따라 제절삭성(절삭력, 절삭비, 전단 각 및 침의 흐름속도)을 비교검토 하므로서 어니일링효과가 절삭성에 미치는 영향을 검토 연구하였다.

• 대한공간정보학회지
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• 제3권2호
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• pp.213-220
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• 1995

차량 항법 시스템에서 맵 매칭(map matching) 방법은 데드 레코닝(dead reckoning) 기법으로 구한 차량의 위치가 지도상의 도로위에 일치하지 않는 경우에 이를 도로위에 매칭(matching) 시키기 위한 방법이다. 본 논문에서는 교차로 부근에서 차량의 회전을 감지함으로서 센서 및 수치지도자료에 기인하는 위치오류를 보정할 수 있는 새로운 맵 매칭 알고리즘을 제안하였다. 제안된 알고리즘은 진행거리의 상대오차와 도로거리의 절대오차를 이용하여 교차로 지역의 범위를 설정하고, 설정된 지역에서 차량의 진행각을 감지하여 교차로에 연결된 각 도로에 대한 출발지점을 알아내고, 회전각과 진행각을 비교하여 새로운 위치를 알아내는 방법이다. 제안된 알고리즘의 효율성을 검증하기 위하여 거리센서로 속도센서를, 방향센서로서 광 자이로를 이용하여 휴대용 컴퓨터에 시스템을 구성하고, 대전지역을 시범지역으로 선정하여 알고리즘을 실험한 결과 그 유효성을 입증할 수 있었다.

• 한국수산과학회지
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• 제12권4호
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• pp.209-215
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• 1979

부산수산대학실습선 '새바다'(GT: 2,275.7ton)에 관한 조종성능을 구명하기 위하여, 실선에 의한 Z 조종시험을 한 결과를 요약하면 다음과 같다. 1. '새바다'호의 $10^{\circ}Z$시험에서의 선회성지수 K'값은 1.052, 추종성지수 T' 값은 0.815, $20^{\circ}Z$ 시험에서의 K'값은 0.925, T'값은 0.502, $30^{\circ}Z$ 시험에서의 K' 값은 0.877, T' 값은 0.441로서, 소타각사용시의 조종성능과 대타각사용시의 조종성을 비교하여 보면, 대타각을 사용할 때 보다 추종성을 좋아지나 선회성을 낮아진다는 것을 알 수 있다. 2. '새바다'호의 $10^{\circ}Z$ 시험에서의 선회성지수 K' 값과 추종성지수 T' 값은 어선의 표준식에 가까움으로 어선으로서 양호한 조종성능을 가지고 있다고 볼 수 있었다. 다만 길이와 크기에 비하여 K'값이 약간 적은 수치이며, $10^{\circ}Z,\; 20^{\circ}Z,\;20^{\circ}Z$ 시험에서의 회두각곡선의 overshoot angle이 약간 크므로 추종성은 좋으나 선회성은 낮은 편임을 알 수 있었다. 3. '새바다'호의 조종성능은 추종성에 비하여 선회성이 낮으므로 선회경도 크게 되며, 또한 대각도전타시에 비하여 선회성이 낮아지므로, 충돌이나 좌초를 회피하기 위하여 대각도전타를 할 경우에는 안전한게 접근거리를 크게 두어 한기전타하는 등 조선상주의를 요한다. 4. '새바다'호의 $10^{\circ}$시험에서의 1조작간항주거리하는 배 길이의 약 8.6배로서 일반선박의 조종성표준거리 $5\~11$배의 이내가 되므로 '새바다'호의 조종성능은 총합적으로 양호하다는 것을 알 수 있었다.

• International Journal of Fluid Machinery and Systems
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• 제4권4호
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• pp.360-366
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• 2011

Thin circular-arc blade is often used as a guide vane, a deflecting vane, or a rotating blade of low pressure axial-flow turbomachine because of its easy manufacture. Ordinary design of the blade elements of these machines is done by use of the carpet diagrams for a cascade of circular-arc blades. However, the application of the carpet diagrams is limited to relatively low cambered blade operating under optimum inlet flow conditions. In order to extend the applicable range, additional design data is necessary. Computational fluid dynamics (CFD) is a promising method to get these data. In this paper, two-dimensonal cascade performances of circular-arc blade are widely analyzed with CFD. The results have been compared with the results of experiment and potential theory, and useful information has been obtained. Turning angle and total pressure loss coefficients are satisfactorily predicted for lowly cambered blade. For high camber angle of $67^{\circ}$, the CFD results agree with experiment for the angle of attack less than that for shockless inlet condition.