• 대한전기학회논문지:시스템및제어부문D
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• 제51권12호
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• pp.571-576
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• 2002

This paper is to develop jumping ring system with three sensor arrays and to control levitated ring using dynamic neural mode. Placing an aluminum ring on the core and switching on an AC source causes the ring to jump in the air due to induced currents. The educational system is composed of 40th optical sensor array, encode circuit, 89C51 microprocessor and control board. The control board consists of power IC, and phase controller. Real time process is present to obtain a height of levitated ring for three different sensor arrays. Based on the educational system and the proposed dynamic neural mode, the height of levitation of the ring is controlled by reference signals. This paper focuses on real system controls using the dynamic neural mode with on line learning algorithm.

• 한국가시화정보학회지
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• 제12권1호
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• pp.30-34
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• 2014

Bluff bodies under the external periodic force vibrate at their own natural or forced frequency. Rectangular bodies or similar structures such as high-rise towers and apartments, and recently a well-cited application - offshore floating bodies, usually needs to reduce these vibrations for stability and the mode control. Therefore, this study is aiming to reduce or control the vibration of a structure by a passive control method, i.e., TLCD (Tuned Liquid Column Damper). Controlling a moving body with a TLCD based on a variety of the orifice shape has been preliminary studied. In order to get a proper control, an optimized study is made on the design of the orifice shape, which has internal plates with the holes. The results show the force acting on the body due to the periodic movement highly depends on the number of holes on the plate and the height of the water level. Therefore, the optimum shape of the orifice and the height of the water level should be confirmed by a series of experiments.

• 말소리와 음성과학
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• 제3권2호
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• pp.29-35
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• 2011

This paper examines several articulatory properties of /k/, known as a trigger of place assimilation as well as the object of post-obstruent tensing (/tk/), in comparison to non-assimilating controls (/kk/ and /kt/). Using EMMA, tongue body articulation in the place assimilation context robustly shows greater spatio-temporal articulation and lower jaw position. Results showed several characteristics. Firstly, constriction duration of the tongue body gesture in C2 of the assimilation context (/tk/) was longer than non-assimilating controls (/kk/ and /kt/). Secondly, constriction maxima also demonstrated greater constriction in the /tk/ sequences than in the control /kk/, but similar values with the control /kt/. In particular, results showed a significant relationship between the two variables - the longer the constriction duration, the greater the constriction degree. Lastly, jaw height was lower for the assimilating context /tk/, intermediate for the control /kk/, and higher for the control /kt/. Results suggest that speakers have lexical knowledge of place assimilation, producing a greater tongue body gesture in the spatio-temporal domains with lower jaw height as an indication of anticipating reduction of C1 in /tk/ sequences.

• 한국정밀공학회지
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• 제34권3호
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• pp.167-172
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• 2017

This study proposes a method for identifying correlations between tension and drop height for sessile droplets in a roll-to-roll processing system. The effect of tension and drop height on the contact angle of a sessile droplet is presented. Design of experiment (DOE) methodology and statistical analysis are used to define a correlation between the process parameters. The contact angle is decreased while increasing tension and drop height. The influence of the tension is less significant on the contact angle compared with the effect of the drop height. However, tension should be considered as a major parameter because it is not easy to fix with roll eccentricity and compensating speed of the driven roll. The results of this study show that the effect of tension on the contact angle of a sessile droplet is more important than drop height because the drop height is fixed when the process systems are determined.

• 한국측량학회지
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• 제13권2호
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• pp.237-244
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• 1995

본 연구에서는 수준점에 대한 GPS 관측결과로부터 WGS84 지오이드고 모델을 구성하고 Bi-linear방법, 회귀다항식 방법 및 삼각보간법을 사용하여 check points로 선정한 수준점에 대한 지오이드고를 산출하므로써 보간방법에 따른 보간정확도를 비교, 분석하였다. 또한 삼각점의 GPS 관측성과로부터 도출한 좌표변환계수를 적용하여 수준점의 Bessel 경 위도좌표를 구하고 수준점의 표고성과와 조합하여 수준점의 표고변환의 정확도를 검토하였다. 그 결과, 수준점의 WGS84지오이드고 및 정표고를 평균 20 cm의 편차로 결정할 수 있었다.

• 대한원격탐사학회지
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• 제28권2호
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• pp.227-235
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• 2012

InSAR (Interferometric SAR) 기법을 이용한 DEM 추출은 두 SAR 영상의 정합, 간섭도 생성, 위상 필터링, 위상 unwrapping, 고도변환, 좌표계 변환 등 매우 복잡한 단계를 필요로 한다. 본 연구에서는 unwrapped 위상을 고도값으로 변환하는 과정에 대한 정밀도 향상을 위한 알고리즘을 개발하였다. 개발된 알고리즘은 지구타원체를 고려하여 수정된 ambiguity 방법, Schw$\ddot{a}$bisch 방법과 더불어 두 SAR 자료의 궤도가 평행하지 않을 때 발생하는 오차를 현저히 줄일 수 있는 개선된 ambiguity 방법이다. JERS-1 궤도를 이용한 알고리즘 성능 분석을 통해 기존 ambiguity 알고리즘은 두 개의 SAR 영상 궤도가 평행하지 않은 경우, 간섭위상의 고도변환 과정 중에 약 40 m 이상의 오차가 발생할 수 있음을 확인하였다. 개발된 알고리즘은 JERS-1과 같은 위성궤도의 불안정 또는 ERS2-ENVISAT Cross-InSAR를 위한 궤도 제어 등 다양한 원인에 의해 발생할 수 있는 평행하지 않는 두 위성 궤도 자료의 간섭쌍을 이용한 정밀 InSAR DEM 생성에 매우 효과적으로 활용될 수 있다.

• 한국자동차공학회논문집
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• 제15권5호
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• pp.1-8
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• 2007

The present research is based upon the numerical analysis of a car windshield in order to represent the optimum design guide to improve the overall defrosting performance of the system. First, the control factors that highly affect the defrosting performance of a car windshield are chosen and afterwards, the optimum variables of each control factor are extracted out to analyze its performance. The main control factors for this research are respectively, the air injection angle of a defroster nozzle, the height of a nozzle outlet, and the ratio of the width to the height of a nozzle outlet. For such case when the air inlet angle is relatively small, the flow near the vicinity of the inner face of a windshield tends to expand. As a consequence, the heat transfer rate through the windshield decreases. Also, the height of a nozzle outlet is recommended to maintain its size to minimum. However, when the ratio mentioned before is designed less than unity, the defrosting performance decreases.

• 한국해양공학회지
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• 제16권2호
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• pp.53-59
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• 2002

This paper shows the experimental results controlling the height of surface and back bead in GMAW by analyzing the unexpected gaps between base metals produced in welding and by controlling welding velocity due to the variation of the gap between base metals in thin-plate welding. The back bead behavior and burn-through in I-type butt joint $CO_2$ welding of thin mild steel are analyzed in the views of short circuit time ratio and short circuit frequency. It is shown through experimental consideration that the short circuit time ratio method is more reasonable than the short circuit frequency method in analyzing the formulation of back bead under changing the gap between base metals. Based on the these results, welding manipulator is designed so as to satisfy the bead height control in real time by measuring the short circuit time ratio. To show the effectiveness of the developed bead formulation control system, the experiment is implemented under two welding conditions such as increasing gap from 0mm to 0.8mm and gradually increasing gap from 0mm to 1.2mm. The experimental results show that the bead formulation can be controlled uniformly in spite of the variation of the gap between base metals.

• 생물환경조절학회지
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• 제24권3호
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• pp.243-251
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• 2015

근권부 공기순환 덕트 냉방이 온도 및 생육에 미치는 영향을 구명하고자 고온기 파프리카((Capsicumannum.L. 'Veyron')을 코이어배지에서 수경재배하였다. 냉방시간처리는 24시간 연속 가동한 연속냉방(All-day), 17시부터 다음날 1시까지 8시간 냉방한 야간냉방(Night), 대조구인 냉방 무처리(Control) 등 3 처리하여 온실 상 하부 온도, 근권온도, 엽온, 과실 특성 및 기관 분배율을 측정하였다. 근권부 덕트 냉방하였을 때, 고온기(6월 ~8월) 온실하부(바닥으로부터 40cm)와 상부(바닥으로부터 180cm) 온도, 근권온도는 하강되었다. 대조구와 비교하여 온실하부/상부 온도 차이가 연속냉방에서는 $4.4{\sim}5.1^{\circ}C/2.1{\sim}3.1^{\circ}C$ 하강을, 야간냉방 처리에서는 $3.4{\sim}3.8^{\circ}C/2.2{\sim}2.7^{\circ}C$ 하강되었다. 근권온도는 온실 하부 온도 결과와 유사했으며, 연속냉방($22.8^{\circ}C$)> 야간 냉방($24.1^{\circ}C$) > 대조구($27.7^{\circ}C$) 순으로 온도가 낮았다. 연속냉방 처리에서 덕트 위치(통로, 베드하단)와 송풍 방향($45^{\circ}$, $90^{\circ}$, $180^{\circ}$)에 따른 온도 변화를 측정한 결과 덕트의 위치가 통로에 위치하고 송풍방향이 상향($45^{\circ}$) 또는 수평($180^{\circ}$)인 처리는 지상부 100cm까지의 수직 위치에 따른 온도 차이가 크지 않지 않으면서, 근권부위 온도인 지상 50cm 온도가 낮은 특징을 보였고 베드와 베드 공간 사이로 덕트 송풍 방향이 직각($90^{\circ}$)이였을 때는 바닥과 지상 50cm 부위의 온도가 높고, 지상 100cm 이상 200cm 부위 온도가 상대적으로 낮았다. 연속냉방 또는 야간냉방 처리했을 때 파프리카 엽온은 오후 7시가 오전 9시 보다 엽온 하강이 컸다. 과실 분배율은 대조구(24.4%)에 비해 연속냉방(48.6%)과 야간냉방(45.6%)에서 높았으며, 평균과중, 과수 및 수량도 연속냉방 처리에서 가장 높았다. 한편 야간냉방 처리에서도 고온기 평균 지상부 및 근권온도를 낮추었으나, 누적된 평균온도가 가장 낮은 연속냉방처리에서 과실로의 동화산물 분배율을 높여 파프리카 수량을 증가시킨 것으로 보인다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권7호
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• pp.1029-1035
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• 2005

A 3${\times}$4 factorial field experiment with a complete randomised split-plot design with four replicates was conducted from June 2002 to March 2003 at the experimental farm of the Nong Lam University, Ho Chi Minh City, Vietnam, to determine effects of different harvesting heights (10, 30 and 50 cm above the ground) and cutting intervals (45, 60, 90 and 285 days) on yield of foliage and tubers, and chemical composition of the foliage. Cassava of the variety KM 94 grown in plots of 5 m${\times}$10 m at a planting distance of 30 cm${\times}$50 cm was hand-harvested according to respective treatments, starting 105 days after planting. Foliage from the control treatment (285 days) and all tubers were only harvested at the final harvest 285 days after planting. Dry matter and crude protein foliage yields increased in all treatments compared to the control. Mean foliage dry matter (DM) and crude protein (CP) yields were 4.57, 3.53, 2.49, and 0.64 tonnes DM $ha^{-1}$ and 939, 684, 495 and 123 kg CP $ha^{-1}$ with 45, 60, 90 and 285 day cutting intervals, respectively. At harvesting heights of 10, 30 and 50 cm the DM yields were 4.27, 3.67 and 2.65 tonnes $ha^{-1}$ and the CP yields were 810, 745 and 564 kg $ha^{-1}$, respectively. The leaf DM proportion was high, ranging from 47 to 65%. The proportion of leaf and petiole increased and the stem decreased with increasing harvesting heights and decreasing cutting intervals. Crude protein content in cassava foliage ranged from 17.7 to 22.6% and was affected by harvesting height and cutting interval. The ADF and NDF contents of foliage varied between 22.6 and 30.2%, and 34.2 and 41.2% of DM, respectively. The fresh tuber yield in the control treatment was 34.5 tonnes $ha^{-1}$. Cutting interval and harvesting height had significant negative effects on tuber yield. The most extreme effect was for the frequent foliage harvesting at 10 cm harvesting height, which reduced the tuber yield by 72%, while the 90 day cutting intervals and 50 cm harvesting height only reduced the yield by 7%. The mean fresh tuber yield decreased by 56, 45 and 27% in total when the foliage was harvested at 45, 60 and 90 day cutting intervals, respectively. It is concluded that the clear effects on quantity and quality of foliage and the effect on tuber yield allow alternative foliage harvesting principles depending on the need of fodder for animals, value of tubers and harvesting cost. An initial foliage harvest 105 days after planting and later harvests with 90 days intervals at 50 cm harvesting height increased the foliage DM and CP yield threefold, but showed only marginal negative effect on tuber yield.