• 동력기계공학회지
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• 제20권6호
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• pp.27-33
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• 2016

BLDC motors have the strong point of allowing high-efficiency operation, yet with the weak point of requiring position information for operation. Moreover, there have recently been frequent cases where the product differentiation of even a cheap BLDC motor demanded a high level of control performance similar to that of a controller using a high-precision position sensor. This paper proposes low cost position sensor that enables the acquisition of rotor position information based on index and incremental PWM, using a single position sensor instead of an expensive incremental encoder or a cheap 3 phase hall sensor. The characteristic of the proposed encoder is that index information at every $60^{\circ}$ of electrical angle is inscribed on the encoder disk, as well as a multiple number of values representing information about PWM, which is obtained by modulating information about the electrical angle of the rotor that has the resolution of $60^{\circ}$. Such a method has the characteristic of enabling the acquisition of high-precision position information based on the information about a multiple number of PWM waveforms and counter values that have all been inscribed on the encoder disk for each $60^{\circ}$ range. The feasibility of the proposed new encoder was verified by fabricating a prototype encoder generating 240 pulses, followed by confirming its performance using Micom's capture and software counter functions.

• 한국안광학회지
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• 제13권4호
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• pp.121-126
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• 2008

목적: 단안 과교정 및 저교정으로 유발된 부동시에서 정상적인 양안시기능을 유지하기 위해 필요한 최소한의 교정도수를 알아보고자 하였다. 방법: 안질환의 병력이 없는 20대의 성인 남녀를 대상으로 우위안 및 비우위안에 각각 과교정 및 저교정으로 부동시를 유발한 후 40 cm의 근거리에서 Titmus-fly stereotest 시표로 입체시를 측정하였다. 결과: 우위안 또는 비우위안에 구면렌즈를 부가하여 부동시를 유발한 경우, 가입도수의 증가에 따라 입체시는 감소하였으며 특히 (+)구면렌즈 가입에 따른 최초의 입체시 감소는 (-)구면렌즈 가입에 의한 입체시 감소보다 현저하였다. 또한 우위안에 유발시킨 부동시의 경우가 비우위안에 유발시킨 부동시보다 입체시 감소의 정도가 두드러졌다. 결론: 유발된 부동시에서 입체시는 비우위안을 완전교정하고 우위안에 (+)구면렌즈 도수를 증가시킬수록 두드러지게 감소하였다.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2966-2970
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• 2015

최근 태양광발전은 정부의 재생에너지 지원책에 의해 널리 보급되고 있다. 하지만 발전효율은 태양전지 모듈이 일정온도보다 높게 유지될 때 떨어진다. 따라서 일정온도 이하로 유지하는 것이 필요하다. 본 논문에서는 태양전지 모듈의 효율을 개선하기 위해서 지열교환장치를 개발하였다. 지열교환장치는 태양전지의 열 흡수판과 열전도판 그리고 방열기로 구성된다. 태양전지 모듈의 열은 지열교환 장치에 의해 땅속으로 방열한다. 결과적으로, 지열교환장치는 태양전지모듈의 발전량을 증가시키며, 실험결과는 발생전력이 약 36% 증가함을 보여 주고 있다.

• 한국연초학회지
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• 제12권2호
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• pp.91-101
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• 1990

A field experiment was conducted to find out the effects of field productivity, variety and nitrogen rate on the yield, quality, chemical constituents and physical properties of burley cured leaf in three field with different productivity(Degree of field productivity: A ; high, B ; medium, C : low) during successive two years(1988~89). The yield and quality were remarkably lowered when nitrogen fertilizer being applied much in low productive field. As compared with Burley 21, KB101 showed high yield, particularly the yield of KB101 in low productive field was relatively high. The effect of nitrogen rate on the yield was somewhat different according to field productivity and production year. When the nitrogen fertilizer being applied above 22.5kg/10a, the added nitrogen had no effect on the yield. Total nitrogen content of cured leaf grown in low productive field was high while total alkaloid was low, therefore total alkaloid/total nitrogen ratio was remarkably low. The lightness, red and yellow color of cured leaf grown in low productive field was remarkably low. As compared with Burley 21, the contents of total alkaloid and total nitrogen and shatter resistance index of cured leaf was somewhat low, while the filling power, lightness, red and yellow color were slightly high. Total nitrogen content of cured leaf was increased remarkably by nitrogen addition, but total alkaloid was not increased though the nitrogen fertilizer being applied above 22.5kg/10a. The filling power and shatter resistance index of cured leaf grown in high nitrogen plot, and the lightness and yellow color were low while the red color was relatively high. It comes into question that the visual quality being increased as well as increment of yield and nitrogenous compounds by nitrogen addition in high productive field. In low productive field, it is considerable that nitrogen addition for high yield should be prohibited because it causes the decrement of yield and quality, on the contrary.

• 우울조울병
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• 제16권3호
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• pp.169-177
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• 2018

Objectives : Despite the lack of domestic research, eating alone has been reported to be related to depression. We investigated correlation between eating alone, and depression, among women age 65 and older. Methods : Among women registered in the Korea National Health and Nutrition Examination Survey data, 1,119 elderly in 2014, and 1,189 in 2016, were analyzed. Eating alone and the degree of depression were assessed, using a questionnaire and the Patient Health Questionnaire-9 respectively. The relationship between eating alone and depression, was analyzed using multilevel logistic regression. Results : In 2014 data, eating alone had significant effect on depression, as the explanatory power is increased to 30.4% in a 'three meals eating alone a day' group (${\beta}=0.128$, p<0.05), when the eating alone parameter is added to demographic factors and health characteristics. In 2016, exploitation of 'the frequency of eating alone' variable led to increment of explanatory power to 22.3%, that was not statistically significant. Conclusion : The result of this study suggests that eating alone among women age 65 and older, was a risk factor of depression in 2014, and is becoming a new life pattern as a social and cultural phenomenon in 2016.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.719-722
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• 2016

현재 산업 분야 전반에 걸쳐 다양한 IoT 기술들을 접목하려 하고 있다. 그러나 센서 디바이스, 게이트웨이, 네트워크 서버, 그리고 어플리케이션 서버로 구성되는 복잡한 IoT 시스템 구조는 구현 상의 어려움과 설치 비용의 증가를 초래하고 이로 인해 소규모 네트워크 환경이 필요한 산업 분야에서 IoT 도입을 저해하는 결과로 나타나고 있다. 이에 따라, 본 논문에서는 소규모/저비용의 IoT 환경이 필요한 산업분야에서 활용될 수 있는 시스템 구조를 제안 한다. 또한 RF433 모듈을 이용한 무선 센서 네트워크, 아두이노 윤을 활용한 게이트웨이, 그리고 APM (Apache, PHP, MySQL)을 적용한 어플리케이션 서버를 구현하고 센서 디바이스의 효율적인 전력관리 방안을 제시한다.

• 핵의학기술
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• 제14권1호
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• pp.40-45
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• 2010

Purpose: Recently, the performance of the X-ray tube was very much improved by the power generation of the technology. However, the overload of equipment is occurred by the increment of the equipment operating time according to the increment of the examination number of cases. The X-ray dose can change by heat occurrence of the X-ray tube due to this. Moreover, the change of the bone mineral density value is possible to occur. Therefore, We tries to whether the change of the bone mineral density value of each equipment according to the difference of the examination number of cases and operating time occur or not. Materials and Methods: The BMD value was measured by the Aluminum Spine Phantom and the European Spine Phantom in each equipment, in order to find out about the difference of the time general classification bone mineral density value by using the Dual energy X-ray absorptiometry. And after scanning each phantom by using X-ray dose meter (Unfors Mult-O-Meter), a dose was measured by the same condition. As to, an average and standard deviation were found and the change of each equipment much BMD value was compared and it evaluated. Results: $Mean{\pm}SD$ of each equipment by using the Aluminum Spine Phantom, A equipment was $1.174{\pm}0.002$, $1.171{\pm}0.005$, $1.173{\pm}0.005$, B equipment was $1.186{\pm}0.003$, $1.187{\pm}0.003$, $1.185{\pm}0.003$, C equipment was $1.180{\pm}0.003$, $1.182{\pm}0.004$, $1.183{\pm}0.002$, D equipment was $1.188{\pm}0.004$, $1.185{\pm}0.003$, $1.185{\pm}0.004$. By using the European Spine Phantom, A equipment was $1.143{\pm}0.006$, $1.153{\pm}0.009$, $1.161{\pm}0.003$, B equipment was $1.134{\pm}0.004$, $1.13{\pm}0.008$, $1.127{\pm}0.015$, C equipment was $1.143{\pm}0.006$, $1.134{\pm}0.01$, $1.133{\pm}0.006$, D equipment was $1.14{\pm}0.001$, $1.122{\pm}0.002$, $1.131{\pm}0.008$, altogether included in the normal range. Conclusion: There was no significant change of the BMD value of using a phantom by time zones. Therefore, if the quality control is made to use the extent management method of the equipment for beginning in the present application, the reliability of the BMD equipment will be able to be enhanced.

• 대한전자공학회논문지SD
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• 제45권5호
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• pp.71-81
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• 2008

본 논문에서는 새로운 On-Chip 버스로 다중처리 기반의 GALDS 버스 구조를 제안하였고 성능을 검증하였다. 제안된 GALDS 버스 구조는 멀티 마스터 멀티 슬레이브의 다중 처리를 지원하는 세그먼트(segment) 기반의 고성능의 양방향 다중처리 버스 구조(bi-direction multitasking bus architecture)이다. 또한, 시스템의 태스크(task) 분석에 의해서, 버스는 버스 동작 주파수의 배수 값을 갖는 주파수 사이에서 각각의 IP에 최적화된 동작 주파수를 선택하기 때문에 전체 전력 소모를 줄일 수 있다. 서로 다른 동작 주파수를 입력받은 IP들 간의 효율적인 데이터 통신을 위하여, 본 구조에서는 비동기 양방향 FIFO를 기반으로 하는 비동기 Wrapper 설계하였다. 또한, 버스 세그먼트의 추가만으로 시스템의 쉬운 확장이 가능하기 때문에, 제안된 구조는 IP 재사용 및 구조적 변경이 용이한 장점을 갖는다. 제안된 버스의 검증을 위해 4-마스터/4-슬레이브를 가지는 4-세그먼트의 버스와 비동기 Wrapper를 Verilog HDL을 이용하여 구현하였다. 버스의 다중처리동작 검증은 버스와 IP의 동작 주파수 비가 1:1, 1:2, 1:4, 1:8인 경우를 기준으로 시뮬레이션을 통해 마스터 IP에서 슬레이브 IP 사이의 데이터 읽기 및 쓰기 전송 동작을 확인하였다. 데이터 전송은 Advanced Microcontroller Bus Architecture(AMBA)과 호환 가능한 16 Burst Increment 모드로 하였다. 제한된 GALDS 버스의 최대 동작 지연시간은 쓰기 동작 시 22 클럭, 읽기 동작 시 44 클럭으로 확인되었다.

• 드라이브 ㆍ 컨트롤
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• 제20권4호
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• pp.115-122
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• 2023

This study utilized a discrete element method (DEM) simulation, as one of the virtual field trials, to predict the impact of tillage depth on the rotary blade shaft during rotavator tilling. The virtual field for the simulation was generated according to soil properties observed in an actual field. Following the generation of particles for the virtual field, a sequence of calibration steps followed to align the mechanical properties more closely with those of real soil. Calibration was conducted with a focus on bulk density and shear torque, resulting in calibration errors of just 0.02% for bulk density and 0.52% for shear torque. The prediction of the load on a rotary tiller's blade shaft involved a three-pronged approach, considering shaft torque, draft force, and vertical force. In terms of shaft torque, the values exhibited significant increases of 42.34% and 36.91% for every 5-centimeter increment in tillage depth. Similarly, the vertical force saw substantial growth by 40.41% and 36.08% for every 5-centimeter increment. In contrast, the variation in draft force based on tillage depth was comparatively lower at 18.49% and 0.96%, indicating that the effect of tillage depth on draft force was less pronounced than its impact on shaft torque and vertical force. From a perspective of agricultural machinery research, this study provides valuable insights into the DEM soil modeling process, accounting for changes in soil properties with varying tillage depths. These findings are expected to be instrumental in future agricultural machinery design studies.

• 생명과학회지
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• 제16권1호
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• pp.114-119
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• 2006

저출력 적외선 레이저가 손상된 말초신경의 재생에 미치는 영향을 알아보기 위하여 흰쥐의 양측 좌골신경에 압궤손상을 준 뒤, 레이저 조사 기간에 따라 1, 3, 5 및 7주군으로 나누어 손상된 좌골신경의 신경전도속도와 진폭을 측정하여 신경재생의 정도를 관찰한 결과는 다음과 같았다. 좌골신경전도속도 검사에서 압궤손상 유발후에 손상전보다 유의하게 전도속도가 지연되었으나, 레이저를 조사한 실험측은 치료후 3주에 현저하게 신경전도 속도가 증가하였다. 좌골신경 진폭 검사에서 압궤손상 유발후에 손상전보다 유의하게 진폭이 감소하였으나, 레이저를 조사한 실험측은 치료후 3주에 복합근 활동전위의 진폭이 유의하게 증가하였다. 이상의 결과로 보아, 저출력 레이저 조사는 손상된 좌골신경의 기능회복에 있어, 주로 손상 초기의 회복속도에 영향을 주는 것으로 생각되는 바, 향후 말초신경 손상의 재활치료에 고려해야 할 것으로 생각된다.