• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2003년도 제27회 추계학술대회
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• pp.67-67
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• 2003

It is crucial to minimize setup errors of a cancer treatment machine using a high energy and to perform precise radiation therapy. Usually, port film has been used for verifying errors. The Korea Cancer Center Hospital (KCCH) has manufactured digital electronic portal imaging device (EPID) system to verify treatment machine errors as a Quality Assurance (Q.A) tool. This EPID was consisted of a metal/fluorescent screen, 45$^{\circ}$ mirror, a camera and an image grabber and could display the portal image with near real time KIRAMS has also made the acrylic phantom that has lead line of 1mm width for ligh/radiation field congruence verification and reference points phantom for using as an isocenter on portal image. We acquired portal images of 10$\times$10cm field size with this phantom by EPID and portal film rotating treatment head by 0.3$^{\circ}$, 0.6$^{\circ}$ and 0.9$^{\circ}$. To check field size, we acquired portal images with 18$\times$18cm, 19$\times$19cm and 20$\times$20cm field size with collimator angle 0$^{\circ}$ and 0.5$^{\circ}$ individually. We have performed Flatness comparison by displaying the line intensity from EPID and film images. The 0.6$^{\circ}$ shift of collimator angle was easily observed by edge detection of irradiated field size on EPID image. To the extent of one pixel (0.76mm) difference could be detected. We also have measured field size by finding optimal threshold value, finding isocenter, finding field edge and gauging distance between isocenter and edge. This EPID system could be used as a Q.A tool for checking field size, light/radiation congruence and flatness with a developed video based EPID.

• 한국음향학회지
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• 제36권6호
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• pp.378-386
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• 2017

해양무기체계 연구개발 과정에 있어서 정량적 시험평가를 수행하기 위해 수중에서 기동하는 표적과 계측 장비간의 거리측정이 요구된다. 일반적으로 정확하게 동기화된 송 수신기 사이의 전송 시간차를 측정하는 단방향 ToA(Time of Arrival) 기법을 이용하여 목표물의 거리를 측정한다. 하지만 수신된 신호는 다중경로의 영향으로 왜곡되어 거리 추정 성능을 저하시킨다. 본 논문에서는 음선 기반의 블라인드 디컨볼루션 기법을 사용하여 수신된 각 데이터 프레임으로부터 시변하는 복합 수중 채널 함수를 추정하고 추정된 시변 전달 함수를 시역전하여 다중경로 현상을 제거한다. 제안된 기법으로 시뮬레이션 및 해상실험을 진행하였을 때, 기존의 ToA 기법보다 거리 추정 성능이 향상되는 결과를 확인하였다.

• 대한기계학회논문집A
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• 제34권10호
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• pp.1499-1505
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• 2010

유연성 공구를 가진 자기연마는 고경도 소재 및 자유곡면 형상 표면의 나노메터급 가공이 가능한 강점을 지닌다. 이러한 자기연마에서 자기연마입자는 시간적, 비용적 측면에서 단순 혼합형 입자가 유리하다. 그러나 단순혼합형 입자는 가공 중 공구로부터 쉽게 이탈하게 되어 가공 시간이 증가 할수록 매우 낮은 가공 효율을 가진다. 따라서 본 연구에서는 단순 혼합형 입자에 오일을 대신하여 실리콘 겔을 매개물로 사용하는 자기연마 입자를 연구하고 그 특성을 분석하였다. 그 결과 자기력 향상과 별개로 입자간 응집력을 높여 입자의 이탈을 줄여 표면거칠기의 향상에 효과가 높음을 확인 하였다. 그리고 실험계획법을 이용하여 고경도 소재인 텅스텐 카바이드의 실리콘 겔 자기연마에서 각 공정변수가 표면거칠기의 향상에 미치는 특성을 평가하고 이를 최적화 하였다.

• 한국산학기술학회논문지
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• 제15권6호
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• pp.3759-3765
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• 2014

본 연구의 목적은 동작관찰훈련이 만성 뇌졸중 환자의 균형능력에 미치는 영향을 알아보고자 실시하였다. 연구기간은 2013년 7월 8일부터 8월 10일까지 수행하였다. 연구대상자들은 무작위로 풍경사진관찰군(n=20)과 동작관찰군(n=20)으로 나누었다. 두 군은 각각 5분 동안 풍경사진 및 균형과 관련된 동작을 동영상으로 관찰하였다. 영상관찰 후, 두 군 모두 10분동안 균형훈련을 받았다. 훈련 세션은 2회 반복하여 하루 30분, 주 3회, 6주 동안 실시하였다. 그 결과, 풍경사진관찰군에 비해 동작관찰군에서 정적 및 동적균형이 유의하게 증가함을 확인할 수 있었다(p<.05). 결론적으로, 동작관찰과 균형훈련의 결합은 만성 뇌졸중 환자의 균형회복에 도움을 줄 것으로 생각된다.

• 한국태양에너지학회 논문집
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• 제32권5호
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• pp.41-51
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• 2012

Heliostat field is the most important subsystem in the tower type solar thermal power plant since its optical performance affects the total system efficiency most significantly while the construction cost of it is the major part of total construction cost in such a power plant. Thus a well designed heliostat field to maximize the optical efficiency as well as to minimize the land usage is very important. This work presents methodology, procedures and result of heliostat filed design for 200kW solar thermal power plant built recently in Daegu, Korea. A $2{\times}2(m)$ rectangular shaped receiver located at 43(m) high and tilted $28^{\circ}$ toward heliostat field, 450 of heliostats of which the reflective surface is formed by 4 of $1{\times}1(m)$ flat plate mirror facet, and the land area having about $140{\times}120(m)$ size are used to form the heliostat field. A procedure to deploy 450 heliostats in radial staggered nonblocking formation is developed. Also the procedures to compute the cosine effect, intercept ratio, blocking and shading ratio in the field are developed. Finally the heliostat filed is designed by finding the optimal radial distance and azimuthal spacing in radial staggered nonblocking formation such that the designed heliostat field optical efficiency could be maximized. The designed heliostat field has 77% of annual average optical efficiency, which is obtained by annually averaging the optical efficiencies computed between the time of where sun elevation angle becomes $10^{\circ}$ after sunrise and the time of where sun elevation angle becomes $10^{\circ}$ before sunset in each day.

• 한국초등과학교육학회지:초등과학교육
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• 제33권1호
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• pp.82-94
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• 2014

The purpose of this study is to develop teaching program which utilizes emotional intelligence elements as a measure to stimulate the motive and scientific attitude of learners and examine the effect of its application. The target unit for this study is 'world of plants' in the fourth grade of elementary school, and the teaching program is composed of 3 stages including I(encounter with myself), S(encounter with science), and U(encounter with friends). The teaching program is organized in the way to reflect 5 emotional intelligence elements including self-awareness, self-regulation, self-motivation, sympathy, and personal relations properly according to each stage of teaching program. The result of applying this program into actual classrooms is as follows. First, it is proven that the teaching program actually helps improving the motive of learners to study science. The emotional intelligence takes a role of positive motive for thinking, and the learners monitor their emotion and behavior patterns by using a mirror notebook to reduce their anxiety about science. Second, it is proven that the teaching program changes the science related attitude of learners positively. The emotional intelligence elements help the learners to create friendly feeling toward science subject and have a friendly attitude toward science and a sense of expectancy to science class. Third, it is proven that the teaching program contributes to the improvement of learners' science study achievement. The emotional intelligence takes an important role in improving the learners' science study achievement through the role of adjusting and controlling the recognition capability. However, emphasizing the emotional intelligence excessively also has a risk to break the balance between emotion and recognition, so it is considered that the balanced approach should be applied.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.1093-1096
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• 2003

본 논문에서는, CMOS APS Image Sensor 내에 포함되어 회로의 면적을 줄인 새롭게 제안된 CMOS Bandgap Reference Bias Generator (BGR)를 온도 및 방사능에 대한 응답을 실험하였다. 제안된 BGR 회로의 설계 목표는 V/sub DD/는 2.5V이상이고, V/sub ref/는 0.75V ± 0.5mV 마진을 가지게 하는 것이다. 제안된 BGR회로는 Level Shifter를 갖는 Differential OP-amp단과 Feedback-Loop를 가지는 Cascode Current Mirror를 사용하여 저전압에서도 동작을 가능하게 하였으며, 높은 출력저항 특성을 가지도록 하였다. 제안된 BGR회로는 하이닉스 0.18㎛ ( triple well two-poly five-metal ) CMOS 공정을 이용하여 Test Chip을 제작하였다. 온도의 변화와 Co-60 노출조건 하에서 Total ionization dose (TID) effect된 BGR회로의 V/sub ref/를 측정하여, 이를 평가하였다. 온도에 대한 반응은, 25℃ 일 때의 V/sub ref/에 대해, 각각 45 ℃에서 0.128%. 70℃에서 0.768% 변화하였다. 그리고 온도가 25℃일 때 50krad와 100krad의 방사능을 조사 하였을 경우, V/sub ref/는 각각 2.466%, 그리고 4.612% 변화하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권2호
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• pp.264-271
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• 2011

The effect of replacement of fish meal (FM) in diets with sand smelt meal (SSM) on fatty acid composition of carp fry, Cyprinus carpio, was examined. Five isonitrogenous and isoenergetic (38% crude protein, $15.75\;kJ\;g^{-1}$) diets replacing 0, 25, 50, 75, and 100% FM protein by SSM protein were formulated. Each diet was randomly allocated to triplicate groups of fish in aquaria, and each aquarium was stocked with 20 fish (initial average weight of $0.300{\pm}0.65\;g\;fish^{-1}$). Fish were fed twice daily to apparent satiation for 13 weeks. Results indicated that final weight, specific growth rate and feed efficiency ratio of fish fed with different SSM replacement diets did not differ significantly (p>0.05) from fish fed the control diet, except for 100% SSM level. No significant differences were noted among experimental treatments on dry matter, protein, lipid and ash contents of the fish body composition (p>0.05). Fatty acid analysis showed that saturated fatty acids in fish muscle significantly decreased, but monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) did not change with increasing dietary SSM. However, some changes also could be observed for some particular fatty acids in experimental fish. For example, the amounts of 15:0, 17:0, 18:1n-7, 18:2n-6 and 22:5n-3 significantly increased, but 16:0, 18:1n-9, 18:3n-3 and 20:1 n-9 significantly decreased with increasing dietary SSM. Total n-6 PUFA increased with increasing dietary SSM, but total n-3 PUFA were not changed in muscle of fish fed the experimental diets. The ratio of n-3 to n-6 was not affected significantly in muscle of fish fed the experimental diets containing different proportions of SSM, including the control diet.

• 한국정밀공학회지
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• 제18권11호
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• pp.51-57
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• 2001

A light beam reflected from a machined surface generally containes information concerning about its surface roughness. This study examines and proposes a surface roughness measurement technique for on-machine measurement of machined surfaces. The technique is based on the measurement of a reflected laser beam pattern and the statistical analysis of its light intensity distribution. The surface roughness was found to be closely related to the standard deviation of the light intensity on the primary axis of the reflected pattern. An image acquisition device is made up of a laser diode, a half mirror, a screen, and a CCD camera. The exact image with the primary and secondary axes of a reflected laser beam pattern is calculated through such image processing algorithm as thresholding, edge detection, image rotation, segmentation, etc. A median filter and a surrounding light correction algorithm are improve the image quality and reduce the measuring error. Using the developed measuring device the effect of screen materials and workpiece and workpiece materials was investigated. Experimental results regarding to relatively high-quality surfaces machined by grinding, polishing, lapping processes have shown the measurement error is within 10% in the range of $0.1{mu}m~0.8{\mu}m R_q.$Therefore, the proposed method is thought to be effectively used when quick measurements is needed with workpieces fixed on the machine.

• 대한기계학회논문집A
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• 제35권12호
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• pp.1641-1646
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• 2011

자기연마공정은 유동성이 높은 연마입자를 활용하기 때문에 곡면 및 그루브 형상에도 적용이 가능한 장점을 지니고 있다. 본 연구에서는 제 2세대 자기연마법을 활용하여 그루브 형상에 대한 자기연마가공 특성을 평가하여, 이를 향후 연료전지 채널과 같은 3차원 형상의 자기연마에 활용하고자 한다. 실험은 최대 1.5mm 깊이의 그루브에 대해 자기연마가공 후 슬롯부 및 랜드부의 표면거칠기 변화를 관찰하였다. 그 결과 랜드부의 길이가 증가하고 그루브의 깊이가 깊어질수록 랜드부의 표면거칠기 향상정도는 높아졌다. 또한 슬롯부의 표면거칠기 향상정도는 랜드부와 슬롯부의 길이비가 증가하고 그루브의 깊이가 깊어질수록 감소하는 경향을 나타내었다. 마지막으로 자기연마가공을 통해서 그루브의 형상에는 큰 변화없이, 그루브의 모서리에 생성된 버를 효과적으로 제거할 수 있었다.