• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.901-905
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• 2005

Monte Carlo localization is known to be one of the most reliable methods for pose estimation of a mobile robot. Much research has been done to improve performance of MCL so far. Although MCL is capable of estimating the robot pose even for a completely unknown initial pose in the known environment, it takes considerable time to give an initial estimate because the number of random samples is usually very large especially for a large-scale environment. For practical implementation of the MCL, therefore, a reduction in sample size is desirable. This paper presents a novel approach to reducing the number of samples used in the particle filter for efficient implementation of MCL. To this end, the topological information generated off- line using a thinning method, which is commonly used in image processing, is employed. The topological map is first created from the given grid map for the environment. The robot scans the local environment using a laser rangefinder and generates a local topological map. The robot then navigates only on this local topological edge, which is likely to be the same as the one obtained off- line from the given grid map. Random samples are drawn near the off-line topological edge instead of being taken with uniform distribution, since the robot traverses along the edge. In this way, the sample size required for MCL can be drastically reduced, thus leading to reduced initial operation time. Experimental results using the proposed method show that the number of samples can be reduced considerably, and the time required for robot pose estimation can also be substantially decreased.

• 제어로봇시스템학회논문지
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• 제22권5호
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• pp.382-388
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• 2016

When Flat Panel Display (FPD) is made with backlight module, such as LED TV, it inherently suffers from the non-uniform backlight luminance problem that results in un-even brightness distribution throughout the TV screen. If the luminance of each pixel location of a TV screen as a function of the driving voltage can be measured, it can be used to compensate the non-uniformity of the backlight module. We use a carefully calibrated imaging system to take pictures of a TV screen at different levels of brightness and generate the compensation functions for the driving circuitry to correct the luminance level at each pixel location. Making use of the fact that the luminance of the screen is normally brightest at around the center of the screen and gradually decreases toward the border of the screen, the luminance of the whole TV screen is approximated by a mathematical function of the pixel locations. The parameters of the function are computed in the least square sense by the values of both the pixel luminance sent from the driving circuit and the grayscale value measured from the image taken by the imaging system. To justify the correction system, a simple second order polynomial function is used to approximate the luminance across the screen. When the driving circuit voltage is corrected according to the measured function, the variance of the screen luminance is reduced to one tenth of the one measured from the un-corrected TV screen.

• 한국컴퓨터정보학회논문지
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• 제25권7호
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• pp.125-134
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• 2020

본 연구에서는 Q방법론을 적용하여 대학생을 대상으로 학과 점퍼에 대한 주관적 평가와 인식 유형별 특성을 알아보고자 하였다. 대학생의 학과 점퍼에 대한 태도 및 인식유형은 3유형으로 분류되었다. 제1유형의 경우 학과 점퍼는 학과에 대한 소속감을 주고 학과를 홍보하는 역할을 한다고 인식하였다. 또, 학과 점퍼 착용 시 행동을 조심하지만, 활동이 편하고 주변 사람들의 좋은 평가를 하여 나의 신뢰감을 높여주는 효과가 있다고 생각하였다. 제2유형의 경우 학과 점퍼는 활동하기 편하며 유행을 따르지 않는 무난한 디자인이라 만족스럽고, 등교 시 늘 착용하였다. 제3유형은 학과 점퍼 착용 시 동질감과 소속감을 주고, 학과 점퍼가 유행을 따라가는 스타일이면 좋겠고 학과 점퍼 착용에 긍정적인 유형이다. 대학생들의 학과 점퍼는 유니폼으로 학과의 이미지나 상징성을 잘 나타내고, 활동량이 큰 대학생들의 신체적 특징을 반영하여 맞음새가 우수한 학과 점퍼가 개발되어야 할 것으로 생각된다.

• 대한전자공학회논문지SP
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• 제48권3호
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• pp.99-105
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• 2011

본 논문에서는 수정된 segment maxima을 기반으로 한 색역 추정 방법을 제안한다. Segment maxima은 CIELab 공간을 일정한 간격으로 분할하고, 각 분할된 영역의 최외각 측정 데이터를 계산하여 색역을 추정하는 기법이다. 그러나 이 방법은 색공간의 분할 개수에 따라서 지역적인 색역 왜곡이 나타나 색역 사상시에 컬러 결점(color artifact)을 발생시킨다. 색공간 분할 개수가 적으면 높은 채도 부근에서 추정된 색역 정보가 분실되어 컬러 컨투어(color contour) 현상이 발생한다. 이와 반대로 색공간 분할 개수가 많으면 CIELab 밝기 축 부근에서 색역이 오목하게 되는 왜곡이 발생한다. 이러한 지역적인 색역 왜곡은 색역 사상시 결과 영상에 컬러 결점이 유발한다. 제안한 논문에서는 실험을 통하여 측정한 데이터 수에 따른 적절한 색공간 분할개수를 설정하여 높은 채도 부근에 색역 축소를 줄이며, 오목하게 나타나는 지역적인 색역 왜곡을 다양한 색역 분할에 따른 색역 경계 서술자(gamut boundary descriptor) 비교를 통해 이를 수정하는 방법을 제안하였다. 실험을 통해 제안한 방법이 기존의 segment maxima보다 정확한 장치의 색역을 추정할 수가 있었고, 결과 영상에서도 컬러 컨투어나 반점과 같은 컬러 결점이 줄어듬을 확인 할 수 있었다.

• 한국주거학회논문집
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• 제18권1호
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• pp.35-42
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• 2007

This study aims at examining the actual conditions of lighting environment and the consciousness and responses of residents with the living room of apartment house, grasping the problems of existing lighting methods, offering the lighting environment design standard in harmony with the various demands of residents, functions of living room space, life in living room and interior decoration and then pursuing the comfortable living environment. As the scope and methods of research for these, existing research methods are examined through the consideration of preceding researches and the basic outline of this research is constructed. Questionnaire survey is conducted with six apartment complexes including Kumho district, Munhung district, Sangmu district, Unnam district, Ilkok district and Chumdan district, the problems and improvements of lighting environment conditions are examined, conception and selection of lighting equipment design image are made, lighting equipment design of living room is suggested and the expected effects of lighting equipment ordering method are arranged as follows. As a result of examining and analyzing the lighting environment of living room in existing apartment houses, it is known that the conditions of existing lighting environment considered uniform lighting plan for functional sides of each room which didn't consider the various living behaviors and preference of residents and while the degree of interior decoration design is actually positive. Accordingly it seems that the lighting equipment ordering which considers the various preferences of residents is applied as the means for comfortable lighting environment, the interior environmental mood will be greatly improved.

• Journal of Positioning, Navigation, and Timing
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• 제7권1호
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• pp.37-42
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• 2018

This paper proposed a microstrip antenna that can perform jamming of satellite signals from the GPS L5, GLONASS G3, BDS B2 frequency bands (1164 - 1217 MHz) that are employed mainly for military purposes among the GNSS frequencies using unmanned aircrafts over the enemy's sky in time of emergency. The single element in the proposed antenna can be easily mounted to unmanned aircrafts. This study analyzed the characteristics of miniaturization and beam of radiating elements by applying the image theories and perturbation effect to satisfy the uniform level at ${\pm}45^{\circ}$ of beam steering goal due to the phase delay after antenna array. The designed microstrip antenna had a miniaturized radiating element area (x-y plane), which was reduced by 76.3% compared to that of basic microstrip antenna, and its beam width was $190^{\circ}$ in the E-plane and $140^{\circ}$ in the H plane. In addition, the simulation was conducted to determine the characteristics due to the phase delay by arranging the designed single microstrip antenna by $1{\times}4$ array and the results showed that beam steering of ${\pm}45^{\circ}$ is possible in the H-plane on the basis of $0^{\circ}$. Thus, the proposed antenna was verified to be effective in satellite signal jamming in the air as it was attached to the lower end of unmanned aircrafts.

• 한국의류산업학회지
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• 제5권5호
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• pp.443-452
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• 2003

People have been getting interested in the Orientalism and it has come up in various areas due to scientific progress. I designed uniforms, which was simple and western, to show its symbolic meanings in the Orientalism. And I have been trying to generalize uniforms with originality and beauty. I have studied the process of the Orientalism and its changes and transitions, concepts and origins in history. And I applied the styles of Korean, Japanese and Chineses costume on it. I also referred to characters of uniforms, which already had images of Korea, Japan and China. Firstly, Korean styles have a contrast in colors by application of Taegeuk. And they gave lines with dark colors in black one-piece dress. This makes people who are wearing looking slimmer. White ramie top looks fresh and Korean traditional tie called Maedeup is set up for button. Secondly, Japanese styles were mainly Kimono style, one piece. They changed into two pieces designed to be active. So, it has emphasized the image of Kimono with Obi at the waist. Thirdly, Chinese styles basically are Chipao style, which has a Chinese collar and a long skirt, which has opening. But they gradually changed into short skirts and more open in the chest. For one of them, they gave lines in the side of chest, sleeves and skirt to be more natural. The costumes have kept their positions as a part of mass society that grows and changes with speed. And oriental uniforms are not just uniforms any longer only for work. It is quite symbolic like a 'second face' as it represents images for their countries and enterprises.

• Nuclear Engineering and Technology
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• 제44권1호
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• pp.53-60
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• 2012

The aim of this study was to explore the spatial and energy resolutions of a PET scanner that we have recently developed. The scanner, which consists of six detector modules with 1-layer LGSO crystals, has a hexagonal configuration with a faceto- face distance of 86.4 mm between two opposite PET modules; such properties facilitate the imaging of small animals. A $^{22}Na$ point source was employed to estimate horizontal and vertical spatial resolutions. To assess the energy resolution, a uniform $^{18}F$ cylindrical phantom was scanned. A software-based spectrum analysis of list-mode data was used to assign a local energy window centered on the photopeak position for every single crystal. For the image reconstruction, an ML-EM algorithm was used. The spatial resolutions at the center of the scanner were 0.99 mm in the horizontal direction and 1.13 mm in the vertical direction. The energy resolution averaged over each PMT ranged from 13.3%-14.3%, which gave an average value of 13.8%. These results show that this simple system is promising for small animal imaging with excellent spatial and energy resolutions.

• Korea-Australia Rheology Journal
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• 제14권3호
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• pp.107-114
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• 2002

Residual stress distribution in injection molded short fiber composites is determined by using the layer-removal method. Polystyrene is mixed with carbon fibers of 3% volume fraction (4.5% weight fraction) in an extruder and the tensile specimen is injection-molded. The layer-removal process, in which removing successive thin uniform layers of the material from the surface of the specimen by a milling machine, is employed and the resulting curvature is acquired by means of an image processing. The isotropic elastic analysis proposed by Treuting and Read which assumes a constant Yaung’s modulus in the thickness direction is one of the most frequently used methods to determine residual stresses. However, injection molded short fiber composites experience complex fiber orientation during molding and variation of Yaung’s modulus distribution occurs in the specimen. In this study, variation of Yaung’s modulus with respect to the thickness direction is considered for calculation of the residual stresses as proposed by White and the result is compared with that by assuming constant modulus. Residual stress distribution obtained from this study shows a typical stress profile of injection-molded products as reported in many literatures. Young’s modulus distribution is predicted by using numerical methods instead of experimental results. For the numerical analysis of injection molding process, a hybrid FEM/FDM method is used in order to predict velocity, temperature field, fiber orientation, and resulting mechanical properties of the specimen at the end of molding.

• 펄프종이기술
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• 제34권2호
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• pp.1-12
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• 2002

Starch dissolved in paper-mill wastes, either as a result of poor retention on the paper web or recycling of surface-treated broke, was a major pollutant Laboratory tests were performed by using different kinds of starch as a surface treatment. It was concluded that the use of cationic starch can positively affect the level of starch dissolved in liquid effluents. When cationically modified starches were used for surface sizing, the starch was tightly bound to the paper fibers, it was not removed during the repulping of broke. The result of mill trial in fine paper manufacture for the application of low-viscosity cationic starches used in size press reduced COD load in the effluents and increased One Pass Retention. It had been found that when cationic starch used as a surface sizing agent, more starch was retained on or near the surface of the sheet than with conventional oxidized starches. Thus surface strengths and quality were improved. In addition it is possible to maintain the desired level of starch penetration into the fiber net and improve porosity, opacity and brightness. In contrast, in most cases, dusting problems are notably eliminated. Cationic surface sized starch improved black and color ink-jet print quality in terms of feathering and optical density of the print image. These improved properties were believed to be due to a combination of fiber bonding and surface orientation more uniform starch concentration on the paper surface was resulted. Moreover cationic charges in the paper surface lend themselves excellently to fix ink jet ink anionic in nature.