• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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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.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.5
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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.

• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.125-134
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• 2020

In this study, Q methodology was applied to investigate the subjective evaluation of department jumpers and characteristics of each type of recognition for college students. As a result of analyzing, they were classified into three types. Type 1 was recognized that the department jumper plays a role of giving a sense of belonging to the department and promoting the department. In addition, it was analyzed that wearing a department jumper would be cautious, but the activities were comfortable and people around me gave good evaluations and thought it had the effect of enhancing my confidence. In the case of type 2, the department jumper was satisfied because it was an easy-to-work and non-fashionable design, and was always worn when going to university. Type 3 was a type that gives a sense of belonging when wearing the department jumper, and that it was good for the department jumper to follow the fashion. It is thought that a department jumper with a good fit should be developed by reflecting the physical characteristics, showing the image or symbolism, so that the department jumper of college students can function as a uniform.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.3
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• pp.99-105
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• 2011

In this paper, we proposed a method for estimating an accurate gamut based on segment maxima method. According to the number of segments in the segment maxima, a local concavity is generated in the vicinity of lightness axis or a gamut is reduced in high chroma region. It induces artifacts or deterioration of the image quality. To remove these artifacts, the number of segment is determined according to the number of samples. and a local concavity is modified by extending a detected concave point to the line connecting two adjacent boundary points. Experimental results show that the contours in a uniform color region and speckle artifacts from the conventional segment maxima algorithm are removed.

• Journal of the Korean housing association
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• v.18 no.1
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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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• v.7 no.1
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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.

• Fashion & Textile Research Journal
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• v.5 no.5
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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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• v.44 no.1
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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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• v.14 no.3
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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.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.2
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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.