• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.163-170
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• 2002

The quality of a precision product, in general, relies on the accuracy and precision of its manufacturing and inspection process. In many cases, the level of precision in the manufacturing and inspection system is also dependent on the positioning capability of tool with respect to the work piece in the process. Recently the positioning accuracy level has reached to the level of submicron and long range of motion is required. For example, for 1 GDARM lithography, 20nm accuracy and 300mm stroke needs. This paper refers to the lithography stage especially to fine stage. In this study, for long stroke and high accuracy, the dual servo system is proposed. For the coarse actuator, LDM (Linear DC Motor) is used and for fine one VCM is used. In this study, we propose the new structure of VCM for the fine actuator. It is 3 axis precision positioning stage for an aligner system. After we perform the optimal design of the stage to obtain the maximum force, which is related to the acceleration of the stage to accomplish throughput of product. And we controlled this fine stage with TDC. So we obtained 50nm resolution. So later more works will be done to obtain better accuracy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.748-753
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• 2000

Nowadays, many studies and researches in data storage have been carried out and storage capacity is increased. But the limitation of storage capacity is happened for several problems. One of them is spot & pit size in optical and magnetic data storage and another is the resolution of actuators. The problems in spot & pit size is covered by new data storage methods- for example, NFR{Near-Field Recoding) system. But the resolution limit of an actuator doesn't follow up the development of spot & pit size. Because of them, we should improve a resolution of an actuator. Especially, in this paper an actuator is studied and designed for NFR(in using SIL(Solid Immersion Lens) system. It is a dual stage actuator, which consists of a Fine actuator and a Coarse actuator, and should desire 100nm accuracy. But, our actuator system only includes tracking mechanism execpt focusing mechanism which is controlled by slider mechanism used in HDD. Its actuating force generation method is VCM(Voice Coil Motor). The Fine actuator is composed of 4-leaf springs and a bobbin wrapped by coil. The Coarse actuator has Coils and 3-Roller bearings.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.297-300
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• 2022

본 연구는 메타버스의 정보전달 효과를 확인하기 위해 대면 대화 대비 메타버스의 정보전달 효용성을 비교 분석하였다. 대면 대화, 메타버스, 화상회의, 메신저앱 플랫폼을 독립변수로 하여 정보전달 효용성을 측정하였으며 설문조사로 구성된 1차 실험과 사후 행동 관찰을 실시한 2차 실험으로 나누어 실험하였다. 1차 실험에서는 유의미한 차이가 발견되지 않았으나 실험을 마치고 수 일이 지난 후 예고없이 실시한 2차 실험에서는 대면 대화와 화상회의가 높은 수치를 기록한 데에 반해 메타버스와 메신저앱은 유의미하게 낮은 수치를 기록하였다. 메타버스가 코로나시대에 사회적 공간제약을 극복하는 대체재로 쓰였으나 자유로운 대면 활동이 다시 가능해진다면 대면대화 대비 정보전달 효용성이 떨어질 수 있으므로 메타버스의 장단점을 충분히 이해하고 활용해야 할 것이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.155-160
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• 2003

This paper presents a multiple face detector based on a robust pupil detection technique. The pupil detector uses active illumination that exploits the retro-reflectivity property of eyes to facilitate detection. The detection range of this method is appropriate for interactive desktop and kiosk applications. Once the location of the pupil candidates are computed, the candidates are filtered and grouped into pairs that correspond to faces using heuristic rules. To demonstrate the robustness of the face detection technique, a dual mode face tracker was developed, which is initialized with the most salient detected face. Recursive estimators are used to guarantee the stability of the process and combine the measurements from the multi-face detector and a feature correlation tracker. The estimated position of the face is used to control a pan-tilt servo mechanism in real-time, that moves the camera to keep the tracked face always centered in the image.

• Journal of Acupuncture Research
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• v.21 no.6
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• pp.209-219
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• 2004

Objective : This study was designed to compare acupuncture sensation index among three different acupuncture devices. Methods : A, B and C acupuncture devices were inserted into Quchi(LI 11) of the subjects. After 5 minutes the subjects completed a questionnaire rating the intensity of 21 kinds of acupuncture sensation; hurting, penetrating, sharp, aching, intense, spreading, radiating, tingling, pricking, stinging, pulling, heavy, dull, numb, electric, shocking, hot, burning, cool, pulsing, and throbbing. We compared subjective evaluations of acupuncture sensation among the groups. Results : The acupuncture sensation index when administrated among three different acupuncture devices(A, B and C) was not significantly different. The acupuncture sensation of B acupuncture devices showed significant difference than A or C in Spreading, Dull, Numb item. But, the other items of acupuncture sensation were not significantly different among three acupuncture devices. Conclusions : We found that acupuncture sensation index when administrated among three different acupuncture devices. Further study is needed to know different acupuncture sensation among acupuncture devices.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1823-1830
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• 2003

This paper presents a multiple face detector based on a robust pupil detection technique. The pupil detector uses active illumination that exploits the retro­reflectivity property of eyes to facilitate detection. The detection range of this method is appropriate for interactive desktop and kiosk applications. Once the location of the pupil candidates are computed, the candidates are filtered and grouped into pairs that correspond to faces using heuristic rules. To demonstrate the robustness of the face detection technique, a dual mode face tracker was developed, which is initialized with the most salient detected face. Recursive estimators are used to guarantee the stability of the process and combine the measurements from the multi­face detector and a feature correlation tracker. The estimated position of the face is used to control a pan­tilt servo mechanism in real­time, that moves the camera to keep the tracked face always centered in the image.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1883-1886
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• 2005

In this paper, a decoupled dual servo (DDS) stage for ultra-precision scanning system with large working range is introduced. In general, dual servo systems consist of a fine stage for short range and a coarse stage for long range. The proposed DDS also consists of a $XY\theta$ fine stage for handling and carrying workpieces and one axis coarse stage. Its coarse stage consists of air bearing guide system and a coreless linear motor with force ripple. The fine has four voice coil motors(VCM) as its actuator. According to a VCM's nature, there are no mechanical connections between coils and magnetic circuits. Moreover, VCM doesn't have force ripples due to imperfections of commutation components of linear motor systems - currents and flux densities. However, due to the VCM's mechanical constraints the working range of the fine is about $25mm^2$. To break that hurdle, the coarse stage with linear motors is used to move the fine about 500mm. Because of the above reasons, the proposed DDS can achieve higher precision scanning than other stages with only one servo. With MATLAB's Sequential Quadratic Programming (SQP), the VCMs are optimally designed for the highest force under conditions and constraints such as thermal dissipations due to its coil, its size, and so on. And for their movements without any frictions, guide systems of the DDS are composed of air bearings. To get precisely their positions, a linear scale with 5nm resolution are used for the coarse stage's motion and three plane mirror laser interferometers with 5nm for the fine's $XY\theta$ motions. With them, on scanning the two stages have same trajectories. The control algorithm is named Parallel method. The embodied ultra-precision scanning system has sub 100nm following error and in-positioning stability.

• Microbiology and Biotechnology Letters
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• v.12 no.4
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• pp.299-304
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• 1984

Saprophytic microorganisms of onion bulbs in Korea were confirmed, and effects of temperature, humidity and fumigation by Tetrachloro isophthalonitrile on Botrytis-rot were investigated in order to decrease storage loss of onions. Dominant saprophytes were Botrytis, Penicillium and Fusarium as molds which were all pathogens, and Erwinia and Pseudomonas as bacteria of which Pseudomonas was a non-pathogen. Botrytis-rot was most effectively suppressed by temperature. At $0^{\circ}C$, the incubation days at which 50% area of one onion leaf-fragment (2.5$\times$2.5cm) inoculated by Botrytis was rotten were 26.2 days and the rotting was delayed more by 21.8 days than at $25^{\circ}C$. For humidity, the effect was pretty insignificant in contrast with temperature effect. At RH 70% and $0^{\circ}C$, the incubation days at which 50% area of one onion leaf-fragment was rotten were 28.0 days and the rotting was delayed more by 1.8 days than at RH9o% and $0^{\circ}C$. By fumigation, the rotting was delayed by 3.8 days at RH 70% and $0^{\circ}C$. In case of slightly infected samples, temperature effect was reduced and the effects of humidity and fumigation were ignored, which implies that storage samples should be healthy.

• Korean journal of applied entomology
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• v.49 no.4
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• pp.357-362
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• 2010

Soybean seed injury was analyzed in the experiments in which the bean bug, Riptortus pedestris(Hemiptera: Alydidae), was released into screen-caged pots containing full seed stage(R6) of soybean. When the different stages of insects, from the 3rd instar nymphs to adults, were released into pots during 8 days in soybean R6 stage, soybean seeds with injury marks (B-type seeds) increased. The weight reduction ratio in B-type seeds was highest in the injury by the 5th instar nymphs, while the daily-produced number ratio of B-type seeds was small in the treatment. In the injury by the different number of adult released into pots, 4, 8, 16 adults caused a significant increase of B-type seeds, while 16 adults caused the significant increase of the deformed (C-type) seeds. In the injury by the different release period of adults, the total number of pods was not significantly different among treatments, while the total seed number harvested was significantly small in the release for 48 days. The release for 8 and 16 days caused a significant increase of B-type seeds, while the release for 48 days caused the increase of C-type seeds. The results indicated that injury of soybean R6 stage by the bean bug produced soybean seeds with distinct injury marks at relatively low density and during short term attack period, while it produced deformed seeds at high density and during long attack period.

• Journal of Yeungnam Medical Science
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• v.7 no.2
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• pp.39-48
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• 1990

Congenital duodenal obstruction in the newborn infant may be due to a variety of causes. Duodenal obstruction often presents with bilious vomiting and upper abdominal distention. Diagnosis is usually established on plain x-ray of the abdomen by the classic finding of the double-bubble. In the period July 1986 to June 1990, 16 patients with congenital duodenal obstruction were operated and the following results were obtained. 1. Sixteen patients were comprised of 11 males and 5 females, the ratio of male and female was 2.2:1. 2. Thirteen patients(81%) had been admitted to our hospital during one month of life. 3. Congenital duodenal obstruction was in 16 cases; malrotation in eight(50%), annular pancreas in six(38%), type 1 atresia in one(6%), and wind-sock anomaly in one(6%). 4. There were two premature patients and six patients of small for gestational age. 5. Overall, bilious vomiting, occurring in three fourths, was the single most frequent presenting complaint. 6. Polyhydramnios occurred in two of the patients. 7. Diagnosis was possible with clinical symptom and simple abdomen. 8. The operative procedures performed were ; duodenoduodenostomy in five, duodenojejunostomy in two, excision of wind-sock membrane in one, and Ladd's procedure in eight. 9. A total of ten asociated congenital anomalies were found in six patients. 10. Postoperative complications occurred in five cases(31%).