• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1871-1874
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• 2005

The direct write FIB technology has several advantages over contemporary micro-machining technology, including better feature resolution with low lateral scattering and capability of maskless fabrication. Therefore, the application of FIB technology in micro fabrication has become increasingly popular. In recent model of FIB, however the feeding system has been a very coarse resolution of about a few ${\mu}m$. Our research is the development of nano stage of 200mm strokes and 10nm resolutions. Also, this stage should be effectively operating in ultra high vacuum of about $1x10^{-7}$ torr. This paper presents the discussion and results of CAE of the 2 axes stages. we have estimated the stable static and dynamic characteristics for dual servo system. Therefore the 2 axes stages developed and future work are introduced at the end of the paper.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.348-352
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• 2002

a basis such as IT(Information Technology), NT(Nano Technology) and BT(Bio Technology). Recently, NT is applied to various fields that are composed of science, industry, media and semiconductor-micro technology. It has need of IT that is ultra-precision positioning technology with strokes of many hundreds mm and maintenance of nm precision in fields of ultra micro process, ultra precision measurement, photo communication part and photo magnetic memory. This thesis represents optimal design on ultra-precision positioning with single plane X-Y stage and development of artificial control system for adequacy of industrial demand. Also, dynamic simulation on global stage is performed by using ADAMS (Automated Dynamic Analysis of Mechanical System) for the purpose of grasping dynamic characteristic on user designed X-Y global stage. The error between displacements from micro stage and from FEM(Finite Element Method) is 3.53% by verifications of stability on micro stage and control performance. As maximum Von-mises stress on hinge of micro stage is 5.981kg/mm$^2$ that is 1.5% of yield stress, stability on hinge is secured. Preparing previous results, optimal design of micro stage can be possible, and reliance of results with FEM can be secured.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.143-153
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• 2005

J.Y. CHOI,S. J. KIM, E. L. LEE. Change of plantar pressure Distribution of Open Stance during Forehand Strke in Tennis. Korean Journal of Sport Biomechanics, Vol. 15, No. 1, PP. 143-153, 2005. Recently among several tennis techniques forehand stroke has been greatly changed in the aspect of spin, grip and stance. The most fundamental factor among the three factors is the stance which consists of open, square and close stance and it is very important to know the patterns of plantar pressure distribution for the better understanding of forehand stroke. Therefore, the purpose of this study was to investigate the change of plantar pressure distribution in open stance during forehand stroke in tennis. Three high school tennis players were recruited for the study and required to perform forehand stroke five consecutive trials in the condition of open stance. The forehand strokes were filmed with two digital video cameras and measured with pedar system for plantar pressure. The plantar regions under the foot were divided into 3 regions, which were forefoot, midfoot, and rear foot. In conclusion, The plantar pressure of open stance during forehand stroke was distributed more largely to the right foot. The plantar pressure of open stance during forehand stroke was distributed more weight loads on forefoot of right than heel of right

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.593-598
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• 2006

웨어러블 컴퓨팅 환경에서 사용 가능한 키보드는 부담 없이 착용할 수 있어야 하며 충분히 빠른 속도로 문자를 입력할 수 있어야 한다. 또한 일반적인 사용자도 특별한 훈련과정 없이 쉽게 사용할 수 있어야 한다. 상용화된 웨어러블 컴퓨팅용 입력장치는 주로 소형화 QWERTY 키보드인데 공통적으로 키 수를 줄이는 방식을 택하고 있다. 그러나 줄이는 키 수에 대응하여 문자 입력을 위한 키 입력 수(KSPC: Key Strokes per Character)가 증가하기 때문에 입력효율이 저하되고 학습을 위한 요구되는 노력이 또한 증가한다. 그럼에도 불구하고 Halfkeyboard, WristPC keyboard, FrogPad 등 상품화된 키보드는 충분히 작은 사이즈가 아니어서 일상적으로 부담 없이 수용하기에는 물의가 있다. 본 연구는 이런 문제점을 해결하기 위해 키 간격을 줄여 극적으로 키보드를 소형화할 수 있는 원키 키보드라는 개념을 제안하였다. 전통적인 키보드의 경우 하나의 키에 하나의 문자가 할당되는데 반해 원키 키보드는 하나의 키 판 위에 10*5 배열의 QWERTY 키보드 문자배열을 표시하게 하였다. 또한 표시된 문자판에서 어떤 것을 선택하여 눌렀는지 손가락의 위치를 센싱하여 해당 문자를 입력하도록 하였다. 70mm*35mm 크기의 원키 키보드에 대한 실험결과 착용성과 사회적 수용성이 우수하였으며 5 세션의 시도를 통해 평균 18.9WPM 의 입력속도와 교정되지 않은 순수 에러율 0.87%를 기록하였다.

• 한국가스학회:학술대회논문집
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• 2006.11a
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• pp.191-195
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• 2006

Because of the continuous growth of energy consumption and also the tendency to site gas pipeline and power line along the same route, the close proximity of power lines and buried metallic pipelines has become more and more frequent. The lightning strokes collected by an electric substation or power line tower might cause arcing through the soil to an adjacent gas pipeline. This paper gives the outline of the resistance coupling and the standards of distance between gas pipeline and tower ground.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.261-264
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• 2004

This paper presents the design and test of elliptical vibration assisted cutting tool post. It is actuated by two piezoelectric actuators which are connected to the moving part through the elastic hinge with its role of imposing the preliminary pressures. These two actuators are located at right angles so that the resulting tool tip moves like a two-dimensional ellipse. Also, the tool post is activated within the region of linear actuation in order to overcome the distorted elliptical motion. For the precise measurement of the displacement of the tool tip, three-dimensional experimental apparatus was designed and the strokes of the tool post in major and minor axes were measured. The results show that the tool post can produce the variety of vibration locus from a circle with a radius of 5 ${\mu}{\textrm}{m}$ to an ellipse with a major axis, a =10 ${\mu}{\textrm}{m}$, and a minor axis, b =2.5 ${\mu}{\textrm}{m}$

• The Journal of Internal Korean Medicine
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• v.21 no.5
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• pp.765-771
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• 2000

Objectives : To evaluate the pain control effect of combination treatment of Oriental Medicine on patients who suffered from thalamic pain syndrome caused by thalamic stroke. Methods : We reviewed the medical records and brain imaging data of all patients with thalamic stroke from September 1998 to August 2000 who visited to Department of Oriental Internal Medicine, National Medical Center. We evaluated clinical features of thalamic pain syndrome, including incidence, onset interval from stroke, nature, pain distribution, and assessed the pain control effect of combination treatment by Visual Analog Scale(VAS). Results : 64 cases were selected under the inclusion criteria, and 17 patients(26.5%) with thalamic pain syndrome were identified from 64 thalamic strokes. VAS proved combination treatment effective to control pain of thalamic pain syndrome. In 12 cases(70.5%), pain onset was within the first week poststroke. The patients with allodynia were 6(35.3%). In 12 cases(70.5%), the lesion was mainly located in the posterolateral areas of thalamus. Conclusion : We conclude that combination treatment of the Oriental Medicine modalities have pain control effectiveness on thalamic pain syndrome.(t=-5.47, p=0.0001)

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.112-117
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• 2004

In this paper, in order to obtain the detailed information about lightning electromagnetic pulses, the electromagnetic pulses radiated from intracloud discharges were measured, and their characteristics and waveform parameters were analyzed statistically. The electromagnetic pulses produced by intracloud discharges are distinctly different with those by lightning return strokes. The zero-crossing times and the full pulse widths of the large bipolar electromagnetic pulses are gradually decreased as the stroke proceeds. Also, the electromagnetic pulses tend to be bipolar, with narrow and fast leader pulses superimposed on the initial half cycle. The mean numbers of leader pulses superimposed on the initial half cycle were 1.61$\pm$0.74 and 1.75$\pm$0.73 for the positive and negative polarities, respectively.

• Journal of Korean Physical Therapy Science
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• v.6 no.4
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• pp.209-220
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• 1999

This study was conducted in order to determined the risk factors and general characteristics in stroke patients. This study was performed by interviewing a total of 92 hospitalized in Hanil hospital, Chinju and Eulji Medical Collage Hospital, Taejon from January 1, 1998 to February 28, 1999. The results are as follow; 1. Of the types of the strokes, hemorrhagic was 58.8%, ischemic was 41.1%. 2. The family history was appeared to 72.2% of total and did not exercise 64.1% of male and 59.5% of female during weak. 3. The korean peoples as the likes rather Chinese medicine and folk remedy than Wes-ern medicine so late treatment of early stage. 4. Generally, in drinking, smoking, fatness and overeating meat known to affect on stroke both male and female had signification difference. 5. These 75.5% of the subjects was recognizing to necessity of physical therapy.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.1
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• pp.38-50
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• 1994

To improve the efficiency of internal combustion engines, it is necessary to understand mixed air-fuel in-cylinder flow processes accurately at intake and compression strokes. There is experimental and numerical methods to analyse in-cylinder flow process. In numerical method, standard $k-{\varepsilon}$ model with wall function was mostly adopted in in-cylinder flow process. But this type model was not efficiently predicted in the near wall region. Therefore in the present study, low Reynolds number $k-{\varepsilon}$ model was adopted near the cylinder wall and standard $k-{\varepsilon}$ model in other region. Also QUICK scheme was used for convective difference scheme. This study takes axisymmetric reciprocating model engine motored at 200rpm with a centrally located valve, incorporated 60 degree seat angie, and flat piston surface excluding inlet port. Because in-cylinder flow processes are undergoing unsteady and compressible, averaged cylinder pressure and inlet velocity at arbitrary crank angle are determined from thermodynamic analytic method and incylinder states at that crank angle are iteratively determined from the numerical analytic method.