• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.289-290
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• 2006

In general, atomic force microscope (AFM) used for metrological purpose has measuring range less than a few hundred micrometers. We design and fabricate an AFM with long measuring range of $200mm{\times}200mm$ in X and Y axes. The whole stage system is composed of surface plate, global stage, microstage. By combining global stage and microstage, the fine and long movement can be provided. We measure the position of the stage and angular motions of the stage by laser interferometer. A piezoresistive type cantilever is used for compact and long term stability and a flexure structure with PZT and capacitive sensor is used for Z axis feedback control. Since the system is composed of various actuators and sensors, a real time control program is required for the implementation of AFM. Therefore, in this work, we designed a multi-axis control program using a FPGA module, which has various functions such as interferometer signal converting, PID control and data acquisition with triggering. The control program achieves a loop rate more than 500 kHz and will be applied for the measurement of grating pitch and step height.

• 한국운동역학회지
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• 제15권4호
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• pp.105-115
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• 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 closed stance. The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle according to open, close, and square stance patterns during forehand stroke in tennis. For the movement analysis three dimensional cinematographical method(APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVIEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and racket head angle were defined. In conclusion, the first hypothesis, "In three dimensional maximum linear velocity of racket head would be significant difference among the stance patterns during forehand stroke in tennis" was rejected. The second hypothesis, "In three dimensional anatomical angular displacement of trunk would be significant difference among the stance patterns during forehand stroke in tennis" was rejected and the result showed that the internal-external rotation showed most important role among the three dimensional anatomical angular displacement of trunk The third hypothesis, "In three dimensional anatomical angular displacement of upperlimb would be significant difference among the stance patterns during forehand stroke in tennis" was rejected and the result showed that The three dimensional anatomical angular displacement of shoulder joint showed most important role in forehand stroke. Flexion-extension and internal-external rotation the open stance showed the largest angular displacement and is follwed by square stance and closed stance. The fourth hypothesis, "In three dimensional anatomical angular velocity of upperlimb would be significant difference among the stance patterns during forehand stroke in tennis" was rejected and the result showed that X-axis angular velocity and Z-axis angular velocity the square stance showed the largest angular velocity of the trunk and X-axis angular velocity and Y-axis angular velocity the closed stance showed the largest angular velocity of the shoulder joint.

• Imaging Science in Dentistry
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• 제32권3호
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• pp.159-165
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• 2002

Purpose: The aim of this study was to introduce a method of obtaining the oscillation graphs of the dental x-ray tube heads relative to time using an accelerometer. Materials and Methods: An Accelerometer, Piezotron type 8704B25 (Kistler Instrument Co., Amherst, NY, USA) was utilized to measure the horizontal oscillation of the x-ray tube head immediately after positioning the tube head for an intraoral radiograph. The signal from the sensor was transferred to a dynamic signal analyzer, which displayed the magnitude of the acceleration on the Y-axis and time lapse on the X -axis. The horizontal oscillation of the tube head was measured relative to time, and the settling time was also determined on the basis of the acceleration graphs for 6 wall type, 5 floor-fixed type, and 4 mobile type dental x-ray machines. Results : The oscillation graphs showed that tube head movement decreased rapidly over time. The settling time varied with x-ray machine types. Wall-type x-ray machines had a settling time of up to 6 seconds, 5 seconds for fixed floor-types, and 1 I seconds for the mobile-types. Conclusion: Using an accelerometer, we obtained the oscillation graphs of the dental x-ray tube head relative to time. The oscillation graph with time can guide the operator to decide upon the optimum exposure moment after x-ray tube head positioning for better radiographic resolution.

• 한국운동역학회지
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• 제21권2호
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• pp.215-222
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• 2011

The purpose of this study was to analyze the effects of the use of the lower extremity supporter to ground reaction force(GRF) & EMG in women. Five women participated in the experiment conducted in the study(age: $46.7{\pm}3.5$ yrs, weight: $52.3{\pm}2.2$ kg, lower extremity height: $74.1{\pm}0.9$ cm, knee height: $40.7{\pm}1.4$ cm). The Ground reaction force was measured by AMTI ORG-6 and the Muscle activity of the lower extremity was measured by an 8-channel surface EMG system(Noraxon Myoresearch, USA, 1000Hz). We statistically compared muscle activity and ground reaction force with and without the lower-extremity supporter by one-way repeated ANOVA. The results were as follows. First, the use of the lower extremity supporter affects the ground reaction force along the anterior-posterior axis(Y). Second, the vertical(Z-axis) reaction force on the upper part of the lower extremity supporter increase because of the difference between the interval of vertical movement. Third, the muscle activity of the lateral gastrocnemius and rectus femoris was higher in the upper part of the lower extremity supporter. Further research for example, on a comparative analysis of joint moments, the effects of direct stressor on joints. and the relationship between muscle activity and joint movement, is necessary for a better understanding of the effects of the lower-extremity supporter.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권1호
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• pp.23-27
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• 2010

The purpose of this study was to evaluate the reliability of 6-axis model surgery simulator (6AMSS) for orthognathic surgery. A rectangular parallelepiped plastic block was assembled to model-mounting plate of 6AMSS. Left-right (X), anterior-posterior (Y), up-down (Z) translation and pitching (${\phi}X$), rolling (${\phi}Y$) and yawing (${\phi}Z$) rotation was planned and performed using 6AMSS. The actual translation and rotation were measured with dial gauge and precisional protractor, respectively. Comparison between the planned and actual movements of plastic block for each variable were made using paired t- test. Statistical analysis for X, Y, Z, ${\phi}X$, ${\phi}Y$ and ${\phi}Z$ movement have shown no significant differences between planned and actual movement (P > 0.05). This indicate that model surgery performed with the aid of the 6AMSS is accurate in 3D translation and rotation. The 6AMSS is practically useful for accurate fabrication of surgical splint for orthognathic surgery.

• International Journal of Precision Engineering and Manufacturing
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• 제6권1호
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• pp.51-58
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• 2005

The development of the high-efficiency machine-tools equipment and new cutting tool materials with high hardness, heat- and wear-resistance has opened the way to application of high-speed cutting process. The basic argument of using of high-speed cutting processes is the reduction of time and the respective increase of machining productivity. In this sense, the spindle units may be regarded as one of the most important units, directly affecting many parameters of high-speed machining efficiency. One of the possible types of spindle units for high-speed cutting is the air-bearing type. In this paper, we propose the mathematical model of the dynamic behavior of the air-bearing spindle. To provide the high-level of speed capacity and spindle rotation accuracy we need the adequate model of "spindle-bearings" system. This model should consider characteristics of the interactions between system components and environment. To find the working characteristics of spindle unit we should derive the equations of spindle axis movement under the affecting factors, and solve these equations together with equations which describe the behavior of lubricant layer in bearing (bearing stiffness equations). In this paper, the three influence coefficients are introduced, which describe the center of spindle mass displacement, angle of shaft rotation around the axes under the unit force application and that under the unit torque application. These coefficients are operated in the system of differential equations, which describes the spindle axis spatial movement. This system is solved by Runge-Kutta method. Obtained trajectories and amplitude-frequency characteristics were then compared to experimental ones. The analysis shows good agreement between theoretical and experimental results, which confirms that the proposed model of air-bearing spindle is correctis correct

• 한국콘텐츠학회논문지
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• 제17권9호
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• pp.281-291
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• 2017

가상공간의 발달로 인해 비즈니스 환경의 변화도 가속화되고 있다. 이러한 환경에서의 커뮤니케이션은 의미전달 뿐 아니라 감성을 교류하는 감성 커뮤니케이션을 목표로 하고 있다. 그러나 사용자가 필요로 하는 감성에 관한 연구는 부족하다. 본 연구의 목적은 비즈니스 시나리오 기반으로 감성 어휘 모델링을 도출한 후, 해당 감성의 시선 요소를 분석하는 것이다. 이를 위해 417개의 관련 감성 어휘를 수집하여 적합성 검증 후 16개의 대표 어휘를 도출하였고, 다차원척도분석을 통해 2차원 공간에 맵핑하였다. 그 후, FGD를 통해 X축은 협력, 경쟁, Y축은 낮은 몰입, 높은 몰입으로 차원을 정의하였다. 52명의 피험자를 대상으로 해당 감성을 유발하는 자극을 제시하였고 시선 움직임 데이터를 수집하였다. 분석 프로그램을 통해 상대방의 얼굴, 오른쪽 눈, 왼쪽 눈, 코, 입을 관심영역으로 설정한 후, 평균 시간, 비율, 고정점, 다시 돌아오는 횟수의 데이터를 추출하였다. 독립 t-검정 결과, 협력일 때는 경쟁보다 얼굴, 눈, 코 영역에서 시선 요소가 증가하였고, 낮은 집중의 경우 높은 집중보다 오른쪽 얼굴, 코 영역에서 시선요소가 증가한 것을 확인하였다. 이는 가상공간에서의 비즈니스 환경에서 필요한 감성을 평가하는 데 기초 연구로써 활용가능 할 것으로 기대된다.

• 한국콘텐츠학회논문지
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• 제12권5호
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• pp.303-310
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• 2012

방사선 치료에 있어서 정확한 환자 포지셔닝과 셋업은 치료의 성패를 좌우할 수 있는 중요한 인자이다. 기존의 방사선 치료실내에 장착된 3-laser system을 이용한 셋업에서, 최근에는 체표면 윤곽 스캐닝 시스템(C-Rad system)의 사용이 시도되고 있다. 체표면 윤곽 스캐닝 시스템의 유용성을 평가하기 위하여 C-Rad system과 3-laser system을 이용한 셋업 오차의 정확도를 비교, 평가함으로써 임상에서의 유용성을 확인하고자 하였다. 인체부위는 내부적인 움직임이 없고, 고정용구의 적용이 간편한 두경부로 한정하였으며, Alderson Rando anthropomorphic phantom과 두경부에 병변이 있는 방사선 치료 환자 10명을 대상으로 하였다. Phantom을 대상으로 한 C-RAD system의 셋업 에러 평균과 표준편차는 X축 $0.55{\pm}0.51mm$, Y축 $-0.2{\pm}0.523mm$, Z축 $-0.85{\pm}0.587mm$로 나타났으며, 환자를 대상으로 한 실험에서는 X축 $-0.05{\pm}0.621mm$, Y축 $0.075{\pm}0.755mm$, Z축 $-1.025{\pm}0.617mm$로 산출되어, 전반적으로 3-laser system에 비해 셋업의 정확도가 우수하였으나, Z축의 에러 발생률은 C-RAD system이 약간 높게 나타났다. 체표면 윤곽 스캐닝 시스템은 두경부의 방사선 치료 시에 정확한 포지셔닝을 유도함으로써 셋업오차를 최소화 시키는데 기여할 것으로 사료된다.F

• 한국조경학회지
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• 제34권3호
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• pp.32-40
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• 2006

We investigated space establishment and land use of children's parks by studying movement of users in and out of the parks with a questionnaire survey, video and analysis, and then analyzed the characteristics of how the facilities and the space of the parte are used. The results are as follows. First, when considering the character of the facilities of children's parks, entertainment facilities should receive priority followed by those for relaxation and those for convenience. When considering the position of facilities in the parks, because activity spaces may have similar functions to multi-purpose paved spaces, common use of these two spaces should be considered. Entrances and lines of movement should be kept in mind. Second, when considering the surrounding land uses, in case a play facility at a large-sized complex or an elementary school is adjacent, the exercise facilities may be more important, followed by play and rest facilities. In case there is a broad path around the parte, the way in which movement occurs into the central axis should be considered so that the other side of the broad way is not included in the children's play space. Third, proper control of roads adjacent to the parse is needed to protect children from danger.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.661-664
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• 2002

A control of the body posture and movement is maintained by the vestibular system, vision, and proprioceptors. Afferent signals from those receptors are transmitted to the vestibular nuclear complex, and the efferent signals from the vestibular nuclear complex control the eye movement. The postural disturbance caused by loss of the vestibular function results in nausea, vomiting, vertigo and loss of craving for life. The purpose of this study is to develop a off-vertical rotatory system for evaluating the function of semicircular canals and otolith organs, selectively, and visual stimulation system for stimulation with horizontal, vertical and 3D patterns. The Off-vertical axis rotator which stimulates semicircular canals and otolith organs selectively is composed of a comportable chair, a DC servo-motor with reducer and a tilting table controlled by PMSM. And a double feedback loop system containing a velocity feedback loop and a position feedback loop is applied to the servo controlled rotatory chair system. Horizontal, vertical, and 3D patterns of the visual stimulation for applying head mounted display are developed. And wireless portable systems for optokinetic stimulation and recording system of the eye movement is also constructed. The Gain, phase, and symmetry is obtained from analysis of the eye movement induced by vestibular and visual stimulation. Detailed data were described.