• 디지털산업정보학회논문지
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• 제5권2호
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• pp.29-37
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• 2009

Recently, the structure of simulation environment is important issue in all fields. In case of the training for operating the machines which are costly such as airplanes or spaceships, simulators could be helpful for decreasing the costs and training effects by simulating real situation. When we get the driving license, too many peoples are waiting for their turns because of limited cars and testing spaces in Korea. To solve this problem, we've designed and developed the basic design for the simulators. We suggested the Computer 3D Simulation Model for practice of a drives's license. The concept of this simulator was from a 3D Racing-game which suit for driving exercise. We provide users with handle-controlled simulation setting in order that users feel reality as if they drive really through this simulator. We also use 'force-feedback' system which give handle vibration in case users collide against obstacles or exceed the line since users can absorb the simulation program and feel the sense for the real. This paper is the study about modeling the driving exercise model made use of 'computer 3D simulation', and producing and utilizing the simulator through this modeling.

• 로봇학회논문지
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• 제8권3호
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• pp.156-163
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• 2013

This paper describes a flexible visuo-haptic display module. We have developed a flexible electro-active polymer (EAP) actuator and a thin flexible visual display with $3{\times}3$ array configuration via polymer technology. The flexible actuator consists of nine EAP cells vertically moving in response to change in their thickness. The flexible display uses polymer based optical waveguide allowing light to scatter only at specific area. The display film is transparent and identically designed to the array pattern to fit for the arrangement of actuator cells. A pressure sensor is installed under the integrated module. The performance of the actuator is proved to be sufficient for satisfying perceivable range of human touch sense. The integrated system can provide interactive haptic feedback such as key pressing, contact vibration sensations, and etc. in accordance with user input.

• 대한전자공학회논문지
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• 제15권5호
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• pp.19-24
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• 1978

기계적 진동 주파수와 파형, 2점식별 thresho1d 치, 접촉자의 크기에 대한 피체 진동촉각의 기능적 성질을 심리물리실험에 의해 연구했다. 이의 실험 결과를 기초로 하여 압전 진동소자를 이용한 진동촉각 자극장치를 제작하여 한글을 인식하기 위한 맹인용 시각보조 장치로써 제안했다. 촉각출력상은 200 Hz의 구형파에 의해 진동하는 8열×l행의 소형 진동자열에 의해 집게 손가락에 표시했다. NOVA미니컴퓨터의 제어에 의해 한글 자모 24자중 하나를 택하여 진동자열의 8점에 왼쪽에서 오른쪽으로 제시하도록 했다. 한글 식별률실험은 설계한 실험시스템에 의해 학습효과없이 행했으며 측정된 평균식별률은 90%였다.

• Journal of Astronomy and Space Sciences
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• 제15권1호
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• pp.209-220
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• 1998

The stability problem of steady motion of a rigid body with multi-elastic appendages and multi-liquid-filled cavities, in the presence of no external forces or torque, is considered in this paper. The flexible appendages are modeled as the clamped -free-free-free rectangular plates, or/and as the discrete mass- spring sub-system. The motion of liquid in every single ellipsoidal cavity is modeled as the uniform vortex motion with a finite number of degrees of freedom. Assuming that stationary holonomic constraints imposed on the body allow its rotation about a spatially fixed axis, the equation of motion for such a systematic configuration can be very complex. It consists of a set of ordinary differential equations for the motion of the rigid body, the uniform rotation of the contained liquids, the motion of discrete elastic parts, and a set of partial differential equations for the elastic appendages supplemented by appropriate initial and boundary conditions. In addition, for such a hybrid system, under suitable assumptions, their equations of motion have four types of first integrals, i.e., energy and area, Helmholtz' constancy of liquid - vortexes, and the constant of the Poisson equation of motion. Chetaev's effective method for constructing Liapunov functions in the form of a set of first integrals of the equations of the perturbed motion is employed to investigate the sufficient stability conditions of steady motions of the complete system in the sense of Liapunov, i.e., with respect to the variables determining the motion of the solid body and to some quantities which define integrally the motion of flexible appendages. These sufficient conditions take into account the vortexes of the contained liquids, the vibration of the flexible components, and coupling among the liquid-elasticity solid.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제12권6호
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• pp.275-284
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• 2023

가상 현실 시뮬레이션은 다양한 분야에서의 교육과 훈련에 활용이 되며, 특히 최근에는 의료 분야에서 많이 사용되고 있다. 교육/훈련용 시뮬레이터는 의사가 실제 수술 도구를 이용하여 실제 환자에 대해 처치를 하는 것과 같은 느낌이 나게 하는 촉감/역감 생성 및 영상/음향 출력 하드웨어와 여기에 실감 나는 영상과 촉감을 생성해주는 소프트웨어로 이루어진다. 기존의 시뮬레이터들은 수술 시에 사용되는 다양한 수술 도구들을 모사하기 위해 다양한 형태의 하드웨어들을 사용해야 하므로 복잡하고 비용이 많이 소요되는 문제가 있다. 이 논문에서는 포스 피드백 장치와 변형 가능한 햅틱 컨트롤러를 이용한 치과 수술 시뮬레이션 시스템을 제안한다. 햅틱 하드웨어들은 수술 도구와 수술 부위의 충돌 여부를 파악하고 그에 따른 저항감과 진동감을 제공한다. 특히 길이 변화, 굽힘과 같은 변형이 가능한 햅틱 컨트롤러는 여러 수술 도구들의 형태에 따라 느껴지는 다양한 감각을 표현할 수 있다. 사용자가 햅틱 피드백 장치를 조작하면 햅틱 피드백 장치의 움직임이나 버튼 클릭 등의 이벤트가 시뮬레이션 시스템에 전달되어 치과용 수술 도구와 구강 내부 모델들 사이의 상호작용이 발생하고 이에 따른 햅틱 피드백이 햅틱 피드백 장치로 전달된다. 이러한 기반 기술들을 활용하여 정교한 3차원 모델로 표현된 가상 환경에서 대표적인 치과 수술기법인 매복 사랑니 발치 수술의 현실적인 훈련 경험을 제공한다.

• 실천공학교육논문지
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• 제5권2호
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• pp.169-176
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• 2013

최근 시뮬레이션 환경 구축은 모든 분야에 걸쳐서 중요한 이슈로 떠오르고 있다. 특히 비행기나 우주선과 같은 한 번 작동 하는데 많은 비용이 드는 기기의 훈련일 경우, 실제 기기와 같은 환경을 시뮬레이터로 구축하여 놓음으로써 막대한 비용의 절감과 함께, 실전에서와 같은 훈련 효과를 가져올 수가 있다. 이에 우리는 일반 운전학원에서 운전 면허 획득을 위한 연습시 차량의 부족과 많은 인원으로 인해 대기 시간이 많이 지연되고 있음에 착안하여, 운전 연습에 맞는 시뮬레이터를 개발한다. 운전 연습에 적합한 시뮬레이터인 3D 레이싱 게임에 착안하여, 운전 면허 실습을 위한 컴퓨터 3D시뮬레이션 모델을 제안하고, 이를 사용하여 사람들이 실제 운행을 하는 것처럼 핸들을 조작하는 시뮬레이션 환경을 제공한다. 본 논문은 컴퓨터 3D 시뮬레이션을 활용하여 운전 연습 모델을 모델링하고, 이 모델링을 사용하여 시뮬레이터를 제작하여 활용하는 것에 관한 연구이다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.135-139
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• 2001

This paper describes a string resonator that is used for the interrogation system of a Fiber Bragg Grating(FBG) strain sensor. The strain on the fiber piece is calculated from the measured frequency based on that the natural frequency of a string is a function of the applied absolute strain. Existing research considered a fiber as a string, but a fiber is not a string in the strict sense due to its bending stiffness, thus the fiber should be modeled as a beam accompanied with an axial force. In the vibration modeling, the relationship between the strain and the natural frequency is derived, and then the resonance condition is described in terms of both the phase and the mode shape for sustaining resonant motion. Several experiments verify the effectiveness of the proposed model of the fiber. The performance of the string resonator is analyzed by measuring the frequency change according to the applied strains in the dynamic range of 1100$\mu\varepsilon$ referred to the displacement from capacitance sensor. From the experimental results, the implemented string resonator provides the accuracy of $\pm$3$\mu\varepsilon$, the quasi-static resolution of ~0.1$\mu\varepsilon$(rms) which amount to be $\pm$0.17$\mu\textrm{m}$ and ~6nm respectively, in case of fiber length of 56mm. For a dynamic strain, it can provide the accuracy of ~3$\mu\varepsilon$ until the frequency comes to 8Hz. As a consequence, the string resonator proposed for FBG sensor provides the high accuracy and the high resolution in strain measurement, and also it is expecting to be used, for the application, to not only strain but also displacement measuring device.

• 대한소아치과학회지
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• 제24권4호
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• pp.763-770
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• 1997

The air abrasive technique is a non-mechanical method by which teeth are treated before restoration and stains and calculi are removed from tooth surfaces using the kinetic energy of small particles. The air abrasive technique in dentistry was first introduced in the 1950's with as instrument called 'Airdent'. But, as the main restorative materials of the period were amalgam and gold, and the instrument's inability to control the flow of particles caused the particles to be spread throughout the clinics, widespread use was not possible. In the 1990's, as these techincal problems were solved and more interest in new restorative materials rose in an effort to preserve sound tooth structure, new developements took place in instruments related to the air abrasive technique. The air abrasive technique produces less pressure, vibration and heat that might cause patient discomfort and facilitates the preservation of sound tooth structure. It also reduces the need for anesthesia and is less harmful to the pulp. Other advantages include increase in dentin bonding strength of composite resin, lower possibility of saliva contamination and maintenance of a dry field. But there is not direct contact between the nozzle and the tooth, the operator cannot use his or her tactile sense and must rely solely upon visual input. Other disadvantages are: the tooth preparation depends on the operator's ability; alpha-alumina particles, after bouncing off the tooth surface, cause damage to dental mirrors; the equipment is expensive and takes up a certain amount of space in the clinic. The author conducted case report using the air abrasive technique on patient visiting the Department of Pediatric Dentistry at Seoul National University Dental Hospital and arrived at the following conclusions. 1. The tooth preparation capability of different air abrasive devices varied widely among manufacturers. 2. It was more effective in treating early caries lesions and stains compared to lesions where caries had already progressed to produce soft dentin. 3. The cold stream and noise caused by the evacuation system was a major cause of discomfort to pediatric patients. 4. As there is no direct contact with tooth surface when using the air abrasive technique for tooth preparation, considerable experience and skill is required for proper tooth preparation.