• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2001년도 추계학술발표논문집
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• pp.260-264
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• 2001

This paper presents virtual reality using 6-DOF Haptic interface. It is proposed reappearance of force using 6-DOF Haptic device that was designed by previous studies and 3D image considered time delay. The performance of conventional control is excellent in the case of the exactly known dynamic model of the robot, but degrades seriously as the uncertainty of the model increases. The virtual reality using 6-DOF Haptic interface is presented here to overcome such that, and verified through the experiment.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2007년도 추계학술 발표회
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• pp.100-105
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• 2007

• 센서학회지
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• 제8권4호
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• pp.298-307
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• 1999

This paper describes the application of the coupled FE-BEM (finite element-boundary element method) for the numerical harmonic analysis of the linear dynamic behaviour of a magnetostrictive Terfenol-D rod in water. The magnetostrictive rod is three-dimensionally simulated to transduce applied electric current in a helical coil around the rod to mechanical displacement. The theoretical derivation of the magnetostrictive matrix equation is described in detail. The steady-state resonance response of the displacement is shown. In addition, the directivity pattern and the radiation impedance are also shown.

• 소음진동
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• 제10권1호
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• pp.117-122
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• 2000

The dynamics of train has recently been analysed in many cases and very complex nonlinear creep theories have been developed by many engineers. But much calculation time is spent and latest complex creep theories cannot be adapted in train analysis. In this study efficient and fast train analysis method was suggested. Many of degree of freedom were reduced in multi-vehicle system using equivalent system and fast calculation time was achieved. And the accuracy of equivalent system method was proved by linear and nonlinear dynamic analysis.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권3호
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• pp.270-277
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• 2012

This paper presents a new DAC design strategy to achieve a wideband dynamic linearity by increasing the bandwidth of the output impedance. In order to reduce the dominant parasitic capacitance of the conventional matrix structure, all the cells associated with a unit current source and its control are stacked in a single column very closely (stacked unit cell structure). To further reduce the parasitic capacitance, the size of the unit current source is considerably reduced at the sacrifice of matching yield. The degraded matching of the current sources is compensated for by a self-calibration. A prototype 6-bit 3.3-GS/s current-steering full binary DAC was fabricated in a 1P9M 90 nm CMOS process. The DAC shows an SFDR of 36.4 dB at 3.3 GS/s Nyquist input signal. The active area of the DAC occupies only $0.0546mm^2$ (0.21 mm ${\times}$ 0.26 mm).

• 한국수소및신에너지학회논문집
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• 제8권1호
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• pp.31-41
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• 1997

In order to investigate the mechanism of electrochemical hydrogenation reaction on Zr-based Laves phase hydrogen storage alloy electrodes, electrochemical charge/discharge characteristics, potentiostatic/dynamic polarizations and electrocehmical impedance spectroscopy(EIS) of Zr-Ti-Mn-Ni and Zr-Ti-Mn-Ni-M(M=Fe, Co, Al) alloys were examined. Electrochemical discharge capacities of the alloys were quite different with gas charge capacities. Therefore, it was considered that discharge capacities of the alloys depend on electrochemical kinetic factors rather then thermodynamic ones. Discharge efficiencies were increased linearly with exchange current densities. The results of potentiostatic/dynamic polarization measurements showed that electrochemical charge and discharge reaction of Zr-based Laves phase hydrogen storage alloys is controlled by charge transfer process at the electrode surface. The EIS measurements also confirmed this result.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.45.4-45
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• 2002

In EIT, an array of disjoint electrodes is attached on the boundary of the object and a set of small alternating electrical currents is injected into the object through these electrodes, and then the corresponding set of voltages is measured on the same array of the electrodes. The objective in EIT is to estimate the resistivity distribution inside the object based on the set of measured voltages and injected currents. In this paper, we proposed a new dynamic EIT reconstruction scheme based on the interacting multiple model (IMM) algorithm. The main contribution of the proposed scheme is that multiple models are employed for the state evolution to get around the modeling uncertainty. Extensi...

• 한국정밀공학회지
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• 제12권2호
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• pp.69-78
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• 1995

Nonlinear analysis methods are developed which will enable the reliable prediction of the dynamic behavior of the space shuttle main engine(SSME) turbopumps in the presence of bearing clearances and other local nonlinearities. A computationally efficient convolution method, based on discretized Duhamel and transition matrix integral formulations, is developed for the transient analysis. In the formulation, the coupling forces due to the onlinearities are treated as external forces acting on the coupled subsystems. Iteration is utilized to determine their magnitudes at each time increament. The method is applied to a nonlinear generic model of the high pressure oxygen turthods, the convolution approach proved to be more accurate and highly more efficient. For determining the nonlinear, steady-state periodic responses, an incremental harmonic balance(IHB) method was also developed. The method was successfully used to determine dominantly harmonic and subharmonic(subsynchronous) responses of the HPOTP generic model with bearing clearances. A reduction method similar to the impedance formulation utilized with linear systems is used to reduce the housing-totor models to their coordinates at the bearing clearances.

• 대한토목학회논문집
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• 제11권3호
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• pp.47-58
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• 1991

본 논문에서는 무한요소를 이용한 지반-구조물 상호작용 해석에 대하여 연구하였다. 적층지반(Layered Soil)과 같이 여러 가지 응력파가 동시에 전파되는 탄성지반의 외부영역을 효과적으로 모형화할 수 있는 동적무한요소를 개발하였으며, 요소행렬 구성시 수반되는 무한대 방향으로의 적분을 효과적으로 수행하기 위하여 Gauss-Laguerre 적분방법을 기초로 하여 새로이 고안된 적분방법을 제시하였다. 이 방법의 타당성은 반무한 탄성지반과 적층된 반무한 탄성지반 위에 놓여 있는 원형강판의 임피던스(Impedance) 함수를 구하여 해석적으로 구한 값들과 비교함으로써 검토하였다.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2000년도 추계공동학술대회논문집
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• pp.711-727
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• 2000

본 논문에서는 레이다 및 EW수신시스템에서 사용하는 SDLA를 5-7㎓(C-Band)의 RF 주파수대에서 설계 구현하였다. 구현한 SDLA의 특성은 -80㏈m-0㏈m의 동작범위를 얻었고, $\pm$1.2㏈이하의 대수오차, 19.2㎷/㏈의 대수기울기, 출력전압 범위는 0-l.53V, 2.0:1 이하의 VSWR, 약2㏈의 잡음지수와 900$\Omega$의 비디오 임피던스를 얻었다.