• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.75-78
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• 2006

GF(2)위에서 최대길이를 갖는 n-셀 90/150 셀룰라 오토마타의 각 셀은 길이가 $2^n-1$인 수열을 생성한다. 이러한 셀룰라 오토마타의 임의의 셀에 대한 출력수열은 다른 셀에 대한 출력수열의 위치를 이동함으로써 얻을 수 있다. 본 논문에서는 주어진 셀룰라 오토마타의 상태전이행렬의 특성다항식에 의한 동차 선형점화식을 만족하는 충격반응수열을 이용하여 셀들의 위상이동차를 계산하는 알고리즘을 제안한다.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.11
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• pp.188-193
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• 2003

To predict changes in biomechanical parameters such as intradiscal pressure, and the shock absorbing mechanism in the spinal motion segment under different impact duration/loading rates, a three dimensional L3/L4 motion segment finite element model was modified to incorporate the poroelastic properties of the motion segment. The results were analyzed under variable impact duration for normal and degenerated discs. For short impact duration and a given maximum compressive force, relatively high cancellous pore pressure was generated as compared with a case of long impact duration, although the amount of impulse was increased. In contrast relatively constant pore pressure was generated in the nucleus. Disc degeneration increased pore pressure in the disc and decreased pore pressure in the cancellous core, which is more vulnerable to compressive fracture compared with intact case.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.4 s.121
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• pp.363-369
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• 2007

The purpose of the study is to obtain acoustical information to prevent eavesdropping of the glass window. Speech intelligibility was investigated on the vibration sound detected from the glass window of a conference room. Objective test using speech transmission index(STI) was performed to estimate quantitatively the speech intelligibility. STI was determined based on tile modulation transfer function(MTF) of the room-glass window system. Using Maximum Length Sequency(MLS) signal as a sound source, impulse responses of the glass window and MTF were determined by signals from accelerometers and laser doppler vibrometer. Finally, speech intelligibility of the interior sound and window vibration were compared under different sound pressure levels and amplifier gains to confirm the effect of measurement condition on the speech intelligibility.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.10
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• pp.542-549
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• 2004

The conventional fault location algorithms based on the travelling waves have an inherent problem. In cases of the close-up faults occurring near the relaying point and of the faults having zero degree inception angle of voltage signals, the conventional algorithms can not estimate an accurate fault distance. It is because the shapes of travelling waves are near sinusoidal in those cases. A new method solving this problem is presented in this paper. An FIR(Finite Impulse response) filter which makes high frequency components prominent and makes the power frequency component and dc-offset attenuated is used. With this method, the cross-correlation peak is to be very clear when a close-up fault or a fault having near zero-degree inception angle occurs. The cross-correlation peaks can be clearly distinguished and accurate fault location is practically possible consequently. A series of simulation studies using EMTP(Electromagnetic Transients Program) show that the proposed algorithm can calculate an accurate fault distance having maximum 2% or less error.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.4
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• pp.422-432
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• 1992

Previous investigations of redundant manipulators have often focussed on local optimization for redundancy resolution by using the Jacobian pseudoinverse to solve the instantaneous relationship between the joint and end-effector velocities. This paper establishes some new goals for redundancy resolution at position level by using configuration control approach which has been recently developed. Minimum gravity loading, joint limit avoidance, minimum sensitivity, maximum stiffness and minimum impulse are introduced as redundancy resolution goals. These new goals for redundancy resolution allow more efficient utilizations of the redundant joints based on the desired task requirements. Simple computer simulation examples are given for illustration.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.96.1-96
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• 2001

This paper is shown that the impulse and unit step response of second-order system can be computed by the analytic methods using Laplace transform. Also, the transient response specifications are explicitly formulated by the peak undershoot and maximum overshoot of the step response. Three different second-order systems are investigated: prototype system, system with LHP(left half plane) real zero, and system with RHP(right half plane) real zero. Based on these analytic results, this paper presents the sufficient and necessary conditions for the second-order linear SISO(single-input/single-output) stable system to have the nonovershooting or monotone nondecreasing step response.

• 한국가시화정보학회:학술대회논문집
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• 2004.11a
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• pp.72-75
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• 2004

The present study describes a computational work to investigate detailed behaviors of the twin shock waves discharged from the exits of two-parallel ducts. In computations, the Yee-Roe-Davis's TVD scheme was used to solve the unsteady, three-dimensional, inviscid, compressible, Euler equations. The distance between two ducts is varied and the Mach number of the incident shock wave is changed below 2.0. The results obtained show that on the symmetric axis between two-parallel ducts, the maximum pressure achieved by the merge of twin shock waves and its location strongly depend upon the distance between two-parallel ducts and the Mach number of the incident shock wave. It is also found that the twin shock waves discharged from the exits of two-parallel ducts leads to the complicated flow fields, such as Mach stem, spherical waves, and vertical structures.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.7
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• pp.826-835
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• 1988

In this paper, we analyze the generation of an image pyramid as a 2-dimensional decimation-interpolation process, and suggest a performance index of FIR filter for decimation and interpolation filter. Until now, most deciamtion and interpolation filters are designed via the approximation of the impulse response of an ideal filter. In this paper, however, we propose a new performance index that minimizes the maximum frequency-weighted mean square error between the desired and the generated interpolated signal, and propose an optimal half-band filter based on the proposed performance index as an example. Some simulation results with real images show that the proposed optimal half-band filter yields a higher PSNR as well as the more preferable image quality, in comparison with other currently used filters with the same computational complexity.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.14-16
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• 2007

The statistics for the Gaussian noise mixed with impulsive noise are modelled. The denoising algorithm called amplitude-limited sample average filter is derived, which is optimal in terms of minimizing mean square errors under the assumption that contaminating noise is heavy-tailed Gaussian distributed. Its performance is shown to be excellent when image is corrupted mainly with Gaussian noise. However, it shows visually grainy output as the amount of impulsive noise increases. In order to overcome such problems, it is combined with the myriad filter to propose an amplitude-limited myriad filter. Simulation shows it effectively removes both Gaussian and impulsive noise, not blurring edges severey.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.516-517
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• 2010

최근에 들어 반도체 및 디스플레이 분야를 포함하여 태양전지와 같은 신재생 에너지 분야에서 고품질, 고기능성 박막이 많이 사용되고 있으며, 이에 따라 플라즈마 제어기술 및 코팅 공정기술 개발에 대한 요구가 증가하고 있다. 산업기술이 고도화됨에 따라 다양한 계열의 박막이 필요하게 되었고 고밀도의 플라즈마를 공급하고 안정된 공정을 진행하기 위해 순시적인 플라즈마 제어가 가능한 임펄스 전원장치에 대한 연구가 활발히 진행되고 있다. 기존의 임펄스 전원장치에서는 플라즈마 발생에 필요한 고전압 발생만 관점을 두고 있으나 플라즈마의 발생뿐이 아니라 증착율이 높은 상태로 유지되어야 실제 공정의 효율이 증가한다. 본 연구에서는 증착 효율을 극대화하기 위하여 별도의 저압회로를 부가한 복합형 임펄스 전원장치를 제안한다.