• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.411-416
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• 2004

This paper introduces a fast Fourier transform (FFT)-based spectral analysis method for the transient responses as well as the steady-state responses of linear dynamic systems with non-proportional damping. The force vibration of a non-proportionally damped three-DOF system is considered as the illustrative numerical example. The proposed spectral analysis method is evaluated by comparing with the numerical solution obtained by the Runge-Kutta method

• Journal of electromagnetic engineering and science
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• 제1권1호
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• pp.60-62
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• 2001

A novel approach for modeling the thermic endfire interstitial applicator is presented. A hypothetical semi-infinite circular cylinder is added in the endfire direction in order to facilitate the theoretical modeling approach. The Fourier transform and mode-matching technique is utilized to obtain a solution in fast-convergent series Numerical computations for the input impedance are performed to check the Validity of the theoretical model.

• 한국군사과학기술학회지
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• 제10권2호
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• pp.100-106
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• 2007

In this paper, the performance of OFDM(Orthogonal Frequency Division Multiplexing) and FMT(Filtered Multi-tone) Systems is compared under jamming environment. Two systems are multi-carrier systems to improve data rates. Through the comparison of two systems under jamming environment, the characteristics and strong/weak points of each system are analyzed.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.127-134
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• 1999

Vibration problem occurring at the metal deck floor system not only reduces the serviceability of a building but also reduces the usability of a floor system. Most problem occurring at the metal deck floor results from the human movement such as walking and running. However the vibration induced by running does not occur continuously except the special case. therefore the floor vibration due to walking was only considered on this paper,. Vibration occurring due to human walking was measured and the corresponding load function was derived through the Fast Fourier Transform(FFT)

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2003년도 하계학술대회 논문집
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• pp.134-136
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• 2003

This paper proposes an algorithm for fingerprint identification using phase only correlation. This algorithm uses the phase of fast Fourier transform and correlation function to calculate the similarity. The algorithm gives very clear result for identification because it shows only one conspicuous sharp peak for the same person's fingerprint. Further, it shows good results even for the finger print images which are printed not clearly and does not need to preprocess the images. It also shows good results for parallel displacement of fingerprint. The experiment result shows the effectiveness of the proposed algorithm.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 1999년도 추계학술대회 논문집
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• pp.383-387
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• 1999

인간의 감성을 고려하는 제품의 생산에서 촉감은 인간이 제품을 만질 때 직접적으로 느낄 수 있는 중요한 감각이다. 이러한 촉감의 연구를 위해 직물을 대상으로 직물 표면의 거칠기를 측정하고 해석하였다. 측정된 표면 거칠기를 Fast Fourier Transform 변환하여 직물구조를 분석하는 기준으로 하였다. 각 peak 값들을 분석하여 나온 값이 직물 구조를 수식화하여 사용할 수 있는 좋은 방법이 됨을 알았다. 또한, 실의 잔털량을 측정하여, 잔털량과 인간의 주관적인 감각을 대표하는 값과의 상관관계를 조사하였다. 잔털량이 인간의 주관적인 감각을 객관적으로 표현할 수 있는 한 요소로 사용될 수 있다는 것을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.1028-1034
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• 1989

A method of analysis of the steady-state performance of induction motor with supply voltage controlled by cyclically-triggered inline thyristors is presented. Phase-variable model and asymmetrical components are not used in this analysis. Instead, Fast Fourier Transform technique and the method of multiple reference frames are employed to obtain the constant-speed performance of I.M. easily.

• Journal of the Optical Society of Korea
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• 제19권4호
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• pp.334-339
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• 2015

Terabit-per-second (Tb/s) transmission capacity for the next generation of long-haul communication networks can be achieved using multicarrier optical super-channel technology. In an elastic orthogonal frequency division multiplexing (OFDM) super-channel transmission system, demultiplexing a portion of an entire spectrum in the form of a subband with minimum power is critically required. A major obstacle to achieving this goal is the analog-to-digital converter (ADC), which is power-hungry and extremely expensive. Without a proper ADC that can work with low power, it is unrealistic to design a 100G coherent receiver suitable for a commercially deployable optical network. Discrete Fourier transform (DFT) is often seen as a primary technique for understanding partial demultiplexing, which can be attained either optically or electronically. If fairly comparable performance can be achieved with an all-optical DFT circuit, then a solution independent of data rate and modulation format can be obtained. In this paper, we investigate two distinct OFDM super-channel receiver models, based on electronic and all-optical DFT-technologies, for partial carrier demultiplexing in a multi-Tb/s transmission system. The performance comparison of the receivers is discussed in terms of bit-error-rate (BER) performance.

• 한국소음진동공학회논문집
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• 제24권6호
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• pp.476-482
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• 2014

The stress analysis of the pipeline is required in any kind of plant for its safe operation. For this, the displacement vibration data measured at many locations of the pipeline should be provided. In reality, the installation of the non-contact type displacement sensors such as laser displacement sensors or eddy current type proximity sensors in a narrow and confined region in the vicinity of the pipeline is almost impracticable. In this work, the general purpose piezo-ceramic accelerometers were attached on the measuring points on the pipeline and the acceleration vibration signal was acquired. The measured acceleration signal was low pass filtered and then downsampled. The resulting acceleration signal was transformed into both the time-domain and frequency-domain displacement signal utilizing the fast Fourier transform techniques. All the procedures are presented in detail. It is demonstrated that the measurement of the pipeline acceleration by using contact type accelerometers can be made for the purpose of providing the required displacement data for the stress analysis of the pipeline.

• 대한화학회지
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• 제35권6호
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• pp.713-719
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• 1991

푸리에 변환을 이용하여 100kHz의 주파수 범위까지 사용할 수 있는 전기화학적 임피던스 측정시스템을 제작하였다. 이 시스템은 신호 발생기, 특수하게 고안된 정전위기, 고속 자료수집 장치, 시스템 제어기 및 컴퓨터 인터페이스로 구성되었다. 우리가 제작한 시스템은 lock-in amplifier를 사용하는 상품과 성능이 비슷하였다. 측정에 소요되는 최소 시간은 사용된 최적 주파수의 한 주기에 해당하므로 상당히 짧아졌다. 이 시스템을 사용하면 부식 초기와 같이 시간에 따라 변하는 전기화학적 계면현상을 임피던스 측정법으로 연구할 수 있으리라 전망된다.