• 한국정보과학회논문지:소프트웨어및응용
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• 제34권12호
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• pp.1037-1044
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• 2007

최근 내용 기반 음악 검색 시스템에서는 사용자의 응답 시간을 단축시키기 위해 음악의 대표성을 갖는 선율을 추출하여 색인하고, 검색 시 이를 사용한다. 기존 연구에서는 미디(midi) 데이타를 이용하여 대표 선율을 추출하는 방법이 제안되었으나, 미디 데이타에 한정되는 단점이 있었다. 따라서 본 논문에서는 디지털 신호처리를 이용하여 모든 오디오 파일 포맷에 적용 가능한 대표 선율 검색을 제안한다. 대표 선율 검색을 위해 FFT(Fast Fourier Transform)을 이용하여 박자와 마디를 찾고 각 마디들의 PCM 데이타로부터 높은 수치가 나타나는 빈도를 측정한다. 이때 높은 수치들이 가장 많이 뭉쳐 있는 영역에서 여덟 마디 간격이 오디오 데이타의 대표 선율 영역이다. 제안 방법의 유효성을 검증하기 위한 실험으로 총 1000곡을 선택하여 대표 선율을 추출하였고, 그 결과 템포를 찾아낸 737곡 중 79.5%의 정확성을 보였다.

• 한국소음진동공학회논문집
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• 제20권9호
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• pp.863-875
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• 2010

The vibration of a cylindrical shell is generated due to elastic waves propagating on the shell. Those elastic waves include propagating waves such as flexural, longitudinal and shear waves. Those also include non-propagating decaying waves, i.e. evanescent waves. In order to separate contributions of each type of waves to the data for the vibration of the cylindrical shell, spatial signal processing techniques for wavenumber analysis are investigated in this paper. Those techniques include Fast Fourier transform(FFT) algorithm, Extended Prony method and Overdetermined Modified Extended Prony method(OMEP). Those techniques have been applied to identify the waves from simulated vibration signals with various signal-to-noise ratios. Futhermore, the experimental data for in-plane vibration of the cylindrical shell has been processed with those techniques to identify propagating waves(longitudinal, shear and flexural waves) and evanescent waves.

• 한국산업안전학회:학술대회논문집
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• 한국안전학회 2000년도 춘계 학술논문발표회 논문집
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• pp.52-57
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• 2000

This paper discusses frequency analysis based on frequency spectrum in orthogonal cutting of fiber-matrix composite materials. A glass reinforced polyester (GFRP) was used as workpiece. Analysis method employs a force sensor and the signals from the sensor are processed using a fast Fourier transform (FFT) technique. The experimental correlation between the different chip formation mechanisms and model coefficients are then established. (omitted)

• 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 Communications and Networks
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• 제18권1호
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• pp.27-39
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• 2016

This paper derives and analyzes a novel block fast Fourier transform (FFT) based joint detection algorithm. The paper compares the performance and complexity of the novel block-FFT based joint detector to that of the Cholesky based joint detector and single user detection algorithms. The novel algorithm can operate at chip rate sampling, as well as higher sampling rates. For the performance/complexity analysis, the time division duplex (TDD) mode of a wideband code division multiplex access (WCDMA) is considered. The results indicate that the performance of the fast FFT based joint detector is comparable to that of the Cholesky based joint detector, and much superior to that of single user detection algorithms. On the other hand, the complexity of the fast FFT based joint detector is significantly lower than that of the Cholesky based joint detector and less than that of the single user detection algorithms. For the Cholesky based joint detector, the approximate Cholesky decomposition is applied. Moreover, the novel method can also be applied to any generic multiple-input-multiple-output (MIMO) system.

• 한국패류학회지
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• 제25권3호
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• pp.203-210
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• 2009

본 연구에서 우리는 다양한 종류의 패각을 사용하여 진주패각에서 나타나는 컬러 및 광학적 현상에 대해 비교 분석하였다. 다양한 종류의 패각의 진주층 단면 및 표면 SEM 이미지와 FFT 시뮬레이션을 수행했다. 그리고 반사율 측정을 통하여 패각에서 나타나는 광학적 현상에 대해 규명하고 패각의 광학적 현상에 의해 모패를 감별하기 위한 데이터를 구축하였다. 또한 패각의 진주층 구조에 기인한 회철현상을 바탕으로 하여 여러 각도의 분광반사율을 측정해서 보는 각도에 따라 패각의 색이 달라지는 현상에 대해 분석하였다.

• 대한전자공학회논문지
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• 제24권2호
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• pp.196-200
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• 1987

The following methods are proposed for implementing digital dual tone multi-frequency (DTMF) receiver: using infinite impulse response(IIR) digital filters, period-counting algorithm, discrete Fourier transform(DFT), and fast Fourier transform(FFT)[2]. The PARCOR(Partical Correlation) analysis method which has been widly used in the speech signal processing area is applied to the dual tone multi-frequency(DTMF) signal detection. This method is easy to implement digitally and stronger to digit simulation of speech than any other methods proposed up to date. Since sampling rate of 4KHz is used in the DTMF receiver for the detection of input DTMF signal originally sampled at 8KHz, it effects two times higher multiplexing efficiency.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.429-430
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• 2008

FFT(Fast Fourier Transform)는 멀티미디어 통신 및 디지털 신호처리 분야, 특히 무선통신이나 디지털 방송 등에서 쓰이는 OFDM(Orthogonal Frequency Division Multiplexing)에서 필수적인 역할을 하고 있다. 본 논문에서는 파이프라인 FFT 프로세서 설계의 다양한 알고리즘 및 하드웨어 구조에 대해 살펴보고 이를 한 눈에 파악할 수 있는 설계 가이드라인을 제시한다. 또한 분석 중 Radix-2 Single-path Delay Feedback의 복소곱셈기의 비효율적인 면을 찾고 새로운 R2SDF 구조를 제안한다.

• Structural Monitoring and Maintenance
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• 제1권1호
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• pp.69-87
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• 2014

A new output only modal analysis method is developed in this paper. This method uses continuous wavelet transform to modify a popular blind source separation algorithm, second order blind identification (SOBI). The wavelet modified SOBI (WMSOBI) method replaces original time domain signal with selected time-frequency domain wavelet coefficients, which overcomes the shortcomings of SOBI. Both numerical and experimental studies on bridge models are carried out when there are limited number of sensors. Identified modal properties from WMSOBI are analyzed and compared with fast Fourier transform (FFT), SOBI and eigensystem realization algorithm (ERA). The comparison shows WMSOBI can identify as many results as FFT and ERA. Further case study of structural health monitoring (SHM) on an arch bridge verifies the capability to detect damages by combining WMSOBI with incomplete flexibility difference method.

• 대한조선학회 특별논문집
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• 대한조선학회 2008년도 특별논문집
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• pp.96-105
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• 2008

Turbulent flow-induced vibrations generate the structural fatigue and noise problems. In this paper, using Corcos, Smol' yakov-Tkachenko, Ffowcs Williams and Chase models, the input power generated by distributed fluid force is predicted for power flow analysis (PFA) of turbulent flow-induced vibration. Additionally, the Fast Fourier Transform (FFT) is used to raise the calculation efficiency PFA results obtained are compared with the classical modal solutions for verifications. Analytic results using the fluid models show good agreements with those of modal analysis, respectively.