• Agricultural and Biosystems Engineering
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• v.3 no.1
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• pp.18-28
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• 2002

Neural network based models were developed and evaluated for predicting corn yield from aerial images based on 1998 and 1994 image data. The model used images in multi-spectral bands such as R, G, B, and IR (Red, Green, Blue and Infrared). The inputs to the neural network consisted of mean and standard deviation of multispectral bands of the aerial images. Performances of several neural network architectures using back-propagation with momentum were compared. The maximum yield prediction accuracy obtained was 97.81%. The BPNN model prediction accuracy could be enhanced by using more number of observations to the model, other data transformation techniques, or by performing optical calibration of the aerial image.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.04a
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• pp.130-135
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• 1995

Wind-induced vibration of buildings with viscoelastic dampers are studied analytically. The added viscoelastic dampers change the damping distribution and reduce the response of buildings. The distribution of damping resistance that results from these viscoelastic dampers is known as non-classical or non-proportional. Non-classically damped structures are analyzed by state-space approach. However, this approach is complex and time-consumming compared to classical approach. This paper is aimed at the analysis of wind-induced Vibration Of buildings With Viscoelastic dampers. The Process Of State-Space approach is studied and the approximate analysis is suggested to overcome the complex and time-consuming access. For numerical certification, PSDF(Power Spectral Density Function) is obtained. Autocorrelation function is obtained in time domain and PSDF is obtained by fourier transformation of this function in frequency domain. It is found that Approximate method can give close approximation to exact solution.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.2
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• pp.495-513
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• 2020

The correlation identification of the subsurface is a novel electrical prospecting method which could suppress stochastic noise. This method is increasingly being utilized by geophysicists. It achieves the frequency response of the underground media through division of the cross spectrum of the input & output signal and the auto spectrum of the input signal. This is subject to the spectral leakage when the cross spectrum and the auto spectrum are computed from cross correlation and autocorrelation function by Discrete Fourier Transformation (DFT, "To obtain an accurate frequency response of the earth system, we propose an improved correlation identification method which uses all phase Fast Fourier Transform (APFFT) to acquire the cross spectrum and the auto spectrum. Simulation and engineering application results show that compared to existing correlation identification algorithm the new approach demonstrates more precise frequency response, especially the phase response of the system under identification.

• Wind and Structures
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• v.15 no.3
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• pp.223-245
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• 2012

Multivariate simulation is necessary for cases where non-Gaussian processes at spatially distributed locations are desired. A simulation algorithm to generate non-Gaussian wind pressure fields is proposed. Gaussian sample fields are generated based on the spectral representation method using wavelet transforms method and then mapped into non-Gaussian sample fields with the aid of a CDF mapping transformation technique. To illustrate the procedure, this approach is applied to experimental results obtained from wind tunnel tests on the domes. A multivariate Gaussian simulation technique is developed and then extended to multivariate non-Gaussian simulation using the CDF mapping technique. It is proposed to develop a new wavelet-based CDF mapping technique for simulation of multivariate non-Gaussian wind pressure process. The efficiency of the proposed methodology for the non-Gaussian nature of pressure fluctuations on separated flow regions of different rise-span ratios of domes is also discussed.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.2
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• pp.122-130
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• 1996

In an effort to learn more about the reaction mechanisms which lead to the compound nucleation at the interface of cobalt and silicon, electrical noise properties has been investigated for cobalt thin films deposited on silicon substrates by the electron beam evaporation and rf sputtering techniques. Microstructural variations at the Co/Si interfaces have been observed by transmission electronmicroscopy. Amorphous structures are observed at the Co/Si interfaces for samples whose cobalt thicknesses are less than 4nm and a polycrystalline compound nucleation has been occurred for thicker films. 1/f noise power same samples, and the spetral density has been normalized. The amplitude of 1/f noise power spectral density shows a gradual increase as the cobalt thickness is increased, and the amplitude has dropped abruptly after the compound nucleation. The variations of the noise parameters areassumed to be an indiction of the phase transformation along the nucleation reaction path, and amplitude has been interpreted as instabilities of the Co/Si interfacial structures.

• Journal of applied mathematics & informatics
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• v.26 no.5_6
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• pp.1101-1121
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• 2008

One proposes an approach to fractional Fourier's transform, or Fourier's transform of fractional order, which applies to functions which are fractional differentiable but are not necessarily differentiable, in such a manner that they cannot be analyzed by using the so-called Caputo-Djrbashian fractional derivative. Firstly, as a preliminary, one defines fractional sine and cosine functions, therefore one obtains Fourier's series of fractional order. Then one defines the fractional Fourier's transform. The main properties of this fractal transformation are exhibited, the Parseval equation is obtained as well as the fractional Fourier inversion theorem. The prospect of application for this new tool is the spectral density analysis of signals, in signal processing, and the analysis of some partial differential equations of fractional order.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.4
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• pp.355-360
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• 2007

The process of the nonlinear shallow water wave transformation in a basin of a constant depth is studied. Characteristics of the first breaking of the wave are analyzed in details. The Fourier spectrum and steepness of the nonlinear wave are calculated. It is shown that the spectral amplitudes can be expressed using the wave front steepness, which allows the practical estimations.

• Korean Journal of Veterinary Research
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• v.46 no.1
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• pp.47-55
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• 2006

To evaluate method for monitoring anesthetic depth with quantitative electroencephalography (q-EEG), we recorded processed EEG (raw EEG) and pain score till 100 minutes in beagle dogs anesthetized for 60 minutes with propofol (n = 5, PRO group), isoflurane (n = 5, ISO group) and propofol-ketaminefentanyl (n = 5, PFK group). Raw EEG was converted into 95% spectral edge frequency (SEF) by fast Fourier transformation (FFT) method. We investigated anesthetic depth by comparing relationship (Pearson's correlation) between q-EEG (95% SEF) and pain score. Pearson's correlation coefficients are +0.2372 (p = 0.0494, PRO group), +0.79506 (p < 0.001, ISO group) and +0.49903 (p = 0.0039, PFK group).

• Bulletin of the Korean Chemical Society
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• v.23 no.8
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• pp.1111-1115
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• 2002

The photoluminescence of calixarene crystals has been studied as functions of temperature, time, and concentration. The vibronic bands shift to longer wavelength and become significantly sharper as temperature decreases. The experimental results r eveal that the structural transformation occur during the annealing process. Time-resolved spectra of calixarene at 12 K are monitored. Spectral features, which demonstrate characteristic of energy transfer processes, are not observed. The depopulation of excited state density is mainly controlled by unimolecular decay process dominating other decay processes. The lifetime was found to be 2.6 $\pm$ 0.1 ns. For the case of calixarene mixed with naphthalene, the fluorescence spectrum shows that the band centered at 340 nm lies 2840 $cm^{-1}$ below the relatively broad 310 nm band found for calixarene crystals. The spectra also exhibit that the emission intensity increases with increasing calixarene concentration. The results are evident that the calixarene emission is quenched by the naphthalene. Phosphorescence of calixarene mixed with naphthalene crystals is observed to determine whether the emission is due to naphthalene. The phosphorescence peaks were compared with the ground-state vibrational frequencies of naphthalene and found to be in good agreement. The results indicate that inter-molecular energy transfer occurs between calixarene and naphthalene.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.247-248
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• 2007

본 논문에서는 이미지 센서의 Channel Spectral Sensitivity 특성과 CIE-Color Matching Function과의 관계를 고려하여, Color를 재구성함으로써 기존 영상의 색 정보를 그대로 복원하고, Color Error를 줄이는 방법을 제안한다. 특히 색변환 과정 중 Color Error를 줄일 때, 영상의 Edge와 Noise를 판별하여 Noise boost-up을 방지하고, 화질을 개선하는 방안을 제시한다.