• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.88-89
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• 2014

In dynamic force microscopy, the cantilever oscillates at a resonant frequency, and the tip deflection is measured at this frequency. The cantilever deflection is, however, highly nonlinear, and the surface properties can be embedded in the deflection at the frequencies other than the original resonant frequency of the cantilever. Multifrequency atomic force microscopy includes the excitation and detection of the deflection in two or more frequencies which are higher harmonics or eigenmodes. This can overcome the limitations of conventional atomic force microscope. We reviewed the multifrequency atomic force microscopy and its applications in many fields.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1638-1642
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• 2003

In this paper, we have analyzed the power spectra and evaluate the performance of DTMF receiver by using the quick Fourier transform(QFT) algorithm. The economical signals detection of dual-tone multifrequency(DTMF) receiver is an important factor when developing cost-effective telecommunication equipment. In experimental results, it shows that reducing memory waste and can process the real-time.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.6
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• pp.579-585
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• 2009

The multifrequency eddy current testing(ECT) have been proposed various frequency mixing algorithms. In this study, we compare these approaches to frequency mixing of ECT signals from steam generator tubes; time-domain optimization, discrete cosine transform-domain optimization. Specifically, in this study, two different frequency mixing algorithms, a time-domain optimization method and a discrete cosine transform(DCT) optimization method, are investigated using the experimental signals captured from the ASME standard tube. The DCT domain optimization method is computationally fast but produces larger amount of residue.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.392-397
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• 1987

This paper concerns a method for micro-wave imaging. The image reconstruction of a perfect conducting cylinder by phase and amplitude measurement using the X-Band multifrequency is presented troll the simulated data. The high degree of range resolution is achieved using large signal band-width and cross-range resolution is obtained by doppler processing. The comparison of image reconstruction between range doppler processing and circular convolution algorithm is also shown.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.261-266
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• 1997

Nonevasive multifrequency microwave radiometry using coaxial waveguide antenna has been investigated for a homogeneous and four layer human body model. The coupling between coaxial waveguide antenna and a biological object was analyzed by use of the finite-difference time-domain(FDTD) method to obtain the absorbed power patterns in the media. The object studied in this paper was a homogeneous and four-layered lossy medium. The specific absorption rates(SAR) distribution which was corresponding to the temperature distribution was calculated in each region by use of the steady-state response in FDTD method. The SAR pattern of 1.2GHz was compared with that of 1.8GHz.

• International Journal of Computer Science & Network Security
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• v.21 no.2
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• pp.40-43
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• 2021

In the article of instability on the peak power level, duration and repetition period of a multifrequency space-time signal, we calculated the maximum values of the errors of the parameters of the laws of spatial-phase-frequency control. Requirements for the accuracy of the location of the phase centers of the emitters in a cylindrical phased array antenna with pyramidal horns; it is advisable to calculate the radiation field using single-stage and multi-stage distribution laws. The phase centers of individual radiation sources of a cylindrical phased array antenna have been studied; they have almost no effect on the duration and period of recurrence.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.199-200
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• 1996

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.11
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• pp.65-72
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• 1992

The economical detection of dual-tone multifrequency(DTMF) signals is a important when developing cost-effective telecommunication equipment. This paper propose that the modified M-channel Goertzel algorithm can reduces the real-time processing and memory waste. By using this M. G. algorithm, it will compare and evaluate to the performance of the digital DTMF receivers using the G. A.

• Journal of Biosystems Engineering
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• v.15 no.4
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• pp.281-289
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• 1990

A frequency-domain, system-identification method using a binary multifrequency signal was developed to find the transfer function between smoke intensity and throttle position in a diesel engine. This paper describes the simulation study performed to test the identification method developed. With an assumption of a diesel operation in a limited region about the normal operating state, the linear theory was adopted. Because that air fuel ratio is one of the most important operating variables causing smoke production in diesel combustion, single-input and single-output model was adopted.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.5
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• pp.690-698
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• 1990

Among the target identification algorithms presented up to now, the NNR algorithm utilize multifrequency and single observation method. But it is generally known that its implementation is extremely difficult. In this paper a new identification algorithm using the single frequency and cumulative observation method was proposed. The simulation result shows that the proposed algorithm with 31 observation and accumulation is more effective and realizable than the NNR with 3 freqnencies when the noise level n is below 0.3.