• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1628-1630
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• 1997

The purpose of this study is to see the method of the analysis of EEG(Electroencephalography) whcih is a nonlinear system, to quantize human emotion under color stimulation using the analysis of EEG. The result of this study would be used clinical study and development fo image instruments with color. In this study, the method of the analysis of EEG is power spectrum using FFT(Fast Fourier Transform) and the modelling of EEG under color stimulation base on back propagation Neural Networks ond of AI(Artfical Intellignece) skills. First, input layer make a match to relative power which get analyzing s in 4 channels, and output layer make a match to color stimulation which is measured human emotion. Finally, weights of each neurons determine by learing back porpagation Neural Networks.

• KSTLE International Journal
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• 제6권1호
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• pp.17-20
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• 2005

The object of the present work is the natural lre%uency analysis of femto slider, HeaHdisk interaction during starustop and constant speed were detected by using the acoustic emission (AE) test system. The frequency spectrum analysis wasperformed using the AE signal obtained during the head/disk interaction. The FFT (Fast Fourier Transform) analysis of the AEsignals is used to understand the interaction between the AE signal and the state of contact. Natural frequency analysis wasperformed using the ANSYS program. The results indicate acceptable accordance of finite element calculation results with theexperimental results.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.32-41
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• 1999

In this study, a new knocking control algorithm was developed using the knock threshold value auto-correction algorithm. This algorithm uses the Fast Fourier Transform9FFT) method by measuring cylinder block vibration signals of a 1498 cc four-cylinder spark ignition engine. The experimental results show the proposed knock control algorithm provides improved performance compared to existing methods. The results also show that the proposed FFT algorithm provides real-time adjustment of the knock threshold value.

• 대한의용생체공학회:의공학회지
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• 제10권3호
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• pp.293-302
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• 1989

A Dual Sensor Wiener Filter technique was used to improve the image quality of the scanning type digital radiographic system (resolution and SNR). In this method, two images were acquried simultaneously using two sensors with high and low resolution and SNR values. Using the cross Power spectrum between dual sensor outputs of the same chest radiographic image. we design a new type of Wiener Filter and implement it with fast algorithm. We compared the performance of this new dual sensor filter with conventional single sensor filters (Wiener Filter and Parametric Projec- tion Filter) . In simulation studies, it is shown that this new method has SNR improvement of 1-3 dB better than conventional filters.

• 한국정보보호학회:학술대회논문집
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• 한국정보보호학회 2001년도 종합학술발표회논문집
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• pp.464-468
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• 2001

In this paper, we propose a robust watermarking technique that accepts time scaling, pitch shift, add noise and a lot of lossy compression such as MP3, AAC, WMA. The technique is developed based on digital filtering. Being designed according to critical band of HAS (human auditory system), the digital filters nearly affect audio quality. Furthermore, before implementing digital filtering, wavelet transform decomposes the audio signal into several signals that is composed of specific frequencies. Designed digital filters scan the decomposed signal. The designed digital filter, band-stop filter, distorts and eliminates specific frequencies of audio signals. Watermarking detection can be accomplished by FFT (Fast Fourier Transform). Firstly, segments of audio signal are transformed by FFT. Then, the obtained amplitude spectrum by FFT is summed repeatedly. Finally the watermark detector can find filters used to watermark encoding based on eliminating frequencies. The suggested technique can embed 4bits/s in a robust manner.

• 대한의용생체공학회:의공학회지
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• 제11권2호
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• pp.243-248
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• 1990

EMG (eleltromyographic) signals are generated by contracting muscle and detected in and out side of muscle in the form of random signals. In the measurement of muscle fatigue, the mean frequency of EMG signals using spectrum analysis is an important parameter in diagonosis of muscle disease and in sports medicine fields. In this study, the degree of spectral transfer to lower frequency caused by accumulation of Latic acid inside the muscle is estimated. The new spectral analysis method using 2"d order hAaximum Entropy Method was applied to estimate the mean frequency and we confirmed that this new method yields fast and reliable estimation.tion.

• KSTLE International Journal
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• 제5권1호
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• pp.28-31
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• 2004

The object of the present work is the natural frequency analysis of subambient pressure tri-pad and pico sliders. Head/disk interaction during start/stop and constant speed were detected by using the acoustic emission (AE) test system. The frequency spectrum analysis is performed using the AE signal obtained during the head/disk interaction. The FFT (Fast Fourier Transform) analysis of the AE signals is used to understand the interaction between the AE signal and the state of contact. Natural frequency analysis was performed using the Ansys program. The results indicate acceptable accordance of finite element calculation results with the experimental results.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2010년도 제42차 하계학술발표논문집 18권2호
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• pp.39-42
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• 2010

본 연구에서는 두 파장을 이용한 광적용적맥파(photoelectric plethysmography, PPG)의 시스템을 기반으로 산소포화도 및 다양한 맥파 관련 건강정보를 분석할 수 있는 시스템에 관하여 연구하였다. 광적용적맥파를 이용한 산소포화도 측정을 위해 서로 다른 두 파장의 빛을 이용하여 비 침습적 맥파 측정 방식으로 손가락 끝 부분에서 측정하고, 혈액 내 헤모글로빈의 빛 대한 광흡수도의 차이를 분석하여 검출하였다. 또한 정확한 분석을 위하여 두 파장의 빛을 순차적으로 제어하는 스위칭 기법을 사용하고, 조직을 통과한 두 파장의 빛을 분리하기 위하여 수광부에 시간의 차이를 두어 각 파장에 대한 광전용적맥파를 측정하였다. 본 연구에서는 산소포화도를 측정하기 위한 방법으로 서로 다른 두 파장을 이용한 광전용적맥파 측정기기를 설계하고, 측정 결과의 정확성 및 유의성에 대한 검증하였다.

• IEIE Transactions on Smart Processing and Computing
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• 제3권3호
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• pp.135-141
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• 2014

The inherent feature of the highly efficient spectrum usage has made Orthogonal Frequency Division Multiplexing (OFDM) preferable for Communication Standards. This study evaluated the performance of a Least Square (LS) estimator for a comb-type pilot insertion scheme over a fast fading Rayleigh channel. A High Peak-to-Average Power Ratio (PAPR) is one of the major downsides of the OFDM. The effects of an increase in the number of subcarriers on PAPR and the performance of the LS Estimator were studied. Increasing the number of subcarriers while keeping the pilots overhead constant resulted in improved performance of the LS estimator but the PAPR increased with increasing number of subcarriers. Therefore some trade-off between the number of subcarriers and the performance of the OFDM system is needed. The Mean Square Error (MSE) expression was also derived for the LS estimator in the case of a comb-type pilot arrangement. The MSE expression clearly explains the effects of the number of subcarriers on the performance of the LS estimator.

• 한국통신학회논문지
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• 제16권11호
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• pp.1054-1062
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• 1991

본 논문에서는 강한 임펄스성 잡음 및 협대역의 간섭이 존재하는 전력선 채널에서의 데이터 전송을 위하여 직접 시퀀스 스펙트럼 확산 통신 방식을 이용한 통신 시스템을 구성하였다. 디지털 정합 필터를 이용하여 버스트형 패킷의 빠른 코드 동기를 수행하도록 하였고, 코드 동기를 이룬 후 샘플링 펄스에 의해 데이터를 결정함으로써 버스트형 패킷을 복구하였다. 전력선 통신 시스템의 성능 측정을 위하여 매우 강한 임펄스성 잡음이 존재하는 모의 채널에서 전치 부호 1비트, 데이터 63비트로 구성된 패킷을 전송하였다. 매우 열악한 채널 조건으로서 신호 레벨보다 약 30[dB] 정도 큰 임펄스성 잡음이 연속적으로 발행하는 경우에도 $10^3$- $10^4$의 비트 오율과 0.07 이하의 패킷 손실율을 유지 하였다.