• Journal of Korea Game Society
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• v.12 no.1
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• pp.123-132
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• 2012

There are many of games using smart devices. Voice recognition is can be useful way for input. In the game, voice have to be quickly recognized, at the same time it have to be manipulated promptly as well. In this study, we developed the optimized real-time phoneme recognition using max flow matching that it can be efficiently used in the game field. Firstly, voice wavelength is transformed to FFT, secondly, transformed value is made by a graph in Z plane, thirdly, data is extracted in specific area, and then data is saved in database. After all the value is recognized using weighted bipartite max flow matching. This way would be useful method in game or robot field when researchers hope to recognize the fast voice recognition.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.4
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• pp.315-319
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• 2001

A diagnosis system that provides early warnings regarding machine malfunction is very important for rolling mill so as to avoid great losses resulting from unexpected shutdown of the production line. But it is very difficult to provide e8rly w, ul1ings in rolling mill. Because dynamics of rolling mill is non-linear. This paper shows a chaotic behaviour of vibration signal in rolling mill using embedding method. Phase plane and Poincare map, FFT and histogram of vibration signal in rolling mill are implemented by qualitative analysis and Fractal dimension, Lyapunov exponent are presented by quantitative analysis.

• Journal of Korea Multimedia Society
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• v.5 no.3
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• pp.263-271
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• 2002

In this paper, we propose a new smoothing method for removing moire patterns using analysis of halftone patterns interference. The proposed method can determine a strength of moire patterns by using gray values of pixels and the size of smoothing mask for moire region is adjusted adaptively according to the strength of moire patterns. Therefore it can remove moire patterns effectively and preserve meaningful high frequencies well, such as edges and textures. The proposed method only refer to predefined lookup table to determine the strength of moire patterns, so it is more efficient than a previous work based on FFT of subblock. It could be applied to field of various multimedia applications that deal with color prints.

• Journal of the Korea Society of Computer and Information
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• v.15 no.12
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• pp.19-26
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• 2010

In this paper, we studied about the Embedded System of the biosignal measurement and analysis to sensibility evaluation in daily life for non-intrusive. This system is two kinds of measuring biosiganls(Electrocardiogram:ECG, Photoplethysmography:PPG) and analyzed by real-time wireless transmission to notebook PC using bluetooth for consistent and reliability of physiological way to assess continuously changing sensibility. Comparative studied of an autonomic nerve system activity ratio on characteristics frequency band of two kinds of biosignal analyzed frequency way using the Fast Fourier Transform(FFT) and Power Spectrum Density(PSD). Also the key idea of this system is to minimize computing of analysis algorithm for faster and more accurate to assess the sensibility, and the result of the visualization using graph. In this paper, we evaluated the analysis system to assess sensibility that measuring various situation in daily life using a non-intrusive biosignal measurement system, and the accuracy and reliability in comparison with difference of result by development analysis system.

• The Journal of the Acoustical Society of Korea
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• v.28 no.7
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• pp.653-660
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• 2009

This paper proposes a robust audio watermarking algorithm for copyright protection and improvement of sound quality after embedding a watermark into an original sound. The proposed method computes the FFT (fast Fourier transform) of the original sound signal and divides the spectrum into a subbands. Then, it is necessary to calculate the energy of each subband and sort n subbands in descending order corresponding to its power. After calculating the energy we choose k subbands in sorted order and find p peaks in each selected subbands, and then embed a length m watermark around the p peaks. When the listeners hear the watermarked sound, they do not recognize any distortions. Furthermore, the proposed method is robust as much as Cox's method to MP3 compression, cropping, FFT echo attacks. In addition to this, the experimental results show that the proposed method is generally 10 dB higher than Cox's method in SNR (signal-to-noise ratio) aspect.

• The Journal of the Acoustical Society of Korea
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• v.40 no.5
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• pp.473-478
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• 2021

Vibrato corresponds to a modulation of frequency and is one of the most frequently used techniques to enrich vocal and musical instrument sounds. Whereas the fundamental frequency trajectories of vibrato tones are generally modeled as a sinusoid, they are sometimes observed to be non-sinusoidal. In this paper, we propose a method to analyze the characteristics of non-sinusoidal fundamental frequency trajectories of vibrato sounds. The proposed method performs Fast Fourier Transform (FFT)-based harmonic analysis on the frequency trajectory, analyzes vibrato parameters, and calculates a sinusoid purity factor. We applied the proposed method to flute, viola, and saxophone vibrato tones, whose results showed the effectiveness of the proposed method.

• The Journal of the Acoustical Society of Korea
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• v.5 no.2
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• pp.19-28
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• 1986

DSP LSE을 이용하여 디지털 DTMF 수신기를 구현하는 방법으로는 IIR 디지털 필터, Counter 방법, DFT 방법, FFT 방법 및 PARCOR 방법등이 제안되어 왔다. 그 중에서도 IIR 디지털 필터를 이용 한 방법은 기존의 아나로그 DTME 수신기를 그대로 디지털화 한 것이기 때문에 성능이 제일 우수한 것 으로 알려져 있다. 그러나 IIR 디지털 필터를 이용하여 그것을 구현할 때 필터의 계수, roundoff 잡음, overflow 등 고려해야 할 사항이 많다. 본 논문에서는 이러한 문제점들을 해결하면서 CCITT 사양들을 만족하는 디지털 DTMF 수신기 구현에 관한 연구결과를 제시하였다. DSP LSI을 이용해서 수신기를 hardware 제작할 때 이 결과들을 수정없이 이용할 수 있다고 기대된다.

• Korean Security Journal
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• no.61
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• pp.377-400
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• 2019

Photography is the most commonly used method of documenting the crime and incident scene as it helps maintaining chain of custody (COC) and prove integrity of the physical evidence. It can also capture phenomena as they are. However, digital images can be manipulated and lose their authenticity as admissible evidence. Thus only limited techniques can be used to enhance images, and one of them is Fourier transform. Fourier transform refers to transformation of images into frequency signals. Fast Fourier transform (FFT) is used in this study. In this experiment, we overlapped fingerprints with graph paper or other fingerprints and separated the fingerprints. Then we evaluated and compared quality of the separated fingerprints to the original fingerprints, and examined whether the two fingerprints can be identified as same fingerprints. In the case of the fingerprints on graph paper and general pattern-overlapping fingerprints, fingerprint ridges are enhanced. On the other hand, in case of separating complicated fingerprints such as core-to-core overlapping and delta-to-delta overlapping fingerprints, quality of fingerprints can be deteriorated. Quality of fingerprints is known to possibly bring negative effects on the credibility of examiners. The result of this study may be applicable to other areas using digital imaging enhancement technology.

• Journal of Satellite, Information and Communications
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• v.9 no.1
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• pp.22-27
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• 2014

In this paper, we analyzed performance of FFT based on pilot sensing scheme for DTV signal in fading environments. In order to detect the present and absent for advanced television system committee digital television (ATSC DTV), a pilot detection scheme based on FFT is employed. Also, these signals are applied to each fading environment. For evaluating the spectrum sensing performance, detection probability is derived. When threshold is decided, we refer to constant false alarm rate (CFAR) scheme. From simulation results, it is confirmed that the spectrum sensing performance is improved as increase of the false alarm rate. The result of this paper can be applied to implement the spectrum sensing part of cognitive radio (CR) systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.2
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• pp.294-299
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• 2002

This paper presents a faults diagnosis technique of induction motors based on a neural network. Only stator current is measured, transformed by using FFT and normalized for the training. Healthy, bearing fault, stator fault and rotor end-ring fault motors are prepared to obtain the learning data and diagnose the several faults. For more effective diagnosis, the load rate is changed by 100%, 60%, 30% of full load and the obtained are applied to the teaming process. The experimental results show the proposed method is very detectable and applicable to the real diagnosis system.