• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.559-568
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• 2017

Harmonic/inter-harmonic detection and analysis is an important issue in power system signal processing. This paper proposes a fast algorithm based on matching pursuit (MP) sparse signal decomposition, which can be employed to extract the harmonic or inter-harmonic components of a distorted electric voltage/current signal. In the MP iterations, the method extracts harmonic/inter-harmonic components in order according to the spectrum peak. The Fast Fourier Transform (FFT) and nonlinear optimization techniques are used in the decomposition to realize fast and accurate estimation of the parameters. First, the frequency estimation value corresponding to the maxim spectrum peak in the present residual is obtained, and the phase corresponding to this frequency is searched in discrete sinusoids dictionary. Then the frequency and phase estimations are taken as initial values of the unknown parameters for Nelder-Mead to acquire the optimized parameters. Finally, the duration time of the disturbance is determined by comparing the inner products, and the amplitude is achieved according to the matching expression of the harmonic or inter-harmonic. Simulations and actual signal tests are performed to illustrate the effectiveness and feasibility of the proposed method.

• Journal of the Korean Society for Railway
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• v.14 no.2
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• pp.130-136
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• 2011

This paper suggests realization method for real-time speech recognition using VoiceXML in telephony environment based on SIP for Railroad Reservation Service. In this method, voice signal incoming through PSTN or Internet is treated as dialog using VoiceXML and the transferred voice signal is processed by Speech Recognition System, and the output is returned to dialog of VoiceXML which is transferred to users. VASR system is constituted of dialog server which processes dialog, APP server for processing voice signal, and Speech Recognition System to process speech recognition. This realizes transfer method to Speech Recognition System in which voice signal is recorded using Record Tag function of VoiceXML to process voice signal in telephony environment and it is played in real time.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.1
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• pp.91-107
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• 2003

A 2-dimensional search process in the time and frequency domain is required to acquire the GPS signal, when the code phase and the carrier Doppler for the specified GPS satellite signal are unknown. This paper proposes a new scheme, called Squared-D Searching Method, which can reduce the number of carrier frequency candidates, and a new scheme, named extended Multiple Correlator(XMC), which can reduce the number of code phase candidates. The Squared-D Searching Method can take the twice of Doppler frequency, therefore it can find carrier frequency candidates. The XMC is different from the general multiple correlator in that a combined form of the locally generated codes is used for despreading. Also, this paper tries to analyze a signal detection probability of a GPS receiver under more realistic environments. The result shows that lower detection probability can be obtained when the phase differences among the codes are larger in the correlation arms of a multiple correlator. This phenomenon is not easy to explain with the previous results. And besides, the result shows that proposed acquisition schemes give better performance than a conventional acquisition scheme.

• The Journal of the Acoustical Society of Korea
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• v.16 no.2
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• pp.5-9
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• 1997

In this paper, when we use the chirp signal as input signal of ultrasonic signal system the technique for determining the bandwidth of the chirp signal that maximizes the amplitude of the compressed ultrasonic echo signal has been studied. In ultrasonic signal processing systems, the signal-to-noise ratio of the echo signal can be too low due to damping and scattering of the ultrasonic wave during transmission. Method of pulse compression using chirp signal is a means to increase the signal-to-noise ratio in ultrasonic pulse-echo systems. Simulation and experimental results showed that the output signal of ultrasonic system was increased by pulse width of chirp signal and the optimum-bandwidth of the chirp signal was 1.15 times larger than the bandwidth of the ultrasonic system.

• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.114-117
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• 2000

In this paper, we proposed robust digital image watermarking based on modulation transfer function (MTF) of human visual system (HVS). Using the proposed method, robust watermarking is possible both in common image processing operations such as cropping and lossy compression and in geometrical transforms such as rotation, scaling, and translation, because it can embed watermark and template signal maximally using MTF of HVS. Experimental results show that the proposed watermarking method is more robust to several common image processing operations and geometrical transforms.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.6
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• pp.390-394
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• 2016

This paper presents a new comparison method for haze-removal algorithms in next-generation automotive systems. Compared to previous peak signal-to-noise ratio-based comparisons, which measure similarity, the proposed modulation transfer function-based method checks sharpness to select a more suitable haze-removal algorithm for lane detection. Among the practical filtering schemes used for a haze-removal algorithm, experimental results show that Gaussian filtering effectively preserves the sharpness of road images, enhancing lane detection accuracy.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1984.04a
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• pp.29-32
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• 1984

A microprocessor for the dedicated purpose of digital filtering has been designed and constructed. A microsequencer to control the flowing of data is designed with the concept of a hardware compiler of AHPI, statements. In order to save the processing time, this system utilizes parallel data calculation method instead of the one proposed by Peled and Liu which depended on serial calculation method. The flexible program control technique has been applied to the implementation of the sepcialprocessor for the digital signal processing.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.187-188
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• 2011

Independent component analysis (ICA) is a method separating the mixture of signals into statistically and mutually independent ones. It has been applied to not only the Cocktail-party problem but also EEG analysis using the EEG waveform, digital signal processing, image processing and cognitive technique field actively. This study aims to propose a procedure to estimate the modal responses and mode shapes of a floating structure by using the ICA method from measured responses of the floating structure.

• Proceedings of the KIEE Conference
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• 1979.08a
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• pp.151-152
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• 1979

• Proceedings of the Korean Nuclear Society Conference
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• 2003.05a
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• pp.103.2-103.2
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• 2003