• 스마트미디어저널
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• 제12권2호
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• pp.56-65
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• 2023

뉴스와 취재 프로그램 같은 방송에서는 제보자의 신원 보호를 위해 음성을 변조한다. 음성 변조 방법으로 피치(pitch)를 조절하는 방법이 가장 많이 사용되는데, 이 방법은 피치를 재조절하는 방식으로 쉽게 원본 음성과 유사하게 음성 복원이 가능하다. 따라서 방송 음성 변조 방법은 화자의 신원 보호를 제대로 해줄 수 없고 보안상 취약하기 때문에 이를 대체하기 위한 새로운 음성 변조 방법이 필요하다. 본 논문에서는 Voice Privacy Challenge에서 비식별화 성능이 검증된 Lightweight 음성 비식별화 모델을 성능 비교 모델로 사용하여 피치 조절을 사용한 방송 음성변조 방법과 음성 비식별화 성능 비교 실험 및 평가를 진행한다. Lightweight 음성 비식별화 모델의 6가지 변조 방법 중 비식별화 성능이 좋은 3가지 변조 방법 McAdams, Resampling, Vocal Tract Length Normalization(VTLN)을 사용하였으며 한국어 음성에 대한 비식별화 성능을 비교하기 위해 휴먼 테스트와 EER(Equal Error Rate) 테스트를 진행하였다. 실험 결과로 휴먼 테스트와 EER 테스트 모두 VTLN 변조 방법이 방송 변조보다 더 높은 비식별화 성능을 보였다. 결과적으로 한국어 음성에 대해 Lightweight 모델의 변조 방법은 충분한 비식별화 성능을 가지고 있으며 보안상 취약한 방송 음성 변조를 대체할 수 있을 것이다.

• 음성과학
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• 제11권2호
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• pp.165-177
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• 2004

Western singers voice have been studied in music science since the early 20th century. However, Korean traditional singers voice have not yet been studied scientifically. This study is to find the physiological and acoustic characteristics of Pansori singers voices. Western singers participated for comparative purposes. Ten western singers and ten Pansori singers participated in this study. The subjects spoke and sung seven simple vowels /a, e, i, o, u, c, w/. An analysis of Glottal image was done by Scope View and acoustic characteristics of speech and singing voice were analyzed by CSL. The results are as follows: (1) Glottal gestures of Pansori singers showed asymmetric vocal folds. (2) Singing vowel formants of Pansori singers showed breathiness based on Spectrogram. (3) Music formant of western singers appeared in around 3kHz area, however, Pansori singers formant appeared in low frequency area. Modulation of vibrato showed 6 frequency per sec in case of western singers. Pansori singers showed no deep modulation of vibrato on spectrogram.

• 한국음향학회지
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• 제26권7호
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• pp.366-374
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• 2007

수중에서 무선통신이 기존에는 초음파를 이용한 단거리통신에 국한되었으나 최근 고주파를 이용한 장거리 통신의 필요성이 증가되고 음성뿐만이 아니라 각종 데이터나 고화질 영상자료의 송수신 수요가 늘어나고 있다. 본 연구에서는 수중에서 디지털 변조방식의 차이에 따라 실제 수중통신에 미치는 영향에 대하여 연구하였다. 모의 환경 하에서 PSK기반의 변조방식(BPSK, QPSK, MSK, GMSK)에 대한 시뮬레이션을 통해 실험한 결과 GMSK만이 큰 차이를 보였다. 위 결과를 바탕으로 SNR을 35dB이하로 하고 부산 남방에 위치한 207-선(한국해양자료센타)의 15Km 구간을 모의하여 음성통신과 영상자료를 전송실험한 결과 음성통신시($10^{-2}$BER, 채널용량 1Kbps기준)는 약 8Km의 거리 차이를, 그리고 영상자료($3{\times}10^5$ 화소, 화소 당 정보량 4bit) 전송시는 BPSK, QPSK, MSK 는 60Kbps, GMSK는 45Kbps의 전송율을 확보하여 약 7초의 전송시간 차이가 생김을 확인하였다.

• 한국기계가공학회지
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• 제6권2호
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• pp.59-66
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• 2007

Voice coil actuator is used linear motion system that requires precision positioning control. In order to control precision positioning of voice coil actuator, relation model between duty ratio and moving displacement of voice coil actuator is needed. This paper present a duty ratio - displacement model in PWM control of voice coil actuator. Transfer function of voice coil actuator is obtained by combining voice coil motor's equation of motion with the equation of circuit and characteristic of voice coil motor. Consider to initial condition of velocity and current, transfer function is transformed mathematical model. The induced model can predict output displacement, velocity and current according to duty ratio and amplitude. The model is verified by experimental tests such as velocity and displacement response of voice coil motor. Simulated results have tracking errors of less than 10 percent of experimental results.

• 대한음성학회지:말소리
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• 제51호
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• pp.1-16
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• 2004

The aim of this paper is to analyze vowels in voice imitation and disguised voice, and to find the invariable phonetic features of the speaker. In this paper we examined the formants of monophthongs /a, u, i, o, {$\omega},{\;}{\varepsilon},{\;}{\Lambda}$/. The results of the present are as follows : $\circled1$ Speakers change their vocal tract features. $\circled2$ Vowels /a, ${\varepsilon}$, i/ appear to be proper for speaker recognition since they show invariable acoustic feature during voice modulation. $\circled3$ F1 does not change easily compared to higher formants. $\circled4$ F3-F2 appears to be constituent for a speaker identification in vowel /a/ and /$\varepsilon$/, and F4-F2 in vowel /i/. $\circled5$ Resulting of F-ratio, differences of each formants were more useful than individual formant of a vowel to speaker recognition.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.57-58
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• 2006

A Simulation model is developed to minimize the path tracking errors when the non-circular cutting is done by a VCM(voice coil motor) driven tool. The relationship between PWM(Pulse Width Modulation) duty ratio and velocity of voice coil motor is theoretically derived from combining the circuit equation for the coils and the motion equation for the magnetic rod of the voice coil motor. The path tracking errors are showed differently according to the rotational speed, the number of segments and the control period in digital control. Given a required accuracy in the non-circular cutting, the optimal values for those parameters are determined based on the developed simulation model.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1658-1660
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• 2000

Simple signs were usually exchanged as the means of underwater communications. As people recently, need more informations for underwater activities, necessities of underwater communication systems exchanging hunman voice are increased. The purpose of this paper is understanding the ordinary characteristics of underwater communication and investigating the necessary conditions for a good underwater communication system by making a basic communication module. The experiment is achieved by applying AM (Amplitude Modulation) which is mainly used for the underwater communication systems and using common ultrasonic transducers. Ultrasonic transducers usually have narrow bandwidth for transducing electrical energy to mechanical energy. For improvement of sound reconstruction, transducers need more bandwidth which covers voice's frequency range, and goof linearity characteristics in this frequency range. As underwater transmissions have many factors to distort signals. Amplitude Modulation is not a proper way for underwater communications. Using digital signal by sampling human voice should be a good way for this systems, because digital communication simplify transmitting signals.

• 한국군사과학기술학회지
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• 제14권2호
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• pp.222-231
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• 2011

In this paper, we have proposed a method which can make it possible to stably transmit and receive data like the ARC-164 radio frequency hopping environment as a S/W packet modem with PSK modulation. This is a method that the S/W packet modem with PSK digital modulation and the use of PC sound cards change over from data to voice signals and then transmit/receive data. We confirmed not only that it is possible to solve the slow speed communication with the use of sending data through multi-channels and PSK modulation that has the ability to methodically improve transmission rates, but also that it is possible to send the state of frequency hopping stably. In conclusion, we've confirmed both tactical values that though the transmission rate may be a tad slow, a state of frequency hopping of more than 94% confidence plus voice and data can be sent via radio at the same time. In this paper, the proposed S/W packet modem is only an implemented S/W component, so when we apply it to aircraft that we don't consider EMC problems with, then we have the advantage of a wider use of conventional UHF/VHF/HF radio that is possible to voice communication. If we recognize these operational requirements, we can apply for a lot of field equipment efficiently.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(1)
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• pp.77-80
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• 2000

In this paper, we implemented the voice modem using the multicarrier DS-CDMA in powerline channels. Both TMS320C5402 of Texas Instrument and FPGA FLEX 10K EPF10K100ARC240 of ALTERA are used to realize the proposed system. For robustness in the powerline channel, we used multicarrier DS-CDMA modulation, convolutional encoding/Viterbi decoding, and interleaving. Finally, we showed satisfactory performance in the laboratory experiment.

• 음성과학
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• 제12권3호
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• pp.19-33
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• 2005

Tremor is a main factor of parkinsonism. Voice tremor may be the first, later or the only symptom of a neurological disease and its frequency, amplitude, and regularity may differ among the diseases of different neural subsystems. Differential diagnosis between idiopathic Parkinson's disease (IPD) and multiple system atrophy (MSA) has been difficult. This study included three groups: (1) 6 IPD patients; (2) 6 MSA patients; and (3) 20 ageand sex-matched normal controls. The MDVP (Multidimensional Voice Program) was used to analyze the sustained /a/phonation. The results were as follows: (1) frequency perturbation parameters (jitter, sPPQ, Vf0) and FTRI of tremor parameter of two patient groups were statistically different from those of the controls (p < .01); (2) measures were higher in short-term and long-term f0 and amplitude perturbation in MSA than IPD; (3) however, any acoustic parameters between IPD and MSA were not statistically different; except for the rate of frequency tremor, 4$\sim$5 Hz in IPD, 5$\sim$11 Hz in MSA and (4) the pattern of regularity for voice tremor through histogram indicated that amplitude of IPD was irregular while both f0 and amplitude of MSA were irregular. In conclusion, F0, rate of frequency tremor, and pattern of f0 regularity may be predictors for differential diagnosis. These findings might signify that voice tremor of parkinsonism was resulted from modulation of f0.