• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.774-776
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• 2012

CCTV(Closed Circuit Television : 폐쇄회로텔레비전)는 산업, 교육, 교통관제, 범죄예방 등의 다양한 목적으로 이미 많은 분야에 활용되고 있다. CCTV의 사용목적이 다양화되면서 CCTV로부터 촬영된 영상데이터는 굉장히 중요한 자료로 사용된다. CCTV는 영상 및 음성 데이터를 특정 사용자에게 전송하는 시스템으로 수신대상 이외에는 수신할 수 없도록 구성되어 있다. 이러한 CCTV 운영 시스템은 제 3자가 폐쇄회로 내부에 접근한 경우에 대한 보안이 취약하다. 즉 제 3자가 폐쇄회로 내에 접근하게 되면 데이터 포획, 데이터 위 변조가 쉽게 이루어 질 수 있다. 본 논문에서는 폐쇄회로 내에서 인가되지 않은 기기 및 공격자에 의한 데이터 포획, 데이터 위 변조 방지를 위한 프로토콜을 제안한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.150-155
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• 2006

Speech intelligibility is investigated on a conference room-window glass coupled system. Using MLS(Maximum Length Sequency) signal as a sound source, acceleration and velocity responses of the window glass are measured by accelerometer and laser doppler vibrometer. MTF(Modulation Transfer Function) is used to identify the speech transmission characteristics of the room and window system. STI(Speech Transmission Index) is calculated by using MTF and speech intelligibility of the room and the window glass is estimated. Speech intelligibilities by the acceleration signal and the velocity signal are compared and the possibility of the wiretapping is investigated. Finally, intelligibility of the conversation sound is examined by the subjective test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.649-654
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• 2007

Eavesdropping prevention performance is evaluated on a commercial window shaker, which is used to prevent a glass window from eavesdropping. Speech transmission index (STI) is introduced in order to estimate quantitatively the speech intelligibility of the sound detected on the glass window. Objective test by IEC standard using modulation transfer function (MTF) is performed to determine STI. Using Maximum Length Sequency (MLS) signal as a sound source, MTF is measured by accelerometers and laser doppler vibrometer. STI under different level of disturbing wave are compared to confirm the disturbing effect on the speech intelligibility.

• Phonetics and Speech Sciences
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• v.7 no.1
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• pp.47-55
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• 2015

This study examined whether speech acceptability was changed under various conditions of prosodic manipulations. Both speech rate and voice loudness reportedly are associated with acceptability and intelligibility. Speech samples by twelve speakers with mild dysarthria were recorded. Speech rate and loudness changes were made by digitally manipulating habitual sentences. 3 different loudness levels (70, 75, & 80dB) and 4 different speech rates (normal, 20% rapidly, 20% slowly, & 40% slowly) were presented to 12 SLPs (speech language pathologists). SLPs evaluated sentence acceptability by 7-point Likert scale. Repeated ANOVA were conducted to determine if the prosodic type of resynthesized cue resulted in a significant change in speech acceptability. A faster speech rate (20% rapidly) rather than habitual and slower rates (20%, 40% slowly) resulted in significant improvement in acceptability ratings (p <.001). An increased vocal loudness (up to 80dB) resulted in significant improvement in acceptability ratings (p <.05). Speech rate and loudness changes in the prosodic properties of speech may contribute to improved acceptability.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.551-556
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• 2008

Possibility of the remote eavesdropping through window glass is investigated using a laser sensor. Various thicknesses and types of glass windows are excited by maximum length sequency (MLS) signal and the vibration sound is detected by a laser doppler vibrometer. Intelligibility of the detected sound is evaluated using the speech transmission index (STI), which is based on the modulation transfer function (MTF). In order to identify the disturbing effect, different level of disturbing wave is generated by an outside speaker and a window shaker attached on the glass window. On the different thickness of glass windows, decrease effect of the speech intelligibility is analysed.

• Phonetics and Speech Sciences
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• v.4 no.4
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• pp.109-115
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• 2012

This paper mainly aims to investigate how differently choral speech and altered auditory feedback (i.e., delayed auditory feedback, frequency-altered feedback) enhance speech fluency during sentence reading. To do this, a stuttering reduction rate was used and measured how much stuttering in frequency was reduced during each of the fluency enhancing conditions (i.e, typical choral reading, DAF, FAF) relative to typical solo reading. The results showed that stuttering frequency was reduced in the three fluency enhancing conditions and the highest mean value in stuttering reduction rate was observed during typical choral reading. Some discussion was provided in relation to the stuttering reduction rate observed during typical choral reading and its further speculation.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.55-60
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• 2007

Possibility of the eavesdropping is investigated on a conference room-glass window coupled system. Speech intelligibility analysis is performed on the eavesdropping sound of the glass window. Using MLS(Maximum Length Sequency) signal as a sound source, acceleration and velocity responses of the glass window are measured by accelerometer and laser doppler vibrometer. MTF(Modulation Transfer Function) is used to identify the speech transmission characteristics of the room and window system. STI(Speech Transmission Index) is calculated by using MTF and speech intelligibility of the vibration sound is estimated. Speech intelligibilities by the acceleration signal and the velocity signal are compared.

• Phonetics and Speech Sciences
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• v.6 no.2
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• pp.81-88
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• 2014

The normal aging process on speech production and these changes are perceived by listeners. This study examined whether age perception changed under various conditions of prosodic manipulations in normal listeners, comparing the prosodic changes according to age and sex in adulthood. The older and younger voices were resynthesized by manipulation of the speaking rate and pitch to shift the perceived age of the groups toward each other. Two-way repeated ANOVA were conducted to determine if the prosodic type of resynthesized cue resulted in a significant shift in perceived age of young and old voices. The manipulation of the speaking rate resulted in a significant shift in perceived age for the older and younger groups. A significant shift in age estimates was not observed for the younger male group when pitch was manipulated. There were significant gender-by-age group interactions for prosodic manipulation type. Age-related changes in the prosodic properties of speech may ultimately influence speech perception.

• Journal of Broadcast Engineering
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• v.13 no.5
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• pp.612-621
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• 2008

Due to the various constraints such as feasible size of data payload and low transmission power, no technical specifications on the voice communication are included in the Zigbee standard. In this paper, a voice coding technique for application to the IEEE 802.15.4 standard, which is the basis of Zigbee communication, is presented. Here, both high compression and good waveform recovery are essential. To meet those requirements, a multi-stage discrete wavelet transform (DWT) block and a binary coding block consisting of two different pulse-code modulations are exploited. Theoretical analysis and simulation results in an indoor wireless channel show that the voice coder with 2-stage DWT is most appropriate from the viewpoint of compression and waveform recovery. When the line-of-sight component is dominant, the voice coding scheme has good recovery capability even in the moderate signal-to-noise power ratios. Hence, it is considered that the presented scheme will be a technical reference for the future recommendation of voice communication exploiting Zigbee.

• Proceedings of the Optical Society of Korea Conference
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• 1991.07a
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• pp.55-59
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• 1991

신경회로망은 뒤뇌의 신경조직이 갖는 병렬적이며 분산적인 정보처리 능력을 흉내낸 인공적인 회로망이다. 이러한 신경회로망을 영상인식, 음성인식, 적응제어 및 최적화등에 응용할 경우 지금까지 얻지 못하였던 우수한 여러 가지 특성을 얻을수 있음을 알려짐에 따라 신경회로망을 구체적으로 구현하고자 하는 연구가 활발히 이루어지고 있다. 본 고에서는 신경소자간의 연결세기의 변조에 의한 학습 원리를 설명하고 광전기적인 그현방법에 대해서 몇 개의 예를 들어 설명하고 그 발전 가능성에 대하여 기술하였다.