• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.21 no.1
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• pp.57-60
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• 2010

Spasmodic dysphonia is a focal dystonia of the larynx and breathy voice is a typical sign of abductor spasmodic dysphonia. A group of patients with abductor spasmodic dysphonia have a number of acoustic characteristics including abnormal fundamental frequency fluctuations and abnormally long word duration. We report a abductor spasmodic dysphonia case have enlongated voice onset time voiceless consonants and breathy voice in wide band spectrogram. The patient have the acoustic characteristics only in telephone speaking at work time. We treated the patient with anticholinergic and anticonvulsant drug and supplementary voice therapy. The breathy voice and enlongated VOT were disappeared after those treatment.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.25-28
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• 2002

Voice activity detection is important Problem in the speech recognition and communication. This paper introduces feature parameter which is reconstructed by the spectral entropy of information theory for the robust voice activity detection in the noise environment, analyzes and compares it with the energy method of voice activity detection and performance. In experiment, we confirmed that the spectral entropy is more feature parameter than the energy method for the robust voice activity detection in the various noise environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.1 no.2
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• pp.137-143
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• 1997

From now on, the network is being developed into PSTN(public switched telephone network) and PDN(public data network), that is depend on the form of data. The former one pursues sending voice, and the latter one pursues sending data. But it causes big loss of the economy and efficiency. So, ISDN, processing voice and data at same time, gives a big profit to user. To enlarge the ISDN at the narrow area, it is necessary that study to send the mixture form of voice and data in LAN environment. So, this paper proposes the algorithm about the mixture form of voice and data in ethernet and token-ring. that is widely used in these days.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.141-148
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• 2014

Voice is the most common means for communication, but some people have difficulties in generating voice due to their congenital or acquired disorders. Individuals with speech disorders might lose their speaking ability due to hearing impairment, encephalopathy or cerebral palsy accompanied by motor skill impairments, or autism caused by mental problems. However, they have needs for communication, so some of them use various types of AAC (Augmentative & Alternative Communication) devices in order to meet their communication needs. In this paper, a mobile application for literate people having speech disorder was designed and implemented by developing accurate and fast sentence-completion functions for efficient user interaction. From a user study and the previous study on Korean text-based communication for adults having difficulty in speech communication, we identified functionality and usability requirements. Specifically, the user interface with scanning features was designed by considering the users' motor skills in using the touch-screen of a mobile device. Finally, we conducted the usability test for the application. The results of the usability test show that the application is easy to learn and efficient to use in communication with people with speech disorders.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.489-489
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• 2006

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.73-80
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• 2009

Although it is relatively difficult to eavesdrop the commonly used PSTN in that it is connected with direct circuit, it is difficult to ensure the secret of call on Internet because many users can connect to the Internet at the same time. However, it is needed to ensure secret of voice call in a special situation. Due to the fact that many users can connect to the internet at the same time, VoIP can always be in a defenseless state by hackers. Therefore, in this paper, we have developed the increased voice security internet telephone terminal and measured conversation quality by adopting VPN PPTP based on SIP and using tunnel method in transmitting voice data to prevent eavesdrop of internet telephone.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1327-1332
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• 2015

In this paper, we studied several aspects that affect the quality of VoIP using WiFi network. It's clear that the background data traffic within an AP, the end-to-end delay and the traffic loss of TCP/IP network gives serious effects on the voice quality. A kind of access control for the VoIP connection within an AP should be done for the acceptable voice quality.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.11
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• pp.2405-2410
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• 2012

The 4th generation mobile communication system, LTE, does not support an additional core network to provide voice service, and it is merged into a packet network based on all IP. Although Voice service over LTE can be supported by VoIP, it will be provided by the existing 3G networks because of the discontinuity of LTE coverage. However, it is inevitable to adopt VoIP over LTE to provide high quality voice service. In this paper, we investigate the capacity of VoIP over LTE. Our results indicate that spectral efficiency can be significantly improved as channel bandwidth increases in terms of VoLTE capacity. In addition, we can achieve higher VoLTE capacity without decreasing control channel capacity.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.89-94
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• 2015

FMS which has a concept that wireless terminal can replace wire terminal services is a technologies that is can provide service costs same as wire terminal in the special zone. Enterprise type of FMC that is developed making up for the weak point is must have to improve voice quality and FMC performance in the soft phone. This paper measure voice quality based on the one way of the total estimated delay time of FMC to carry out IMS services between IP-PBX and FMC soft-phone to operate it's controller optimally and put forward evidence to be in 120ms and 150ms in the VoIP FMC voice quality. To measure FMC performances in four categories evaluated trials and prove its performances.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.199-204
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• 2019

This paper introduces smart mirror that provides the contents needed for an individual's daily life. When a command that is designated as voice recognition is entered, Smart Mirror is produced that outputs desired contents from a display. The contents of the current smart mirror include time, weather, subway information, schedule and photography. Smart mirror sold for commercial private households is difficult to distribute due to high prices, but the smart mirror production presented in this paper can lower the manufacturing cost and can be more easily used by voice recognition.