• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.63-69
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• 2010

Today, Internet Telephony Services based on VoIP are gaining tremendous popularity for general user. Therefore a various demands of the user keep up increase, the most important requirements of these is voice security about telephony system. 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 VPN IP-PBX for the voice security and measured conversation quality by adopting VPN IPsec based on SIP and using tunnel method in transmitting voice data to prevent eavesdrop of voice data. This VPN IP-PBX that is connected Soft-phone provide various optional services.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.12
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• pp.1011-1017
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• 2013

The human voice is the most natural means of communication. The need for speech recognition technology is increasing gradually to increase the ease of human and machine interface. The function of the avionics equipment is getting various and complicated in consequence of the growth of digital technology development, so that the load of pilots in the fighter aircraft must become increased since they don't concentrate only the attack function, but also operate the complicated avionics equipments. Accordingly, if speech recognition technology is applied to the aircraft cockpit as regards the operating the avionics equipments, pilots can spend their time and effort on the mission of fighter aircraft. In this paper, the cockpit voice command system applicable to the fighter aircraft has been developed and the function and the performance of the system verified.

• Design Convergence Study
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• v.17 no.1
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• pp.17-28
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• 2018

The manipulation of the device by hand while driving is a major factor to increase the risk of accidents, and the design of in-vehicle voice conversational interface that can compensate for this is being actively researched. The purpose of this study is to investigate the effect of the use of the barge-in function of in-vehicle voice interface on user experience. Participants were asked to carry out two tasks, one for navigation and one for music play. We conducted a survey to measure the functional user 's experience after each participant' s tasks, and measured usefulness, usability, satisfaction, and emotion as user experience factors. As a result, Barge-in has been rated as the better choice for most experience factors. There was a significant effect on usability dimension in navigation task and significant effects on usability dimension and emotional dimension in music play task. So it was found that barge-in function had a positive effect on actual user's usability and emotional dimension.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1413-1415
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• 2004

This paper proposes a SVM(Support Vector Machine) training algorithm to control a service robot with voice command. The service robot with a stereo vision system and dual manipulators of four degrees of freedom implements a User-Dependent Voice Control System. The training of SVM algorithm that is one of the statistical learning theories leads to a QP(quadratic programming) problem. In this paper, we present an efficient SVM speech recognition scheme especially based on less learning data comparing with conventional approaches. SVM discriminator decides rejection or acceptance of user's extracted voice features by the MFCC(Mel Frequency Cepstrum Coefficient). Among several SVM kernels, the exponential RBF function gives the best classification and the accurate user recognition. The numerical simulation and the experiment verified the usefulness of the proposed algorithm.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.171-174
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• 1998

본 논문에서는 음성합성(speech synthesis) 및 부호화(coding) 시스템에 있어서 음원(voice source) 모델링에 관한 문제를 살펴보고자 한다. 기존의 음원 모델링 시스템이 가지고 있는 여러 문제들을 극복하고자 기저함수(basis function) 의 가중 합(weighted-sum)으로 음원을 모델링 하는 새로운 기법을 제안하고자 한다. 제안한 방법에서는 음원 파형(voice source waveform)을 적절히 표현하기 위해서 필터뱅크(filter bank)에 기초한 기저함수의 가중 합으로 나타낸다. 다양한 음원 특성을 효과적으로 나타내는 음원 파라미터를 구하기 위하여 EM(estimate maximize)에 기초한 구조에 관해 조사한다. 제안한 방법을 이용하여 다양한 유성음에 대해 실험을 수행하였다. 실험결과 제안한 추정(estimation) 방법 및 모델링 방법을 이용하면 기존의 방법에 비해 더 정확한 음원 파형을 추정할 수 있고, 다양한 음원 특성을 나타낼 수 있다. 또한 음성합성 및 부호화에서도 음성품질(voice quality)를 개선시킬 수 있으리라 기대된다.

• Journal of Korea Multimedia Society
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• v.17 no.3
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• pp.294-299
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• 2014

In this paper, we propose a novel algorithm to improve the performance of a voice activity detection(VAD) which is based on the generalized normal-Laplace(GNL) distribution. In our algorithm, the probability density function(PDF) of the noisy speech signal is represented by the GNL distribution and the variance of the speech and noise of GNL distribution are estimated using higher order moments. Experimental results show that the proposed algorithm yields better results compared to the conventional VAD algorithms.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.4
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• pp.255-261
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• 2011

In this paper, we propose a security-enhanced storing method for the voice data obtained during the flight. When an emergency occurs during flight, the flight data in the storage device such as DTS or Blackbox can be exposed to antagonist or enemy. Currently, zeroize function is embedded in these devices in order to prevent this situation. However, this could not be operated if the system is malfunctioned or the pilot is wounded in the emergency. In order to solve this problem, the voice data compressed by the ADPCM is encrypted in the proposed method composed of the AES algorithm and a reordering method. The simulation results show that the security for the voice date is further enhanced due to the proposed method.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.33 no.1
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• pp.7-12
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• 2022

Tracheostomy refers to a surgical incision created in the neck to allow direct air entry into the trachea bypassing the upper respiratory tract including the oral and nasal cavities. Normal vocalization and swallowing are limited immediately postoperatively; however, gradual recovery of vocalization and swallowing function can be initiated, following improvement in the causative condition that necessitated the tracheostomy. Duration of the tracheostomy depends upon the patient's condition, and the degree of vocalization and swallowing function recovery after tracheostomy tube removal varies widely across patients. In this review, we investigated the changes associated with vocalization and swallowing function in patients who underwent tracheostomy and have discussed the various approaches and voice rehabilitation treatments to aid with normal recovery.

• Journal of Korea Multimedia Society
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• v.23 no.11
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• pp.1418-1427
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• 2020

The web has become indispensable in all of our daily lives. We communicate, study and get information with others through the web. This behavior also continues in the smart phone environment. The biggest problem is that the small display screen of a smart phone degrades the accuracy in selecting or manipulating content for people with low vision. To compensate for this, voice guidance services that combine touch and voice, such as VoiceOver and Talkback, are currently provided to smart phone devices. However, restrictions arise in GUI, TTS control problems, and content expansion and selection. In addition, unnecessary content is also output by voice, which causes fatigue for low vision people to use. In this study, we propose a mobile web browser interface that selects and enlarges a desired area from web browsers and contents, or outputs it as a voice so that people with low vision can easily use the mobile web browser. In this paper, we propose a context selective focusing function that enables selection for each element of web content. In addition, we intend to develop a mobile voice web browser that can enlarge the selected content or output it by voice.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.28 no.2
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• pp.112-117
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• 2017

Background and Objectives : The purpose of this study was to classify patients with unilateral vocal fold paralysis according to their fixed location and to analysis the effects of two treatment methods by early voice therapy and injection laryngoplasty. Materials and Methods : Twenty patients who were classified as full abduction and slight abduction according to the position of paralysis were treated injection laryngoplasy, and 23 patients were treated by voice therapy. Twenty patients were treated injection laryngoplasy and 23 patients were treated voice therapy. Results were evaluated by acoustic analysis, electroglottography, cepstrum analysis before and after therapy. The voice therapy was conducted by improving the larynx movement and glottal contact, whilst removing hypertension of the supraglottic and use the breathing. Results : Significant improvement was found in the acoustic parameter, cepstrum parameter, and EGG before and after treatment in both groups. There was no significant difference between the two groups when compared before and after treatment to compare the effects of injection laryngoplasty and voice therapy. Conclusion : The initial treatments for unilateral vocal cord paralysis are injection laryngoplasty and voice therapy. however, there is no precise standard about which method should be applied first. Therefore, in this study, we tried to classify patients according to their paralysis position and then apply two methods. The results of this study suggest that voice therapy and Injection laryngoplasty at the initial stage is a very useful method to improve voice quality of vocal fold paralysis and improve laryngeal function.