• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.11
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• pp.184-193
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• 1998

In this paper, a real-time acoustic echo canceller is implemented using only PC's CPU without extra help from a DSP chip. The adaptive digital filter is designed efficiently so that it can be implemented in real-time and has a proper cancellation performance. It is proposed that a new double talk detector consumes a small computational complexity and guarantees the fast detection and robust operation. The real-time acoustic echo canceller consists of the full-duplex sound card and 166 MHz Pentium PC, and requires less than 10% CPU time.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.4
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• pp.17-23
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• 1999

This paper described a security system using text-independent speaker recognition algorithm. Security system is based on PIC16F84 and sound card. Speaker recognition algorithm applied a k-means based model and weighted cepstrum for speech features. As the experimental results, recognition rate of the training data is 100%, non-training data is 99%. Also false rejection rate is 1%, false acceptance rate is 0% and verification mean error rate is 0.5% for registered 5 persons.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.717-722
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• 2006

경제지표, 주식시세, 전자상거래 등 시각적으로 제공되는 정보 중에 정확한 숫자가 중요한 정보인 경우도 있지만 2 차 정보로서 변화의 추세나 패턴이 중요한 경우도 있다. 주식을 포함한 유가증권이나 선물거래의 경우 주로 미국식 봉차트를 사용하는데 개인투자자가 늘고 있는 우리나라 실정으로 볼때 식음을 전폐하고 전광판에 매달리는 문제점이 지적되고 있고, 전문투자자들도 시각정보를 놓치지 않기 위해 일상 업무에 소홀해지는 경우가 많다. 이러한 경우 음향정보도 함께 제공한다면 인간은 다양한 감각기관을 가지고 있기 때문에 시각정보를 주로 이용하다가도 잠시 휴식을 취하거나 다른 용무가 있을 때 청각정보를 보완적으로 사용하여 스트레스를 줄일 수 있고 명철한 판단력을 유지할 수 있으며, 경우에 따라서는 음향정보가 상황판단을 위해 더욱 효과적일 수도 있을 것으로 본다. 음향정보가 시각정보를 대체하기 보다는 2 차 정보로서 상호보완성이 목적이라면 정확한 숫자의 표현보다는 거래패턴 등을 음악적으로 표현하여 음악 감상의 기능까지 갖춘다면 시각정보와는 차별화된 음향정보의 독자성을 찾을 수 있다. 간혹 종목별 등락을 읽어주거나 중요한 매매시점에 신호음을 내는 청각적인 방법이 사용되기도 하지만 상당히 제한적이고 단순한 상태이다. 그러므로 본 연구의 진정한 개발목적은 정보성 이외에 예술적 표현을 융합하는 것이며, 시각장애인이나 네트워크 환경이 열악한 사람들도 주식투자에 있어서 평등성을 보장하여 건전한 투자문화를 형성하기 위함이다. 실시간 거래정보를 음악적으로 표현하여 업무를 보면서도 들려오는 음악을 통해 거래상황을 파악할 수 있는 연구방법으로 거래빈도는 음의 빠르기로, 거래가는 음의 높낮이, 거래량은 음의 세기, 종목은 악기의 음색으로 표현하였으며, 컴퓨터에 내장된 사운드카드를 통해 소리를 들을 수 있도록 MIDI 데이터로 변환하였다. 통계정보는 주로 한국증권선물거래소(KRX: The Korea Exchange)에서 발췌하였으며, 시뮬레이션을 위한 프로그래밍 언어로는 Cycling74 의 Max/MSP 를 사용하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1229-1236
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• 2009

Puretone audiometer, which is a machine used for measuring the minimum hearing threshold, can be cost-effectively implemented using computer with sound card and software. In this paper, we describe a puretone audiometer which has been designed and implemented based on a general PC with sound card. It supports air conduction and bone conduction test taking with automatic masking. It also provides multiple modes consisted of self-test, auto-test and manual test mode. Such multiple modes makes it possible to use in various environments like as home and/or hospital. Through measure of waveform of output voltage and sound pressure, we verified that puretone audiometer of this paper properly operates.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.688-694
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• 2009

A spray-type cleaning agent in utilizing dust-remover on PCB was chosen to study the cleanliness test and efficiency. In order to choose alternative environmental-friendly cleaning agents, it is important that the systematic selection procedures should be introduced and applied through the evaluation of their cleaning ability, environmental characteristics, and economical factors, and that the objective and effective evaluation methods of cleanliness should be established for the industry. A novel cleaning evaluation method with scanning electron microscopy/energy-dispersive X-ray analysis of surface observation evaluation method and an infra-red thermography camera(THERMOVISION A20 model) was studied in this work. The sound card(CT-2770 model) cut by $2{\times}2cm$ size was used as a part, and before and after the spray cleaning, the cleanliness was observed by the image analyzer of SEM and further the removal efficiency of dust was quantitatively evaluated by the component analysis of EDX. For the parts of P4TE model motherboard and IPC-A-36 PCB plate, before and after the spray cleaning, temperature differences were measured and compared at room temperature and 50 oven temperature by an infra-red thermography camera in the contaminants of dust and iron powder.

• The Journal of the Acoustical Society of Korea
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• v.18 no.2
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• pp.3-10
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• 1999

This paper describes the development and evaluation of a Korean address input system employing automatic speech recognition technique as user interface for input Korean address. Address consists of cities, provinces and counties. The system works on a window 95 environment of personal computer with built-in soundcard. In the speech recognition part, the Continuous density Hidden Markov Model(CHMM) for making phoneme like units(PLUs) and One Pass Dynamic Programming(OPDP) algorithm is used for recognition. For address recognition, Finite State Automata(FSA) suitable for Korean address structure is constructed. To achieve an acceptable performance against the variation of speakers, microphones, and environmental noises, Maximum a posteriori(MAP) estimation is implemented in adaptation. And to improve the recognition speed, fast search method using variable pruning threshold is newly proposed. In the evaluation tests conducted for the 100 connected words uttered by 3 males the system showed above average 96.0% of recognition accuracy for connected words after adaption and recognition speed within 2 seconds, showing the effectiveness of the system.

• The Journal of the Korea Contents Association
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• v.18 no.1
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• pp.587-595
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• 2018

This research aims to analyze the importance-performance among multiplex cinema selection attributes. Therefore, we collected data for visitors who visited the multiplex cinema and want to watch movies. Of the various multiplex cinema selection attributes, four factors were deduced that includes: major services, human services, physical environment, auxiliary services using exploratory factor analysis. In the quadrant I, the area of 'Concentrate Here' was 'diversity of screening time', 'diversity of movie genre', 'convenience of mobile app use', 'size and convenience of parking facility'. In the quadrant II, 'Keep up the Good Work' area was 'convenience of website booking', 'discounts through card partnerships', 'employee friendliness', 'accurate employee information delivery', 'comfortable seating', 'screen size', 'cinematic sound quality', and 'convenience of traffic' etc. The quadrant III, 'Low Priority' appeared to be 'membership system', 'tidiness of staff attire', 'resting space for waiting time', 'accessibility to the neighboring area', 'diversity of the snack corner', and 'overall cleanliness' etc. The quadrant IV, 'Possible Overkill' was 'appropriateness of the auditorium temperature' and 'service proficiency'.

• Journal of the Korea Society of Computer and Information
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• v.16 no.7
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• pp.77-84
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• 2011

The B$\'{e}$k$\'{e}$syaudiometry makes possible to determine not only hearing threshold but also assumption of recruit phenomenon. Additionally, it is helpful to investigate cause of hearing loss. In this paper, we describe a development of PC based B$\'{e}$k$\'{e}$syaudiometer which complies with ANSI standards and provides cost competitiveness. It dynamically produces sound having required frequency and sound pressure level and supports audiogram interface showing test result at realtime. To provide ANSI defined maximum sound level, an amplifier has been developed. We have been verified our system whether it conforms to ANSI standards.

• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.1-7
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• 2008

The paper is to solve the problem of existing sound system, which has difficulties of system organization and the increase of additional install cost and unfriendly interior. To solve the existing system, we drew the new sound system based on PLC and studied it. A transmitter and a receiver were designed using the PLC chip INT5500CS. Sound system was configured with a CD player that sound signals are sent from the transmitter and a speaker connected to the receiver. For analysis of characteristics of this system, a USBPre external sound card and Smaart Live 5 which is a PC-based sound measuring program were added. As a result of our experiment, the measured signal level is $2{\sim}3$[dB] lower than reference signal, latency is 16.69[ms] and the specific character of coherency is bad in high frequency band. Otherwise, this system transmits and receives signals over 90[%] in good condition as a result of measuring pink noise, frequency(1kHz), and phase, magnitude. In view of the result so far achieved, the system designed our team has excellent performance, it resolves defect of existing audio signal transmition system.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.343-349
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• 2004

Electroglottograph(EGG) is a signal recorded from the vocal cord vibration by measuring electrical impedance across the vocal folds through the neck skin. The purpose of this study was to develop EGG system and to evaluate possibility for the application on speech analysis and laryngeal disease diagnosis. EGG system was composed of two pairs of ring electrodes, tuned amplifier, phase sensitive detector, low pass filter, and auto-gain controller. It was designed to extract electric impedance after detecting by amplitude modulation method with 2.7MHz carrier signal. Extracted signals were transmitted through line-in of PC sound card, sampled and quantized. Closed Quotient(CQ), Speed Quotient(SQ), Speed Index(SI), fundamental frequency of vocal cord vibration(F0), pitch variability of vocal fold vibration (Jitter), and peak-to-peak amplitude variability of vocal fold vibration(Shimmer) were analyzed as EGG parameters. Experimental results were as follows: the faster vocal fold vibration, the higher values in CQ parameter and the lower values in SQ and SI parameters. EGG and speech signals had the same fundamental frequency. CQ, SQ, and SI were significantly different between normal subjects and patients with laryngeal cancer. These results suggest that it is possible to implement portable EGG system to monitor the function of vocal cord and to test functional changes of the glottis.