• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2002.11a
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• pp.229-234
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• 2002

OFDM(Orthogonal Frequency Division Multiplexing) 전송방식은 SCM(Single Carrier Modulation)에 비해 우수한 여러 가지 장점들을 가지며, 방송시스템들 중 Eureka 147 DAB(Digital Audio Broadcasting) 시스템에 가장 먼저 채택되었다. 그러나 OFDM 신호의 높은 PAPR(Peak-to-Average Power Ratio) 특성은 D/A, A/D 변환기의 복잡도를 높이고, 고출력 증폭기의 효율성을 감소시키는 원인이 된다. 이를 개선하기 위한 방법 중에, SDT(Signal Distortion Technique)는 전송시스템의 규격 및 수신기의 변경 없이도 적용 가능하다는 장점을 갖는다. 본 논문에서는 SDT에 속하는 companding 기법을 Eureka 147 DAB 시스템에 적용하여 PAPR 개선정도에 따른 시스템의 요구 $E_2/N_0$ 및 out-of-band의 PSD 열화 정도를 분석하였으며, 이를 clipping 기법의 성능과 비교하였다. 모의실험 결과, $\mu$값이 2인 경우, companding 기법이 PAPR, $E_2/N_0$, out-of-band의 PSD 특성 모두에서 clipping 기법에 비해 우수한 성능을 나타냈다. 또한 $\mu$ 값을 고정시킨 경우, 정규화 값이 증가할수록 신호왜곡 정도가 줄어들어 $E_2/N_0$, out-of-band의 PSD 성능개선 정도는 증가하지만, 이와는 반대로 PAPR 값은 개선 정도가 줄어들었다.

• Journal of Sensor Science and Technology
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• v.22 no.2
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• pp.156-161
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• 2013

This study was aimed to implement the electroglottography (EGG) system for analyzing fundamental frequency of the phonation. EGG was recorded from the conductance between ring electrodes attached to the neck skin area near thyroid cartilage with high frequency carrier electric signals during vocalization, and voice signal was recorded with microphone simultaneously. EGG and voice signals were transmitted to the audio port in PC and recorded with stereo sound recording program. From the digitized data, several parameters such as pitch, jitter, shimmer, CQ and SQ were analyzed from the vowel sounds. For the voice training, sound fundamental frequency was displayed during the vocalization and singing a song using pitches analyzed from the EGG. The system implemented in this study could be used for vocal exercise.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.3
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• pp.206-214
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• 2005

In these days the virtual reality technology has been applied to treat such an anxiety disorders. And also a medical doctor can diagnose the patient in distance with the telemedicine system. In this thesis, an telemedicine assistant system for treatment of acrophobia using biomedical signals and virtual reality technique is proposed. I made two virtual reality simulations for treatment of acrophobia and telemedicine system for communication between doctor and patient using personal computer. Multimedia conference service, online questionary, signal transfer system are needed to configure such system. Virtual reality simulation system that composed of position sensor, head mount display, and audio system, is also included in this telemedicine system. I added virtual environment update system to this virtual reality telemedicine system for treatment of acrophobia. With this virtual environment update system, the doctors can change virtual reality simulation stage based on the status of each patient and symptom of phobia. We will apply this system to the acrophobia patient in distance and be able to offer better medical treatment for mental illness in near future.

• ETRI Journal
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• v.28 no.5
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• pp.583-592
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• 2006

Digital broadcasting technology has developed focusing on multi-channel/multi-media, high-definition quality, and mobility-support. Recently, there has been a clear trend toward bidirectional service with the convergence between broadcasting and communication. The broadcasting viewer is no longer simply a passive receptor but has also become an information generator. Currently, the digital multimedia broadcasting (DMB) specifications are the major standard for portable digital broadcasting and have been establishing the overall guidelines for bidirectional service using the MPEG-4 system. While detailed specifications for DMB systems are not well-established for bidirectional service yet, they share the basic concepts underlying the European Eureka-147 Digital Audio Broadcasting (DAB) system. This paper develops key scenarios for bidirectional service in DMB, describes the signal transaction of broadcasting and return channels, and demonstrates typical scenarios using binary format for scenes (BIFS) in the MPEG-4 system.

• Proceedings of the IEEK Conference
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• summer
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• pp.92-96
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• 2004

The researches of the emotions are currently great interest in speech processing as well as in human-machine interaction domain. In the recent years, more and more of researches relating to emotion synthesis or emotion recognition are developed for the different purposes. Each approach uses its methods and its various parameters measured on the speech signal. In this paper, we proposed using a short-time parameter: MFCC coefficients (Mel­Frequency Cepstrum Coefficients) and a simple but efficient classifying method: Vector Quantification (VQ) for speaker-dependent emotion recognition. Many other features: energy, pitch, zero crossing, phonetic rate, LPC... and their derivatives are also tested and combined with MFCC coefficients in order to find the best combination. The other models: GMM and HMM (Discrete and Continuous Hidden Markov Model) are studied as well in the hope that the usage of continuous distribution and the temporal behaviour of this set of features will improve the quality of emotion recognition. The maximum accuracy recognizing five different emotions exceeds $88\%$ by using only MFCC coefficients with VQ model. This is a simple but efficient approach, the result is even much better than those obtained with the same database in human evaluation by listening and judging without returning permission nor comparison between sentences [8]; And this result is positively comparable with the other approaches.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.835-838
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• 2002

A running high voltage equipments produce ultrasonic wave that has unique sound by the specific characteristics of the electricity. The generation of the ultrasonic wave is made by the electric transform like arcing, corona, and tracking so on. The mechanical losses and fatal human damages are happened by the electric failure of high voltage equipments. To prevent and diagnose the obstacle factors of the high voltage equipments, the measurement of the ultrasonic wave became to be prominent. However standardized data have been a deficient situation by now. This paper measures the ultrasonic wave coming from the real running transformer equipments and transforms it as an audio frequency. Measured data represents as frequency and time domain through the FFT(Fast Fourier Transform) transform. In conclusion, the purpose of this paper is to standardize the analyzed data.

• Journal of IKEEE
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• v.7 no.2 s.13
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• pp.188-196
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• 2003

In this paper, a demultiplexer for MPEG-2 Transport Stream which can be applied to terrestrial digital broadcast is developed. The demultiplexer separates video, audio, and data from MPEG-2 multimedia stream and transports them to each decoders respectively. While most existing demultiplexers of MPEG-2 transport stream have been developed as hardware systems, but the fast increment of computer's performance enables a software demultiplexer to be worked in realtime. The developed demultiplexer is implemented as a software module called a filter using DirectShow of Microsoft which is based on COM(Component Object Model)and works on the Windows system. The operation of the demultiplexer is verified by using the GraphEdit tool and rendering a test file formatted as MPEG-2 transport stream.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1383-1385
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• 1996

A network based interactive magnetic resonance imaging (MRI) system has been developed using the World Wide Web. For this purpose, an HTTP server is developed on the host computer of the MRI system. Capabilities of video and audio conferencing are included for monitoring experiment. Using the developed system. MRI imaging has been successfully carried out at the Signal Processing Lab in the Kwangwoon University with the remote MRI system located at the Medical Image Research Center at the KAIST in Daejon.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.139-142
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• 1996

A remotly controlled interactive magnetic resonance imaging (MRI) has been tried using the World Wide Web. For this purpose, an HTTP server is developed on the host computer of the MRI system. Video and audio conferencing capability is also included for the experiment. Using the developed system, MRI imaging has been successfully carried out at the Signal Processing Lab in the Kwangwoon University with the remote MRI system located at the Medical Image Research Center in the KAIST in Daejon.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.69-72
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• 2014

Recently, lighting systems using audio signal of audible frequency and frequency spectrum of visible lighting are studied. And various related products are being sold and released commercially. Also demands of emotional matching algorithm and system which includes effective and methodical designs are being increased. And the importance related with this scheme has increased. In this Paper, we configures a system for digital sound source based LED color control. And we develop algorithm to control LED color for the system configuration. Also we demonstrated the usefulness of the algorithm through experiment with simulation using LED color control system. We expected to be useful in a variety of fields and applications using proposed digital music based LED color control system.