• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.779-782
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• 2013

오늘날 우리 생활에 영상이나 이미지는 우리 실생활에 아주 밀접하게 연관되어 있다. 카메라, 휴대폰, TV, 영상 및 이미지 관련 기기들이 증가하고 이로 인해 영상이나 이미지 관련 서비스의 기술적인 요소들이 중요시되고 있다. 이러한 영상에서 기본적으로 사용하는 압축방식인 DCT는 직교 변환 방식의 국제 표준으로써, 정지 이미지나 동영상의 압축 파일등에서 사용된다. DCT(Discrete Cosine Transform) 알고리즘은 음성 및 영상 압축 등 많은 디지털 신호처리 분야에서 사용되고 있다. 본 논문에서는 WMV의 $4{\times}4$, $4{\times}8$,$8{\times}4$, $8{\times}8$ 4가지 모드에 대해 DCT를 지원할 수 있도록 C언어를 통해 상위 수준의 검증을 수행하고, 이를 HDL을 사용하여 코딩하고, Modelsim SE6.1을 사용해 회로 검증하였다.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.11
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• pp.69-70
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• 1992

We have designed the speech signal processor for cochlear prosthesis using quadrature mirror filter (QMF). And it is real-time implemented using DSP macros TMS 320C30.

• The Journal of the Acoustical Society of Korea
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• v.17 no.8
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• pp.82-87
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• 1998

음성합성은 합성방식에 따라 파형부호화법, 신호원부호화법, 혼성부호화법으로 분류 할 수 있다. 특히 고음질 합성을 위해서는 파형부호화를 이용한 합성방식이 적합하다. 그렇 지만, 파형부호화를 이용한 합성법은 여기 성분과 여파기 성분을 분리하지 않고 처리하기 때문에 음절단위나 음소단위의 합성기법으로는 바람직하지 못하다. 따라서 파형부호화법을 규칙에 의한 합성에 적용되도록 음원피치를 변경시키기 위한 피치 변경법이 필요하게 된다. 본 논문에서는 스펙트럼 왜곡을 최소화하기 위해 켑스트럼의 성질을 이용하여 피치를 변경 하는 방법에 대하여 제안하였다. 이 방법은 주파수영역상에서 여기 스펙트럼과 여파기 스펙 트럼을 분리하여 여기 스펙트럼을 여기 켑스트럼으로 변환한 후 영값 삽입이나 삭제에 의해 피치를 변경하고 스펙트럼영역에서 피치 변경된 스펙트럼을 재구성하는 기법을 적용하였다. 제안한 방법의 성능을 평가하기 위해 스펙트럼 왜곡율을 측정하여 본 결과 평균 스펙트럼 왜곡율은 평균 2.29%이하로 유지되었으며 주관적인 음질도 평균 3.74로 우수하였다.

• Information and Communications Magazine
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• v.19 no.4
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• pp.53-61
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• 2002

세계는 현재 디지털 혁명에 의한 새로운 정보통신(IT) 서비스의 홍수에 직면해있다. '언제, 어디서나, 사용자의 요구에 맞추어'라는 말은 이미 모든 서비스 기술개발 분야에서 캐치프레이즈로 자리잡은지 오래 되었다. 통신은 기존 전화를 통한 음성 서비스 위주에서 점차 데이터 통신으로 무게 중심이 이동되고 있고, 방송도 단순한 영상물 중심의 프로그램 전달이 아닌 개인별 정보 전달 및 양방향 통신에 의한 부가서비스로 그 영역을 확장해가지고 있다. 이런 변화의 중심에는 역시 '디지털' 기술에 의해 가능한 '융합(Convergence)' 화를 위한 기술개발이 그 동력을 제공하고 있으며, 프로세서 , 메모리, 디스플레이, 모뎀 등 하드웨어의 발전과 함께 오디오비쥬얼 신호 압축 및 전송, 웹 문서처리 등 소프트웨어적인 기술 개발 및 표준화 결과를 상호 유기적이고 통합적으로 각 응용 서비스 시스템에 적용함으로써 가능해지고 있다. 본 고에서 데이터 방송, 지능형 방송 및 MPEG-21 멀티미디어 프레임워크 표준을 중심으로 방송의 입장에서 본 방송통신융합의 기술개발 현황과 전망에 대해 개괄해보기로 한다.

• Composites Research
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• v.16 no.4
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• pp.74-79
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• 2003

Comparison of interfacial properties and microfailure mechanisms of oxygen-plasma treated poly(p-phenylene-2,6-benzobisoxazole(PBO. Zylon) and poly(p-phenylene terephthalamide)(PPTA, Kevlar) fibers/ epoxy composites were investigated using micromechanical technique and nondestructive acoustic emission(AE). Interfacial shear strength(IFSS) and work of adhesion, Wa of PBO or Kevlar fibers/epoxy composites increased by oxygen-plasma treatment. Plasma-treated Kevlar fiber shooed the maximum critical surface tension and polar term, whereas the untreated PBO fiber showed the minimum value. Microfibril fracture pattern of plasma-treated Kevlar fiber appeared obviously. Based on the propagation of microfibril failure toward core region. the number of AE events for plasma-treated PBO and Kevlar fibers increased significantly. The results oi nondestructive AE were consistent well with microfailure modes by optical observation in microdroplet and two-fiber composites tests.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.1
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• pp.51-55
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• 1988

This studies conducted to investigates shelf-life of fresh pork chop by using various packaging method such as aerobic packaging, aerobic packaging with lactobacilli, vacuum packaging and vacuum packaging with lactobacilli. Bacteriological and physicochemical proper ties of fresh pork chop were also investigated during storage at $4^{\circ}C$. The effect of lactobacilli treatment showed significantly in aerobic packaging and vacuum pactaging. The growth of lactobacilli did not occur in lactobacilli inoculated fresh pork chops. The gram-negative bacteria which caused to meat spoilage was inhibited by lactobacilli. The PH of Pork showed increasing tendancy regardless of treatments, TBA and VBN value appeared to be relatively low during storage at $4^{\circ}C$. The maximum shelf life of each treatments was 12-15 days of aerobic packaging. 20-25 days of vacuum packaging and aerobic packaging with lactobacilli and 30-35 days of vacuum pactaging with lactobacilli at $4^{\circ}C$ respectively.

• The KIPS Transactions:PartB
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• v.10B no.2
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• pp.169-178
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• 2003

This study outlines two viewpoints the classification of phone likely unit (PLU) which is the foundation of korean large vocabulary speech recognition, and the effectiveness of Chiljongseong (7 Final Consonants) and Paljogseong (8 Final Consonants) of the korean language. The phone likely classifies the phoneme phonetically according to the location of and method of articulation, and about 50 phone-likely units are utilized in korean speech recognition. In this study auditory phonetical knowledge was applied to the classification of phone likely unit to present 45 phone likely unit. The vowels 'ㅔ, ㅐ'were classified as phone-likely of (ee) ; 'ㅒ, ㅖ' as [ye] ; and 'ㅚ, ㅙ, ㅞ' as [we]. Secondly, the Chiljongseong System of the draft for unified spelling system which is currently in use and the Paljongseonggajokyong of Korean script haerye were illustrated. The question on whether the phonetic value on 'ㄷ' and 'ㅅ' among the phonemes used in the final consonant of the korean fan guage is the same has been argued in the academic world for a long time. In this study, the transition stages of Korean consonants were investigated, and Ciljonseeng and Paljongseonggajokyong were utilized in speech recognition, and its effectiveness was verified. The experiment was divided into isolated word recognition and speech recognition, and in order to conduct the experiment PBW452 was used to test the isolated word recognition. The experiment was conducted on about 50 men and women - divided into 5 groups - and they vocalized 50 words each. As for the continuous speech recognition experiment to be utilized in the materialized stock exchange system, the sentence corpus of 71 stock exchange sentences and speech corpus vocalizing the sentences were collected and used 5 men and women each vocalized a sentence twice. As the result of the experiment, when the Paljongseonggajokyong was used as the consonant, the recognition performance elevated by an average of about 1.45% : and when phone likely unit with Paljongseonggajokyong and auditory phonetic applied simultaneously, was applied, the rate of recognition increased by an average of 1.5% to 2.02%. In the continuous speech recognition experiment, the recognition performance elevated by an average of about 1% to 2% than when the existing 49 or 56 phone likely units were utilized.

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.105-112
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• 2001

In this paper, we present the advanced QCELP codebook search improving the qualification of speech, which can make QCELP vocoder used in noise robust system. While conventional QCELP usually searches stochastic codebook once, we can find that two times search is the most suitable for improving the quality of speech after we did 2-5 times search. Consequently, the advanced QCELP vocoder represents excitation signal in detail using two times precise quantization and so improve the qualification of speech. In our experiment, we use the speeches collected from circumstance (such as lecture room, house, street, laboratory etc.) without regarding noise as input dat and measure the speech Qualification using SNR, segSNR. As the result of the experiment, we find that the advanced QCELP makes SNR and segSNR improved by 38.35% and 65.51% respectively compared with conventional QCELP.

• The Journal of the Acoustical Society of Korea
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• v.18 no.5
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• pp.63-67
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• 1999

Recently, a method of measuring impulse response is widely used for a room acoustic evaluation instead of measuring reverberation time by white noise excitation. Comparing with the traditional reverberation time measurement, this method has many advantages such as good repeatability and the ability to extract various room acoustic parameters at one measurement. In this study, the author developed a measuring system that can extract mono-aural room acoustic parameters from an impulse response measured with MLS (Maximum Length Sequence) signal excitation. These room acoustic parameters include reverberation times(EDT, RT), speech intelligibilities(C50, C80, D, U50, U80, AI) and sound strength(G). This paper introduces the configuration of the developed measuring system, test results and discussions for the measurements at several rooms.

• The Journal of the Acoustical Society of Korea
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• v.19 no.3
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• pp.57-62
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• 2000

In recent, the innovative improvement of a internet and computing environment make users desire the capability of processing information in real time. In this paper we implement a PC-to-PC real time multi-user communication system on the internet environment using the efficient algorithm for a real time processing and the MFEG-4 CELP codec which can be used for a low bit-rate coding from 6 to 24kbps. The implemented system produces a compressed bit-streams with the MPEG-4 CEU Mode-I 18200bps mode. There is 5 frames for a package and 1 frame has 160 samples. We can use this system to communicate with 4 users simultaneously in real time. The system is designed and examined on the Windows operating system.