• International journal of advanced smart convergence
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• 제2권2호
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• pp.16-18
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• 2013

In this paper, we develop a method to design a flexible thin film audio systems utilizing Polyvinylidene fluoride. The system we designed showed the properties of increased transparency and sound pressure levels. As an input terminal transparent oxide thin film is adopted. In order to provide dielectric insulation, a transparent insulating oxide thin film is coated to obtain double -layered structure. In the range of visible light, the output from the output of the system showed an increased and improved sound pressure level. The piezoelectric polymer film of polyvinylidene fluoride (PVDF) is used to produce mechanical vibration due to the applied electrical voltage signal. An analog electric voltage signal is transformed into sound waves in the audio system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 학술대회 논문집 전문대학교육위원
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• pp.179-182
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• 2007

The Design and Optimization of a low-profile antenna for the Satellite Digital Audio Radio System(SDARS) using a Non-Dominated Sorting Genetic Algorithm(NSGA) is presented. a fairly omni-directional elevation gain pattern over 60 degrees < q <60 degrees are obtained. The average value of the LCP gain pattern is approximately 2 dBic. The heights of the antennas are less than 0.251. The cross polarized signal level is approximately 12 dBic less than the co-polarized signal level.

• International Journal of Internet, Broadcasting and Communication
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• 제6권1호
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• pp.13-15
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• 2014

We develop a method to fabricate a flexible thin film audio systems using polyvinylidene fluoride(PVDF). The system we designed showed the properties of increased flexibility, transparency, and sound pressure levels. As an input port of two terminals, transparent oxide thin film with a low resistivity is adopted. In order to provide dielectric insulation, a transparent insulating oxide thin film is coated to obtain double-layered structure. In the range of visible light, the output from the output of the system showed a increased and improved sound pressure level. The piezoelectric polymer film of PVDF is used to produce mechanical vibration due to the applied electrical voltage signal. An analog electric voltage signal is transformed into sound waves in the audio system.

• 융합보안논문지
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• 제8권4호
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• pp.91-96
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• 2008

멀티미디어 데이터의 급격한 양적 팽창은 원하는 데이터를 빠르고 정확하게 검색해야 한다는 새로운 과제를 안겨주었다. 이러한 효율적 검색을 위해 가장 중요한 기반이 되는 것이 바로 데이터의 적절한 표준화이다. 2001년 국제 표준으로 제정된 MPEG-7은 바로 이러한 이유로 멀티미디어 데이터의 표현에 대한 표준화를 다루고 있다. 본 논문에서 설계한 시스템은 MPEG-7에서 요구하는 내용기반 검색 방법인 하위 레벨 메타데이터들을 이용한 유사성 검색과 상의 레벨 메타데이터들을 이용한 키워드 검색 기능을 제공할 것이다. 또한, 상위 레벨 메타데이터와 하위 레벨 메타데이터들을 통합하여 검색하는 기능을 제공하여 사용자가 원하는 멀티미디어 정보를 보다 효율적으로 검색할 수 있도록 할 것이다.

• The Journal of the Acoustical Society of Korea
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• 제29권3E호
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• pp.131-139
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• 2010

This paper proposes a novel spectral hole substitution technique for low bit-rate audio coding. The spectral holes frequently occurring in relatively weak energy bands due to zero bit quantization result in severe quality degradation, especially for harmonic signals such as speech vowels. The enhanced aacPlus (EAAC) audio codec artificially adjusts the minimum signal-to-mask ratio (SMR) to reduce the number of spectral holes, but it still produces noisy sound. The proposed method selectively predicts the spectral shapes of hole bands using either intra-band correlation, i.e. harmonically related coefficients nearby or inter-band correlation, i.e. previous frames. For the bands that have low prediction gain, only the energy term is quantized and spectral shapes are replaced by pseudo random values in the decoding stage. To minimize perceptual distortion caused by spectral mismatching, the criterion of the just noticeable level difference (JNLD) and spectral similarity between original and predicted shapes are adopted for quantizing the energy term. Simulation results show that the proposed method implemented into the EAAC baseline coder significantly improves speech quality at low bit-rates while keeping equivalent quality for mixed and music contents.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.241-242
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• 2006

MPEG Surround is an audio coding technology that represents multi-channel audio signal with downmixed audio signal(s) and very low bitrate side information based on Binaural Cue Coding. The side information consists of Inter-Channel Level Difference, Inter-Channel Correlation, and payloads. These two parameters are correspondent to the well-known spatial parameters in psycho-acoustics, Inter-aural Level Difference (ILD) and Inter-Aural Cross Correlation (IACC). Though ICLD is to provide perceptually equivalent ILD to the listener, however, the ILD of the original multi-channel audio signal and that of the MPEG Surround encoded signal was different. The difference between two ILD values is defined as ILD Distortion (ILDD). This paper provides how ILDD can be applied to enhance sound quality in MPEG Surround and how much ILDD is decreased.

• 한국통신학회논문지
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• 제24권8A호
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• pp.1169-1178
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• 1999

본 논문에서는 현재 유럽에서 데이터와 음성 서비스를 하고 있는 GSM(Global System for Mobile Communication)용 디지털 단말기를 Handheld PC에 빌트인 할 경우 나타나는 오디오 노이즈의 개선 방법을 제시하고 있다. 서비스 가운데 가장 큰 문제인 음성 품질을 GSM규격 항목에 만족하기 위해서는, HPC 메인보드에서 전원 그리운드와 가장 가깝고 면적이 가장 넓은 부분을 중심으로 선택하여 GSM모듈과 와이어를 직접 연결하여 임피던스 차이를 최소로 하고, 전치 증폭기와 Earpiece에 있어서는 본 논문에서 제시한 Low Noise 설계를 통하여, 오디오 노이즈를 개선하였다. 측정 결과는 GSM 음성(Acoustic)규격을 만족한다. 측정결과는 B&K Type 6712(GSM 전용장비)를 이용하여 GSM 11.10 ETS 300 607-1의 음성(Acoustic)규격 항복을 측정하였다. 본 연구에서 측정한 항목으로는 다음의 Sending Sensitivity Frequency Response and SLR, Sending Loudness Rating(SLR level), Receiving Sensitivity Loudness Rating(RLR level), Talker Sidetone(STMR), Stability Margin, Echo Return Loss(ERL)으로 6가지 항목이다.

• 전자공학회논문지CI
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• 제49권4호
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• pp.16-22
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• 2012

본 논문에서는 심리음향 모델(Psychoacoustic model) II와 MDCT를 이용한 고음질 오디오 포렌식 마킹 알고리즘을 제안한다. 제안된 알고리즘은 오디오 신호의 에너지가 스펙트럼 마스킹 레벨보다 적은 서브밴드를 선택하여 콘텐츠 사용자의 핑거프린팅 코드를 삽입하는 포렌식 마킹 방법이다. 원 오디오 신호의 FFT 처리를 위한 2,048 샘플의 한 프레임 범위에서, 3개의 서브밴드를 선택하여 포렌식 마킹을 한다. 핑거프린팅 코드의 평균화 공격에 따른 공모코드의 100% 추적율을 갖는 범위에서, 한 프레임의 SNR을 측정하였다. 핑거프린팅 코드의 최저강도 0.1 삽입에서 SNR은 38.44dB 이며, 화이트 가우시안 노이즈의 강도 0.5가 추가된 SNR은 19.09dB로 제안된 오디오 포렌식 마킹 알고리즘은 핑거프린팅 코드의 마킹 강인성과 오디오 고음질이 유지됨을 확인하였다.

• ETRI Journal
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• 제27권5호
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• pp.608-616
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• 2005

Watermarking has become a technology of choice for a broad range of multimedia copyright protection applications. This paper proposes an audio watermarking scheme that uses the modified tonal masker as an embedding carrier for imperceptible and robust audio watermarking. The method of embedding is to select one of the tonal maskers using a secret key, and to then modify the frequency signals that consist of the tonal masker without changing the sound pressure level. The modified tonal masker can be found using the same secret key without the original sound, and the embedded information can be extracted. The results show that the frequency signals are stable enough to keep embedded watermarks against various common signal processing types, while at the same time the proposed scheme has a robust performance.

• ETRI Journal
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• 제27권3호
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• pp.330-333
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• 2005

The Inter-Channel Level Difference (ICLD) is a cue parameter to estimate spectral information in a binaural cue coding that has been recently in the spotlight as a multichannel audio signal compression technique. Even though the ICLD is an essential parameter, it is generally distorted by quantization. In this paper, a new modified ICLE representation method to minimize the quantization distortion is proposed by adopting a flexible determination of the reference channel and the unidirectional quantization. Our experimental result confirms that the proposed method improves the multichannel audio output quality even with the reduced bit-rate.