• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.1182-1187
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• 2006

본 논문은 필립스의 오디오 핑거프린트 추출 방식을 기반으로 기존의 방식이 주파수 영역을 너무 조밀하게 분석하는 특징을 지적하고 개선 방안으로 양자화를 통해 필터 뱅크의 에너지 변화율을 오디오 핑거프린트 추출시 반영하는 방법을 제안하였다. 또한 제안된 알고리즘을 사용하여 PDA 로 실제 어플리케이션을 구현하는 것을 목적으로 하고 있다. 제안된 방식은 필립스 방식과 동일한 메모리 크기를 유지하기 위하여 필터 뱅크의 개수를 33 개에서 17 개로 줄이고 필터 뱅크의 변화량을 2 비트로 할당하는 방식을 사용하였다. 변화량을 비트에 할당하기 위하여 음악 데이터 베이스로부터 추출된 각 밴드의 pmf를 통해 음악의 고유성을 최대로 증진 시킬 수 있는 임계치를 찾아내고 이것을 바탕으로 필터 뱅크의 변화량을 2 비트로 할당하였다. 이 같이 추출된 오디오 핑거프린트를 기반으로 PDA 와 음악 검색기 서버와의 통신을 이용하여 사용자가 요청한 쿼리 음악에 관련된 정보를 제공하는 시스템을 구현했다. 제안된 방식은 다양한 주변 잡음 환경에서 평가되어 기존의 필립스 방식 보다 성능 향상 물론 검색 속도 또한 개선되는 특징을 확인할 수 있었다.

• Journal of Korea Multimedia Society
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• v.20 no.3
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• pp.446-455
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• 2017

A color image compression based on saliency map was proposed. The proposed method provides higher quality in saliency blocks on which people's attention focuses, compared with non-saliency blocks on which the attention less focuses at a given bitrate. The proposed method uses 3 different quantization tables according to each block's saliency level. In the experiment using 6 typical images, we compared the proposed method with JPEG and other conventional methods. As the result, it showed that the proposed method (Qup=0.5*Qx) is about 3.1 to 1.2 dB better than JPEG and others in saliency blocks in PSNR at the almost similar bitrate. In the comparison of result images, the proposed one also showed less error than others in saliency blocks.

• Journal of Biomedical Engineering Research
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• v.12 no.2
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• pp.79-88
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• 1991

Semi-transparent volume rendering technique can provide 3-D visualization well by voxel level Processing and alleviate segmentation arf, ifacts compared wish the surface rendering technique. In this Paper, we consider several new schemes which can improve she Perform ance of volume rendering. A directional interpolation method is proposed to reduce the artifact due to the anisotrophic resolution in X-ray CT data. The computation time for rendering is shortened by using the depth information of the 3-D object. And also, we reduce the quantization artifacts in the rendering by introducing the opacity-dependent sampling interval to sampling in ray-tracing.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1880-1885
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• 1989

In this paper, a new approach for systolic array realizing the discrete cosine transform (DCT) based on discrete Fourier transform (DFT) of an input sequence is presented. The proposed array is based on a simple modified DFT(MDFT) version of the Goertzel algorithm combined with Kung's approach and is proved perfectly. This array requires N cells, one multiplier and takes N clock cycles to produce a complete N-point DCT and also is able to process a continuous stream of data sequences. We have analyzed the output signal-to-noise ratio(SNR) and designed the circuit level layout of one-PE chip. The array coefficients are static adn thus stored-product ROM's can be used in place of multipliers to limit cost as eliminate errors due to coefficients quantization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1546-1552
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• 1993

We proposed an adaptive block truncation coding(BTC) using gradient and a new initial value. We used gradient of sobel operator as a new category classification coefficient to reduce Jagged appearance at edge part. We defined a new initial value to reduce large quantization error in the 4-level quantizer block including edge part. By computer simulations, we showed that the proposed method less computation load, reduced jagged appearance at edge part, also improved PSNR more than the conventional adaptive BTC.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.152-155
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• 2000

Oversampling modulators based on high-order sigma-delta modulation provide an effective means of achieving high-resolution A/D conversion in a VLSI technology. Because high-order noise shaping great]y reduces the quantization noise in the signal band. This paper introduces a third-order cascaded sigma-delta modulator that is stable for large input level. Modulator was simulated 3.3V single power supply voltage in 0.65$\mu\textrm{m}$ CMOS technology. It achieves 80㏈ SNR for a 20㎑ input signal bandwidth. A lock frequency is 3㎒ that is 80 oversampling ratio.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.316-322
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• 1998

Super precision working technique and machine tool have been developing continually thanks to advanced electronic field. To obtain good result. it is necessary to investigate surface state in grinding with ${\mu}{\textrm}{m}$ level. There were so many researches to satisfy these demands using non-contact methods through the computer vision. In this study, the texture of working surface was analyzed. cooccurrence matrice was obtained from the surface roughness. Texture parameter was obtained by means of position operator compose of $\theta$. d according to variation of angle direction and distance. As a result, it was found that surface texture was more effected by direction ($\theta$) then distance(d).

• Journal of the Korea Safety Management & Science
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• v.16 no.3
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• pp.273-277
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• 2014

Subcontracting business than the contracting business in shipbuilding industry is a lot of hazardous job and highly accident because of highly work intensity. In order to prevent the accidents, there is a need to analyze characteristic. of shipbuilding, to apply measures of risk assessment. In this paper, I suggested an improvement of the risk assessment through the actual condition research in shipbuilding industry. In the research method, I analysed accidents occurred until 2011-2013. Carried out the actual site survey while two weeks in May 2014. As a result, 1) The main pattern were caught-in or between, fall on the high level according to analyzed accidents. 2) To apply the weight show clear of magnitude for risk assessment. 3) Risk estimation of risk assessment is desirable to be quantization by accidents analysis, and to be greater than or equal to 4 steps.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2467-2470
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• 2003

This paper presents a new structure of MPEG-4 AAC encoder. The proposed encoder directly shapes quantization noise distribution according to the energy distribution curve and thereafter performs adjustment of the offset level of the noise distribution to meet the given bit rate. The direct noise shaping and the bit rate matching scheme of the proposed encoder algorithm significantly alleviate the problem of conventional encoder's processing burden related with the employment of the precise psychoacoustic model and iteration intensive quantizer. The encoder algorithm is implemented on ARM processor with fixed-feint arithmetic operations. The audio quality of the implemented system is observed comparable to those of commercially available encoders, white the complexity of the implementation is drastically reduced in comparison to the conventional encoder systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.6
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• pp.567-572
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• 2004

This paper shudies an automatic gain control(AGC) algorithm used in wireless communication cellular systems. The AGC design includes the selection of the appropriate analog-to-digital converter(ADC) and keeping the input power to the ADC constant to minimize the quantization noise generated from the analog-to-digital conversion process. In this paper the process to determine the required precision or the An is illustrated and the method to set the design parameters of the AGC is proposed. And the validity of the proposed algorithm is verified by computer simulation.