• The Journal of the Acoustical Society of Korea
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• v.17 no.7
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• pp.12-21
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• 1998

본 논문은 음성 부호화기인 MPMLQ(Multi Pulse Maximum Likehood Quantization)를 고정 소숫점 범용 DSP에 실시간으로 구현할 때 발생되는 계산량을 줄이기 위한 변형된 형태의 MPMLQdp 관한 것이다. MPMLQ는 음성 신호에서 선형 예측 계수와 피치 정보를 추출하고 남은 잔여 신호와 가장 유사한 여기 신호를 표현할 때 상관법을 이용 한다. 상관법은 DSP상에 구현할 때 계수 승산 오버플로우를 발생시킬 수 있으므로 연산후 항상 점검하여야 한다. 이것은 MPMLQ 구현시 전체 계산량의 많은 부분을 차지한다. 본 논 문은 이러한 문제점에 착안하여 계수 승산 오버플로우가 발생하지 않도록 입력 음성신호의 크기를 2비트 만큼 줄이고, 이로 인하여 같은 크기로 줄어든 잔여 신호를 고려하여 MPMLQ에서 여기신호의 크기를 표현하는 고정 코드북 이득표를 적절히 조절하였다. 실험 결과 변형된 MPMLQ의 SSNR은 0.040325dB(실험data기준) 향상되었으며, 계산량에 있어서 도 17.7%의 처리속도 향상되었다. 따라서 고정 소숫점 범용 DSP에 실시간 구현이 가능하였다.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.489-492
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• 1995

This paper has represented the new system for a multibit oversampled sigma-delta A/D convertor. The novel digital correction scheme with the ROM-Table is employed to enhance SNR without requiring accurate precision of the analogue components. This architectures have a good features compared with the 1-bit approach, including significantly lower quantization noise for a given oversampling ratio, as well as improved stability characteristics. Then we have shown the validity of the proposed system by use of the software for the performance evaluation and by realizing the system with SCFs(switched capacitor filter).

• Speech Sciences
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• v.2
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• pp.57-66
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• 1997

This paper studies the effects of the method, CMS(Cepstral Mean Subtraction), (which compensates for some of the speech distortion. caused by telephone channels), on the performance of the text-dependent speaker identification system. This system is based on the VQ(Vector Quantization) and HMM(Hidden Markov Model) method and chooses the LPC-Cepstrum and Mel-Cepstrum as the feature vectors extracted from the speech data transmitted through telephone channels. Accordingly, we can compare the correct recognition rates of the speaker identification system between the use of LPC-Cepstrum and Mel-Cepstrum. Finally, from the experiment results table, it is found that the Mel-Cepstrum parameter is proven to be superior to the LPC-Cepstrum and that recognition performance improves by about 10% when compensating for telephone channel using the CMS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.2
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• pp.108-120
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• 1989

The paper describes a new algorithm for reducing the edge degradation of a vector quantization(VQ) in low rates. This algorithm exploits several codebooks, one of which is adaptively selected by standard deviation(SD) of the vector currently being coded. Also, SD search method for reducing the complexity of codebook search is proposed. As a result, a proposed VQ has good performance anout 30 dB PSNR in the 0.4-0.7 bpp range.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.6
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• pp.542-546
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• 2007

In the vision of ubiquitous computing environment, smart objects would communicate each other and provide many kinds of information about user and their surroundings in the home. This information enables smart objects to recognize context and to provide active and convenient services to the customers. However in most cases, context-aware services are available only with expert systems. In this paper, we present generalized activity recognition application in the smart home based on a naive Bayesian network(BN) and fuzzy clustering. We quantize continuous sensor data with fuzzy c-means clustering to simplify and reduce BN's conditional probability table size. And we apply mutual information to learn the BN structure efficiently. We show that this system can recognize user activities about 80% accuracy in the web based virtual smart home.

• Journal of Digital Contents Society
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• v.17 no.5
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• pp.433-439
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• 2016

In this paper, we propose a optimized steganography how to improve the image degradation of the existing data hiding techniques. This method operates in the compressed domain(JPEG) of an image. Most of the current information concealment methods generally change the coefficients to hide information. And several methods have tried to improve the performance of a typical steganography method such as F5 including a matrix encoding. Those papers achieved the object of reducing the distortion which is generated as hiding data in coefficients of compressed domain. In the proposed paper we analyzed the effect of the quantization table for hiding the data in the compressed domain. As a result, it found that can decrease the distortion that occur in the application of steganography techniques. This paper provides a little (Maximum: approximately 6.5%) further improved results in terms of image quality in a data hiding on compressed domain. Developed algorithm help improve the data hiding performance of compressed image other than the JPEG.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.6
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• pp.665-674
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• 2001

In this paper, a reduced complexity fillet to simultaneously suppress the blocking and ringing artifacts of compressed video sequence is addressed. A new one dimensional regularized function to incorporate the smoothness to its neighboring pixels into the solution is defined, resulting in very low complexity filter The proposed regularization function consists of two sub-functions that combine local data fidelity and local smoothing constraints. The regularization parameters to control the trade-off between the local fidelity to the data and the smoothness are determined by available overhead information in decoder, such as maroc-block type and quantization step size. In addition, the regularization parameters are designed to have the limited range and stored as look-up-table, and therefore, the computational cost to determine the parameters can be reduced. The experimental results show the capability and efficiency of the proposed algorithm.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.636-639
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• 2004

In present, there are many methods such as DCT, Wavelet Transform, or Quantization -to the image compression field, but the basic image compression method have based on DCT. The representative thing of the efficient techniques for information compression is DCT method. It is more superior than other information conversion method. It is widely applied in digital signal processing field and MPEG and JPEG which are selected as basis algorithm for an image compression by the international standardization group. It is general that DCT is consisted of using multiplier with main arithmetic blocks having many arithmetic amounts. But, the use of multiplier requires many areas when hardware is embodied, and there is fault that the processing speed is low. In this paper, we designed the hardware module that could run high-speed operation using row-column separation calculation method and Chen algorithm by distributed arithmetic method using ROM table instead of multiplier for design DCT module of high speed.

• Mass Spectrometry Letters
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• v.7 no.1
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• pp.26-29
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• 2016

Simultaneous determination of three corticosteroids (clobetasol propionate, betamethasone dipropionate, fluticasone propionate) in moisturizers was performed by using liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS). Sample preparation was conducted by the liquid-liquid extraction (LLE). Moisturizers include emulsifying agent and it forms micelles. In order to improve the extraction efficiency of corticosteroids trapped in micelle, newly developed-optimized extraction conditions which can remove the matrix effect from moisturizers was applied with various pH conditions in LLE extraction stage of sample preparation. Thus, the addition of 10 μL of 1 M HCl into moisturizers sample before extraction could improve the extraction efficiency. For the quantitative analysis, SRM table that contained specific transition of all of target corticosteroids was created. The developed method was validated for linearity, accuracy, precision, limit of detection (LOD), limit of quantization (LOQ) and recovery. Over the 0.99 r² value was obtained in calibration standard range. Effective accuracy and precision were also obtained. LODs were below 31 ng/mL and LOQs were estimated below 94 ng/mL for all corticosteroids tested.

• Journal of Broadcast Engineering
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• v.6 no.2
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• pp.187-194
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• 2001

The Advanced Intra Coding(AIC) mode included in the H.263+ which is for video ceding at low bit rates, selects one prediction direction of DCT coefficients among three directions for every intra macroblock. Based ()n the selected direction, It uses a different DCT scanning order, quantization scheme, and VLC table. The use of the AIC mode brings higher compression ratio and improved PSNR than the H.263 baseline. This paper proposes a simplified submode selection method for a direction of the DCT coefficient prediction for advanced ultra coding in H.263. Compared to the conventional method the proposed simplified method can achieve a similar coding Performance at computational complexity reduced to 1/7 and with much less memory requirement. The proposed method will be useful in implementing a simplified H.263 system.