• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.299-302
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• 2009

본 논문에서는 프레임 안에서의 인접픽셀간의 복잡도를 이용하여 할당비트 조절과 장면 전환을 추정하는 H.264/AVC 비트율 제어 기법을 제안한다. Quadratic 율-왜곡 모델은 프레임 할당 비트와 선형 모델을 통해 예측된 MAD정보를 필요로 한다. 이때 장면전환과 같은 급격한 화질 변화는 예측된 MAD정보만으로는 적합한 양자화파라미터를 결정하지 못하고 이후 비트율 제어를 어렵게 한다. 제안하는 방법은 프레임 안에서 인접픽셀간의 차분 값들의 절대 합을 구하여 이전프레임과 현제프레임의 비로 나타낸 후 이 값의 일정 범위를 벗어나면 장면전환이 이루어진 것으로 간주하여 이에 알맞은 양자화 파라미터 결정기법을 적용하도록 하였다.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.838-846
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• 2016

Most of combustion processess used in industries require recovering or removing flue gas components. Recently a new MBA (moving bed adsorption) process for recovering $CO_2$ using zeolite 13X was developed. In this study, adsorption experiments for carbon dioxide, nitrogen, sulfur dioxide, and water vapor on zeolite 13X were carried out. Adsorption equilibrium and adsorption rate into solid particle were investigated. Langmuir, Toth, and Freundlich isotherm parameters were calculated from the experiment data at various temperatures. Experimental results were consistent with the theoretically predicted values. Also $CO_2$ adsorption amount was measured under the conditions with impurities such as $SO_2$ and $H_2O$. Binary adsorption data were well fitted to the extended Langmuir isotherm using parameters obtained from pure component experiment. However, $H_2O$ impurity less than, roughly, ${\sim}10^{-5}H_2O\;mol/g$ zeolite 13X enhanced slightly $CO_2$ adsorption. Spherical particle diffusion model well described experimentally measured adsorption rate. Diffusion coefficients and activation energies of $CO_2$, $SO_2$, $N_2$, $H_2O$ were obtained. Diffusion coefficients of $CO_2$ and $SO_2$ decreased with small amount of preadsorbed impurity. Parameter values from this study will be helpful to design of real commercial adsorption process.

• Journal of Broadcast Engineering
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• v.21 no.4
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• pp.592-608
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• 2016

Recently, many researches on digital holograms, which retain almost perfect 3 dimensional image information, have been performed actively that it seems for them to be serviced soon. Accordingly, this paper proposes a data compression technique for a digital hologram video for this service. It uses H.265/HEVC, the most recent international 2 dimensional video compression standard, for which we consider various domain transform methods to increase the correlation among the pixels in a digital hologram. Also we consider the various parameters on H.265/HEVC. The purpose of this paper is to find empirically the optimal condition for the domain transform method, the size of transform unit, and the H.265/HEVC parameters. The proposed method satisfying the optimal parameter set found is compared to the existing methods to prove that ours shows better performance.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.6
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• pp.46-54
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• 1998

This paper presents a method for designing robust fuzzy $H^{\infty}$ controllers which stabilize nonlinear systems with parameter uncertainty adn guarantee an induced $L_{2}$ norm bound constraint on disturbance attenuation for all admissible uncertainties. Takagi and Sugeno's fuzzy models with uncertainty are used as the model for the uncertain nonlinear systems. Fuzzy control systems utilize the concept of so-called parallel distributed compensation(PDC). Using a single quadratic Lyapunov function, the stability condition satisfying decay rate and disturbance attenuation condition for Takagi and Sugeno's fuzzy model with parameter uncertainty are discussed. A sufficient condition for the existence of robust fuzzy $H^{\infty}$ controllers is then presented in terms of linear matrix inequalities(LMIs). Finally, design examples of robust fuzzy $H^{\infty}$ controllers for uncertain nonlinear systems are presented.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.262-264
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• 2009

일반적으로, 단위 배터리간의 직/병렬 연결을 통해 구성되는 팩은 이를 구성하는 각 배터리간의 상이한 전기화학적 특성으로 인해 전압 불균형이 존재한다. 이러한 전압 불균형은 팩의 노화 및 성능을 저하시키는 원인이 된다. 이러한 전압불균형을 없애기 위해 전압과 State of Charge(SOC)를 이용한 밸런싱 회로가 폭넓게 연구되고 있다. 하지만, 이러한 연구는 대체적으로, 다른 특성을 가지는 단위 배터리로 구성되는 팩의 밸런싱 방법이다. 따라서, 동일하고 균일한 특성을 갖는 배터리들을 미리 선별하여 팩을 구성한다면, 밸런싱의 전반적인 효율증대가 기대된다. 본 논문에서는 최적의 전압 밸런싱을 위한 스크리닝(Screening)의 새로운 방법을 연구하였다. 용량과 모델 파라미터(Lumped resistance;$R_{Diff}$)를 스크리닝의 척도로 고려하였고, 전압 불균형을 최대한 줄이기 위해 용량, 모델 파라미터의 순으로 스크리닝을 진행하였다. 또한, 전압패턴인식을 이용한 판별법을 통해 제안된 스크리닝 방법을 검증하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.12
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• pp.77-84
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• 2004

We design and implement the DSP module for automotive radar using FMCW. The designed parameters are based on 77GHz FMCW radar, and show the resolution of 0.4m and 0.67km/h in distance and velocity, respectively. For detecting multiple targets, we discuss the relationship between fb's and targets. In addition, we show that the detection of multiple targets is very simple when the range of $f_r$ is sufficiently larger than that of $f_b$. In the front of ADC, the 2nd order differentiator is applied for reducing the effects of path-loss so that the ADC bits are reduced to 8 bits. The designed block is simulated in Matlab and implemented with DSP and micro-processor.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.40-45
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• 2004

This paper presents the parallel distributed control scheme for shaping of the bent glass. The designed system consists of a PC, a main controller and 11 servo-controllers, the precision motion controllers. Each elements are connected by using RS-232C and 8-bit data bus. In order to guarantee the stability and the control performance, we use a precision PID motion controller and a H-bridge on the servo-drivers. PC calculates position values of 11 DC motors by using the pre-determined curvature value and offers the user interface environment operator. The main controller provides the control instructions and parameter values to 11 servo-controllers by chip enable signal, simultaneously. Using the received commands and parameter values, the servo-controllers control the positions of the DC motors based on PID control scheme.

• Journal of the Korean Chemical Society
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• v.32 no.4
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• pp.351-357
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• 1988

The electrochemical reduction of uranyl ion at the dropping mercury electrode and/or mercury microelectrode has been studied in propanediol-1,2-carbonate (PDC) by voltammetric techniques. The position of peak potentials, the nature of limiting currents, their dependency on temperature and on concentrations, reversibility of electrode reactions, and influence of addition of phenol are described. The influence of PDC in aqueous solution of uranyl ion was also described. The values of kinetic parameters, viz., transfer coefficient, formal constant for the electrode reactions bave been determined by Koutecky's method as extended by Meites and Israel. The values of ${\Delta}H,\;{\Delta}G\;and\;{\Delta}S$ have also been calculated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3B
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• pp.529-540
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• 2000

This is paper presents the semantic based rate-control method which is based on very low bit rate video coding standards H.263 plus, applied on very low bit rate applications. Previous rate control methods control the generated bit rates by setting the optimum quantization parameters per macro block unit on frame. But, in this paper, we added the pre-processing algorithm, semantic region recognition and assignment of priority algorithm, to obtain the subjective quality enhancement. This work aims to improve the subjective quality of skin color region or face by using unimportant background region's bit resources.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.2
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• pp.99-114
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• 2020

The characteristics of the Brazilian tensile strengths(σ_t) parallel to the rock cleavages in Jurassic granite from Geochang were analysed. The evaluation for the six directions of rock cleavages was performed using the parameter values on microcrack length and the above strength. The strength values of the five test specimens belonging to each direction were classified into five groups. The strength values of these five groups increase in order of group A < B < C < D < E. The close dependence between the above microcrack and strength was derived. The analysis results of this study are summarized as follows. First, the chart showing the variation and characteristics of strength among the three rock cleavages were made. In the above chart, the strength values of six directions belonging to each group were arranged in order of rift(R1 and R2), grain(G1 and G2) and hardway(H1 and H2). The strength distribution lines of the five groups concentrate in the direction of R1. And the widths among the above five lines indicating strength difference(Δσ_t) are the most narrowest in R1 direction. From the related chart, the variation characteristics among the two directions forming each rock cleavage were derived. G2(2)-test specimen shows higher value and lower value of the difference in strength compared to the case of G1(1)-test specimen. These kinds of phenomena are the same as the case between the test specimen H2(2) and H1(1). The strength characteristics of the above test specimens (2) suggest lower microcrack density value and higher degree of uniformity in the distribution of microcracks arrayed parallel to the loading direction compared to those of test specimens (1). The six strength values belonging to each group were arranged in increasing order in the above chart. The strength values of the test specimens belonging to both group D and E appear in order of R1 < R2 < G1 < H1 < G2 < H2. Therefore, the strength values of group D and E can be indicator values for evaluating the six directions of rock cleavages. Second, the correlation chart between slope angle(θ) and strength difference(Δσ_t) were made. The values of the above two parameters were obtained from the five strength distribution lines connecting between the two directions. From the chart related to rift plane(G1-H1, R'), grain plane(R1-H2, G') and hardway plane(R2-G2, H'), the slope values of linear functions increase in order of R'(0.391) < G'(0.470) < H'(0.485). Among three planes, the charts related to hardway plane show the highest distribution density among the five groups. From the related chart for rift(R1-R2, R), grain(G1-G2, G) and hardway(H1-H2, H), the slope values of linear functions increase in order of rift(0.407) < hardway(0.453) < grain(0.460). Among three rock cleavages, the charts related to rift show the highest frequency of groups belonging to the lower region. Taken together, the width of distribution of the slope angle among the three planes and three rock cleavages increase in order of H' < G < R' < R < G' < H. Third, the correlation analysis among the parameters related to microcrack length and the tensile strengths was performed. These parameters may include frequency(N), total length(Lt), mean length(Lm), median length(Lmed) and density(ρ). The correlation charts among individual parameters on the above microcrack(X) and corresponding five levels of tensile strengths for the five groups(Y) were made. From the five kinds of correlation charts, the values of correlation coefficients(R²) increase along with the five levels of strengths. The mean values of the five correlation coefficients from each chart increase in order of 0.22(N) < 0.34(Lt) < 0.38(ρ) < 0.57(Lmed) < 0.58(Lm). Fourth, the correlation chart among the corresponding maximum strength for group E(X) and the above five parameters(Y) were made. From the related chart, the values of correlation coefficient increase in order of 0.61(N) < 0.81(Lt) < 0.87(ρ) < 0.93(Lm) < 0.96(Lmed). The two parameters that have the highest correlations are median length with maximum strength. Through the above correlation analysis between microcrack and strength, the credibility for the results from this study can be enhanced.