• Journal of the Korean Applied Science and Technology
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• v.20 no.1
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• pp.33-43
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• 2003

$LiMn_2O_4$ catalyst for $CO_2$ decomposition was synthesized by oxidation method for 30 min at 600$^{\circ}C$ in an electric furnace under air condition using manganese(II) nitrate $(Mn(NO_3)_2{\cdot}6H_2O)$, Lithium nitrate ($LiNO_3$) and Urea $(CO(NH_2)_2)$. The synthesized catalyst was reduced by $H_2$ at various temperatures for 3 hr. The reduction degree of the reduced catalysts were measured using the TGA. And then $CO_2$ decomposition rate was measured using the reduced catalysts. Phase-transitions of the catalysts were observed after $CO_2$ decomposition reaction at an optimal decomposition temperature. As the result of X-ray powder diffraction analysis, the synthesized catalyst was confirmed that the catalyst has the spinel structure, and also confirmed that when it was reduced by $H_2$, the phase of $LiMn_2O_4$ catalyst was transformed into $Li_2MnO_3$ and $Li_{1-2{\delta}}Mn_{2-{\delta}}O_{4-3{\delta}-{\delta}'}$ of tetragonal spinel phase. After $CO_2$ decomposition reaction, it was confirmed that the peak of $LiMn_2O_4$ of spinel phase. The optimal reduction temperature of the catalyst with $H_2$ was confirmed to be 450$^{\circ}C$(maximum weight-increasing ratio 9.47%) in the case of $LiMn_2O_4$ through the TGA analysis. Decomposition rate(%) using the $LiMn_2O_4$ catalyst showed the 67%. The crystal structure of the synthesized $LiMn_2O_4$ observed with a scanning electron microscope(SEM) shows cubic form. After reduction, $LiMn_2O_4$ catalyst became condensed each other to form interface. It was confirmed that after $CO_2$ decomposition, crystal structure of $LiMn_2O_4$ catalyst showed that its particle grew up more than that of reduction. Phase-transition by reduction and $CO_2$ decomposition ; $Li_2MnO_3$ and $Li_{1-2{\delta}}Mn_{2-{\delta}}O_{4-3{\delta}-{\delta}'}$ of tetragonal spinel phase at the first time of $CO_2$ decomposition appear like the same as the above contents. Phase-transition at $2{\sim}5$ time ; $Li_2MnO_3$ and $Li_{1-2{\delta}}Mn_{2-{\delta}}O_{4-3{\delta}-{\delta}'}$ of tetragonal spinel phase by reduction and $LiMn_2O_4$ of spinel phase after $CO_2$ decomposition appear like the same as the first time case. The result of the TGA analysis by catalyst reduction ; The first time, weight of reduced catalyst increased by 9.47%, for 2${\sim}$5 times, weight of reduced catalyst increased by average 2.3% But, in any time, there is little difference in the decomposition ratio of $CO_2$. That is to say, at the first time, it showed 67% in $CO_2$ decomposition rate and after 5 times reaction of $CO_2$ decomposition, it showed 67% nearly the same as the first time.

• ETRI Journal
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• v.35 no.5
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• pp.880-888
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• 2013

The preexisting pairings ate, $ate_i$, R-ate, and optimal-ate use q-expansion, where q is the size of the defining field for the elliptic curves. Elliptic curves with small embedding degrees only allow a few of these pairings. In such cases, efficiently computable endomorphisms can be used, as in [11] and [12]. They used the endomorphisms that have characteristic polynomials with very small coefficients, which led to some restrictions in finding various pairing-friendly curves. To construct more pairing-friendly curves, we consider ${\mu}$-expansion using the Gallant-Lambert-Vanstone (GLV) decomposition method, where ${\mu}$ is an arbitrary integer. We illustrate some pairing-friendly curves that provide more efficient pairing from the ${\mu}$-expansion than from the ate pairing. The proposed method can achieve timing results at least 20% faster than the ate pairing.

• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.281-288
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• 1994

In this paper, a new decomposition method of the interference EMG signal using MAMDF filtering and digital signal processor. The efficient software and hardware signal processing techniques are employed. The MAMDF filter is employed in order to estimate the presence and likely location of the respective templates which may include in the observed mixture, and high-resolution waveform alignment is employed in order to provide the optimal combination set and time delays of the selected templates. The TMS320C25 digital signal processor chip is employed in order to execute the intensive calculation part of the software. The method is verified through a simulation with real templates which are obtain ed from needle EMG. As a result, the proposed method provides an overall speed improvement of 32-40 times.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1271-1275
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• 1987

With the stochastic process which consists of the harmonic sinusoid and the white nosie, the power spectrum of background EEG is estimated by the Pisarenko Harmonic Decomposition. The estimating results are examined and compared with the results from the maximum entropy spectral estimation, and the optimal order of this model can be determined from the eigen value's fluctuation of autocorrelation of background EEG. From the comparing results, this paper ensures that this method is possible to analyze the power spectrum of background EEG.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.105-107
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• 2002

This paper provides calculation and decomposition of Bus Incremental Cost on Power System Operation. In this method we show deriving Shadow Price from state variables in Optimal condition. And the decomposition can give a detailed description of each Bus Incremental Cost. The proposed method is applied to IEEE-30 and results shows the effectiveness of the method.

• Proceedings of the Safety Management and Science Conference
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• 2012.04a
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• pp.421-433
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• 2012

The objective of this study is to obtain the optimal process condition and the maximum decomposition efficiency by measuring the decomposition efficiency, electricity consumption, and voltage in accordance with the change of the process variables such as the frequency, maintaining time period, concentration, electrode material, thickness of the electrode, the number of windings of the electrode, and added materials etc. of the harmful atmospheric contamination gases such as NO, $NO_2$, and $SO_2$etc. with the plasma which is generated by the discharging of the specially designed and manufactured $TiO_2$ catalysis reactor and SPCP reactor.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.245-252
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• 2010

This paper proposes a constrained multi-area dispatch scheduling algorithm applicable to interconnected power system operations. The dispatch scheduling formulated as an MIP problem can be efficiently computed by GBD algorithm. GBD guarantees adequate computation speed and solution convergence by reducing the dimension of the dispatch scheduling problem. In addition, the regional decomposition technique based on ADM is introduced to obtain efficient inter-temporal OPF solution. It can find the most economic dispatch schedule incorporating power transactions without each regional utility's private information open.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.171-174
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• 2010

적절한 근사화 과정을 통하여 구축된 축소 시스템은 전체 시스템의 거동을 적은 수의 정보를 통하여 효과적으로 표현할 수 있다. 효과적인 시스템 축소를 위하여 본 연구에서는 주파수 영역 Karhunen-Loeve (Frequency-domain Karhunen-Loeve, FDKL) 기법과 시스템 등가 확장 축소 과정(System equivalent expansion reduction process, SEREP)을 연동한 축소 기법을 제안한다. 적합직교분해(Proper orthogonal decomposition)의 한 방법인 FDKL기법을 통하여 최적모드(Optimal mode)를 구하고 이에 SEREP을 적용하여 자유도 변환 행렬을 구한다. 이때 주자유도 선정은 2단계 축소기법을 적용한다. 최종적으로 제안된 기법은 수치예제를 통하여 검증한다.

• Journal of Information Processing Systems
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• v.13 no.4
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• pp.863-875
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• 2017

The traditional text similarity measurement methods based on word frequency vector ignore the semantic relationships between words, which has become the obstacle to text similarity calculation, together with the high-dimensionality and sparsity of document vector. To address the problems, the improved singular value decomposition is used to reduce dimensionality and remove noises of the text representation model. The optimal number of singular values is analyzed and the semantic relevance between words can be calculated in constructed semantic space. An inverted index construction algorithm and the similarity definitions between vectors are proposed to calculate the similarity between two documents on the semantic level. The experimental results on benchmark corpus demonstrate that the proposed method promotes the evaluation metrics of F-measure.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1545-1550
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• 2021

We propose an optimal variable step size adjustment method for the simplified subband affine projection algorithm (Simplified SAP; SSAP) in a subband structure based on a polyphase decomposition technique. The proposed method provides an optimal step size derived to minimize the mean square deviation(MSD) at the time of updating the coefficients of the subband adaptive filter. Application of the proposed optimal step size in the SSAP algorithm using colored input signals ensures fast convergence speed and small steady-state error. The results of computer simulations performed using AR(2) signals and real voices as input signals prove the validity of the proposed optimal step size for the SSAP algorithm. Also, the simulation results show that the proposed algorithm has a faster convergence rate and good steady-state error compared to the existing other adaptive algorithms.