• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.2093-2096
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• 2014

2H-azirine, a less known acetonitrile isomer, is observed in matrix IR spectra from the precursor exposed to radiation from laser ablation of transition-metals. Its vibrational characteristics confirm the previous results, and those for the deuterated and $^{13}C$ substituted isotopomers are also newly reported. The weak absorptions are traced to the low production yield due to its high energy and low extinction constants. IRC computations reveal smooth inter-conversion between 2H-azirine and $CH_2NCH$, providing a rationale for the observed variation of their relative contents during photolysis.

• 대한전자공학회논문지SD
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• 제45권1호
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• pp.43-49
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• 2008

본 논문에서는 Ant Colony Optimization(ACO)을 이용하여 Single-Error Correcting & Double-Error Detecting(SEC-DED)을 제공하는 메모리 ECC 체커 회로의 소비전력을 절감하는 방안을 제시한다. H-매트릭스를 통해 구현되는 SEC-DED 코드인 Hsiao 코드의 대칭성과 H-매트릭스 구성상의 높은 자유도를 이용하여 회로의 면적, 딜레이에 영향을 주지 않고 최소의 비트 트랜지션이 일어나도록 H-매트릭스를 최적화한다. 실험을 통하여 H-매트릭스의 최적화를 위한 ACO 매핑과 파라메터의 설정을 알아보고 이의 구현 결과를 랜덤 매트릭스 구성을 통한 방식 및 기존의 GA알고리즘을 이용한 최적화 방식과 비교하여 소비 전력이 기존의 방식에 비해 절감될 수 있음을 보여준다.

• 대한화학회지
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• 제40권9호
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• pp.640-648
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• 1996

Chitin을 epichlorohydrin과 반응시켜 가교 chitin을 합성하고, $C_2$ 위치의 아세트아미드기를 탈아세틸화하여 가교 chitosan을 얻었다. 가교 chitosan을 증류수에 팽윤시킨 다음 글리세린과 silver sulfadiazine을 가하여 고분자 matrix를 제조하였다. 이렇게 제조된 matrix로부터 in vitro에서의 약물 방출 pattern을 고찰하기 위해 pH7.4 인산염 완충용액 중에서 약물의 함유량, 글리세린의 농도 변화 및 matrix 두께변화에 미치는 인자들에 관하여 연구 검토 하였다. 고분자 matrix내의 약물의 함유량과 matrix의 두께가 증가할수록 약물 방출 지속 시간은 지연되었다. 그러나 글리세린의 함유량이 증가함에 따라 약물 방출 지속 시간은 오히려 감소 하였다. 또한 약물의 함유량과 글리세린의 함유량이 증가할수록 겉보기 방출속도상수 (K)값도 증가하였으나, matrix 두께가 증가함에 따라서는 겉보기 방출속도상수(K)값이 일정하였다. 이상과 같이 가교 chitosan은 약품의 방출 조절형 제제로서 사용 가능성을 나타냈으며, 약물로 사용된 silver sulfadiazine의 방출거동은 Higuchi model에 따른 확산으로 생각되었다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제20권2호
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• pp.107-121
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• 2016

We analyze the complexity of the LLL algorithm, invented by Lenstra, Lenstra, and $Lov{\acute{a}}sz$ as a a well-known lattice reduction (LR) algorithm which is previously known as having the complexity of $O(N^4{\log}B)$ multiplications (or, $O(N^5({\log}B)^2)$ bit operations) for a lattice basis matrix $H({\in}{\mathbb{R}}^{M{\times}N})$ where B is the maximum value among the squared norm of columns of H. This implies that the complexity of the lattice reduction algorithm depends only on the matrix size and the lattice basis norm. However, the matrix structures (i.e., the correlation among the columns) of a given lattice matrix, which is usually measured by its condition number or determinant, can affect the computational complexity of the LR algorithm. In this paper, to see how the matrix structures can affect the LLL algorithm's complexity, we derive a more tight upper bound on the complexity of LLL algorithm in terms of the condition number and determinant of a given lattice matrix. We also analyze the complexities of the LLL updating/downdating schemes using the proposed upper bound.

• 한국통신학회논문지
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• 제40권2호
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• pp.372-379
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• 2015

최근 동영상 압축 표준은 세밀한 움직임 정보를 확보하기 위해 1/4 화소 단위의 움직임 예측 알고리즘을 사용하고 있다. 일반적인 동영상 부호화기에서 사용하는 공간 영역에서의 움직임 예측은 부화소 단위 움직임 예측을 위한 보간 기술의 적용으로 인한 계산량 증가 문제가 발생한다. 본 논문에서는 주파수 영역에서 shifting matrix를 이용한 부화소 정밀도의 움직임 예측 알고리즘을 제안한다. 주파수 영역에서 shifting matrix 알고리즘을 사용함으로써 낮은 계산량으로 부화소 움직임 예측을 수행할 수 있었으며, 실험 결과 공간 영역에서의 움직임 예측 알고리즘에 비해 낮은 비트량과 높은 PSNR(peak signal-to-noise ratio)을 제공함을 확인하였다.

• Transactions on Control, Automation and Systems Engineering
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• 제2권3호
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• pp.163-168
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• 2000

The problems of mixed $H_2/H_{\infty}$ filtering design fer continuous and discrete time linear systems with time delay are investigated. The main purpose is to design a stable mixed $H_2/H_{\infty}$ filter which minimizes the H$_2$Performance measure satisfying a prescribed H$_{\infty}$ norm bound on the closed loop system in continuous-time case and discrete-time case, respectively. The sufficient conditions of existence of filter, the mixed $H_2/H_{\infty}$ filter design method, and the upper bound of performance measure are proposed by LMI(linear matrix inequality) techniques in terms of all finding variables. Also, we present optimization problems in order to get the optimal mixed $H_2/H_{\infty}$ filter in continuous and discrete time case, respectively.

• 한국응용과학기술학회지
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• 제32권2호
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• pp.326-329
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• 2015

This study is to develop the double capsulation technology in order to increase the conservativeness and stability of unstable materials such as vitamins, polyphenols, natural active ingredients. And also, best way of triple matrix capsulation using natural polymers were detail described. As the first capsulation with w/o/w (water-in-oil-in-water) emulsifying system, our study group was especially made to soft and moisture cream using 5wt% of sucrose ester emulsifier as first capsulation. Nutrient agents are squalane, camellia oil. Triple matrix capsulation was formed with the best stabilized bead type capsules when it blended of chitosan, algin, sodium-potassium alginate. The bead diameter size was about 2.0~4.5mm (mean diameter: 3.2mm). Activity of lactobacillus containing cream for depending on various pH variations showed that alkalinity ($pH=10.8{\pm}0.5$) condition was higher than acidity ($pH=4.2{\pm}0.2$) and neutrality ($pH=7.1{\pm}0.3$) conditions. After a month, it also was certified to the activity of lactobacillus in incubated at $37{\pm}1^{\circ}C$ in culture medium. As application of food industry, we developed the containing lactobacillus capsule and 7 colored kinds of double and triple matrix capsulation in yogurt cream and active ingredients. As for above mentioned those results, one of tool to stabilize the living lactobacillus, doubled matrix capsulation greatly be expected to contribute to food industry. Furthermore, it can be expected to apply the drug delivery system (DDS) to active ingredients of stabilizing technologies at drug, pharmaceutical division and cosmetic industry, etc.

• Journal of applied mathematics & informatics
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• 제22권1_2호
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• pp.169-180
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• 2006

We study convergence of multisplitting method associated with a block diagonal conformable multisplitting for solving a linear system whose coefficient matrix is a symmetric positive definite matrix which is not an H-matrix. Next, we study the validity of m-step multisplitting polynomial preconditioners which will be used in the preconditioned conjugate gradient method.

• Journal of applied mathematics & informatics
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• 제23권1_2호
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• pp.337-344
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• 2007

In this paper, we obtain some new bounds for Perron root of a nonnegative matrix, which are expressed by easily calculated function in element of matrix. These new results generalize and improve the bounds of G. Frobenius [1] and H. Minc [2], and also extend the known results by Liu [6].

• 소성∙가공
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• 제8권3호
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• pp.259-259
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• 1999

TiC ceramic particulate-reinforced titanium matrix composites were fabricated and the resultant densification, microstructure, and static and dynamic mechanical properties were studied. Comparing Ti with TiH₂powders as host materials for TiC ceramic reinforcement by pressureless vacuum sintering, TiH₂-started composites showed better sinterability and resistance to both elastic and plastic deformation than Ti-started ones. When TiH₂and TiH₂-45 vol.%TiC samples were hot pressed, TiH₂matrices transformed to alpha prime Ti and alpha Ti phase, respectively. It is interpreted that the diffusion of an alpha stabilizer carbon from TiC into the matrix is one of the plausible reasons far such a microstructural difference. The 0.2% offset yield strengths of the hot pressed TiH₂and TiH₂-45 vol.%TiC samples were 1008 and 1446 MPa, respectively, in a static compressive mode (strain rate of 1×$10^{-3}$/s). Dynamic compressive strengths of the samples were 1600 and 2060 MPa, respectively, at a strain rate of 4×10³/s.