• Kyungpook Mathematical Journal
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• 제59권3호
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• pp.505-513
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• 2019

In this paper, we study orthanogonal polynomials by looking at their comrade matrices and reachability matrices. First, we focus on the algebraic structure that is exhibited by comrade matrices. Then, we explain some properties of this algebraic structure which helps us to find a connection between comrade matrices and reachability matrices. In the last section, we use this connection to determine the determinant, eigenvalues, and eigenvectors of these matrices. Finally, we derive a factorization for det R(A, x), where R(A, x) is the reachability matrix for a comrade matrix A and x is a vector of indeterminates.

• 품질경영학회지
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• 제29권1호
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• pp.1-10
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• 2001

We consider the problem of detecting special variations in multivariate $T^2$-control chart when two or more multivariate outliers are present. Since a multivariate outlier may reflect slippage in mean, variance, or correlation, it can distort the sample mean vector and sample covariance matrix. Damaged sample mean vector and sample covariance matrix have difficulty in examining special variations clearly, An alternative to detection outliers or special variations is to use robust estimators of mean vector and covariance matrix that are less sensitive to extreme observations than are the standard estimators $\bar{x}$ and $\textbf{S}$. We applied popular minimum volume ellipsoid(MVE) and minimum covariance determinant(MCD) method to estimate mean vector and covariance matrix and compared its results with standard $T^2$-control chart using simulated multivariate data with outliers. We found that the modified $T^2$-control chart based on the above robust methods were more effective in detecting special variations clearly than the standard $T^2$-control chart.

• 한국통신학회논문지
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• 제13권4호
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• pp.302-308
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• 1988

본 논문에서는 벡터 양자화(VQ)의 탐색 복잡도를 줄이기 위한 방법을 제안한다. 본 방법의 현재 부호화하려는 벡터의 특성을 효율적으로 이용함으로써 고속 탐색 효과를 가져온다. 벡터 크기가 16인 제안하는 VQ방식으로써 약 0.1-1.9dB의 미소한 성능 감소로 1/8-1/16의 복잡도 감소를 꾀할 수 있음을 보인다. 동시에 기존의 방식과 비교하여 더 성능이 우수함을 보인다.

• 한국컴퓨터정보학회논문지
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• 제16권4호
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• pp.1-13
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• 2011

본 논문에서는 MHI(Motion History Image)의 형태학적 정보를 이용하여 동작을 인식하는 제스처 인식(Gesture Recognition) 시스템을 제안한다. 입력되는 영상으로부터 동작에 관한 정보를 제공하는 MHI를 획득하고, 이 MHI로부터 x, y 각각의 좌표에 대한 기울기(gradient) 영상을 추출한다. 각각의 기울기 영상에 형태 문맥기법(shape context method)을 적용하여 형태 정보를 추출하고, 추출된 형태 정보 값들을 특징 값으로 사용한다. 이렇게 획득한 특징값들을 최종적으로 SVM(Support Vector Machine) 분류기로 학습 및 분류하여 동작을 인식한다. 제안하는 시스템은 MHI의 형태학적인 정보들을 사용함으로써 동작의 방향성을 인식할수 있고 다수 사람의 동작 인식이 가능하다. 뿐만 아니라 간단한 특징 추출 방법으로 높은 인식률의 시스템을 구현하였다.

• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.356-365
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• 2004

In analyzing the region of the Amycolatopsis mediterranei S699 chromosome responsible for the biosynthesis of the ansamycin antibiotic rifamycin, we identified a gene, designated orj0, which is located immediately upstream of the rifamycin polyketide synthase (PKS). Orj0 encodes a protein, on the basis of sequence-comparative analysis, that is similar to several cytochrome P450 monooxygenases from different sources. The rifamycin producer, A. mediterranei, predominantly produces rifamycin B from its macrocyclic intermediate, proansamycin X, through dehydrogenation and hydroxylation steps. However, an A. mediterranei strain, deleted in orj0 by gene replacement, no longer produced rifamycin B. Furthermore, a versatile replicative vector in A. mediterranei was constructed and rifamycin B production was restored in a complementation experiment of orj0 using this novel vector. These consecutive results verified that the arf0 protein, which is a P450 hydroxylase, is required for the production of rifamycin B in A. mediterranei.

• 천문학회보
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• 제39권1호
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• pp.69.1-69.1
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• 2014

We perform an MHD simulation combined with observed vector field data to clarify an eruptive dynamics in the solar flare. We first extrapolate a 3D coronal magnetic field under a Nonlinear Force-Free Field (NLFFF) approximation based on the vector field, and then we perform an MHD simulation where the NLFFF prior to the flare is set as an initial condition. Vector field was obtained by the Soar Dynamics Observatory (SDO) at 00:00 UT on February 15, which is about 90 minutes before the X2.2-class flare. As a result, the MHD simulation successfully shows an eruption of strongly twisted lines whose values are over one-turn twist, which are produced through the tether-cut magnetic reconnection in strongly twisted lines of the NLFFF. Eventually, we found that they exceed a critical height at which the flux tube becomes unstable to the torus instability determining the condition that whether a flux tube might escape from the overlying field lines or not. In addition to these, we found that the distribution of the observed two-ribbon flares is similar to the spatial variance of the footpoints caused by the reconnection of the twisted lines being resided above the polarity inversion line. Furthermore, because the post flare loops obtained from MHD simulation well capture that in EUV image taken by SDO, these results support the reliability of our simulation.

• East Asian mathematical journal
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• 제40권1호
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• pp.1-23
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• 2024

Let M be a semi-invariant submanifold of codimension 3 with almost contact metric structure (𝜙, 𝜉, 𝜂, g) in a complex space form M_n+1(c). We denote by A, K and L the second fundamental forms with respect to the unit normal vector C, D and E respectively, where C is the distinguished normal vector, and by R_𝜉 = R(𝜉, ·)𝜉 the structure Jacobi operator. Suppose that the third fundamental form t satisfies dt(X, Y) = 2𝜃g(𝜙X, Y) for a scalar 𝜃(≠ 2c) and any vector fields X and Y , and at the same time R_𝜉K = KR_𝜉 and ∇_{𝜙∇𝜉𝜉}R_𝜉 = 0. In this paper, we prove that if it satisfies ∇_𝜉R_𝜉 = 0 on M, then M is a real hypersurface of type (A) in M_n(c) provided that the scalar curvature $\bar{r}$ of M holds $\bar{r}-2(n-1)c{\leq}0$.

• 대한수학회보
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• 제46권2호
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• pp.255-261
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• 2009

In this paper, we shall prove several results concerning Ricci curvature of a Riemannian manifold (M, g) := (SU(2), g) with an arbitrary given left invariant metric g. First of all, we obtain the maximum (resp. minimum) of {r(X) := Ric(X,X) | ${||X||}_g$ = 1,X ${\in}$ X(M)}, where Ric is the Ricci tensor field on (M, g), and then get a necessary and sufficient condition for the Levi-Civita connection ${\nabla}$ on the manifold (M, g) to be projectively flat. Furthermore, we obtain a necessary and sufficient condition for the Ricci curvature r(X) to be always positive (resp. negative), independently of the choice of unit vector field X.

• Communications for Statistical Applications and Methods
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• 제13권2호
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• pp.243-254
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• 2006

The relative frequency of order statistics is investigated for independent and identically distributed (i.i.d.) random variables. Specifically, it is shown that the probability $Pr\{X_{[s]}=x\}$ is no less than the probability $Pr\{X_{[r]}=x\}$ at any point $x{\geqq}x_0$ when r$X_{[r]}$ denotes the r-th order statistic of an i.i.d. discrete random vector and $x_0$ depends on the population probability distribution. A similar result for i.i.d. continuous random vectors is also presented.

• 한국식품영양학회지
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• 제9권2호
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• pp.123-136
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• 1996

IPSKCDNA gene(1.8 kbp) encoding rat brain IP3K enzyme contained Not I restric site in open reading frame. The Not I sequence, GCGGCCGC, was converted to GCAGCCGC by site-directed mutagenesis. The mutated IP3KcDNA was digested with EcoR I and ligated with EcoR I-restricted psp72·Not2 vector. The resulting psp72 · Not2-IP3KCDNA was digested with the Not I restriction enzyme and then subcloned into the Not I -digested PZIP · NeoSV(X) mammalian expression vector. The PZIP · NeoSV(X) -IPSKCDNA was transfected into CCL39 hamster lung fibroblast cells. The efficiency of the expressed IPSKCDNA gene was significantly higher than expected generally, not only a mean 5-fold increase in the amount of enzyme, but also 16-fold increase in enzyme activity from tractsfected CCL39 cells by the method of Western blot using anti-lP3K antibodies. Both distribution of IPSK in various rat tissues and biochemical properties were discussed.