• Journal of Ginseng Research
• /
• 제42권2호
• /
• pp.199-207
• /
• 2018

Background: Ginseng is a well-known traditional Chinese medicine that has been widely used in a range of therapeutic and healthcare applications in East Asian countries. Microbial transformation is regarded as an effective and useful technology in modification of nature products for finding new chemical derivatives with potent bioactivities. In this study, three minor derivatives of ginsenoside compound K were isolated and the inducing effects in the Wingless-type MMTV integration site (Wnt) signaling pathway were also investigated. Methods: New compounds were purified from scale-up fermentation of ginsenoside Rb1 by Paecilomyces bainier sp. 229 through repeated silica gel column chromatography and high pressure liquid chromatography. Their structures were determined based on spectral data and X-ray diffraction. The inductive activities of these compounds on the Wnt signaling pathway were conducted on MC3T3-E1 cells by quantitative real-time polymerase chain reaction analysis. Results: The structures of a known 3-keto derivative and two new dehydrogenated metabolites were elucidated. The crystal structure of the 3-keto derivative was reported for the first time and its conformation was compared with that of ginsenoside compound K. The inductive effects of these compounds on osteogenic differentiation by activating the Wnt/b-catenin signaling pathway were explained for the first time. Conclusion: This study may provide a new insight into the metabolic pathway of ginsenoside by microbial transformation. In addition, the results might provide a reasonable explanation for the activity of ginseng in treating osteoporosis and supply good monomer ginsenoside resources for nutraceutical or pharmaceutical development.

• 한국정보통신학회논문지
• /
• 제11권4호
• /
• pp.793-799
• /
• 2007

제안된 방법은 다른 이미지 서브트랙션 방법에 대하여 커다란 성능향상을 보임을 일련의 실험들을 통하여 보여준다. 일반적으로 수 마이크로 단위로 계측되는 반도체의 검사 정밀도를 높이기 위해서는 라인스캔 카메라가 이용된다. 그러나 불량 검사는 스캔속도와 조명조건에 매우 민감하기 때문에 정확한 경계검출 알고리즘이 필요하다. 본 논문에서는 반도체 칩의 범프 불량 검출의 정확성을 높이기 위해서 서브픽셀을 적용한 경계 검출을 제안하였다. 범프 에지는 범프 중심점에서 네 방향으로 1차 도함수에 의해서 검출되고 서브픽셀 방법으로 정확한 에지 위치를 찾는다. 그리고 범프 돌기, 범프 브리지, 범프 변색에 의해 범프 크기 가 변할 수 있기 때문에 에러를 최소화 하기 위해서 최소자승법을 이용하여 정확한 범프 경계를 구한다. 실험 결과 제안된 방법은 기존의 다른 경계 검출 알고리즘에 비하여 커다란 성능향상을 보였다.

• 해양환경안전학회:학술대회논문집
• /
• 해양환경안전학회 2005년도 추계학술대회지
• /
• pp.197-202
• /
• 2005

일반적으로 수 마이크로 단위로 계측되는 반도체의 검사 정밀도를 높이기 위해서는 라인스캔 카메라가 이용된다. 그러나 불량 검사는 스캔속도와 조명조건에 매우 민감하기 때문에 정확한 경계 검출 알고리즘이 필요하다. 본 논문에서는 반도체 칩의 범프 불량 검출의 정확성을 높이기 위해서 서브픽셀을 적용한 경계 검출을 제안하였다. 범프 에지는 범프 중심점에서 네 방향으로 1차 도함수에 의해서 검출되고 서브픽셀 방법으로 정확한 에지 위치를 찾는다. 그리고 범프 돌기, 범프 브리지, 범프 변색에 의해 범프 크기가 변할 수 있기 때문에 에러를 최소화하기 위해서 최소자승법을 이용하여 정확한 범프 경계를 구한다. 실험 결과 제안된 방법은 기존의 다른 경계 검출 알고리즘에 비하여 커다란 성능향상을 보였다.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1991년도 가을 학술발표회 논문집
• /
• pp.57-62
• /
• 1991

For the purpose of developing the method for efficiently calculating the design sensitivity and the reliability for the complicated structure such as ship structure, the probabilistic finite element method is introduced to formulate the deterministic design sensitivity analysis method and incorporated with the second moment reliability methods such as MVFOSM, AFOSM and SORM. Also, the probabilistic design sensitivity analysis needed in the reliability-based design is performed. The reliability analysis is carried out for the initial yielding failure, in which the derivative derived in the deterministic desin sensitivity is used. The present PFEM-based reliability method shows good agreement with Monte Carlo method in terms with the variance of response and the associated probability of failure even at the first or first few iteration steps. The probabilistic design sensitivity analysis evaluates explicitly the contribution of each random variable to probability of failure. Further, the reliability index variation can be easily predicted by the variation of the mean and the variance of the random variables.

• Structural Engineering and Mechanics
• /
• 제36권1호
• /
• pp.19-36
• /
• 2010

The load and resistance factors are generally obtained using the First Order Reliability Method (FORM), in which the design point should be determined and derivative-based iterations have to be used. In this paper, a simple method for estimating the load and resistance factors using the first four moments of the basic random variables is proposed and a simple formula for the target mean resistance is also proposed to avoid iteration computation. Unlike the currently used method, the load and resistance factors can be determined using the proposed method even when the probability density functions (PDFs) of the basic random variables are not available. Moreover, the proposed method does not need either the iterative computation of derivatives or any design points. Thus, the present method provides a more convenient and effective way to estimate the load and resistance factors in practical engineering. Numerical examples are presented to demonstrate the advantages of the proposed fourth moment method for determining the load and resistance factors.

• Korean Journal of Mathematics
• /
• 제16권1호
• /
• pp.57-84
• /
• 2008

In this paper, a boundary control problem for a flow governed by the time-dependent two dimensional Navier-Stokes equations is considered. We derive a mathematical formulation and a relevant process for an appropriate control along the part of the boundary to minimize the drag due to the flow. After showing the existence of an optimal solution, the first order optimality conditions are derived. The strict differentiability of the state solution in regard to the control parameter shall be exposed rigorously, and the necessary conditions along with the system for the optimal solution shall be deduced in conjunction with the evaluation of the first order Gateaux derivative to the performance functional.

• 한국영어학회지:영어학
• /
• 제3권4호
• /
• pp.527-545
• /
• 2003

I look at the respective responsibilities of different components of the language faculty in the description of two radically different kinds of linguistic phenomenon. The first is the production/perception mismatch in the child's acquisition of the phonology of its first language. There is strong evidence that the child's lexical representations are the same as the adult's, but I argue that the child's own pronunciations, have no linguistic status and are best treated as the product of a neural network. The second is the nature of compositionality, where I argue that compositionality in Natural Language is derivative from that in the Language of Thought. With this assumption and using evidence from quantification in ‘backward control’ structures, I argue that chain theory is intrinsically inimical to a simple view of the legibility relation between LF and LoT.

• 한국측량학회지
• /
• 제25권1호
• /
• pp.63-68
• /
• 2007

The computations of an ultra-high degree associated Legendre functions and its first derivative up to degree and order of 10800 are reported. Not only the magnitude of orders for the ultra-high degree calculation is presented but the numerical stability and accuracy of the computed values are described in detail. The accuracy on the order of $10^{-25}\;and\;10^{-15}$ was obtained for the values of Legendre function and the first derivatives of Legendre functions, respectively. The computable highest degree and order of Legendre function in terms of latitudes and the linear relationship between the magnitude of the function with respect to degrees and orders is found. It is expected that the computed Legendre functions contribute in many geodetic and geophysical applications for simulations as well as theoretical verifications.

• 대한조선학회지
• /
• 제19권4호
• /
• pp.19-29
• /
• 1982

Galerkin's finite element method is applied to a two-dimensional heat convection-diffusion problem arising in the hydrodynamic lubrication of thrust bearings used in naval vessels. A parabolized thermal energy equation for the lubricant, and thermal diffusion equations for both bearing pad and the collar are treated together, with proper juncture conditions on the interface boundaries. it has been known that a numerical instability arises when the classical Galerkin's method, which is equivalent to a centered difference approximation, is applied to a parabolic-type partial differential equation. Probably the simplest remedy for this instability is to use a one-sided finite difference formula for the first derivative term in the finite difference method. However, in the present coupled heat convection-diffusion problem in which the governing equation is parabolized in a subdomain(Lubricant), uniformly stable numerical solutions for a wide range of the Peclet number are obtained in the numerical test based on Galerkin's classical finite element method. In the present numerical convergence errors in several error norms are presented in the first model problem. Additional numerical results for a more realistic bearing lubrication problem are presented for a second numerical model.

• 한국CDE학회논문집
• /
• 제4권4호
• /
• pp.312-317
• /
• 1999

An inflection point on a curve is a point where the curvature vanishes. An inflection point is useful for various geometric operations such as the approximation of curves and intersection points between curves or curve approximations. An inflection point on planar Bezier curves can be easily detected using a hodograph and a derivative of hodograph, since the closed from of hodograph is known. In the case of rational Bezier curves, for the detection of inflection point, it is needed to use the first and the second derivatives have higher degree and are more complex than those of non-rational Bezier curvet. This paper presents three methods to detect inflection points of rational Bezier curves. Since the algorithms avoid explicit derivations of the first and the second derivatives of rational Bezier curve to generate polynomial of relatively lower degree, they turn out to be rather efficient. Presented also in this paper is the theoretical analysis of the performances of the algorithms as well as the experimental result.