• Korean Journal of Pharmacognosy
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• v.50 no.3
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• pp.232-238
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• 2019

Phytochemical study of Ganoderma lucidum (Polyporaceae) let to the isolation of five lanostane triterpenoid (1-5), along with two nitrogen derived phenolic compounds, N-phenylethylformamide (6) and N-acetylphenethylamine (7). The structures of the compounds were determined by 1D and 2D NMR, and MS experiments, as well as by comparison of their data with published values. Compounds 6 and 7 were isolated for the first time from the genus Ganoderma and this species. All the compounds were evaluated for cancer chemopreventive potential based on their ability to inhibit nitric oxide (NO) production induced by lipopolysaccharide (LPS) in mouse macrophage RAW 264.7 cells in vitro. Among the isolates, compounds 2 and 3 showed moderate inhibitory activity against NO production.

• Journal of the Korean earth science society
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• v.42 no.1
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• pp.102-117
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• 2021

This study analyzed the learning characteristics of polar education programs operated by polar research institutes in domestic and foreign countries and aims to provide directions for improving domestic polar education programs. Using the database provided by the Korea Polar Research Institute (KOPRI), 120 programs from 16 research institutes in 9nine countries were selected. Each program was analyzed based on educational level, instructor, education period, learning place, learning environment, learning content, and learning method. Significant differences in domestic and foreign programs in terms of instructors, operational methods, educational places, and learning methods were found. Based on these findings, we discuss the direction for improving domestic polar education by expanding the base of polar education, diversifying the learning methods, and systematizing polar education using examples of actual programs. Based on the scientific, social, economic, and cultural values and importance of the polar region, this study presents specific directions to further spread and sustain polar education and culture in Korea.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.675-678
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• 2000

This paper presents a parametric line equation on the log-polar mapped plane to detect the straight lines in an original image. The log-polar edge image used in Hough transform is constructed by combining the edge images of both fovea and periphery. The foveal edge image detected by a Sobel mask on the Cartesian plane is transformed to the log-polar plane by forward mapping but the edge detection of the peripheral region is obtained by directly applying the newly developed mask to the log-polar plane. This paper also proposes a analytic method then determining a border between the fovea and the periphery regions.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.523-526
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• 2000

본 논문에서는 임의의 모양을 가지는 영상 객체(image object)에 적용 가능한 모양적응 이산변환(PSADT : Polar coordinates shape adaptive discrete transform)에 기반한 새로운 워터마킹 기법을 제안한다. 대수-극 좌표계(log-polar coordinates)와 모양적응 이산변환을 이용하여 제안된 기법은 MPEG-4의 VOP와 같은 임의의 모양을 가지는 영상 객체에 적용할 수 있을 뿐만 아니라 기존 기법에 비하여 회전과 크기 변화와 같은 기하학적인 공격에 대하여 우수한 강인성을 제공한다.

• The Pure and Applied Mathematics
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• v.5 no.2
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• pp.133-142
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• 1998

A simple mathematical theory is developed on the periodicity of elementary polar functions. The periodicity plays an important role in efficient plotting of some closed polar curves, without the excessive use of plotting devices and materials. An efficient plotting algorithm utilizing the periodicity is proposed and its implementation by a Mathematica program is introduced for a family of closed polar functions.

• Communications of the Korean Mathematical Society
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• v.20 no.1
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• pp.15-21
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• 2005

Null designs on the poset of dual polar spaces are considered. A poset of dual polar spaces is the set of isotropic subspaces of a finite vector space equipped with a nondegenerate bilinear form, ordered by inclusion. We show that the minimum number of isotropic subspaces to construct a nonzero null t-design is ${\prod}^{t}_{i=0}(1+q^{i})$ for the types $B_N,\;D_N$, whereas for the case of type $C_N$, more isotropic subspaces are needed.

• Communications of the Korean Mathematical Society
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• v.32 no.4
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• pp.1077-1097
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• 2017

In this research article, we introduce certain concepts, including domination, total domination, strong domination, weak domination, edge domination and total edge domination in m-polar fuzzy graphs. We describe these concepts by several examples. We investigate some related properties of certain dominations in m-polar fuzzy graphs. We also present a decision making method based on domination in m-polar fuzzy graphs.

• Proceedings of the Korean Quaternary Association Conference
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• 2006.06a
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• pp.35-38
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• 2006

• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.434-435
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• 2007

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• Proceedings of the Mineralogical Society of Korea Conference
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• 2004.05a
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• pp.32-34
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• 2004