• Investigative Magnetic Resonance Imaging
• /
• 제23권3호
• /
• pp.220-227
• /
• 2019

Purpose: To evaluate the usefulness of wash-in color map in detecting early enhancement of prostate focal lesion compared to whole dynamic contrast-enhanced MRI (DEC MRI) images. Materials and Methods: This study engaged 50 prostate cancer patients who underwent multiparametric MRI and radical prostatectomy as subjects. An expert [R1] and a trainee [R2] independently evaluated early enhancement and recorded the time needed to review 1) a wash-in color map and 2) whole DCE MRI images. Results: The review of whole DCE images by R1 showed fair agreement with color map by R1, whole images by R2, and color map by R2 (weighted kappa values = 0.59, 0.44, and 0.58, respectively). Both readers took a significantly shorter time to review the color maps as compared to whole images (P < 0.001). Conclusion: A trainee could achieve better agreement with an expert when using wash-in color maps than when using whole DCE MRI images. Also, color maps took a significantly shorter evaluation time than whole images.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
• /
• pp.97-99
• /
• 2003

Lineament density maps can be used for the quantitative evaluation of relationship between lineaments and groundwater occurrence. There are several kinds of lineament density maps including lineament length density, lineament cross-points density, and lineament counts density maps. This paper reports the usefulness of the representative elementary area (REA) concept for lineament analysis. This concept refers to the area size of the unit circle to calculate the lineament density factors distributed within the circle: length, counts and cross-points counts. The circle is a unit circle that calculates the sum of the lineament length, lineament counts and the number of cross-points within it. The REA is needed to obtain the best representative lineament density map prior to the analysis of relation between lineaments and groundwater well yield or other groundwater characteristics. A basic lineament map for the Yongsangang-Seomjingang watershed of Korea, drawn from aerial black-and-white photographs of 1/20, 000 scale was used for demonstrating the concept. From this study, the conclusions were as follows: (1) the REA concept can be efficiently applied to the lineament density analysis and mapping, (2) for whole Yongsangang-Seomjingang watershed which has 6, 502 lineaments with an average lineament length of 3.3 km, the lower limits of each REA used for drawing the three density maps were about 1.77 $\textrm{km}^2$ (r=750 m) for lineament length density, 7.07 $\textrm{km}^2$ (r=1, 500 m) for lineament counts density, and 4.91 $\textrm{km}^2$ (r=1, 250 m) for lineament cross-points density, respectively, (3) the lineament densities are inversely proportional to the size of REA, and the REA can be calculated with this inversely linear regression model, (4) if the average lineament density values for the whole study area are known, the most accurate density maps can be drawn using the REAs obtained from each linear regression model, and (5) but critical attention should be paid to draw lineament counts density and lineament cross-points density maps because.

• 대한수학회논문집
• /
• 제9권2호
• /
• pp.355-359
• /
• 1994

It would be interesting to know if energy minimizing harmonic maps between manifolds have symmetric properties when the manifolds under consideration have some. In this paper, we consider among others radial symmetry. A radially symmetric manifold M of dimension m is the one with a point, called a pole, and an O(m) action as an isometric rotation with respect to the pole, or more precisely a radially symmetric manifold M has a coordinate on which the metric is of the form $ds_{M}$$^2$ = d$r^2$ + m(r)$^2$d$\theta^2$ for some function m(r) depending only on r. Of course m(0) = 0, m'(0) = 1, and when m(r) = r, (M, $ds_{ M}$/$^2$) is the Euclidean space $R^2$.(omitted)

• 대한수학회보
• /
• 제58권4호
• /
• pp.973-981
• /
• 2021

Let R be a commutative ring with identity 1, n ≥ 3, and let 𝒯_n(R) be the linear Lie algebra of all upper triangular n × n matrices over R. A linear map 𝜑 on 𝒯_n(R) is called to be strong commutativity preserving if [𝜑(x), 𝜑(y)] = [x, y] for any x, y ∈ 𝒯_n(R). We show that an invertible linear map 𝜑 preserves strong commutativity on 𝒯_n(R) if and only if it is a composition of an idempotent scalar multiplication, an extremal inner automorphism and a linear map induced by a linear function on 𝒯_n(R).

• Korean Journal of Mathematics
• /
• 제16권3호
• /
• pp.291-300
• /
• 2008

In this paper, we introduce several types of r-semi-generalized fuzzy compactness and fuzzy r-compactness in fuzzy topological spaces and investigate the relations between these compactness.

• Journal of the Korean Data and Information Science Society
• /
• 제23권5호
• /
• pp.971-981
• /
• 2012

구글 지도는 지리 정보를 갖는 데이터에 대한 통계정보를 제공하기 위한 보편화된 수단의 하나로 자리매김하고 있다. 본 연구에서는 R에서 구글 지도를 활용하는 방법에 대해 소개하고, 구글 지도상에 다양한 통계그래프를 표현하기 위한 R 함수를 개발한다. 개발된 함수를 통하여 막대그래프, 원형그래프, 사각형그래프 등과 같은 다양한 통계그래프를 지도상에 표현할 수 있다.

• Kyungpook Mathematical Journal
• /
• 제62권1호
• /
• pp.43-55
• /
• 2022

Let R be a *-ring and n ≥ 1 be an integer. The objective of this paper is to introduce the notion of n-skew centralizing maps on *-rings, and investigate the impact of these maps. In particular, we describe the structure of prime rings with involution '*' such that _*[x, d(x)]_n ∈ Z(R) for all x ∈ R (for n = 1, 2), where d : R → R is a nonzero derivation of R. Among other related results, we also provide two examples to prove that the assumed restrictions on our main results are not superfluous.

• Korean Journal of Mathematics
• /
• 제8권1호
• /
• pp.91-96
• /
• 2000

• 호남수학학술지
• /
• 제35권4호
• /
• pp.757-764
• /
• 2013

In this paper, we give sufficient conditions for a map with nonconvex values to have a continuous selection and the selection extension property in LC-metric spaces under the one-point extension property. And we apply it to weakly lower semicontinuous maps and generalize previous results. We also get a continuous selection theorem for almost lower semicontinuous maps with closed sub-admissible values in $\mathbb{R}$-trees.

• 한국지능시스템학회논문지
• /
• 제21권4호
• /
• pp.506-511
• /
• 2011

In this paper we investigate some situations in connection with two exact sequences of fuzzy linear maps. Also we obtain a generalization of the work [Theorem4] of Pan [5], and we study the analogies of The Four Lemma and The Five Lemma of homological algebra. Finally we obtain a special exact sequence.