• 충청수학회지
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• 제29권2호
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• pp.347-359
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• 2016

In this paper, we show that the solutions to perturbed functional differential system $$y^{\prime}=f(t,y)+{\int_{t_0}^{t}}g(s,y(s),Ty(s))ds$$, have a bounded properties. To show the bounded properties, we impose conditions on the perturbed part ${\int_{t_0}^{t}}g(s,y(s),Ty(s))ds$ and on the fundamental matrix of the unperturbed system y' = f(t, y) using the notion of $t_{\infty}$-similarity.

• 충청수학회지
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• 제21권3호
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• pp.395-401
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• 2008

In this paper we investigate h-stability for linear dynamic equations on time scales under $u_{\infty}$-similarity.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제22권2호
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• pp.145-158
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• 2015

In this paper, we investigate h-stability and boundedness for solutions of the functional perturbed differential systems using the notion of t_∞-similarity.

• 대한원격탐사학회지
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• 제40권2호
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• pp.167-177
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• 2024

With advancements in satellite technology, interest in target detection and identification is increasing quantitatively and qualitatively. Synthetic Aperture Radar(SAR) images, which can be acquired regardless of weather conditions, have been applied to various areas combined with machine learning based detection algorithms. However, conventional studies primarily focused on the detection of stationary targets. In this study, we proposed a method to identify moving targets using an algorithm that integrates sub-aperture SAR images and cosine similarity calculations. Utilizing a transformer-based deep learning target detection model, we extracted the bounding box of each target, designated the area as a region of interest (ROI), estimated the similarity between sub-aperture SAR images, and determined movement based on a predefined similarity threshold. Through the proposed algorithm, the quantitative evaluation of target identification capability enhanced its accuracy compared to when training with the targets with two different classes. It signified the effectiveness of our approach in maintaining accuracy while reliably discerning whether a target is in motion.

• Journal of applied mathematics & informatics
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• 제31권1_2호
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• pp.277-284
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• 2013

In this paper, we investigate $h$-stability of the nonlinear perturbed difference system via $n_{\infty}$-similarity.

• Korean Journal of Mathematics
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• 제24권4호
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• pp.723-736
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• 2016

This paper shows that the solutions to nonlinear perturbed differential system $$y^{\prime}= f(t,y)+{\int_{t_{0}}^{t}g(s,y(s))ds+h(t,y(t),Ty(t))$$ have bounded properties. To show the bounded properties, we impose conditions on the perturbed part ${\int_{t_{0}}^{t}g(s,y(s))ds,\;h(t, y(t),\;Ty(t))$, and on the fundamental matrix of the unperturbed system y' = f(t, y) using the notion of h-stability.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제23권2호
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• pp.105-117
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• 2016

This paper shows that the solutions to the nonlinear perturbed differential system $y{\prime}=f(t,y)+\int_{t_0}^{t}g(s,y(s),T_1y(s))ds+h(t,y(t),T_2y(t))$, have the bounded property by imposing conditions on the perturbed part $\int_{t_0}^{t}g(s,y(s),T_1y(s))ds,h(t,y(t),T_2y(t))$, and on the fundamental matrix of the unperturbed system y′ = f(t, y) using the notion of h-stability.

• Journal of Pharmaceutical Investigation
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• 제33권3호
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• pp.245-253
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• 2003

Dissolution profile comparsions can be done by virtue of the similarity factor $(f_2)$. It is a logarithmic reciprocal square root transformation of the sum of squared error of % dissolution differences between two profiles at several time points. It gives information on the degree of similarity between the two profiles: An $f_2$ value between 50 and 100 suggests the similarity/equivalence of the two dissolution curves being compared. The objective of this report was to provide a careful examination on the $f_2$ metrics in detail. It was shown that $f_2$ values exceeded 50, when relative differences in % dissolved between two products were less than 15% at all time points. The similarity factor value was also found to be greater than 50, in cases when absolute % dissolution differences were below 10% at all time points. Interestingly, the $f_2$ value was changed by the number of the time points selected for calculation. In particular, $f_2$ tended to have higher values, when the $f_2$ metrics used a large number of time points in which % dissolved reached plateau. Finally, since the similarity factor was a sample statistics, it was impossible to infer type I/II errors and sampling error. Despite certain limitations inherited in the $f_2$ metrics, it was easy and convenient to evaluate how similar the two dissolution profiles were.

• 생태와환경
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• 제54권4호
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• pp.291-302
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• 2021

본 연구는 영산강 하구에 위치한 세 호수들에서 식물플랑크톤 군집의 분포 양상 및 호소 간 군집 유사성을 확인하고 군집 구조의 차이에 영향을 미치는 요인들을 확인하고자 2014년 3월부터 2017년 11월까지 분기별 조사를 시행하였다. 조사 결과, 식물플랑크톤의 종 다양성은 영산호에서 가장 높았고, 평균 개체수는 금호호에서 가장 높았으며, 영암호는 다른 호수들에 비해 식물플랑크톤의 종수와 개체수가 낮은 것으로 확인되었다. NMDS 분석 결과, 영산호와 금호호의 식물플랑크톤 군집 분포는 뚜렷한 차이를 나타냈고, 세 호수의 식물플랑크톤 군집 분포에 영향을 미치는 요인은 수온, DO, T-N, NO₃-N, 전기전도도 등으로 확인되었다. Random Forest 분석을 통해 각 호수의 식물플랑크톤 군집에 영향을 미치는 요인을 확인한 결과, 세 호수 모두 공통적으로 NO₃-N의 영향력이 높았다. Indicator species analysis를 통해 확인된 각 호소별 지표종은 총 24종으로, 영산호에서 13종으로 가장 많았고, 영암호에서 2종으로 가장 적었으며, 호소별 지표종의 분류군이 구별되었다. SIMPER 분석 및 ANOSIM 결과, 영산호와 영암호의 식물플랑크톤 군집은 유사성을 나타내었고, 금호호의 경우 다른 호수와의 식물플랑크톤 군집이 다소 차이가 있는 것으로 확인되었다. 또한 각 호수의 지점별 식물플랑크톤 군집 유사성은 지점에 따라 차이가 있어 식물플랑크톤 군집 형성에 대해 연락수로의 영향력은 낮은 것으로 조사되었다.

• 한국전산유체공학회지
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• 제6권1호
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• pp.21-30
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• 2001

A numerical study on the similarity of the developing laminar flows between in a straight duct rotating about an axis perpendicular to that of the duct and in a stationary curved duct was carried out. In order to clarify the analogy of two flows, dimensionless parameters K/sub LR/ = Re/(equation omitted) and Rossby number, Ro, in a rotating straight duct were used as a set corresponding to Dean number K/sub LC/ = Re/(equation omitted), and curvature ratio, λ, in a stationary curved duct. For the large values of Ro and λ, it is shown that the flow field satisfies the 'asymptotic invariance property', that is, there are strong quantitative similarities between the two flows such as flow patterns, friction factors, and maximum axial velocity magnitudes for the same values of K/sub LR/ and K/sub LC/ if they are correlated with dimensionless axial distances Z/sub R/ = z/(equation omitted) for a rotating duct flow and Z/sub C/ = z/(equation omitted) for a stationary curved duct flow.