• 충청수학회지
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• 제23권3호
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• pp.481-486
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• 2010

In this paper, we introduce the concepts of strongly c-convex( strongly c-concave) function, almost c-convex function on preconvex spaces. We investigate the relationships between such concepts and several types of preconvex sets.

• Journal of applied mathematics & informatics
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• 제29권1_2호
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• pp.517-521
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• 2011

In this paper, we introduce the concepts of m-convex set, mcconvex function and $m^*c$-convex function. We study basic properties for m-convex sets and characterization for such functions.

• 호남수학학술지
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• 제30권3호
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• pp.425-433
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• 2008

In this paper, we introduce the concept of p-preconvex sets on preconvexity spaces. We study some properties for p-preconvex sets by using the co-convexity hull and the convexity hull. Also we introduce and study the concepts of pc-convex function, $p^*c$-convex function, pI-convex function and $p^*I$-convex function.

• 대한수학회논문집
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• 제25권1호
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• pp.105-110
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• 2010

In this paper, we introduce the concept of $\beta$-preconvex sets on preconvexity spaces. We study some properties for $\beta$-preconvex sets by using the co-convexity hull and the convexity hull. Also we introduce and study the concepts of ${\beta}c$-convex function and $\beta^*c$-convex function.

• 대한수학회논문집
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• 제23권2호
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• pp.251-256
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• 2008

In this paper, we introduce the concept of the semi-preconvex set on preconvexity spaces. We study some properties for the semi-preconvex set. Also we introduce the concepts of the sc-convex function and $s^*c$-convex function. Finally, we characterize sc-convex functions, $s^*$-convex functions and semi-preconvex sets by using the co-convexity hull and the convexity hull.

• 호남수학학술지
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• 제29권4호
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• pp.589-595
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• 2007

In this paper, we introduce the concepts of the convexity hull and co-convex sets on preconvexity spaces. We study some properties for the co-convexity hull and characterize c-convex functions and c-concave functions by using the co-convexity hull and the convexity hull.

• 대한수학회논문집
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• 제37권2호
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• pp.537-549
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• 2022

In this paper, we consider a convex univalent function f_α,β which maps the open unit disc 𝕌 onto the vertical strip domain Ω_α,β = {w ∈ ℂ : α < ℜ < (w) < β} and introduce new subclasses of both close-to-convex and bi-close-to-convex functions with respect to an odd starlike function associated with Ω_α,β. Also, we investigate the Fekete-Szegö type coefficient bounds for functions belonging to these classes.

• 한국산업정보학회논문지
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• 제7권1호
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• pp.58-65
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• 2002

정수계획법모형에서 목적함수와 선형 제약조건식에 만족하는 최적해를 유도할 때, 선형 제약조건식으로 이루어지는 모든 가능해의 Convex set K에서 정수인 extreme point 또는 수정된 정수인 extreme point를 유도하여 목적함수Z의 최적해로 결정한다. 본 논문에서는 기저변수 벡터 $X_{B}$의 성분이 정수가 아닐 때 Branch & Bound 방법을 확장하여 $X_{B}$가 정수가 되도록 한다. 그리고 목적함수의 계수 $C_{j}$의 변동에 의하여 단계적으로 변하는 최적화를 유도함을 목적으로 한다. 한다.

• 대한수학회논문집
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• 제36권4호
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• pp.801-815
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• 2021

Ellipses have a lot of interesting geometric properties. It is quite natural to ask whether such properties of ellipses and some related ones characterize ellipses. In this paper, we study some chord properties and area properties of ellipses. As a result, using the curvature and the support function of a strictly convex curve, we establish four characterization theorems of ellipses and hyperbolas centered at the origin.

• 대한수학회보
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• 제45권1호
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• pp.39-44
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• 2008

In this paper, we introduce the concepts of pre convexity neighborhoods, c-concave functions. We study some properties for c-convex functions, and characterize c-convex functions and c-concave functions by using the preconvexity neighborhoods.