• Bulletin of the Korean Mathematical Society
• /
• v.42 no.1
• /
• pp.39-44
• /
• 2005

Let M be a compact hypersurface in hyperbolic space and let A be the area of M and V be the volume of the compact domain bounded by M. In this paper, we find a lower bound for $\frac{A}{V}$ in two cases, M has constant scalar curvature and M has constant mean curvature.

• Communications of the Korean Mathematical Society
• /
• v.30 no.2
• /
• pp.131-142
• /
• 2015

The purpose of this paper is to study real hypersurfaces immersed in a complex hyperbolic space $CH^n$ and especially to investigate certain curvature conditions for such real hypersurfaces to be the model hypersurfaces in classification theorem (said to be Theorem M-R) given by Montiel and Romero ([4]) in Section 3.

• Journal of the Korean Mathematical Society
• /
• v.48 no.1
• /
• pp.133-146
• /
• 2011

We employ a hyperbolic tangent function to construct nonlinear transformations which are useful in numerical evaluation of weakly singular integrals and Cauchy principal value integrals. Results of numerical implementation based on the standard Gauss quadrature rule show that the present transformations are available for the singular integrals and, in some cases, give much better approximations compared with those of existing non-linear transformation methods.

• Journal of the Korean Mathematical Society
• /
• v.46 no.6
• /
• pp.1267-1276
• /
• 2009

This paper presents a method for approximation of the standard normal distribution by using hyperbolic tangent based functions. The presented approximate formula for the cumulative distribution depends on one numerical coefficient only, and its accuracy is admissible. Furthermore, in some particular cases, closed forms of inverse formulas are derived. Numerical results of the present method are compared with those of an existing method.

• Proceedings of the IEEK Conference
• /
• 1999.11a
• /
• pp.767-770
• /
• 1999

This paper investigates the performance of the hyperbolic position location(PL) technique in CDMA system. Hyperbolic PL systems are such technology that can provide accurate PL information using the existing cellualr/PCS infrastructure and without requiring additional hardware/software implementation within the mobile unit. The channel simulation is obtained by applying AWGN and multipath fading. The effect of the mobile position within the cell and the number of base stations on the accuracy of the hyperbolic PL technique is investigated.

• Journal of applied mathematics & informatics
• /
• v.5 no.1
• /
• pp.23-40
• /
• 1998

Mixed finite element method is developed to approxi-mate the solution of the initial-boundary value problem for a strongly nonlinear second-order hyperbolic equation in divergence form. Exis-tence and uniqueness of the approximation are proved and optimal-order $L\infty$-in-time $L^2$-in-space a priori error estimates are derived for both the scalar and vector functions approximated by the method.

• Journal of the Korean Mathematical Society
• /
• v.37 no.2
• /
• pp.297-308
• /
• 2000

We survey results, obtained in the past three years, on characterizing bounded (and Kobayashi-hyperbolic) Reinhardt domains by their automorphism groups. Specifically, we consider the following two situations: (i) the group is non-compact, and (ii) the dimension of the group is sufficiently large. In addition, we prove two theorems on characterizing general hyperbolic complex manifolds by the dimensions of their automorphism groups.

• Communications of the Korean Mathematical Society
• /
• v.32 no.4
• /
• pp.1009-1024
• /
• 2017

In this paper, we consider the new faster iterative scheme due to Sintunavarat and Pitea ([32]) for further investigation and we prove its strong and ${\Delta}$-convergence theorems, data dependence and stability results in hyperbolic space. Our results extend, improve and generalize several recent results in CAT(0) space and uniformly convex Banach space.

• Proceedings of the Korean Information Science Society Conference
• /
• 2001.10b
• /
• pp.217-219
• /
• 2001

복잡한 제어가 필요한 설비의 운전 정보나 네트워크 연결 상태 또는 웹 문서간의 정보 등을 제한된 컴퓨터 화면에 효과적으로 배치하는 시각화 기법에 관한 논의가 활발히 진행되고 있다. 이 경우 한눈에 전체 정보의 계층 구조를 파악하도록 하는 환경을 제공하며, 사용자가 관심 있는 정보에 대해서는 전체 정보 계층 구조를 유지하면서 보다 상세히 그 내용을 보여주는 그래픽 기반의 사용자 인터페이스 판결의 개발이 필요하다. 이에 쌍곡선 기하학(Hyperbolic Geometry)을 기반으로 한 시각화기법으로 새로운 제어 환경을 구현하여 사용자의 편의를 도모하도록 한다.

• East Asian mathematical journal
• /
• v.15 no.2
• /
• pp.325-336
• /
• 1999

In this paper, we prove that any $\lambda$-firmly nonexpansive mapping ($0<\lambda<1)T:C{\rightarrow}C$ has a fixed point in C whenever C is a finite union of nonempty, bounded, closed and convex subsets of a metric space of hyperbolic type.