• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1601-1606
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• 1991

We present an algorithm to approximate the Voronoi diagrams of 2D objects bounded by algebraic curves. Since the bisector curve for two algebraic curves of degree d can have a very high algebraic degree of 2 * d$^{4}$, it is very difficult to compute the exact algebraic curve equation of Voronoi edge. Thus, we suggest a simple polygonal approximation method. We first approximate each object by a simple polygon and compute a simplified polygonal Voronoi diagram for the approximating polygons. Finally, we approximate each monotone polygonal chain of Voronoi edges with Bezier cubic curve segments using least-square curve fitting.

• Journal of the Korean Statistical Society
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• v.30 no.1
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• pp.99-113
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• 2001

This paper deals with the problem of estimating the means in two inverse Gaussian populations with equal but unknown coefficient of variation. The maximum likelihood estimators are derived by solving a cubic equation and their asymptotic variances are presented for comparative purpose. Monte-Carlo simulation is conducted to investigate the efficiency of the estimators relative to the sample means over a wide range of values for the sample size and the coefficient of variation. The effect on this efficiency under the departure from the assumption of common coefficient of variation is also studied.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.143-147
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• 1998

In this study, nonlinear stiffness characteristics of a discharge valve in a small hermetic compressor was considered. It was approximated, with piecewise-linearity, and cubic or quintic nonlinearity by the static load-displacement experimental results. Based on the fluid-structure interaction effects and mass flow rate, the derived 1-DOF equation of motion for the valve model was analyzed. Finally, the dynamic response of the discharge valve was studied with parameters such as the ratio of the running frequency of the compressor to the linear natural frequency of the valve.

• Journal of the Korean Mathematical Society
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• v.39 no.6
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• pp.821-879
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• 2002

Let U, V and W be complex vector spaces of dimensions 3, 3 and 4 respectively. The reductive algebraic group G = PGL(U) $\times$ PGL(W) $\times$ PGL(W) acts linearly on the projective tensor product space (equation omitted). In this paper, we show that the G-equivalence classes of the projective tensors are in one-to-one correspondence with the PGL(3)-equivalence classes of unordered configurations of six points on the projective plane.

• Kyungpook Mathematical Journal
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• v.55 no.2
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• pp.313-326
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• 2015

In this paper, we present a fixed point method to prove generalized Hyers-Ulam stability of the systems of quadratic-cubic functional equations with constant coefficients in modular spaces.

• Journal of Educational Research in Mathematics
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• v.9 no.1
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• pp.239-244
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• 1999

This study aims to present the necessity of 'mathematics for teacher' and advices for enhancing professionalism of mathematics teacher. Many mathematics teachers don't know formula giving roots of cubic and quartic equation which is presented as a example of mathematics for teacher, but they feel the necessity of professional knowledge like mathematics for teacher. As the role of mathematics teachers changes, professionalism in various fields is required. That is, they must be equipped with the belief and attitude as a professional and understand the content of mathematics for teacher and mathematics education theory. After all, loaming mathematics depends on the quality of mathematics teacher.

• Industrial Engineering and Management Systems
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• v.7 no.1
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• pp.1-8
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• 2008

Having previously presented an article entitled "Further approximate optimum inspection intervals" in this Journal, here the author derives an alternative set of general explicit formulae using Cardan's solution to a cubic equation and presents a modified heuristic algorithm for solving Baker's model. The examples show that this new alternative approximate solution procedure for determining near optimum inspection intervals is as accurate and computationally efficient as the one suggested in the previous article. Through the examples, the author also indicates the relative merits and demerits of the two algorithms.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.27-38
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• 1996

A two-dimensional FEM program, which considers bending effects in the membrane fromulation, was developed under plane strain assumption for analyzing forming processes of an arbitrarily shaped draw-die of automotive panels. For the evaluation of bending effects with membrane elements, the bending equivalent forces and stiffnesses are calculated from the bending moment computed using the changes in curvature of the formed shape of two membrane ones. The curves depicted with 3 nodes are described by a circle, a quadratic equation, and a cubic equation, respectively, and in the simulation of the stretch/draw sections of an automotive inner panel, three different description results are compared each other. Also, the bending results are compared with membrane results and measurements in order to verify the validity of the developed program.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.547-550
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• 2005

In many machines handling lightweight and flexible media, such as automated teller machines and printers, the media must transit an open space. It is important to predict the static and dynamic behavior of the sheets with a high degree of reliability The nonlinear theory of the dynamic elastica has often been used to a nonlinear dynamic deflection model. In this paper, the governing equation is derived and simulated by the finite difference method. The analysis has to include aerodynamic effect for more exact behavior analysis, because the flexible media can be deformed drastically by a little force. Therefore aerodynamic force must be applied to the governing equation. Different results were obtained with and without aerodynamic effect and the resulted show that after contacting circular guide, the directions of flexible media of two cases are different.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.3
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• pp.156-160
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• 1992

The evolution of leading waves generated by a wavemaker in a two-dimensional tank has been studied. The front of wave trains can be described in general by the Schrodinger equation. In particular, when the slope of the carrier waves is steep, and hence nonlinearity becomes important, the cubic Schrodinger equation is proved to be an appropriate mathematical model. Computations are made by using the Crank-Nicolson algorithm and compared with experimental data. It is found that the numerical result predicts the evolution of leading waves fairly well and the evolution is significantly affected by nonlinearity for steep waves when kh＞1.36.