• School Mathematics
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• v.3 no.1
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• pp.45-74
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• 2001

In this paper, an analysis of survey questions relating to educational technology which was extracted from a more general survey of 1-12 mathematics teachers in Korea is reported. The general survey was conducted to provide a baseline for evaluating and developing recommendations for mathematics curriculum that is consistent with the knowledge based information society model of the future. The basic requirements for technology based education are availability of hardware and the ability of teachers to use technology for education. Therefore, the availability and use of technology by mathematics teachers in today’s curriculum was analyzed. The computer ability of teachers, the amount of computer use in the classroom, and the attitude of teachers about the use of technology for education was analyzed. The analysis is intended to provide a baseline of information for understanding and developing plans for better implementing technology for mathematic education.

• Journal of Korean Society for Quality Management
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• v.23 no.3
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• pp.126-139
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• 1995

We describe a formal approach to the construction of optimal classification rule for the two-group normal classification with equal population mean problem. Based on the utility function of Bernardo, we suggest a balanced design for the classification and construct the optimal rule under the balanced design condition. The rule is characterized by a constrained minimization of total risk of misclassification, the constraint of which is constructed by the process of equation between expected utilities of the two group conditional densities. The efficacy of the suggested rule is examined through numerical studies. This indicates that, in case little is known about the relative population sizes, dramatic gains in accuracy of classification result can be achieved.

• Journal of architectural history
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• v.6 no.3 s.13
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• pp.145-154
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• 1997

Le Corbusier had developed the Modulor replacing the Regulating Lines in the 1930's and 1940's. The lines can not produce lyrical ideas or creational concept but make plastic dimension pure only to keep in balance. First, the Grid of Proportions was developed and then the Modulor 1. The Modulor originated in one square, double square, the two golden means added or subtracted, the place of the right angle, human dimension, the Fibonacci series and divided Red series and Blue series. He developed the Modulor 2 for a reconciliation between the foot-and-inch system and the metre. As Corbusier devoted himself to a social and industrial problem, he was sure that a transcendental universality be in cosmos including a human being. His dream was to creat a orderly and harmonious utopia. What intrinsic harmony between Cosmos, nature and a human being be realized by mathematic order was the reason he hinted himself to the proportion.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.1
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• pp.14-22
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• 1998

The Mathematic model of bit synchronization charge-pump Phase Locked Loop (PLL) is presented which takes into account the aperiodic reference pulses and the leakage current of the loop filter. We derive theoreitcal static phase error, overload and stability of bit synchronization charge-pump PLL using presented model and compare it with one of the conventional charge-pump PLL model. We can analysis bit synchronization charge-pump PLL exactly because our model takes into account the leakage current of the loop filter and aperiodic input data which are the charateristics of bit synchronization charge-pump PLL. We also verify it using HSPICE simulation with a bity synchronizer circuit.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.07a
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• pp.21-25
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• 2003

Key exposure is the most devastating attacks in any crytographic scheme. In this paper, we investigate key exposure problem in blind signature. We then present a variant of Okamoto-Guillou-Quisquater (OGQ for short) blind signature scheme guaranteeing forward secrecy. Namely, even if current secret key is revealed, forging any signature valid in the past is impossible. Our proposed scheme exhibits an efficient key updating protocol and introduces no significant communication overhead.

• Journal of applied mathematics & informatics
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• v.30 no.5_6
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• pp.951-969
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• 2012

In this paper, we propose a class of meshless collocation approaches for the solution of time dependent partial differential algebraic equations (PDAEs) in terms of a radial basis function interpolation numerical scheme. Kansa's method and the Hermite collocation method (HCM) for PDAEs are given. A sensitivity analysis of the solutions from different shape parameter c is obtained by numerical experiments. With use of the random collocation points, we have obtain the more accurate solution by the methods than those by the finite difference method for the PDAEs with index-2, i.e, we avoid the influence from an index jump of PDAEs in some degree. Several numerical experiments show that the methods are efficient.

• Communications of the Korean Mathematical Society
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• v.17 no.3
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• pp.487-493
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• 2002

Given operators X and Y acting on a Hilbert space H, an interpolating operator is a bounded operator A such that AX = Y. An interpolating operator for the n-operators satisfies the equation AX$\_$i/ : Y$\_$i/, for i = 1, 2 …, n. In this article, we obtained the following : Let X = (x$\_$ij/) and Y = (y$\_$ij/) be operators acting on H such that $\varkappa$$\_$ i$\sigma$ (i)/ 0 for all i. Then the following statements are equivalent. (1) There exists a unitary operator A in Alg(equation omitted) such that AX = Y and every E in (equation omitted) reduces A. (2) sup{(equation omitted)}<$\infty$ and (equation omitted) = 1 for all i = 1, 2, ….

• Journal of the Korean Mathematical Society
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• v.41 no.6
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• pp.977-994
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• 2004

A pair of quasi-definite linear functionals {u$_{0}$, u$_1$} is a generalized $\Delta$-coherent pair if monic orthogonal polynomials (equation omitted) relative to u$_{0}$ and u$_1$, respectively, satisfy a relation (equation omitted) where $\sigma$$_{n}$ and T$_{n}$ are arbitrary constants and $\Delta$p = p($\chi$＋1) - p($\chi$) is the difference operator. We show that if {u$_{0}$, u$_1$} is a generalized $\Delta$-coherent pair, then u$_{0}$ and u$_{1}$ must be discrete-semiclassical linear functionals. We also find conditions under which either u$_{0}$ or u$_1$ is discrete-classical.ete-classical.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.563-566
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• 2002

This paper presents the modeling and analysis of wind turbine generating system(WTGS) using doubly fed induction machine as a generator Generally, wind turbine generating system is composed of complicated machinery. So it is very difficult to present the mathematic model. This means that WTGS has a nonlinear system. Using the real output data from the WTGS for one year, it is simply possible to express the rotor and gear coupling system as a torque generator according to wind speed. Also, the modeling of electrical system can be able to present using the data sheet from the company. To analyze the proposed method, computer simulation using Psim program are presented to support the discussion.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.1
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• pp.34-40
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• 2007

Balasubramaniam and Muralisankar (2004) proved the existence and uniqueness of fuzzy solutions for the semilinear fuzzy integrodifferential equations with nonlocal initial condition. Park et al. (2006) found the sufficient condition of this system. Recently, Kwun et al. (2006) proved the existence and uniqueness of solutions for the semilinear fuzzy integrodifferential equations with nonlocal initial conditions and forcing term with memory in $E_N$. In this paper, we study the controllability for this system by using the concept of fuzzy number whose values are normal, convex, upper semicontinuous and compactly supported interval in $E_N$.