• Journal of KIISE:Computing Practices and Letters
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• v.15 no.4
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• pp.270-274
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• 2009

In this paper, we propose an efficient computation method over GF($2^m$) for memory-constrained devices. While previous methods concentrated only on fast multiplication, we propose to reduce the amount of required memory by cleverly changing the order of suboperations. According to our experiments, the new method reduces the memory consumption by about 20% compared to the previous methods, and it achieves a comparable speed with them.

• Publications of The Korean Astronomical Society
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• v.22 no.4
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• pp.141-149
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• 2007

Preliminary time-series observations for short-period variability survey (SPVS) were carried out using a 155mm refractor and a $2k{\times}3k$ CCD camera at Bohyunsan Optical Astronomy Observatory. We found 21 new variable stars in the $90'{\times}60'$ test field region : 9 eclipsing binary stars, $5{\delta}$ Scuti type stars, a ${\gamma}$ Doradus type star, and 6 long period variables. The observing field center is R.A. $05^h\;00^m\;00^s$, DEC. $50^{\circ}\;00'\;00"$ (J2000.0). The period and amplitude ranges for the short-period variables, i.e., ${\delta}$ Scuti stars, were 0.052day - 0.107day and 0.012mag - 0.064mag, respectively.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1195-1200
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• 2004

A fully coupled fluid flow, heat, and solute transport model was developed to investigate turbulent flow, solidification, and macrosegregation in a continuous casting process of steel slab with EMBR. Transport equations of mass, momentum, energy, and species for a binary iron-carbon alloy system were solved using a continuum model. The electromagnetic field was described by the Maxwell equations. A finite-volume method was employed to solve the conservation equations associated with appropriate boundary conditions. The effects of intensity of magnetic field and carbon segregation were investigated. The electromagnetic field reduces the velocity of molten flow in the mold and an increase in the percentage of C in steel results in a decrease of carbon segregation ratio.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.242-245
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• 2002

본 논문은 ARM7TDMI 프로세서를 사용하여 유한체 GF(2$^{m}$ ) 상에 정의된 타원곡선 암호시스템을 구현한 결과를 제시한다. 타원곡선의 점을 표현하는 좌표계에 따른 비교를 하였고, 사전 계산과 사전 계산을 하지 않는 알고리즘의 구현 결과를 비교하고 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.64-66
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• 2005

본 논문에서는 GF($2^m$) 상에서 나눗셈 연산을 위한 고속 알고리듬을 제안하고, 제안한 알고리듬을 기본으로 한 나눗셈 연산기의 하드웨어 설계 및 구현에 관하여 기술한다. 나눗셈을 위한 모듈러 연산은 개선된 이진 확장 유클리드 알고리듬 (Binary Extended Euclidian algorithm) 을 기본으로 하고 있다 성능비교 결과로부터 제안한 방법은 기존 방법에 비해 지연시간이 약 $26.7\%$ 정도 개선됨을 확인하였다.

• The Journal of Society for e-Business Studies
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• v.8 no.1
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• pp.113-119
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• 2003

This paper proposes a new multiplicative inverse algorithm for the Galois field GF (2/sup m/) whose elements are represented by optimal normal basis type Ⅱ. One advantage of the normal basis is that the squaring of an element is computed by a cyclic shift of the binary representation. A normal basis element is always possible to rewrite canonical basis form. The proposed algorithm combines normal basis and canonical basis. The new algorithm is more suitable for implementation than conventional algorithm.

• Journal of Astronomy and Space Sciences
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• v.10 no.2
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• pp.113-122
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• 1993

Using a simple analytic model based on the MHD stability arguments we obtain the size of the magnetosphere for the magnetic compact stars. We assume the ordered, field-aligned flow in the magnetosphere and estimate the wellknown Alfven radius. The dependence of the X-ray absorption in the magnetic funnel on the size of this radius is further considered. We show that such a determination of the magnetic interaction radius can be applied to the reconstruction of X-ray light curves of the magnetic binary stars.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.29.1-29.1
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• 2016

I introduce the field of gravitational microlensing that I have worked on for more than 2 decades. I describe how microlensing can be applied to various fields in astrophysics including dark matter, Galactic structure, binary objects, and extrasolar planets and present my scientific achievements in the individual fields. I start with a description of basic microlensing physics and state how microlensing can be applied to various fields. Finally, I briefly describe ongoing efforts and future projects in microlensing.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.719-726
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• 2016

The problem of separation of isotopes in a concurrent gas centrifuge is solved analytically for an arbitrary binary mixture of isotopes. The separative power of the optimised concurrent gas centrifuges for the uranium isotopes equals to ${\delta}U=12.7(V/700m/s)^2(300K/T)(L/1m)kg{\cdot}SWU/yr$, where L and V are the length and linear velocity of the rotor of the gas centrifuge and T is the temperature. This equation agrees well with the empirically determined separative power of optimised counter-current gas centrifuges.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.273-273
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• 2000

We present a new scheme to increase the performance of edge-preserving image smoothing from the parameter tuning of a Markov random field (MRF) function. The method is based on automatic control of the image smoothing-strength in MRF model ing in which an introduced parameter function is based on control of enforcing power of a discontinuity-adaptive Markov function and edge magnitude resulted from discontinuities of image intensity. Without any binary decision for the edge magnitude, adaptive control of the enforcing power with the full edge magnitude could improve the performance of discontinuity-preserving image smoothing.