• Review of KIISC
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• v.3 no.1
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• pp.86-90
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• 1993

Finite field GF$(2^n)5에서 정의된 elliptic curve가 있을때 그 curve위의 어떤 point p를 k배하는 연산은 암호론에서 매우 자주 쓰여진다. 이때 optimal normal bases를 이용하여 GF$(2^n)의 element를 표현하고, 또 elliptic curve를 선택할 때 animalous curve가 되도록 한다면, 기존이 방법 보다 매우 빠르게 k P를 구할 수 있다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.429-430
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• 2006

To estimate the fatigue life of flange-shaft assembly, fatigue test for flange material and bending fatigue test for flange-shaft assembly were conducted. Also, finite element analysis for flange-shaft assembly was conducted. Then, we have changed the obtained P-N curve to S-N curve using the finite element analysis results which were stress values at the location of fracture. The S-N curve of flange material itself was almost consistent with that of flange-shaft assembly, so it seems that the fatigue life of flange-shaft assembly could be estimated by using S-N curve for flange material and the stress at the location of fracture calculated by finite element methods.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.217-222
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• 2001

For the life evaluating of notched members, it is the best way that performing the real fatigue test of structure containing notch. But this method required generally much times and costs to evaluate fatigue life. So, generally we use the modified S-N curve or several methods to predict fatigue life. In this study, crack initiation life was evaluated by fatigue testing the SAE keyhole specimen and smooth specimen made of Al 7075-T6 alloys using the constant load then obtained S-N curve of smooth specimen and P-N curve of SAE keyhole specimen. And, fatigue lives of keyhole specimen are predicted using some life prediction methods (Nominal range I method, Nominal range II method, FEM analysis) for investigating experimented results, and that were compared with experimental data. Predicted fatigue lives by FEM analysis were corresponded with experimental data between 1/3times and 3times on the whole, and predicted fatigue lives using modified S-N curve (Nominal range I method, Nominal range II method) were nonconservative compared with that of FEM analysis.

• Honam Mathematical Journal
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• v.33 no.2
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• pp.153-161
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• 2011

Greg([Greg]) considered that $$N_k= \sum\limits_{i=1}^k(-1)^{i+1}P_{i,k}(p)N_1^i$$ where the $P_{i,k}$'s were polynomials with positive integer coefficients. In this paper, we will give the equations for $\sum\limits{P_{i,k}$ modulo 3. Using this, if we send a information for elliptic curve to sender, we can make a new checksum method for Manchester coding in IEEE 802.3 or IEEE 802.4.

• Journal of Environmental Impact Assessment
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• v.22 no.4
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• pp.319-327
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• 2013

This study was conducted to identify runoff characteristics of pollutants using flow duration curve(FDC) and load duration curve(LDC) in Youngbon A watershed during 2009~2011. A flow rate and pollutant load in the study watershed were estimated by equation of stage-discharge and discharge-loads rating curve. From these methods, BOD, T-N, and T-P have evaluated whether water quality standards would have attained. Results showed that BOD loads of about 50% plotted above the LDC, while T-N and T-P loads of about 50% plotted below the curve. It means that BOD of about 50% have exceeded the water quality criteria, while T-N and T-P of about 50% have complied with the water quality standards. Meanwhile, BOD, TN and T-P loads plotted above the LDC of low flows, implying that they were more affected by point pollution sources than nonpoint pollution sources in the study watershed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1207-1212
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• 2015

A vibro ripper utilizes high-frequency vibration for rock fragmentation. This concept is different from those used by other existing breakers. The gearbox-shank welded joint of a vibro ripper is a very important part. Because it delivers the vibromotive force to the tooth, it is important to predict its soundness. This study was conducted to predict the fatigue life under welding conditions. The shank materials were Hardox-Hituf and AR400, and the filler metals were CSF-71T and CSF-81T. Fatigue tests were conducted under each set of conditions. P-S-N curves are presented based on the statistical testing method recommended by JSME-S002, and a comparison is made of the results under each set of conditions. The life was estimated using a P-S-N curve.

• Journal of Internet of Things and Convergence
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• v.6 no.2
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• pp.25-29
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• 2020

The elliptic curve crypto-algorithm is widely used in authentication for IoT environment, since it has small key size and low communication overhead compare to the RSA public key algorithm. If the scalar multiplication, a core operation of the elliptic curve crypto-algorithm, is not implemented securely, attackers can find the secret key to use simple power analysis or differential power analysis. In this paper, an elliptic curve scalar multiplication algorithm using a randomized scalar and an elliptic curve point blinding is suggested. It is resistant to power analysis but does not significantly reduce efficiency. Given a random r and an elliptic curve random point R, the elliptic scalar multiplication kP = u(P+R)-vR is calculated by using the regular variant Shamir's double ladder algorithm, where l+20-bit u≡rn+k(modn) and v≡rn-k(modn) using 2^lP=∓cP for the case of the order n=2^l±c.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.410-411
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• 2007

To investigate the ZnO LED which are interested in the next generation of short wavelength LEDs and Lasers, the ZnO thin films were deposited by RF magnetron sputtering system. The p-type ZnO thin film, fabricated by means of the ampoule-tube method, was used to make the ZnO p-n junction, and its characteristics was analyzed. The ampoule-tube method was used to make the p-type ZnO based on the As diffusion, and the hall measurement was used to confirm that the p-type is formed. the current-voltage characteristics of the ZnO p-n junction were measured to confirm the rectification characteristics of a typical p-n junction and the low leakage voltage characteristics. Analysis of ZnO LED V-I curve will provide a very useful technology for producing the UV ZnO LED and ZnO-based devices.

• The Pure and Applied Mathematics
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• v.23 no.3
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• pp.309-317
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• 2016

As a generalization of an inflection point, we consider a point P on a smooth plane curve C of degree m at which another curve C' of degree n meets C with high intersection multiplicity. Especially, we deal with the existence of two curves of degree m and n meeting at the unique point.

• Journal of the Korean Mathematical Society
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• v.33 no.2
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• pp.367-379
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• 1996

Let $V = {(z, y) : f(z, y) = z^n + Ay^\alpha z^p + y^\beta z^q + y^k = 0}$ and $W = {(z, y) : g(z, y) = z^n + By^\gamma z^s + y^\delta z^t + y^k = 0}$ be germs of analytic irreducible subvarieties of a polydisc near the origin in $C^2$ with n < k and (n, k) = 1 where A and B are complex numbers. Assume that V and W are topologically equivalent near the origin.