• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.94-100
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• 2004

A dynamic finite element analysis of a rig test model for truck chassis systems is conducted to establish an appropriate model designed to predict the fatigue life. A reference Belgian road input, which has been obtained from a field test, is imposed on the finite element model in the modal finite element analysis, and the resulting strain history is employed for the prediction of the fatigue life. This is compared with the prediction based upon the strain history measured in the field test. The two agree with each other within the limitation of the field data and the input data to the model. The high frequency responses over 50 Hz are confirmed to be negligible as far as their effect on the fatigue life is concerned.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.718-722
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• 2014

A method for estimating the cylindrical shape of a sound radiator is presented. It assumes that sound field can be measured by a linear array. A sound field, due to the radiator vibrating with uniform velocity, can be determined by its shape, size, and orientations. Measured data also can be varying from the array's position. To predict the shape of radiators from these measured data, mathematical relation between geometric parameter and measured information is needed. Assume that a radiator is cylinder, the magnitude and phase of measured pressure is related with the length and diameter of radiator, respectively. In this paper, the method for estimating length and shape of a finite cylinder by using its radiated pressure is proposed and verified through experiment.

• Review of KIISC
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• v.9 no.3
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• pp.97-104
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• 1999

전산 정수론의 몇 몇 이론들과 그 계산 방법들은 최근 컴퓨터 및 네트웍의 발달로 그 유용성을 한층 증대 시키고 있다. 본 연구는 이들 전산 정수론의 방법들중에서 정수들의 집합 위에서의 다항식 계산의 복잡도를 이용하여 암호화 프로토콜에 응용하는 연구를 수행 하여 그것을 암호학의 제 분야에서 활발히 활용되는 해쉬 알고리즘을 구성하였다. 또한 이 러한해쉬 알고리즘을 이용하여 암호화 프로토콜의 하나인 인증프로토콜을 연구하였다. 먼저 group SL2(F2n)에 기초한 해쉬 함수에 대해 알아본다. 행력의 각 entry는 characteristic이 인 finite field의 원소로 이루어져 있기 때문에 연산 속도도 매우 빠르며 메시지의 작은 변 조도 쉽게 감지할수 있다는 장점이 있다. 하지만 SL2(F2n)에 generator를 finite field의 원 로표현하고 finite field F2n 상에서 discrete logarithm을 계산하면 충돌하는 메시지쌍이 존 하는 것을 알수는 있으나 이는 계산적으로 계산불가능함을 증명하였다.

• Geomechanics and Engineering
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• v.8 no.2
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• pp.133-152
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• 2015

Mathematical model has been developed for determination of temperature field in multilayer pavement and subgrade, which considers transfer of heat by conduction and convection, receiving of heat from total solar radiation and atmosphere emission, output of heat due to the emission from the surface of pavement. The developed model has been realized by the finite element method for two dimensional problem using two dimensional second order finite element. Calculations for temperature field have been made with the programme realized on the standard mathematical package MATLAB. Accuracy of the developed model has been evaluated by comparison of temperatures, obtained theoretically and experimentally. The results of comparison showed high accuracy of the model. Long-term calculation (within three months) has been made in pavement points in accordance with the data of meteorological station for air temperature. Some regularities have been determined for variation of temperature field.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.10
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• pp.799-806
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• 1991

Utilizing dual basis, normal basis, and subfield representation, three different finite field multipliers are presented in this paper. First, we propose an extended dual basis multiplier based on Berlekamp's bit-serial multiplication algorithm. Second, a detailed explanation and design of the Massey-Omura multiplier based on a normal basis representation is described. Third, the multiplication algorithm over GF(($2^{n}$) utilizing subfield is proposed. Especially, three different multipliers are designed over the finite field GF(($2^{4}$) and the complexity of each multiplier is compared with that of others. As a result of comparison, we recognize that the extendd dual basis multiplier requires the smallest number of gates, whereas the subfield multiplier, due to its regularity, simplicity, and modularlity, is easier to implement than the others with respect to higher($m{\ge}8$) order and m/2 subfield order.

• Journal of the Chungcheong Mathematical Society
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• v.28 no.3
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• pp.443-449
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• 2015

In this paper we propose a method of computing the number of points on the reduction of non-hyperelliptic modular curves of genus greater than or equal to 3 over finite fields.

• Bulletin of the Korean Mathematical Society
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• v.20 no.2
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• pp.81-85
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• 1983

It is the purpose of this paper to give some remarks on finite fields. We shall show that the little theorem of Fermat, Euler's criterion for quadratic residue mod p, and other few theorems in the number theory can be derived from the theorems in theory of finite field K=GF(p), where p is a prime. The forms of some irreducible ploynomials over K-GF(p) will be given explicitly.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.8
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• pp.1137-1144
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• 1989

In this paper, for eliminating the spurious solutions which have been necessarily included in the solutions of earlier vectorial finite-element method, we have proposed the improved finite-element method for the analysis of dielectric waveguides in the three-component magnetic field.

• Journal of the Chungcheong Mathematical Society
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• v.22 no.3
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• pp.299-307
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• 2009

We count the isomorphism classes of elliptic curves over finite fields $\mathbb{F}_{3^{n}}$ and list a representative of each isomorphism class. Also we give the number of rational points for each supersingular elliptic curve over $\mathbb{F}_{3^{n}}$.

• Journal of KSNVE
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• v.3 no.2
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• pp.169-178
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• 1993

Internal & External duct acoustic fields are calculated by using a finite element method. The geometry is assumed as an axisymmetric duct. External acoustic field; outside the duct, and combined internal & external acoustic fields are solved. For both cases a far field's nonreflecting boundary condition is enforced by using a wave envelope element, which is a kind of finite element. First, a pulsating sphere and an oscillating sphere problem are calculated to verify the external problems, and the results are compared with exact solutions. When the wave envelope element is applied at the far boundary, the calculated finite element solutions show good agreements with the exact solutions. Secondly, the combined internal & external duct acoustic fields are calculated and visualized when monopole sources are distributed inside the duct. It is observed that the directivity of sound intensity outside the duct is beaming toward the axis for high frequency sources.