• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.5
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• pp.295-305
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• 2023

This study introduces a smoothed finite-element implementation into the phase-field framework. In recent years, the phase-field method has recieved considerable attention in crack initiation and propagation since the method needs no further treatment to express the crack growth path. In the phase-field method, high strain-energy accuracy is needed to capture the complex crack growth path; thus, it is obtained in the framework of the smoothed finite-element method. The salient feature of the smoothed finite-element method is that the finite element cells are divided into sub-cells and each sub-cell is rebuilt as a smoothing domain where smoothed strain energy is calculated. An adaptive quadtree refinement is also employed in the present framework to avoid the computational burden. Numerical experiments are performed to investigate the performance of the proposed approach, compared with that of the finite-element method and the reference solutions.

• Journal of IKEEE
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• v.7 no.1 s.12
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• pp.9-15
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• 2003

An optimized finite-field multiplier is proposed for encryption and error correction devices. It is based on a modified Linear Feedback Shift Register (LFSR) which has lower power consumption and smaller area than prior LFSR-based finite-field multipliers. The proposed finite field multiplier for GF(2n) multiplies two n-bit polynomials using polynomial basis to produce $z(x)=a(x)^*b(x)$ mod p(x), where p(x) is a irreducible polynomial for the Galois Field. The LFSR based on a serial multiplication structure has less complex circuits than array structures and hybrid structures. It is efficient to use the LFSR structure for systems with limited area and power consumption. The prior finite-field multipliers need 3${\cdot}$m flip-flops for multiplication of m-bit polynomials. Consequently, they need 6${\cdot}$m latches because one flip-flop consists of two latches. The proposed finite-field multiplier requires only 4${\cdot}$m latches for m-bit multiplication, which results in 1/3 smaller area than the prior finite-field multipliers. As a result, it can be used effectively in encryption and error correction devices with low-power consumption and small area.

• Journal of Industrial Technology
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• v.18
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• pp.131-138
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• 1998

Numerical modeling for electromagnetic exploration methods are essential to understand behaviours of electromagnetic fields in complex subsurfaces. In this study, a finite element method was adopted as a numerical scheme for the 2.5-dimensional forward problem. And a finite element equation considering linear conductivity variation was proposed when 2.5-dimensional differential equation to couple eletric and magnetic field was implemented. Model parameters were investigated for near-field with large source effects and far-field with responses dominantly by homogeneous half-space. Numerical responses by this study were compared with analytic solutions in homogeneous half-space and compared with other three dimensional numerical results.

• East Asian mathematical journal
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• v.33 no.1
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• pp.45-52
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• 2017

Motivated by the problem of determining all right ideals of a group algebra FG for a finite group G over a finite field F, we explicitly determine the faithful irreducible representations of some finite metacylic groups over finite fields. By using that result, we determine the structure of all right ideals of the group algebra for the symmetric group $S_3$ over a finite field F, as an example.

• Bulletin of the Korean Mathematical Society
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• v.55 no.6
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• pp.1811-1822
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• 2018

In this paper, we exhibit the explicit forms of continued fraction expansions of a family of algebraic power series over a finite field and we study their asymptotic distribution of approximation exponents.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.8
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• pp.1207-1212
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• 2013

Arithmetic operations over finite fields are widely used in coding theory and cryptography. In both of these applications, there is a need to design low complexity finite field arithmetic units. The complexity of such a unit largely depends on how the field elements are represented. Among them, representation of elements using a optimal normal basis is quite attractive. Using an algorithm minimizing the number of 1's of multiplication matrix, in this paper, we propose a multiplier which is time and area efficient over finite fields with optimal normal basis.

• The Journal of the Acoustical Society of Korea
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• v.38 no.5
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• pp.511-521
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• 2019

In this study, we theoretically study the acoustic scattering of an obliquely incident plane wave from a finite elastic cylindrical shell. A heuristic scattering method of Ye [Z. Ye, J. Acoust. Soc. Am. 102, 877-884 (1997)] for a finite fluid cylinder is extended into a finite elastic cylindrical shell since no analytic solutions exist in the finite cylinder. The elastic cylindrical shell is modeled with the 3D elastic wave theory considering internal fluid. Using the derived analytic solution, we observe the effect of the internal fluid on the scattering field, the scattering field for the Rayleigh parameter, and the far-field scattering function for the elastic property of the cylindrical shell.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.1
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• pp.24-30
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• 1991

This paper deals with the analysis of the transient characteristics of a superconducting a.c. generator(SCG) using Finite Element Method. Since the magnetic field induced by the field current and the armature currents are not sinusoidally distributed in a generator, the conventional equivalent circuit method, in general, uses the fundamental component only and is done in frequency domain. But the finite element analysis makes it possible to analyze the transient magnetic field distribution and the electrical characteristics of the double shields of SCG in time domain.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.49-52
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• 1989

Some limits are in two-dimensional analysis by finite element method to electromagnetic machine having finite dimension. Therefore three-dimensional analysis by finite element method, which are modeling original form of models are needed in order to gain accurate solutions. This paper present three-dimensional time varing magnetic field analysis method using electric field E and magnetic scarlar potential $\Omega$, and examine sample model.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.695-698
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• 2005

The finite-field multiplication can be applied to the wide range of applications, such as signal processing on communication, cryptography, etc. However, an efficient algorithm and the hardware design are required since the finite-field multiplication takes much time to compute. In this paper, we propose a radix-4 systolic multiplier on $GF(2^m)$ with comparative area and performance. The algorithm of the proposed standard-basis multiplier is mathematically developed to map on low-cost systolic cell, so that the proposed systolic architecture is suitable for VLSI design. Compared to the bit-serial and digit-serial multipliers, the proposed multiplier shows relatively better performance with low cost. We design and synthesis $GF(2^{193})$ finite-field multiplier using Hynix $0.35{\mu}m$ standard cell library and the maximum clock frequency is 400MHz.