• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.247-249
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• 2017

NIST에서 표준으로 정의된 P-192, P-224, P-256, P-384 타원곡선 상의 스칼라 곱셈(scalar multiplication) 연산을 지원하는 Scalable 타원곡선 암호(Elliptic Curve Cryptography; ECC) 프로세서의 설계에 대해 기술한다. 투영(projective) 좌표계를 이용하여 하드웨어 자원 소모가 큰 나눗셈 연산을 제거하였으며, GF(p) 상의 덧셈, 뺄셈, 곱셈 등의 유한체 연산을 지원한다. 워드 기반 몽고메리 곱셈기를 이용하여 다양한 크기의 필드(field)에서 고정된 하드웨어 자원을 통하여 곱셈 연산을 수행하도록 하였으며, 필드의 크기에 따라 연산 사이클이 증가하거나 감소한다. 설계된 Scalable ECC 프로세서는 Verilog HDL로 모델링 되었으며, Modelsim을 이용한 기능검증을 하였다. Xilinx Virtex5 FPGA 디바이스 합성결과 5,376-비트 RAM과 970 슬라이스로 구현되었으며, 최대 55 MHz의 동작 주파수를 갖는다.

• The Korean Journal of Malacology
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• v.29 no.2
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• pp.121-127
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• 2013

In this study, growth-line analysis was carried out on the hard clam (Meretrix petechialis) collected from the Neolithic shell middens in Daejuk-ri, Seosan, Korea, to reconstruct palaeoenvironment. Growth increments of 206 specimens of the clam were examined. The ages of the specimens were determined from the rings on the shells. The relationship between shell length and ring radius in each ring group was expressed as a regression line, indicating a correspondence in each ring formation. Growth pattern of the midden specimens was compared to that of modern ones collected from Gimje, Jeonbuk. Growth curves for shell length fitted to the von Berta anffy's growth curve were expressed respectively as follows: $SL_t=102.9025[1-e^{-0.18657(t+1.0906)}]$ in the shell midden specimens, $SL_t=104.2583[1-e^{-0.2277(t+0.7499)}]$ in the modern ones. The relationship between shell length (SL; mm) and shell height (SH; mm) was expressed by the following equations: SH = 0.7791 SL + 3.6636 ($R^2$ = 0.946) in the midden specimens, SH = 0.8103 SL + 0.5145 ($R^2$ = 0.991) in the modern ones. The results of the tests regarding the differences between regression coefficients and elevations of growth curves of these two populations demonstrate that the slopes were not significantly different (p < 0.05), but the elevations were (p > 0.05). However, overall growth curves of the midden and modern populations were not significantly different, indicating that shell growth environments of the two areas are similar. Therefore, it is likely that sea temperature near the midden area could be similar to that of present Gimje area, and thus temperature during the period of the midden formation could be higher than presently known.

• Journal of Korean Society of Forest Science
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• v.99 no.1
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• pp.131-135
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• 2010

This study was carried out to establish a proper cultivation condition and diagnose the drought-tolerance of three wild edible greens belonging to genus of Ligularia by using pressure-volume curves methods. The result of the original bulk osmotic pressure at maximum turgor ${\Psi}_{\circ}{^{sat}}$ was -0.8 MPa in Ligularia fischeri and L. stenocephala, which was somewhat lower than the value, -0.7 MPa, in L. fischeri var. spiciformis. In addition, the values of the osmotic pressure at incipient plasmolysis ${\Psi}_{\circ}{^{tlp}}$ in L. fischeri and L. stenocephala, both of which were -0.9 MPa, These were slightly lower than that of -0.8 MPa in L. fischeri var. spiciformis. On the other hand, it appeared that the values of maximum bulk modulus of elasticity $E_{max}$ of L. fischeri and L. stenocephala were approximately two times higher than that of L. fischeri var. spiciformis. However, There was a distinct difference between the values of the relative water contents in these three species. Therefore, Ligularia spp, occurring incipient plasmolysis in the high water contents, have a relatively low property of drought-tolerance, suggesting that growth of those Ligularia spp. are appropriate for relative moisture forest.

• Journal of the Korean Geotechnical Society
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• v.31 no.2
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• pp.47-63
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• 2015

A fundamental study of drilled shafts subjected to lateral cyclic loading in weathered soil was carried out based on field tests and numerical analysis. The emphasis was given on quantifying the cyclic p-y curve function from lateral cyclic loading tests and three-dimensional finite element analysis. Lateral cyclic loading tests and three-dimensional finite element analysis were carried out to investigate the behavior of drilled shafts according to the direction of cyclic loading. Based on the field tests and numerical analysis, a modified lateral load transfer relationship and design chart with degradation factors were proposed by considering the characteristics of cyclic loading. It was found that the prediction by the proposed p-y curve function is in good agreement with the general trends observed by in-situ measurements, and it represents a practical improvement in the prediction of lateral displacement and bending moment distribution of drilled shafts subjected to cyclic loading.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.877-883
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• 2009

Shaking table tests are performed to evaluate the dynamic group pile effect in fine sand. Single pile tests and $2{\times}4$ group pile tests are performed on 3D pile spacing. Dynamic p-y backbone curves are obtained to evaluate dynamic group pile effect by using dynamic p-y curve of single pile. And dynamic group pile p-multiplier is estimated by dynamic p-y backbone curve. Dynamic p-multiplier can be calculated by using subground reaction ratio of dynamic p-y backbone curve which is the same displacement of p-y curve peak point As the result, dynamic group pile effects are evaluated in terms of a shaking frequency, a shaking acceleration, and a relative density. Dynamic group pile p-multiplier is the largest at lead pile, and the value decrease at middle pile and trail pile. p multiplier increases as increasing input acceleration and decreasing relative density. This results coincide with NCHRP's research which suggest p multiplier increases as increasing pile cap displacement.

• Analytical Science and Technology
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• v.18 no.2
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• pp.168-172
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• 2005

A comparison study of XRF and $^{31}P$-NMR method for the analysis of phosphorous in lubricating oil has been described. Pure oil and water were used for the observation of matrices effect variation by different analytical methods. Quantitative analysis was carried out by XRF and $^{31}P$-NMR using real samples. Significant difference is observed from the slopes on the calibration curves by the XRF due to the matrices (water: 124.0, oil: 276.6). While the result obtained from XRF showed a large matrix effect, the slopes obtained from $^{31}P$-NMR results of two different matrices, however, are in good agreement ranged of ${\pm}9%$ (water: 4.9, oil: 5.3).

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.365-372
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• 2004

A new finite element model will be presented to analyze the nonlinear behavior of not only RC beams and slabs, but also RC beams strengthened by a patch repair. The numerical approach is based on the p-version degenerate shell element including theory of anisotropic laminated composites, theory of materially and geometrically nonlinear plates. In the nonlinear formulation of this model, the total Lagrangian formulation is adopted with large deflections and moderate rotations being accounted for in the sense of von Karman hypothesis. The material model is based on hardening rule, crushing condition, plate-end debonding strength model and so on. The Gauss-Lobatto numerical quadrature is applied to calculate the stresses at the nodal points instead of Gauss points. The validity of the proposed p-version finite element model is demonstrated through several numerical examples for the load-deflection curves, the ultimate loads, and the failure modes of reinforced connote slabs and RC beams bonded with steel plates or FRP plates compared with available experimental and numerical results.

• Bulletin of the Korean Mathematical Society
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• v.55 no.3
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• pp.763-776
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• 2018

In this paper we consider the element-wise (Hadamard) product (or sum) of elliptic divisibility sequences and study the periodic structure of these sequences. We obtain that the element-wise product (or sum) of elliptic divisibility sequences are periodic modulo a prime p like linear recurrence sequences. Then we study periodicity properties of product sequences. We generalize our results to the case of modulo $p^l$ for some prime p > 3 and positive integer l. Finally we consider the p-adic behavior of product sequences and give a generalization of [9, Theorem 4].

• Journal of Astronomy and Space Sciences
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• v.11 no.2
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• pp.175-184
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• 1994

RI photometric observations of an extreme long period eclipsing binary star AZ Cas have been made at the Yonsei University Observatory using the 60-cm Goto reflector for three seasons from 1990 to 1993. A total of 884 observations are made for 77 nights. All the data are standardized and determined the magnitudes and colors of AZ Cas. No significant light variation at the outside eclipse phase between $0.^p54$∼$0.^p87$. RI and color curves of AZ Cas are presented.

• Proceedings of the KIEE Conference
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• 1999.11a
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• pp.35-42
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• 1999

As our power system has changed the past undeveloped model causing the lacked supply of power to the civilized model that the remained one makes the voltage and the frequency rise at the middle of the night, the leading power factor operation of generators, that is, the under-exited operation is essentially to be needed, so, at a viewpoint of the stability of the power system, it is a very important factor. In this investigation. the equation of curves for each area on the capability curve has been studied at the above-mentioned viewpoint. Also, each capability curve for the operating power stations (Nuclear P/S, Thermal P/S, Hydrolic & pumping-up P/S Gas turbine P/S) has, been presented, and studied whether the leading power factor operational area is able to be expanded or not.