• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.1
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• pp.53-63
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• 1986

In this paper the decoder of nonbinary code satisfying R>1/t has been designed and constructed, where R is the code rate and t is the error correcting capability. In order to design the error trapping decoder, the concept of covering monomial is used and them the decoder system using the (15, 11) Reed-Solomon code is implemented. Without Galois Fiedl multiplication and division circuits, the decoder system is simply constructed. In the decoding process, it takes 60clocks to decode one code word. Two symbol errors and eight binary burst errors are simultaneously corrected. This coding system is shown to be efficient when the channel error probability is approximately from $5{\times}10^-4$~$5{\times}10^-5$.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1996.11a
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• pp.286-294
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• 1996

In a remarkable paper 〔3〕, Hammons et al. showed that, when properly defined, the binary nonlinear Preparata code can be considered as the Gray map of a linear code eve. Z$_4$, the so-called Preparata code eve. Z$_4$. Recently, Yang and Helleseth 〔12〕 considered the generalized Hamming weights d$\_$r/(m) for Preparata codes of length 2$\^$m/ over Z$_4$ and exactly determined d$\_$r/, for r = 0.5,1.0,1.5,2,2.5 and 3.0. In particular, they completely determined d$\_$r/(m) for any r in the case of m $\leq$ 6. In this paper we show that the Preparata code of length 16 over Z$_4$ does not satisfy the chain condition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.8
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• pp.703-709
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• 2017

Creep analysis takes much more time than elastic or elastic-plastic analysis. In this study, we conducted elastic and elastic-plastic analysis and compared the results with creep analysis results. In the elastic analysis, we used primary stress, which can be classified by the $M{\alpha}-tangent$ method and stress intensities recommended in the ASME code. In the elastic-plastic analysis, we calculated the parameters recommended in the R5 code. For the FE models, a bending load, uniaxial load, and biaxial load were applied to the cross shaped welded plate, and a bending load and internal pressure were applied to the elbow pipe. To investigate the element size sensitivity, we conducted FE analysis for various element sizes for the cases where bending load was applied to the cross shaped welded plate. There was no significant difference between the creep stress and the alternative methods; however, in the $M{\alpha}-tangent$ method, the results were affected by the element size.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.5
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• pp.631-640
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• 2013

This paper provides a comparison of the J-integral estimation method under combined primary and secondary stress in the R6, RCC-MR A16 code. The comparisons of each code are based on finite element analysis using ABAQUS with regard to the crack shape, crack depth, and magnitude of secondary load. The estimate of the R6 code is conservative near $L_r=1$, and that of the RCC-MR A16 code is conservative near $L_r=0$. As a result, this paper proposes a modified method of J-integral estimation in the R6, RCC_MR A16 code. The J-integral using the modified method corresponds to the finite element analysis result.

• Journal of the Korean earth science society
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• v.45 no.4
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• pp.292-303
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• 2024

We study quasi-spherical, supersonic accretion flows around black holes using high-accuracy numerical simulations. We describe a code, the Lagrangian Total Variation Diminishing (TVD), and a remap routine to address a specific issue in the Advection Dominated Accretion Flow (ADAF) that is, appropriately handling the angular momentum even near the inner boundary. The Lagrangian TVD code is based on an explicit finite difference scheme on mass-volume grids to track fluid particles with time. The consequences are remapped on fixed grids using the explicit Eulerian finite-difference algorithm with a third-order accuracy. Test results show that one can successfully handle flows and resolve shocks within two to three computational cells. Especially, the calculation of a hydrodynamical accretion disk without viscosity around a black hole shows that one can conserve nearly 100% of specific a ngular momentum in one-and two-dimensional cylindrical coordinates. Thus, we apply this code to obtain a numerically similar ADAF solution. We perform simulations, including viscosity terms in one-dimensional spherical geometry on the non-uniform grids, to obtain greater quantitative consequences and to save computational time. The error of specific angular momentum in Newtonian potential is less than 1% between r~10r_s and r~10⁴ r_s, where r_s is sink size. As Narayan et al. (1997) suggested, the ADAFs in pseudo-Newtonian potential become supersonic flows near the black hole, and the sonic point is r_sonic~5.3r_g for flow with α =0.3 and γ=1 .5. Such simulations indicate that even the ADAF with γ=5/3 is differentially rotating, as Ogilvie (1999) indicated. Hence, we conclude that the Lagrangian TVD and remap code treat the role of viscosity more precisely than the other scheme, even near the inner boundary in a rotating accretion flow around a nonrotating black hole.

• Convergence Security Journal
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• v.19 no.3
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• pp.37-41
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• 2019

Recently, due to the appearance of various types of malware, the existing static analysis exposes many limitations. Static analysis means analyzing the structure of a code or program with source code or object code without actually executing the (malicious) code. On the other hand, dynamic analysis in the field of information security generally refers to a form that directly executes and analyzes (malware) code, and compares and examines and analyzes the state before and after execution of (malware) code to grasp the execution flow of the program. However, dynamic analysis required analyzing huge amounts of data and logs, and it was difficult to actually store all execution flows. In this paper, we propose and implement a preprocessor architecture of a system that performs malware detection and real-time multi-dynamic analysis based on 2nd generation PT in Windows environment (Windows 10 R5 and above).

• The Journal of the Korea Contents Association
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• v.5 no.4
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• pp.150-159
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• 2005

With the increase of interest in ubiquitous computing, image code is attracting attention in various areas. Image code is important in ubiquitous computing in that it can complement or replace RFID (radio frequency identification) in quite a few areas as well as it is more economical. However, because of the difficulty in reading precise colors due to the severe distortion of colors, its application is quite restricted by far. In this paper, we present an efficient method of image code recognition including automatically locating the image code using the hue and saturation values. In our experiments, we use an image code whose design seems most practical among currently commercialized ones. This image code uses six safe colors, i.e., R, G, B, C, M, and Y. We tested for 72 true-color field images with the size of $2464{\times}1632$ pixels. With the color calibration based on the histogram, the localization accuracy was about 96%, and the accuracy of color classification for localized codes was about 91.28%. It took approximately 5 seconds to locate and recognize the image code on a PC with 2 GHz P4 CPU.

• Journal of the Institute of Convergence Signal Processing
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• v.15 no.2
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• pp.48-54
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• 2014

For the element ${\alpha}{\in}GF(p^n)$, two kinds of bases are known. One is a conventional polynomial basis of the form $\{1,{\alpha},{\alpha}^2,{\cdots},{\alpha}^{n-1}\}$, and the other is a normal basis of the form $\{{\alpha},{\alpha}^p,{\alpha}^{p^2},{\cdots},{\alpha}^{p^{n-1}}\}$. In this paper we consider the method of generating normal bases which construct the finite field $GF(p^n)$, as an n-dimensional extension of the finite field GF(p). And we analyze the code sequence generating algorithm and derive the implementation functions of code sequence generator based on the normal bases. We find the normal polynomials of degrees, n=5 and n=7, which can generate normal bases respectively, design, and construct the code sequence generators based on these normal bases. Finally, we produce two code sequence groups(n=5, n=7) by using Simulink, and analyze the characteristics of the autocorrelation function, $R_{i,i}(\tau)$, and crosscorrelation function, $R_{i,j}(\tau)$, $i{\neq}j$ between two different code sequences. Based on these results, we confirm that the analysis of generating algorithms and the design and implementation of the code sequence generators based on normal bases are correct.

• Earthquakes and Structures
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• v.16 no.2
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• pp.185-196
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• 2019

One of the shortcomings of seismic bridge design codes is the lack of clarity in defining the role of different seismic isolation systems with linear or nonlinear behavior in terms of R-factor. For example, based on AASHTO guide specifications for seismic isolation design, R-factor for all substructure elements of isolated bridges should be half of those expressed in the AASHTO standard specifications for highway bridges (i.e., R=3 for single columns and R=5 for multiple column bent) but not less than 1.50. However, no distinction is made between two commonly used types of seismic isolation devices, i.e., elastomeric rubber bearing (ERB) with linear behavior, and lead rubber bearing (LRB) with nonlinear behavior. In this paper, five existing bridges located in Iran with two types of deck-pier connection including ERB and LRB isolators, and two bridge models with monolithic deck-pier connection are developed and their R-factor values are assessed based on the Uang's method. The average R-factors for the bridges with ERB isolators are calculated as 3.89 and 4.91 in the longitudinal and transverse directions, respectively, which are not in consonance with the AASHTO guide specifications for seismic isolation design (i.e., R=3/2=1.5 for the longitudinal direction and R=5/2=2.5 for the transverse direction). This is a clear indicator that the code-prescribed R-factors are conservative for typical bridges with ERB isolators. Also for the bridges with LRB isolators, the average computed R-factors equal 1.652 and 2.232 in the longitudinal and transverse directions, respectively, which are in a good agreement with the code-specified R-factor values. Moreover, in the bridges with monolithic deck-pier connection, the average R-factor in the longitudinal direction is obtained as 2.92 which is close to the specified R-factor in the bridge design codes (i.e., 3), and in the transverse direction is obtained as 2.41 which is about half of the corresponding R-factor value in the specifications (i.e., 5).

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.273-276
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• 2000

Recently, Turbo code has been considered for channel coding in IMT-2000(International Mobile Telecommunication-2000) system, because it offers better error correcting capability than the traditional convolution/viterbi coding . In this paper, a turbo code decoder for speech transmission in IMT-2000 system with frame size 192 bits, constrait length K=3, generator polynomials G(5,7) and code rate R=1/3 is designed using SOVA(Soft Output Viterbi Algorithm) and block interleaver