• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.195-198
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• 2000

It is possible to perform the digital fuzzy logical high-speed and high-precision computation by the use of redundantly-represented binary positive-digit number arithmetic operation. In this paper, as basic operation circuits in the fuzzy logic new voltage-mode 4-valued binary parallel processing operation circuits using positive redundantly-expressed binary-coded numbers is discussed.

• Communications for Statistical Applications and Methods
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• v.17 no.6
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• pp.803-810
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• 2010

The singular value decomposition of a rectangular matrix is a basic tool to understand the structure of the data and particularly the relationship between row and column factors. However, conventional singular value decomposition used the least squares method and is not robust to outliers. We propose a simple robust singular value decomposition algorithm based on the weighted least absolute deviation which is not sensitive to leverage points. Its implementation is easy and the computation time is reasonably low. Numerical results give the data structure and the outlying information.

• Nonlinear Functional Analysis and Applications
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• v.26 no.4
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• pp.649-662
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• 2021

Recently the author studied a one-parameter family of divergences and considered the related median minimization problem of finite points over these divergences in general symmetric cones. In this article, to utilize the results practically, we deal with a special symmetric cone called second order cone, which is important in optimization fields. To be more specific, concrete computations of divergences with its gradients and the unique minimizer of the median minimization problem of two points are provided skillfully.

• The Mathematical Education
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• v.47 no.1
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• pp.11-25
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• 2008

The characteristics of the pseudo-conceptual or the pseudo-analytical behaviors according to the achievement level(i.e. advanced group, proficient group, basic group, and below-basic group) in grade 9 are as follows. The pseudo-conceptual or pseudo-analytical behaviors to get credit from teachers become conspicuous in lower achievement level. The high achieving students showed more pseudo-conceptual or pseudo-analytical behaviors without undergoing the process of reflection or control. The proficient group was short of control in computation, and the advanced group didn't control well in representation. The proficient group tended to depend on a past successful algorithm and behave habitually. Therefore, it is needed to teach mathematics according to the characteristic of pseudo-conceptual or pseudo-analytic behaviors shown in each achievement level.

• Structural Engineering and Mechanics
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• v.7 no.2
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• pp.159-180
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• 1999

The present paper shows a new non-tensorial approach to derive basic equations for various structural analyses. It can be used directly in numerical computation procedures. The aim of the paper is, however, to show that the approach serves as an excellent tool for analytical purposes also, working as a link between analytical and numerical techniques. The paper gives a method to derive, at first, expressions for strains in general beam and shell analyses, and secondly, the governing equilibrium equations. The approach is based on the utilization of local fixed Cartesian coordinate systems. Applying these, all the definitions required are the simple basic ones, well-known from the analyses in common global coordinates. In addition, the familiar principle of virtual work has been adopted. The method will be, apparently, most powerful in teaching the theories of curved beam and shell structures for students not familiar with tensor analysis. The final results obtained have no novelty value in themselves, but the procedure developed opens through its systematic and graphic progress a new standpoint to theoretical considerations.

• The Mathematical Education
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• v.44 no.4 s.111
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• pp.587-602
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• 2005

The primary purpose of this study was to investigate how number sense performance of sixth graders was and what every character of five components of number sense possessed by sixth graders was. For the this purpose, Two kinds of studies were conducted : a descriptive study by pencil-and-paper tests(Basic Test, Number Sense Test) and a clinical study by interviews. The conclusions drawn from the results obtained in the this study were as follows : First, students were highly scored in Basic Test but not highly scored equally in Number Sense Test. Second, students hardly used the benchmarks and lacked consideration of the reasonableness about computation results. Interview results were that students' notion about the meaning, and the greater - than and less - than relations for fractions was weak and students tended to not use number sense but apply standard algorithm and compute numbers in the question without thinking.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.206-211
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• 1993

The explicit scheme for finite element analysis of sheet metal forming problems has been widely used for providing practical solution since it improves the convergency problem,memory size and computational time especially for the case of complicated geometry and large element number. In the present work, a basic formulation for rigid-plastic explicit finite element analysis of plain strain sheet metal forming problems has been proposed. The effect of some basic parameters involved in the dynamic analysis has been studied in detail. A direct trial-and-error method is introduced to treat contact and friction. In order to show the validity and effectiveness of the proposed explicit scheme, computation are carried out for cylindrical punch stretching and the computational results are compared with those by the implicit scheme as well as with a commercial code. The proposed rigid-plastic explicit element method can be used as a robust and efficient computational method for analysis of sheet method forming.

• Structural Engineering and Mechanics
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• v.27 no.6
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• pp.683-696
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• 2007

This article is concerned with the presentation of a time-domain BEM approach applied to the solution of the scalar wave equation for 2D problems. The basic idea is quite simple: the basic variables of the problem at time $t_n$ (potential and flux) are computed with the results related to the potential and to its time derivative at time $t_{n-1}$ playing the role of "initial conditions". This time-marching scheme needs the computation of the potential and its time derivative at all boundary nodes and internal points, as well as the entire discretization of the domain. The convolution integrals of the standard time-domain BEM formulation, however, are not computed; the matrices assembled, only at the initial time interval, are those related to the potential, flux and to the potential time derivative. Two examples are presented and discussed at the end of the article, in order to verify the accuracy and potentialities of the proposed formulation.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.1
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• pp.33-40
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• 2023

With the development of supercomputing technology and hardware technology, numerical computation methods are also being advanced. Accordingly, improved weather prediction becomes possible. In this paper, we propose to apply the LAPACK(Linear Algebra PACKage) BLAS(Basic Linear Algebra Subprograms) library to the linear algebraic numerical computation part within the source code to improve the performance of the cumulative parametric code, Unicon(A Unified Convection Scheme), which is included in SCAM(Single-Columns Atmospheric Model, simplified version of CESM(Community Earth System Model)) and performs standby operations. In order to analyze this, an overall execution structure diagram of SCAM was presented and a test was conducted in the relevant execution environment. Compared to the existing source code, the SCOPY function achieved 0.4053% performance improvement, the DSCAL function 0.7812%, and the DDOT function 0.0469%, and all of them showed a 0.8537% performance improvement. This means that the LAPACK BLAS application method, a library for high-density linear algebra operations proposed in this paper, can improve performance without additional hardware intervention in the same CPU environment.

• Journal of the Korea Convergence Society
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• v.11 no.6
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• pp.7-14
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• 2020

A Battery Monitoring System capable of State-of-Charge(SOC) estimation using the Extended Kalman Filter(EKF) is described in this paper. In order to accurately estimate the SOC of the battery, the battery cells were modeled as the Thevenin equivalent circuit model. The Thevenin model's parameters were measured in experiments. For the Battery Monitoring System, we designed a battery monitoring device that can calculate the SOC estimation using the EKF and a monitoring server that controls multiple battery monitoring devices. We also develop a web-based dashboard for controlling and monitoring batteries. Especially the computation of the monitoring server could be reduced by calculating the battery SOC estimation at each Battery Monitoring Device.