• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.133-134
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• 2006

In this paper, a novel method is presented for efficient calculation of the spatial-domain Green's functions of 2D electromagnetic problems. This method combines spectral and spatial domain calculation schemes and prevents the Green's functions from diverging at the singularities that complicate the process of the Method of Moment(MoM) application. For the validation of this proposed method, fields will be evaluated along the spatial distance including zero distance for 2D free-space and periodic homogeneous geometry. The numerical results show the validity of the prosed method and correspondng physics.

• Journal of the Chungcheong Mathematical Society
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• v.17 no.1
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• pp.47-56
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• 2004

The nonlinearity of a Boolean function f on $GF(2)^n$ is the minimum hamming distance between f and all affine functions on $GF(2)^n$ and it measures the ability of a cryptographic system using the functions to resist against being expressed as a set of linear equations. Finding out the exact value of the nonlinearity of given Boolean functions is not an easy problem therefore one wants to estimate the nonlinearity using extra information on given functions, or wants to find a lower bound or an upper bound on the nonlinearity. In this paper we extend the notion of auto-correlations of Boolean functions to vector Boolean functions and obtain upper bounds and a lower bound on the nonlinearity of vector Boolean functions in the context of their auto-correlations. Also we can describe avalanche characteristics of vector Boolean functions by examining the extended notion of auto-correlations.

• Bulletin of the Korean Mathematical Society
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• v.36 no.2
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• pp.287-303
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• 1999

The general solution of the functional equation f1(pr, qs) + f2(ps, qr) = g(p,q) + h(r,s) for p, q, r, s $\in$] 0, 1[will be investigated without any regularity assumptions on the unknown functions f1, f2, g, h:]0.1[->R.

• Communications of the Korean Mathematical Society
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• v.27 no.4
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• pp.753-762
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• 2012

We prove some sharp extremal distance results for functions in weighted Bergman spaces on the upper halfplane. We also prove new analogous results in the context of bounded strictly pseudoconvex domains with smooth boundary.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.299-306
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• 2011

In this paper, a blind adaptive equalization algorithm based on PDF-distance minimization and a set of Delta functions is introduced and its superior robustness against impulsive noise and multipath characteristics of underwater communication channels is proved. The conventional CMA based on MSE has shown to be incapable of coping with impulsive noise, and correntropy blind algorithm has also revealed to yield not satisfying performance for the mission. On the other hand, the blind adaptive equalization algorithm based on PDF-distance minimization and a set of Delta functions has been proved to solve effectively the problem of impulsive noise and multipath characteristics of underwater communication channels through theoretical and simulation analysis.

• Communications of the Korean Mathematical Society
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• v.33 no.1
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• pp.85-101
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• 2018

Let S be a polynomial ring over a field K, with a monomial order ${\prec}$, and let I be an unmixed graded ideal of S. In this paper we study two functions associated to I: The minimum distance function ${\delta}_I$ and the footprint function $fp_I$. It is shown that ${\delta}_I$ is positive and that $fp_I$ is positive if the initial ideal of I is unmixed. Then we show that if I is radical and its associated primes are generated by linear forms, then ${\delta}_I$ is strictly decreasing until it reaches the asymptotic value 1. If I is the edge ideal of a Cohen-Macaulay bipartite graph, we show that ${\delta}_I(d)=1$ for d greater than or equal to the regularity of S/I. For a graded ideal of dimension ${\geq}1$, whose initial ideal is a complete intersection, we give an exact sharp lower bound for the corresponding minimum distance function.

• Journal of Magnetics
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• v.20 no.1
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• pp.11-20
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• 2015

In this work, Monte Carlo simulation was employed to model the stretchable Ising monolayer film to investigate the effect of the spatial distance variation among magnetic atoms on magnetic behavior of the film. The exchange interaction was considered as functions of initial interatomic distance and the stretched distance (or the strain). Following Bethe-Slater picture, the magnetic exchange interaction took the Lennard-Jones potential-like function. Monte Carlo simulations via the Wolff and Metropolis algorithms were used to update the spin systems, where equilibrium and dynamic magnetic profiles were collected. From the results, the strain was found to have strong influences on magnetic behavior, especially the critical behavior. Specifically, the phase transition point was found to either increase or decrease depending on how the exchange interaction shifts (i.e. towards or away from the maximum value). In addition, empirical functions which predict how the critical temperatures scale with initial interatomic distance and the strain were proposed, which provides qualitatively view how to fine tune the magnetic critical point in monolayer film using the substrate modification induced strain.

• Journal of the Korean Data and Information Science Society
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• v.14 no.3
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• pp.687-696
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• 2003

This article presents a new family of the estimating functions related with minimum distance estimations, and discusses its relationship to the family of the minimum density power divergence estimating equations. Two representative minimum distance estimations; the minimum $L_2$ distance estimation and the minimum Hellinger distance estimation are studied in the light of the theory of estimating equations. Despite of the desirable properties of minimum distance estimations, they are not widely used by general researchers, because theories related with them are complex and are hard to be computationally implemented in real problems. Hopefully, this article would be a help for understanding the minimum distance estimations better.

• Communications for Statistical Applications and Methods
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• v.27 no.6
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• pp.589-602
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• 2020

The development of smart grids has enabled the easy collection of a large amount of power data. There are some common patterns that make it useful to cluster power consumption patterns when analyzing s power big data. In this paper, clustering analysis is based on distance functions for time series and clustering algorithms to discover patterns for power consumption data. In clustering, we use 10 distance measures to find the clusters that consider the characteristics of time series data. A simulation study is done to compare the distance measures for clustering. Cluster validity measures are also calculated and compared such as error rate, similarity index, Dunn index and silhouette values. Real power consumption data are used for clustering, with five distance measures whose performances are better than others in the simulation.

• International Journal of Computer Science & Network Security
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• v.21 no.5
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• pp.69-72
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• 2021

The article discusses the features of the use of distance technologies to intensify the learning process of students. The advantages and disadvantages of distance learning are shown. The role and functions of the teacher in distance learning have been adjusted. Information and methodological support for distance learning of students is proposed. Analyzed pedagogical, psychological, methodological and philosophical literature, educational standards, charters of higher educational institutions and other documents. Studied foreign experience in conducting classes using information technology.