• Journal of the Korean Mathematical Society
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• v.47 no.4
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• pp.861-877
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• 2010

The works of Erd$\ddot{o}$s et al. about expansions of 1 with respect to a non-integer base q, referred to as q-expansions, are investigated to determine how far they continue to hold when the number 1 is replaced by a positive number x. It is found that most results about q-expansions for real numbers greater than or equal to 1 are in somewhat opposite direction to those for real numbers less than or equal to 1. The situation when a real number has a unique q-expansion, and when it has exactly two q-expansions are studied. The smallest base number q yielding a unique q-expansion is determined and a particular sequence is shown, in certain sense, to be the smallest sequence whose corresponding base number q yields exactly two q-expansions.

• Communications of the Korean Mathematical Society
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• v.21 no.4
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• pp.779-786
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• 2006

Let $\mathbb{X}_t$ be an m-dimensional linear process defined by $\mathbb{X}_t=\sum{_{j=0}^\infty}\;A_j\;\mathbb{Z}_{t-j}$, t = 1, 2, $\ldots$, where $\mathbb{Z}_t$ is a sequence of m-dimensional random vectors with mean 0 : $m\times1$ and positive definite covariance matrix $\Gamma:m{\times}m$ and $\{A_j\}$ is a sequence of coefficient matrices. In this paper we give sufficient conditions so that $\sum{_{t=1}^{[ns]}\mathbb{X}_t$ (properly normalized) converges weakly to Wiener measure if the corresponding result for $\sum{_{t=1}^{[ns]}\mathbb{Z}_t$ is true.

• East Asian mathematical journal
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• v.36 no.1
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• pp.61-71
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• 2020

Up to the present day, the best solution we can get to the truncated moment problem (TMP) is probably the Flat Extension Theorem. It says that if the corresponding moment matrix of a moment sequence admits a rank-preserving positive extension, then the sequence has a representing measure. However, constructing a flat extension for most higher-order moment sequences cannot be executed easily because it requires to allow many parameters. Recently, the author has considered various decompositions of a moment matrix to find a solution to TMP instead of an extension. Using a new approach with the Hadamard product, the author would like to introduce more techniques related to moment matrix decompositions.

• Korean Journal of Child Studies
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• v.19 no.2
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• pp.133-146
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• 1998

This study was designed to assess the developmental sequence of children's understanding of social interaction and to test the effects of support conditions and behavioral domains on the understanding of social interaction. The subjects were one hundred 4- to 8-year-old children. The method was a doll play situation, composed of three different support conditions. Scalogram analysis was used to test the developmental sequence, and ANOVA and paired t-test were used to test the significance of differences in stages. The results of this study evidenced a sequential pattern in the 4- to 8-year-old children's understanding of social interaction. There were also significant differences between stages in the understanding of social interaction according to support conditions and behavioral domains. Higher levels of support produced higher stages of understanding and the understanding of positive social interactions were higher than those of negative social interactions at ages 4 and 5.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.145-147
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• 2002

In this paper, the improved fault locating method using distributed parameter which calculating the reduced voltage and current according to the ground capacitance in long transmission line was proposed. For the purpose of the fault locating algorithm non influenced source impedance, the loop method was used in the system modeling analysis. To enhance the fault locating, zero sequence of the fault current which is variable according to ground capacitance was not used but positive and negative sequence. System model was simulated using EMTP software. To verify the accuracy of proposed method, in different cases 64 sampled data per cycle was used and 160km and 300km long transmission line has fault resistance $0{\Omega}\;and\;100{\Omega}$ respectively was compared.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1186-1188
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• 1999

When we perform the test related to the power distribution system such as artificial fault test, protective coordination test, distribution automation test in short length test line, Lumped Constant Circuit, a kind of variable impedance, should be attached to the test line in order to make it equivalent to a real line in length electrically. In this paper we designed the positive sequence and zero sequence Lumped Constant Circuit with optimized inductor and resister for the modification of long, 16km, distribution line, when they are attached to the short, 4km, distribution test line.

• BMB Reports
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• v.31 no.6
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• pp.525-535
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• 1998

A critical step in the faithful translation of genetic information is specific tRNA recognition by aminoacyl-tRNA synthetases. These enzymes catalyze the covalent attachment of particular amino acids to the terminal adenosine of cognate tRNA substrates. In general, there is one synthetase for each of the twenty amino acids and each enzyme must discriminate against all of the cellular tRNAs that are specific for the nineteen noncognate amino acids. Primary sequence information combined with structural data have resulted in the division of the twenty synthetases into two classes. In recent years, several high-resolution co-crystal structures along with biochemical data have led to an increased understanding of tRNA recognition by synthetases of both classes. The anticodon sequence and the amino acid acceptor stem are the most common locations for critical recognition elements. This review will focus on acceptor stem discrimination by class II synthetases. In particular, the results of in vitro aminoacylation assays and site-directed and atomic group mutagenesis studies will be discussed. These studies have revealed that even subtle atomic determinants can provide signals for specific tRNA aminoacylation.

• Journal of applied mathematics & informatics
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• v.30 no.5_6
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• pp.903-911
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• 2012

Let $\{u(t)\}$ and $\{u(dt)\}$ be two maximal length sequences of period $2^n-1$. The cross-correlation is defined by $C_d({\tau})=\sum{_{t=0}^{2^n-2}}(-1)^{u(t+{\tau})+v(t)$ for ${\tau}=0,1,{\cdots},2^n-2$. In this paper, we propose a new proof for finding the values and the number of occurrences of each value of $C_d({\tau})$ when $d=2^{k-2}(2^k+3)$, where $n=2k$, $k$ is a positive integer.

• Journal of applied mathematics & informatics
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• v.16 no.1_2
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• pp.243-249
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• 2004

Our aim in this paper is to investigate the global attractivity of the recursive sequence $x_{n+1}\;=\;\frac{{\alpha}\;-\;{\beta}x_{n-\kappa}}{{\gamma}+x_n}$, where ${\alpha},\;{\beta},\;{\gamma}\;>\;0\;and\;{kappa}\;=\;1,\;2,\;{\ldots}$ We show that the positive equilibrium point of the equation is a global attractor with a basin that depends on certain conditions posed on the coefficients.

• Journal of Life Science
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• v.8 no.4
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• pp.360-365
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• 1998

The genetic of a recently described virus, hepatitis G virus(HGV) was investigated. HGV envelope 1 (E1) nucleotide sequences isolated from six Korean hepatitis b virus-positive patients by using a reverse transcription-poly-merase chain reaction procedure, were analysed and compared to the seven previously reported HGV isolates. Sequence homology among the Korean isolates was 88-97% whereas among the isolates from different geographic areas was 80-92%, indicating geographical divergence of HGV. Nucleotide substitutions spread uniformly throughiut the E1 fragment. Furthermore, compared to the prototype HGV sequence, frameshift mutations were observed in most of the Korean isolating that a different translating initiation site for the polyprotein exists in the Korean type HGV.