• Journal of the Optical Society of Korea
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• v.10 no.3
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• pp.112-117
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• 2006

We experimentally investigated the transmission characteristics of 400 Gbit/s (10 Gbit/s ${\times}$ 40 channels) WDM signals with 100 GHz channel spacing over 323 km of installed NZ_DSF. The installed fiber has optical properties of 0.28 dB/km attenuation, 4.3 ps/nm/km dispersion, $0.083ps/nm^2/km$ dispersion slope and less than $0.05ps/km^{1/2}$ PMD coefficient. In this experiment, two cases of dispersion compensation schemes, the lumped type and the distributed type, were compared. The results implied that the distributed type dispersion compensation in which dispersion compensation devices are inserted at the end of the each span showed better transmission performance than the lumped one in which dispersion compensation devices are located at the transmitter and receiver sites. From the analysis of the experimental results, we verified that different transmission performance comes from the power penalty induced by XPM in the distributed scheme is lower than the lumped scheme case.

• Bulletin of the Korean Mathematical Society
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• v.48 no.3
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• pp.617-625
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• 2011

In [6], it was shown that hyponormality for Toeplitz operators with polynomial symbols can be reduced to classical Schur's algorithm in function theory. In [6], Zhu has also given the explicit values of the Schur's functions ${\Phi}_0$, ${\Phi}_1$ and ${\Phi}_2$. Here we explicitly evaluate the Schur's function ${\Phi}_3$. Using this value we find necessary and sufficient conditions under which the Toeplitz operator $T_{\varphi}$ is hyponormal, where ${\varphi}$ is a trigonometric polynomial given by ${\varphi}(z)$ = ${\sum}^N_{n=-N}a_nz_n(N{\geq}4)$ and satisfies the condition $\bar{a}_N\(\array{a_{-1}\\a_{-2}\\a_{-4}\\{\vdots}\\a_{-N}}\)=a_{-N}\;\(\array{\bar{a}_1\\\bar{a}_2\\\bar{a}_4\\{\vdots}\\\bar{a}_N}\)$. Finally we illustrate the easy applicability of the derived results with a few examples.

• Bulletin of the Korean Mathematical Society
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• v.51 no.1
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• pp.77-82
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• 2014

We prove that if ${\mid}a_1{\mid}$ is large and ${\mid}a_0{\mid}$ is small enough, then every approximate zero of power series equation ${\sum}^{\infty}_{n=0}a_nx^n$=0 can be approximated by a true zero within a good error bound. Further, we obtain Hyers-Ulam stability of zeros of the polynomial equation of degree n, $a_nz^n$ + $a_{n-1}z^{n-1}$ + ${\cdots}$ + $a_1z$ + $a_0$ = 0 for a given integer n > 1.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.426-429
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• 1997

This paper describes the relationship among physiological, behavioral signal, and subjective evaluation depending on arousal level. Nz and reaction time hall similar pattern with KSS level, but eyeblink rate was different from these two parameters. Eyeblink rate increased slowly from KSS level 1 to 5, and had high increasing rate at KSS 7. But it showed steep descent at KSS level 9. From the result of reaction time test, since human performance was decreased rapidly above the KSS level 5, it is desirable to give a subject some stimulus such as sound or aroma to rise arousal level above the KSS level 3.

• Journal of applied mathematics & informatics
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• v.36 no.3_4
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• pp.231-236
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• 2018

A polynomial, $p(z)=a_0z^n+a_1z^{n-1}+{\cdots}+a_{n-1}z+a_n$, with real coefficients is called a stable or a Hurwitz polynomial if all its zeros have negative real parts. We show that if a polynomial is a Hurwitz polynomial then so is the polynomial $q(z)=a_nz^n+a_{n-1}z^{n-1}+{\cdots}+a_1z+a_0$ (with coefficients in reversed order). As consequences, we give simple ratio checking inequalities that would determine unstability of a polynomial of degree 5 or more and extend conditions to get some previously known results.

• Honam Mathematical Journal
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• v.15 no.1
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• pp.75-85
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• 1993

For A and B, $-1{\leq}B<A{\leq}1$, let P[A, B] be the class of functions p analytic in the unit disk E with P(0) = 1 and subordinate to $\frac{1+Az}{1+Bz}$. We introduce the class $T_{\alpha}[A,B]$ of functions $f:f(z)=z+\sum\limits_{n=2}^{{\infty}}a_nz^n$ which are analytic in E and for $z{\in}E$, ${\alpha}{\geq}0$, $[(1-{\alpha}){\frac{f(z)}{z}}+{\alpha}f^{\prime}(z)]{\in}P[A,B]$. It is shown that, for ${\alpha}{\geq}1$, $T_{\alpha}[A,B]$ consists entirely of univalent functions and the radius of univalence for $f{\in}T_{\alpha}[A,B]$, $0<{\alpha}<1$ is obtained. Coefficient bounds and some other properties of this class are studied. Some radii problems are also solved.

• Journal of applied mathematics & informatics
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• v.36 no.5_6
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• pp.567-574
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• 2018

Let $f:f(z)=z+{\sum^{{\infty}}_{n=2}}a_nz^n$ be analytic in the open unit disc E. Then f is said to belong to the class $M_{\alpha}$ of alpha-convex functions, if it satisfies the condition ${\Re}\{(1-{{\alpha})}{\frac{zf^{\prime}(z)}{f(z)}}+{{\alpha}}{\frac{(zf^{\prime}(z))^{\prime})}{f^{\prime}(z)}}\}$ > 0, ($z{\in}E$). In this paper, we introduce and study q-analogue of the class $M_{\alpha}$ by using concepts of Quantum Analysis. It is shown that the functions in this new class $M(q,{\alpha})$ are q-starlike. A problem related to q-Bernardi operator is also investigated.

• Bulletin of the Korean Mathematical Society
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• v.52 no.6
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• pp.1937-1943
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• 2015

For $1{\leq}{\alpha}<2$, let $\mathcal{F}({\alpha})$ denote the class of locally univalent normalized analytic functions $f(z)=z+{\Sigma}_{n=2}^{\infty}{a_nz^n}$ in the unit disk ${\mathbb{D}}=\{z{\in}{\mathbb{C}}:{\left|z\right|}<1\}$ satisfying the condition $Re\(1+{\frac{zf^{{\prime}{\prime}}(z)}{f^{\prime}(z)}}\)>{\frac{{\alpha}}{2}}-1$. In the present paper, we shall obtain the sharp upper bound for Fekete-$Szeg{\ddot{o}}$ functional $|a_3-{\lambda}a_2^2|$ for the complex parameter ${\lambda}$.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.583-586
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• 2016

단백질과 RNA의 상호작용 데이터가 대량으로 늘어남에 따라, 단백질과 RNA의 결합부위를 예측하는 계산학적인 방법들이 많이 개발되고 있다. 하지만, 많은 계산학적인 방법들은 단백질에서 단백질과 RNA 결합부위를 예측한다는 한계점이 있었다. 본 논문에서는 RNA와 단백질의 서열정보를 모두 사용하여, 단백질과 결합하는 RNA 결합부위를 예측하는 기법과 그 결과를 논한다. WEKA random forest(http://www.cs.waikato.ac.nz/ml/weka/)를 이용하여 예측 모델을 개발하였고, RNA 서열의 서열 프로파일, 서열 composition, 결합 상대방의 단백질의 특성 등을 특정으로 표현하였다. Random forest 기법을 사용한 cross validation의 결과로서 1:1 모델에서 제일 높은 성능인 92.4% sensitivity, 92.0% specificity, 92.2% accuracy를 보였고, independent test에서는 72.5% sensitivity, 90.0% specificity, 2.1% accuracy를 보였다.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.19-22
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• 1997

This paper studies the arousal effects of aroma and warning sound using EDA(Electrodermal Activity:EDA), Aroma stimulus started at Nz value over 1.2. Warning sound was prepared according to the arousal evaluation and control criteria. As a result, the warning sound could be controlled the arousal level in all the mKSS state. Aroma stimulus was able to prevent drowsy more than warning sound in the mKSS 3 state(the first stage of drowsiness). Therefor, aroma stimulus was can be used for arousal control at that state. Futhermore, arousal control was shown to be more effective with presentation of both aroma and warning sounds than each presentation.