• 호남수학학술지
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• 제25권1호
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• pp.83-91
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• 2003

We prove a unique continuation theorem for $C^{\infty}$ functions in pseudoconvex domains in ${\mathbb{C}}^{n}$. More specifically, we show that if ${\Omega}$ is a pseudoconvex domain in ${\mathbb{C}}^n$, if f is in $C^{\infty}({\Omega})$ such that for all multi-indexes ${\alpha},{\beta}$ with ${\mid}{\beta}{\mid}{\geq}1$ and for any positive integer k, there exists a positive constant $C_{{\alpha},{\beta},{\kappa}}$ such that $$|{\frac{{\partial}^{{\mid}{\alpha}{\mid}+{\mid}{\beta}{\mid}}f}{{\partial}z^{\alpha}{\partial}{\bar{z}}^{\beta}}{\mid}{\leq}C_{{\alpha},{\beta},{\kappa}}{\mid}f{\mid}^{\kapp}}\;in\;{\Omega}$$, and if there exists $z_0{\in}{\Omega}$ such that f vanishes to infinite order at $z_0$, then f is identically zero. We also have a sharp result for the case of strongly pseudoconvex domains.

• 충청수학회지
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• 제22권3호
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• pp.519-524
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• 2009

In multivariate analysis, the inversion formula of the Stieltjes transform is used to find the density of a spectral distribution of random matrices of sample covariance type. Let $B_{n}\;=\;\frac{1}{n}Y_{m}^{T}T_{m}Y_{m}$ where $Ym\;=\;[Y_{ij}]_{m{\times}n}$ is with independent, identically distributed entries and $T_m$ is an $m{\times}m$ symmetric nonnegative definite random matrix independent of the $Y_{ij}{^{\prime}}s$. In the present paper, using the inversion formula of the Stieltjes transform, we will find the density function of the limiting distribution of $B_n$ away from zero.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.877-882
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• 2005

The definition of multi-coupled operation is that coupled two trainsets is able to be operated one trainset identically. That is to say, the one driver, coupled two trainsets can operate the traction and braking system, control vehicle doors, phanto-graph, HVAC and passenger room lighting system etc, such as one trainset controlling. This study will provide high speed train design engineer with introducing multi-coupled operation system electrically and presentation automatic complex coupler mechanism, and then this paper will be applied to design next generation high speed train system such as Jun-la/Ho-nam line

• 산업경영시스템학회지
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• 제15권26호
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• pp.189-199
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• 1992

Standard acceptance sampling plans models the production process as a sequence of independent identically distributed Beruoulli random variables. However, the quality of items sampled sequentially from an ongoing production process often exhibits statistical dependency that is not accounted for in standard acceptance sampling plans. In this paper, a dependent production process is modelled as an ARMA process and as a two-state Markov chain. A simulation study of each is performed. A comparison of the probability of acceptance is done for the simulation method and for the approximation method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권1호
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• pp.260-279
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• 2015

In this paper, we investigate physical layer security for multiple decode-and-forward (DF) relaying underlay cognitive radio networks (CRNs) with fixed transmit power at the secondary network against passive eavesdropping attacks. We propose a simple relay selection scheme to improve wireless transmission security based on the instantaneous channel information of all legitimate users and the statistical information about the eavesdropper channels. The closed-form expressions of the probability of non-zero secrecy capacity and the secrecy outage probability (SOP) are derived over independent and non-identically distributed Rayleigh fading environments. Furthermore, we conduct the asymptotic analysis to evaluate the secrecy diversity order performance and prove that full diversity is achieved by using the proposed relay selection. Finally, numerical results are presented to verify the theoretical analysis and depict that primary interference constrain has a significant impact on the secure performance and a proper transmit power for the second transmitters is preferred to be energy-efficient and improve the secure performance.

• Communications for Statistical Applications and Methods
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• 제16권5호
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• pp.841-849
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• 2009

Let {$X_n$, n ${\ge}$ 1} be a negatively associated sequence of identically distributed random variables with mean zeros and positive finite variances. Set $S_n$ = ${\Sigma}^n_{i=1}\;X_i$. Suppose that 0 < ${\sigma}^2=EX^2_1+2{\Sigma}^{\infty}_{i=2}\;Cov(X_1,\;X_i)$ < ${\infty}$. We prove that, if $EX^2_1(log^+{\mid}X_1{\mid})^{\delta}$ < ${\infty}$ for any 0< ${\delta}{\le}1$, then $\lim_{{\epsilon}\downarrow0}{\epsilon}^{2{\delta}}\sum_{{n=2}}^{\infty}\frac{(logn)^{\delta-1}}{n^2}ES^2_nI({\mid}S_n{\mid}\geq{\epsilon}{\sigma}\sqrt{nlogn}=\frac{E{\mid}N{\mid}^{2\delta+2}}{\delta}$, where N is the standard normal random variable. We also prove that if $S_n$ is replaced by $M_n=max_{1{\le}k{\le}n}{\mid}S_k{\mid}$ then the precise rate still holds. Some results in Fu and Zhang (2007) are improved to the complete moment case.

• 말소리와 음성과학
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• 제6권4호
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• pp.127-132
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• 2014

This paper describes a robust speech recognition technique by reconstructing spectral components mismatched with a training environment. Although the cluster-based reconstruction method can compensate the unreliable components from reliable components in the same spectral vector by assuming an independent, identically distributed Gaussian-mixture process of training spectral vectors, the presented method exploits the temporal dependency of speech to reconstruct the components by introducing a hidden-Markov-model prior which incorporates an internal state transition plausible for an observed spectral vector sequence. The experimental results indicate that the described method can provide temporally consistent reconstruction and further improve recognition performance on average compared to the conventional method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.249-251
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• 2007

The proposed LDS(Link-status Dependent Scheduling) algorithm in HR-WPAN up to now aims at doing only throughput elevation of the whole network, when the crucial DEV(Device) is connected with worst-link relatively, throughput of this DEV becomes aggravation, The proposed the WGS(Worst-case Guaranteed Scheduling) _algorithm in this paper guarantees throughput of the DEV which is connected with worst-link in a certain degree as maintaining throughput of all DEVs identically even if a link-status changes, decreases delay of the whole network more than current LDS algorithm Therefore proposed WGS algorithm in this paper will be useful in case of guaranteeing throughput of a DEV which is connected worst-link in a certain degree in a design of HR-WPAN hereafter.

• 대한수학회논문집
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• 제10권2호
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• pp.439-442
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• 1995

Let ${X_n : n = 1,2,\cdots}$ be a sequence of pairwise independent identically distributed random vectors taking values in a separable Hilbert space H such that $E \Vert X_1 \Vert = \infty$. Let $S_n = X_1 + X_2 + \cdots + X_n$ and for any real $\alpha$ with $0 < \alpha < 1$ define a sequence ${\gamma_n(\alpha)}$ as $\gamma_n(\alpha) = inf {r : P(\Vert S_n \Vert \leq r) \geq \alpha}$. Then $$ lim_{n \to \infty} sup \Vert S_n \Vert/\gamma_n(\alpha) = \infty $$ holds. This is a generalization of Vvedenskaya[2].

• 대한수학회지
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• 제45권2호
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• pp.355-365
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• 2008

Let ${Y_i;-\infty<i<\infty}$ be a doubly infinite sequence of identically distributed and $\phi$-mixing random variables with zero means and finite variances and ${a_i;-\infty<i<\infty}$ an absolutely summable sequence of real numbers. In this paper, we prove the complete moment convergence of ${{\sum}_{k=1}^{n}\;{\sum}_{i=-\infty}^{\infty}\;a_{i+k}Y_i/n^{1/p};n\geq1}$ under some suitable conditions.