• Title/Summary/Keyword: ${\alpha}$-parameter

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The uncertainty of age measurements in Globular Clusters by the variations of the 2$^{nd}$ parameter candidates

  • Han, Sang-Il;Lee, Young-Wook
    • Bulletin of the Korean Space Science Society
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    • 2004.04a
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    • pp.89-89
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    • 2004
  • It is believed that age controls horizontal-branch (HB) morphology of Globular Clusters besides metallicity (first parameter). However, other second parameter candidates, such as He abundance and alpha elements enhancement, could also affect HB morphology. These effects may influence to the age measurements from the main-sequence turnoff (MSTO) as well. We will measure the variations of age caused by each second parameter candidate at HB and MSTO respectively, using the well known second parameter pair M3 and Ml3. (omitted)

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Comparison of different estimators of P(Y

  • Hassan, Marwa KH.
    • International Journal of Reliability and Applications
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    • v.18 no.2
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    • pp.83-98
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    • 2017
  • Stress-strength reliability problems arise frequently in applied statistics and related fields. In the context of reliability, the stress-strength model describes the life of a component, which has a random strength X and is subjected to random stress Y. The component fails at the instant that the stress applied to it exceeds the strength and the component will function satisfactorily whenever X > Y. The problem of estimation the reliability parameter in a stress-strength model R = P[Y < X], when X and Y are two independent two-parameter Lindley random variables is considered in this paper. The maximum likelihood estimator (MLE) and Bayes estimator of R are obtained. Also, different confidence intervals of R are obtained. Simulation study is performed to compare the different proposed estimation methods. Example in real data is used as practical application of the proposed procedure.

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AN UNFOLDING OF DEGENERATE EQUILIBRIA WITH LINEAR PART $\chi$'v= y, y' = 0

  • Han, Gil-Jun
    • The Pure and Applied Mathematics
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    • v.4 no.1
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    • pp.61-69
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    • 1997
  • In this paper, we study the dynamics of a two-parameter unfolding system $\chi$' = y, y' = $\beta$y+$\alpha$f($\chi\alpha\pm\chiy$+yg($\chi$), where f($\chi$,$\alpha$) is a second order polynomial in $\chi$ and g($\chi$) is strictly nonlinear in $\chi$. We show that the higher order term yg($\chi$) in the system does not change qulitative structure of the Hopf bifurcations near the fixed points for small $\alpha$ and $\beta$ if the nontrivial fixed point approaches to the origin as $\alpha$ approaches zero.

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A NOTE ON THE OPERATOR EQUATION $\alpha+\alpha^{-1}$=$\beta+\beta^{-1}$

  • Thaheem, A.B.
    • Bulletin of the Korean Mathematical Society
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    • v.23 no.2
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    • pp.167-170
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    • 1986
  • Let M be a von Neumann algebra and .alpha., .betha. be *-automorphisms of M satisfying the operator equation .alpha.+.alpha.$^{-1}$ =.betha.+.betha.$^{-1}$ This operator equation has been extensively studied and many important decomposition theorems have been obtained by several authors (for instance see [4], [5], [2], [1]). Originally, this operator equation arose in the paper of Van Daele on the new approach of the Tomita-Takesaki theory in the case of modular operators ([7]). In the case of one-parameter automorphism groups, this equation has produced a bounded and completely positive map which can play a role similar to the infinitesimal generator (for details see [6] and [1]). A recent and one of the most important applications of this equation has been in developing an anglogue of the Tomita-Takesaki theory for Jordan algebras by Haagerup [3]. One general result of this theory is the following.

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Image Analysis using Transform domain-based Human Visual Parameter (변환영역 기반의 시각특성 파라미터를 이용한 영상 분석)

  • Kim, Yoon-Ho
    • Journal of Advanced Navigation Technology
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    • v.12 no.4
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    • pp.378-383
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    • 2008
  • This paper presents a method of image analysis based on discrete cosine transform (DCT) and fuzzy inference(Fl). It concentrated not only on the design of fuzzy inference algorithm but also on incorporating human visual parameter(HVP) into transform coefficients. In the first, HVP such as entropy, texture degree are calculated from the coefficients matrix of DCT. Secondly, using these parameters, fuzzy input variables are generated. Mamdani's operator as well as ${\alpha}$-cut function are involved to simulate the proposed approach, and consequently, experimental results are presented to testify the performance and applicability of the proposed scheme.

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Goodness-of-Fit Test Based on Smoothing Parameter Selection Criteria (평활(平滑) 모수(母數) 선택(選擇)에 기준(基準)한 적합도(適合度) 검정(檢定))

  • Kim, Jong-Tae
    • Journal of the Korean Data and Information Science Society
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    • v.4
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    • pp.137-146
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    • 1993
  • The Proposed goodness-of-fit test Statistic $\hat{\lambda}_{\alpha}$ derived from the test Statistc in Kim (1992) is itself a smoothing parameter which is selected to minimize an estimated MISE for a truncated series estimator, $d_{\hat{\lambda}{n}}$, of the comparison density function. Therefore, this test statistic leads immediately to a point estimate of the density function in the event that $H_{0}$ is ejected. The limiting distribution of $\hat{\lambda}_{\alpha}$ was obtained under the null hypothesis. It is also shown that this test is consistent against fixed alternatives.

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k-OUT-OF-n-SYSTEM WITH REPAIR : T-POLICY

  • Krishnamoorthy, A.;Rekha, A.
    • Journal of applied mathematics & informatics
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    • v.8 no.1
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    • pp.199-212
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    • 2001
  • We consider a k-out-of-n system with repair under T-policy. Life time of each component is exponentially distributed with parameter $\lambda$. Server is called to the system after the elapse of T time units since his departure after completion of repair of all failed units in the previous cycle or until accumulation of n-k failed units, whichever occurs first. Service time is assumed to be exponential with rate ${\mu}$. T is also exponentially distributed with parameter ${\alpha}$. System state probabilities in finite time and long run are derived for (i) cold (ii) warm (iii) hot systems. Several characteristics of these systems are obtained. A control problem is also investigated and numerical illustrations are provided. It is proved that the expected profit to the system is concave in ${\alpha}$ and hence global maximum exists.

MULTIGRID METHOD FOR TOTAL VARIATION IMAGE DENOISING

  • HAN, MUN S.;LEE, JUN S.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.6 no.2
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    • pp.9-24
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    • 2002
  • Total Variation(TV) regularization method is effective for reconstructing "blocky", discontinuous images from contaminated image with noise. But TV is represented by highly nonlinear integro-differential equation that is hard to solve. There have been much effort to obtain stable and fast methods. C. Vogel introduced "the Fixed Point Lagged Diffusivity Iteration", which solves the nonlinear equation by linearizing. In this paper, we apply multigrid(MG) method for cell centered finite difference (CCFD) to solve system arise at each step of this fixed point iteration. In numerical simulation, we test various images varying noises and regularization parameter $\alpha$ and smoothness $\beta$ which appear in TV method. Numerical tests show that the parameter ${\beta}$ does not affect the solution if it is sufficiently small. We compute optimal $\alpha$ that minimizes the error with respect to $L^2$ norm and $H^1$ norm and compare reconstructed images.

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A Characteristic Estimation of Current fed Push Pull Type High Frequency Resonant DC-DC Converter with Active Clamp Circuits (능동클램프회로를 갖는 전류공급 Push-Pull형 고주파공진 DC-DC 컨버터의 특성평가)

  • 오경섭;남승식;김동희
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.8
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    • pp.517-524
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    • 2004
  • In this paper, a novel zero-voltage-switching(ZVS) resonant DC-DC converter is proposed. It is composed of two symmetrical active-clamped circuits, the converter can be achieve ZVS in each switches. Also, active clamp capacitor ratios($\alpha$) of proposed circuit can be reduce a peak stress of switching voltage for each main switch. Simulation results using Pspice 9.2 ver and $C^{++}$ characteristic analysis show a provement for the validity of theoretical analysis. The analysis of the proposed Current-Fed Push Pull type DC-DC converter is generally described by using normalized parameter, and achieved an evaluated characteristic values which is needed to design a circuit. We confirm a rightfulness theoretical analysis by comparing a theoretical values and experimental values obtained from experiment using MOSFET as switching devices.

Sequential confidence intervals for the mean with $\beta$-protection in a certain parameter space

  • Kim, Sung-Lai
    • Journal of the Korean Statistical Society
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    • v.19 no.2
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    • pp.113-121
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    • 1990
  • Let ${X_n : n=1,2,\cdots}$ be iid random variables with distribution $P_{\theta}, \theta \in H$ where $H$ is some abstract parameter space. We consider a sequential confidence interval I for the mean $\mu = \mu(\theta)$ of $P_{\theta}$ satisfying $P_{\theta}(\mu \in I) \geq 1-\alpha$ and $P_{\theta}(\mu-\delta(\mu) \in I) \leq \beta$ for all $\theta \in H$ for any given an imprecision real valued function $\delta(\mu) > 0$ and error probabilities $0 < \alpha, \beta < 1$. A one-sided sequential confidence interval is constructed under some restriction of the family {P_{\theta} : \theta \in H}$ and the imprecision function $\delta$. This is extended to the two-sided cases.

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