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If g and G are the pdf and the cdf of a distribution symmetric around 0 then the pdf 2g(u)G(λ
u) is said to define a skew distribution. In this paper, we provide a mathematical treatment of the skew distributions when
g and G are taken to come from one of Pearson type II, Pearson type VII or the generalized t distribution.
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In this paper, we introduce a new extension of the power Lindley distribution, called the exponentiated generalized power Lindley distribution. Several mathematical properties of the new model such as the shapes of the density and hazard rate functions, the quantile function, moments, mean deviations, Bonferroni and Lorenz curves and order statistics are derived.Moreover, we discuss the parameter estimation of the new distribution using the maximum likelihood and diagonally weighted least squares methods. A simulation study is performed to evaluate the estimators. We use two real data sets to illustrate the applicability of the new model. Empirical findings show that the proposed model provides better fits than some other well-known extensions of Lindley distributions. 相似文献
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Saralees Nadarajah 《Comptes Rendus Mathematique》2005,341(2):129-132
Recent papers by Professor T. Pham-Gia derived distributions of sums, differences, products and ratios of independent beta random variables. In this Note we extend Professor Pham-Gia's results when and are independent random variables distributed according to the confluent and Gauss hypergeometric distributions (which are generalizations of the beta distribution). For each of these distributions, we derive exact expressions for the densities of , , , and . The expressions turn out to involve the hypergeometric functions of one and two variables. To cite this article: S. Nadarajah, C. R. Acad. Sci. Paris, Ser. I 341 (2005). 相似文献
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A. Nadarajah R. Narayanan 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1986,37(2):280-283
A very conservative lower bound for buoyancy driven convection in bounded geometries is obtained. This bound is extremely simple to evaluate and is used to expose inconsistencies in some of the earlier published numerical results.
Zusammenfassung Es wird eine sehr konservative untere Grenze für natürliche Konvektion in begrenzten Gebieten erhalten. Die Grenze läßt sich äußerst einfach berechnen; sie wird benützt um auf inkonsistente Ergebnisse in veröffentlichten numerischen Resultaten hinzuweisen.相似文献
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The known estimation and simulation methods for multivariate t distributions are reviewed. A review of selected applications is also provided. We believe that this review will serve as
an important reference and encourage further research activities in the area. 相似文献
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Saralees Nadarajah 《Mathematical Methods in the Applied Sciences》2008,31(1):35-44
A new Pareto distribution is introduced for pooling knowledge about classical systems. It takes the form of the product of two Pareto probability density functions (pdfs). Various structural properties of this distribution are derived, including its cumulative distribution function (cdf), moments, mean deviation about the mean, mean deviation about the median, entropy, asymptotic distribution of the extreme order statistics, maximum likelihood estimates and the Fisher information matrix. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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We give the cumulative distribution function of $M_n$ , the maximum of a sequence of n observations from a first order moving average. Solutions are first given in terms of repeated integrals and then for the case, where the underlying independent random variables have an absolutely continuous probability density function. When the correlation is positive, $P( M_n \leq x ) \ =\ \sum\limits _{j=1}^{\infty } \beta _{j, x} \ \nu _{j, x}^{n},$ where $\{\nu _{j, x}\}$ are the eigenvalues (singular values) of a Fredholm kernel and $\beta _{j, x}$ are some coefficients determined later. A similar result is given when the correlation is negative. The result is analogous to large deviations expansions for estimates, since the maximum need not be standardized to have a limit. For the continuous case the integral equations for the left and right eigenfunctions are converted to first order linear differential equations. The eigenvalues satisfy an equation of the form $\sum\limits _{i=1}^{\infty } w_i ( \lambda -\theta _i )^{-1}=\lambda -\theta _0$ for certain known weights $\{ w_i\}$ and eigenvalues $\{ \theta _i\}$ of a given matrix. This can be solved by truncating the sum to an increasing number of terms. 相似文献
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Asialoglycoprotein receptor (ASGPR) is one of the recognition motifs on the surface of hepatocytes, which promote their adhesion to extracellular matrix in liver tissue and appropriate artificial surfaces. ASGPR-mediated adhesion is expected to minimize trans-differentiation of hepatocytes in vitro that is generally observed in integrin-mediated adhesion. The aim of the present study is to verify the role of ASGPR in hepatocyte adhesion and proliferation in scaffolds for hepatic tissue engineering. Scanning Electrochemical Microscopy (SECM) is emerging as a suitable non-invasive analytical tool due to its high sensitivity and capability to correlate the morphology and activity of live cells. HepG2 cells and rat primary hepatocytes cultured in Polyvinyl alcohol (PVA)/Gelatin hydrogel scaffolds with and without galactose (a ligand for ASGPR) modification are studied using SECM. Systematic investigation of live cells cultured for different durations in scaffolds of different compositions (9:1 and 8:2 PVA:Gelatin with and without galactose) reveals significant improvement in cell–cell communication and proliferation on galactose incorporated scaffolds, thereby demonstrating the positive influence of ASGPR-mediated adhesion. In this work, we have also developed a methodology to quantify the respiratory activity and intracellular redox activity of live cells cultured in porous tissue engineering scaffolds. Using this methodology, SECM results are compared with routine cell culture assays viz., MTS ((1-Oxyl-2,2,5,5,-tetramethyl-Δ3-pyrroline-3-methyl) Methanethiosulfonate) and Albumin assays to demonstrate the better sensitivity of SECM. In addition, the present study demonstrates SECM as a reliable and sensitive tool to monitor the activity of live cells cultured in scaffolds for tissue engineering, which could be used on a routine basis. 相似文献
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Chemical looping combustion (CLC) is a novel method of carbon capture and sequestration. It facilitates CO2 capture by lower energy penalties compared with other methods in this category. The major challenges encountered in CLC are oxygen carrier, reactor and fuel-type selection. A proper combination of these factors is required for an efficient CLC. There have been several studies with regard to oxygen carriers applicable to these processes: novel oxygen carriers, single perovskites and potential oxygen carriers, double perovskites, have been investigated for their oxygen capture and release properties in a number of studies. Different kinds of reactors have also been proposed for use in CLC processes. This paper presents information on the materials capable of oxygen storage and release and the different kinds of reactors investigated for CLC in different studies. It has been shown that, although there are several oxygen carriers and reactors with the desired function and efficiency for CLC, there remains the need for further improvement and optimisation in both areas. © 2014 Institute of Chemistry, Slovak Academy of Sciences 相似文献