On an Extension of the Exponentiated Weibull Distribution

In this article, the exponentiated Weibull distribution is extended by the Marshall-Olkin family. Our new four-parameter family has a hazard rate function with various desired shapes depending on the choice of its parameters and, thus, it is very flexible in data modeling. It also contains two mixed distributions with applications to series and parallel systems in reliability and also contains several previously known lifetime distributions. We shall study some basic distributional properties of the new distribution. Some closed forms are derived for its moment generating function and moments as well as moments of its order statistics. The model parameters are estimated by the maximum likelihood method. The stress–strength parameter and its estimation are also investigated. Finally, an application of the new model is illustrated using two real datasets.     

Generalized linear failure rate power series distribution

Abstract

In this article, we introduce a new class of lifetime distributions. This new class includes several previously known distributions such as those of Chahkandi and Ganjali (2009 Chahkandi, M., Ganjali, M. (2009). On some lifetime distributions with decreasing failure rate. Computat. Statist. Data Anal. 53:4433–4440.[Crossref], [Web of Science ®] , [Google Scholar]), Mahmoudi and Jafari (2012 Mahmoudi, E., Jafari, A.A. (2012). Generalized exponential power series distributions. Comput. Statist. Data Anal. 56(12):4047–4066.[Crossref], [Web of Science ®] , [Google Scholar]), and Nadarajah et al. (2012 Nadarajah, S., Shahsanaei, F., Rezaei, S. (2012). A new four-parameter lifetime distribution. J. Statist. Computat. Simul.. ifirst, 1–16. [Google Scholar]). This new class of four-parameter distributions allows for flexible failure rate behavior. Indeed, the failure rate function here can be increasing, decreasing, bathtub-shaped or upside-down bathtub-shaped. Several distributional properties of the new class including moments, quantiles and order statistics are studied. An EM algorithm for computing the estimates of the parameters involved is proposed and some maximum entropy characterizations are discussed. Finally, to show the flexibility and potential of the new class of distributions, applications to two real data sets are provided.     

复合词造词材料的语素化问题

复合词的造词法可以将语言系统内不同层级的成分整合在一起.在词义完整性的制约下,这些异质的材料只有取得语素层级的地位时,才能完成造词任务.本文以复合造词这一动态过程为关注点,认为复合造词材料在成词的过程中,有必要引入一个"语素化"的概念.     

The Correlated Bivariate Noncentral F Distribution and Its Application

This article proposes the singly and doubly correlated bivariate noncentral F (BNCF) distributions. The probability density function (pdf) and the cumulative distribution function (cdf) of the distributions are derived for arbitrary values of the parameters. The pdf and cdf of the distributions for different arbitrary values of the parameters are computed, and their graphs are plotted by writing and implementing new R codes. An application of the correlated BNCF distribution is illustrated in the computations of the power function of the pre-test test for the multivariate simple regression model (MSRM).     

Exploring public relations challenges in compounding crises: The pariah effect of toxic trailers

This study examined the distinct exigency of a compounding crisis, a crisis that occurs in close succession to another (potentially unrelated) crisis before an organization has had the opportunity to rebuild legitimacy. Specifically, we identified the public relations challenges faced by the US Federal Emergency Management Agency during the formaldehyde travel trailer crisis and examined how the Hurricane Katrina crisis encumbered the agency’s response efforts. We offer a theoretical frame for understanding the public relations challenges inherent in compounding crises and propose that, in a compounding crisis, organizational legitimacy and social capital decrease while stakeholder risk perceptions and attribution of crisis responsibility increase. A new phenomenon termed the pariah effect is offered to explain when an organization experiencing a compounding crisis is ostracized by other organizations that could assist with the crisis response to avoid negative spillover effects that could result from associating with the offending organization. This study also demonstrates how attribution of responsibility in a compounding crisis can create an exigency in which an organization must take actions beyond the scope and original mission of the organization.     

组合核RVM在CPI预测中的应用研究

针对传统预测模型训练时间长、误差大的缺陷,提出高可靠的组合核相关向量机模型用于CPI预测。构建组合核相关向量机预测模型,根据我国1987年1月至2015年2月的CPI 月度数据,得到CPI的回归预测曲线,再与支持向量机和单核相关向量机进行对比。仿真模拟表明：组合核相关向量机预测模型预测CPI的平均误差可控制在1％以内,运行时间为1．35 s,预测结果良好。     

On compounded geometric distributions and their applications

Here, we introduce two-parameter compounded geometric distributions with monotone failure rates. These distributions are derived by compounding geometric distribution and zero-truncated Poisson distribution. Some statistical and reliability properties of the distributions are investigated. Parameters of the proposed distributions are estimated by the maximum likelihood method as well as through the minimum distance method of estimation. Performance of the estimates by both the methods of estimation is compared based on Monte Carlo simulations. An illustration with Air Crash casualties demonstrates that the distributions can be considered as a suitable model under several real situations.     

The Marshall-Olkin Fréchet Distribution

We introduce a new distribution, namely Marshall–Olkin Fréchet distribution. The probability density and hazard rate functions are derived and their shape properties are considered. Expressions for the nth moments are given. Various results with respect to quantiles, Rényi entropy and order statistics are obtained. The unknown parameters of the new distribution are estimated using the maximum likelihood estimation method adopting three different iterative procedures. The model is applied on a real data set on survival times.

[Supplementary materials are available for this article. Go to the publisher's online edition of Communications in Statistics—Theory and Methods for the following free supplemental resource: A file that will allow the random variables from MOF distribution to be generated.]