Reversed hazard function of uncertain lifetime

2017 ◽  
Vol 17 (4) ◽  
pp. 387-400
Author(s):  
Hamed Ahmadzade ◽  
Rong Gao
Author(s):  
Amer Ibrahim Al-Omari ◽  
Khaoula Aidi ◽  
Nacira Seddik-Ameur

In this paper, we developed a new distribution, namely the two parameters Rani distribution (TPRD). Some statistical properties of the proposed distribution are derived including the moments, moment-generating function, reliability function, hazard function, reversed hazard function, odds function, the density function of order statistics, stochastically ordering, and the entropies. The maximum likelihood method is used for model parameters estimation. Following the same approach suggested by Bagdonavicius and Nikulin (2011), modified chi squared goodness-of-fit tests are constructed for right censored data and some tests for right data is considered. An application study is presented to illustrate the ability of the suggested model in fitting aluminum reduction cells sets and the strength data of glass of the aircraft window.


2007 ◽  
Author(s):  
Lara N. Sloboda ◽  
Richard A. Chechile ◽  
Raymond S. Nickerson

2020 ◽  
Vol 70 (4) ◽  
pp. 953-978
Author(s):  
Mustafa Ç. Korkmaz ◽  
G. G. Hamedani

AbstractThis paper proposes a new extended Lindley distribution, which has a more flexible density and hazard rate shapes than the Lindley and Power Lindley distributions, based on the mixture distribution structure in order to model with new distribution characteristics real data phenomena. Its some distributional properties such as the shapes, moments, quantile function, Bonferonni and Lorenz curves, mean deviations and order statistics have been obtained. Characterizations based on two truncated moments, conditional expectation as well as in terms of the hazard function are presented. Different estimation procedures have been employed to estimate the unknown parameters and their performances are compared via Monte Carlo simulations. The flexibility and importance of the proposed model are illustrated by two real data sets.


2009 ◽  
Vol 42 (4) ◽  
pp. 881-910 ◽  
Author(s):  
J. Stephen Ferris ◽  
Marcel-Cristian Voia

Abstract. In this paper we examine the length of political tenure in Canadian federally elected parliamentary governments since 1867. Using annual data on tenure length, we categorize the distribution of governing tenures in terms of a hazard function: the probability that an election will arise in each year, given that an election has not yet been called. Structuring the election call as an optimal stopping rule, we test whether that distribution responds predictably to characteristics of the political and/or economic environment. The results of using the continuous Cox and Gompertz models together with the discrete semi-parametric proportional hazard model suggest that governing parties in Canada do engage in election timing and that the only economic policy measure that is used consistently in conjunction with election timing is fiscal expenditure.Résumé. Dans cet ouvrage, nous examinons la durée d'un régime parlementaire canadien depuis la Confédération de 1867. Nous utilisons des données annuelles et nous représentons la distribution de durée de vie d'un gouvernement par une fonction de hazard, c'est-a-dire, la probabilité qu'une élection soit déclenchée durant une année spécifique étant donné qu'elle ne l'a pas encore été jusqu'à présent. Nous modélisons un déclenchement d'élection par une règle d'arrêt optimal el nous testons si la distribution dépend des caractéristiques de l'environnement politique et économique tel que prédit selon la théorie. Nous résultats basés les modèles de hazard proportionnel continu de type Cox et Gompertz et discret semi-paramétrique révèlent que les partis fédéraux au pouvoir au Canada choisissent le moment opportun pour déclencher une élection. De plus, les dépenses fiscales sont la seule variable de politique économique qui y soit systématiquement relié.


2000 ◽  
Vol 12 (2) ◽  
pp. 367-384 ◽  
Author(s):  
Hans E. Plesser ◽  
Wulfram Gerstner

We analyze the effect of noise in integrate-and-fire neurons driven by time-dependent input and compare the diffusion approximation for the membrane potential to escape noise. It is shown that for time-dependent subthreshold input, diffusive noise can be replaced by escape noise with a hazard function that has a gaussian dependence on the distance between the (noise-free) membrane voltage and threshold. The approximation is improved if we add to the hazard function a probability current proportional to the derivative of the voltage. Stochastic resonance in response to periodic input occurs in both noise models and exhibits similar characteristics.


Author(s):  
Ilaria Ardoino ◽  
Federico Ambrogi ◽  
Chris Bajdik ◽  
Paulo J. Lisboa ◽  
Elia M. Biganzoli ◽  
...  

2010 ◽  
Vol 9 ◽  
pp. CIN.S5460 ◽  
Author(s):  
Tengiz Mdzinarishvili ◽  
Simon Sherman

Mathematical modeling of cancer development is aimed at assessing the risk factors leading to cancer. Aging is a common risk factor for all adult cancers. The risk of getting cancer in aging is presented by a hazard function that can be estimated from the observed incidence rates collected in cancer registries. Recent analyses of the SEER database show that the cancer hazard function initially increases with the age, and then it turns over and falls at the end of the lifetime. Such behavior of the hazard function is poorly modeled by the exponential or compound exponential-linear functions mainly utilized for the modeling. In this work, for mathematical modeling of cancer hazards, we proposed to use the Weibull-like function, derived from the Armitage-Doll multistage concept of carcinogenesis and an assumption that number of clones at age t developed from mutated cells follows the Poisson distribution. This function is characterized by three parameters, two of which ( r and λ) are the conventional parameters of the Weibull probability distribution function, and an additional parameter ( C0) that adjusts the model to the observational data. Biological meanings of these parameters are: r—the number of stages in carcinogenesis, λ—an average number of clones developed from the mutated cells during the first year of carcinogenesis, and C0—a data adjustment parameter that characterizes a fraction of the age-specific population that will get this cancer in their lifetime. To test the validity of the proposed model, the nonlinear regression analysis was performed for the lung cancer (LC) data, collected in the SEER 9 database for white men and women during 1975–2004. Obtained results suggest that: (i) modeling can be improved by the use of another parameter A- the age at the beginning of carcinogenesis; and (ii) in white men and women, the processes of LC carcinogenesis vary by A and C0, while the corresponding values of r and λ are nearly the same. Overall, the proposed Weibull-like model provides an excellent fit of the estimates of the LC hazard function in aging. It is expected that the Weibull-like model can be applicable to fit estimates of hazard functions of other adult cancers as well.


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