نتایج جستجو برای: lognormal distribution

تعداد نتایج: 609413  

Journal: :Neotropical entomology 2009
Juliana Simião-Ferreira Paulo DeMarco Gustavo R Mazão Adriana R Carvalho

In this study we determined the taxonomic diversity of larval Chironomidae upstream and downstream to discharges of the sewage treatment plant (STP) from Agro-industrial District of Anápolis, State of Goiás, Brazil. Additionally, we evaluated the use of the lognormal distribution as a measure of biotic integrity of this system. The Chironomidae communities were sampled in three sites, upstream ...

2014
Thomas L. Toulias Christos P. Kitsos Mohammad Fraiwan Al-Saleh

This paper introduces, investigates, and discusses the γ-order generalized lognormal distribution (γ-GLD). Under certain values of the extra shape parameter γ, the usual lognormal, log-Laplace, and log-uniform distribution, are obtained, as well as the degenerate Dirac distribution.The shape of all themembers of the γ-GLD family is extensively discussed.The cumulative distribution function is e...

2005
Jingxian Wu Neelesh Mehta Jin Zhang Neelesh B. Mehta

A simple and novel method is presented to approximate the distribution of the sum of independent, but not necessarily identical, lognormal random variables, by the lognormal distribution. It is shown that matching a short GaussHermite approximation of the moment generating function of the lognormal sum with that of the lognormal distribution leads to an accurate lognormal sum approximation. The...

2014
Søren Asmussen Jens Ledet Jensen Leonardo Rojas-Nandayapa

In this review, we will consider two closely related problems associated with the lognormal distribution: The approximation of the distribution of a lognormal sum (in the whole support) and the approximation of the Laplace transform of a lognormal distribution. The Laplace transform of the lognormal distribution can be employed to approximate the distribution of the lognormal sum via transform ...

Journal: :Microelectronics Reliability 1994

Journal: :J. Informetrics 2016
Mike Thelwall

Although statistical models fit many citation data sets reasonably well with the best fitting models being the hooked power law and discretised lognormal distribution, the fits are rarely close. One possible reason is that there might be more uncited articles than would be predicted by any model if some articles are inherently uncitable. Using data from 23 different Scopus categories, this arti...

Journal: :CoRR 2016
Norbert Blenn Piet Van Mieghem

In this paper, we are analyzing the interactivity time, defined as the duration between two consecutive tasks such as sending emails, collecting friends and followers and writing comments in online social networks (OSNs). The distributions of these times are heavy tailed and often described by a power-law distribution. However, powerlaw distributions usually only fit the heavy tail of empirical...

M. R. Bhosale R. V. Latpate

Market demand of the  perishable bakery  products are volatile. Hence, demand of such items are random variable. The most appealing demand distribution of such items is lognormal demand distribution. Using historical data, the parameters of lognormal distribution are obtained. But, there is a problem of overestimation or underestimation of the parameters. Fuzzy triangular numbers are used to ov...

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