Shadow fading causes random fluctuations of the envelope mean at the mobile. The lognormal distribution is widely accepted for this phenomenon. In this paper we argue that, based on theoretical results and measured data, gamma distribution does the job as well. Then we show that by using the gamma distribution and in contrast with the use of the lognormal distribution, we can obtain easy-to-use...

In this paper, the Raindrop Size Distribution (DSD) modeling and analysis are presented. Drop sizes are classified into different rain types, namely: drizzle, widespread, shower and thunderstorm. The gamma and Lognormal distribution models are employed using the method of moments estimator, considering the third, fourth and sixth order moments. The results are compared with the existing raindro...

Finance: In financial mathematics, the most popular model for a stock’s price is the lognormal distribution: if P is the stock price, then log P has a normal distribution. Suppose there are two such stock prices, P1 and P2, and that they both have a lognormal distribution. What is the probability that the sum of the prices will be greater than y? Making the simplifying assumption that the stock...

Although Zipf's law is widespread in natural and social data, one often encounters situations where one or both ends of the ranked data deviate from the power-law function. Previously we proposed the Beta rank function to improve the fitting of data which does not follow a perfect Zipf's law. Here we show that when the two parameters in the Beta rank function have the same value, the Lavalette ...

We propose a new method for calculating a tight approximation to the distribution of the sum of independent lognormal random variables. We use a three-parameter modified-power-lognormal distribution function as the approximating distribution. We use theoretical results from our previous work on the tails of the distribution of the sum of lognormals to match the slope of the modified-power-logno...

We show that according to the GRB internal shock model the pulse duration and the interval between neighboring pulses are correlated and have a similar distribution. We analyze a sample of bright long bursts and find that the pulses duration have a lognormal distribution while the intervals has an excess of long intervals (relative to lognormal distribution). This excess can be explained by the...

Ore-reserve estimations of deposits with low mineral concentrations, such as those of copper, gold and tin, are usually made on the assumption that the grades follow a lognormal distribution. Multiple mineralization or reworking of a deposit may have modified the simple distribution expected — producing an overall distribution of grades which can be adequately described by a mixture of lognorma...

in this paper, we consider admissible estimation of the parameter ?r in the gamma distribution with truncated parameter space under entropy loss function. we obtain the classes of admissible estimators. the result can be applied to estimation of parameters in the normal, lognormal, pareto, generalized gamma, generalized laplace and other distributions.