The recent paper by Shao et al (2004) claims to have introduced a new model for frequency analysis referred to as the extended Burr XII distribution. The cumulative distribution function (cdf) and the probability density function (pdf) of this new distribution are specified as: { } { }      λ − − λ − − = c k c x x k x F) / (exp 1) / (1 1) (/ 1 0 if 0 if = ≠ k k (1) and { } { }      λ ...

We study the distribution of volume fluctuations in experiments and numerical simulations concerning equal-sized sphere packings prepared with different techniques. We show that the distribution of the local volumes (Voronoï cells) and also the distributions of the global volumes (whole samples) follow remarkably well a shifted and rescaled Gamma distribution that we name a k-Gamma distribution...

| The probability p(k) that the value of a random variable is far away from the mean (e.g. further than k standard deviations away) is so small that this possibility can be often safely ignored. It is desirable to select k for which the dependence of the probability p(k) on the distribution is the smallest possible. Empirically, this dependence is the smallest for k between 1.5 and 2.5. In this...

The stability of networks is greatly influenced by their degree distributions and in particular by their breadth. Networks with broader degree distributions are usually more robust to random failures but less robust to localized attacks. To better understand the effect of the breadth of the degree distribution we study two models in which the breadth is controlled and compare their robustness a...

a study of physiological responses of different wheat cultivars to saline conditions can lead to an identification of the main mechanisms in salt tolerance. seven bread wheat cultivars differing in salt tolerance with varying ability of sodium accumulation in their different tissues were employed to assess ion distribution and sodium accumulation under saline conditions. ion distribution and na...

In this study, the radial distribution and gravimetric storage capacities of hydrogen on coronene (C24H12) and its Si substituted forms, C24H12, C24-nSinH12 (n= 4-24), have been investigated at 298 K and 0.1 MPa (standard situation) using (N,V,T) Monte Carlo simulation by Lennard-Jones (LJ) 12-6 potential. The results show that the increase of number of silicon substitution doesn’t have any eff...

bamboo-structured carbon nanotubes are grown on co-mo/mcm-41 catalyst in the temperature range of 873-973 k by thermal chemical vapor deposition of acetylene. this study shows that the purified carbon nanotubes have open tips and the metals of the catalyst are not encapsulated. thus, the bamboo-structure seems to grow from the base. pore size distribution of the product is quite narrow and is i...

We examine numerically the distribution function f K (r) of the distance r between opposite polygonal nodes for random polygons with a fixed knot type K. Here we consider some knots such as ∅, 3 1 and 3 1 ♯3 1. In a wide range of r, the shape of f K (r) is well fit to the scaling form [1] derived from the field theory for self-avoiding walks. The fit yields the exponents ν K = 1 2 and γ K = 1, ...

Optimal filtering: The filtering problem involves the estimation of the state vector at time k, given all the measurements up to and including time k, which we denote by z1:k. In a Bayesian setting, this problem can be formalized as the computation of the distribution p(xk|z1:k), which can be done recursively in two steps. In the prediction step, p(xk|z1:k−1) is computed from the filtering dist...