This paper uses Chinese urban data to investigate two important issues regarding city size distribution: the nature in which cities of different size grow relative to each other, and which distribution is the best approximation of city size distribution. First, we examine how cities of different sizes grow relative to each other. While most empirical literatures suggest that relative size and r...

Environmental monitoring and classification of rivers in the northern hemisphere is frequently hampered by lack of infrastructure in the scarcely populated areas of the north. Carefully designed economical methods are important. Analysis of 15 constituents in 14 rivers in Iceland show that monthly samples for a period of 1 year are sufficient for 5 classification provided that the correct stati...

The single particle phase function and the linear polarization for large stochastically deformed spheres have been calculated by Monte Carlo simulation using the geometrical optics approximation. The radius vector of a particle is assumed to obey a bivariate lognormal distribution with three free parameters: mean radius, its standard deviation and the coherence length of the autocorrelation f...

On the basis of the analysis of random pulse signal, the mathematical model of the two-parameter random signal is established. Based on which, it is found that the random signal has a non-integer dimension fractal characteristics, and the fractal dimension is the ratio of the count distribution and the number of discrete degree ln σ . Besides, the mass distribution of the particle group is also...

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...

The MareNostrum Universe is one of the largest cosmological SPH simulation done so far. It consists of 1024 dark and 1024 gas particles in a box of 500 h Mpc on a side. Here we study the shapes and spins of the dark matter and gas components of the 10,000 most massive objects extracted from the simulation as well as the gas fraction in those objects. We find that the shapes of objects tend to b...

The effect of the microstructure on the electromigration failure development is analyzed. We investigate the influence of the statistical distribution of copper grain sizes on the electromigration time to failure distribution. Also, the effect of the microstructure on the formation and development of an electromigration-induced void is studied by simulation and the results are compared with exp...

It has been observed that return distributions in general and interest rates in particular exhibit skewness and kurtosis that are inadequately modeled by the lognormal distribution. We have modeled the skewness and kurtosis of the short rate using the g-and-h distribution and Generalized Beta Distribution of the Second Kind (GB2) and compare their performance. The g-and-h distribution is a func...

The problem of assessing occupational exposure using the mean of a lognormal distribution is addressed. The novel concepts of generalized p-values and generalized confidence intervals are applied for testing hypotheses and computing confidence intervals for a lognormal mean. The proposed methods perform well, they are applicable to small sample sizes, and they are easy to implement. Power studi...

1. Frequency of singletons - species represented by single individuals - is anomalously high in most large tropical arthropod surveys (average, 32%). 2. We sampled 5965 adult spiders of 352 species (29% singletons) from 1 ha of lowland tropical moist forest in Guyana. 3. Four common hypotheses (small body size, male-biased sex ratio, cryptic habits, clumped distributions) failed to explain sing...