Assume that ? and ? are two independent random variables with distribution functions F? F?, respectively. The of a variable ??, denoted by F??F?, is called the product-convolution F?. It proved F??F? generalized subexponential if belongs to class distributions nonnegative not degenerated at zero.

In this paper, we propose a generic method to construct Hierarchical Identity-Based Signcryption scheme. Using this method, a Hierarchical Identity-Based Signcryption scheme can be converted from any Hierarchical Identity-Based Encryption scheme. Then, we give a concrete instantiation, which is the first constant-size fully secure hierarchical identity-based signcryption scheme in the standard ...

We propose a class of double hierarchical generalized linear models in which random effects can be specified for both the mean and dispersion. Heteroscedasticity between clusters can be modelled by introducing random effects in the dispersion model, as is heterogeneity between clusters in the mean model.This class will, among other things, enable models with heavy-tailed distributions to be exp...