In many natural situations, one observes a local system with many competing species that is coupled by weak immigration to a regional species pool. The dynamics of such a system is dominated by its stable and uninvadable (SU) states. When the competition matrix is random, the number of SUs depends on the average value and variance of its entries. Here we consider the problem in the limit of wea...

To understand the multiple relations between developers and projects on GitHub as a whole, we model them as a multilayer bipartite network and analyze the degree distributions, the nearest neighbors’ degree distributions and their correlations with degree, and the collaborative similarity distributions and their correlations with degree. Our results show that all degree distributions have a pow...

Efficient, Reliable, and Secure Content Delivery

Recent years have witnessed significant efforts in deriving and embedding semantic information in content for improved content retrieval, adaptation, and distribution. Relatively little work considers leveraging this semantic information in the infrastructure to better serve the needs of clients and achieve better cost-effectiveness of infrastructure resources. In this paper, we identify semant...

In contrast to the classical goal of group testing, we consider the problem of finding m defective elements out of D (m ≤ D). We analyze two different test functions. We give adaptive strategies and present lower bounds for the number of tests and show that our strategy is optimal for m = 1. DOI: 10.1134/S0032946012020068

The aim of this paper is to apply inflated geometric distribution to study the distribution of rural out-migrants from a household. The inflated geometric distribution is found to be a reasonable approximation to describe this distribution. The estimated value of risk parameter α was found to be 0.7004229. Findings may help planners and policy makers for designing more effective and equitable r...

Re-using e-learning content is a solution often proposed against the high-cost of the creation high-quality e-learning material, a solution with a neglectable price. In this paper we propose a content distribution model that addresses the long term evolution of content pieces whose quality raises along with re-uses. A realization of this model is presented for the ActiveMath learning environmen...

In this paper we consider the Weibull distribution as a model for technical efficiency. The distribution has a shape and scale parameter like the gamma distribution and can be a reasonable competitor in practice. The techniques are illustrated using artificial data as well as a panel of Spanish dairy farms.

for all test functions f , where y′ = y/|y| ∈ Sn−1. We denote SIΩ,h( f ) by SIΩ( f ) if h= 1. The operator SIΩ was first studied by Calderón and Zygmund in their well-known papers (see [1, 2]). They proved that SIΩ is Lp(Rn) bounded, 1 < p < ∞, provided that Ω ∈ LLog+L(Sn−1) satisfying (1.1). They also showed that the space LLog+L(Sn−1) cannot be replaced by any Orlicz space Lφ(Sn−1) with a mon...