Many distributions have been used as lifetime models. In this article, we propose a new threeparameter Weibull–Pareto distribution, which can produce the most important hazard rate shapes, namely, constant, increasing, decreasing, bathtub, and upsidedown bathtub. Various structural properties of the new distribution are derived including explicit expressions for the moments and incomplete momen...

In this paper, we propose an opportunistic channel access scheme based on weighted residual entropy function in cognitive radio networks. This central decision scheme significantly improves spectrum utilization compared with random and first opportunistic spectrum access schemes. Particularly, in this mechanism, appropriate spectrum opportunity will be selected based on the usefulness of idle c...

The clustering Algorithm is a kind of key technique used to reduce energy consumption. It can increase the scalability and lifetime of the network. Energy-efficient clustering protocols should be designed for the characteristic of heterogeneous wireless sensor networks. We propose and evaluate a new distributed energy-efficient clustering scheme for heterogeneous wireless sensor networks, which...