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Peer-to-peer (P2P) networks offer a cost-effective and easily deployable framework for sharing content. However, P2P file-sharing applications face a fundamental problem of unfairness. Pricing is regarded as an effective way to provide incentives to peers to cooperate. In this paper we propose a pricing scheme to achieve reasonable resource allocation in P2P file-sharing networks, and give an interpretation for the utility maximization problem and its sub-problems from an economic point of view. We also deduce the exact expression of optimal resource allocation for each peer, and confirm it with both simulation and optimization software. In order to realize the optimum in a decentralized architecture, we present a novel price-based algorithm and discuss its stability based on Lyapunov stability theory. Simulation results confirm that the proposed algorithm can attain an optimum within reasonable convergence times.

The article determines the variety of dimensions involved in green retailing (GR). It investigates the roles of retailers in greening the value chain through the establishment of preliminary framework grounded in the natural resource-based view of the firm (NRBV). It also discusses the emerging importance of GR in modern retailing industry.

The long-term monitoring of thorium inhaled by workers and assessment of their thorium lung burden has been carried out in China since 1960. Various monitoring methods have been adopted, such as chemical analysis of thorium concentration in urine samples; assessing thorium lung burden by measurement of 212Pb etc. using a whole-body counter; measurement of exhaled thoron using a ZnS detector; or exhaled thoron decay products using an electrostatic collection system. Our experience over more than 20 years has shown that the last named measurement system is the best method for monitoring and assessing the lung burden of thorium (ThO2) inhaled by miners and workers.