Free Riding Inhibition Mechanism Based on User Behavior in P2P File-Sharing System

In order to inhibit Free Riding in Peer-toPeer(P2P) file-sharing systems,the Free Riding Inhibition Mechanism Based on User Behavior(IMBUB) is proposed.IMBUB considers the regularity of user behavior and models user behavior by analyzing many definitions and formulas.In IMBUB,Bandwidth Allocated Ratio,Incentive Mechanism Based on User Online Time,Double Reward Mechanism,Incentive Mechanism of Sharing for Permission and Inhibition Mechanism of White-washing Behavior are put forward to inhibit Free Riding and encourage user sharing.A P2P file system BITShare is designed and realized under the conditions of a campus network environment.The test results show that BITShare's Query Hit Ratio has a significant increase from 22% to 99%,and the sharing process in BITShare is very optimistic.Most users opt to use online time to exchange service quality instead of white-washing behavior,and the real white-ishing ratio in BITShare is lower than 1%.We confirm that IMBUB can effectively inhibit Free Riding behavior in P2P file-sharing systems.

A PEER-TO-PEER INCENTIVE SCHEME FOR OVERCOMING FREE RIDING

Free riding has a great influence on the expandability,robustness and availability of Peer-to-Peer(P2P) network.Controlling free riding has become a hot research issue both in academic and industrial communities.An incentive scheme is proposed to overcoming free riding in P2P network in this paper.According to the behavior and function of nodes,the P2P network is abstracted to be a Distributed and Monitoring-based Hierarchical Structure Mechanism(DMHSM) model.A utility function based on several influencing factors is defined to determine the contribution of peers to the whole system.This paper also introduces reputation and permit mechanism into the scheme to guarantee the Quality of Service(QoS) and to reward or punish peers in the network.Finally,the simulation results verify the effectiveness and feasibility of this model.

Service-Cost-Sharing Contract Design for a Dual-Channel Supply Chain with Free Riding

This paper considers a dual channel supply chain,where a manufacturer sells a single product through his/her online channel and a traditional retailer,who provides consumers with pre-sale services.The manufacturer's online channel may free-ride the retailer's pre-sale service,which reduces the retailer's desired effort level,and hence may hurt the manufacturer's and the overall supply chain performance.Under both Manufacturer-and Retailer-Stackelberg settings,we study how the manufacturer designs a service-cost-sharing(SCS for brevity)contract to enhance the retailer's service effort level,and how free riding influences two members'optimal decisions.We design an algorithm for determining the two members’optimal decisions under each setting.The three main findings are found:(i)In the Manufacturer-Stackelberg setting,the SCS contract can enhance the retailer's service effort level and eliminate the negative impact incurred by free riding,but can't in the Retailer-Stackelberg setting,(ii)Under the SCS contract,the smaller the fraction of service cost the retailer is requested to share,the more detrimental to the retailer it will be under certain conditions.That is,the phenomenon called"counter-profit cost-sharing"appears,(iii)Both players like to act as a leader if the price competition between the two channels is not relatively very fierce,otherwise they both like to act as a follower.

The Supply Chain Contract Design under Cap-and-Trade Mechanism with Free Riding

This paper studies the influence of free riding on enterprise product pricing and carbon emissions reduction investment, as well as the contract design to achieve supply chain coordination under the carbon trading mechanism. First, we discuss the situation where carbon emissions reduction investment affects the product price and income. It demonstrates that the optimal investment of the upstream manufacturer increases with the degree of the free riding of the downstream manufacturer. The upstream manufacturer can improve their carbon reduction investment and the whole supply chain achieves Pareto improvement when the investment cost sharing contract is introduced. Nevertheless, under the cost-sharing contract the optimal investment of the decentralized supply chain is still lower than that of the centralized supply chain, and only in some particular cases can the two types of supply chain achieve equal total profits. Then, we preliminarily explore the situation where the product price and income is influenced by carbon emissions reduction investment. The consequences indicate that the optimal investment of the upstream manufacturers in this situation is less than the former one's, and the transfer payment mechanism is able to improve the level of the supply chain overall carbon emissions-reduction. Moreover, compared to the former situation, the effects of free riding of the downstream manufacturer are even more serious. The conclusions can provide some intellectual support for manufacturing enterprises to make reasonable emissions reduction strategies and coordinate the supply chain existing in free riding.

匿名通信系统中自私行为的惩罚机制研究

针对匿名通信系统中成员自私行为带来的“Free-Riding”问题进行了研究,量化地分析了匿名通信系统中的自私成员数量对于系统匿名性及工作效率的影响。结果表明,在系统中存在大量自私成员的情况下,匿名通信系统无法保证其匿名性及效率。基于区分服务思想提出一种针对系统中成员自私行为的惩罚机制。理论分析表明:应用惩罚机制后的匿名系统在仍然保证成员的匿名性的前提下,能够有效降低自私成员的工作效率,从而减少自私行为的发生。