Efficient and strategy-proof mechanisms for general concave user utilities

This paper introduces a novel methodology for designing efficient and strategy-proof direct mechanisms for a class of problems, where the user types are represented by smooth, concave, and increasing utility functions. Such mechanisms facilitate distributed control and allocation of resources. Hence, they are applicable to diverse problems ranging from those in communication networks to energy management. A three-step mechanism design process is presented for deriving the resource allocation and pricing functionals based on user bids in an auction setting. The properties of the resulting class of mechanisms are formally analysed using strategic (noncooperative) games. Although these mechanisms belong to the Groves class, they differ from the Vickrey-Clarke-Groves (VCG) mechanisms. The developed design process is illustrated with analytically tractable examples, which are motivated by network control problems and use scalar-parameterised logarithmic utility functions. It is shown that the resulting schemes are both efficient and truth-revealing (strategy proof) as expected

Incentive-driven QoS in peer-to-peer overlays

A well known problem in peer-to-peer overlays is that no single entity has control over the software, hardware and configuration of peers. Thus, each peer can selfishly adapt its behaviour to maximise its benefit from the overlay. This thesis is concerned with the modelling and design of incentive mechanisms for QoS-overlays: resource allocation protocols that provide strategic peers with participation incentives, while at the same time optimising the performance of the peer-to-peer distribution overlay. The contributions of this thesis are as follows. First, we present PledgeRoute, a novel contribution accounting system that can be used, along with a set of reciprocity policies, as an incentive mechanism to encourage peers to contribute resources even when users are not actively consuming overlay services. This mechanism uses a decentralised credit network, is resilient to sybil attacks, and allows peers to achieve time and space deferred contribution reciprocity. Then, we present a novel, QoS-aware resource allocation model based on Vickrey auctions that uses PledgeRoute as a substrate. It acts as an incentive mechanism by providing efficient overlay construction, while at the same time allocating increasing service quality to those peers that contribute more to the network. The model is then applied to lagsensitive chunk swarming, and some of its properties are explored for different peer delay distributions. When considering QoS overlays deployed over the best-effort Internet, the quality received by a client cannot be adjudicated completely to either its serving peer or the intervening network between them. By drawing parallels between this situation and well-known hidden action situations in microeconomics, we propose a novel scheme to ensure adherence to advertised QoS levels. We then apply it to delay-sensitive chunk distribution overlays and present the optimal contract payments required, along with a method for QoS contract enforcement through reciprocative strategies. We also present a probabilistic model for application-layer delay as a function of the prevailing network conditions. Finally, we address the incentives of managed overlays, and the prediction of their behaviour. We propose two novel models of multihoming managed overlay incentives in which overlays can freely allocate their traffic flows between different ISPs. One is obtained by optimising an overlay utility function with desired properties, while the other is designed for data-driven least-squares fitting of the cross elasticity of demand. This last model is then used to solve for ISP profit maximisation