Tesis doctoral de Javier Murillo Espinar
In environments where resources are perishable and the allocation of resources is repeated over time with the same set or a very similar set of agents, recurrent auctions come up. A recurrent auction is a sequence of auctions where the result of one auction can influence the following ones. These kinds of auctions have particular problems, however, when the wealth of the agents is unevenly distributed and resources are perishable. The bidder drop problem appears when many bidder agents decide to leave the market (because they are participating in many auctions and they are always losing); this lowering of the demand produces a decrease in the prices and, consequently, the auctioneer gets less profit and the auction could even collapse. The resource waste problem turns up when not all the resources are sold (which could be a solution to the previous problem) and they lose their value because perishable resources cannot be stored for future sales. Finally, the asymmetric balance of negotiation power occurs when the richest agents gain enough power to set the prices and they set it at the minimum price possible, causing the collapse of the market. The revenue of the auctioneer is then being affected by all these problems. in this thesis some fair mechanisms are proposed to deal with these problems, so that the revenue of the auctioneer is improved in the long term. In a recurrent auction a fair solution means that at long term, all participants accomplish their goals in the same degree or in the most equal possible degree, independently of their wealth. Concretely this thesis tackles the recurrent multi-unit auctions (recurrent mua) and recurrent multi-unit combinatorial auctions (recurrent muca). In a mua the auctioneer sells several units of a unique resource and the bidders bid for only a unit while in a muca the auctioneer sells several resources and several units of each resource and bidders can bid for packages of resources and different quantities for each resource. we have experimentally shown how the inclusion of fairness incentives to bidders stay in the auction reducing the effect of the bidder drop problem and reducing the effects of resource waste. We have also experimentally shown how the use of reservation prices can be mixed with priorities in order to obtain mechanisms able to maintain the negotiation power of the auctioneer. However there are some dynamic situations where the fair mechanism needs also a method to avoid that rich bidders obtain the resources at a cheaper price. We have called this mechanism control of fair resources. The combination of these three components: priorities, reservation prices and control of rich bidders bring two of the proposed mechanisms to obtain the best performance under all simulated situations. finally, the possible manipulations performed by bidders and equilibriums reached by the fair mechanisms have been studied concluding that fair mechanisms work well in domains where bidders are honest. However, in other situations bidders can manipulate in some way the priorities and reservation prices obtaining non desirable equilibriums for the auctioneer.
Datos académicos de la tesis doctoral «Egalitarian behaviour in multi unit combinatorial auctions«
- Título de la tesis: Egalitarian behaviour in multi unit combinatorial auctions
- Autor: Javier Murillo Espinar
- Universidad: Girona
- Fecha de lectura de la tesis: 10/11/2010
Dirección y tribunal
- Director de la tesis
- Beatriz López Ibáñez
- Tribunal
- Presidente del tribunal: Juan Antonio Rodriguez aguilar
- sarvapali Ramchurn (vocal)
- Miguel ángel Salido gregorio (vocal)
- Francisco Javier Larrosa bondia (vocal)