575 research outputs found
FlexAuc: Serving Dynamic Demands in a Spectrum Trading Market with Flexible Auction
In secondary spectrum trading markets, auctions are widely used by spectrum
holders (SHs) to redistribute their unused channels to secondary wireless
service providers (WSPs). As sellers, the SHs design proper auction schemes to
stimulate more participants and maximize the revenue from the auction. As
buyers, the WSPs determine the bidding strategies in the auction to better
serve their end users.
In this paper, we consider a three-layered spectrum trading market consisting
of the SH, the WSPs and the end users. We jointly study the strategies of the
three parties. The SH determines the auction scheme and spectrum supplies to
optimize its revenue. The WSPs have flexible bidding strategies in terms of
both demands and valuations considering the strategies of the end users. We
design FlexAuc, a novel auction mechanism for this market to enable dynamic
supplies and demands in the auction. We prove theoretically that FlexAuc not
only maximizes the social welfare but also preserves other nice properties such
as truthfulness and computational tractability.Comment: 11 pages, 7 figures, Preliminary version accepted in INFOCOM 201
Undominated Groves Mechanisms
The family of Groves mechanisms, which includes the well-known VCG mechanism
(also known as the Clarke mechanism), is a family of efficient and
strategy-proof mechanisms. Unfortunately, the Groves mechanisms are generally
not budget balanced. That is, under such mechanisms, payments may flow into or
out of the system of the agents, resulting in deficits or reduced utilities for
the agents. We consider the following problem: within the family of Groves
mechanisms, we want to identify mechanisms that give the agents the highest
utilities, under the constraint that these mechanisms must never incur
deficits.
We adopt a prior-free approach. We introduce two general measures for
comparing mechanisms in prior-free settings. We say that a non-deficit Groves
mechanism {\em individually dominates} another non-deficit Groves mechanism
if for every type profile, every agent's utility under is no less than
that under , and this holds with strict inequality for at least one type
profile and one agent. We say that a non-deficit Groves mechanism {\em
collectively dominates} another non-deficit Groves mechanism if for every
type profile, the agents' total utility under is no less than that under
, and this holds with strict inequality for at least one type profile. The
above definitions induce two partial orders on non-deficit Groves mechanisms.
We study the maximal elements corresponding to these two partial orders, which
we call the {\em individually undominated} mechanisms and the {\em collectively
undominated} mechanisms, respectively.Comment: 34 pages. To appear in Journal of AI Research (JAIR
Designing Coalition-Proof Reverse Auctions over Continuous Goods
This paper investigates reverse auctions that involve continuous values of
different types of goods, general nonconvex constraints, and second stage
costs. We seek to design the payment rules and conditions under which
coalitions of participants cannot influence the auction outcome in order to
obtain higher collective utility. Under the incentive-compatible
Vickrey-Clarke-Groves mechanism, we show that coalition-proof outcomes are
achieved if the submitted bids are convex and the constraint sets are of a
polymatroid-type. These conditions, however, do not capture the complexity of
the general class of reverse auctions under consideration. By relaxing the
property of incentive-compatibility, we investigate further payment rules that
are coalition-proof without any extra conditions on the submitted bids and the
constraint sets. Since calculating the payments directly for these mechanisms
is computationally difficult for auctions involving many participants, we
present two computationally efficient methods. Our results are verified with
several case studies based on electricity market data
Expressiveness and Robustness of First-Price Position Auctions
Since economic mechanisms are often applied to very different instances of
the same problem, it is desirable to identify mechanisms that work well in a
wide range of circumstances. We pursue this goal for a position auction setting
and specifically seek mechanisms that guarantee good outcomes under both
complete and incomplete information. A variant of the generalized first-price
mechanism with multi-dimensional bids turns out to be the only standard
mechanism able to achieve this goal, even when types are one-dimensional. The
fact that expressiveness beyond the type space is both necessary and sufficient
for this kind of robustness provides an interesting counterpoint to previous
work on position auctions that has highlighted the benefits of simplicity. From
a technical perspective our results are interesting because they establish
equilibrium existence for a multi-dimensional bid space, where standard
techniques break down. The structure of the equilibrium bids moreover provides
an intuitive explanation for why first-price payments may be able to support
equilibria in a wider range of circumstances than second-price payments
A Mechanism for Fair Distribution of Resources without Payments
We design a mechanism for Fair and Efficient Distribution of Resources
(FEDoR) in the presence of strategic agents. We consider a multiple-instances,
Bayesian setting, where in each round the preference of an agent over the set
of resources is a private information. We assume that in each of r rounds n
agents are competing for k non-identical indivisible goods, (n > k). In each
round the strategic agents declare how much they value receiving any of the
goods in the specific round. The agent declaring the highest valuation receives
the good with the highest value, the agent with the second highest valuation
receives the second highest valued good, etc. Hence we assume a decision
function that assigns goods to agents based on their valuations. The novelty of
the mechanism is that no payment scheme is required to achieve truthfulness in
a setting with rational/strategic agents. The FEDoR mechanism takes advantage
of the repeated nature of the framework, and through a statistical test is able
to punish the misreporting agents and be fair, truthful, and socially
efficient. FEDoR is fair in the sense that, in expectation over the course of
the rounds, all agents will receive the same good the same amount of times.
FEDoR is an eligible candidate for applications that require fair distribution
of resources over time. For example, equal share of bandwidth for nodes through
the same point of access. But further on, FEDoR can be applied in less trivial
settings like sponsored search, where payment is necessary and can be given in
the form of a flat participation fee. To this extent we perform a comparison
with traditional mechanisms applied to sponsored search, presenting the
advantage of FEDoR
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