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## Electronic reverse auctions in the federal government

Brown, Whitney E.; Ray, Lana D.
Tipo: Relatório Formato: x, 80 p.: ill.;28 cm.
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Approved for public release; distribution is unlimited; In light of the limited recognition of electronic reverse auctions (e-RA) in the acquisition field, the purpose of this research paper is to further examine the use of e-RAs throughout the federal government and the Department of Defense (DoD). By exploring a multitude of auction types and designs that have been or are currently being used in the private sector, these practices set a basis for researching the auction types being used in the public sector. This paper further explores the regulations guiding the use of e-RAs and investigates the federal government's application of reverse auctions through studies, reports, and interviews with users of e-RAs. Details as to what attributes are prevalent in these e-RAs, what features are best suited for e-RAs, and what benefits have been derived from the use of e-RAs in the federal government are also included. Finally, the researchers found that e-RAs have increased transparency, cost savings, and efficiencies in the acquisition process. Although reverse auctions are being used effectively, the researchers found that there are still opportunities for improvement including incorporating a fully functional best-value tool into e-RA technology and developing more thorough federal guidance on e-RAs as an alternative pricing method.; Outstanding Thesis; Outstanding Thesis

## (Un)bundling Infrastructure Procurement: Evidence from Water Supply and Sewage Projects

Estache, Antonio; Iimi, Atsushi
Fonte: Banco Mundial Publicador: Banco Mundial
Tipo: Publications & Research :: Policy Research Working Paper
ENGLISH
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Competition in public procurement auctions in the water supply and sanitation sector is largely limited. This is partly because of high technical complexity and partly because of auction design flaws. The division of lot contracts is an important policy choice for auctioneers to achieve efficiency. In general, there is a tradeoff between competition in auctions and size of contracts. Larger works could benefit from economies of scale and scope, but large contracts might undermine competition. Using data on public procurement auctions for water and sewage projects in developing countries, this paper shows that bidder entry is crucially endogenous, especially because it is determined by the auctioneer's bundling and unbundling strategy. If water treatment plant and distribution network works are bundled in a single lot package, competition would be significantly reduced, and this adverse entry effect would in turn raise the public procurement costs of infrastructure. There is no evidence of positive scope economies in the bidder cost structure. It is important to account for the underlying cost structure for designing efficient auction mechanisms.

## Designing Auctions for Concessions : Guessing the Right Value to Bid and the Winner's Curse

Klein, Michael
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Viewpoint; Publications & Research
ENGLISH
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Once a government has decided to award a concession by auction, it needs to decide what kind of auction to use. For concessions the standard is a first-price sealed bid auction in which bidders submit sealed envelopes containing their offer and the highest offer determines the price. The bidding may occur in one or two stages. In two-stage bidding the technical parameters of the bids are made comparable in the first stage, and only the main offer on the core bid parameter is submitted in the second. The main offer may relate to a price, a level of subsidy, a payment for net worth, or any other appropriate parameter; the discussion in this Note focuses on price.

## Multi-round auctions for institutional real estate assets : theory and practice

Foley, J. Aidan (James Aidan), 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 135, [45] leaves; 10140619 bytes; 10140427 bytes; application/pdf; application/pdf
ENG
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The theory of auctions has grown dramatically over the last four decades; it offers guidance and insights into the conduct of efficient and optimal auctions in real estate, and other industries. In this thesis an auction process used to sell institutional real estate assets in the US is identified. This auction came into being during the 1990s, and is now in common use. The auction is recorded though surveys with industry representatives and is characterized. Problems with the auction are identified, and solutions are proposed, referencing this auction to the body of auction theory. The auction consists of two rounds of sealed bid submissions, with attrition in the number of competitive bidders. After competitive bidding is complete a preferred bidder is selected, and engages in due diligence, a practice that often uncovers new information and induces renegotiation. Bids are not binding during the bidding process, because the auction is informationally incomplete. Sellers analyze bids based on the perceived quality of the bidder as a contractual partner, as well as the bid's value, complicating the objective selection of the best bidder. The auction is bilaterally incomplete and unstable, potentially influencing efficiency and optimality. Recommendations to improve the process are made. Descriptive statistics are formed and presented of multi-round auctions for institutional real estate assets.; by J. Aidan Foley.; Thesis (S.M.)--Massachusetts Institute of Technology...

## Essays on Applied Microeconomics

Lee, Hoan Soo
Fonte: Harvard University Publicador: Harvard University
Tipo: Thesis or Dissertation
EN_US
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## Virtual Worlds: Fast and Strategyproof Auctions for Dynamic Resource Allocation

Ng, Chaki; Parkes, David C.; Seltzer, Margo I.
Fonte: Association for Computing Machinery Publicador: Association for Computing Machinery
Tipo: Monograph or Book
EN_US
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We consider the problem of designing fast and strategyproof exchanges for dynamic resource allocation problems in distributed systems. The exchange is implemented as a sequence of auctions, with dynamically arriving requests from agents matched with each auction. Each auction is associated with some consignment of the resources from a single seller. We provide a simple Virtual Worlds (VW) construction, that extends a fast and strategyproof mechanism for a single auction to apply to this sequence-of-auctions setting. Rather than match each buyer with a single auction, the VW mechanism allows buyers to be considered for multiple auctions while retaining strategyproofness.; Engineering and Applied Sciences

## Efficient Interdependent Value Combinatorial Auctions with Single Minded Bidders

Robu, Valentin; Parkes, David C.; Ito, Takayuki; Jennings, Nicholas R.
Fonte: AAAI Press Publicador: AAAI Press
Tipo: Conference Paper
EN_US
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We study the problem of designing efficient auctions where bidders have interdependent values; i.e., values that depend on the signals of other agents. We consider a contingent bid model in which agents can explicitly condition the value of their bids on the bids submitted by others. In particular, we adopt a linear contingent bidding model for single minded combinatorial auctions (CAs), in which submitted bids are linear combinations of bids received from others. We extend the existing state of the art, by identifying constraints on the interesting bundles and contingency weights reported by the agents which allow the efficient second priced, fixed point bids auction to be implemented in single minded CAs. Moreover, for domains in which the required single crossing condition fails (which characterizes when efficient, IC auctions are possible), we design a two-stage mechanism in which a subset of agents (''experts") are allocated first, using their reports to allocate the remaining items to the other agents.; Engineering and Applied Sciences

## Combinatorial Auctions with Restricted Complements

Abraham, Ittai; Babaioff, Moshe; Dughmi, Shaddin; Roughgarden, Tim
Tipo: Artigo de Revista Científica
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Complements between goods - where one good takes on added value in the presence of another - have been a thorn in the side of algorithmic mechanism designers. On the one hand, complements are common in the standard motivating applications for combinatorial auctions, like spectrum license auctions. On the other, welfare maximization in the presence of complements is notoriously difficult, and this intractability has stymied theoretical progress in the area. For example, there are no known positive results for combinatorial auctions in which bidder valuations are multi-parameter and non-complement-free, other than the relatively weak results known for general valuations. To make inroads on the problem of combinatorial auction design in the presence of complements, we propose a model for valuations with complements that is parameterized by the "size" of the complements. A valuation in our model is represented succinctly by a weighted hypergraph, where the size of the hyper-edges corresponds to degree of complementarity. Our model permits a variety of computationally efficient queries, and non-trivial welfare-maximization algorithms and mechanisms. We design the following polynomial-time approximation algorithms and truthful mechanisms for welfare maximization with bidders with hypergraph valuations. 1- For bidders whose valuations correspond to subgraphs of a known graph that is planar (or more generally...

## Learning in Auctions: Regret is Hard, Envy is Easy

Tipo: Artigo de Revista Científica
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We show that there are no polynomial-time no-regret learning algorithms for simultaneous second price auctions (SiSPAs), unless $RP\supseteq NP$, even when the bidders are unit-demand. We prove this by establishing a specific result about SiSPAs and a generic statement about online learning. We complement this result by proposing a novel solution concept of learning in auctions, termed "no-envy learning". This notion is founded on Walrasian equilibrium, and we show that it is both efficiently computable and it results in approximate efficiency in SiSPAs, even for bidders from the broad class of XOS valuations (assuming demand oracle access to the valuations) or coverage valuations (even without demand oracles). Our result can be viewed as the first constant approximation for welfare maximization in combinatorial auctions with XOS valuations, where both the designer and the agents are computationally bounded. Our positive result for XOS valuations is based on a new class of Follow-The-Perturbed-Leader algorithms and an analysis framework for general online learning problems, which generalizes the existing framework of (Kalai and Vempala 2005) beyond linear utilities. Our results provide a positive counterpart to recent negative results on adversarial online learning via best-response oracles (Hazan and Korren 2015). We show that these results are of interest even outside auction settings...

## Online learning in repeated auctions

Weed, Jonathan; Perchet, Vianney; Rigollet, Philippe
Tipo: Artigo de Revista Científica
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Motivated by online advertising auctions, we consider repeated Vickrey auctions where goods of unknown value are sold sequentially and bidders only learn (potentially noisy) information about a good's value once it is purchased. We adopt an online learning approach with bandit feedback to model this problem and derive bidding strategies for two models: stochastic and adversarial. In the stochastic model, the observed values of the goods are random variables centered around the true value of the good. In this case, logarithmic regret is achievable when competing against well behaved adversaries. In the adversarial model, the goods need not be identical and we simply compare our performance against that of the best fixed bid in hindsight. We show that sublinear regret is also achievable in this case and prove matching minimax lower bounds. To our knowledge, this is the first complete set of strategies for bidders participating in auctions of this type.

## Efficiency Guarantees in Auctions with Budgets

Dobzinski, Shahar; Leme, Renato Paes
Tipo: Artigo de Revista Científica
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In settings where players have a limited access to liquidity, represented in the form of budget constraints, efficiency maximization has proven to be a challenging goal. In particular, the social welfare cannot be approximated by a better factor then the number of players. Therefore, the literature has mainly resorted to Pareto-efficiency as a way to achieve efficiency in such settings. While successful in some important scenarios, in many settings it is known that either exactly one incentive-compatible auction that always outputs a Pareto-efficient solution, or that no truthful mechanism can always guarantee a Pareto-efficient outcome. Traditionally, impossibility results can be avoided by considering approximations. However, Pareto-efficiency is a binary property (is either satisfied or not), which does not allow for approximations. In this paper we propose a new notion of efficiency, called \emph{liquid welfare}. This is the maximum amount of revenue an omniscient seller would be able to extract from a certain instance. We explain the intuition behind this objective function and show that it can be 2-approximated by two different auctions. Moreover, we show that no truthful algorithm can guarantee an approximation factor better than 4/3 with respect to the liquid welfare...

## A Dynamic Axiomatic Approach to First-Price Auctions

Hoy, Darrell; Jain, Kamal; Wilkens, Christopher A.
Tipo: Artigo de Revista Científica
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The first-price auction is popular in practice for its simplicity and transparency. Moreover, its potential virtues grow in complex settings where incentive compatible auctions may generate little or no revenue. Unfortunately, the first-price auction is poorly understood in theory because equilibrium is not {\em a priori} a credible predictor of bidder behavior. We take a dynamic approach to studying first-price auctions: rather than basing performance guarantees solely on static equilibria, we study the repeated setting and show that robust performance guarantees may be derived from simple axioms of bidder behavior. For example, as long as a loser raises her bid quickly, a standard first-price auction will generate at least as much revenue as a second-price auction. We generalize this dynamic technique to complex pay-your-bid auction settings and show that progressively stronger assumptions about bidder behavior imply progressively stronger guarantees about the auction's performance. Along the way, we find that the auctioneer's choice of bidding language is critical when generalizing beyond the single-item setting, and we propose a specific construction called the {\em utility-target auction} that performs well. The utility-target auction includes a bidder's final utility as an additional parameter...

## The Pollution Effect: Optimizing Keyword Auctions by Favoring Relevant Advertising

Linden, Greg; Meek, Christopher; Chickering, Max
Tipo: Artigo de Revista Científica
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## Combinatorial Auctions with Conflict-Based Externalities

Cheung, Yun Kuen; Henzinger, Monika; Hoefer, Martin; Starnberger, Martin
Tipo: Artigo de Revista Científica
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Combinatorial auctions (CA) are a well-studied area in algorithmic mechanism design. However, contrary to the standard model, empirical studies suggest that a bidder's valuation often does not depend solely on the goods assigned to him. For instance, in adwords auctions an advertiser might not want his ads to be displayed next to his competitors' ads. In this paper, we propose and analyze several natural graph-theoretic models that incorporate such negative externalities, in which bidders form a directed conflict graph with maximum out-degree $\Delta$. We design algorithms and truthful mechanisms for social welfare maximization that attain approximation ratios depending on $\Delta$. For CA, our results are twofold: (1) A lottery that eliminates conflicts by discarding bidders/items independent of the bids. It allows to apply any truthful $\alpha$-approximation mechanism for conflict-free valuations and yields an $\mathcal{O}(\alpha\Delta)$-approximation mechanism. (2) For fractionally sub-additive valuations, we design a rounding algorithm via a novel combination of a semi-definite program and a linear program, resulting in a cone program; the approximation ratio is $\mathcal{O}((\Delta \log \log \Delta)/\log \Delta)$. The ratios are almost optimal given existing hardness results. For the prominent application of adwords auctions...

## Ascending auctions and Walrasian equilibrium

Ben-Zwi, Oren; Lavi, Ron; Newman, Ilan
Tipo: Artigo de Revista Científica
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We present a family of submodular valuation classes that generalizes gross substitute. We show that Walrasian equilibrium always exist for one class in this family, and there is a natural ascending auction which finds it. We prove some new structural properties on gross-substitute auctions which, in turn, show that the known ascending auctions for this class (Gul-Stacchetti and Ausbel) are, in fact, identical. We generalize these two auctions, and provide a simple proof that they terminate in a Walrasian equilibrium.

## Knightian Analysis of the VCG Mechanism in Unrestricted Combinatorial Auctions

Chiesa, Alessandro; Micali, Silvio; Zhu, Zeyuan Allen
Tipo: Artigo de Revista Científica
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We consider auctions in which the players have very limited knowledge about their own valuations. Specifically, the only information that a Knightian player $i$ has about the profile of true valuations, $\theta^*$, consists of a set of distributions, from one of which $\theta_i^*$ has been drawn. The VCG mechanism guarantees very high social welfare both in single- and multi-good auctions, so long as Knightian players do not select strategies that are dominated. With such Knightian players, however, we prove that the VCG mechanism guarantees very poor social welfare in unrestricted combinatorial auctions.

## Limits of Efficiency in Sequential Auctions

Feldman, Michal; Lucier, Brendan; Syrgkanis, Vasilis
Tipo: Artigo de Revista Científica
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We study the efficiency of sequential first-price item auctions at (subgame perfect) equilibrium. This auction format has recently attracted much attention, with previous work establishing positive results for unit-demand valuations and negative results for submodular valuations. This leaves a large gap in our understanding between these valuation classes. In this work we resolve this gap on the negative side. In particular, we show that even in the very restricted case in which each bidder has either an additive valuation or a unit-demand valuation, there exist instances in which the inefficiency at equilibrium grows linearly with the minimum of the number of items and the number of bidders. Moreover, these inefficient equilibria persist even under iterated elimination of weakly dominated strategies. Our main result implies linear inefficiency for many natural settings, including auctions with gross substitute valuations, capacitated valuations, budget-additive valuations, and additive valuations with hard budget constraints on the payments. Another implication is that the inefficiency in sequential auctions is driven by the maximum number of items contained in any player's optimal set, and this is tight. For capacitated valuations...

## Efficiency Loss in Revenue Optimal Auctions

Abhishek, Vineet; Hajek, Bruce
Tipo: Artigo de Revista Científica
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We study efficiency loss in Bayesian revenue optimal auctions. We quantify this as the worst case ratio of loss in the realized social welfare to the social welfare that can be realized by an efficient auction. Our focus is on auctions with single-parameter buyers and where buyers' valuation sets are finite. For binary valued single-parameter buyers with independent (not necessarily identically distributed) private valuations, we show that the worst case efficiency loss ratio (ELR) is no worse than it is with only one buyer; moreover, it is at most 1/2. Moving beyond the case of binary valuations but restricting to single item auctions, where buyers' private valuations are independent and identically distributed, we obtain bounds on the worst case ELR as a function of number of buyers, cardinality of buyers' valuation set, and ratio of maximum to minimum possible values that buyers can have for the item.; Comment: 25 pages and 1 figure. A short version of this will appear in the 49th IEEE Conference on Decision and Control (CDC), 2010

## The Menu-Size Complexity of Auctions

Hart, Sergiu; Nisan, Noam
Tipo: Artigo de Revista Científica