Página 9 dos resultados de 1418 itens digitais encontrados em 0.003 segundos

## Electronic reverse auctions in the federal government

Fonte: Monterey, California. Naval Postgraduate School
Publicador: Monterey, California. Naval Postgraduate School

Tipo: Relatório
Formato: x, 80 p.: ill.;28 cm.

Relevância na Pesquisa

27.09%

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

Link permanente para citações:

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

Fonte: Banco Mundial
Publicador: Banco Mundial

Tipo: Publications & Research :: Policy Research Working Paper

ENGLISH

Relevância na Pesquisa

27.09%

#AFFILIATED ORGANIZATIONS#AUCTION#AUCTION MECHANISMS#AUCTIONS#BID#BID EVALUATION#BIDDER#BIDDERS#BIDDING#BIDS#BUNDLING

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.

Link permanente para citações:

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

Fonte: World Bank, Washington, DC
Publicador: World Bank, Washington, DC

Tipo: Publications & Research :: Viewpoint; Publications & Research

ENGLISH

Relevância na Pesquisa

27.09%

#CONCESSIONS#AUCTIONS#BIDDING#BIDS#PRICES#COLLUSION#SEALED BIDS#OPEN BIDS#SEQUENTIAL BIDDING#SIMULTANEOUS BIDDING#PREQUALIFICATION ASSETS

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.

Link permanente para citações:

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

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

Relevância na Pesquisa

27.09%

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...

Link permanente para citações:

## Essays on Applied Microeconomics

Fonte: Harvard University
Publicador: Harvard University

Tipo: Thesis or Dissertation

EN_US

Relevância na Pesquisa

27.09%

#Economics#Economics, Commerce-Business#Economic theory#Auctions#Entrepreneurial finance#Industrial organizations#Internet advertising#Mechanism design#Venture capital

Empirical and theoretical topics in applied microeconomics are discussed in this dissertation. The first essay identifies and measures managerial advantages from access to high-quality deals in venture capital investments. The underlying social network of Harvard Business School MBA venture capitalists and entrepreneurs is used to proxy availability of deal access. Random section assignment of HBS MBA graduates provides a key exogenous variation for identification. Being socially connected to peer venture capital firms and private equity seeking startups leads to more deal flow, larger asset under management and better performance in the inaugural funds of HBS-executive run venture capital firms. The second essay presents a two-stage model of competing ad auctions. Search engines attract users via Cournot-style competition. Meanwhile, each advertiser must pay a participation cost to use each ad platform. Advertiser entry strategies using symmetric Bayes-Nash equilibrium that lead to the Vickrey-Clarke-Groves outcome of the ad auctions are derived. Consistent with the model predictions, empirical evidence shows that multi-homing advertisers are larger than single-homing advertisers. Comparative statics on consumer choice parameters...

Link permanente para citações:

## Virtual Worlds: Fast and Strategyproof Auctions for Dynamic Resource Allocation

Fonte: Association for Computing Machinery
Publicador: Association for Computing Machinery

Tipo: Monograph or Book

EN_US

Relevância na Pesquisa

27.09%

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

Link permanente para citações:

## Efficient Interdependent Value Combinatorial Auctions with Single Minded Bidders

Fonte: AAAI Press
Publicador: AAAI Press

Tipo: Conference Paper

EN_US

Relevância na Pesquisa

27.09%

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

Link permanente para citações:

## Combinatorial Auctions with Restricted Complements

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 18/05/2012

Relevância na Pesquisa

27.09%

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...

Link permanente para citações:

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

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

27.09%

#Computer Science - Computer Science and Game Theory#Computer Science - Artificial Intelligence#Computer Science - Computational Complexity#Computer Science - Learning

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...

Link permanente para citações:

## Online learning in repeated auctions

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 18/11/2015

Relevância na Pesquisa

27.09%

#Computer Science - Computer Science and Game Theory#Computer Science - Learning#Statistics - Machine Learning#Primary 62L05, secondary 62C20

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.

Link permanente para citações:

## Efficiency Guarantees in Auctions with Budgets

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 25/04/2013

Relevância na Pesquisa

27.09%

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...

Link permanente para citações:

## A Dynamic Axiomatic Approach to First-Price Auctions

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 29/04/2013

Relevância na Pesquisa

27.09%

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...

Link permanente para citações:

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

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 28/09/2011

Relevância na Pesquisa

27.09%

#Computer Science - Computer Science and Game Theory#Computer Science - Computers and Society#Computer Science - Information Retrieval#K.4.4#J.4

Most search engines sell slots to place advertisements on the search results
page through keyword auctions. Advertisers offer bids for how much they are
willing to pay when someone enters a search query, sees the search results, and
then clicks on one of their ads. Search engines typically order the
advertisements for a query by a combination of the bids and expected
clickthrough rates for each advertisement. In this paper, we extend a model of
Yahoo's and Google's advertising auctions to include an effect where repeatedly
showing less relevant ads has a persistent impact on all advertising on the
search engine, an impact we designate as the pollution effect. In Monte-Carlo
simulations using distributions fitted to Yahoo data, we show that a modest
pollution effect is sufficient to dramatically change the advertising rank
order that yields the optimal advertising revenue for a search engine. In
addition, if a pollution effect exists, it is possible to maximize revenue
while also increasing advertiser, and publisher utility. Our results suggest
that search engines could benefit from making relevant advertisements less
expensive and irrelevant advertisements more costly for advertisers than is the
current practice.; Comment: Presented at the Fifth Workshop on Ad Auctions...

Link permanente para citações:

## Combinatorial Auctions with Conflict-Based Externalities

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 30/09/2015

Relevância na Pesquisa

27.09%

#Computer Science - Computer Science and Game Theory#Computer Science - Data Structures and Algorithms

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...

Link permanente para citações:

## Ascending auctions and Walrasian equilibrium

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

27.09%

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.

Link permanente para citações:

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

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 25/03/2014

Relevância na Pesquisa

27.09%

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.

Link permanente para citações:

## Limits of Efficiency in Sequential Auctions

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 10/09/2013

Relevância na Pesquisa

27.09%

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...

Link permanente para citações:

## Efficiency Loss in Revenue Optimal Auctions

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

27.09%

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

Link permanente para citações:

## The Menu-Size Complexity of Auctions

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 22/04/2013

Relevância na Pesquisa

27.09%

We consider the menu size of auctions as a measure of auction complexity and
study how it affects revenue. Our setting has a single revenue-maximizing
seller selling two or more heterogeneous items to a single buyer whose private
values for the items are drawn from a (possibly correlated) known distribution,
and whose valuation is additive over the items. We show that the revenue may
increase arbitrarily with menu size and that a bounded menu size can not ensure
any positive fraction of the optimal revenue. The menu size turns out to "nail
down" the revenue properties of deterministic auctions: their menu size may be
at most exponential in the number of items and indeed their revenue may be
larger than that achievable by the simplest types of auctions by a factor that
is exponential in the number of items but no larger. Our model is related to a
previously studied "unit-demand" model and our results also answer an open
problem in that model.

Link permanente para citações:

## Truth Revelation in Approximately Efficient Combinatorial Auctions

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 15/02/2002

Relevância na Pesquisa

27.09%

Some important classical mechanisms considered in Microeconomics and Game
Theory require the solution of a difficult optimization problem. This is true
of mechanisms for combinatorial auctions, which have in recent years assumed
practical importance, and in particular of the gold standard for combinatorial
auctions, the Generalized Vickrey Auction (GVA). Traditional analysis of these
mechanisms - in particular, their truth revelation properties - assumes that
the optimization problems are solved precisely. In reality, these optimization
problems can usually be solved only in an approximate fashion. We investigate
the impact on such mechanisms of replacing exact solutions by approximate ones.
Specifically, we look at a particular greedy optimization method. We show that
the GVA payment scheme does not provide for a truth revealing mechanism. We
introduce another scheme that does guarantee truthfulness for a restricted
class of players. We demonstrate the latter property by identifying natural
properties for combinatorial auctions and showing that, for our restricted
class of players, they imply that truthful strategies are dominant. Those
properties have applicability beyond the specific auction studied.; Comment: Submitted to a Journal. A preliminary version appeared in EC'99

Link permanente para citações: