118,862 research outputs found
Mechanism Design without Money via Stable Matching
Mechanism design without money has a rich history in social choice
literature. Due to the strong impossibility theorem by Gibbard and
Satterthwaite, exploring domains in which there exist dominant strategy
mechanisms is one of the central questions in the field. We propose a general
framework, called the generalized packing problem (\gpp), to study the
mechanism design questions without payment. The \gpp\ possesses a rich
structure and comprises a number of well-studied models as special cases,
including, e.g., matroid, matching, knapsack, independent set, and the
generalized assignment problem.
We adopt the agenda of approximate mechanism design where the objective is to
design a truthful (or strategyproof) mechanism without money that can be
implemented in polynomial time and yields a good approximation to the socially
optimal solution. We study several special cases of \gpp, and give constant
approximation mechanisms for matroid, matching, knapsack, and the generalized
assignment problem. Our result for generalized assignment problem solves an
open problem proposed in \cite{DG10}.
Our main technical contribution is in exploitation of the approaches from
stable matching, which is a fundamental solution concept in the context of
matching marketplaces, in application to mechanism design. Stable matching,
while conceptually simple, provides a set of powerful tools to manage and
analyze self-interested behaviors of participating agents. Our mechanism uses a
stable matching algorithm as a critical component and adopts other approaches
like random sampling and online mechanisms. Our work also enriches the stable
matching theory with a new knapsack constrained matching model
Human-Machine Collaborative Optimization via Apprenticeship Scheduling
Coordinating agents to complete a set of tasks with intercoupled temporal and
resource constraints is computationally challenging, yet human domain experts
can solve these difficult scheduling problems using paradigms learned through
years of apprenticeship. A process for manually codifying this domain knowledge
within a computational framework is necessary to scale beyond the
``single-expert, single-trainee" apprenticeship model. However, human domain
experts often have difficulty describing their decision-making processes,
causing the codification of this knowledge to become laborious. We propose a
new approach for capturing domain-expert heuristics through a pairwise ranking
formulation. Our approach is model-free and does not require enumerating or
iterating through a large state space. We empirically demonstrate that this
approach accurately learns multifaceted heuristics on a synthetic data set
incorporating job-shop scheduling and vehicle routing problems, as well as on
two real-world data sets consisting of demonstrations of experts solving a
weapon-to-target assignment problem and a hospital resource allocation problem.
We also demonstrate that policies learned from human scheduling demonstration
via apprenticeship learning can substantially improve the efficiency of a
branch-and-bound search for an optimal schedule. We employ this human-machine
collaborative optimization technique on a variant of the weapon-to-target
assignment problem. We demonstrate that this technique generates solutions
substantially superior to those produced by human domain experts at a rate up
to 9.5 times faster than an optimization approach and can be applied to
optimally solve problems twice as complex as those solved by a human
demonstrator.Comment: Portions of this paper were published in the Proceedings of the
International Joint Conference on Artificial Intelligence (IJCAI) in 2016 and
in the Proceedings of Robotics: Science and Systems (RSS) in 2016. The paper
consists of 50 pages with 11 figures and 4 table
A Dual Characterization of Incentive Efficiency
We show that incentive e cient allocations in economies with adverse se- lection and moral hazard can be determined as optimal solutions to a linear programming problem and we use duality theory to obtain a complete charac- terization of the optima. Our dual analysis identi es welfare e ects associated with the incentives of the agents to truthfully reveal their private information. Because these welfare e ects may generate non-convexities, incentive e cient allocations may involve randomization. Other properties of incentive e cient allocations are also derived
Making recommendations bandwidth aware
This paper asks how much we can gain in terms of bandwidth and user
satisfaction, if recommender systems became bandwidth aware and took into
account not only the user preferences, but also the fact that they may need to
serve these users under bandwidth constraints, as is the case over wireless
networks. We formulate this as a new problem in the context of index coding: we
relax the index coding requirements to capture scenarios where each client has
preferences associated with messages. The client is satisfied to receive any
message she does not already have, with a satisfaction proportional to her
preference for that message. We consistently find, over a number of scenarios
we sample, that although the optimization problems are in general NP-hard,
significant bandwidth savings are possible even when restricted to polynomial
time algorithms
Efficiency of Truthful and Symmetric Mechanisms in One-sided Matching
We study the efficiency (in terms of social welfare) of truthful and
symmetric mechanisms in one-sided matching problems with {\em dichotomous
preferences} and {\em normalized von Neumann-Morgenstern preferences}. We are
particularly interested in the well-known {\em Random Serial Dictatorship}
mechanism. For dichotomous preferences, we first show that truthful, symmetric
and optimal mechanisms exist if intractable mechanisms are allowed. We then
provide a connection to online bipartite matching. Using this connection, it is
possible to design truthful, symmetric and tractable mechanisms that extract
0.69 of the maximum social welfare, which works under assumption that agents
are not adversarial. Without this assumption, we show that Random Serial
Dictatorship always returns an assignment in which the expected social welfare
is at least a third of the maximum social welfare. For normalized von
Neumann-Morgenstern preferences, we show that Random Serial Dictatorship always
returns an assignment in which the expected social welfare is at least
\frac{1}{e}\frac{\nu(\opt)^2}{n}, where \nu(\opt) is the maximum social
welfare and is the number of both agents and items. On the hardness side,
we show that no truthful mechanism can achieve a social welfare better than
\frac{\nu(\opt)^2}{n}.Comment: 13 pages, 1 figur
Identification with Latent Choice Sets
In a common experimental format, individuals are randomly assigned to either
a treatment group with access to a program or a control group without access.
In such experiments, analyzing the average effects of the treatment of program
access may be hindered by the problem that some control individuals do not
comply with their assigned status and receive program access from outside the
experiment. Available tools to account for such a problem typically require the
researcher to observe the receipt of program access for every individual.
However, in many experiments, this is not the case as data is not collected on
where any individual received access. In this paper, I develop a framework to
show how data on only each individual's treatment assignment status, program
participation decision and outcome can be exploited to learn about the average
effects of program access. I propose a nonparametric selection model with
latent choice sets to relate where access was received to the treatment
assignment status, participation decision and outcome, and a linear programming
procedure to compute the identified set for parameters evaluating the average
effects of program access in this model. I illustrate the framework by
analyzing the average effects of Head Start preschool access using the Head
Start Impact Study. I find that the provision of Head Start access induces
parents to enroll their child into Head Start and also positively impacts test
scores, and that these effects heterogeneously depend on the availability of
access to an alternative preschool.Comment: 23 pages, plus 32 pages of supplemental appendi
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