10,762 research outputs found
Decision Forest: A Nonparametric Approach to Modeling Irrational Choice
Customer behavior is often assumed to follow weak rationality, which implies
that adding a product to an assortment will not increase the choice probability
of another product in that assortment. However, an increasing amount of
research has revealed that customers are not necessarily rational when making
decisions. In this paper, we propose a new nonparametric choice model that
relaxes this assumption and can model a wider range of customer behavior, such
as decoy effects between products. In this model, each customer type is
associated with a binary decision tree, which represents a decision process for
making a purchase based on checking for the existence of specific products in
the assortment. Together with a probability distribution over customer types,
we show that the resulting model -- a decision forest -- is able to represent
any customer choice model, including models that are inconsistent with weak
rationality. We theoretically characterize the depth of the forest needed to
fit a data set of historical assortments and prove that with high probability,
a forest whose depth scales logarithmically in the number of assortments is
sufficient to fit most data sets. We also propose two practical algorithms --
one based on column generation and one based on random sampling -- for
estimating such models from data. Using synthetic data and real transaction
data exhibiting non-rational behavior, we show that the model outperforms both
rational and non-rational benchmark models in out-of-sample predictive ability.Comment: The paper is forthcoming in Management Science (accepted on July 25,
2021
Topologies on Types: Connections
For different purposes, economists may use different topologies on types. We char- acterize the relationship among these various topologies. First, we show that for any general types, convergence in the uniform-weak topology implies convergence in both the strategic topology and the uniform strategic topology. Second, we explicitly con- struct a type which is not the limit of any
finite types under the uniform strategic topology, showing that the uniform strategic topology is strictly fi
ner than the strategic topology. With these results, we can linearly rank various topologies on the universal type space, which gives a clear picture of the relationship between the implication of types for beliefs and their implication for behaviors.the universal type space, the strategic topology; the uniform strategic topology; the uniform-weak topology; interim correlated rationalizable actions
A Unified Approach to Information, Knowledge, and Stability
Within the context of strategic interaction, we provide a unified framework for analyzing information, knowledge, and the "stable" pattern of behavior. We first study the related interactive epistemology and, in particular, show an equivalence theorem between a strictly dominated strategy and a never-best reply in terms of epistemic states. We then explore epistemic foundations behind the fascinating idea of stability due to J. von Neumann and O. Morgenstern. The major features of our approach are: (i)unlike the ad hoc semantic model of knowledge, the state space is constructed by Harsanyi’s types that are explicitly formulated by Epstein and Wang (Econometrica 64, 1996, 1343-1373); (ii)players may have general preferences, including subjective expected utility and non-expected utility; and (iii) players may be boundedly rational and have non-partitional information structuresepistemic games; Harsanyi's types; interactive epistemology; stability; non-expected utility; bounded rationality
Symmetry of superconducting states with two orbitals on a tetragonal lattice: application to
We use group theory to classify the superconducting states of systems with
two orbitals on a tetragonal lattice. The orbital part of the superconducting
gap function can be either symmetric or anti-symmetric. For the orbital
symmetric state, the parity is even for spin singlet and odd for spin triplet;
for the orbital anti-symmetric state, the parity is odd for spin singlet and
even for spin triplet. The gap basis functions are obtained with the use of the
group chain scheme by taking into account the spin-orbit coupling. In the weak
pairing limit, the orbital anti-symmetric state is only stable for the
degenerate orbitals. Possible application to iron-based superconductivity is
discussed.Comment: published versio
Quantum Robot: Structure, Algorithms and Applications
A kind of brand-new robot, quantum robot, is proposed through fusing quantum
theory with robot technology. Quantum robot is essentially a complex quantum
system and it is generally composed of three fundamental parts: MQCU (multi
quantum computing units), quantum controller/actuator, and information
acquisition units. Corresponding to the system structure, several learning
control algorithms including quantum searching algorithm and quantum
reinforcement learning are presented for quantum robot. The theoretic results
show that quantum robot can reduce the complexity of O(N^2) in traditional
robot to O(N^(3/2)) using quantum searching algorithm, and the simulation
results demonstrate that quantum robot is also superior to traditional robot in
efficient learning by novel quantum reinforcement learning algorithm.
Considering the advantages of quantum robot, its some potential important
applications are also analyzed and prospected.Comment: 19 pages, 4 figures, 2 table
Correlation of microwave dielectric properties and normal vibration modes of xBa(Mg1/3Ta2/3)O3-(1-x)Ba(Mg1/3Nb2/3)O3 ceramics : II. Infrared spectroscopy
[[abstract]]The relationship between the microwave dielectric properties and the IR active phonons of xBa(Mg1/3Ta2/3)O3 –(12x)Ba(Mg1/3Nb2/3)O3 ceramics was investigated. The IR modes were assigned, and the origin of dielectric response was determined. Among the 15 prominent IR modes, we found that the normal vibrations of the O layers and that of the Ta/Nb layers are strongly correlated to the measured dispersion parameters, such as the resonant strength ~4pr! and the damping coefficient ~g!. The frequency shifts of the normal modes of the O layers and that of the Ta/Nb layers explain the linear decrease of microwave dielectric constant ~K! as x increases, while the width of these modes correlate with the Q3 f value.[[notice]]補正完畢[[journaltype]]國內[[incitationindex]]SCI[[booktype]]紙
Iterated Strict Dominance in General Games
We offer a definition of iterated elimination of strictly dominated strategies (IESDS) for games with (in)finite players, (non)compact strategy sets, and (dis)continuous payoff functions. IESDS is always a well-defined order independent procedure that can be used to solve Nash equilibrium in dominance-solvable games. We characterize IESDS by means of a "stability" criterion, and offer a sufficient and necessary epistemic condition for IESDS. We show by an example that IESDS may generate spurious Nash equilibria in the class of Reny's better-reply secure games. We provide sufficient/necessary conditions under which IESDS preserves the set of Nash equilibria. Nous donnons une définition de l’élimination itérative des stratégies qui sont strictement donimées (EISSD) pour les jeux avec un nombre fini (ou infini) de joueurs , des ensembles de stratégies compactes (ou non-compactes), et des fonctions de gains continues (ou non-continues). Le processus EISSD est bien défini et indépendant de l’ordre d’élimination. Nous donnons une caractérisation du processus EISSD en utilisant un critère de stabilité et offrons une condition épistémologique. Nous démontrons que le processus EISSD peut produire des équilibres faux dans la classe des jeux de meilleures réponses sécuritaires de Reny. Nous donnons des conditions nécessaires et suffisantes pour que le processus EISSD conserve l’ensemble des équilibre de Nash.game theory, strict dominance, iterated elimination, Nash equilibrium, Reny's better-reply secure games., théorie des jeux, dominance stricte, élimination itérative, équilibre de Nash, jeux de meilleures réponses sécuritaires de Reny
Information Design in Optimal Auctions
We study the information design problem in a single-unit auction setting. The
information designer controls independent private signals according to which
the buyers infer their binary private values. Assuming that the seller adopts
the optimal auction due to Myerson (1981) in response, we characterize both the
buyer-optimal information structure, which maximizes the buyers' surplus, and
the sellerworst information structure, which minimizes the seller's revenue. We
translate both information design problems into finite-dimensional, constrained
optimization problems in which one can explicitly solve for the optimal
information structures. In contrast to the case with one buyer (Roesler and
Szentes, 2017), we show that with two or more buyers, the symmetric
buyer-optimal information structure is different from the symmetric
seller-worst information structure. The good is always sold under the
seller-worst information structure but not under the buyer-optimal information
structure. Nevertheless, as the number of buyers goes to infinity, both
symmetric information structures converge to no disclosure. We also show that
in an ex ante symmetric setting, an asymmetric information structure is never
seller-worst but can generate a strictly higher surplus for the buyers than the
symmetric buyer-optimal information structure
A Customizable Generator for Comic-Style Visual Narrative
We present a theory-inspired visual narrative generator that incorporates
comic-authoring idioms, which transfers the conceptual principles of comics
into system layers that integrate the theories to create comic content. The
generator creates comics through sequential decision-making across layers from
panel composition, object positions, panel transitions, and narrative elements.
Each layer's decisions are based on narrative goals and follow the respective
layer idioms of the medium. Cohn's narrative grammar provides the overall story
arc. Photographic compositions inspired by the rule of thirds is used to
provide panel compositions. McCloud's proposed panel transitions based on focus
shifts between scene, character, and temporal changes are encoded in the
transition layer. Finally, common overlay symbols (such as the exclamation) are
added based on analyzing action verbs using an action-verb ontology. We
demonstrate the variety of generated comics through various settings with
example outputs. The generator and associated modules could be a useful system
for visual narrative authoring and for further research into computational
models of visual narrative understanding
Implementation with Uncertain Evidence
We study a full implementation problem with hard evidence where the state is
common knowledge but agents face uncertainty about the evidence endowments of
other agents. We identify a necessary and sufficient condition for
implementation in mixed-strategy Bayesian Nash equilibria called No Perfect
Deceptions. The implementing mechanism requires only two agents and a finite
message space, imposes transfers only off the equilibrium, and invoke no device
with "...questionable features..." such as integer or modulo games. Requiring
only implementation in pure-strategy equilibria weakens the necessary and
sufficient condition to No Pure-Perfect Deceptions. In general type spaces
where the state is not common knowledge, a condition called higher-order
measurability is necessary and sufficient for rationalizable implementation
with arbitrarily small transfers alongside
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