26,441 research outputs found
Periodic long-time behaviour for an approximate model of nematic polymers
We study the long-time behaviour of a nonlinear Fokker-Planck equation, which
models the evolution of rigid polymers in a given flow, after a closure
approximation. The aim of this work is twofold: first, we propose a microscopic
derivation of the classical Doi closure, at the level of the kinetic equation ;
second, we prove the convergence of the solution to the Fokker-Planck equation
to periodic solutions in the long-time limit
Mathematical analysis of a one-dimensional model for an aging fluid
We study mathematically a system of partial differential equations arising in
the modelling of an aging fluid, a particular class of non Newtonian fluids. We
prove well-posedness of the equations in appropriate functional spaces and
investigate the longtime behaviour of the solutions
NPRF: A Neural Pseudo Relevance Feedback Framework for Ad-hoc Information Retrieval
Pseudo-relevance feedback (PRF) is commonly used to boost the performance of
traditional information retrieval (IR) models by using top-ranked documents to
identify and weight new query terms, thereby reducing the effect of
query-document vocabulary mismatches. While neural retrieval models have
recently demonstrated strong results for ad-hoc retrieval, combining them with
PRF is not straightforward due to incompatibilities between existing PRF
approaches and neural architectures. To bridge this gap, we propose an
end-to-end neural PRF framework that can be used with existing neural IR models
by embedding different neural models as building blocks. Extensive experiments
on two standard test collections confirm the effectiveness of the proposed NPRF
framework in improving the performance of two state-of-the-art neural IR
models.Comment: Full paper in EMNLP 201
Kernel Exponential Family Estimation via Doubly Dual Embedding
We investigate penalized maximum log-likelihood estimation for exponential
family distributions whose natural parameter resides in a reproducing kernel
Hilbert space. Key to our approach is a novel technique, doubly dual embedding,
that avoids computation of the partition function. This technique also allows
the development of a flexible sampling strategy that amortizes the cost of
Monte-Carlo sampling in the inference stage. The resulting estimator can be
easily generalized to kernel conditional exponential families. We establish a
connection between kernel exponential family estimation and MMD-GANs, revealing
a new perspective for understanding GANs. Compared to the score matching based
estimators, the proposed method improves both memory and time efficiency while
enjoying stronger statistical properties, such as fully capturing smoothness in
its statistical convergence rate while the score matching estimator appears to
saturate. Finally, we show that the proposed estimator empirically outperforms
state-of-the-artComment: 22 pages, 20 figures; AISTATS 201
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