452 research outputs found
Hybrid Tractable Classes of Binary Quantified Constraint Satisfaction Problems
In this paper, we investigate the hybrid tractability of binary Quantified
Constraint Satisfaction Problems (QCSPs). First, a basic tractable class of
binary QCSPs is identified by using the broken-triangle property. In this
class, the variable ordering for the broken-triangle property must be same as
that in the prefix of the QCSP. Second, we break this restriction to allow that
existentially quantified variables can be shifted within or out of their
blocks, and thus identify some novel tractable classes by introducing the
broken-angle property. Finally, we identify a more generalized tractable class,
i.e., the min-of-max extendable class for QCSPs
BayesNAS: A Bayesian Approach for Neural Architecture Search
One-Shot Neural Architecture Search (NAS) is a promising method to
significantly reduce search time without any separate training. It can be
treated as a Network Compression problem on the architecture parameters from an
over-parameterized network. However, there are two issues associated with most
one-shot NAS methods. First, dependencies between a node and its predecessors
and successors are often disregarded which result in improper treatment over
zero operations. Second, architecture parameters pruning based on their
magnitude is questionable. In this paper, we employ the classic Bayesian
learning approach to alleviate these two issues by modeling architecture
parameters using hierarchical automatic relevance determination (HARD) priors.
Unlike other NAS methods, we train the over-parameterized network for only one
epoch then update the architecture. Impressively, this enabled us to find the
architecture on CIFAR-10 within only 0.2 GPU days using a single GPU.
Competitive performance can be also achieved by transferring to ImageNet. As a
byproduct, our approach can be applied directly to compress convolutional
neural networks by enforcing structural sparsity which achieves extremely
sparse networks without accuracy deterioration.Comment: International Conference on Machine Learning 201
Causal Mediation Analysis with a Three-Dimensional Image Mediator
Causal mediation analysis is increasingly abundant in biology, psychology,
and epidemiology studies, etc. In particular, with the advent of the big data
era, the issue of high-dimensional mediators is becoming more prevalent. In
neuroscience, with the widespread application of magnetic resonance technology
in the field of brain imaging, studies on image being a mediator emerged. In
this study, a novel causal mediation analysis method with a three-dimensional
image mediator is proposed. We define the average casual effects under the
potential outcome framework, explore several sufficient conditions for the
valid identification, and develop techniques for estimation and inference. To
verify the effectiveness of the proposed method, a series of simulations under
various scenarios is performed. Finally, the proposed method is applied to a
study on the causal effect of mothers delivery mode on
childs IQ development. It is found that the white matter in certain
regions of the frontal-temporal areas has mediating effects.Comment: 35 pages, 9 figure
Reinforced Mnemonic Reader for Machine Reading Comprehension
In this paper, we introduce the Reinforced Mnemonic Reader for machine
reading comprehension tasks, which enhances previous attentive readers in two
aspects. First, a reattention mechanism is proposed to refine current
attentions by directly accessing to past attentions that are temporally
memorized in a multi-round alignment architecture, so as to avoid the problems
of attention redundancy and attention deficiency. Second, a new optimization
approach, called dynamic-critical reinforcement learning, is introduced to
extend the standard supervised method. It always encourages to predict a more
acceptable answer so as to address the convergence suppression problem occurred
in traditional reinforcement learning algorithms. Extensive experiments on the
Stanford Question Answering Dataset (SQuAD) show that our model achieves
state-of-the-art results. Meanwhile, our model outperforms previous systems by
over 6% in terms of both Exact Match and F1 metrics on two adversarial SQuAD
datasets.Comment: Published in 27th International Joint Conference on Artificial
Intelligence (IJCAI), 201
Multispectral and Hyperspectral Image Fusion by MS/HS Fusion Net
Hyperspectral imaging can help better understand the characteristics of
different materials, compared with traditional image systems. However, only
high-resolution multispectral (HrMS) and low-resolution hyperspectral (LrHS)
images can generally be captured at video rate in practice. In this paper, we
propose a model-based deep learning approach for merging an HrMS and LrHS
images to generate a high-resolution hyperspectral (HrHS) image. In specific,
we construct a novel MS/HS fusion model which takes the observation models of
low-resolution images and the low-rankness knowledge along the spectral mode of
HrHS image into consideration. Then we design an iterative algorithm to solve
the model by exploiting the proximal gradient method. And then, by unfolding
the designed algorithm, we construct a deep network, called MS/HS Fusion Net,
with learning the proximal operators and model parameters by convolutional
neural networks. Experimental results on simulated and real data substantiate
the superiority of our method both visually and quantitatively as compared with
state-of-the-art methods along this line of research.Comment: 10 pages, 7 figure
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