982 research outputs found
On the classification of certain 1-connected 7-manifolds and related problems
In this article, we give a classification of closed, smooth, spin,
1-connected 7-manifolds whose integral cohomology ring is isomorphic to that of
. We also prove that if a closed, smooth, spin,
1-connected 7-manifold has integral cohomology ring isomorphic to that of
or , then it admits a Riemannian
metric with positive Ricci curvature.Comment: 20 page
Relative Importance Sampling For Off-Policy Actor-Critic in Deep Reinforcement Learning
Off-policy learning is more unstable compared to on-policy learning in
reinforcement learning (RL). One reason for the instability of off-policy
learning is a discrepancy between the target () and behavior (b) policy
distributions. The discrepancy between and b distributions can be
alleviated by employing a smooth variant of the importance sampling (IS), such
as the relative importance sampling (RIS). RIS has parameter
which controls smoothness. To cope with instability, we present the first
relative importance sampling-off-policy actor-critic (RIS-Off-PAC) model-free
algorithms in RL. In our method, the network yields a target policy (the
actor), a value function (the critic) assessing the current policy ()
using samples drawn from behavior policy. We use action value generated from
the behavior policy in reward function to train our algorithm rather than from
the target policy. We also use deep neural networks to train both actor and
critic. We evaluated our algorithm on a number of Open AI Gym benchmark
problems and demonstrate better or comparable performance to several
state-of-the-art RL baselines
MatchZoo: A Learning, Practicing, and Developing System for Neural Text Matching
Text matching is the core problem in many natural language processing (NLP)
tasks, such as information retrieval, question answering, and conversation.
Recently, deep leaning technology has been widely adopted for text matching,
making neural text matching a new and active research domain. With a large
number of neural matching models emerging rapidly, it becomes more and more
difficult for researchers, especially those newcomers, to learn and understand
these new models. Moreover, it is usually difficult to try these models due to
the tedious data pre-processing, complicated parameter configuration, and
massive optimization tricks, not to mention the unavailability of public codes
sometimes. Finally, for researchers who want to develop new models, it is also
not an easy task to implement a neural text matching model from scratch, and to
compare with a bunch of existing models. In this paper, therefore, we present a
novel system, namely MatchZoo, to facilitate the learning, practicing and
designing of neural text matching models. The system consists of a powerful
matching library and a user-friendly and interactive studio, which can help
researchers: 1) to learn state-of-the-art neural text matching models
systematically, 2) to train, test and apply these models with simple
configurable steps; and 3) to develop their own models with rich APIs and
assistance
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