26 research outputs found
Goal-oriented Dialogue Policy Learning from Failures
Reinforcement learning methods have been used for learning dialogue policies.
However, learning an effective dialogue policy frequently requires
prohibitively many conversations. This is partly because of the sparse rewards
in dialogues, and the very few successful dialogues in early learning phase.
Hindsight experience replay (HER) enables learning from failures, but the
vanilla HER is inapplicable to dialogue learning due to the implicit goals. In
this work, we develop two complex HER methods providing different trade-offs
between complexity and performance, and, for the first time, enabled HER-based
dialogue policy learning. Experiments using a realistic user simulator show
that our HER methods perform better than existing experience replay methods (as
applied to deep Q-networks) in learning rate
Towards Solving Text-based Games by Producing Adaptive Action Spaces
To solve a text-based game, an agent needs to formulate valid text commands
for a given context and find the ones that lead to success. Recent attempts at
solving text-based games with deep reinforcement learning have focused on the
latter, i.e., learning to act optimally when valid actions are known in
advance. In this work, we propose to tackle the first task and train a model
that generates the set of all valid commands for a given context. We try three
generative models on a dataset generated with Textworld. The best model can
generate valid commands which were unseen at training and achieve high
score on the test set
Learning a Policy for Opportunistic Active Learning
Active learning identifies data points to label that are expected to be the
most useful in improving a supervised model. Opportunistic active learning
incorporates active learning into interactive tasks that constrain possible
queries during interactions. Prior work has shown that opportunistic active
learning can be used to improve grounding of natural language descriptions in
an interactive object retrieval task. In this work, we use reinforcement
learning for such an object retrieval task, to learn a policy that effectively
trades off task completion with model improvement that would benefit future
tasks.Comment: EMNLP 2018 Camera Read
Frames: A Corpus for Adding Memory to Goal-Oriented Dialogue Systems
This paper presents the Frames dataset (Frames is available at
http://datasets.maluuba.com/Frames), a corpus of 1369 human-human dialogues
with an average of 15 turns per dialogue. We developed this dataset to study
the role of memory in goal-oriented dialogue systems. Based on Frames, we
introduce a task called frame tracking, which extends state tracking to a
setting where several states are tracked simultaneously. We propose a baseline
model for this task. We show that Frames can also be used to study memory in
dialogue management and information presentation through natural language
generation
Budgeted Reinforcement Learning in Continuous State Space
International audienceA Budgeted Markov Decision Process (BMDP) is an extension of a Markov Decision Process to critical applications requiring safety constraints. It relies on a notion of risk implemented in the shape of a cost signal constrained to lie below an-adjustable-threshold. So far, BMDPs could only be solved in the case of finite state spaces with known dynamics. This work extends the state-of-the-art to continuous spaces environments and unknown dynamics. We show that the solution to a BMDP is a fixed point of a novel Budgeted Bellman Optimality operator. This observation allows us to introduce natural extensions of Deep Reinforcement Learning algorithms to address large-scale BMDPs. We validate our approach on two simulated applications: spoken dialogue and autonomous driving