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 Reinforcement Learning


Spectrum Management in Dynamic Spectrum Access: A Deep Reinforcement Learning Approach

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Generally, in dynamic spectrum access (DSA) networks, co-operations and centralized control are unavailable and DSA users have to carry out wireless transmissions individually. DSA users have to know other users' behaviors by sensing and analyzing wireless environments, so that DSA users can adjust their parameters properly and carry out effective wireless transmissions. In this thesis, machine learning and deep learning technologies are leveraged in DSA network to enable appropriate and intelligent spectrum managements, including both spectrum access and power allocations. Accordingly, a novel spectrum management framework utilizing deep reinforcement learning is proposed, in which deep reinforcement learning is employed to accurately learn wireless environments and generate optimal spectrum management strategies to adapt to the variations of wireless environments. Due to the model-free nature of reinforcement learning, DSA users only need to directly interact with environments to obtain optimal strategies rather than relying on accurate channel estimations.


No-Regret Exploration in Goal-Oriented Reinforcement Learning

arXiv.org Machine Learning

Many popular reinforcement learning problems (e.g., navigation in a maze, some Atari games, mountain car) are instances of the so-called episodic setting or stochastic shortest path (SSP) problem, where an agent has to achieve a predefined goal state (e.g., the top of the hill) while maximizing the cumulative reward or minimizing the cumulative cost. Despite its popularity, most of the literature studying the exploration-exploitation dilemma either focused on different problems (i.e., fixed-horizon and infinite-horizon) or made the restrictive loop-free assumption (which implies that no same state can be visited twice during any episode). In this paper, we study the general SSP setting and introduce the algorithm UC-SSP whose regret scales as $\displaystyle \widetilde{O}(c_{\max}^{3/2} c_{\min}^{-1/2} D S \sqrt{ A D K})$ after $K$ episodes for any unknown SSP with $S$ non-terminal states, $A$ actions, an SSP-diameter of $D$ and positive costs in $[c_{\min}, c_{\max}]$. UC-SSP is thus the first learning algorithm with vanishing regret in the theoretically challenging setting of episodic RL.


Hierarchical Cooperative Multi-Agent Reinforcement Learning with Skill Discovery

arXiv.org Machine Learning

Human players in professional team sports achieve high level coordination by dynamically choosing complementary skills and executing primitive actions to perform these skills. As a step toward creating intelligent agents with this capability for fully cooperative multi-agent settings, we propose a two-level hierarchical multi-agent reinforcement learning (MARL) algorithm with unsupervised skill discovery. Agents learn useful and distinct skills at the low level via independent Q-learning, while they learn to select complementary latent skill variables at the high level via centralized multi-agent training with an extrinsic team reward. The set of low-level skills emerges from an intrinsic reward that solely promotes the decodability of latent skill variables from the trajectory of a low-level skill, without the need for hand-crafted rewards for each skill. For scalable decentralized execution, each agent independently chooses latent skill variables and primitive actions based on local observations. Our overall method enables the use of general cooperative MARL algorithms for training high level policies and single-agent RL for training low level skills. Experiments on a stochastic high dimensional team game show the emergence of useful skills and cooperative team play. The interpretability of the learned skills show the promise of the proposed method for achieving human-AI cooperation in team sports games.


Improving Network Automation and Security with Artificial Intelligence - IT Peer Network

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Communication service providers (CommSPs) are already saving money and generating revenue from network transformation investments. There is an expectation these benefits will continue to increase as NFV functions scale across the various elements of the infrastructure--enterprise, radio access network, wireless core, cable and cloud. New 5G and edge computing use cases promise to deliver new revenue along with even more data that must be moved, stored, processed and analyzed. The industry is looking to Artificial Intelligence (AI) and Machine Learning (ML) to enable CommSPs to solve problems and unlock value for their own business operations and their customers. As an example, distributed AI based on reinforcement learning will play a key role in building automated and self-managed networks.


Risk-Averse Trust Region Optimization for Reward-Volatility Reduction

arXiv.org Machine Learning

In real-world decision-making problems, for instance in the fields of finance, robotics or autonomous driving, keeping uncertainty under control is as important as maximizing expected returns. Risk aversion has been addressed in the reinforcement learning literature through risk measures related to the variance of returns. However, in many cases, the risk is measured not only on a long-term perspective, but also on the step-wise rewards (e.g., in trading, to ensure the stability of the investment bank, it is essential to monitor the risk of portfolio positions on a daily basis). In this paper, we define a novel measure of risk, which we call reward volatility, consisting of the variance of the rewards under the state-occupancy measure. We show that the reward volatility bounds the return variance so that reducing the former also constrains the latter. We derive a policy gradient theorem with a new objective function that exploits the mean-volatility relationship, and develop an actor-only algorithm. Furthermore, thanks to the linearity of the Bellman equations defined under the new objective function, it is possible to adapt the well-known policy gradient algorithms with monotonic improvement guarantees such as TRPO in a risk-averse manner. Finally, we test the proposed approach in two simulated financial environments.


VALAN: Vision and Language Agent Navigation

arXiv.org Machine Learning

VALAN is a lightweight and scalable software framework for deep reinforcement learning based on the SEED RL architecture. The framework facilitates the development and evaluation of embodied agents for solving grounded language understanding tasks, such as Vision-and-Language Navigation and Vision-and-Dialog Navigation, in photo-realistic environments, such as Matterport3D and Google StreetView. We have added a minimal set of abstractions on top of SEED RL allowing us to generalize the architecture to solve a variety of other RL problems. In this article, we will describe VALAN's software abstraction and architecture, and also present an example of using VALAN to design agents for instruction-conditioned indoor navigation.


Making Smart Homes Smarter: Optimizing Energy Consumption with Human in the Loop

arXiv.org Artificial Intelligence

Rapid advancements in the Internet of Things (IoT) have facilitated more efficient deployment of smart environment solutions for specific user requirement. With the increase in the number of IoT devices, it has become difficult for the user to control or operate every individual smart device into achieving some desired goal like optimized power consumption, scheduled appliance running time, etc. Furthermore, existing solutions to automatically adapt the IoT devices are not capable enough to incorporate the user behavior. This paper presents a novel approach to accurately configure IoT devices while achieving the twin objectives of energy optimization along with conforming to user preferences. Our work comprises of unsupervised clustering of devices' data to find the states of operation for each device, followed by probabilistically analyzing user behavior to determine their preferred states. Eventually, we deploy an online reinforcement learning (RL) agent to find the best device settings automatically. Results for three different smart homes' data-sets show the effectiveness of our methodology. To the best of our knowledge, this is the first time that a practical approach has been adopted to achieve the above mentioned objectives without any human interaction within the system.


Does Knowledge Transfer Always Help to Learn a Better Policy?

arXiv.org Artificial Intelligence

One of the key approaches to save samples when learning a policy for a reinforcement learning problem is to use knowledge from an approximate model such as its simulator. However, does knowledge transfer from approximate models always help to learn a better policy? Despite numerous empirical studies of transfer reinforcement learning, an answer to this question is still elusive. In this paper, we provide a strong negative result, showing that even the full knowledge of an approximate model may not help reduce the number of samples for learning an accurate policy of the true model. We construct an example of reinforcement learning models and show that the complexity with or without knowledge transfer has the same order. On the bright side, effective knowledge transferring is still possible under additional assumptions. In particular, we demonstrate that knowing the (linear) bases of the true model significantly reduces the number of samples for learning an accurate policy.


RoboNet: A Dataset for Large-Scale Multi-Robot Learning

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Our goal is to pre-train reinforcement learning models on a diverse dataset and then transfer knowledge (either zero-shot or with fine-tuning) to a different test environment. In the last decade, we've seen learning-based systems provide transformative solutions for a wide range of perception and reasoning problems, from recognizing objects in images to recognizing and translating human speech. If fruitful, this line of work could allow learning-based systems to tackle active control tasks, such as robotics and autonomous driving, alongside the passive perception tasks to which they have already been successfully applied. While deep reinforcement learning methods – like Soft Actor Critic– can learn impressive motor skills, they are challenging to train on large and broad data that is not from the target environment. In contrast, the success of deep networks in fields like computer vision was arguably predicated just as much on large datasets, such as ImageNet, as on large neural network architectures.


Machine Learning

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The NICE Customer Engagement Analytics offers a best-of-breed machine learning system that can be deployed across multiple channels at enterprise scale to enable automated marketing decision-making for customers. Built on top of the NICE Customer Engagement Analytics core infrastructure including the identity graph and predictive profile, NICE utilizes breakthrough technology for reinforcement learning to deliver a scalable, reliable and robust decision engine.