Reinforcement Learning
One for Many: Transfer Learning for Building HVAC Control
Xu, Shichao, Wang, Yixuan, Wang, Yanzhi, O'Neill, Zheng, Zhu, Qi
The design of building heating, ventilation, and air conditioning (HVAC) system is critically important, as it accounts for around half of building energy consumption and directly affects occupant comfort, productivity, and health. Traditional HVAC control methods are typically based on creating explicit physical models for building thermal dynamics, which often require significant effort to develop and are difficult to achieve sufficient accuracy and efficiency for runtime building control and scalability for field implementations. Recently, deep reinforcement learning (DRL) has emerged as a promising data-driven method that provides good control performance without analyzing physical models at runtime. However, a major challenge to DRL (and many other data-driven learning methods) is the long training time it takes to reach the desired performance. In this work, we present a novel transfer learning based approach to overcome this challenge. Our approach can effectively transfer a DRL-based HVAC controller trained for the source building to a controller for the target building with minimal effort and improved performance, by decomposing the design of neural network controller into a transferable front-end network that captures building-agnostic behavior and a back-end network that can be efficiently trained for each specific building. We conducted experiments on a variety of transfer scenarios between buildings with different sizes, numbers of thermal zones, materials and layouts, air conditioner types, and ambient weather conditions. The experimental results demonstrated the effectiveness of our approach in significantly reducing the training time, energy cost, and temperature violations.
Non-Adversarial Imitation Learning and its Connections to Adversarial Methods
Imitation learning (IL, Schaal, 1999; Osa et al., 2018) and inverse reinforcement learning (IRL, Ng and Russell, 2000) are two related areas of research that aim to teach agents by providing demonstrations of the desired behavior. Whereas imitation learning aims to learn a policy that results in a similar behavior, inverse reinforcement learning focuses on inferring a reward function that might have been optimized by the demonstrator, aiming to better generalize to different environments. Both areas of research are often formalized as distribution-matching, that is, the learned policy (or the optimal policy for IRL) should induce a distribution over states and actions that is close to the expert's distribution with respect to a given (usually non-metric) distance. Commonly applied distances are the forward Kullback-Leibler (KL) divergence (e.g., Ziebart, 2010), which maximizes the likelihood of the demonstrated state-action pairs under the agent's distribution, and the reverse Kullback-Leibler (RKL) divergence (e.g., Arenz et al., 2016; Fu et al., 2018; Ghasemipour et al., 2020) which minimizes the expected discrimination information (Kullback and Leibler, 1951) of state-action pairs sampled from the agent's distribution. However, since the emergence of generative adversarial networks (GANs, Goodfellow et al., 2014) as a solution technique for both areas, other divergences have been investigated such as the Jensen-Shannon divergence (Ho and Ermon, 2016), the Wasserstein distance (Xiao et al., 2019) and general f-divergences (Ke et al., 2019; Ghasemipour et al., 2020).
Artificial Intelligence Masterclass
Online Courses Udemy - Artificial Intelligence Masterclass, Enter the new era of Hybrid AI Models optimized by Deep NeuroEvolution, with a complete toolkit of ML, DL & AI models Created by Hadelin de Ponteves, Kirill Eremenko, SuperDataScience Team English, Italian [Auto] Students also bought Deep Reinforcement Learning 2.0 Cutting-Edge AI: Deep Reinforcement Learning in Python Artificial Intelligence for Business Deep Learning: Advanced Computer Vision (GANs, SSD, More!) Deep Learning: Convolutional Neural Networks in Python TensorFlow 2.0 Practical Advanced Preview this course GET COUPON CODE Description Today, we are bringing you the king of our AI courses...: The Artificial Intelligence MASTERCLASS Are you keen on Artificial Intelligence? Do want to learn to build the most powerful AI model developed so far and even play against it? Sounds tempting right... Then Artificial Intelligence Masterclass course is the right choice for you. This ultimate AI toolbox is all you need to nail it down with ease. You will get 10 hours step by step guide and the full roadmap which will help you build your own Hybrid AI Model from scratch.
Markov Decision Process
A machine learning algorithm may be tasked with an optimization problem. Using reinforcement learning, the algorithm will attempt to optimize the actions taken within an environment, in order to maximize the potential reward. Where supervised learning techniques require correct input/output pairs to create a model, reinforcement learning uses Markov decision processes to determine an optimal balance of exploration and exploitation. Machine learning may use reinforcement learning by way of the Markov decision process when the probabilities and rewards of an outcome are unspecified or unknown.
Managing caching strategies for stream reasoning with reinforcement learning
Dodaro, Carmine, Eiter, Thomas, Ogris, Paul, Schekotihin, Konstantin
Efficient decision-making over continuously changing data is essential for many application domains such as cyber-physical systems, industry digitalization, etc. Modern stream reasoning frameworks allow one to model and solve various real-world problems using incremental and continuous evaluation of programs as new data arrives in the stream. Applied techniques use, e.g., Datalog-like materialization or truth maintenance algorithms to avoid costly re-computations, thus ensuring low latency and high throughput of a stream reasoner. However, the expressiveness of existing approaches is quite limited and, e.g., they cannot be used to encode problems with constraints, which often appear in practice. In this paper, we suggest a novel approach that uses the Conflict-Driven Constraint Learning (CDCL) to efficiently update legacy solutions by using intelligent management of learned constraints. In particular, we study the applicability of reinforcement learning to continuously assess the utility of learned constraints computed in previous invocations of the solving algorithm for the current one. Evaluations conducted on real-world reconfiguration problems show that providing a CDCL algorithm with relevant learned constraints from previous iterations results in significant performance improvements of the algorithm in stream reasoning scenarios.
SafePILCO: a software tool for safe and data-efficient policy synthesis
Polymenakos, Kyriakos, Rontsis, Nikitas, Abate, Alessandro, Roberts, Stephen
SafePILCO is a software tool for safe and data-efficient policy search with reinforcement learning. It extends the known PILCO algorithm, originally written in MATLAB, to support safe learning. We provide a Python implementation and leverage existing libraries that allow the codebase to remain short and modular, which is appropriate for wider use by the verification, reinforcement learning, and control communities.
Distributed Deep Reinforcement Learning for Functional Split Control in Energy Harvesting Virtualized Small Cells
Temesgene, Dagnachew Azene, Miozzo, Marco, Gündüz, Deniz, Dini, Paolo
To meet the growing quest for enhanced network capacity, mobile network operators (MNOs) are deploying dense infrastructures of small cells. This, in turn, increases the power consumption of mobile networks, thus impacting the environment. As a result, we have seen a recent trend of powering mobile networks with harvested ambient energy to achieve both environmental and cost benefits. In this paper, we consider a network of virtualized small cells (vSCs) powered by energy harvesters and equipped with rechargeable batteries, which can opportunistically offload baseband (BB) functions to a grid-connected edge server depending on their energy availability. We formulate the corresponding grid energy and traffic drop rate minimization problem, and propose a distributed deep reinforcement learning (DDRL) solution. Coordination among vSCs is enabled via the exchange of battery state information. The evaluation of the network performance in terms of grid energy consumption and traffic drop rate confirms that enabling coordination among the vSCs via knowledge exchange achieves a performance close to the optimal. Numerical results also confirm that the proposed DDRL solution provides higher network performance, better adaptation to the changing environment, and higher cost savings with respect to a tabular multi-agent reinforcement learning (MRL) solution used as a benchmark.
Offline Meta Reinforcement Learning
Consider the following problem, which we term Offline Meta Reinforcement Learning (OMRL): given the complete training histories of $N$ conventional RL agents, trained on $N$ different tasks, design a learning agent that can quickly maximize reward in a new, unseen task from the same task distribution. In particular, while each conventional RL agent explored and exploited its own different task, the OMRL agent must identify regularities in the data that lead to effective exploration/exploitation in the unseen task. To solve OMRL, we take a Bayesian RL (BRL) view, and seek to learn a Bayes-optimal policy from the offline data. We extend the recently proposed VariBAD BRL algorithm to the off-policy setting, and demonstrate learning of Bayes-optimal exploration strategies from offline data using deep neural networks. Furthermore, when applied to the online meta-RL setting (agent simultaneously collects data and improves its meta-RL policy), our method is significantly more sample efficient than the conventional VariBAD.
Towards General and Autonomous Learning of Core Skills: A Case Study in Locomotion
Hafner, Roland, Hertweck, Tim, Klöppner, Philipp, Bloesch, Michael, Neunert, Michael, Wulfmeier, Markus, Tunyasuvunakool, Saran, Heess, Nicolas, Riedmiller, Martin
Modern Reinforcement Learning (RL) algorithms promise to solve difficult motor control problems directly from raw sensory inputs. Their attraction is due in part to the fact that they can represent a general class of methods that allow to learn a solution with a reasonably set reward and minimal prior knowledge, even in situations where it is difficult or expensive for a human expert. For RL to truly make good on this promise, however, we need algorithms and learning setups that can work across a broad range of problems with minimal problem specific adjustments or engineering. In this paper, we study this idea of generality in the locomotion domain. We develop a learning framework that can learn sophisticated locomotion behavior for a wide spectrum of legged robots, such as bipeds, tripeds, quadrupeds and hexapods, including wheeled variants. Our learning framework relies on a data-efficient, off-policy multi-task RL algorithm and a small set of reward functions that are semantically identical across robots. To underline the general applicability of the method, we keep the hyper-parameter settings and reward definitions constant across experiments and rely exclusively on on-board sensing. For nine different types of robots, including a real-world quadruped robot, we demonstrate that the same algorithm can rapidly learn diverse and reusable locomotion skills without any platform specific adjustments or additional instrumentation of the learning setup.