Reinforcement Learning
Why Artificial Intelligence Should Be More Canadian
Canada has produced several big breakthroughs in artificial intelligence in recent years, and its government is keen to establish the country as a global epicenter of AI. The country's prime minister, Justin Trudeau, also hopes that the technology will learn Canadian values as it grows up. Speaking at a major AI event in Toronto today, Trudeau demonstrated an impressive enthusiasm for AI and machine learning, at one point even taking a stab at describing the concept of deep reinforcement learning, an approach that lets computers learn to do complex things that can't be programmed manually (see "10 Breakthrough Technologies 2017: Reinforcement Learning"). Both deep reinforcement learning and deep neural networks, which the method exploits, were pioneered by researchers working at Canadian universities. The country's government is now investing in big efforts to spur more AI research.
Transfer Learning to Learn with Multitask Neural Model Search
Wong, Catherine, Gesmundo, Andrea
Deep learning models require extensive architecture design exploration and hyperparameter optimization to perform well on a given task. The exploration of the model design space is often made by a human expert, and optimized using a combination of grid search and search heuristics over a large space of possible choices. Neural Architecture Search (NAS) is a Reinforcement Learning approach that has been proposed to automate architecture design. NAS has been successfully applied to generate Neural Networks that rival the best human-designed architectures. However, NAS requires sampling, constructing, and training hundreds to thousands of models to achieve well-performing architectures. This procedure needs to be executed from scratch for each new task. The application of NAS to a wide set of tasks currently lacks a way to transfer generalizable knowledge across tasks. In this paper, we present the Multitask Neural Model Search (MNMS) controller. Our goal is to learn a generalizable framework that can condition model construction on successful model searches for previously seen tasks, thus significantly speeding up the search for new tasks. We demonstrate that MNMS can conduct an automated architecture search for multiple tasks simultaneously while still learning well-performing, specialized models for each task. We then show that pre-trained MNMS controllers can transfer learning to new tasks. By leveraging knowledge from previous searches, we find that pre-trained MNMS models start from a better location in the search space and reduce search time on unseen tasks, while still discovering models that outperform published human-designed models.
Robust and Efficient Transfer Learning with Hidden-Parameter Markov Decision Processes
Killian, Taylor, Daulton, Samuel, Konidaris, George, Doshi-Velez, Finale
We introduce a new formulation of the Hidden Parameter Markov Decision Process (HiP-MDP), a framework for modeling families of related tasks using low-dimensional latent embeddings. Our new framework correctly models the joint uncertainty in the latent parameters and the state space. We also replace the original Gaussian Process-based model with a Bayesian Neural Network, enabling more scalable inference. Thus, we expand the scope of the HiP-MDP to applications with higher dimensions and more complex dynamics.
Reinforcement Learning for the Enterprise
This article is featured in the new DZone Guide to Artificial Intelligence. Get your free copy for more insightful articles, industry statistics, and more! Humanity has a unique ability to adapt to dynamic environments and learn from their surroundings and failures. It is something that machines lack, and that is where artificial intelligence seeks to correct this deficiency. However, traditional supervised machine learning techniques require a lot of proper historical data to learn patterns and then act based on them.
C. Karen Liu: Modeling Human Movements for Robotics CMU RI Seminar
Abstract: "Creating realistic virtual humans has traditionally been considered a research problem in Computer Animation primarily for entertainment applications. With the recent breakthrough in collaborative robots and deep reinforcement learning, accurately modeling human movements and behaviors has become a common challenge faced by researchers in robotics, artificial intelligence, as well as Computer Animation. In this talk, I will focus on two different yet highly relevant problems: how to teach robots to move like humans and how to teach robots to interact with humans. While Computer Animation research has shown that it is possible to teach a virtual human to mimic human athletes' movements, transferring such complex controllers to robot hardware in the real world is perhaps even more challenging than learning the controllers themselves. In this talk, I will focus on two strategies to transfer highly dynamic skills from character animation to robots: teaching robots basic self-preservation motor skills and developing data-driven algorithms on transfer learning between simulation and the real world. The second part of the talk will focus on robotic assistance with dressing, which is a prominent activities of daily living (ADLs) most commonly requested by older adults. To safely train a robot to physically interact with humans, one can design a generative model of human motion based on prior knowledge or recorded motion data. Although this approach has been successful in Computer Animation, such as generating locomotion, designing procedures for a loosely defined task, such as "being dressed", is likely to be biased to the specific data or assumptions. I will describe a new approach to modeling human motion without being biased toward specific situations presented in the dataset."
Reinforcement Learning Coach by Intel - Intel Nervana
Gal is a research engineer at the Intel Nervana algorithms team. He has a great passion for AI, and specifically for training and implementing Reinforcement Learning agents. He has optimized and trained low precision neural networks, enabling deep learning inference, on various Intel devices. He has been with Intel for 10 years, and before joining Intel Nervana, was mainly focused on power management algorithms optimization for Intel CPUs. In his spare time, Gal enjoys baking sourdough breads, hiking and watching movies with his wife.
Distributional Reinforcement Learning with Quantile Regression
Dabney, Will, Rowland, Mark, Bellemare, Marc G., Munos, Rรฉmi
In reinforcement learning an agent interacts with the environment by taking actions and observing the next state and reward. When sampled probabilistically, these state transitions, rewards, and actions can all induce randomness in the observed long-term return. Traditionally, reinforcement learning algorithms average over this randomness to estimate the value function. In this paper, we build on recent work advocating a distributional approach to reinforcement learning in which the distribution over returns is modeled explicitly instead of only estimating the mean. That is, we examine methods of learning the value distribution instead of the value function. We give results that close a number of gaps between the theoretical and algorithmic results given by Bellemare, Dabney, and Munos (2017). First, we extend existing results to the approximate distribution setting. Second, we present a novel distributional reinforcement learning algorithm consistent with our theoretical formulation. Finally, we evaluate this new algorithm on the Atari 2600 games, observing that it significantly outperforms many of the recent improvements on DQN, including the related distributional algorithm C51.
Will scikit-learn utilize GPU?
By default none of both are going to use GPU, especially if it is running inside Docker, unless you use nvidia-docker and an image capable of doing it. Scikit-learn is not intended to be used as a deep-learning framework, and seems that it doesn't support GPU computations. Why is there no support for deep or reinforcement learning / Will there be support for deep or reinforcement learning in scikit-learn? Deep learning and reinforcement learning both require a rich vocabulary to define an architecture, with deep learning additionally requiring GPUs for efficient computing. However, neither of these fit within the design constraints of scikit-learn; as a result, deep learning and reinforcement learning are currently out of scope for what scikit-learn seeks to achieve.
Reinforcement Learning and AI
Summary: At the core of modern AI, particularly robotics, and sequential tasks is Reinforcement Learning. Although RL has been around for many years it has become the third leg of the Machine Learning stool and increasingly important for Data Scientist to know when and how to implement. If you poled a group of data scientist just a few years back about how many machine learning problem types there are you would almost certainly have gotten a binary response: problem types were clearly divided into supervised and unsupervised. While Reinforcement Learning (RL) has been around since at least the 80's and before that in the behavioral sciences, its introduction as a major player in machine learning reflects it rising importance in AI. What problems fit this description?
Exploiting generalization in the subspaces for faster model-based learning
Hashemzadeh, Maryam, Hosseini, Reshad, Ahmadabadi, Majid Nili
Due to the lack of enough generalization in the state-space, common methods in Reinforcement Learning (RL) suffer from slow learning speed especially in the early learning trials. This paper introduces a model-based method in discrete state-spaces for increasing learning speed in terms of required experience (but not required computational time) by exploiting generalization in the experiences of the subspaces. A subspace is formed by choosing a subset of features in the original state representation (full-space). Generalization and faster learning in a subspace are due to many-to-one mapping of experiences from the full-space to each state in the subspace. Nevertheless, due to inherent perceptual aliasing in the subspaces, the policy suggested by each subspace does not generally converge to the optimal policy. Our approach, called Model Based Learning with Subspaces (MoBLeS), calculates confidence intervals of the estimated Q-values in the full-space and in the subspaces. These confidence intervals are used in the decision making, such that the agent benefits the most from the possible generalization while avoiding from detriment of the perceptual aliasing in the subspaces. Convergence of MoBLeS to the optimal policy is theoretically investigated. Additionally, we show through several experiments that MoBLeS improves the learning speed in the early trials.