Reinforcement Learning
Raising Student Completion Rates with Adaptive Curriculum and Contextual Bandits
Belfer, Robert, Kochmar, Ekaterina, Serban, Iulian Vlad
We present an adaptive learning Intelligent Tutoring System, which uses model-based reinforcement learning in the form of contextual bandits to assign learning activities to students. The model is trained on the trajectories of thousands of students in order to maximize their exercise completion rates and continues to learn online, automatically adjusting itself to new activities. A randomized controlled trial with students shows that our model leads to superior completion rates and significantly improved student engagement when compared to other approaches. Our approach is fully-automated unlocking new opportunities for learning experience personalization.
Inclined Quadrotor Landing using Deep Reinforcement Learning
Kooi, Jacob E., Babuška, Robert
Landing a quadrotor on an inclined surface is a challenging maneuver. The final state of any inclined landing trajectory is not an equilibrium, which precludes the use of most conventional control methods. We propose a deep reinforcement learning approach to design an autonomous landing controller for inclined surfaces. Using the proximal policy optimization (PPO) algorithm with sparse rewards and a tailored curriculum learning approach, an inclined landing policy can be trained in simulation in less than 90 minutes on a standard laptop. The policy then directly runs on a real Crazyflie 2.1 quadrotor and successfully performs real inclined landings in a flying arena. A single policy evaluation takes approximately 2.5\,ms, which makes it suitable for a future embedded implementation on the quadrotor.
Playing a 2D Game Indefinitely using NEAT and Reinforcement Learning
Selvan, Jerin Paul, Game, Pravin S.
For over a decade now, robotics and the use of artificial agents have become a common thing.Testing the performance of new path finding or search space optimization algorithms has also become a challenge as they require simulation or an environment to test them.The creation of artificial environments with artificial agents is one of the methods employed to test such algorithms.Games have also become an environment to test them.The performance of the algorithms can be compared by using artificial agents that will behave according to the algorithm in the environment they are put in.The performance parameters can be, how quickly the agent is able to differentiate between rewarding actions and hostile actions.This can be tested by placing the agent in an environment with different types of hurdles and the goal of the agent is to reach the farthest by taking decisions on actions that will lead to avoiding all the obstacles.The environment chosen is a game called "Flappy Bird".The goal of the game is to make the bird fly through a set of pipes of random heights.The bird must go in between these pipes and must not hit the top, the bottom, or the pipes themselves.The actions that the bird can take are either to flap its wings or drop down with gravity.The algorithms that are enforced on the artificial agents are NeuroEvolution of Augmenting Topologies (NEAT) and Reinforcement Learning.The NEAT algorithm takes an "N" initial population of artificial agents.They follow genetic algorithms by considering an objective function, crossover, mutation, and augmenting topologies.Reinforcement learning, on the other hand, remembers the state, the action taken at that state, and the reward received for the action taken using a single agent and a Deep Q-learning Network.The performance of the NEAT algorithm improves as the initial population of the artificial agents is increased.
Sony's Gran Turismo Sophy project wins the ACM SIGAI Industry Award
As part of a special industry session at IJCAI-ECAI 2022, the 2022 ACM SIGAI Industry Award for Excellence in Artificial Intelligence was presented to the team behind Sony's Gran Turismo Sophy project. This project was developed by Sony AI, Sony Interactive Entertainment and Polyphony Digital. Gran Turismo (GT) Sophy is a collection of agents trained using reinforcement learning (RL) techniques to race in Gran Turismo, a hyper-realistic, physics-based automotive racing simulator. The GT Sophy team developed novel, state-of-the-art RL methods for this purpose. Racing against some of the world's best e-sports drivers, GT Sophy has not only performed at world-class levels, it also won a team event in October 2021 by an impressive margin.
Reinforcement Learning
Reinforcement learning is the cherry on a great AI cake with Machine learning the cake itself and deep learning the icing. Without the previous iterations, the cherry would top nothing. Reinforcement learning (RL) is a kind of machine learning concerned with how intelligent agents take decisions in a dynamic environment in which it is supposed to perform a certain goal, so that the cumulative reward is maximized. The environment is the world that the agent lives in and interacts with. The agents are trained on a reward and punishment mechanism. The agent is rewarded for correct moves and punished for the wrong ones.
Reinforcement Learning and Stochastic Optimization: A Unified Framework for Sequential Decisions: Powell, Warren B.: 9781119815037: Amazon.com: Books
Warren B. Powell is Professor Emeritus at Princeton University, where he taught for 39 years, and is currently Chief Analytics Officer at Optimal Dynamics. He is the founder and director of CASTLE Labs, which developed models and algorithms in stochastic optimization, with applications to energy systems, transportation, health, e-commerce, and the laboratory sciences (see www.castlelab.princeton.edu). He has pioneered the use of approximate dynamic programming for high-dimensional applications, and the knowledge gradient for active learning problems. His recent work has focused on developing a unified framework for sequential decision problems under uncertainty, spanning active learning to a wide range of dynamic resource allocation problems. He has authored books on Approximate Dynamic Programming and (with Ilya Ryzhov) Optimal Learning, and is the author of Reinforcement Learning and Stochastic Optimization: A unified framework for sequential decisions.
Safe and Robust Experience Sharing for Deterministic Policy Gradient Algorithms
Saglam, Baturay, Cicek, Dogan C., Mutlu, Furkan B., Kozat, Suleyman S.
Learning in high dimensional continuous tasks is challenging, mainly when the experience replay memory is very limited. We introduce a simple yet effective experience sharing mechanism for deterministic policies in continuous action domains for the future off-policy deep reinforcement learning applications in which the allocated memory for the experience replay buffer is limited. To overcome the extrapolation error induced by learning from other agents' experiences, we facilitate our algorithm with a novel off-policy correction technique without any action probability estimates. We test the effectiveness of our method in challenging OpenAI Gym continuous control tasks and conclude that it can achieve a safe experience sharing across multiple agents and exhibits a robust performance when the replay memory is strictly limited.
Distributional Actor-Critic Ensemble for Uncertainty-Aware Continuous Control
Kanazawa, Takuya, Wang, Haiyan, Gupta, Chetan
Uncertainty quantification is one of the central challenges for machine learning in real-world applications. In reinforcement learning, an agent confronts two kinds of uncertainty, called epistemic uncertainty and aleatoric uncertainty. Disentangling and evaluating these uncertainties simultaneously stands a chance of improving the agent's final performance, accelerating training, and facilitating quality assurance after deployment. In this work, we propose an uncertainty-aware reinforcement learning algorithm for continuous control tasks that extends the Deep Deterministic Policy Gradient algorithm (DDPG). It exploits epistemic uncertainty to accelerate exploration and aleatoric uncertainty to learn a risk-sensitive policy. We conduct numerical experiments showing that our variant of DDPG outperforms vanilla DDPG without uncertainty estimation in benchmark tasks on robotic control and power-grid optimization.
Reinforcement Learning with Intrinsic Affinity for Personalized Prosperity Management
Maree, Charl, Omlin, Christian W.
Effective customer engagement is a requisite for modern financial service providers that are adopting advanced methods to increase the level of personalization of their services [1]. Although artificial intelligence (AI) has become a ubiquitous tool in financial technology [2], research in the field has yet to significantly advance levels of personalization [3]. Asset management is an active research topic in AI for finance; however, the research opportunities presented by the need for personalized services are usually neglected [4]. Whereas personalized investment advice is typically based on questionnaires, we propose the use of micro-segmentation based on spending behavior. Traditionally, customer segmentation has been grounded in demographics which provide only a coarse segmentation [5]; it fails to capture nuanced differences between individuals with the potential for undesirable ramifications, e.g.