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 Reinforcement Learning


Meta-Reinforcement Learning for Trajectory Design in Wireless UAV Networks

arXiv.org Machine Learning

In this paper, the design of an optimal trajectory for an energy-constrained drone operating in dynamic network environments is studied. In the considered model, a drone base station (DBS) is dispatched to provide uplink connectivity to ground users whose demand is dynamic and unpredictable. In this case, the DBS's trajectory must be adaptively adjusted to satisfy the dynamic user access requests. To this end, a meta-learning algorithm is proposed in order to adapt the DBS's trajectory when it encounters novel environments, by tuning a reinforcement learning (RL) solution. The meta-learning algorithm provides a solution that adapts the DBS in novel environments quickly based on limited former experiences. The meta-tuned RL is shown to yield a faster convergence to the optimal coverage in unseen environments with a considerably low computation complexity, compared to the baseline policy gradient algorithm. Simulation results show that, the proposed meta-learning solution yields a 25% improvement in the convergence speed, and about 10% improvement in the DBS' communication performance, compared to a baseline policy gradient algorithm. Meanwhile, the probability that the DBS serves over 50% of user requests increases about 27%, compared to the baseline policy gradient algorithm.


Generator and Critic: A Deep Reinforcement Learning Approach for Slate Re-ranking in E-commerce

arXiv.org Machine Learning

The slate re-ranking problem considers the mutual influences between items to improve user satisfaction in e-commerce, compared with the point-wise ranking. Previous works either directly rank items by an end to end model, or rank items by a score function that trades-off the point-wise score and the diversity between items. However, there are two main existing challenges that are not well studied: (1) the evaluation of the slate is hard due to the complex mutual influences between items of one slate; (2) even given the optimal evaluation, searching the optimal slate is challenging as the action space is exponentially large. In this paper, we present a novel Generator and Critic slate re-ranking approach, where the Critic evaluates the slate and the Generator ranks the items by the reinforcement learning approach. We propose a Full Slate Critic (FSC) model that considers the real impressed items and avoids the "impressed bias" of existing models. For the Generator, to tackle the Figure 1: The return list when searching "smart watch" problem of large action space, we propose a new exploration reinforcement learning algorithm, called PPO-Exploration. Experimental results show that the FSC model significantly outperforms the state of the art slate evaluation methods, and the PPO-Exploration To improve the diversity of the list, a series of research works, algorithm outperforms the existing reinforcement learning methods MMR, IA-Select, xQuAD and DUM [1, 4, 9, 24] are proposed to rank substantially. The Generator and Critic approach improves both items by weighted functions that tradeoff the user-item scores and the slate efficiency(4% gmv and 5% number of orders) and diversity the diversities of items. However, these methods ignore the impact in live experiments on one of the largest e-commerce websites in of diversity on the efficiency of the list.


Gradient Monitored Reinforcement Learning

arXiv.org Machine Learning

This paper presents a novel neural network training approach for faster convergence and better generalization abilities in deep reinforcement learning. Particularly, we focus on the enhancement of training and evaluation performance in reinforcement learning algorithms by systematically reducing gradient's variance and thereby providing a more targeted learning process. The proposed method which we term as Gradient Monitoring(GM), is an approach to steer the learning in the weight parameters of a neural network based on the dynamic development and feedback from the training process itself. We propose different variants of the GM methodology which have been proven to increase the underlying performance of the model. The one of the proposed variant, Momentum with Gradient Monitoring (M-WGM), allows for a continuous adjustment of the quantum of back-propagated gradients in the network based on certain learning parameters. We further enhance the method with Adaptive Momentum with Gradient Monitoring (AM-WGM) method which allows for automatic adjustment between focused learning of certain weights versus a more dispersed learning depending on the feedback from the rewards collected. As a by-product, it also allows for automatic derivation of the required deep network sizes during training as the algorithm automatically freezes trained weights. The approach is applied to two discrete (Multi-Robot Co-ordination problem and Atari games) and one continuous control task (MuJoCo) using Advantage Actor-Critic (A2C) and Proximal Policy Optimization (PPO) respectively. The results obtained particularly underline the applicability and performance improvements of the methods in terms of generalization capability.


Learning visual servo policies via planner cloning

arXiv.org Artificial Intelligence

This algorithm differs from Visual servoing in novel environments is an important AGGREVATE because problem. Given images produced by a camera, a visual servo it incorporates the value control policy guides a grasped part into a desired pose penalties and from DQfD relative to the environment. This problem appears in many because it uses supervised situations: reaching, grasping, peg insertion, stacking, machine targets rather than TD assembly tasks, etc. Whereas classical approaches to the targets. We compare PQC problem [6, 3, 27] typically make strong assumptions about the with several baselines and environment (fiducials, known object geometries, etc.), there algorithm ablations and has been a surge of interest recently in using deep learning show that it outperforms methods to solve these problems in more unstructured settings all these variations on two that incorporate novel objects [29, 14, 26, 8, 21, 28, 12, 13].


Automatic Discovery of Interpretable Planning Strategies

arXiv.org Artificial Intelligence

When making decisions, people often overlook critical information or are overly swayed by irrelevant information. A common approach to mitigate these biases is to provide decision-makers, especially professionals such as medical doctors, with decision aids, such as decision trees and flowcharts. Designing effective decision aids is a difficult problem. We propose that recently developed reinforcement learning methods for discovering clever heuristics for good decision-making can be partially leveraged to assist human experts in this design process. One of the biggest remaining obstacles to leveraging the aforementioned methods for improving human decision-making is that the policies they learn are opaque to people. To solve this problem, we introduce AI-Interpret: a general method for transforming idiosyncratic policies into simple and interpretable descriptions. Our algorithm combines recent advances in imitation learning and program induction with a new clustering method for identifying a large subset of demonstrations that can be accurately described by a simple, high-performing decision rule. We evaluate our new AI-Interpret algorithm and employ it to translate information-acquisition policies discovered through metalevel reinforcement learning. The results of three large behavioral experiments showed that the provision of decision rules as flowcharts significantly improved people's planning strategies and decisions across three different classes of sequential decision problems. Furthermore, a series of ablation studies confirmed that our AI-Interpret algorithm was critical to the discovery of interpretable decision rules and that it is ready to be applied to other reinforcement learning problems. We conclude that the methods and findings presented in this article are an important step towards leveraging automatic strategy discovery to improve human decision-making.


Reinforcement Learning with Iterative Reasoning for Merging in Dense Traffic

arXiv.org Artificial Intelligence

To avoid the computational requirements of online methods, we can use reinforcement learning (RL) instead. In RL, In recent years, major progress has been made to deploy the agent interacts with a simulation environment many autonomous vehicles and improve safety. However, certain times prior to execution, and at each simulation episode common driving situations like merging in dense traffic are it improves its strategy. The resulting policy can then be still challenging for autonomous vehicles. Situations like deployed online and is often inexpensive to evaluate. RL the one illustrated in Figure 1 often involve negotiating with provides a flexible framework to automatically find good human drivers.


Machine Learning Tutorial Part 1 Machine Learning For Beginners

#artificialintelligence

Sign in to report inappropriate content. This Machine Learning tutorial will introduce you to the different areas of Machine Learning and Artificial Intelligence. In this part of the course you will learn about the three different learning types (Unsupervised learning, Supervised Learning and Reinforcement Learning) For more see: https://www.Vinsloev.com Remember to Subscribe to the channel to see the upcoming parts of this Tutorial as well.



Evaluating Generalisation in General Video Game Playing

arXiv.org Artificial Intelligence

The General Video Game Artificial Intelligence (GVGAI) competition has been running for several years with various tracks. This paper focuses on the challenge of the GVGAI learning track in which 3 games are selected and 2 levels are given for training, while 3 hidden levels are left for evaluation. This setup poses a difficult challenge for current Reinforcement Learning (RL) algorithms, as they typically require much more data. This work investigates 3 versions of the Advantage Actor-Critic (A2C) algorithm trained on a maximum of 2 levels from the available 5 from the GVGAI framework and compares their performance on all levels. The selected sub-set of games have different characteristics, like stochasticity, reward distribution and objectives. We found that stochasticity improves the generalisation, but too much can cause the algorithms to fail to learn the training levels. The quality of the training levels also matters, different sets of training levels can boost generalisation over all levels. In the GVGAI competition agents are scored based on their win rates and then their scores achieved in the games. We found that solely using the rewards provided by the game might not encourage winning.


Reinforcement learning with human advice. A survey

arXiv.org Artificial Intelligence

In this paper, we provide an overview of the existing methods for integrating human advice into a Reinforcement Learning process. We propose a taxonomy of different types of teaching signals, and present them according to three main aspects: how they can be provided to the learning agent, how they can be integrated into the learning process, and how they can be interpreted by the agent if their meaning is not determined beforehand. Finally, we compare the benefits and limitations of using each type of teaching signals, and propose a unified view of interactive learning methods.