从人类反馈中进行交互学习的能力将使代理在新环境中。例如，即使是新手用户也可以自然和互动地培训服务机器人。人类在循环增强学习（HRL）结合了人类的反馈和增强学习（RL）技术。最先进的互动学习技术遭受缓慢的学习速度，因此导致了人类的沮丧经历。我们通过扩展HRL框架TAMER来评估反馈来解决此问题，并有可能通过两种不同类型的反事实解释（基于动作和状态）来增强人类反馈。我们通过实验表明，我们的扩展提高了学习速度。

Adequately assigning credit to actions for future outcomes based on their contributions is a long-standing open challenge in Reinforcement Learning. The assumptions of the most commonly used credit assignment method are disadvantageous in tasks where the effects of decisions are not immediately evident. Furthermore, this method can only evaluate actions that have been selected by the agent, making it highly inefficient. Still, no alternative methods have been widely adopted in the field. Hindsight Credit Assignment is a promising, but still unexplored candidate, which aims to solve the problems of both long-term and counterfactual credit assignment. In this thesis, we empirically investigate Hindsight Credit Assignment to identify its main benefits, and key points to improve. Then, we apply it to factored state representations, and in particular to state representations based on the causal structure of the environment. In this setting, we propose a variant of Hindsight Credit Assignment that effectively exploits a given causal structure. We show that our modification greatly decreases the workload of Hindsight Credit Assignment, making it more efficient and enabling it to outperform the baseline credit assignment method on various tasks. This opens the way to other methods based on given or learned causal structures.

强化学习（RL）和脑电脑接口（BCI）是过去十年一直在增长的两个领域。直到最近，这些字段彼此独立操作。随着对循环（HITL）应用的兴趣升高，RL算法已经适用于人类指导，从而产生互动强化学习（IRL）的子领域。相邻的，BCI应用一直很感兴趣在人机交互期间从神经活动中提取内在反馈。这两个想法通过将BCI集成到IRL框架中，将RL和BCI设置在碰撞过程中，通过将内在反馈可用于帮助培训代理商来帮助框架。这种交叉点被称为内在的IRL。为了进一步帮助，促进BCI和IRL的更深层次，我们对内在IRILL的审查有着重点在于其母体领域的反馈驱动的IRL，同时还提供有关有效性，挑战和未来研究方向的讨论。

The reinforcement learning paradigm is a popular way to address problems that have only limited environmental feedback, rather than correctly labeled examples, as is common in other machine learning contexts. While significant progress has been made to improve learning in a single task, the idea of transfer learning has only recently been applied to reinforcement learning tasks. The core idea of transfer is that experience gained in learning to perform one task can help improve learning performance in a related, but different, task. In this article we present a framework that classifies transfer learning methods in terms of their capabilities and goals, and then use it to survey the existing literature, as well as to suggest future directions for transfer learning work.

在过去的十年中，多智能经纪人强化学习（Marl）已经有了重大进展，但仍存在许多挑战，例如高样本复杂性和慢趋同稳定的政策，在广泛的部署之前需要克服，这是可能的。然而，在实践中，许多现实世界的环境已经部署了用于生成策略的次优或启发式方法。一个有趣的问题是如何最好地使用这些方法作为顾问，以帮助改善多代理领域的加强学习。在本文中，我们提供了一个原则的框架，用于将动作建议纳入多代理设置中的在线次优顾问。我们描述了在非传记通用随机游戏环境中提供多种智能强化代理（海军上将）的问题，并提出了两种新的基于Q学习的算法：海军上将决策（海军DM）和海军上将 - 顾问评估（Admiral-AE） ，这使我们能够通过适当地纳入顾问（Admiral-DM）的建议来改善学习，并评估顾问（Admiral-AE）的有效性。我们从理论上分析了算法，并在一般加上随机游戏中提供了关于他们学习的定点保证。此外，广泛的实验说明了这些算法：可以在各种环境中使用，具有对其他相关基线的有利相比的性能，可以扩展到大状态行动空间，并且对来自顾问的不良建议具有稳健性。

深度加强学习（DEEPRL）方法已广泛用于机器人学，以了解环境，自主获取行为。深度互动强化学习（Deepirl）包括来自外部培训师或专家的互动反馈，提供建议，帮助学习者选择采取行动以加快学习过程。但是，目前的研究仅限于仅为特工现任提供可操作建议的互动。另外，在单个使用之后，代理丢弃该信息，该用途在为Revisit以相同状态引起重复过程。在本文中，我们提出了广泛的建议（BPA），这是一种广泛的持久的咨询方法，可以保留并重新使用加工信息。它不仅可以帮助培训师提供与类似状态相关的更一般性建议，而不是仅仅是当前状态，而且还允许代理加快学习过程。我们在两个连续机器人场景中测试提出的方法，即购物车极衡任务和模拟机器人导航任务。所得结果表明，使用BPA的代理的性能在于与深层方法相比保持培训师所需的相互作用的数量。

With the development of deep representation learning, the domain of reinforcement learning (RL) has become a powerful learning framework now capable of learning complex policies in high dimensional environments. This review summarises deep reinforcement learning (DRL) algorithms and provides a taxonomy of automated driving tasks where (D)RL methods have been employed, while addressing key computational challenges in real world deployment of autonomous driving agents. It also delineates adjacent domains such as behavior cloning, imitation learning, inverse reinforcement learning that are related but are not classical RL algorithms. The role of simulators in training agents, methods to validate, test and robustify existing solutions in RL are discussed.

Safe Reinforcement Learning can be defined as the process of learning policies that maximize the expectation of the return in problems in which it is important to ensure reasonable system performance and/or respect safety constraints during the learning and/or deployment processes. We categorize and analyze two approaches of Safe Reinforcement Learning. The first is based on the modification of the optimality criterion, the classic discounted finite/infinite horizon, with a safety factor. The second is based on the modification of the exploration process through the incorporation of external knowledge or the guidance of a risk metric. We use the proposed classification to survey the existing literature, as well as suggesting future directions for Safe Reinforcement Learning.

Transformer, originally devised for natural language processing, has also attested significant success in computer vision. Thanks to its super expressive power, researchers are investigating ways to deploy transformers to reinforcement learning (RL) and the transformer-based models have manifested their potential in representative RL benchmarks. In this paper, we collect and dissect recent advances on transforming RL by transformer (transformer-based RL or TRL), in order to explore its development trajectory and future trend. We group existing developments in two categories: architecture enhancement and trajectory optimization, and examine the main applications of TRL in robotic manipulation, text-based games, navigation and autonomous driving. For architecture enhancement, these methods consider how to apply the powerful transformer structure to RL problems under the traditional RL framework, which model agents and environments much more precisely than deep RL methods, but they are still limited by the inherent defects of traditional RL algorithms, such as bootstrapping and "deadly triad". For trajectory optimization, these methods treat RL problems as sequence modeling and train a joint state-action model over entire trajectories under the behavior cloning framework, which are able to extract policies from static datasets and fully use the long-sequence modeling capability of the transformer. Given these advancements, extensions and challenges in TRL are reviewed and proposals about future direction are discussed. We hope that this survey can provide a detailed introduction to TRL and motivate future research in this rapidly developing field.

深度强化学习（RL）导致了许多最近和开创性的进步。但是，这些进步通常以培训的基础体系结构的规模增加以及用于训练它们的RL算法的复杂性提高，而均以增加规模的成本。这些增长反过来又使研究人员更难迅速原型新想法或复制已发表的RL算法。为了解决这些问题，这项工作描述了ACME，这是一个用于构建新型RL算法的框架，这些框架是专门设计的，用于启用使用简单的模块化组件构建的代理，这些组件可以在各种执行范围内使用。尽管ACME的主要目标是为算法开发提供一个框架，但第二个目标是提供重要或最先进算法的简单参考实现。这些实现既是对我们的设计决策的验证，也是对RL研究中可重复性的重要贡献。在这项工作中，我们描述了ACME内部做出的主要设计决策，并提供了有关如何使用其组件来实施各种算法的进一步详细信息。我们的实验为许多常见和最先进的算法提供了基准，并显示了如何为更大且更复杂的环境扩展这些算法。这突出了ACME的主要优点之一，即它可用于实现大型，分布式的RL算法，这些算法可以以较大的尺度运行，同时仍保持该实现的固有可读性。这项工作提出了第二篇文章的版本，恰好与模块化的增加相吻合，对离线，模仿和从演示算法学习以及作为ACME的一部分实现的各种新代理。

Deep reinforcement learning is poised to revolutionise the field of AI and represents a step towards building autonomous systems with a higher level understanding of the visual world. Currently, deep learning is enabling reinforcement learning to scale to problems that were previously intractable, such as learning to play video games directly from pixels. Deep reinforcement learning algorithms are also applied to robotics, allowing control policies for robots to be learned directly from camera inputs in the real world. In this survey, we begin with an introduction to the general field of reinforcement learning, then progress to the main streams of value-based and policybased methods. Our survey will cover central algorithms in deep reinforcement learning, including the deep Q-network, trust region policy optimisation, and asynchronous advantage actor-critic. In parallel, we highlight the unique advantages of deep neural networks, focusing on visual understanding via reinforcement learning. To conclude, we describe several current areas of research within the field.

多机构增强学习（MARL）已成为解决分散决策问题的有用方法。近年来提出的许多突破性算法一直在稳步增长。在这项工作中，我们仔细研究了这一快速发展，重点是在合作Marl的大量研究中采用的评估方法。通过对先前工作进行详细的荟萃分析，涵盖了从2016年至2022年接受出版的75篇论文，我们引起了人们对真正进步率的质疑的令人担忧的趋势。我们在更广泛的背景下进一步考虑了这些趋势，并从单一AGENT RL文献中获得了有关类似问题的灵感，这些建议以及仍然适用于MARL的建议。将这些建议与我们分析的新见解相结合，我们提出了合作MARL的标准化绩效评估方案。我们认为，这样的标准协议，如果被广泛采用，将大大提高未来研究的有效性和信誉，使复制和可重复性更加容易，并提高该领域的能力，通过能够通过能够准确评估进度的速度进行跨不同作品的合理比较。最后，我们在我们的项目网站上公开发布荟萃分析数据，以供未来的评估研究：https：//sites.google.com/view/marl-andard-protocol

交互式增强学习建议使用外部信息，以加快学习过程。当与学习者互动时，人类可以提供评估或有益的建议。先前的研究通过在交互式增强学习过程中包括实时反馈，专门旨在提高代理商的学习速度，同时最大程度地减少对人类的时间的需求，从而重点关注人类建议的效果。这项工作重点是回答两种评估或信息性的方法中的哪种是人类的首选教学方法。此外，这项工作为人类试验提供了实验设置，旨在比较人们用来提供人类参与建议的方法。获得的结果表明，向学习者提供信息的用户提供了更准确的建议，愿意在更长的时间内为学习者提供帮助，并每集提供更多建议。此外，使用信息丰富的方法的参与者的自我评估表明，与提供评估建议的人相比，代理商遵循建议的能力更高，因此，他们认为自己的建议的准确性更高。

Reinforcement Learning (RL) is a popular machine learning paradigm where intelligent agents interact with the environment to fulfill a long-term goal. Driven by the resurgence of deep learning, Deep RL (DRL) has witnessed great success over a wide spectrum of complex control tasks. Despite the encouraging results achieved, the deep neural network-based backbone is widely deemed as a black box that impedes practitioners to trust and employ trained agents in realistic scenarios where high security and reliability are essential. To alleviate this issue, a large volume of literature devoted to shedding light on the inner workings of the intelligent agents has been proposed, by constructing intrinsic interpretability or post-hoc explainability. In this survey, we provide a comprehensive review of existing works on eXplainable RL (XRL) and introduce a new taxonomy where prior works are clearly categorized into model-explaining, reward-explaining, state-explaining, and task-explaining methods. We also review and highlight RL methods that conversely leverage human knowledge to promote learning efficiency and performance of agents while this kind of method is often ignored in XRL field. Some challenges and opportunities in XRL are discussed. This survey intends to provide a high-level summarization of XRL and to motivate future research on more effective XRL solutions. Corresponding open source codes are collected and categorized at https://github.com/Plankson/awesome-explainable-reinforcement-learning.

在合作多智能体增强学习（Marl）中的代理商的创造和破坏是一个批判性的研究领域。当前的Marl算法通常认为，在整个实验中，组内的代理数量仍然是固定的。但是，在许多实际问题中，代理人可以在队友之前终止。这次早期终止问题呈现出挑战：终止的代理人必须从本集团的成功或失败中学习，这是超出其自身存在的成败。我们指代薪资奖励的传播价值作为遣返代理商作为追索的奖励作为追索权。当前的MARL方法通过将这些药剂放在吸收状态下，直到整组试剂达到终止条件，通过将这些药剂置于终止状态来处理该问题。虽然吸收状态使现有的算法和API能够在没有修改的情况下处理终止的代理，但存在实际培训效率和资源使用问题。在这项工作中，我们首先表明样本复杂性随着系统监督学习任务中的吸收状态的数量而增加，同时对变量尺寸输入更加强大。然后，我们为现有的最先进的MARL算法提出了一种新颖的架构，它使用注意而不是具有吸收状态的完全连接的层。最后，我们展示了这一新颖架构在剧集中创建或销毁的任务中的标准架构显着优于标准架构以及标准的多代理协调任务。

尽管深度强化学习（RL）最近取得了许多成功，但其方法仍然效率低下，这使得在数据方面解决了昂贵的许多问题。我们的目标是通过利用未标记的数据中的丰富监督信号来进行学习状态表示，以解决这一问题。本文介绍了三种不同的表示算法，可以访问传统RL算法使用的数据源的不同子集使用：（i）GRICA受到独立组件分析（ICA）的启发，并训练深层神经网络以输出统计独立的独立特征。输入。 Grica通过最大程度地减少每个功能与其他功能之间的相互信息来做到这一点。此外，格里卡仅需要未分类的环境状态。 （ii）潜在表示预测（LARP）还需要更多的上下文：除了要求状态作为输入外，它还需要先前的状态和连接它们的动作。该方法通过预测当前状态和行动的环境的下一个状态来学习状态表示。预测器与图形搜索算法一起使用。 （iii）重新培训通过训练深层神经网络来学习国家表示，以学习奖励功能的平滑版本。该表示形式用于预处理输入到深度RL，而奖励预测指标用于奖励成型。此方法仅需要环境中的状态奖励对学习表示表示。我们发现，每种方法都有其优势和缺点，并从我们的实验中得出结论，包括无监督的代表性学习在RL解决问题的管道中可以加快学习的速度。

尽管在许多具有挑战性的问题中取得了成功，但增强学习（RL）仍然面临样本效率低下，可以通过将先验知识引入代理人来缓解。但是，在加强学习方面的许多转移技术使教师是专家的局限性假设。在本文中，我们将增强学习中的行动作为推理框架 - 即，在每个状态下的行动分布，类似于教师政策，而不是贝叶斯的先验 - 恢复最先进的策略蒸馏技术。然后，我们提出了一类自适应方法，这些方法可以通过结合奖励成型和辅助正则化损失来鲁sumply动作先验。与先前的工作相反，我们开发了利用次优的动作先验的算法，这些算法可能仍然传授有价值的知识 - 我们称之为软动作先验。拟议的算法通过根据教师在每个州的有用性的估计来调整教师反馈的强度来适应。我们执行表格实验，这表明所提出的方法达到了最先进的性能，在从次优先的先验中学习时超过了它。最后，我们证明了自适应算法在连续动作中的鲁棒性深度RL问题，与现有的策略蒸馏方法相比，自适应算法显着提高了稳定性。

While reinforcement learning (RL) has become a more popular approach for robotics, designing sufficiently informative reward functions for complex tasks has proven to be extremely difficult due their inability to capture human intent and policy exploitation. Preference based RL algorithms seek to overcome these challenges by directly learning reward functions from human feedback. Unfortunately, prior work either requires an unreasonable number of queries implausible for any human to answer or overly restricts the class of reward functions to guarantee the elicitation of the most informative queries, resulting in models that are insufficiently expressive for realistic robotics tasks. Contrary to most works that focus on query selection to \emph{minimize} the amount of data required for learning reward functions, we take an opposite approach: \emph{expanding} the pool of available data by viewing human-in-the-loop RL through the more flexible lens of multi-task learning. Motivated by the success of meta-learning, we pre-train preference models on prior task data and quickly adapt them for new tasks using only a handful of queries. Empirically, we reduce the amount of online feedback needed to train manipulation policies in Meta-World by 20$\times$, and demonstrate the effectiveness of our method on a real Franka Panda Robot. Moreover, this reduction in query-complexity allows us to train robot policies from actual human users. Videos of our results and code can be found at https://sites.google.com/view/few-shot-preference-rl/home.

A long-standing challenge in artificial intelligence is lifelong learning. In lifelong learning, many tasks are presented in sequence and learners must efficiently transfer knowledge between tasks while avoiding catastrophic forgetting over long lifetimes. On these problems, policy reuse and other multi-policy reinforcement learning techniques can learn many tasks. However, they can generate many temporary or permanent policies, resulting in memory issues. Consequently, there is a need for lifetime-scalable methods that continually refine a policy library of a pre-defined size. This paper presents a first approach to lifetime-scalable policy reuse. To pre-select the number of policies, a notion of task capacity, the maximal number of tasks that a policy can accurately solve, is proposed. To evaluate lifetime policy reuse using this method, two state-of-the-art single-actor base-learners are compared: 1) a value-based reinforcement learner, Deep Q-Network (DQN) or Deep Recurrent Q-Network (DRQN); and 2) an actor-critic reinforcement learner, Proximal Policy Optimisation (PPO) with or without Long Short-Term Memory layer. By selecting the number of policies based on task capacity, D(R)QN achieves near-optimal performance with 6 policies in a 27-task MDP domain and 9 policies in an 18-task POMDP domain; with fewer policies, catastrophic forgetting and negative transfer are observed. Due to slow, monotonic improvement, PPO requires fewer policies, 1 policy for the 27-task domain and 4 policies for the 18-task domain, but it learns the tasks with lower accuracy than D(R)QN. These findings validate lifetime-scalable policy reuse and suggest using D(R)QN for larger and PPO for smaller library sizes.

最先进的多机构增强学习（MARL）方法为各种复杂问题提供了有希望的解决方案。然而，这些方法都假定代理执行同步的原始操作执行，因此它们不能真正可扩展到长期胜利的真实世界多代理/机器人任务，这些任务固有地要求代理/机器人以异步的理由，涉及有关高级动作选择的理由。不同的时间。宏观行动分散的部分可观察到的马尔可夫决策过程（MACDEC-POMDP）是在完全合作的多代理任务中不确定的异步决策的一般形式化。在本论文中，我们首先提出了MacDec-Pomdps的一组基于价值的RL方法，其中允许代理在三个范式中使用宏观成果功能执行异步学习和决策：分散学习和控制，集中学习，集中学习和控制，以及分散执行的集中培训（CTDE）。在上述工作的基础上，我们在三个训练范式下制定了一组基于宏观行动的策略梯度算法，在该训练范式下，允许代理以异步方式直接优化其参数化策略。我们在模拟和真实的机器人中评估了我们的方法。经验结果证明了我们在大型多代理问题中的方法的优势，并验证了我们算法在学习具有宏观actions的高质量和异步溶液方面的有效性。