建立可以探索开放式环境的自主机器，发现可能的互动，自主构建技能的曲目是人工智能的一般目标。发展方法争辩说，这只能通过可以生成，选择和学习解决自己问题的自主和本质上动机的学习代理人来实现。近年来，我们已经看到了发育方法的融合，特别是发展机器人，具有深度加强学习（RL）方法，形成了发展机器学习的新领域。在这个新域中，我们在这里审查了一组方法，其中深入RL算法训练，以解决自主获取的开放式曲目的发展机器人问题。本质上动机的目标条件RL算法训练代理商学习代表，产生和追求自己的目标。自我生成目标需要学习紧凑的目标编码以及它们的相关目标 - 成就函数，这导致与传统的RL算法相比，这导致了新的挑战，该算法设计用于使用外部奖励信号解决预定义的目标集。本文提出了在深度RL和发育方法的交叉口中进行了这些方法的类型，调查了最近的方法并讨论了未来的途径。

增强学习（RL）研究领域非常活跃，并具有重要的新贡献；特别是考虑到深RL（DRL）的新兴领域。但是，仍然需要解决许多科学和技术挑战，其中我们可以提及抽象行动的能力或在稀疏回报环境中探索环境的难以通过内在动机（IM）来解决的。我们建议通过基于信息理论的新分类法调查这些研究工作：我们在计算上重新审视了惊喜，新颖性和技能学习的概念。这使我们能够确定方法的优势和缺点，并展示当前的研究前景。我们的分析表明，新颖性和惊喜可以帮助建立可转移技能的层次结构，从而进一步抽象环境并使勘探过程更加健壮。

与一组复杂的RL问题有关的目标条件加固学习（GCRL）训练代理在特定情况下实现不同的目标。与仅根据州或观察结果了解政策的标准RL解决方案相比，GCRL还要求代理商根据不同的目标做出决策。在这项调查中，我们对GCRL的挑战和算法进行了全面的概述。首先，我们回答该领域研究的基本问题。然后，我们解释了如何代表目标并介绍如何从不同角度设计现有解决方案。最后，我们得出结论，并讨论最近研究重点的潜在未来前景。

The past few years have seen rapid progress in combining reinforcement learning (RL) with deep learning. Various breakthroughs ranging from games to robotics have spurred the interest in designing sophisticated RL algorithms and systems. However, the prevailing workflow in RL is to learn tabula rasa, which may incur computational inefficiency. This precludes continuous deployment of RL algorithms and potentially excludes researchers without large-scale computing resources. In many other areas of machine learning, the pretraining paradigm has shown to be effective in acquiring transferable knowledge, which can be utilized for a variety of downstream tasks. Recently, we saw a surge of interest in Pretraining for Deep RL with promising results. However, much of the research has been based on different experimental settings. Due to the nature of RL, pretraining in this field is faced with unique challenges and hence requires new design principles. In this survey, we seek to systematically review existing works in pretraining for deep reinforcement learning, provide a taxonomy of these methods, discuss each sub-field, and bring attention to open problems and future directions.

深度强化学习（DRL）和深度多机构的强化学习（MARL）在包括游戏AI，自动驾驶汽车，机器人技术等各种领域取得了巨大的成功。但是，众所周知，DRL和Deep MARL代理的样本效率低下，即使对于相对简单的问题设置，通常也需要数百万个相互作用，从而阻止了在实地场景中的广泛应用和部署。背后的一个瓶颈挑战是众所周知的探索问题，即如何有效地探索环境和收集信息丰富的经验，从而使政策学习受益于最佳研究。在稀疏的奖励，吵闹的干扰，长距离和非平稳的共同学习者的复杂环境中，这个问题变得更加具有挑战性。在本文中，我们对单格和多代理RL的现有勘探方法进行了全面的调查。我们通过确定有效探索的几个关键挑战开始调查。除了上述两个主要分支外，我们还包括其他具有不同思想和技术的著名探索方法。除了算法分析外，我们还对一组常用基准的DRL进行了全面和统一的经验比较。根据我们的算法和实证研究，我们终于总结了DRL和Deep Marl中探索的公开问题，并指出了一些未来的方向。

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.

虽然深增强学习已成为连续决策问题的有希望的机器学习方法，但对于自动驾驶或医疗应用等高利害域来说仍然不够成熟。在这种情况下，学习的政策需要例如可解释，因此可以在任何部署之前检查它（例如，出于安全性和验证原因）。本调查概述了各种方法，以实现加固学习（RL）的更高可解释性。为此，我们将解释性（作为模型的财产区分开来和解释性（作为HOC操作后的讲话，通过代理的干预），并在RL的背景下讨论它们，并强调前概念。特别是，我们认为可译文的RL可能会拥抱不同的刻面：可解释的投入，可解释（转型/奖励）模型和可解释的决策。根据该计划，我们总结和分析了与可解释的RL相关的最近工作，重点是过去10年来发表的论文。我们还简要讨论了一些相关的研究领域并指向一些潜在的有前途的研究方向。

深入学习的强化学习（RL）的结合导致了一系列令人印象深刻的壮举，许多相信（深）RL提供了一般能力的代理。然而，RL代理商的成功往往对培训过程中的设计选择非常敏感，这可能需要繁琐和易于易于的手动调整。这使得利用RL对新问题充满挑战，同时也限制了其全部潜力。在许多其他机器学习领域，AutomL已经示出了可以自动化这样的设计选择，并且在应用于RL时也会产生有希望的初始结果。然而，自动化强化学习（AutorL）不仅涉及Automl的标准应用，而且还包括RL独特的额外挑战，其自然地产生了不同的方法。因此，Autorl已成为RL中的一个重要研究领域，提供来自RNA设计的各种应用中的承诺，以便玩游戏等游戏。鉴于RL中考虑的方法和环境的多样性，在不同的子领域进行了大部分研究，从Meta学习到进化。在这项调查中，我们寻求统一自动的领域，我们提供常见的分类法，详细讨论每个区域并对研究人员来说是一个兴趣的开放问题。

深度加强学习概括（RL）的研究旨在产生RL算法，其政策概括为在部署时间进行新的未经调整情况，避免对其培训环境的过度接受。如果我们要在现实世界的情景中部署强化学习算法，那么解决这一点至关重要，那么环境将多样化，动态和不可预测。该调查是这个新生领域的概述。我们为讨论不同的概括问题提供统一的形式主义和术语，在以前的作品上建立不同的概括问题。我们继续对现有的基准进行分类，以及用于解决泛化问题的当前方法。最后，我们提供了对现场当前状态的关键讨论，包括未来工作的建议。在其他结论之外，我们认为，采取纯粹的程序内容生成方法，基准设计不利于泛化的进展，我们建议快速在线适应和将RL特定问题解决作为未来泛化方法的一些领域，我们推荐在UniTexplorated问题设置中构建基准测试，例如离线RL泛化和奖励函数变化。

Designing agents, capable of learning autonomously a wide range of skills is critical in order to increase the scope of reinforcement learning. It will both increase the diversity of learned skills and reduce the burden of manually designing reward functions for each skill. Self-supervised agents, setting their own goals, and trying to maximize the diversity of those goals have shown great promise towards this end. However, a currently known limitation of agents trying to maximize the diversity of sampled goals is that they tend to get attracted to noise or more generally to parts of the environments that cannot be controlled (distractors). When agents have access to predefined goal features or expert knowledge, absolute Learning Progress (ALP) provides a way to distinguish between regions that can be controlled and those that cannot. However, those methods often fall short when the agents are only provided with raw sensory inputs such as images. In this work we extend those concepts to unsupervised image-based goal exploration. We propose a framework that allows agents to autonomously identify and ignore noisy distracting regions while searching for novelty in the learnable regions to both improve overall performance and avoid catastrophic forgetting. Our framework can be combined with any state-of-the-art novelty seeking goal exploration approaches. We construct a rich 3D image based environment with distractors. Experiments on this environment show that agents using our framework successfully identify interesting regions of the environment, resulting in drastically improved performances. The source code is available at https://sites.google.com/view/grimgep.

代理商学习广泛适用和通用策略具有重要意义，可以实现包括图像和文本描述在内的各种目标。考虑到这类感知的目标，深度加强学习研究的前沿是学习一个没有手工制作奖励的目标条件政策。要了解这种政策，最近的作品通常会像奖励到明确的嵌入空间中的给定目标的非参数距离。从不同的观点来看，我们提出了一种新的无监督学习方法，名为目标条件政策，具有内在动机（GPIM），共同学习抽象级别政策和目标条件的政策。摘要级别策略在潜在变量上被调节，以优化鉴别器，并发现进一步的不同状态，进一步呈现为目标条件策略的感知特定目标。学习鉴别者作为目标条件策略的内在奖励功能，以模仿抽象级别政策引起的轨迹。各种机器人任务的实验证明了我们所提出的GPIM方法的有效性和效率，其基本上优于现有技术。

Imitation learning techniques aim to mimic human behavior in a given task. An agent (a learning machine) is trained to perform a task from demonstrations by learning a mapping between observations and actions. The idea of teaching by imitation has been around for many years, however, the field is gaining attention recently due to advances in computing and sensing as well as rising demand for intelligent applications. The paradigm of learning by imitation is gaining popularity because it facilitates teaching complex tasks with minimal expert knowledge of the tasks. Generic imitation learning methods could potentially reduce the problem of teaching a task to that of providing demonstrations; without the need for explicit programming or designing reward functions specific to the task. Modern sensors are able to collect and transmit high volumes of data rapidly, and processors with high computational power allow fast processing that maps the sensory data to actions in a timely manner. This opens the door for many potential AI applications that require real-time perception and reaction such as humanoid robots, self-driving vehicles, human computer interaction and computer games to name a few. However, specialized algorithms are needed to effectively and robustly learn models as learning by imitation poses its own set of challenges. In this paper, we survey imitation learning methods and present design options in different steps of the learning process. We introduce a background and motivation for the field as well as highlight challenges specific to the imitation problem. Methods for designing and evaluating imitation learning tasks are categorized and reviewed. Special attention is given to learning methods in robotics and games as these domains are the most popular in the literature and provide a wide array of problems and methodologies. We extensively discuss combining imitation learning approaches using different sources and methods, as well as incorporating other motion learning methods to enhance imitation. We also discuss the potential impact on industry, present major applications and highlight current and future research directions.

在流行媒体中，人造代理商的意识出现与同时实现人类或超人水平智力的那些相同的代理之间通常存在联系。在这项工作中，我们探讨了意识和智力之间这种看似直观的联系的有效性和潜在应用。我们通过研究与三种当代意识功能理论相关的认知能力：全球工作空间理论（GWT），信息生成理论（IGT）和注意力模式理论（AST）。我们发现，这三种理论都将有意识的功能专门与人类领域将军智力的某些方面联系起来。有了这个见解，我们转向人工智能领域（AI），发现尽管远未证明一般智能，但许多最先进的深度学习方法已经开始纳入三个功能的关键方面理论。确定了这一趋势后，我们以人类心理时间旅行的激励例子来提出方式，其中三种理论中每种理论的见解都可以合并为一个单一的统一和可实施的模型。鉴于三种功能理论中的每一种都可以通过认知能力来实现这一可能，因此，具有精神时间旅行的人造代理不仅具有比当前方法更大的一般智力，而且还与我们当前对意识功能作用的理解更加一致在人类中，这使其成为AI研究的有希望的近期目标。

Learning goal-directed behavior in environments with sparse feedback is a major challenge for reinforcement learning algorithms. The primary difficulty arises due to insufficient exploration, resulting in an agent being unable to learn robust value functions. Intrinsically motivated agents can explore new behavior for its own sake rather than to directly solve problems. Such intrinsic behaviors could eventually help the agent solve tasks posed by the environment. We present hierarchical-DQN (h-DQN), a framework to integrate hierarchical value functions, operating at different temporal scales, with intrinsically motivated deep reinforcement learning. A top-level value function learns a policy over intrinsic goals, and a lower-level function learns a policy over atomic actions to satisfy the given goals. h-DQN allows for flexible goal specifications, such as functions over entities and relations. This provides an efficient space for exploration in complicated environments. We demonstrate the strength of our approach on two problems with very sparse, delayed feedback: (1) a complex discrete stochastic decision process, and (2) the classic ATARI game 'Montezuma's Revenge'.

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.

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.

Recent progress in artificial intelligence (AI) has renewed interest in building systems that learn and think like people. Many advances have come from using deep neural networks trained end-to-end in tasks such as object recognition, video games, and board games, achieving performance that equals or even beats humans in some respects. Despite their biological inspiration and performance achievements, these systems differ from human intelligence in crucial ways. We review progress in cognitive science suggesting that truly human-like learning and thinking machines will have to reach beyond current engineering trends in both what they learn, and how they learn it. Specifically, we argue that these machines should (a) build causal models of the world that support explanation and understanding, rather than merely solving pattern recognition problems; (b) ground learning in intuitive theories of physics and psychology, to support and enrich the knowledge that is learned; and (c) harness compositionality and learning-to-learn to rapidly acquire and generalize knowledge to new tasks and situations. We suggest concrete challenges and promising routes towards these goals that can combine the strengths of recent neural network advances with more structured cognitive models.

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.

值得信赖的强化学习算法应有能力解决挑战性的现实问题，包括{Robustly}处理不确定性，满足{安全}的限制以避免灾难性的失败，以及在部署过程中{prencepentiming}以避免灾难性的失败}。这项研究旨在概述这些可信赖的强化学习的主要观点，即考虑其在鲁棒性，安全性和概括性上的内在脆弱性。特别是，我们给出严格的表述，对相应的方法进行分类，并讨论每个观点的基准。此外，我们提供了一个前景部分，以刺激有希望的未来方向，并简要讨论考虑人类反馈的外部漏洞。我们希望这项调查可以在统一的框架中将单独的研究汇合在一起，并促进强化学习的可信度。

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.