深度强化学习（RL）涉及使用深神经网络（DNN）来做出顺序决策，以最大程度地提高奖励。对于许多任务，由深度RL政策产生的一系列动作顺序对于人类来说可能是漫长而难以理解的。人类解释的一个关键组成部分是选择性，仅叙述关键决定和原因。使深层RL代理具有这种能力，将使他们的产生政策从人的角度更容易理解，并产生一套简洁的指示，以帮助学习未来的代理商。为此，我们使用具有情节内存系统的深度RL代理来识别和叙述策略执行期间的关键决策。我们表明，这些决策形成了一个简短的可读解释，也可以用来以算法独立的方式加快对天真的深度RL代理的学习。

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.

Non-parametric episodic memory can be used to quickly latch onto high-reward experience in reinforcement learning tasks. In contrast to parametric deep reinforcement learning approaches, these methods only need to discover the solution once, and may then repeatedly solve the task. However, episodic control solutions are stored in discrete tables, and this approach has so far only been applied to discrete action space problems. Therefore, this paper introduces Continuous Episodic Control (CEC), a novel non-parametric episodic memory algorithm for sequential decision making in problems with a continuous action space. Results on several sparse-reward continuous control environments show that our proposed method learns faster than state-of-the-art model-free RL and memory-augmented RL algorithms, while maintaining good long-run performance as well. In short, CEC can be a fast approach for learning in continuous control tasks, and a useful addition to parametric RL methods in a hybrid approach as well.

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.

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。

人类环境通常由明确和复杂的规则集调节。将强化学习（RL）代理集成到这样的环境中，激励在规则密集和异常的环境中表现良好的学习机制的发展，例如在受监管道路上自动驾驶。在本文中，我们提出了一种通过将体验缓冲区分区的经验组织经验，以根据每次解释标记的群集。我们呈现与模块化规则集和9个学习任务兼容的离散和连续导航环境。对于具有可解释的规则集的环境，我们将基于规则的解释转换为基于案例的解释，通过将状态转换分配到标有解释标记的群集。这使我们可以以课程和任务为导向的方式进行样本，专注于事件的稀有性，重要性和含义。我们标记这个概念解释 - 意识（XA）。我们使用内部和群集内部优先级执行XA体验重放（XAER），并引入DQN，TD3和SAC的XA兼容版本。与传统优先考虑体验重放基线相比，性能与这些算法的XA版本始终如一，表明可以使用解释工程代替具有可解释功能的环境的奖励工程。

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.

我们考虑单个强化学习与基于事件驱动的代理商金融市场模型相互作用时学习最佳执行代理的学习动力。交易在事件时间内通过匹配引擎进行异步进行。最佳执行代理在不同级别的初始订单尺寸和不同尺寸的状态空间上进行考虑。使用校准方法考虑了对基于代理的模型和市场的影响，该方法探讨了经验性风格化事实和价格影响曲线的变化。收敛，音量轨迹和动作痕迹图用于可视化学习动力学。这表明了最佳执行代理如何在模拟的反应性市场框架内学习最佳交易决策，以及如何通过引入战略订单分类来改变模拟市场的反反应。

由于它们所需的大量集中，最深度增强学习算法的状态是对渐近性能的大量集中的效率低。由哺乳动物海马的启发的episodic加强学习（ERL）算法通常使用扩展的内存系统从过去的事件开始学习，以克服这个样本效率问题。然而，这种内存增强通常用作仅仅是缓冲区，从中绘制了孤立的过去经验，以便以离线方式学习（例如，重播）。这里，我们证明包括从集扩展抽样顺序导出的所获取的内存内容中的偏差来提高弹性控制算法的样本和存储器效率。我们在觅食任务中测试了我们的顺序焦点控制（SEC）模型，以显示存储和使用集成剧集作为事件序列导致更快的学习，与较少的内存要求相反，与隔离的缓冲区相比只有事件。我们还研究了内存约束的影响，忘记了SEC算法的顺序和非顺序版本。此外，我们讨论了类似海马的快速记忆系统如何在哺乳动物大脑中引导慢速皮质和皮质学习习惯的习惯。

In this paper, we build on advances introduced by the Deep Q-Networks (DQN) approach to extend the multi-objective tabular Reinforcement Learning (RL) algorithm W-learning to large state spaces. W-learning algorithm can naturally solve the competition between multiple single policies in multi-objective environments. However, the tabular version does not scale well to environments with large state spaces. To address this issue, we replace underlying Q-tables with DQN, and propose an addition of W-Networks, as a replacement for tabular weights (W) representations. We evaluate the resulting Deep W-Networks (DWN) approach in two widely-accepted multi-objective RL benchmarks: deep sea treasure and multi-objective mountain car. We show that DWN solves the competition between multiple policies while outperforming the baseline in the form of a DQN solution. Additionally, we demonstrate that the proposed algorithm can find the Pareto front in both tested environments.

Go-Explore achieved breakthrough performance on challenging reinforcement learning (RL) tasks with sparse rewards. The key insight of Go-Explore was that successful exploration requires an agent to first return to an interesting state ('Go'), and only then explore into unknown terrain ('Explore'). We refer to such exploration after a goal is reached as 'post-exploration'. In this paper, we present a clear ablation study of post-exploration in a general intrinsically motivated goal exploration process (IMGEP) framework, that the Go-Explore paper did not show. We study the isolated potential of post-exploration, by turning it on and off within the same algorithm under both tabular and deep RL settings on both discrete navigation and continuous control tasks. Experiments on a range of MiniGrid and Mujoco environments show that post-exploration indeed helps IMGEP agents reach more diverse states and boosts their performance. In short, our work suggests that RL researchers should consider to use post-exploration in IMGEP when possible since it is effective, method-agnostic and easy to implement.

动物和人工代理商都受益于支持跨任务的快速学习的国家表示，使他们能够有效地遍历其环境以获得奖励状态。在固定政策下衡量预期累积，贴现国家占用的后续代表（SR），可以在否则的马尔可维亚环境中有效地转移到不同的奖励结构，并假设生物行为和神经活动的基础方面。然而，在现实世界中，奖励可能会移动或仅用于消费一次，可能只是将位置或者代理可以简单地旨在尽可能快地到达目标状态，而不会产生人工强加的任务视野的约束。在这种情况下，最具行为相关的代表将携带有关代理人可能首先达到兴趣国的信息的信息，而不是在可能的无限时间跨度访问它们的频率。为了反映此类需求，我们介绍了第一次占用代表（FR），该代表（FR），该代表（FR）衡量预期的时间折扣首次访问状态。我们证明FR有助于探索，选择有效的路径到所需状态，允许代理在某些条件下规划由一系列子板定义的可透明的最佳轨迹，并引起避免威胁刺激的动物类似的行为。

在这项工作中，我们提出了一种初步调查一种名为DYNA-T的新算法。在钢筋学习（RL）中，规划代理有自己的环境表示作为模型。要发现与环境互动的最佳政策，代理商会收集试验和错误时尚的经验。经验可用于学习更好的模型或直接改进价值函数和政策。通常是分离的，Dyna-Q是一种混合方法，在每次迭代，利用真实体验更新模型以及值函数，同时使用模拟数据从其模型中的应用程序进行行动。然而，规划过程是计算昂贵的并且强烈取决于国家行动空间的维度。我们建议在模拟体验上构建一个上置信树（UCT），并在在线学习过程中搜索要选择的最佳动作。我们证明了我们提出的方法对来自Open AI的三个测试平台环境的一系列初步测试的有效性。与Dyna-Q相比，Dyna-T通过选择更强大的动作选择策略来优于随机环境中的最先进的RL代理。

分布式多智能经纪增强学习（Marl）算法最近引起了兴趣激增，主要是由于深神经网络（DNN）的最新进步。由于利用固定奖励模型来学习基础值函数，传统的基于模型（MB）或无模型（MF）RL算法不可直接适用于MARL问题。虽然涉及单一代理时，基于DNN的解决方案完全良好地表现出，但是这种方法无法完全推广到MARL问题的复杂性。换句话说，尽管最近的基于DNN的DNN用于多种子体环境的方法取得了卓越的性能，但它们仍然容易出现过度，对参数选择的高敏感性，以及样本低效率。本文提出了多代理自适应Kalman时间差（MAK-TD）框架及其继任者表示的基于代表的变体，称为MAK-SR。直观地说，主要目标是利用卡尔曼滤波（KF）的独特特征，如不确定性建模和在线二阶学习。提议的MAK-TD / SR框架考虑了与高维多算法环境相关联的动作空间的连续性，并利用卡尔曼时间差（KTD）来解决参数不确定性。通过利用KTD框架，SR学习过程被建模到过滤问题，其中径向基函数（RBF）估计器用于将连续空间编码为特征向量。另一方面，对于学习本地化奖励功能，我们求助于多种模型自适应估计（MMAE），处理缺乏关于观察噪声协方差和观察映射功能的先前知识。拟议的MAK-TD / SR框架通过多个实验进行评估，该实验通过Openai Gym Marl基准实施。

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.

强化学习（RL）为解决各种复杂的决策任务提供了新的机会。但是，现代的RL算法，例如，深Q学习是基于深层神经网络，在Edge设备上运行时的计算成本很高。在本文中，我们提出了QHD，一种高度增强的学习，它模仿了大脑特性，以实现健壮和实时学习。 QHD依靠轻巧的大脑启发模型来学习未知环境中的最佳政策。我们首先建立一个新颖的数学基础和编码模块，该模块将状态行动空间映射到高维空间中。因此，我们开发了一个高维回归模型，以近似Q值函数。 QHD驱动的代理通过比较每个可能动作的Q值来做出决定。我们评估了不同的RL培训批量和本地记忆能力对QHD学习质量的影响。我们的QHD也能够以微小的本地记忆能力在线学习，这与培训批量大小一样小。 QHD通过进一步降低记忆容量和批处理大小来提供实时学习。这使得QHD适用于在边缘环境中高效的增强学习，这对于支持在线和实时学习至关重要。我们的解决方案还支持少量的重播批量大小，与DQN相比，该批量的速度为12.3倍，同时确保质量损失最小。我们的评估显示了实时学习的QHD能力，比最先进的Deep RL算法提供了34.6倍的速度和更高的学习质量。

本文介绍了用于交易单一资产的双重Q网络算法，即E-MINI S＆P 500连续期货合约。我们使用经过验证的设置作为我们环境的基础，并具有多个扩展。我们的贸易代理商的功能不断扩展，包括其他资产，例如商品，从而产生了四种型号。我们还应对环境条件，包括成本和危机。我们的贸易代理商首先接受了特定时间段的培训，并根据新数据进行了测试，并将其与长期策略（市场）进行了比较。我们分析了各种模型与样本中/样本外性能之间有关环境的差异。实验结果表明，贸易代理人遵循适当的行为。它可以将其政策调整为不同的情况，例如在存在交易成本时更广泛地使用中性位置。此外，净资产价值超过了基准的净值，代理商在测试集中的市场优于市场。我们使用DDQN算法对代理商在金融领域中的行为提供初步见解。这项研究的结果可用于进一步发展。

Reinforcement learning is a machine learning approach based on behavioral psychology. It is focused on learning agents that can acquire knowledge and learn to carry out new tasks by interacting with the environment. However, a problem occurs when reinforcement learning is used in critical contexts where the users of the system need to have more information and reliability for the actions executed by an agent. In this regard, explainable reinforcement learning seeks to provide to an agent in training with methods in order to explain its behavior in such a way that users with no experience in machine learning could understand the agent's behavior. One of these is the memory-based explainable reinforcement learning method that is used to compute probabilities of success for each state-action pair using an episodic memory. In this work, we propose to make use of the memory-based explainable reinforcement learning method in a hierarchical environment composed of sub-tasks that need to be first addressed to solve a more complex task. The end goal is to verify if it is possible to provide to the agent the ability to explain its actions in the global task as well as in the sub-tasks. The results obtained showed that it is possible to use the memory-based method in hierarchical environments with high-level tasks and compute the probabilities of success to be used as a basis for explaining the agent's behavior.

钢筋学习的长期目标是建立智能代理，表现出快速学习，灵活地转移适于人类和动物的技能。本文调查了两个框架来解决这些目标的框架：情节控制和继承功能。epiSodic控制是一种认知的灵感方法，依赖于情节内存，是代理经历的基于实例的内存模型。同时，继承者功能和广义政策改进（SF＆GPI）是一个元和传输学习框架，允许学习可以有效地重复使用不同奖励功能的稍后任务的任务的策略。单独地，这两种技术表明令人印象深刻的结果，从而大大提高了样本效率和优雅的重复使用了先前学习的政策。因此，我们概述了两种方法中的两种方法的组合，并经验证明其益处。

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.