深厚的增强学习（DRL）在各种机器人应用中取得了突破性的成功。自然的结果是采用这种范式来进行关键的任务，其中可以涉及人类安全和昂贵的硬件。在这种情况下，至关重要的是优化基于DRL的代理的性能，同时提供其行为的保证。本文提出了一种新型技术，用于将域专家知识纳入受约束的DRL训练环中。我们的技术利用了基于方案的编程范式，该范式旨在以简单而直观的方式指定此类知识。我们验证了有关流行的机器人地图导航问题，模拟和实际平台的方法。我们的实验表明，使用我们的方法利用专家知识极大地提高了代理的安全性和性能。

这项工作调查了基于课程学习（CL）对代理商的绩效的影响。特别是，我们专注于机器人毛美导航的安全方面，比较标准端到端（E2E）培训策略。为此，我们提出了一种方法，即利用学习（tol）和微调在基于团结的模拟中的微调，以及Robotnik Kairos作为机器人代理。对于公平的比较，我们的评估考虑了对每个学习方法的同等计算需求（即，相同的相互作用和环境的难度数），并确认我们基于CL的方法使用TOL优于E2E方法。特别是，我们提高了培训的政策的平均成功率和安全，导致看不见的测试方案中的碰撞减少了10％。为了进一步确认这些结果，我们采用正式的验证工具来量化加强学习政策的正确行为数量超过所需规范。

我们提出了一种专注于水生导航的安全强化学习的新型基准环境。由于非静止的环境和机器人平台的不确定性，水生导航是一个极具挑战性的任务，因此通过分析训练有素的网络的行为来考虑问题的安全方面至关重要的问题，以避免危险情况（例如，碰撞）。为此，我们考虑基于价值和政策梯度的深度加强学习（DRL），我们提出了一种基于交叉的策略，将基于梯度和梯度的DRL结合以提高样品效率。此外，我们提出了一种基于间隔分析的验证策略，该验证策略检查培训模型在一组所需属性上的行为。我们的结果表明，基于交叉的培训优于先前的DRL方法，而我们的验证允许我们量化违反属性描述的行为的配置数。至关重要，这将作为该应用领域的未来研究的基准。

我们研究了流行的集中训练和分散执行（CTDE）范式中的多机器人发臭导航问题。当每个机器人考虑其路径而不明确地与其他机器人明确分享观察时，这一问题挑战了，可能导致深度加强学习（DRL）中的非静止问题。典型的CTDE算法将联合动作值函数分解为个别函数，以支持合作并实现分散的执行。这种分解涉及限制（例如，单调性），其限制在个体中的新行为的出现，因为从联合动作值开始训练。相比之下，我们为CTDE提出了一种新颖的架构，该架构使用集中式状态值网络来计算联合状态值，该值用于在代理的基于值的更新中注入全局状态信息。因此，考虑到环境的整体状态，每个模型计算其权重的梯度更新。我们的想法遵循Dueling Networks作为联合状态值的单独估计的独立估计，具有提高采样效率的优点，同时提供每个机器人信息，无论全局状态是否为（或不是）有价值的。具有2 4和8个机器人的机器人导航任务的实验，确认了我们对先前CTDE方法的方法的卓越性能（例如，VDN，QMIX）。

在本文中，我们专注于在线学习主动视觉在未知室内环境中的对象的搜索（AVS）的最优策略问题。我们建议POMP++，规划战略，介绍了经典的部分可观察蒙特卡洛规划（POMCP）框架之上的新制剂，允许免费培训，在线政策在未知的环境中学习。我们提出了一个新的信仰振兴战略，允许使用POMCP与动态扩展状态空间来解决在线生成平面地图的。我们评估我们在两个公共标准数据集的方法，AVD由是从真正的3D场景渲染扫描真正的机器人平台和人居ObjectNav收购，用>10％，比国家的the-改善达到最佳的成功率技术方法。

Computational units in artificial neural networks follow a simplified model of biological neurons. In the biological model, the output signal of a neuron runs down the axon, splits following the many branches at its end, and passes identically to all the downward neurons of the network. Each of the downward neurons will use their copy of this signal as one of many inputs dendrites, integrate them all and fire an output, if above some threshold. In the artificial neural network, this translates to the fact that the nonlinear filtering of the signal is performed in the upward neuron, meaning that in practice the same activation is shared between all the downward neurons that use that signal as their input. Dendrites thus play a passive role. We propose a slightly more complex model for the biological neuron, where dendrites play an active role: the activation in the output of the upward neuron becomes optional, and instead the signals going through each dendrite undergo independent nonlinear filterings, before the linear combination. We implement this new model into a ReLU computational unit and discuss its biological plausibility. We compare this new computational unit with the standard one and describe it from a geometrical point of view. We provide a Keras implementation of this unit into fully connected and convolutional layers and estimate their FLOPs and weights change. We then use these layers in ResNet architectures on CIFAR-10, CIFAR-100, Imagenette, and Imagewoof, obtaining performance improvements over standard ResNets up to 1.73%. Finally, we prove a universal representation theorem for continuous functions on compact sets and show that this new unit has more representational power than its standard counterpart.

Fruit is a key crop in worldwide agriculture feeding millions of people. The standard supply chain of fruit products involves quality checks to guarantee freshness, taste, and, most of all, safety. An important factor that determines fruit quality is its stage of ripening. This is usually manually classified by experts in the field, which makes it a labor-intensive and error-prone process. Thus, there is an arising need for automation in the process of fruit ripeness classification. Many automatic methods have been proposed that employ a variety of feature descriptors for the food item to be graded. Machine learning and deep learning techniques dominate the top-performing methods. Furthermore, deep learning can operate on raw data and thus relieve the users from having to compute complex engineered features, which are often crop-specific. In this survey, we review the latest methods proposed in the literature to automatize fruit ripeness classification, highlighting the most common feature descriptors they operate on.

Artificial neural networks can learn complex, salient data features to achieve a given task. On the opposite end of the spectrum, mathematically grounded methods such as topological data analysis allow users to design analysis pipelines fully aware of data constraints and symmetries. We introduce a class of persistence-based neural network layers. Persistence-based layers allow the users to easily inject knowledge about symmetries (equivariance) respected by the data, are equipped with learnable weights, and can be composed with state-of-the-art neural architectures.

In this work we introduce reinforcement learning techniques for solving lexicographic multi-objective problems. These are problems that involve multiple reward signals, and where the goal is to learn a policy that maximises the first reward signal, and subject to this constraint also maximises the second reward signal, and so on. We present a family of both action-value and policy gradient algorithms that can be used to solve such problems, and prove that they converge to policies that are lexicographically optimal. We evaluate the scalability and performance of these algorithms empirically, demonstrating their practical applicability. As a more specific application, we show how our algorithms can be used to impose safety constraints on the behaviour of an agent, and compare their performance in this context with that of other constrained reinforcement learning algorithms.

In contextual linear bandits, the reward function is assumed to be a linear combination of an unknown reward vector and a given embedding of context-arm pairs. In practice, the embedding is often learned at the same time as the reward vector, thus leading to an online representation learning problem. Existing approaches to representation learning in contextual bandits are either very generic (e.g., model-selection techniques or algorithms for learning with arbitrary function classes) or specialized to particular structures (e.g., nested features or representations with certain spectral properties). As a result, the understanding of the cost of representation learning in contextual linear bandit is still limited. In this paper, we take a systematic approach to the problem and provide a comprehensive study through an instance-dependent perspective. We show that representation learning is fundamentally more complex than linear bandits (i.e., learning with a given representation). In particular, learning with a given set of representations is never simpler than learning with the worst realizable representation in the set, while we show cases where it can be arbitrarily harder. We complement this result with an extensive discussion of how it relates to existing literature and we illustrate positive instances where representation learning is as complex as learning with a fixed representation and where sub-logarithmic regret is achievable.