Lifelong learning aims to create AI systems that continuously and incrementally learn during a lifetime, similar to biological learning. Attempts so far have met problems, including catastrophic forgetting, interference among tasks, and the inability to exploit previous knowledge. While considerable research has focused on learning multiple input distributions, typically in classification, lifelong reinforcement learning (LRL) must also deal with variations in the state and transition distributions, and in the reward functions. Modulating masks, recently developed for classification, are particularly suitable to deal with such a large spectrum of task variations. In this paper, we adapted modulating masks to work with deep LRL, specifically PPO and IMPALA agents. The comparison with LRL baselines in both discrete and continuous RL tasks shows competitive performance. We further investigated the use of a linear combination of previously learned masks to exploit previous knowledge when learning new tasks: not only is learning faster, the algorithm solves tasks that we could not otherwise solve from scratch due to extremely sparse rewards. The results suggest that RL with modulating masks is a promising approach to lifelong learning, to the composition of knowledge to learn increasingly complex tasks, and to knowledge reuse for efficient and faster learning.

在各种机器学习问题中，包括转移，多任务，连续和元学习在内，衡量不同任务之间的相似性至关重要。最新的测量任务相似性的方法依赖于体系结构：1）依靠预训练的模型，或2）在任务上进行培训网络，并将正向转移用作任务相似性的代理。在本文中，我们利用了最佳运输理论，并定义了一个新颖的任务嵌入监督分类，该分类是模型的，无训练的，并且能够处理（部分）脱节标签集。简而言之，给定带有地面标签的数据集，我们通过多维缩放和串联数据集样品进行嵌入标签，并具有相应的标签嵌入。然后，我们将两个数据集之间的距离定义为其更新样品之间的2-Wasserstein距离。最后，我们利用2-wasserstein嵌入框架将任务嵌入到矢量空间中，在该空间中，嵌入点之间的欧几里得距离近似于任务之间提出的2-wasserstein距离。我们表明，与最佳传输数据集距离（OTDD）等相关方法相比，所提出的嵌入导致任务的比较显着更快。此外，我们通过各种数值实验证明了我们提出的嵌入的有效性，并显示了我们所提出的距离与任务之间的前进和向后转移之间的统计学意义相关性。

从集合结构的数据学习是一种基本上在机器学习和计算机视觉中的应用程序的重要问题。本文侧重于使用近似最近邻（ANN）解决方案，特别是地区敏感的散列来源的非参数和数据独立于无关的学习。我们考虑从输入集查询设置检索的问题。这样的检索问题需要：1）一种有效的机制来计算集合和2）的距离/异化，以及快速最近邻南搜索的适当数据结构。为此，我们提出切片 - Wasserstein将嵌入作为计算上高效的“Set-2-向量”机制，使下游ANN能够具有理论担保。该组元素被视为来自未知底层分布的样本，并且切片 - Wasserstein距离用于比较集合。我们展示了算法的有效性，表示在各种集合检索数据集上的设定局部敏感散列（Slosh），并将我们提出的嵌入方法与标准集嵌入方法进行比较，包括泛化均值（Gem）嵌入/池，具有额定排序池（FSpool ）和协方差汇总并显示出检索结果的一致性。用于复制我们的结果的代码可在此处提供：\ href {https://github.com/mint-vu/slosh} {https://github.com/mint-vu/slosh}。

元钢筋学习（Meta-RL）算法使得能够快速适应动态环境中的少量样本的任务。通过代理策略网络中的动态表示（通过推理关于任务上下文，模型参数更新或两者）获得的动态表示来实现这样的壮举。然而，由于在策略网络上满足不同的政策，因此获得了超越简单基准问题的快速适应的丰富动态表示是具有挑战性的。本文通过将神经调节引入模块化组件来解决挑战，以增加调节神经元活动的标准策略网络，以便为任务适应提供有效的动态表示。策略网络的建议扩展是在越来越复杂的多个离散和连续控制环境中进行评估。为了证明在Meta-R1中的延伸的一般性和益处，将神经调序的网络应用于两个最先进的META-RL算法（胱瓦和珍珠）。结果表明，与基线相比，通过神经调节增强的Meta-R1产生明显更好的结果和更丰富的动态表示。

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.

Humans have internal models of robots (like their physical capabilities), the world (like what will happen next), and their tasks (like a preferred goal). However, human internal models are not always perfect: for example, it is easy to underestimate a robot's inertia. Nevertheless, these models change and improve over time as humans gather more experience. Interestingly, robot actions influence what this experience is, and therefore influence how people's internal models change. In this work we take a step towards enabling robots to understand the influence they have, leverage it to better assist people, and help human models more quickly align with reality. Our key idea is to model the human's learning as a nonlinear dynamical system which evolves the human's internal model given new observations. We formulate a novel optimization problem to infer the human's learning dynamics from demonstrations that naturally exhibit human learning. We then formalize how robots can influence human learning by embedding the human's learning dynamics model into the robot planning problem. Although our formulations provide concrete problem statements, they are intractable to solve in full generality. We contribute an approximation that sacrifices the complexity of the human internal models we can represent, but enables robots to learn the nonlinear dynamics of these internal models. We evaluate our inference and planning methods in a suite of simulated environments and an in-person user study, where a 7DOF robotic arm teaches participants to be better teleoperators. While influencing human learning remains an open problem, our results demonstrate that this influence is possible and can be helpful in real human-robot interaction.

Explainability is a vibrant research topic in the artificial intelligence community, with growing interest across methods and domains. Much has been written about the topic, yet explainability still lacks shared terminology and a framework capable of providing structural soundness to explanations. In our work, we address these issues by proposing a novel definition of explanation that is a synthesis of what can be found in the literature. We recognize that explanations are not atomic but the product of evidence stemming from the model and its input-output and the human interpretation of this evidence. Furthermore, we fit explanations into the properties of faithfulness (i.e., the explanation being a true description of the model's decision-making) and plausibility (i.e., how much the explanation looks convincing to the user). Using our proposed theoretical framework simplifies how these properties are ope rationalized and provide new insight into common explanation methods that we analyze as case studies.

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.

Graph Neural Networks (GNNs) achieve state-of-the-art performance on graph-structured data across numerous domains. Their underlying ability to represent nodes as summaries of their vicinities has proven effective for homophilous graphs in particular, in which same-type nodes tend to connect. On heterophilous graphs, in which different-type nodes are likely connected, GNNs perform less consistently, as neighborhood information might be less representative or even misleading. On the other hand, GNN performance is not inferior on all heterophilous graphs, and there is a lack of understanding of what other graph properties affect GNN performance. In this work, we highlight the limitations of the widely used homophily ratio and the recent Cross-Class Neighborhood Similarity (CCNS) metric in estimating GNN performance. To overcome these limitations, we introduce 2-hop Neighbor Class Similarity (2NCS), a new quantitative graph structural property that correlates with GNN performance more strongly and consistently than alternative metrics. 2NCS considers two-hop neighborhoods as a theoretically derived consequence of the two-step label propagation process governing GCN's training-inference process. Experiments on one synthetic and eight real-world graph datasets confirm consistent improvements over existing metrics in estimating the accuracy of GCN- and GAT-based architectures on the node classification task.

In recent years, reinforcement learning (RL) has become increasingly successful in its application to science and the process of scientific discovery in general. However, while RL algorithms learn to solve increasingly complex problems, interpreting the solutions they provide becomes ever more challenging. In this work, we gain insights into an RL agent's learned behavior through a post-hoc analysis based on sequence mining and clustering. Specifically, frequent and compact subroutines, used by the agent to solve a given task, are distilled as gadgets and then grouped by various metrics. This process of gadget discovery develops in three stages: First, we use an RL agent to generate data, then, we employ a mining algorithm to extract gadgets and finally, the obtained gadgets are grouped by a density-based clustering algorithm. We demonstrate our method by applying it to two quantum-inspired RL environments. First, we consider simulated quantum optics experiments for the design of high-dimensional multipartite entangled states where the algorithm finds gadgets that correspond to modern interferometer setups. Second, we consider a circuit-based quantum computing environment where the algorithm discovers various gadgets for quantum information processing, such as quantum teleportation. This approach for analyzing the policy of a learned agent is agent and environment agnostic and can yield interesting insights into any agent's policy.