在本文中，我们介绍了Siammask，这是一个实时使用相同简单方法实时执行视觉对象跟踪和视频对象分割的框架。我们通过通过二进制细分任务来增强其损失，从而改善了流行的全面暹罗方法的离线培训程序。离线训练完成后，SiamMask只需要一个单个边界框来初始化，并且可以同时在高框架速率下进行视觉对象跟踪和分割。此外，我们表明可以通过简单地以级联的方式重新使用多任务模型来扩展框架以处理多个对象跟踪和细分。实验结果表明，我们的方法具有较高的处理效率，每秒约55帧。它可以在视觉对象跟踪基准测试中产生实时最新结果，同时以高速进行视频对象分割基准测试以高速显示竞争性能。

跟踪视频感兴趣的对象是计算机视觉中最受欢迎和最广泛应用的问题之一。然而，随着年的几年，寒武纪的用例和基准已经将问题分散在多种不同的实验设置中。因此，文献也已经分散，现在社区提出的新方法通常是专门用于仅适合一个特定的设置。要了解在多大程度上，这项专业化是必要的，在这项工作中，我们展示了UnitRack，一个解决方案来解决同一框架内的五个不同任务。 Unitrack由单一和任务不可知的外观模型组成，可以以监督或自我监督的方式学习，以及解决个人任务的多个`“头”，并且不需要培训。我们展示了在该框架内可以解决的大多数跟踪任务，并且可以成功地成功地使用相同的外观模型来获得对针对考虑大多数任务的专业方法具有竞争力的结果。该框架还允许我们分析具有最新自我监督方法获得的外观模型，从而扩展了他们的评估并与更大种类的重要问题进行比较。

epiSodic学习是对几枪学习感兴趣的研究人员和从业者的流行练习。它包括在一系列学习问题（或剧集）中组织培训，每个人分为小型训练和验证子集，以模仿评估期间遇到的情况。但这总是必要吗？在本文中，我们调查了在集发作的级别使用非参数方法，例如最近邻居等方法的焦点学习的有用性。对于这些方法，我们不仅展示了广州学习的限制是如何不必要的，而是他们实际上导致利用培训批次的数据低效方式。我们通过匹配和原型网络进行广泛的消融实验，其中两个最流行的方法在集中的级别使用非参数方法。他们的“非焦化”对应物具有很大的更简单，具有较少的近似参数，并在多个镜头分类数据集中提高它们的性能。

In this paper we illustrate how to perform both visual object tracking and semi-supervised video object segmentation, in real-time, with a single simple approach. Our method, dubbed SiamMask, improves the offline training procedure of popular fully-convolutional Siamese approaches for object tracking by augmenting their loss with a binary segmentation task. Once trained, SiamMask solely relies on a single bounding box initialisation and operates online, producing class-agnostic object segmentation masks and rotated bounding boxes at 55 frames per second. Despite its simplicity, versatility and fast speed, our strategy allows us to establish a new state of the art among real-time trackers on VOT-2018, while at the same time demonstrating competitive performance and the best speed for the semisupervised video object segmentation task on DAVIS-2016 and DAVIS-2017. The project website is http://www. robots.ox.ac.uk/ ˜qwang/SiamMask.

传统上通过在线学习物体的外观模型来解决任意对象跟踪问题，作为视频本身的唯一培训数据。尽管这些方法的成功，但他们的在线方法本身限制了他们可以学习的模型的丰富性。最近，已经进行了几次尝试利用深度卷积网络的表现力。然而，当预先知道对象轨道时，有必要在线执行随机梯度下降以调整网络的权重，严重影响系统的速度。本文在ILSVRC15数据集上装备了一种基本的跟踪算法，该历程在ILSVRC15数据集上训练了训练的端到端，用于视频中的对象检测。我们的跟踪器以超出实时的帧速率运行，尽管其极端简单，但在多个基准中实现了最先进的性能。

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.

Neuromorphic systems require user-friendly software to support the design and optimization of experiments. In this work, we address this need by presenting our development of a machine learning-based modeling framework for the BrainScaleS-2 neuromorphic system. This work represents an improvement over previous efforts, which either focused on the matrix-multiplication mode of BrainScaleS-2 or lacked full automation. Our framework, called hxtorch.snn, enables the hardware-in-the-loop training of spiking neural networks within PyTorch, including support for auto differentiation in a fully-automated hardware experiment workflow. In addition, hxtorch.snn facilitates seamless transitions between emulating on hardware and simulating in software. We demonstrate the capabilities of hxtorch.snn on a classification task using the Yin-Yang dataset employing a gradient-based approach with surrogate gradients and densely sampled membrane observations from the BrainScaleS-2 hardware system.

Generalisation to unseen contexts remains a challenge for embodied navigation agents. In the context of semantic audio-visual navigation (SAVi) tasks, the notion of generalisation should include both generalising to unseen indoor visual scenes as well as generalising to unheard sounding objects. However, previous SAVi task definitions do not include evaluation conditions on truly novel sounding objects, resorting instead to evaluating agents on unheard sound clips of known objects; meanwhile, previous SAVi methods do not include explicit mechanisms for incorporating domain knowledge about object and region semantics. These weaknesses limit the development and assessment of models' abilities to generalise their learned experience. In this work, we introduce the use of knowledge-driven scene priors in the semantic audio-visual embodied navigation task: we combine semantic information from our novel knowledge graph that encodes object-region relations, spatial knowledge from dual Graph Encoder Networks, and background knowledge from a series of pre-training tasks -- all within a reinforcement learning framework for audio-visual navigation. We also define a new audio-visual navigation sub-task, where agents are evaluated on novel sounding objects, as opposed to unheard clips of known objects. We show improvements over strong baselines in generalisation to unseen regions and novel sounding objects, within the Habitat-Matterport3D simulation environment, under the SoundSpaces task.

Multi-document summarization (MDS) has traditionally been studied assuming a set of ground-truth topic-related input documents is provided. In practice, the input document set is unlikely to be available a priori and would need to be retrieved based on an information need, a setting we call open-domain MDS. We experiment with current state-of-the-art retrieval and summarization models on several popular MDS datasets extended to the open-domain setting. We find that existing summarizers suffer large reductions in performance when applied as-is to this more realistic task, though training summarizers with retrieved inputs can reduce their sensitivity retrieval errors. To further probe these findings, we conduct perturbation experiments on summarizer inputs to study the impact of different types of document retrieval errors. Based on our results, we provide practical guidelines to help facilitate a shift to open-domain MDS. We release our code and experimental results alongside all data or model artifacts created during our investigation.

We consider the problem of two active particles in 2D complex flows with the multi-objective goals of minimizing both the dispersion rate and the energy consumption of the pair. We approach the problem by means of Multi Objective Reinforcement Learning (MORL), combining scalarization techniques together with a Q-learning algorithm, for Lagrangian drifters that have variable swimming velocity. We show that MORL is able to find a set of trade-off solutions forming an optimal Pareto frontier. As a benchmark, we show that a set of heuristic strategies are dominated by the MORL solutions. We consider the situation in which the agents cannot update their control variables continuously, but only after a discrete (decision) time, $\tau$. We show that there is a range of decision times, in between the Lyapunov time and the continuous updating limit, where Reinforcement Learning finds strategies that significantly improve over heuristics. In particular, we discuss how large decision times require enhanced knowledge of the flow, whereas for smaller $\tau$ all a priori heuristic strategies become Pareto optimal.