Reducing the quantity of annotations required for supervised training is vital when labels are scarce and costly. This reduction is especially important for semantic segmentation tasks involving 3D datasets that are often significantly smaller and more challenging to annotate than their image-based counterparts. Self-supervised pre-training on large unlabelled datasets is one way to reduce the amount of manual annotations needed. Previous work has focused on pre-training with point cloud data exclusively; this approach often requires two or more registered views. In the present work, we combine image and point cloud modalities, by first learning self-supervised image features and then using these features to train a 3D model. By incorporating image data, which is often included in many 3D datasets, our pre-training method only requires a single scan of a scene. We demonstrate that our pre-training approach, despite using single scans, achieves comparable performance to other multi-scan, point cloud-only methods.
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图像标题模型通常缺乏考虑用户兴趣的能力，通常默认为试图平衡可读性，信息性和信息过载的全局描述。另一方面，VQA模型通常缺乏提供长描述性答案的能力，同时期望文本问题非常精确。我们介绍一种控制图像标题应该专注于的概念的方法，使用称为指导文本的额外输入，该概念是指图像中的可接近或未放置的概念。我们的模型包括一个基于变换器的多模式编码器，它使用引导文本与全局和对象级别图像功能一起导出用于生成引导标题的早期融合表示。虽然在视觉基因组数据上培训的模型时，在使用自动对象标签的引导时具有适应良好的域的域中优势，但我们发现在概念标题上培训的引导标题模型概括为域外图像和引导文本。我们的人为评估结果表明，尝试野外引导的图像标题需要访问大，不受限制的域训练数据集，并且增加的样式分集（即使不增加唯一令牌的数量）是提高性能的关键因素。
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数值天气预报（NWP）和机器学习（ML）方法对于太阳能预测是流行的。但是，NWP模型具有多种可能的物理参数化，其需要特定于站点的NWP优化。当区域NWP模型与具有不同可能的参数化的全球气候模型一起使用时，这进一步复杂化。在该研究中，提出了一种替代方法，并评估了四种辐射模型。天气研究和预测（WRF）模型在全球和区域模式中运行，以提供太阳能辐照度的估计。然后使用ML后处理该估计以提供最终预测。该ML误差校正模型，来自WRF的归一化根均方误差高达40-50％。使用CAM，GFDL，新戈达德和RRTMG辐射模型获得的结果在此校正后可比，否定了WRF参数化调整的需求。还评估了包含附近地点和传感器数据的其他模型，后者是特别有前途的。
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我们提出了一种基于图形神经网络的图分算法。对于图表中的每个节点，网络输出每个分区的概率。图形神经网络由两个模块组成：嵌入阶段和分区阶段。首先通过最小化由光谱图理论的启发的损耗函数来训练嵌入阶段。分区模块通过损耗函数培训，该损耗函数对应于归一化切割的预期值。神经网络的两部分依赖于Sage卷积层和粗糙化粗糙匹配的图表。神经网络的多级结构受到多重级算法的启发。我们的方法概括了更大的图表，并且与Metis，Scotch和光谱分区相当的分区质量，与Metis和光谱分区相比具有较短的运行时。
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While the capabilities of autonomous systems have been steadily improving in recent years, these systems still struggle to rapidly explore previously unknown environments without the aid of GPS-assisted navigation. The DARPA Subterranean (SubT) Challenge aimed to fast track the development of autonomous exploration systems by evaluating their performance in real-world underground search-and-rescue scenarios. Subterranean environments present a plethora of challenges for robotic systems, such as limited communications, complex topology, visually-degraded sensing, and harsh terrain. The presented solution enables long-term autonomy with minimal human supervision by combining a powerful and independent single-agent autonomy stack, with higher level mission management operating over a flexible mesh network. The autonomy suite deployed on quadruped and wheeled robots was fully independent, freeing the human supervision to loosely supervise the mission and make high-impact strategic decisions. We also discuss lessons learned from fielding our system at the SubT Final Event, relating to vehicle versatility, system adaptability, and re-configurable communications.
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Attention mechanisms form a core component of several successful deep learning architectures, and are based on one key idea: ''The output depends only on a small (but unknown) segment of the input.'' In several practical applications like image captioning and language translation, this is mostly true. In trained models with an attention mechanism, the outputs of an intermediate module that encodes the segment of input responsible for the output is often used as a way to peek into the `reasoning` of the network. We make such a notion more precise for a variant of the classification problem that we term selective dependence classification (SDC) when used with attention model architectures. Under such a setting, we demonstrate various error modes where an attention model can be accurate but fail to be interpretable, and show that such models do occur as a result of training. We illustrate various situations that can accentuate and mitigate this behaviour. Finally, we use our objective definition of interpretability for SDC tasks to evaluate a few attention model learning algorithms designed to encourage sparsity and demonstrate that these algorithms help improve interpretability.
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This paper studies the quantization of heavy-tailed data in some fundamental statistical estimation problems, where the underlying distributions have bounded moments of some order. We propose to truncate and properly dither the data prior to a uniform quantization. Our major standpoint is that (near) minimax rates of estimation error are achievable merely from the quantized data produced by the proposed scheme. In particular, concrete results are worked out for covariance estimation, compressed sensing, and matrix completion, all agreeing that the quantization only slightly worsens the multiplicative factor. Besides, we study compressed sensing where both covariate (i.e., sensing vector) and response are quantized. Under covariate quantization, although our recovery program is non-convex because the covariance matrix estimator lacks positive semi-definiteness, all local minimizers are proved to enjoy near optimal error bound. Moreover, by the concentration inequality of product process and covering argument, we establish near minimax uniform recovery guarantee for quantized compressed sensing with heavy-tailed noise.
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Recent advances in deep learning have enabled us to address the curse of dimensionality (COD) by solving problems in higher dimensions. A subset of such approaches of addressing the COD has led us to solving high-dimensional PDEs. This has resulted in opening doors to solving a variety of real-world problems ranging from mathematical finance to stochastic control for industrial applications. Although feasible, these deep learning methods are still constrained by training time and memory. Tackling these shortcomings, Tensor Neural Networks (TNN) demonstrate that they can provide significant parameter savings while attaining the same accuracy as compared to the classical Dense Neural Network (DNN). In addition, we also show how TNN can be trained faster than DNN for the same accuracy. Besides TNN, we also introduce Tensor Network Initializer (TNN Init), a weight initialization scheme that leads to faster convergence with smaller variance for an equivalent parameter count as compared to a DNN. We benchmark TNN and TNN Init by applying them to solve the parabolic PDE associated with the Heston model, which is widely used in financial pricing theory.
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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.
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KL-regularized reinforcement learning from expert demonstrations has proved successful in improving the sample efficiency of deep reinforcement learning algorithms, allowing them to be applied to challenging physical real-world tasks. However, we show that KL-regularized reinforcement learning with behavioral reference policies derived from expert demonstrations can suffer from pathological training dynamics that can lead to slow, unstable, and suboptimal online learning. We show empirically that the pathology occurs for commonly chosen behavioral policy classes and demonstrate its impact on sample efficiency and online policy performance. Finally, we show that the pathology can be remedied by non-parametric behavioral reference policies and that this allows KL-regularized reinforcement learning to significantly outperform state-of-the-art approaches on a variety of challenging locomotion and dexterous hand manipulation tasks.
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