We describe a Physics-Informed Neural Network (PINN) that simulates the flow induced by the astronomical tide in a synthetic port channel, with dimensions based on the Santos - S\~ao Vicente - Bertioga Estuarine System. PINN models aim to combine the knowledge of physical systems and data-driven machine learning models. This is done by training a neural network to minimize the residuals of the governing equations in sample points. In this work, our flow is governed by the Navier-Stokes equations with some approximations. There are two main novelties in this paper. First, we design our model to assume that the flow is periodic in time, which is not feasible in conventional simulation methods. Second, we evaluate the benefit of resampling the function evaluation points during training, which has a near zero computational cost and has been verified to improve the final model, especially for small batch sizes. Finally, we discuss some limitations of the approximations used in the Navier-Stokes equations regarding the modeling of turbulence and how it interacts with PINNs.
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当使用基于视觉的方法对被占用和空的空地之间的单个停车位进行分类时,人类专家通常需要注释位置,并标记包含目标停车场中收集的图像的训练集,以微调系统。我们建议研究三种注释类型(多边形,边界框和固定尺寸的正方形),提供停车位的不同数据表示。理由是阐明手工艺注释精度和模型性能之间的最佳权衡。我们还调查了在目标停车场微调预训练型号所需的带注释的停车位数。使用PKLOT数据集使用的实验表明,使用低精度注释(例如固定尺寸的正方形),可以将模型用少于1,000个标记的样品微调到目标停车场。
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研究人员通常会采用数值方法来理解和预测海洋动力学,这是掌握环境现象的关键任务。在地形图很复杂,有关基础过程的知识不完整或应用程序至关重要的情况下,此类方法可能不适合。另一方面,如果观察到海洋动力学,则可以通过最近的机器学习方法来利用它们。在本文中,我们描述了一种数据驱动的方法,可以预测环境变量,例如巴西东南海岸的Santos-Sao Vicente-Bertioga estuarine系统的当前速度和海面高度。我们的模型通过连接最新的序列模型(LSTM和Transformers)以及关系模型(图神经网络)来利用时间和空间归纳偏见,以学习时间特征和空间特征,观察站点之间共享的关系。我们将结果与桑托斯运营预测系统(SOFS)进行比较。实验表明,我们的模型可以实现更好的结果,同时保持灵活性和很少的领域知识依赖性。
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深度学习体系结构已在不同领域(例如医学,农业和安全)取得了有希望的结果。但是,由于培训过程中所需的大型收藏品,在许多实际应用中使用这些强大的技术变得具有挑战性。几项作品通过提出可以更少学习更多知识的策略,例如弱和半监督的学习方法来克服它来克服它。由于这些方法通常无法解决对对抗性例子的记忆和敏感性,因此本文介绍了三种深度度量学习方法与混音相结合,以实现不完整的监督场景。我们表明,在这种情况下,指标学习中的一些最新方法可能无法很好地工作。此外,所提出的方法在不同数据集中的表现优于大多数。
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对SQL查询的自然语言问题的翻译引起了不断增长的关注,特别是与变压器和类似的语言模型有关。大量技术朝向英语;在这项工作中,我们在葡萄牙语中给出输入问题时,我们将调查到SQL的翻译。为此,我们适用于最先进的工具和资源。我们通过依赖于多语言BART模型来更改RAT-SQL + GAP系统(我们用其他语言模型报告测试),我们制作了蜘蛛数据集的翻译版本。我们的实验暴露了非英语语言的目标时出现的有趣现象;特别是,即使需要单个目标语言,它更好地用原始和翻译训练数据集训练。这种多语言BART模型用双尺寸训练数据集(英语和葡萄牙语)进行了微调,实现了83%的基线,为葡萄牙语测试数据集推断出来。这项调查可以帮助其他研究人员以不同于英语的语言产生导致的机器学习。我们的多语言现时版本的RAT-SQL +间隙和数据可用,开放为MRAT-SQL + GAP:https://github.com/c4ai/gap-text2sql
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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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Recent years have seen a proliferation of research on adversarial machine learning. Numerous papers demonstrate powerful algorithmic attacks against a wide variety of machine learning (ML) models, and numerous other papers propose defenses that can withstand most attacks. However, abundant real-world evidence suggests that actual attackers use simple tactics to subvert ML-driven systems, and as a result security practitioners have not prioritized adversarial ML defenses. Motivated by the apparent gap between researchers and practitioners, this position paper aims to bridge the two domains. We first present three real-world case studies from which we can glean practical insights unknown or neglected in research. Next we analyze all adversarial ML papers recently published in top security conferences, highlighting positive trends and blind spots. Finally, we state positions on precise and cost-driven threat modeling, collaboration between industry and academia, and reproducible research. We believe that our positions, if adopted, will increase the real-world impact of future endeavours in adversarial ML, bringing both researchers and practitioners closer to their shared goal of improving the security of ML systems.
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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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