最近出现了许多子图增强图神经网络(GNN),可证明增强了标准(消息通话)GNN的表达能力。但是,对这些方法之间的相互关系和weisfeiler层次结构的关系有限。此外,当前的方法要么使用给定尺寸的所有子图,要随机均匀地对其进行采样,或者使用手工制作的启发式方法,而不是学习以数据驱动的方式选择子图。在这里,我们提供了一种统一的方法来研究此类体系结构,通过引入理论框架并扩展了亚图增强GNN的已知表达结果。具体而言,我们表明,增加子图的大小总是会增加表达能力,并通过将它们与已建立的$ k \ text { - } \ Mathsf {Wl} $ hierArchy联系起来,从而更好地理解其局限性。此外,我们还使用最近通过复杂的离散概率分布进行反向传播的方法探索了学习对子图进行采样的不同方法。从经验上讲,我们研究了不同子图增强的GNN的预测性能,表明我们的数据驱动体系结构与非DATA驱动的亚图增强图形神经网络相比,在标准基准数据集上提高了对标准基准数据集的预测准确性,同时减少了计算时间。
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尽管(消息通话)图形神经网络在图形或一般关系数据上近似置换量等函数方面具有明显的局限性,但更具表现力的高阶图神经网络不会扩展到大图。他们要么在$ k $ - 订单张量子上操作,要么考虑所有$ k $ - 节点子图,这意味着在内存需求中对$ k $的指数依赖,并且不适合图形的稀疏性。通过为图同构问题引入新的启发式方法,我们设计了一类通用的,置换式的图形网络,与以前的体系结构不同,该网络在表达性和可伸缩性之间提供了细粒度的控制,并适应了图的稀疏性。这些体系结构与监督节点和图形级别的标准高阶网络以及回归体系中的标准高阶图网络相比大大减少了计算时间,同时在预测性能方面显着改善了标准图神经网络和图形内核体系结构。
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近年来,图形神经网络(GNNS)被出现为一个强大的神经结构,以学习在监督的端到端时尚中的节点和图表的矢量表示。到目前为止,只有经验评估GNNS - 显示有希望的结果。以下工作从理论的角度调查了GNN,并将它们与1美元 - 二维韦斯美犬 - Leman Graph同构Heuristic(1美元-WL)相关联。我们表明GNNS在区分非同义(子)图表中,GNN具有与1美元-WL相同的表现力。因此,这两种算法也具有相同的缺点。基于此,我们提出了GNN的概括,所谓的$ k $ -dimensional gnns($ k $ -gnns),这可以考虑多个尺度的高阶图结构。这些高阶结构在社交网络和分子图的表征中起重要作用。我们的实验评估证实了我们的理论调查结果,并确认了更高阶信息在图形分类和回归的任务中有用。
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This paper presents a comprehensive survey of low-light image and video enhancement. We begin with the challenging mixed over-/under-exposed images, which are under-performed by existing methods. To this end, we propose two variants of the SICE dataset named SICE_Grad and SICE_Mix. Next, we introduce Night Wenzhou, a large-scale, high-resolution video dataset, to address the issue of the lack of a low-light video dataset that discount the use of low-light image enhancement (LLIE) to videos. The Night Wenzhou dataset is challenging since it consists of fast-moving aerial scenes and streetscapes with varying illuminations and degradation. We conduct extensive key technique analysis and experimental comparisons for representative LLIE approaches using these newly proposed datasets and the current benchmark datasets. Finally, we address unresolved issues and propose future research topics for the LLIE community.
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We investigate data-driven texture modeling via analysis and synthesis with generative adversarial networks. For network training and testing, we have compiled a diverse set of spatially homogeneous textures, ranging from stochastic to regular. We adopt StyleGAN3 for synthesis and demonstrate that it produces diverse textures beyond those represented in the training data. For texture analysis, we propose GAN inversion using a novel latent domain reconstruction consistency criterion for synthesized textures, and iterative refinement with Gramian loss for real textures. We propose perceptual procedures for evaluating network capabilities, exploring the global and local behavior of latent space trajectories, and comparing with existing texture analysis-synthesis techniques.
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Recent advances in deep learning research, such as transformers, have bolstered the ability for automated agents to generate creative texts similar to those that a human would write. By default, transformer decoders can only generate new text with respect to previously generated text. The output distribution of candidate tokens at any position is conditioned on previously selected tokens using a self-attention mechanism to emulate the property of autoregression. This is inherently limiting for tasks such as controllable story generation where it may be necessary to condition on future plot events when writing a story. In this work, we propose Future Sight, a method for finetuning a pretrained generative transformer on the task of future conditioning. Transformer decoders are typically pretrained on the task of completing a context, one token at a time, by means of self-attention. Future Sight additionally enables a decoder to attend to an encoded future plot event. This motivates the decoder to expand on the context in a way that logically concludes with the provided future. During inference, the future plot event can be written by a human author to steer the narrative being generated in a certain direction. We evaluate the efficacy of our approach on a story generation task with human evaluators.
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Transformer-based models have gained large popularity and demonstrated promising results in long-term time-series forecasting in recent years. In addition to learning attention in time domain, recent works also explore learning attention in frequency domains (e.g., Fourier domain, wavelet domain), given that seasonal patterns can be better captured in these domains. In this work, we seek to understand the relationships between attention models in different time and frequency domains. Theoretically, we show that attention models in different domains are equivalent under linear conditions (i.e., linear kernel to attention scores). Empirically, we analyze how attention models of different domains show different behaviors through various synthetic experiments with seasonality, trend and noise, with emphasis on the role of softmax operation therein. Both these theoretical and empirical analyses motivate us to propose a new method: TDformer (Trend Decomposition Transformer), that first applies seasonal-trend decomposition, and then additively combines an MLP which predicts the trend component with Fourier attention which predicts the seasonal component to obtain the final prediction. Extensive experiments on benchmark time-series forecasting datasets demonstrate that TDformer achieves state-of-the-art performance against existing attention-based models.
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Boundary conditions (BCs) are important groups of physics-enforced constraints that are necessary for solutions of Partial Differential Equations (PDEs) to satisfy at specific spatial locations. These constraints carry important physical meaning, and guarantee the existence and the uniqueness of the PDE solution. Current neural-network based approaches that aim to solve PDEs rely only on training data to help the model learn BCs implicitly. There is no guarantee of BC satisfaction by these models during evaluation. In this work, we propose Boundary enforcing Operator Network (BOON) that enables the BC satisfaction of neural operators by making structural changes to the operator kernel. We provide our refinement procedure, and demonstrate the satisfaction of physics-based BCs, e.g. Dirichlet, Neumann, and periodic by the solutions obtained by BOON. Numerical experiments based on multiple PDEs with a wide variety of applications indicate that the proposed approach ensures satisfaction of BCs, and leads to more accurate solutions over the entire domain. The proposed correction method exhibits a (2X-20X) improvement over a given operator model in relative $L^2$ error (0.000084 relative $L^2$ error for Burgers' equation).
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Training a neural network requires choosing a suitable learning rate, involving a trade-off between speed and effectiveness of convergence. While there has been considerable theoretical and empirical analysis of how large the learning rate can be, most prior work focuses only on late-stage training. In this work, we introduce the maximal initial learning rate $\eta^{\ast}$ - the largest learning rate at which a randomly initialized neural network can successfully begin training and achieve (at least) a given threshold accuracy. Using a simple approach to estimate $\eta^{\ast}$, we observe that in constant-width fully-connected ReLU networks, $\eta^{\ast}$ demonstrates different behavior to the maximum learning rate later in training. Specifically, we find that $\eta^{\ast}$ is well predicted as a power of $(\text{depth} \times \text{width})$, provided that (i) the width of the network is sufficiently large compared to the depth, and (ii) the input layer of the network is trained at a relatively small learning rate. We further analyze the relationship between $\eta^{\ast}$ and the sharpness $\lambda_{1}$ of the network at initialization, indicating that they are closely though not inversely related. We formally prove bounds for $\lambda_{1}$ in terms of $(\text{depth} \times \text{width})$ that align with our empirical results.
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We introduce OPEND, a benchmark for learning how to use a hand to open cabinet doors or drawers in a photo-realistic and physics-reliable simulation environment driven by language instruction. To solve the task, we propose a multi-step planner composed of a deep neural network and rule-base controllers. The network is utilized to capture spatial relationships from images and understand semantic meaning from language instructions. Controllers efficiently execute the plan based on the spatial and semantic understanding. We evaluate our system by measuring its zero-shot performance in test data set. Experimental results demonstrate the effectiveness of decision planning by our multi-step planner for different hands, while suggesting that there is significant room for developing better models to address the challenge brought by language understanding, spatial reasoning, and long-term manipulation. We will release OPEND and host challenges to promote future research in this area.
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