Principal Component Analysis (PCA) and its exponential family extensions have three components: observations, latents and parameters of a linear transformation. We consider a generalised setting where the canonical parameters of the exponential family are a nonlinear transformation of the latents. We show explicit relationships between particular neural network architectures and the corresponding statistical models. We find that deep equilibrium models -- a recently introduced class of implicit neural networks -- solve maximum a-posteriori (MAP) estimates for the latents and parameters of the transformation. Our analysis provides a systematic way to relate activation functions, dropout, and layer structure, to statistical assumptions about the observations, thus providing foundational principles for unsupervised DEQs. For hierarchical latents, individual neurons can be interpreted as nodes in a deep graphical model. Our DEQ feature maps are end-to-end differentiable, enabling fine-tuning for downstream tasks.
translated by 谷歌翻译
我们考虑了个性化新闻推荐的问题,每个用户都以顺序消费新闻。现有的个性化新闻推荐方法的重点是利用用户兴趣,而忽略了推荐中的探索,从而导致反馈循环并长期损害了建议质量。我们基于上下文土匪推荐策略,自然可以解决剥削 - 探索权衡取舍。主要挑战是探索大规模项目空间并利用不确定性的深层表示的计算效率。我们提出了一个两阶段的分层主题,新的深层上下文强盗框架,以在有许多新闻项目时有效地学习用户偏好。我们为用户和新闻使用深度学习表示形式,并将神经上限限制(UCB)策略推广到广义添加剂UCB和BILINEAR UCB。大规模新闻建议数据集的经验结果表明,我们提出的政策是有效的,并且表现优于基线匪徒政策。
translated by 谷歌翻译
我们考虑了持续的武装匪徒问题,在汇总反馈下的固定预算范围内推荐最好的武器。这是通过精确奖励不可能或获得昂贵的应用程序的激励,而可提供聚合奖励或反馈,例如子集的平均值。我们假设它们来自高斯进程并提出高斯工艺乐观优化(GPOO)算法来限制一组奖励功能。我们自适应地构造一个树的树,作为臂空间的子集,在那里反馈是节点代表的聚合奖励。我们为建议武器的汇总反馈提出了一个新的简单遗憾概念。我们为所提出的算法提供理论分析,并将单点反馈恢复为特殊情况。我们说明了GPoo并将其与模拟数据的相关算法进行比较。
translated by 谷歌翻译
傅里叶神经运营商(FNO)是一种基于学习的方法,用于有效地模拟部分微分方程。我们提出了分解的傅立叶神经运营商(F-FNO),允许与更深的网络更好地推广。通过仔细组合傅里叶分解,跨所有层,Markov属性和残差连接的共享内核积分运算符,F-FNOS在Navier-Stokes基准数据集的最动力设置上达到六倍的误差。我们表明我们的模型保持了2%的错误率,同时仍然比数值求解器更快地运行幅度,即使问题设置扩展到包括诸如粘度和时变力的附加上下文,也是如此。这使得与相同的预制神经网络能够模拟巨大不同的条件。
translated by 谷歌翻译
我们介绍了一系列成对随机梯度估计,用于期望的梯度,与日志衍生物特征有关,但涉及样本之间的成对交互。我们的新估计器的最简单示例被称为基本特技估计器,从A)引入并逼近基于微积分的基本定理,或B)将Reparameterisisisisisation技巧应用于无限扰动下的隐式参数化的整体表示参数。从前透视我们概括到再现内核希尔伯特空间表示,从上面提到的成对交互中产生了位置参数,产生了我们的代表技巧估计器。得到的估计器是无偏见的,并显示用于与日志导数估计器相比提供有用信息的独立组件。我们提供了进一步的新颖理论分析,其进一步表征了新技术所提供的差异。有希望的分析和数值例子证实了新估算器后面的理论和直觉。
translated by 谷歌翻译
This paper introduces the use of evolutionary algorithms for solving differential equations. The solution is obtained by optimizing a deep neural network whose loss function is defined by the residual terms from the differential equations. Recent studies have used stochastic gradient descent (SGD) variants to train these physics-informed neural networks (PINNs), but these methods can struggle to find accurate solutions due to optimization challenges. When solving differential equations, it is important to find the globally optimum parameters of the network, rather than just finding a solution that works well during training. SGD only searches along a single gradient direction, so it may not be the best approach for training PINNs with their accompanying complex optimization landscapes. In contrast, evolutionary algorithms perform a parallel exploration of different solutions in order to avoid getting stuck in local optima and can potentially find more accurate solutions. However, evolutionary algorithms can be slow, which can make them difficult to use in practice. To address this, we provide a set of five benchmark problems with associated performance metrics and baseline results to support the development of evolutionary algorithms for enhanced PINN training. As a baseline, we evaluate the performance and speed of using the widely adopted Covariance Matrix Adaptation Evolution Strategy (CMA-ES) for solving PINNs. We provide the loss and training time for CMA-ES run on TensorFlow, and CMA-ES and SGD run on JAX (with GPU acceleration) for the five benchmark problems. Our results show that JAX-accelerated evolutionary algorithms, particularly CMA-ES, can be a useful approach for solving differential equations. We hope that our work will support the exploration and development of alternative optimization algorithms for the complex task of optimizing PINNs.
translated by 谷歌翻译
我们提出蒙版频率建模(MFM),这是一种基于统一的基于频域的方法,用于自我监督的视觉模型预训练。在本文中,我们将视角转移到了频域中,而不是将蒙版令牌随机插入到空间域中的输入嵌入。具体而言,MFM首先掩盖了输入图像的一部分频率分量,然后预测频谱上的缺失频率。我们的关键见解是,由于沉重的空间冗余,预测频域中的屏蔽组件更理想地揭示了基础图像模式,而不是预测空间域中的掩盖斑块。我们的发现表明,通过对蒙版和预测策略的正确配置,高频组件中的结构信息和低频对应物中的低级统计信息都有用。 MFM首次证明,对于VIT和CNN,即使没有使用以下内容,简单的非叙事框架也可以学习有意义的表示形式:(i)额外的数据,(ii)额外的模型,(iii)蒙版令牌。与最近的蒙版图像建模方法相比,对成像网和几个鲁棒性基准的实验结果表明,MFM的竞争性能和高级鲁棒性。此外,我们还全面研究了从统一的频率角度来表示经典图像恢复任务对表示学习的有效性,并揭示了他们与MFM方法的有趣关系。项目页面:https://www.mmlab-ntu.com/project/mfm/index.html。
translated by 谷歌翻译
对比的自我监督学习在很大程度上缩小了对想象成的预先训练的差距。然而,它的成功高度依赖于想象成的以对象形象,即相同图像的不同增强视图对应于相同的对象。当预先训练在具有许多物体的更复杂的场景图像上,如此重种策划约束会立即不可行。为了克服这一限制,我们介绍了对象级表示学习(ORL),这是一个新的自我监督的学习框架迈向场景图像。我们的主要洞察力是利用图像级自我监督的预培训作为发现对象级语义对应之前的,从而实现了从场景图像中学习的对象级表示。对Coco的广泛实验表明,ORL显着提高了自我监督学习在场景图像上的性能,甚至超过了在几个下游任务上的监督Imagenet预训练。此外,当可用更加解标的场景图像时,ORL提高了下游性能,证明其在野外利用未标记数据的巨大潜力。我们希望我们的方法可以激励未来的研究从场景数据的更多通用无人监督的代表。
translated by 谷歌翻译
对比度学习最近在无监督的视觉表示学习中显示出巨大的潜力。在此轨道中的现有研究主要集中于图像内不变性学习。学习通常使用丰富的图像内变换来构建正对,然后使用对比度损失最大化一致性。相反,相互影响不变性的优点仍然少得多。利用图像间不变性的一个主要障碍是,尚不清楚如何可靠地构建图像间的正对,并进一步从它们中获得有效的监督,因为没有配对注释可用。在这项工作中,我们提出了一项全面的实证研究,以更好地了解从三个主要组成部分的形象间不变性学习的作用:伪标签维护,采样策略和决策边界设计。为了促进这项研究,我们引入了一个统一的通用框架,该框架支持无监督的内部和间形内不变性学习的整合。通过精心设计的比较和分析,揭示了多个有价值的观察结果:1)在线标签收敛速度比离线标签更快; 2)半硬性样品比硬否定样品更可靠和公正; 3)一个不太严格的决策边界更有利于形象间的不变性学习。借助所有获得的食谱,我们的最终模型(即InterCLR)对多个标准基准测试的最先进的内图内不变性学习方法表现出一致的改进。我们希望这项工作将为设计有效的无监督间歇性不变性学习提供有用的经验。代码:https://github.com/open-mmlab/mmselfsup。
translated by 谷歌翻译
Panoptic Part Segmentation (PPS) unifies panoptic segmentation and part segmentation into one task. Previous works utilize separated approaches to handle thing, stuff, and part predictions without shared computation and task association. We aim to unify these tasks at the architectural level, designing the first end-to-end unified framework named Panoptic-PartFormer. Moreover, we find the previous metric PartPQ biases to PQ. To handle both issues, we make the following contributions: Firstly, we design a meta-architecture that decouples part feature and things/stuff feature, respectively. We model things, stuff, and parts as object queries and directly learn to optimize all three forms of prediction as a unified mask prediction and classification problem. We term our model as Panoptic-PartFormer. Secondly, we propose a new metric Part-Whole Quality (PWQ) to better measure such task from both pixel-region and part-whole perspectives. It can also decouple the error for part segmentation and panoptic segmentation. Thirdly, inspired by Mask2Former, based on our meta-architecture, we propose Panoptic-PartFormer++ and design a new part-whole cross attention scheme to further boost part segmentation qualities. We design a new part-whole interaction method using masked cross attention. Finally, the extensive ablation studies and analysis demonstrate the effectiveness of both Panoptic-PartFormer and Panoptic-PartFormer++. Compared with previous Panoptic-PartFormer, our Panoptic-PartFormer++ achieves 2% PartPQ and 3% PWQ improvements on the Cityscapes PPS dataset and 5% PartPQ on the Pascal Context PPS dataset. On both datasets, Panoptic-PartFormer++ achieves new state-of-the-art results with a significant cost drop of 70% on GFlops and 50% on parameters. Our models can serve as a strong baseline and aid future research in PPS. Code will be available.
translated by 谷歌翻译