Active learning enables efficient model training by leveraging interactions between machine learning agents and human annotators. We study and propose a novel framework that formulates batch active learning from the sparse approximation's perspective. Our active learning method aims to find an informative subset from the unlabeled data pool such that the corresponding training loss function approximates its full data pool counterpart. We realize the framework as sparsity-constrained discontinuous optimization problems, which explicitly balance uncertainty and representation for large-scale applications and could be solved by greedy or proximal iterative hard thresholding algorithms. The proposed method can adapt to various settings, including both Bayesian and non-Bayesian neural networks. Numerical experiments show that our work achieves competitive performance across different settings with lower computational complexity.
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已经对蜘蛛/莎拉/风暴等方差降低技术进行了广泛的研究,以提高随机非凸优化的收敛速率,这些优化通常维护和更新跨迭代中单个函数的估计器序列。 {\如果我们需要在迭代中跟踪多个功能映射,但是只有访问$ \ Mathcal {o}的随机样品(1)$在每次迭代时$ functional映射?}在解决一个新兴的家族时,有一个重要的应用程序以$ \ sum_ {i = 1}^m f_i(g_i(\ mathbf {w}))的形式形式的耦合组合优化问题,其中$ g_i $可通过随机甲骨文访问$ g_i $。关键问题是跟踪和估计$ \ mathbf g(\ mathbf {w})=(g_1(\ mathbf {w}),\ ldots,g_m(\ mathbf {w})$ $ \ mathbf g(\ mathbf {w})$具有$ m $块,只允许探测$ \ mathcal {o}(1)$块才能达到其随机值和雅各布人。为了提高解决这些问题的复杂性,我们提出了一种新型随机方法,称为多块单个探针差异(MSVR)估计器,以跟踪$ \ mathbf g(\ mathbf {w})$的序列。它的灵感来自风暴,但引入了定制的误差校正术语,不仅可以减轻所选块的随机样品中的噪声,而且还可以减轻那些未进行采样的块中的噪声。在MSVR估计器的帮助下,我们开发了几种算法来解决上述组成问题,并在具有非convex/convex/convex/strank strank convex目标的各种设置中具有改善的复杂性。我们的结果在几个方面都改善了先前的结果,包括样本复杂性和对强凸参数的依赖。多任务深度AUC最大化的经验研究表明,使用新估计器的性能更好。
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现实世界的分类问题必须与域移位竞争,该域移动是部署模型的域之间的(潜在)不匹配以及收集训练数据的域。处理此类问题的方法必须指定域之间哪种结构与什么变化。一个自然的假设是,因果关系(结构)关系在所有领域都是不变的。然后,很容易学习仅取决于其因果父母的标签$ y $的预测指标。但是,许多现实世界中的问题是“反农产品”,因为$ y $是协变量$ x $的原因 - 在这种情况下,$ y $没有因果父母,而天真的因果不变性是没有用的。在本文中,我们研究了在特定的域转移概念下的表示形式学习,该概念既尊重因果不变性又自然处理“反毒物”结构。我们展示了如何利用域的共享因果结构来学习一个表示不变预测因子的表示,并且还允许在新域中快速适应。关键是将因果假设转化为学习原理,这些学习原理“不变”和“不稳定”特征。关于合成数据和现实世界数据的实验证明了所提出的学习算法的有效性。代码可在https://github.com/ybjiaang/actir上找到。
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5G毫米波(MMWAVE)信号与传播信道和传播环境具有固有的几何连接。因此,它们可用于共同本地化接收器并映射传播环境,该传播环境被称为同时定位和映射(SLAM)。5G SLAM中最重要的任务之一是处理测量模型的非线性。为了解决这个问题,现有的5G SLAM依赖于Sigma点或扩展卡尔曼滤波器,针对现有概率密度函数(PDF)线性化测量功能。在本文中,我们研究了关于后部PDF的测量功能的线性化,并将迭代后线性化滤波器实施到泊松多Bernoulli Slam滤波器中。仿真结果表明了所得SLAM过滤器的精度和精确改善。
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This paper focuses on designing efficient models with low parameters and FLOPs for dense predictions. Even though CNN-based lightweight methods have achieved stunning results after years of research, trading-off model accuracy and constrained resources still need further improvements. This work rethinks the essential unity of efficient Inverted Residual Block in MobileNetv2 and effective Transformer in ViT, inductively abstracting a general concept of Meta-Mobile Block, and we argue that the specific instantiation is very important to model performance though sharing the same framework. Motivated by this phenomenon, we deduce a simple yet efficient modern \textbf{I}nverted \textbf{R}esidual \textbf{M}obile \textbf{B}lock (iRMB) for mobile applications, which absorbs CNN-like efficiency to model short-distance dependency and Transformer-like dynamic modeling capability to learn long-distance interactions. Furthermore, we design a ResNet-like 4-phase \textbf{E}fficient \textbf{MO}del (EMO) based only on a series of iRMBs for dense applications. Massive experiments on ImageNet-1K, COCO2017, and ADE20K benchmarks demonstrate the superiority of our EMO over state-of-the-art methods, \eg, our EMO-1M/2M/5M achieve 71.5, 75.1, and 78.4 Top-1 that surpass \textbf{SoTA} CNN-/Transformer-based models, while trading-off the model accuracy and efficiency well.
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A recent study has shown a phenomenon called neural collapse in that the within-class means of features and the classifier weight vectors converge to the vertices of a simplex equiangular tight frame at the terminal phase of training for classification. In this paper, we explore the corresponding structures of the last-layer feature centers and classifiers in semantic segmentation. Based on our empirical and theoretical analysis, we point out that semantic segmentation naturally brings contextual correlation and imbalanced distribution among classes, which breaks the equiangular and maximally separated structure of neural collapse for both feature centers and classifiers. However, such a symmetric structure is beneficial to discrimination for the minor classes. To preserve these advantages, we introduce a regularizer on feature centers to encourage the network to learn features closer to the appealing structure in imbalanced semantic segmentation. Experimental results show that our method can bring significant improvements on both 2D and 3D semantic segmentation benchmarks. Moreover, our method ranks 1st and sets a new record (+6.8% mIoU) on the ScanNet200 test leaderboard. Code will be available at https://github.com/dvlab-research/Imbalanced-Learning.
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We aim to bridge the gap between our common-sense few-sample human learning and large-data machine learning. We derive a theory of human-like few-shot learning from von-Neuman-Landauer's principle. modelling human learning is difficult as how people learn varies from one to another. Under commonly accepted definitions, we prove that all human or animal few-shot learning, and major models including Free Energy Principle and Bayesian Program Learning that model such learning, approximate our theory, under Church-Turing thesis. We find that deep generative model like variational autoencoder (VAE) can be used to approximate our theory and perform significantly better than baseline models including deep neural networks, for image recognition, low resource language processing, and character recognition.
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Despite significant progress in object categorization, in recent years, a number of important challenges remain; mainly, the ability to learn from limited labeled data and to recognize object classes within large, potentially open, set of labels. Zero-shot learning is one way of addressing these challenges, but it has only been shown to work with limited sized class vocabularies and typically requires separation between supervised and unsupervised classes, allowing former to inform the latter but not vice versa. We propose the notion of vocabulary-informed learning to alleviate the above mentioned challenges and address problems of supervised, zero-shot, generalized zero-shot and open set recognition using a unified framework. Specifically, we propose a weighted maximum margin framework for semantic manifold-based recognition that incorporates distance constraints from (both supervised and unsupervised) vocabulary atoms. Distance constraints ensure that labeled samples are projected closer to their correct prototypes, in the embedding space, than to others. We illustrate that resulting model shows improvements in supervised, zero-shot, generalized zero-shot, and large open set recognition, with up to 310K class vocabulary on Animal with Attributes and ImageNet datasets.
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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.
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We consider infinite horizon Markov decision processes (MDPs) with fast-slow structure, meaning that certain parts of the state space move "fast" (and in a sense, are more influential) while other parts transition more "slowly." Such structure is common in real-world problems where sequential decisions need to be made at high frequencies, yet information that varies at a slower timescale also influences the optimal policy. Examples include: (1) service allocation for a multi-class queue with (slowly varying) stochastic costs, (2) a restless multi-armed bandit with an environmental state, and (3) energy demand response, where both day-ahead and real-time prices play a role in the firm's revenue. Models that fully capture these problems often result in MDPs with large state spaces and large effective time horizons (due to frequent decisions), rendering them computationally intractable. We propose an approximate dynamic programming algorithmic framework based on the idea of "freezing" the slow states, solving a set of simpler finite-horizon MDPs (the lower-level MDPs), and applying value iteration (VI) to an auxiliary MDP that transitions on a slower timescale (the upper-level MDP). We also extend the technique to a function approximation setting, where a feature-based linear architecture is used. On the theoretical side, we analyze the regret incurred by each variant of our frozen-state approach. Finally, we give empirical evidence that the frozen-state approach generates effective policies using just a fraction of the computational cost, while illustrating that simply omitting slow states from the decision modeling is often not a viable heuristic.
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