点云注册旨在估计两点云扫描之间的几何变换,在该点对应的估计中是其成功的关键。除了先前通过手工制作或学习的几何特征寻求对应的方法外,最近的点云注册方法还尝试应用RGB-D数据以实现更准确的对应关系。但是,有效地融合了这两种独特方式的几何和视觉信息并不是微不足道的,尤其是对于注册问题而言。在这项工作中,我们提出了一种新的几何感知视觉特征提取器(给出),该提取器采用多尺度的本地线性转换来逐步融合这两种方式,其中深度数据的几何特征是几何依赖于几何依赖的卷积内核来转换RGB数据的视觉功能。最终的视觉几何特征位于典型的特征空间中,由于几何变化引起的视觉差异可缓解,因此可以实现更可靠的对应关系。提出的给出的模块可以很容易地插入最近的RGB-D点云注册框架中。在3D匹配和扫描仪上进行的广泛实验表明,即使没有信件或姿势监督,我们的方法即使在没有通信或姿势的情况下也优于最先进的点云注册方法。该代码可在以下网址获得:https://github.com/514DNA/llt。
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少量学习,特别是几秒钟的图像分类,近年来受到了越来越多的关注,并目睹了重大进展。最近的一些研究暗示表明,许多通用技术或“诀窍”,如数据增强,预训练,知识蒸馏和自我监督,可能大大提高了几次学习方法的性能。此外,不同的作品可以采用不同的软件平台,不同的训练计划,不同的骨干架构以及甚至不同的输入图像大小,使得公平的比较困难,从业者与再现性斗争。为了解决这些情况,通过在Pytorch中的同一单个代码库中重新实施17个最新的框架,提出了几次射门学习(Libfewshot)的全面图书馆。此外,基于libfewshot,我们提供多个基准数据集的全面评估,其中包含多个骨干架构,以评估不同培训技巧的常见缺陷和效果。此外,鉴于近期对必要性或未培训机制的必要性怀疑,我们的评估结果表明,特别是当与预训练相结合时,仍然需要这种机制。我们希望我们的工作不仅可以降低初学者的障碍,可以在几次学习上工作,而且还消除了非动力技巧的影响,促进了几枪学习的内在研究。源代码可从https://github.com/rl-vig/libfewshot获取。
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鉴于输入面部照片,漫画生成的目标是生产风格化,夸张的漫画,与照片共享与相同的身份。它需要同时传输和形状夸张,具有丰富的多样性,同时保留输入的身份。为了解决这一具有挑战性的问题,我们提出了一种名为Multi-Warping GaN(MW-GAN)的新型框架,包括风格网络和几何网络,旨在分别进行样式传输和几何夸张。我们通过双向设计弥合图像的风格和地标之间的差距,并通过双向设计来生成具有任意样式和几何夸张的漫画,可以通过潜在代码或给定的随机采样来指定漫画样本。此外,我们对图像空间和地标空间施加身份保持损失,导致产生漫画的质量的巨大改善。实验表明,由MW-GaN产生的漫画具有比现有方法更好的质量。
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Theoretical properties of bilevel problems are well studied when the lower-level problem is strongly convex. In this work, we focus on bilevel optimization problems without the strong-convexity assumption. In these cases, we first show that the common local optimality measures such as KKT condition or regularization can lead to undesired consequences. Then, we aim to identify the mildest conditions that make bilevel problems tractable. We identify two classes of growth conditions on the lower-level objective that leads to continuity. Under these assumptions, we show that the local optimality of the bilevel problem can be defined via the Goldstein stationarity condition of the hyper-objective. We then propose the Inexact Gradient-Free Method (IGFM) to solve the bilevel problem, using an approximate zeroth order oracle that is of independent interest. Our non-asymptotic analysis demonstrates that the proposed method can find a $(\delta, \varepsilon)$ Goldstein stationary point for bilevel problems with a zeroth order oracle complexity that is polynomial in $d, 1/\delta$ and $1/\varepsilon$.
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Stance detection refers to the task of extracting the standpoint (Favor, Against or Neither) towards a target in given texts. Such research gains increasing attention with the proliferation of social media contents. The conventional framework of handling stance detection is converting it into text classification tasks. Deep learning models have already replaced rule-based models and traditional machine learning models in solving such problems. Current deep neural networks are facing two main challenges which are insufficient labeled data and information in social media posts and the unexplainable nature of deep learning models. A new pre-trained language model chatGPT was launched on Nov 30, 2022. For the stance detection tasks, our experiments show that ChatGPT can achieve SOTA or similar performance for commonly used datasets including SemEval-2016 and P-Stance. At the same time, ChatGPT can provide explanation for its own prediction, which is beyond the capability of any existing model. The explanations for the cases it cannot provide classification results are especially useful. ChatGPT has the potential to be the best AI model for stance detection tasks in NLP, or at least change the research paradigm of this field. ChatGPT also opens up the possibility of building explanatory AI for stance detection.
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Image manipulation localization aims at distinguishing forged regions from the whole test image. Although many outstanding prior arts have been proposed for this task, there are still two issues that need to be further studied: 1) how to fuse diverse types of features with forgery clues; 2) how to progressively integrate multistage features for better localization performance. In this paper, we propose a tripartite progressive integration network (TriPINet) for end-to-end image manipulation localization. First, we extract both visual perception information, e.g., RGB input images, and visual imperceptible features, e.g., frequency and noise traces for forensic feature learning. Second, we develop a guided cross-modality dual-attention (gCMDA) module to fuse different types of forged clues. Third, we design a set of progressive integration squeeze-and-excitation (PI-SE) modules to improve localization performance by appropriately incorporating multiscale features in the decoder. Extensive experiments are conducted to compare our method with state-of-the-art image forensics approaches. The proposed TriPINet obtains competitive results on several benchmark datasets.
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Graph Neural Networks (GNNs) have been a prevailing technique for tackling various analysis tasks on graph data. A key premise for the remarkable performance of GNNs relies on complete and trustworthy initial graph descriptions (i.e., node features and graph structure), which is often not satisfied since real-world graphs are often incomplete due to various unavoidable factors. In particular, GNNs face greater challenges when both node features and graph structure are incomplete at the same time. The existing methods either focus on feature completion or structure completion. They usually rely on the matching relationship between features and structure, or employ joint learning of node representation and feature (or structure) completion in the hope of achieving mutual benefit. However, recent studies confirm that the mutual interference between features and structure leads to the degradation of GNN performance. When both features and structure are incomplete, the mismatch between features and structure caused by the missing randomness exacerbates the interference between the two, which may trigger incorrect completions that negatively affect node representation. To this end, in this paper we propose a general GNN framework based on teacher-student distillation to improve the performance of GNNs on incomplete graphs, namely T2-GNN. To avoid the interference between features and structure, we separately design feature-level and structure-level teacher models to provide targeted guidance for student model (base GNNs, such as GCN) through distillation. Then we design two personalized methods to obtain well-trained feature and structure teachers. To ensure that the knowledge of the teacher model is comprehensively and effectively distilled to the student model, we further propose a dual distillation mode to enable the student to acquire as much expert knowledge as possible.
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Domain adaptation aims to transfer the knowledge acquired by models trained on (data-rich) source domains to (low-resource) target domains, for which a popular method is invariant representation learning. While they have been studied extensively for classification and regression problems, how they apply to ranking problems, where the data and metrics have a list structure, is not well understood. Theoretically, we establish a domain adaptation generalization bound for ranking under listwise metrics such as MRR and NDCG. The bound suggests an adaptation method via learning list-level domain-invariant feature representations, whose benefits are empirically demonstrated by unsupervised domain adaptation experiments on real-world ranking tasks, including passage reranking. A key message is that for domain adaptation, the representations should be analyzed at the same level at which the metric is computed, as we show that learning invariant representations at the list level is most effective for adaptation on ranking problems.
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Transformers have been essential to pretraining success in NLP. Other architectures have been used, but require attention layers to match benchmark accuracy. This work explores pretraining without attention. We test recently developed routing layers based on state-space models (SSM) and model architectures based on multiplicative gating. Used together these modeling choices have a large impact on pretraining accuracy. Empirically the proposed Bidirectional Gated SSM (BiGS) replicates BERT pretraining results without attention and can be extended to long-form pretraining of 4096 tokens without approximation.
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We present Hybrid Infused Reranking for Passages Retrieval (HYRR), a framework for training rerankers based on a hybrid of BM25 and neural retrieval models. Retrievers based on hybrid models have been shown to outperform both BM25 and neural models alone. Our approach exploits this improved performance when training a reranker, leading to a robust reranking model. The reranker, a cross-attention neural model, is shown to be robust to different first-stage retrieval systems, achieving better performance than rerankers simply trained upon the first-stage retrievers in the multi-stage systems. We present evaluations on a supervised passage retrieval task using MS MARCO and zero-shot retrieval tasks using BEIR. The empirical results show strong performance on both evaluations.
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