精确分割是分析心脏周期语义信息并使用心血管信号捕获异常的至关重要的第一步。但是,在深层语义分割领域,通常会单方面与数据的个体属性相混淆。走向心血管信号,准周期性是要学习的必不可少的特征,被视为形态学属性(AM)和节奏(AR)的合成。我们的关键见解是在深度表示的生成过程中抑制对AM或AR的过度依赖性。为了解决这个问题,我们建立了一个结构性因果模型,作为分别自定义AM和AR的干预方法的基础。在本文中,我们提出了对比性因果干预(CCI),以在框架级对比框架下形成一种新颖的训练范式。干预可以消除单个属性带来的隐式统计偏见,并导致更客观的表示。我们对QRS位置和心脏声音分割的受控条件进行了全面的实验。最终结果表明,我们的方法显然可以将QRS位置的性能提高高达0.41%,心脏声音分段为2.73%。该方法的效率推广到多个数据库和嘈杂的信号。
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为了以计算有效的方式部署深层模型,经常使用模型量化方法。此外,由于新的硬件支持混合的位算术操作,最近对混合精度量化(MPQ)的研究开始通过搜索网络中不同层和模块的优化位低宽,从而完全利用表示的能力。但是,先前的研究主要是在使用强化学习,神经体系结构搜索等的昂贵方案中搜索MPQ策略,或者简单地利用部分先验知识来进行位于刻度分配,这可能是有偏见和优势的。在这项工作中,我们提出了一种新颖的随机量化量化(SDQ)方法,该方法可以在更灵活,更全球优化的空间中自动学习MPQ策略,并具有更平滑的梯度近似。特别是,可区分的位宽参数(DBP)被用作相邻位意选择之间随机量化的概率因素。在获取最佳MPQ策略之后,我们将进一步训练网络使用熵感知的bin正则化和知识蒸馏。我们广泛评估了不同硬件(GPU和FPGA)和数据集的多个网络的方法。 SDQ的表现优于所有最先进的混合或单个精度量化,甚至比较低的位置量化,甚至比各种重新网络和Mobilenet家族的全精度对应物更好,这表明了我们方法的有效性和优势。
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很少有语义细分旨在识别一个看不见类别的对象区域,只有几个带注释的示例作为监督。几次分割的关键是在支持图像和查询图像之间建立牢固的语义关系,并防止过度拟合。在本文中,我们提出了一个有效的多相似性超关联网络(MSHNET),以解决几个射击语义分割问题。在MSHNET中,我们提出了一种新的生成原型相似性(GPS),与余弦相似性可以在支持图像和查询图像之间建立牢固的语义关系。基于全局特征的本地生成的原型相似性在逻辑上与基于本地特征的全局余弦相似性互补,并且可以通过同时使用两个相似性来更全面地表达查询图像和受支持图像之间的关系。此外,我们提出了MSHNET中的对称合并块(SMB),以有效合并多层,多弹射和多相似性超相关特征。 MSHNET是基于相似性而不是特定类别特征而构建的,这些特征可以实现更一般的统一性并有效地减少过度拟合。在两个基准的语义分割数据集Pascal-5i和Coco-20i上,MSHNET在1次和5次语义分段任务上实现了新的最先进的表演。
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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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Rankings are widely collected in various real-life scenarios, leading to the leakage of personal information such as users' preferences on videos or news. To protect rankings, existing works mainly develop privacy protection on a single ranking within a set of ranking or pairwise comparisons of a ranking under the $\epsilon$-differential privacy. This paper proposes a novel notion called $\epsilon$-ranking differential privacy for protecting ranks. We establish the connection between the Mallows model (Mallows, 1957) and the proposed $\epsilon$-ranking differential privacy. This allows us to develop a multistage ranking algorithm to generate synthetic rankings while satisfying the developed $\epsilon$-ranking differential privacy. Theoretical results regarding the utility of synthetic rankings in the downstream tasks, including the inference attack and the personalized ranking tasks, are established. For the inference attack, we quantify how $\epsilon$ affects the estimation of the true ranking based on synthetic rankings. For the personalized ranking task, we consider varying privacy preferences among users and quantify how their privacy preferences affect the consistency in estimating the optimal ranking function. Extensive numerical experiments are carried out to verify the theoretical results and demonstrate the effectiveness of the proposed synthetic ranking algorithm.
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In this work, we focus on instance-level open vocabulary segmentation, intending to expand a segmenter for instance-wise novel categories without mask annotations. We investigate a simple yet effective framework with the help of image captions, focusing on exploiting thousands of object nouns in captions to discover instances of novel classes. Rather than adopting pretrained caption models or using massive caption datasets with complex pipelines, we propose an end-to-end solution from two aspects: caption grounding and caption generation. In particular, we devise a joint Caption Grounding and Generation (CGG) framework based on a Mask Transformer baseline. The framework has a novel grounding loss that performs explicit and implicit multi-modal feature alignments. We further design a lightweight caption generation head to allow for additional caption supervision. We find that grounding and generation complement each other, significantly enhancing the segmentation performance for novel categories. We conduct extensive experiments on the COCO dataset with two settings: Open Vocabulary Instance Segmentation (OVIS) and Open Set Panoptic Segmentation (OSPS). The results demonstrate the superiority of our CGG framework over previous OVIS methods, achieving a large improvement of 6.8% mAP on novel classes without extra caption data. Our method also achieves over 15% PQ improvements for novel classes on the OSPS benchmark under various settings.
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Temporal sentence grounding (TSG) aims to identify the temporal boundary of a specific segment from an untrimmed video by a sentence query. All existing works first utilize a sparse sampling strategy to extract a fixed number of video frames and then conduct multi-modal interactions with query sentence for reasoning. However, we argue that these methods have overlooked two indispensable issues: 1) Boundary-bias: The annotated target segment generally refers to two specific frames as corresponding start and end timestamps. The video downsampling process may lose these two frames and take the adjacent irrelevant frames as new boundaries. 2) Reasoning-bias: Such incorrect new boundary frames also lead to the reasoning bias during frame-query interaction, reducing the generalization ability of model. To alleviate above limitations, in this paper, we propose a novel Siamese Sampling and Reasoning Network (SSRN) for TSG, which introduces a siamese sampling mechanism to generate additional contextual frames to enrich and refine the new boundaries. Specifically, a reasoning strategy is developed to learn the inter-relationship among these frames and generate soft labels on boundaries for more accurate frame-query reasoning. Such mechanism is also able to supplement the absent consecutive visual semantics to the sampled sparse frames for fine-grained activity understanding. Extensive experiments demonstrate the effectiveness of SSRN on three challenging datasets.
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Brain midline shift (MLS) is one of the most critical factors to be considered for clinical diagnosis and treatment decision-making for intracranial hemorrhage. Existing computational methods on MLS quantification not only require intensive labeling in millimeter-level measurement but also suffer from poor performance due to their dependence on specific landmarks or simplified anatomical assumptions. In this paper, we propose a novel semi-supervised framework to accurately measure the scale of MLS from head CT scans. We formulate the MLS measurement task as a deformation estimation problem and solve it using a few MLS slices with sparse labels. Meanwhile, with the help of diffusion models, we are able to use a great number of unlabeled MLS data and 2793 non-MLS cases for representation learning and regularization. The extracted representation reflects how the image is different from a non-MLS image and regularization serves an important role in the sparse-to-dense refinement of the deformation field. Our experiment on a real clinical brain hemorrhage dataset has achieved state-of-the-art performance and can generate interpretable deformation fields.
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It is crucial to evaluate the quality and determine the optimal number of clusters in cluster analysis. In this paper, the multi-granularity characterization of the data set is carried out to obtain the hyper-balls. The cluster internal evaluation index based on hyper-balls(HCVI) is defined. Moreover, a general method for determining the optimal number of clusters based on HCVI is proposed. The proposed methods can evaluate the clustering results produced by the several classic methods and determine the optimal cluster number for data sets containing noises and clusters with arbitrary shapes. The experimental results on synthetic and real data sets indicate that the new index outperforms existing ones.
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Normalizing flow is a class of deep generative models for efficient sampling and density estimation. In practice, the flow often appears as a chain of invertible neural network blocks; to facilitate training, existing works have regularized flow trajectories and designed special network architectures. The current paper develops a neural ODE flow network inspired by the Jordan-Kinderleherer-Otto (JKO) scheme, which allows efficient block-wise training of the residual blocks and avoids inner loops of score matching or variational learning. As the JKO scheme unfolds the dynamic of gradient flow, the proposed model naturally stacks residual network blocks one-by-one, reducing the memory load and difficulty of performing end-to-end training of deep flow networks. We also develop adaptive time reparameterization of the flow network with a progressive refinement of the trajectory in probability space, which improves the model training efficiency and accuracy in practice. Using numerical experiments with synthetic and real data, we show that the proposed JKO-iFlow model achieves similar or better performance in generating new samples compared with existing flow and diffusion models at a significantly reduced computational and memory cost.
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