Text clustering and topic extraction are two important tasks in text mining. Usually, these two tasks are performed separately. For topic extraction to facilitate clustering, we can first project texts into a topic space and then perform a clustering algorithm to obtain clusters. To promote topic extraction by clustering, we can first obtain clusters with a clustering algorithm and then extract cluster-specific topics. However, this naive strategy ignores the fact that text clustering and topic extraction are strongly correlated and follow a chicken-and-egg relationship. Performing them separately fails to make them mutually benefit each other to achieve the best overall performance. In this paper, we propose an unsupervised text clustering and topic extraction framework (ClusTop) which integrates text clustering and topic extraction into a unified framework and can achieve high-quality clustering result and extract topics from each cluster simultaneously. Our framework includes four components: enhanced language model training, dimensionality reduction, clustering and topic extraction, where the enhanced language model can be viewed as a bridge between clustering and topic extraction. On one hand, it provides text embeddings with a strong cluster structure which facilitates effective text clustering; on the other hand, it pays high attention on the topic related words for topic extraction because of its self-attention architecture. Moreover, the training of enhanced language model is unsupervised. Experiments on two datasets demonstrate the effectiveness of our framework and provide benchmarks for different model combinations in this framework.
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了解出版物思想的起源和影响对于进行科学研究至关重要。但是,科学出版物的扩散使研究人员难以弄清所有相关文献的演变。为此,我们介绍了Ideareader,这是一种机器阅读系统,发现哪些论文最有可能激发或受到目标出版物的影响,并以自然语言总结了这些论文的想法。具体而言,Ideareader首先将目标出版物的参考和引用(一阶或高阶)和所获得的集群视为激发或受到目标出版物影响的主题。然后,它从每个集群中挑选出重要的论文来提取想法流的骨骼。最后,Ideareader会自动生成对每个主题中重要论文的文献综述。我们的系统可以帮助研究人员深入了解科学思想如何通过自动生成的调查和想法流的可视化来从目标出版物的引用引用。
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多变量时间序列(MTS)预测在智能应用的自动化和优化中起着重要作用。这是一个具有挑战性的任务,因为我们需要考虑复杂的变量依赖关系和可变间依赖关系。现有的作品仅在单个可变依赖项的帮助下学习时间模式。然而,许多真实世界MTS中有多种时间模式。单个可变间依赖项使模型更倾向于学习一种类型的突出和共享的时间模式。在本文中,我们提出了一个多尺度自适应图形神经网络(MOLDN)来解决上述问题。 MOLDN利用多尺度金字塔网络,以在不同的时间尺度上保留潜在的时间依赖关系。由于可变间依赖关系可以在不同的时间尺度下不同,所以自适应图学习模块被设计为在没有预先定义的前沿的情况下推断规模特定的可变依赖关系。鉴于多尺度特征表示和规模特定的可变间依赖关系,引入了一个多尺度的时间图神经网络,以共同模拟帧内依赖性和可变间依赖性。之后,我们开发一个尺度明智的融合模块,以在不同时间尺度上有效地促进协作,并自动捕获贡献的时间模式的重要性。四个真实数据集的实验表明,Magnn在各种设置上表明了最先进的方法。
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多变量时间序列(MTS)预测在许多智能应用中引起了很多关注。它不是一个琐碎的任务,因为我们需要考虑一个可变的依赖关系和可变间依赖关系。但是,现有的作品是针对特定场景设计的,需要很多域知识和专家努力,这难以在不同的场景之间传输。在本文中,我们提出了一种尺度意识的神经结构,用于MTS预测(SNAS4MTF)的搜索框架。多尺度分解模块将原始时间序列转换为多尺度子系列,可以保留多尺度的时间模式。自适应图形学习模块在没有任何先前知识的情况下,在不同的时间尺度下递送不同的变量间依赖关系。对于MTS预测,搜索空间旨在在每次尺度上捕获可变的可变依赖性和可变间依赖关系。在端到端框架中共同学习多尺度分解,自适应图学习和神经架构搜索模块。两个现实世界数据集的大量实验表明,与最先进的方法相比,SNAS4MTF实现了有希望的性能。
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时间序列预测是许多应用中的重大问题,例如,金融预测和业务优化。现代数据集可以具有多个相关时间序列,这些时间往往是通过全局(共享)规律和本地(特定)动态生成的。在本文中,我们寻求与DeepdGL的这种预测问题进行解决,这是一种深入预测模型,将动态与全球和局部时间模式脱颖而出。 DeepdGL采用编码器解码器架构,包括两个编码器,分别学习全局和本地时间模式,以及解码器以进行多步预测。具体地,为了模拟复杂的全局模式,引入了矢量量化(VQ)模块,允许全局特征编码器在所有时间序列中学习共享码本。为了模型多样化和异质局部模式,提出了一种由对比多地位编码(CMC)增强的自适应参数生成模块,以为每个单独的时间序列产生本地特征编码器的参数,这使得串联之间的相互信息最大化 - 具体的上下文变量和相应时间序列的长/短期表示。我们对几个现实世界数据集的实验表明DeepdGL优于现有的最先进的模型。
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Benefiting from the intrinsic supervision information exploitation capability, contrastive learning has achieved promising performance in the field of deep graph clustering recently. However, we observe that two drawbacks of the positive and negative sample construction mechanisms limit the performance of existing algorithms from further improvement. 1) The quality of positive samples heavily depends on the carefully designed data augmentations, while inappropriate data augmentations would easily lead to the semantic drift and indiscriminative positive samples. 2) The constructed negative samples are not reliable for ignoring important clustering information. To solve these problems, we propose a Cluster-guided Contrastive deep Graph Clustering network (CCGC) by mining the intrinsic supervision information in the high-confidence clustering results. Specifically, instead of conducting complex node or edge perturbation, we construct two views of the graph by designing special Siamese encoders whose weights are not shared between the sibling sub-networks. Then, guided by the high-confidence clustering information, we carefully select and construct the positive samples from the same high-confidence cluster in two views. Moreover, to construct semantic meaningful negative sample pairs, we regard the centers of different high-confidence clusters as negative samples, thus improving the discriminative capability and reliability of the constructed sample pairs. Lastly, we design an objective function to pull close the samples from the same cluster while pushing away those from other clusters by maximizing and minimizing the cross-view cosine similarity between positive and negative samples. Extensive experimental results on six datasets demonstrate the effectiveness of CCGC compared with the existing state-of-the-art algorithms.
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As one of the prevalent methods to achieve automation systems, Imitation Learning (IL) presents a promising performance in a wide range of domains. However, despite the considerable improvement in policy performance, the corresponding research on the explainability of IL models is still limited. Inspired by the recent approaches in explainable artificial intelligence methods, we proposed a model-agnostic explaining framework for IL models called R2RISE. R2RISE aims to explain the overall policy performance with respect to the frames in demonstrations. It iteratively retrains the black-box IL model from the randomized masked demonstrations and uses the conventional evaluation outcome environment returns as the coefficient to build an importance map. We also conducted experiments to investigate three major questions concerning frames' importance equality, the effectiveness of the importance map, and connections between importance maps from different IL models. The result shows that R2RISE successfully distinguishes important frames from the demonstrations.
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An increasing number of public datasets have shown a marked clinical impact on assessing anatomical structures. However, each of the datasets is small, partially labeled, and rarely investigates severe tumor subjects. Moreover, current models are limited to segmenting specific organs/tumors, which can not be extended to novel domains and classes. To tackle these limitations, we introduce embedding learned from Contrastive Language-Image Pre-training (CLIP) to segmentation models, dubbed the CLIP-Driven Universal Model. The Universal Model can better segment 25 organs and 6 types of tumors by exploiting the semantic relationship between abdominal structures. The model is developed from an assembly of 14 datasets with 3,410 CT scans and evaluated on 6,162 external CT scans from 3 datasets. We rank first on the public leaderboard of the Medical Segmentation Decathlon (MSD) and achieve the state-of-the-art results on Beyond The Cranial Vault (BTCV). Compared with dataset-specific models, the Universal Model is computationally more efficient (6x faster), generalizes better to CT scans from varying sites, and shows stronger transfer learning performance on novel tasks. The design of CLIP embedding enables the Universal Model to be easily extended to new classes without catastrophically forgetting the previously learned classes.
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Recent advances in self-supervised learning (SSL) in computer vision are primarily comparative, whose goal is to preserve invariant and discriminative semantics in latent representations by comparing siamese image views. However, the preserved high-level semantics do not contain enough local information, which is vital in medical image analysis (e.g., image-based diagnosis and tumor segmentation). To mitigate the locality problem of comparative SSL, we propose to incorporate the task of pixel restoration for explicitly encoding more pixel-level information into high-level semantics. We also address the preservation of scale information, a powerful tool in aiding image understanding but has not drawn much attention in SSL. The resulting framework can be formulated as a multi-task optimization problem on the feature pyramid. Specifically, we conduct multi-scale pixel restoration and siamese feature comparison in the pyramid. In addition, we propose non-skip U-Net to build the feature pyramid and develop sub-crop to replace multi-crop in 3D medical imaging. The proposed unified SSL framework (PCRLv2) surpasses its self-supervised counterparts on various tasks, including brain tumor segmentation (BraTS 2018), chest pathology identification (ChestX-ray, CheXpert), pulmonary nodule detection (LUNA), and abdominal organ segmentation (LiTS), sometimes outperforming them by large margins with limited annotations.
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Due to their ability to offer more comprehensive information than data from a single view, multi-view (multi-source, multi-modal, multi-perspective, etc.) data are being used more frequently in remote sensing tasks. However, as the number of views grows, the issue of data quality becomes more apparent, limiting the potential benefits of multi-view data. Although recent deep neural network (DNN) based models can learn the weight of data adaptively, a lack of research on explicitly quantifying the data quality of each view when fusing them renders these models inexplicable, performing unsatisfactorily and inflexible in downstream remote sensing tasks. To fill this gap, in this paper, evidential deep learning is introduced to the task of aerial-ground dual-view remote sensing scene classification to model the credibility of each view. Specifically, the theory of evidence is used to calculate an uncertainty value which describes the decision-making risk of each view. Based on this uncertainty, a novel decision-level fusion strategy is proposed to ensure that the view with lower risk obtains more weight, making the classification more credible. On two well-known, publicly available datasets of aerial-ground dual-view remote sensing images, the proposed approach achieves state-of-the-art results, demonstrating its effectiveness. The code and datasets of this article are available at the following address: https://github.com/gaopiaoliang/Evidential.
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