多元时间序列异常检测已在半监督的设置下进行了广泛的研究,其中需要所有具有正常实例的训练数据集。但是,准备这样的数据集非常费力,因为每个数据实例应完全保证是正常的。因此,希望在没有任何标签知识的情况下基于数据集探索基于数据集的多元时间序列异常检测方法。在本文中,我们提出了MTGFLOF,这是通过动态图和实体意识到的归一化流量进行多变量时间序列异常检测的无监督异常检测方法,仅依靠广泛接受的假设,即异常实例比正常情况表现出稀疏的密度。但是,实体之间的复杂相互依赖性和每个实体的不同固有特征对密度估计提出了重大挑战,更不用说基于估计的可能性分布来检测异常。为了解决这些问题,我们建议通过图结构学习模型来学习实体之间的相互关系,这有助于建模多元时间序列的准确分布。此外,考虑到各个实体的独特特征,开发了实体意识到的归一化流,以将每个实体描述为参数化的正态分布,从而产生细粒密度估计。结合了这两种策略,MTGFlowChieves出色的异常检测性能。进行了现实世界数据集的实验,表明MTGFLOW的表现分别超过了最先进的(SOTA),分别对SWAT和WADI数据集的实验分别高出5.0%和1.6%的AUROC。同样,通过单个实体贡献的异常得分,MTGFLOF可以为检测结果提供解释信息。
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在这封信中提出了一种新的基于触诊的切口检测策略,潜在地用于机器人气管术。引入触觉传感器以通过轻轻接触测量特定喉部区域中的组织硬度。提出了内核融合方法以将平方指数(SE)内核与ornstein-uhlenbeck(OU)内核组合,以弄清楚现有内核功能在这种情况下的缺点是不够最佳的。此外,我们进一步规则化探索因子和贪婪因子,并且触觉传感器的移动距离和机器人基准的旋转角度在切口定位过程中被认为是采集策略中的新因素。我们进行了模拟和物理实验,以比较新提出的算法 - 重新分配采集策略与热气检测中的能量限制(RASEC),具有当前的触诊的采集策略。结果表明,具有融合内核的建议采集策略可以通过最高算法性能成功定位切口(平均精度0.932,平均召回0.973,平均F1得分0.952)。在机器人触发过程中,累积移动距离减少了50%,累积旋转角度减少了71.4%,没有牺牲在综合性能能力中。因此,证明RASEC可以有效地表明喉部区域中的切割区域,大大降低了能量损失。
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基于度量学习的最近方法取得了很大镜头学习的巨大进步。然而,大多数人都仅限于图像级表示方式,这不能正确地处理课外变化和空间知识,从而产生不希望的性能。在本文中,我们提出了一个深度偏置纠正网络(DBRN)来充分利用特征表示结构中存在的空间信息。我们首先采用偏置整流模块来缓解由类内变化引起的不利影响。偏置纠正模块能够专注于通过给定不同权重的对分类更具判别的特征。为了充分利用培训数据,我们设计了一种模拟增强机制,可以使从支架组产生的原型更具代表性。为了验证我们方法的有效性,我们对各种流行的几次分类基准进行了广泛的实验,我们的方法可以优于最先进的方法。
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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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Deploying reliable deep learning techniques in interdisciplinary applications needs learned models to output accurate and ({even more importantly}) explainable predictions. Existing approaches typically explicate network outputs in a post-hoc fashion, under an implicit assumption that faithful explanations come from accurate predictions/classifications. We have an opposite claim that explanations boost (or even determine) classification. That is, end-to-end learning of explanation factors to augment discriminative representation extraction could be a more intuitive strategy to inversely assure fine-grained explainability, e.g., in those neuroimaging and neuroscience studies with high-dimensional data containing noisy, redundant, and task-irrelevant information. In this paper, we propose such an explainable geometric deep network dubbed as NeuroExplainer, with applications to uncover altered infant cortical development patterns associated with preterm birth. Given fundamental cortical attributes as network input, our NeuroExplainer adopts a hierarchical attention-decoding framework to learn fine-grained attentions and respective discriminative representations to accurately recognize preterm infants from term-born infants at term-equivalent age. NeuroExplainer learns the hierarchical attention-decoding modules under subject-level weak supervision coupled with targeted regularizers deduced from domain knowledge regarding brain development. These prior-guided constraints implicitly maximizes the explainability metrics (i.e., fidelity, sparsity, and stability) in network training, driving the learned network to output detailed explanations and accurate classifications. Experimental results on the public dHCP benchmark suggest that NeuroExplainer led to quantitatively reliable explanation results that are qualitatively consistent with representative neuroimaging studies.
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Medical image segmentation (MIS) is essential for supporting disease diagnosis and treatment effect assessment. Despite considerable advances in artificial intelligence (AI) for MIS, clinicians remain skeptical of its utility, maintaining low confidence in such black box systems, with this problem being exacerbated by low generalization for out-of-distribution (OOD) data. To move towards effective clinical utilization, we propose a foundation model named EvidenceCap, which makes the box transparent in a quantifiable way by uncertainty estimation. EvidenceCap not only makes AI visible in regions of uncertainty and OOD data, but also enhances the reliability, robustness, and computational efficiency of MIS. Uncertainty is modeled explicitly through subjective logic theory to gather strong evidence from features. We show the effectiveness of EvidenceCap in three segmentation datasets and apply it to the clinic. Our work sheds light on clinical safe applications and explainable AI, and can contribute towards trustworthiness in the medical domain.
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While inferring common actor states (such as position or velocity) is an important and well-explored task of the perception system aboard a self-driving vehicle (SDV), it may not always provide sufficient information to the SDV. This is especially true in the case of active emergency vehicles (EVs), where light-based signals also need to be captured to provide a full context. We consider this problem and propose a sequential methodology for the detection of active EVs, using an off-the-shelf CNN model operating at a frame level and a downstream smoother that accounts for the temporal aspect of flashing EV lights. We also explore model improvements through data augmentation and training with additional hard samples.
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Seismic data often undergoes severe noise due to environmental factors, which seriously affects subsequent applications. Traditional hand-crafted denoisers such as filters and regularizations utilize interpretable domain knowledge to design generalizable denoising techniques, while their representation capacities may be inferior to deep learning denoisers, which can learn complex and representative denoising mappings from abundant training pairs. However, due to the scarcity of high-quality training pairs, deep learning denoisers may sustain some generalization issues over various scenarios. In this work, we propose a self-supervised method that combines the capacities of deep denoiser and the generalization abilities of hand-crafted regularization for seismic data random noise attenuation. Specifically, we leverage the Self2Self (S2S) learning framework with a trace-wise masking strategy for seismic data denoising by solely using the observed noisy data. Parallelly, we suggest the weighted total variation (WTV) to further capture the horizontal local smooth structure of seismic data. Our method, dubbed as S2S-WTV, enjoys both high representation abilities brought from the self-supervised deep network and good generalization abilities of the hand-crafted WTV regularizer and the self-supervised nature. Therefore, our method can more effectively and stably remove the random noise and preserve the details and edges of the clean signal. To tackle the S2S-WTV optimization model, we introduce an alternating direction multiplier method (ADMM)-based algorithm. Extensive experiments on synthetic and field noisy seismic data demonstrate the effectiveness of our method as compared with state-of-the-art traditional and deep learning-based seismic data denoising methods.
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With the development of natural language processing techniques(NLP), automatic diagnosis of eye diseases using ophthalmology electronic medical records (OEMR) has become possible. It aims to evaluate the condition of both eyes of a patient respectively, and we formulate it as a particular multi-label classification task in this paper. Although there are a few related studies in other diseases, automatic diagnosis of eye diseases exhibits unique characteristics. First, descriptions of both eyes are mixed up in OEMR documents, with both free text and templated asymptomatic descriptions, resulting in sparsity and clutter of information. Second, OEMR documents contain multiple parts of descriptions and have long document lengths. Third, it is critical to provide explainability to the disease diagnosis model. To overcome those challenges, we present an effective automatic eye disease diagnosis framework, NEEDED. In this framework, a preprocessing module is integrated to improve the density and quality of information. Then, we design a hierarchical transformer structure for learning the contextualized representations of each sentence in the OEMR document. For the diagnosis part, we propose an attention-based predictor that enables traceable diagnosis by obtaining disease-specific information. Experiments on the real dataset and comparison with several baseline models show the advantage and explainability of our framework.
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Feature transformation for AI is an essential task to boost the effectiveness and interpretability of machine learning (ML). Feature transformation aims to transform original data to identify an optimal feature space that enhances the performances of a downstream ML model. Existing studies either combines preprocessing, feature selection, and generation skills to empirically transform data, or automate feature transformation by machine intelligence, such as reinforcement learning. However, existing studies suffer from: 1) high-dimensional non-discriminative feature space; 2) inability to represent complex situational states; 3) inefficiency in integrating local and global feature information. To fill the research gap, we formulate the feature transformation task as an iterative, nested process of feature generation and selection, where feature generation is to generate and add new features based on original features, and feature selection is to remove redundant features to control the size of feature space. Finally, we present extensive experiments and case studies to illustrate 24.7\% improvements in F1 scores compared with SOTAs and robustness in high-dimensional data.
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