神经算法推理的基石是解决算法任务的能力,尤其是以一种概括分布的方式。尽管近年来,该领域的方法学改进激增,但它们主要集中在建立专家模型上。专业模型能够学习仅执行一种算法或具有相同控制流骨干的算法的集合。相反,在这里,我们专注于构建通才神经算法学习者 - 单个图形神经网络处理器,能够学习执行各种算法,例如分类,搜索,动态编程,路径触发和几何学。我们利用CLRS基准来凭经验表明,就像在感知领域的最新成功一样,通才算法学习者可以通过“合并”知识来构建。也就是说,只要我们能够在单任务制度中学习很好地执行它们,就可以以多任务的方式有效地学习算法。在此激励的基础上,我们为CLR提供了一系列改进,对CLR的输入表示,培训制度和处理器体系结构,将平均单任务性能提高了20%以上。然后,我们进行了多任务学习者的彻底消融,以利用这些改进。我们的结果表明,一位通才学习者有效地结合了专家模型所捕获的知识。
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计算文本表型是从临床注释中鉴定出患有某些疾病和特征的患者的实践。由于很少有用于机器学习的案例和域专家的数据注释需求,因此难以识别的罕见疾病要确定。我们提出了一种使用本体论和弱监督的方法,并具有来自双向变压器(例如BERT)的最新预训练的上下文表示。基于本体的框架包括两个步骤:(i)文本到umls,通过上下文将提及与统一医学语言系统(UMLS)中的概念链接到命名的实体识别和链接(NER+L)工具,SemeHR中提取表型。 ,以及具有自定义规则和上下文提及表示的弱监督; (ii)UMLS-to-to-ordo,将UMLS概念与孤子罕见疾病本体论(ORDO)中的罕见疾病相匹配。提出了弱监督的方法来学习一个表型确认模型,以改善链接的文本对umls,而没有域专家的注释数据。我们评估了来自美国和英国两个机构的三个出院摘要和放射学报告的临床数据集的方法。我们最好的弱监督方法获得了81.4%的精度和91.4%的召回,从模仿III出院摘要中提取罕见疾病UMLS表型。总体管道处理临床笔记可以表面罕见疾病病例,其中大部分在结构化数据(手动分配的ICD代码)中没有受到平衡。关于模仿III和NHS Tayside的放射学报告的结果与放电摘要一致。我们讨论了弱监督方法的有用性,并提出了未来研究的方向。
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临床编码是将患者健康记录中的医疗信息转换为结构化代码的任务,以便它们可用于统计分析。这是一项认知且耗时的任务,遵循标准过程,以达到高水平的一致性。自动化系统可以支持临床编码,以提高该过程的效率和准确性。我们介绍了自动临床编码的想法,并从人工智能(AI)和自然语言处理(NLP)(NLP)的角度总结了挑战,该文献是根据文献,我们在过去两年半(2019年末 - 2022年初)的项目经验),以及与苏格兰和英国的临床编码专家的讨论。我们的研究揭示了应用于临床编码的当前基于深度学习的方法与现实世界实践中的解释性和一致性之间的差距。基于知识的方法代表和推理了标准,可以解释的任务过程,可能需要将其纳入基于深度学习的临床编码方法中。尽管面临技术和组织的挑战,但自动化的临床编码是AI的一项有前途的任务。编码人员需要参与开发过程。在未来五年及以后,开发和部署基于AI的自动化系统需要实现很多目标。
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We derive a set of causal deep neural networks whose architectures are a consequence of tensor (multilinear) factor analysis. Forward causal questions are addressed with a neural network architecture composed of causal capsules and a tensor transformer. The former estimate a set of latent variables that represent the causal factors, and the latter governs their interaction. Causal capsules and tensor transformers may be implemented using shallow autoencoders, but for a scalable architecture we employ block algebra and derive a deep neural network composed of a hierarchy of autoencoders. An interleaved kernel hierarchy preprocesses the data resulting in a hierarchy of kernel tensor factor models. Inverse causal questions are addressed with a neural network that implements multilinear projection and estimates the causes of effects. As an alternative to aggressive bottleneck dimension reduction or regularized regression that may camouflage an inherently underdetermined inverse problem, we prescribe modeling different aspects of the mechanism of data formation with piecewise tensor models whose multilinear projections are well-defined and produce multiple candidate solutions. Our forward and inverse neural network architectures are suitable for asynchronous parallel computation.
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The existing methods for video anomaly detection mostly utilize videos containing identifiable facial and appearance-based features. The use of videos with identifiable faces raises privacy concerns, especially when used in a hospital or community-based setting. Appearance-based features can also be sensitive to pixel-based noise, straining the anomaly detection methods to model the changes in the background and making it difficult to focus on the actions of humans in the foreground. Structural information in the form of skeletons describing the human motion in the videos is privacy-protecting and can overcome some of the problems posed by appearance-based features. In this paper, we present a survey of privacy-protecting deep learning anomaly detection methods using skeletons extracted from videos. We present a novel taxonomy of algorithms based on the various learning approaches. We conclude that skeleton-based approaches for anomaly detection can be a plausible privacy-protecting alternative for video anomaly detection. Lastly, we identify major open research questions and provide guidelines to address them.
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Several self-supervised representation learning methods have been proposed for reinforcement learning (RL) with rich observations. For real-world applications of RL, recovering underlying latent states is crucial, particularly when sensory inputs contain irrelevant and exogenous information. In this work, we study how information bottlenecks can be used to construct latent states efficiently in the presence of task-irrelevant information. We propose architectures that utilize variational and discrete information bottlenecks, coined as RepDIB, to learn structured factorized representations. Exploiting the expressiveness bought by factorized representations, we introduce a simple, yet effective, bottleneck that can be integrated with any existing self-supervised objective for RL. We demonstrate this across several online and offline RL benchmarks, along with a real robot arm task, where we find that compressed representations with RepDIB can lead to strong performance improvements, as the learned bottlenecks help predict only the relevant state while ignoring irrelevant information.
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We propose reconstruction probing, a new analysis method for contextualized representations based on reconstruction probabilities in masked language models (MLMs). This method relies on comparing the reconstruction probabilities of tokens in a given sequence when conditioned on the representation of a single token that has been fully contextualized and when conditioned on only the decontextualized lexical prior of the model. This comparison can be understood as quantifying the contribution of contextualization towards reconstruction -- the difference in the reconstruction probabilities can only be attributed to the representational change of the single token induced by contextualization. We apply this analysis to three MLMs and find that contextualization boosts reconstructability of tokens that are close to the token being reconstructed in terms of linear and syntactic distance. Furthermore, we extend our analysis to finer-grained decomposition of contextualized representations, and we find that these boosts are largely attributable to static and positional embeddings at the input layer.
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Diffusion models have achieved justifiable popularity by attaining state-of-the-art performance in generating realistic objects from seemingly arbitrarily complex data distributions, including when conditioning generation on labels. Unfortunately, however, their iterative nature renders them very computationally inefficient during the sampling process. For the multi-class conditional generation problem, we propose a novel, structurally unique framework of diffusion models which are hierarchically branched according to the inherent relationships between classes. In this work, we demonstrate that branched diffusion models offer major improvements in efficiently generating samples from multiple classes. We also showcase several other advantages of branched diffusion models, including ease of extension to novel classes in a continual-learning setting, and a unique interpretability that offers insight into these generative models. Branched diffusion models represent an alternative paradigm to their traditional linear counterparts, and can have large impacts in how we use diffusion models for efficient generation, online learning, and scientific discovery.
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The widely studied task of Natural Language Inference (NLI) requires a system to recognize whether one piece of text is textually entailed by another, i.e. whether the entirety of its meaning can be inferred from the other. In current NLI datasets and models, textual entailment relations are typically defined on the sentence- or paragraph-level. However, even a simple sentence often contains multiple propositions, i.e. distinct units of meaning conveyed by the sentence. As these propositions can carry different truth values in the context of a given premise, we argue for the need to recognize the textual entailment relation of each proposition in a sentence individually. We propose PropSegmEnt, a corpus of over 35K propositions annotated by expert human raters. Our dataset structure resembles the tasks of (1) segmenting sentences within a document to the set of propositions, and (2) classifying the entailment relation of each proposition with respect to a different yet topically-aligned document, i.e. documents describing the same event or entity. We establish strong baselines for the segmentation and entailment tasks. Through case studies on summary hallucination detection and document-level NLI, we demonstrate that our conceptual framework is potentially useful for understanding and explaining the compositionality of NLI labels.
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People living with dementia often exhibit behavioural and psychological symptoms of dementia that can put their and others' safety at risk. Existing video surveillance systems in long-term care facilities can be used to monitor such behaviours of risk to alert the staff to prevent potential injuries or death in some cases. However, these behaviours of risk events are heterogeneous and infrequent in comparison to normal events. Moreover, analyzing raw videos can also raise privacy concerns. In this paper, we present two novel privacy-protecting video-based anomaly detection approaches to detect behaviours of risks in people with dementia. We either extracted body pose information as skeletons and use semantic segmentation masks to replace multiple humans in the scene with their semantic boundaries. Our work differs from most existing approaches for video anomaly detection that focus on appearance-based features, which can put the privacy of a person at risk and is also susceptible to pixel-based noise, including illumination and viewing direction. We used anonymized videos of normal activities to train customized spatio-temporal convolutional autoencoders and identify behaviours of risk as anomalies. We show our results on a real-world study conducted in a dementia care unit with patients with dementia, containing approximately 21 hours of normal activities data for training and 9 hours of data containing normal and behaviours of risk events for testing. We compared our approaches with the original RGB videos and obtained an equivalent area under the receiver operating characteristic curve performance of 0.807 for the skeleton-based approach and 0.823 for the segmentation mask-based approach. This is one of the first studies to incorporate privacy for the detection of behaviours of risks in people with dementia.
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