固有频率的降低通常用作结构健康监测(SHM)目的的损坏指标。但是,操作和环境条件的波动,边界条件的变化以及名义相同结构之间的微小差异也会影响刚度,从而产生模仿或掩盖损坏的频率变化。这种可变性限制了SHM技术的实际实施和概括。这项工作的目的是研究正常变异的效果,并确定解释产生不确定性的方法。这项工作考虑了从四个健康的全尺度复合直升机叶片收集的振动数据。叶片名义上是相同的,但叶片是不同的,并且叶片之间的材料特性和几何形状略有差异,导致频率响应函数的显着差异,这是整个输入空间中四个独立的轨迹。在本文中,使用高斯工艺(OMGP)的重叠混合物来生成标签并量化直升机叶片的正常条件频率响应数据的不确定性。使用基于人群的方法,OMGP模型提供了称为形式的通用表示形式,以表征叶片的正常状况。然后将其他模拟数据与该形式进行比较,并使用边缘样式新颖性指数评估损伤。
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在过去的三十年中,结构性健康监测(SHM)一直是一个活跃的研究领域,并且在此期间积累了许多关键进展,如文献所示。但是,由于损害状态数据,操作和环境波动,可重复性问题以及边界条件的变化,SHM仍然面临挑战。这些问题在被捕获的功能中是不一致的,并且可能会对实际实施产生巨大影响,但更重要的是对技术的概括。基于人群的SHM旨在通过使用从相似结构组收集的数据对缺失信息进行建模和传输信息来解决其中的一些问题。在这项工作中,从四个健康的,名义上相同的全尺度复合直升机叶片收集了振动数据。制造差异(例如,几何形状和/或材料属性的略有差异),在其结构动力学上显示为可变性,这对于基于振动数据的机器学习而对SHM来说可能非常有问题。这项工作旨在通过使用高斯过程的混合物来定义叶片的频率响应函数的通用模型来解决此变异性。
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Data deprivation, or the lack of easily available and actionable information on the well-being of individuals, is a significant challenge for the developing world and an impediment to the design and operationalization of policies intended to alleviate poverty. In this paper we explore the suitability of data derived from OpenStreetMap to proxy for the location of two crucial public services: schools and health clinics. Thanks to the efforts of thousands of digital humanitarians, online mapping repositories such as OpenStreetMap contain millions of records on buildings and other structures, delineating both their location and often their use. Unfortunately much of this data is locked in complex, unstructured text rendering it seemingly unsuitable for classifying schools or clinics. We apply a scalable, unsupervised learning method to unlabeled OpenStreetMap building data to extract the location of schools and health clinics in ten countries in Africa. We find the topic modeling approach greatly improves performance versus reliance on structured keys alone. We validate our results by comparing schools and clinics identified by our OSM method versus those identified by the WHO, and describe OSM coverage gaps more broadly.
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对行人行为的预测对于完全自主车辆安全有效地在繁忙的城市街道上驾驶至关重要。未来的自治车需要适应混合条件,不仅具有技术还是社会能力。随着更多算法和数据集已经开发出预测行人行为,这些努力缺乏基准标签和估计行人的时间动态意图变化的能力,提供了对交互场景的解释,以及具有社会智能的支持算法。本文提出并分享另一个代表数据集,称为Iupui-CSRC行人位于意图(PSI)数据,除了综合计算机视觉标签之外,具有两种创新标签。第一部小说标签是在自助式车辆前面交叉的行人的动态意图变化,从24个司机中实现了不同的背景。第二个是在估计行人意图并在交互期间预测其行为时对驾驶员推理过程的基于文本的解释。这些创新标签可以启用几个计算机视觉任务,包括行人意图/行为预测,车辆行人互动分割和用于可解释算法的视频到语言映射。发布的数据集可以从根本上从根本上改善行人行为预测模型的发展,并开发社会智能自治车,以有效地与行人进行互动。 DataSet已被不同的任务进行评估,并已释放到公众访问。
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Variational inference uses optimization, rather than integration, to approximate the marginal likelihood, and thereby the posterior, in a Bayesian model. Thanks to advances in computational scalability made in the last decade, variational inference is now the preferred choice for many high-dimensional models and large datasets. This tutorial introduces variational inference from the parametric perspective that dominates these recent developments, in contrast to the mean-field perspective commonly found in other introductory texts.
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Knowledge graphs (KG) have served as the key component of various natural language processing applications. Commonsense knowledge graphs (CKG) are a special type of KG, where entities and relations are composed of free-form text. However, previous works in KG completion and CKG completion suffer from long-tail relations and newly-added relations which do not have many know triples for training. In light of this, few-shot KG completion (FKGC), which requires the strengths of graph representation learning and few-shot learning, has been proposed to challenge the problem of limited annotated data. In this paper, we comprehensively survey previous attempts on such tasks in the form of a series of methods and applications. Specifically, we first introduce FKGC challenges, commonly used KGs, and CKGs. Then we systematically categorize and summarize existing works in terms of the type of KGs and the methods. Finally, we present applications of FKGC models on prediction tasks in different areas and share our thoughts on future research directions of FKGC.
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Few Shot Instance Segmentation (FSIS) requires models to detect and segment novel classes with limited several support examples. In this work, we explore a simple yet unified solution for FSIS as well as its incremental variants, and introduce a new framework named Reference Twice (RefT) to fully explore the relationship between support/query features based on a Transformer-like framework. Our key insights are two folds: Firstly, with the aid of support masks, we can generate dynamic class centers more appropriately to re-weight query features. Secondly, we find that support object queries have already encoded key factors after base training. In this way, the query features can be enhanced twice from two aspects, i.e., feature-level and instance-level. In particular, we firstly design a mask-based dynamic weighting module to enhance support features and then propose to link object queries for better calibration via cross-attention. After the above steps, the novel classes can be improved significantly over our strong baseline. Additionally, our new framework can be easily extended to incremental FSIS with minor modification. When benchmarking results on the COCO dataset for FSIS, gFSIS, and iFSIS settings, our method achieves a competitive performance compared to existing approaches across different shots, e.g., we boost nAP by noticeable +8.2/+9.4 over the current state-of-the-art FSIS method for 10/30-shot. We further demonstrate the superiority of our approach on Few Shot Object Detection. Code and model will be available.
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Unsupervised domain adaptation (UDA) for semantic segmentation is a promising task freeing people from heavy annotation work. However, domain discrepancies in low-level image statistics and high-level contexts compromise the segmentation performance over the target domain. A key idea to tackle this problem is to perform both image-level and feature-level adaptation jointly. Unfortunately, there is a lack of such unified approaches for UDA tasks in the existing literature. This paper proposes a novel UDA pipeline for semantic segmentation that unifies image-level and feature-level adaptation. Concretely, for image-level domain shifts, we propose a global photometric alignment module and a global texture alignment module that align images in the source and target domains in terms of image-level properties. For feature-level domain shifts, we perform global manifold alignment by projecting pixel features from both domains onto the feature manifold of the source domain; and we further regularize category centers in the source domain through a category-oriented triplet loss and perform target domain consistency regularization over augmented target domain images. Experimental results demonstrate that our pipeline significantly outperforms previous methods. In the commonly tested GTA5$\rightarrow$Cityscapes task, our proposed method using Deeplab V3+ as the backbone surpasses previous SOTA by 8%, achieving 58.2% in mIoU.
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The development of social media user stance detection and bot detection methods rely heavily on large-scale and high-quality benchmarks. However, in addition to low annotation quality, existing benchmarks generally have incomplete user relationships, suppressing graph-based account detection research. To address these issues, we propose a Multi-Relational Graph-Based Twitter Account Detection Benchmark (MGTAB), the first standardized graph-based benchmark for account detection. To our knowledge, MGTAB was built based on the largest original data in the field, with over 1.55 million users and 130 million tweets. MGTAB contains 10,199 expert-annotated users and 7 types of relationships, ensuring high-quality annotation and diversified relations. In MGTAB, we extracted the 20 user property features with the greatest information gain and user tweet features as the user features. In addition, we performed a thorough evaluation of MGTAB and other public datasets. Our experiments found that graph-based approaches are generally more effective than feature-based approaches and perform better when introducing multiple relations. By analyzing experiment results, we identify effective approaches for account detection and provide potential future research directions in this field. Our benchmark and standardized evaluation procedures are freely available at: https://github.com/GraphDetec/MGTAB.
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The performance of inertial navigation systems is largely dependent on the stable flow of external measurements and information to guarantee continuous filter updates and bind the inertial solution drift. Platforms in different operational environments may be prevented at some point from receiving external measurements, thus exposing their navigation solution to drift. Over the years, a wide variety of works have been proposed to overcome this shortcoming, by exploiting knowledge of the system current conditions and turning it into an applicable source of information to update the navigation filter. This paper aims to provide an extensive survey of information aided navigation, broadly classified into direct, indirect, and model aiding. Each approach is described by the notable works that implemented its concept, use cases, relevant state updates, and their corresponding measurement models. By matching the appropriate constraint to a given scenario, one will be able to improve the navigation solution accuracy, compensate for the lost information, and uncover certain internal states, that would otherwise remain unobservable.
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