结构磁共振成像研究表明,大脑解剖异常与早产儿的认知缺陷有关。脑成熟和几何特征可以与机器学习模型一起使用,以预测以后的神经发育缺陷。但是,传统的机器学习模型将遭受较大的功能比率(即大量功能,但少数实例/样本)。合奏学习是一种范式,从战略上生成和集成了机器学习分类器库,并已成功地用于各种预测性建模问题,以提高模型性能。属性(即功能)包装方法是最常用的特征分区方案,它随机和反复从整个功能集中绘制特征子集。尽管属性装袋方法可以有效地降低特征维度以处理大型功能与实用比率,但它缺乏对域知识和特征之间的潜在关系的考虑。在这项研究中,我们提出了一种新型的本体论引导属性分区(OAP)方法,以通过考虑特征之间的特定于域的关系来更好地绘制特征子集。有了更好的分区功能子集,我们开发了一个合奏学习框架,该框架称为OAP汇总学习(OAP-EL)。我们应用了OAP-EL,以使用定量脑成熟和在非常早产的年龄在期限年龄获得的定量脑成熟和几何特征来预测2岁年龄的认知缺陷。我们证明,提出的OAP-EL方法显着优于同行集合学习和传统的机器学习方法。
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The previous fine-grained datasets mainly focus on classification and are often captured in a controlled setup, with the camera focusing on the objects. We introduce the first Fine-Grained Vehicle Detection (FGVD) dataset in the wild, captured from a moving camera mounted on a car. It contains 5502 scene images with 210 unique fine-grained labels of multiple vehicle types organized in a three-level hierarchy. While previous classification datasets also include makes for different kinds of cars, the FGVD dataset introduces new class labels for categorizing two-wheelers, autorickshaws, and trucks. The FGVD dataset is challenging as it has vehicles in complex traffic scenarios with intra-class and inter-class variations in types, scale, pose, occlusion, and lighting conditions. The current object detectors like yolov5 and faster RCNN perform poorly on our dataset due to a lack of hierarchical modeling. Along with providing baseline results for existing object detectors on FGVD Dataset, we also present the results of a combination of an existing detector and the recent Hierarchical Residual Network (HRN) classifier for the FGVD task. Finally, we show that FGVD vehicle images are the most challenging to classify among the fine-grained datasets.
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Over the years, Machine Learning models have been successfully employed on neuroimaging data for accurately predicting brain age. Deviations from the healthy brain aging pattern are associated to the accelerated brain aging and brain abnormalities. Hence, efficient and accurate diagnosis techniques are required for eliciting accurate brain age estimations. Several contributions have been reported in the past for this purpose, resorting to different data-driven modeling methods. Recently, deep neural networks (also referred to as deep learning) have become prevalent in manifold neuroimaging studies, including brain age estimation. In this review, we offer a comprehensive analysis of the literature related to the adoption of deep learning for brain age estimation with neuroimaging data. We detail and analyze different deep learning architectures used for this application, pausing at research works published to date quantitatively exploring their application. We also examine different brain age estimation frameworks, comparatively exposing their advantages and weaknesses. Finally, the review concludes with an outlook towards future directions that should be followed by prospective studies. The ultimate goal of this paper is to establish a common and informed reference for newcomers and experienced researchers willing to approach brain age estimation by using deep learning models
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声学事件是具有定义明确的光谱特征的声音,可以与生成它们的物理对象相关联。声学场景是没有特定时间顺序的此类声学事件的集合。鉴于事件和场景之间的这种自然联系,一个普遍的信念是,对事件进行分类的能力必须有助于对场景的分类。这导致了几项努力,试图在声学事件标签(AET)和声学场景分类(ASC)上做得很好,使用多任务网络。但是,在这些努力中,一项任务的改进不能保证另一个任务的改善,这表明ASC和AET之间会有张力。目前尚不清楚AET的改进是否转化为ASC的改进。我们通过一项广泛的实证研究来探索这一难题,并表明在某些条件下,使用AET作为多任务网络中的辅助任务始终提高ASC的性能。此外,ASC性能进一步改善了AET数据集大小,并且对事件的选择或AET数据集中的事件数量不敏感。我们得出的结论是,ASC性能的这种改善来自使用AET的正规化效果,而不是网络提高了在声学事件之间识别的能力。
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本文展示了alphaRARDEN:一个自治的多种植花园,在1.5米×3.0米的物理测试平台中撒上和灌溉生物植物。alphanArden使用架空相机和传感器来跟踪植物分布和土壤水分。我们模拟个体植物生长和平面动态,以培训选择行动以最大化叶片覆盖和多样性的政策。对于自主修剪,alphanarden使用两个定制的修剪工具和训练有素的神经网络来检测紫杉角。我们为四个60天的花园周期提供了结果。结果表明,alphaRARARDEN可以自主地实现0.96个归一化多样性,在循环峰值期间保持0.86的平均冠层覆盖率。可以在https://github.com/berkeleyautomation/alpharden找到代码,数据集和补充材料。
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We present Habitat, a platform for research in embodied artificial intelligence (AI). Habitat enables training embodied agents (virtual robots) in highly efficient photorealistic 3D simulation. Specifically, Habitat consists of: (i) Habitat-Sim: a flexible, high-performance 3D simulator with configurable agents, sensors, and generic 3D dataset handling. Habitat-Sim is fast -when rendering a scene from Matterport3D, it achieves several thousand frames per second (fps) running single-threaded, and can reach over 10,000 fps multi-process on a single GPU. (ii) Habitat-API: a modular high-level library for end-toend development of embodied AI algorithms -defining tasks (e.g. navigation, instruction following, question answering), configuring, training, and benchmarking embodied agents.These large-scale engineering contributions enable us to answer scientific questions requiring experiments that were till now impracticable or 'merely' impractical. Specifically, in the context of point-goal navigation: (1) we revisit the comparison between learning and SLAM approaches from two recent works [20,16] and find evidence for the opposite conclusion -that learning outperforms SLAM if scaled to an order of magnitude more experience than previous investigations, and (2) we conduct the first cross-dataset generalization experiments {train, test} × {Matterport3D, Gibson} for multiple sensors {blind, RGB, RGBD, D} and find that only agents with depth (D) sensors generalize across datasets. We hope that our open-source platform and these findings will advance research in embodied AI.
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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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