深度学习算法的最新进展为解决许多医学图像分析问题带来了重大好处。培训深度学习模型通常需要具有专家标记注释的大型数据集。但是,获取专家标记的注释不仅昂贵,而且主观,容易出错,并且观察者内部变异性会引入标签。由于解剖学的模棱两可,使用深度学习模型来细分医学图像时,这尤其是一个问题。基于图像的医学诊断工具使用经过不正确分段标签训练的深度学习模型可以导致错误的诊断和治疗建议。与单评论注释相比,多评价者注释可能更适合于使用小型培训集的深度学习模型进行训练。本文的目的是开发和评估一种基于MRI中病变特征的多评价者注释和解剖学知识来生成概率标签的方法,以及一种使用概率的标签使用归一化活动性损失作为A的病变特征的解剖学知识,以训练分割模型”。耐噪声损失的功能。通过将17个膝盖MRI扫描的二进制基础真理进行比较,以评估该模型,以用于临床分割和检测骨髓病变(BML)。该方法与二进制跨透镜损失函数相比,该方法成功提高了精度14,召回22和骰子得分8%。总体而言,这项工作的结果表明,使用软标签的拟议归一化主动损失成功地减轻了嘈杂标签的影响。
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对骨关节炎(OA)的磁共振成像(MRI)扫描的客观评估可以解决当前OA评估的局限性。 OA客观评估是必需的骨,软骨和关节液的分割。大多数提出的分割方法都不执行实例分割,并且遭受了类不平衡问题。这项研究部署了蒙版R-CNN实例分割并改进了IT(改进的面罩R-CNN(IMASKRCNN)),以获得与OA相关组织的更准确的广义分割。该方法的训练和验证是使用骨关节炎倡议(OAI)数据集的500次MRI膝盖和有症状髋关节OA患者的97次MRI扫描进行的。掩盖R-CNN的三个修改产生了iMaskRCNN:添加第二个Roialigned块,在掩码标先中添加了额外的解码器层,并通过跳过连接将它们连接起来。使用Hausdorff距离,骰子评分和变异系数(COV)评估结果。与面膜RCNN相比,iMaskRCNN导致骨骼和软骨分割的改善,这表明股骨的骰子得分从95%增加到98%,胫骨的95%到97%,股骨软骨的71%至80%,81%和81%胫骨软骨的%至82%。对于积液检测,iMaskRCNN 72%比MaskRCNN 71%改善了骰子。 Reader1和Mask R-CNN(0.33),Reader1和ImaskRCNN(0.34),Reader2和Mask R-CNN(0.22),Reader2和iMaskRCNN(0.29)之间的积液检测的COV值(0.34),读取器2和mask r-CNN(0.22)接近COV之间,表明人类读者与蒙版R-CNN和ImaskRCNN之间的一致性很高。蒙版R-CNN和ImaskRCNN可以可靠,同时提取与OA有关的不同规模的关节组织,从而为OA的自动评估构成基础。 iMaskRCNN结果表明,修改改善了边缘周围的网络性能。
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解释性学者通过手动采样文档,应用代码以及将代码精炼和整理成类别,直到出现有意义的主题,从而从文本语料库中产生知识。鉴于大量的语料库,机器学习可以帮助扩展此数据采样和分析,但先前的研究表明,专家通常关注算法可能破坏或推动解释性奖学金。我们采用以人为本的设计方法来解决围绕机器辅助解释性研究的关注,以构建学术研究,该研究将机器中的集群算法纳入了脚手架解释性文本分析。随着学者将代码应用于文档和完善它们,所得编码的模式用作结构化元数据,该元数据限制了从语料库推断出的层次文档和单词簇。这些集群的交互式可视化可以帮助学者们战略性地对文档进行进一步的洞察力进行洞察力。 Scholastic证明了采用熟悉隐喻的以人为中心的算法设计和可视化如何通过交互式主题建模和文档群集来支持归纳和解释性研究方法。
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While the brain connectivity network can inform the understanding and diagnosis of developmental dyslexia, its cause-effect relationships have not yet enough been examined. Employing electroencephalography signals and band-limited white noise stimulus at 4.8 Hz (prosodic-syllabic frequency), we measure the phase Granger causalities among channels to identify differences between dyslexic learners and controls, thereby proposing a method to calculate directional connectivity. As causal relationships run in both directions, we explore three scenarios, namely channels' activity as sources, as sinks, and in total. Our proposed method can be used for both classification and exploratory analysis. In all scenarios, we find confirmation of the established right-lateralized Theta sampling network anomaly, in line with the temporal sampling framework's assumption of oscillatory differences in the Theta and Gamma bands. Further, we show that this anomaly primarily occurs in the causal relationships of channels acting as sinks, where it is significantly more pronounced than when only total activity is observed. In the sink scenario, our classifier obtains 0.84 and 0.88 accuracy and 0.87 and 0.93 AUC for the Theta and Gamma bands, respectively.
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There are multiple scales of abstraction from which we can describe the same image, depending on whether we are focusing on fine-grained details or a more global attribute of the image. In brain mapping, learning to automatically parse images to build representations of both small-scale features (e.g., the presence of cells or blood vessels) and global properties of an image (e.g., which brain region the image comes from) is a crucial and open challenge. However, most existing datasets and benchmarks for neuroanatomy consider only a single downstream task at a time. To bridge this gap, we introduce a new dataset, annotations, and multiple downstream tasks that provide diverse ways to readout information about brain structure and architecture from the same image. Our multi-task neuroimaging benchmark (MTNeuro) is built on volumetric, micrometer-resolution X-ray microtomography images spanning a large thalamocortical section of mouse brain, encompassing multiple cortical and subcortical regions. We generated a number of different prediction challenges and evaluated several supervised and self-supervised models for brain-region prediction and pixel-level semantic segmentation of microstructures. Our experiments not only highlight the rich heterogeneity of this dataset, but also provide insights into how self-supervised approaches can be used to learn representations that capture multiple attributes of a single image and perform well on a variety of downstream tasks. Datasets, code, and pre-trained baseline models are provided at: https://mtneuro.github.io/ .
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The ability to convert reciprocating, i.e., alternating, actuation into rotary motion using linkages is hindered fundamentally by their poor torque transmission capability around kinematic singularity configurations. Here, we harness the elastic potential energy of a linear spring attached to the coupler link of four-bar mechanisms to manipulate force transmission around the kinematic singularities. We developed a theoretical model to explore the parameter space for proper force transmission in slider-crank and rocker-crank four-bar kinematics. Finally, we verified the proposed model and methodology by building and testing a macro-scale prototype of a slider-crank mechanism. We expect this approach to enable the development of small-scale rotary engines and robotic devices with closed kinematic chains dealing with serial kinematic singularities, such as linkages and parallel manipulators.
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This paper considers a combination of actuation tendons and measurement strings to achieve accurate shape sensing and direct kinematics of continuum robots. Assuming general string routing, a methodical Lie group formulation for the shape sensing of these robots is presented. The shape kinematics is expressed using arc-length-dependent curvature distributions parameterized by modal functions, and the Magnus expansion for Lie group integration is used to express the shape as a product of exponentials. The tendon and string length kinematic constraints are solved for the modal coefficients and the configuration space and body Jacobian are derived. The noise amplification index for the shape reconstruction problem is defined and used for optimizing the string/tendon routing paths, and a planar simulation study shows the minimal number of strings/tendons needed for accurate shape reconstruction. A torsionally stiff continuum segment is used for experimental evaluation, demonstrating mean (maximal) end-effector absolute position error of less than 2% (5%) of total length. Finally, a simulation study of a torsionally compliant segment demonstrates the approach for general deflections and string routings. We believe that the methods of this paper can benefit the design process, sensing and control of continuum and soft robots.
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Image classification with small datasets has been an active research area in the recent past. However, as research in this scope is still in its infancy, two key ingredients are missing for ensuring reliable and truthful progress: a systematic and extensive overview of the state of the art, and a common benchmark to allow for objective comparisons between published methods. This article addresses both issues. First, we systematically organize and connect past studies to consolidate a community that is currently fragmented and scattered. Second, we propose a common benchmark that allows for an objective comparison of approaches. It consists of five datasets spanning various domains (e.g., natural images, medical imagery, satellite data) and data types (RGB, grayscale, multispectral). We use this benchmark to re-evaluate the standard cross-entropy baseline and ten existing methods published between 2017 and 2021 at renowned venues. Surprisingly, we find that thorough hyper-parameter tuning on held-out validation data results in a highly competitive baseline and highlights a stunted growth of performance over the years. Indeed, only a single specialized method dating back to 2019 clearly wins our benchmark and outperforms the baseline classifier.
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The availability of frequent and cost-free satellite images is in growing demand in the research world. Such satellite constellations as Landsat 8 and Sentinel-2 provide a massive amount of valuable data daily. However, the discrepancy in the sensors' characteristics of these satellites makes it senseless to use a segmentation model trained on either dataset and applied to another, which is why domain adaptation techniques have recently become an active research area in remote sensing. In this paper, an experiment of domain adaptation through style-transferring is conducted using the HRSemI2I model to narrow the sensor discrepancy between Landsat 8 and Sentinel-2. This paper's main contribution is analyzing the expediency of that approach by comparing the results of segmentation using domain-adapted images with those without adaptation. The HRSemI2I model, adjusted to work with 6-band imagery, shows significant intersection-over-union performance improvement for both mean and per class metrics. A second contribution is providing different schemes of generalization between two label schemes - NALCMS 2015 and CORINE. The first scheme is standardization through higher-level land cover classes, and the second is through harmonization validation in the field.
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In this paper, we address the problem of multimodal emotion recognition from multiple physiological signals. We demonstrate that a Transformer-based approach is suitable for this task. In addition, we present how such models may be pretrained in a multimodal scenario to improve emotion recognition performances. We evaluate the benefits of using multimodal inputs and pre-training with our approach on a state-ofthe-art dataset.
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