科学数据集通常具有层次结构:例如,在调查中,个人参与者(样本)可能会分为更高级别(单位),例如其地理区域。在这些设置中,兴趣通常是在探索单位级别而不是样本级别上的结构。可以根据其平均值之间的距离进行比较,但是这忽略了样本的单位内分布。在这里,我们使用Wasserstein距离度量标准开发了一种对层次数据集进行探索性分析的方法,该指标考虑了单位内分布的形状。我们使用T-SNE构建单元的2D嵌入,基于它们之间的成对瓦斯汀距离的矩阵。距离矩阵可以通过使用高斯分布近似于每个单元来有效计算,但是我们还提供了一种可扩展的方法来计算精确的Wasserstein距离。我们使用合成数据来证明我们的Wasserstein T-SNE的有效性,并将其应用于2017年德国议会选举的数据,将投票站视为样本和投票区。结果嵌入发现数据中有意义的结构。
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Objective: Imbalances of the electrolyte concentration levels in the body can lead to catastrophic consequences, but accurate and accessible measurements could improve patient outcomes. While blood tests provide accurate measurements, they are invasive and the laboratory analysis can be slow or inaccessible. In contrast, an electrocardiogram (ECG) is a widely adopted tool which is quick and simple to acquire. However, the problem of estimating continuous electrolyte concentrations directly from ECGs is not well-studied. We therefore investigate if regression methods can be used for accurate ECG-based prediction of electrolyte concentrations. Methods: We explore the use of deep neural networks (DNNs) for this task. We analyze the regression performance across four electrolytes, utilizing a novel dataset containing over 290000 ECGs. For improved understanding, we also study the full spectrum from continuous predictions to binary classification of extreme concentration levels. To enhance clinical usefulness, we finally extend to a probabilistic regression approach and evaluate different uncertainty estimates. Results: We find that the performance varies significantly between different electrolytes, which is clinically justified in the interplay of electrolytes and their manifestation in the ECG. We also compare the regression accuracy with that of traditional machine learning models, demonstrating superior performance of DNNs. Conclusion: Discretization can lead to good classification performance, but does not help solve the original problem of predicting continuous concentration levels. While probabilistic regression demonstrates potential practical usefulness, the uncertainty estimates are not particularly well-calibrated. Significance: Our study is a first step towards accurate and reliable ECG-based prediction of electrolyte concentration levels.
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Recently, attempts have been made to reduce annotation requirements in feature-based self-explanatory models for lung nodule diagnosis. As a representative, cRedAnno achieves competitive performance with considerably reduced annotation needs by introducing self-supervised contrastive learning to do unsupervised feature extraction. However, it exhibits unstable performance under scarce annotation conditions. To improve the accuracy and robustness of cRedAnno, we propose an annotation exploitation mechanism by conducting semi-supervised active learning with sparse seeding and training quenching in the learned semantically meaningful reasoning space to jointly utilise the extracted features, annotations, and unlabelled data. The proposed approach achieves comparable or even higher malignancy prediction accuracy with 10x fewer annotations, meanwhile showing better robustness and nodule attribute prediction accuracy under the condition of 1% annotations. Our complete code is open-source available: https://github.com/diku-dk/credanno.
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准确的几何表示对于开发有限元模型至关重要。尽管通常只有很少的数据在准确细分精美特征,例如缝隙和薄结构方面,虽然只有很少的数据就有良好的深度学习分割方法。随后,分段的几何形状需要劳动密集型手动修改,以达到可用于模拟目的的质量。我们提出了一种使用转移学习来重复使用分段差的数据集的策略,并结合了交互式学习步骤,其中数据对数据进行微调导致解剖上精确的分割适合模拟。我们使用改良的多平台UNET,该UNET使用下髋关节分段和专用损耗函数进行预训练,以学习间隙区域和后处理,以纠正由于旋转不变性而在对称类别上的微小不准确性。我们证明了这种可靠但概念上简单的方法,采用了临床验证的髋关节扫描扫描的临床验证结果。代码和结果3D模型可在以下网址提供:\ url {https://github.com/miccai2022-155/autoseg}
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基于特征的自我解释方法解释了他们的分类,从人类可行的特征方面。在医学成像社区中,这种临床知识的语义匹配大大增加了AI的可信度。但是,功能附加注释的成本仍然是一个紧迫的问题。我们通过提出Credanno来解决这个问题,这是一种用于肺结核诊断的数据/注释有效的自我解释方法。 Credanno通过引入自我保护的对比学习来大大减少注释需求,以减轻从注释中学习大多数参数的负担,从而通过两阶段的培训代替端到端的培训。当使用数百个结节样本和仅1%的注释训练时,Credanno在预测恶性肿瘤方面取得了竞争力的准确性,同时,在预测结节属性方面大多数以前的作品都显着超过了。学习空间的可视化进一步表明,恶性肿瘤和结节属性的聚类与临床知识一致。我们的完整代码可用:https://github.com/ludles/credanno。
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神经形态的神经网络处理器,以记忆中的计算横杆阵列的形式,或以亚阈值模拟和混合信号ASIC的形式,有望在基于NN的ML任务的计算密度和能源效率方面具有巨大优势。但是,由于过程变化和内在的设备物理学,这些技术容易出现计算非理想性。通过将参数噪声引入部署模型中,这会降低部署到处理器的网络的任务性能。虽然可以为每个处理器校准每个设备或单独训练网络,但这些方法对于商业部署而言是昂贵且不切实际的。因此,由于网络体系结构和参数的结果,需要替代方法来训练与参数变化固有强大的网络。我们提出了一种新的对抗网络优化算法,该算法在训练过程中攻击网络参数,并在参数变化时促进推断期间的稳健性能。我们的方法引入了正规化术语,惩罚网络对权重扰动的敏感性。我们将与先前产生参数不敏感的方法进行比较,例如辍学,体重平滑和训练过程中引入参数噪声。我们表明,我们的方法产生的模型对目标参数变化更强大,并且对随机参数变化同样强大。与其他方法相比,我们的方法在减肥景观的平坦位置中发现了最小值,这强调了我们技术发现的网络对参数扰动不太敏感。我们的工作提供了一种将神经网络体系结构部署到遭受计算非理想性的推理设备的方法,而性能的损失最少。 ...
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