图像分段是许多图像处理和计算机视觉任务中的重要组成部分。图像分割的主要目标是简化图像以进行更容易的分析，并且有两种广泛的方法来实现这一点：基于边缘的方法，提取特定已知对象的边界，以及基于区域的方法，将图像分区为区域是统计上同质的。一种更突出的边缘查找方法，称为级别设置方法，在具有梯度下降之前在图像平面中演化的零电平轮廓，直到轮廓融合到对象边界。虽然经典水平集合方法及其变体已经证明在分割真实图像中成功，但是在没有先验的图像的情况下，它们易于变得卡在图像平面的噪声区域中，并且它们不能提供超出物体外边界位置的细节。我们提出了对变分级别设置图像分割方法的修改，该方法可以通过利用随机点初始化来快速检测对象边界。我们通过比较我们对真实图像对突出肉体方法的方法来展示我们方法的功效。

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.

Previous work has shown the potential of deep learning to predict renal obstruction using kidney ultrasound images. However, these image-based classifiers have been trained with the goal of single-visit inference in mind. We compare methods from video action recognition (i.e. convolutional pooling, LSTM, TSM) to adapt single-visit convolutional models to handle multiple visit inference. We demonstrate that incorporating images from a patient's past hospital visits provides only a small benefit for the prediction of obstructive hydronephrosis. Therefore, inclusion of prior ultrasounds is beneficial, but prediction based on the latest ultrasound is sufficient for patient risk stratification.

Artificial intelligence methods including deep neural networks (DNN) can provide rapid molecular classification of tumors from routine histology with accuracy that matches or exceeds human pathologists. Discerning how neural networks make their predictions remains a significant challenge, but explainability tools help provide insights into what models have learned when corresponding histologic features are poorly defined. Here, we present a method for improving explainability of DNN models using synthetic histology generated by a conditional generative adversarial network (cGAN). We show that cGANs generate high-quality synthetic histology images that can be leveraged for explaining DNN models trained to classify molecularly-subtyped tumors, exposing histologic features associated with molecular state. Fine-tuning synthetic histology through class and layer blending illustrates nuanced morphologic differences between tumor subtypes. Finally, we demonstrate the use of synthetic histology for augmenting pathologist-in-training education, showing that these intuitive visualizations can reinforce and improve understanding of histologic manifestations of tumor biology.

We consider the problem of data classification where the training set consists of just a few data points. We explore this phenomenon mathematically and reveal key relationships between the geometry of an AI model's feature space, the structure of the underlying data distributions, and the model's generalisation capabilities. The main thrust of our analysis is to reveal the influence on the model's generalisation capabilities of nonlinear feature transformations mapping the original data into high, and possibly infinite, dimensional spaces.

Partially observable Markov decision processes (POMDPs) provide a flexible representation for real-world decision and control problems. However, POMDPs are notoriously difficult to solve, especially when the state and observation spaces are continuous or hybrid, which is often the case for physical systems. While recent online sampling-based POMDP algorithms that plan with observation likelihood weighting have shown practical effectiveness, a general theory characterizing the approximation error of the particle filtering techniques that these algorithms use has not previously been proposed. Our main contribution is bounding the error between any POMDP and its corresponding finite sample particle belief MDP (PB-MDP) approximation. This fundamental bridge between PB-MDPs and POMDPs allows us to adapt any sampling-based MDP algorithm to a POMDP by solving the corresponding particle belief MDP, thereby extending the convergence guarantees of the MDP algorithm to the POMDP. Practically, this is implemented by using the particle filter belief transition model as the generative model for the MDP solver. While this requires access to the observation density model from the POMDP, it only increases the transition sampling complexity of the MDP solver by a factor of $\mathcal{O}(C)$, where $C$ is the number of particles. Thus, when combined with sparse sampling MDP algorithms, this approach can yield algorithms for POMDPs that have no direct theoretical dependence on the size of the state and observation spaces. In addition to our theoretical contribution, we perform five numerical experiments on benchmark POMDPs to demonstrate that a simple MDP algorithm adapted using PB-MDP approximation, Sparse-PFT, achieves performance competitive with other leading continuous observation POMDP solvers.

通用数据模型解决了标准化电子健康记录（EHR）数据的许多挑战，但无法将其集成深度表型所需的资源。开放的生物学和生物医学本体论（OBO）铸造本体论提供了可用于生物学知识的语义计算表示，并能够整合多种生物医学数据。但是，将EHR数据映射到OBO Foundry本体论需要大量的手动策展和域专业知识。我们介绍了一个框架，用于将观察性医学成果合作伙伴关系（OMOP）标准词汇介绍给OBO铸造本体。使用此框架，我们制作了92,367条条件，8,615种药物成分和10,673个测量结果的映射。域专家验证了映射准确性，并且在24家医院进行检查时，映射覆盖了99％的条件和药物成分和68％的测量结果。最后，我们证明OMOP2OBO映射可以帮助系统地识别可能受益于基因检测的未诊断罕见病患者。

成像表明临床前和人类肿瘤是异质性的，即单个肿瘤可以表现出多个区域，在正常发育过程中均表现出不同的行为，也可以反应治疗。在对照组肿瘤中观察到的大变化可能会掩盖由于归因于变化原因的歧义而导致的显着治疗作用的检测。由于实验设计的局限性，而不是由于治疗衰竭，这可能会阻碍有效疗法的发展。描述了对成像信号中生物变异和异质性进行建模的改进方法。具体而言，线性泊松建模（LPM）在放疗前和72小时之前评估了两种结直肠癌的异种移植模型，在放疗前和72小时后评估了明显的扩散效率（ADC）的变化。使用基本ADC分布参数的常规t检验分析将测量变化的统计显着性与可实现的变化的统计显着性进行了比较。当LPM应用于治疗的肿瘤时，LPM检测到了高度显着的变化。与常规方法相比，所有肿瘤的分析对于所有肿瘤都很重要，相当于4倍的增益（即等同于样本量大16倍）。相比之下，只有使用t检验在队列水平上检测到极大的变化，从而限制了其在个性化医学中的潜在用途，并增加了测试过程中所需的动物数量。此外，LPM使每个异种移植模型估计响应和非反应组织的相对体积。对处理过的异种移植物的剩余分析提供了质量控制并确定了潜在的异常值，从而提高了对临床相关样本量的LPM数据的信心。

ICECUBE是一种用于检测1 GEV和1 PEV之间大气和天体中微子的光学传感器的立方公斤阵列，该阵列已部署1.45 km至2.45 km的南极的冰盖表面以下1.45 km至2.45 km。来自ICE探测器的事件的分类和重建在ICeCube数据分析中起着核心作用。重建和分类事件是一个挑战，这是由于探测器的几何形状，不均匀的散射和冰中光的吸收，并且低于100 GEV的光，每个事件产生的信号光子数量相对较少。为了应对这一挑战，可以将ICECUBE事件表示为点云图形，并将图形神经网络（GNN）作为分类和重建方法。 GNN能够将中微子事件与宇宙射线背景区分开，对不同的中微子事件类型进行分类，并重建沉积的能量，方向和相互作用顶点。基于仿真，我们提供了1-100 GEV能量范围的比较与当前ICECUBE分析中使用的当前最新最大似然技术，包括已知系统不确定性的影响。对于中微子事件分类，与当前的IceCube方法相比，GNN以固定的假阳性速率（FPR）提高了信号效率的18％。另外，GNN在固定信号效率下将FPR的降低超过8（低于半百分比）。对于能源，方向和相互作用顶点的重建，与当前最大似然技术相比，分辨率平均提高了13％-20％。当在GPU上运行时，GNN能够以几乎是2.7 kHz的中位数ICECUBE触发速率的速率处理ICECUBE事件，这打开了在在线搜索瞬态事件中使用低能量中微子的可能性。

光环伴形培养基中的离子气体通过热阳光阳光层（TSZ）效应在宇宙微波背景上留下烙印。来自活性银河核（AGN）和超新星的反馈会影响晕孔集成TSZ通量的测量（$ y_ \ mathrm {sz} $），并导致其与光晕质量的关系（$ y_ \ mathrm {sz} -mm $ ）偏离病毒定理的自相似幂律预测。我们对使用骆驼，一套流体动力模拟的套件进行了全面研究，反馈处方的差异很大。我们使用两个机器学习工具（随机森林和符号回归）的组合来搜索$ y-m $关系的类似物，这对低质量的反馈过程（$ m \ sillesim 10^{14} \，h^， {-1} \，m_ \ odot $）;我们发现，仅替换$ y \ rightarrow y（1+m _*/m_ \ mathrm {gas}）$在关系中使其非常相似。这可以用作低质量簇和星系组的强大多波长质量代理。我们的方法通常对于提高其他天体分级关系的有效性领域通常也很有用。我们还预测，$ y-m $关系的测量值可以在反馈参数的某些组合和/或排除超级新闻和AGN反馈模型的主要部分，以提供百分比的约束。艺术流体动力模拟。我们的结果对于使用即将进行的SZ调查（例如SO，CMB-S4）和Galaxy Surveys（例如Desi和Rubin）来限制Baryonic反馈的性质。最后，我们发现，$ y-m _*$的另一种关系提供了有关反馈的补充信息，而不是$ y-m $。