在硅组织模型中，可以评估磁共振成像的定量模型。这包括对成像生物标志物和组织微结构参数的验证和灵敏度分析。我们提出了一种新的方法来生成心肌微结构的现实数值幻影。我们扩展了以前的研究，该研究考虑了心肌细胞的变异性，心肌细胞（插入式椎间盘）之间的水交换，心肌微结构混乱和四个钣金方向。在该方法的第一阶段，心肌细胞和钣金是通过考虑心肌到骨膜细胞连接的形状变异性和插入式椎间盘而产生的。然后，将薄板汇总和定向在感兴趣的方向上。我们的形态计量学研究表明，数值和真实（文献）心肌细胞数据的体积，长度以及一级和次要轴的分布之间没有显着差异（$ p> 0.01 $）。结构相关性分析证实了硅内组织与实际组织的混乱类别相同。此外，心肌细胞的模拟螺旋角（HA）和输入HA（参考值）之间的绝对角度差（$ 4.3^\ Circ \ PM 3.1^\ Circ $）与所测量HA之间的绝对角差有很好的一致性使用实验性心脏扩散张量成像（CDTI）和组织学（参考值）（Holmes等，2000）（$ 3.7^\ Circ \ PM6.4^\ Circ $）和（Scollan等，1998）（$ 4.9） ^\ circ \ pm 14.6^\ circ $）。使用结构张量成像（黄金标准）和实验性CDTI，输入和模拟CDTI的特征向量和模拟CDTI的角度之间的角度距离小于测量角度之间的角度距离。这些结果证实，所提出的方法比以前的研究可以为心肌产生更丰富的数值幻象。

标准平面（SP）定位对于常规临床超声（US）诊断至关重要。与2D US相比，3D US可以一次扫描获得多个视图平面，并通过添加冠状平面提供完整的解剖结构。但是，由于方向的可变性和巨大的搜索空间，在3D US中手动导航SPS是费力的和有偏见的。在这项研究中，我们介绍了3D US中自动SP本地化的新型增强学习（RL）框架。我们的贡献是三倍。首先，我们将3D中的SP定位作为RL中的基于切线的问题，以重组动作空间并大大降低搜索空间。其次，我们设计了一种辅助任务学习策略，以增强模型识别跨越平面搜索中非SPS和SP的微妙差异的能力。最后，我们通过同时利用空间和解剖学信息来提出空间 - 动态奖励，以有效地指导学习轨迹。我们探讨了我们方法在子宫和胎儿脑数据集上定位四个SP的功效。实验表明，我们的方法达到了较高的定位精度以及稳健的性能。

复发性喉神经（RLN）的肿瘤浸润是机器人甲状腺切除术的禁忌症，很难通过标准喉镜检测。超声（US）是RLN检测的可行替代方法，因为其安全性和提供实时反馈的能力。但是，直径通常小于3mm的RLN的微小性对RLN的准确定位构成了重大挑战。在这项工作中，我们为RLN本地化提出了一个知识驱动的框架，模仿了外科医生根据其周围器官识别RLN的标准方法。我们基于器官之间固有的相对空间关系构建了先前的解剖模型。通过贝叶斯形状比对（BSA），我们获得了围绕RLN的感兴趣区域（ROI）中心的候选坐标。 ROI允许使用基于多尺度语义信息的双路径识别网络确定RLN的精制质心的视野减少。实验结果表明，与最先进的方法相比，所提出的方法达到了较高的命中率和距离较小的距离误差。

In this work, we propose a novel generative model for mapping inputs to structured, high-dimensional outputs using structured conditional normalizing flows and Gaussian process regression. The model is motivated by the need to characterize uncertainty in the input/output relationship when making inferences on new data. In particular, in the physical sciences, limited training data may not adequately characterize future observed data; it is critical that models adequately indicate uncertainty, particularly when they may be asked to extrapolate. In our proposed model, structured conditional normalizing flows provide parsimonious latent representations that relate to the inputs through a Gaussian process, providing exact likelihood calculations and uncertainty that naturally increases away from the training data inputs. We demonstrate the methodology on laser-induced breakdown spectroscopy data from the ChemCam instrument onboard the Mars rover Curiosity. ChemCam was designed to recover the chemical composition of rock and soil samples by measuring the spectral properties of plasma atomic emissions induced by a laser pulse. We show that our model can generate realistic spectra conditional on a given chemical composition and that we can use the model to perform uncertainty quantification of chemical compositions for new observed spectra. Based on our results, we anticipate that our proposed modeling approach may be useful in other scientific domains with high-dimensional, complex structure where it is important to quantify predictive uncertainty.

Selective classification involves identifying the subset of test samples that a model can classify with high accuracy, and is important for applications such as automated medical diagnosis. We argue that this capability of identifying uncertain samples is valuable for training classifiers as well, with the aim of building more accurate classifiers. We unify these dual roles by training a single auxiliary meta-network to output an importance weight as a function of the instance. This measure is used at train time to reweight training data, and at test-time to rank test instances for selective classification. A second, key component of our proposal is the meta-objective of minimizing dropout variance (the variance of classifier output when subjected to random weight dropout) for training the metanetwork. We train the classifier together with its metanetwork using a nested objective of minimizing classifier loss on training data and meta-loss on a separate meta-training dataset. We outperform current state-of-the-art on selective classification by substantial margins--for instance, upto 1.9% AUC and 2% accuracy on a real-world diabetic retinopathy dataset. Finally, our meta-learning framework extends naturally to unsupervised domain adaptation, given our unsupervised variance minimization meta-objective. We show cumulative absolute gains of 3.4% / 3.3% accuracy and AUC over the other baselines in domain shift settings on the Retinopathy dataset using unsupervised domain adaptation.

Many real-world learning scenarios face the challenge of slow concept drift, where data distributions change gradually over time. In this setting, we pose the problem of learning temporally sensitive importance weights for training data, in order to optimize predictive accuracy. We propose a class of temporal reweighting functions that can capture multiple timescales of change in the data, as well as instance-specific characteristics. We formulate a bi-level optimization criterion, and an associated meta-learning algorithm, by which these weights can be learned. In particular, our formulation trains an auxiliary network to output weights as a function of training instances, thereby compactly representing the instance weights. We validate our temporal reweighting scheme on a large real-world dataset of 39M images spread over a 9 year period. Our extensive experiments demonstrate the necessity of instance-based temporal reweighting in the dataset, and achieve significant improvements to classical batch-learning approaches. Further, our proposal easily generalizes to a streaming setting and shows significant gains compared to recent continual learning methods.

Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License.

从数据中学习的定向无环图（DAG）的组合问题最近被构成了纯连续优化问题，它通过基于矩阵指数函数的痕迹利用DAG的可区分无环表征。现有的无环特征基于以下想法：邻接矩阵的功率包含有关步行和周期的信息。在这项工作中，我们提出了一个基于log-determinant（log-det）函数的$ \ textit {根本不同的} $ acyclicity表征，该功能利用了dags的nilpotency属性。为了处理DAG的固有不对称性，我们将日志数据表征的域与$ \ textit {m-matrices} $的集合联系起来，这是与锥体定义的经典日志函数的关键区别积极的矩阵。与先前提出的无环函数相似，我们的表征也是精确且可区分的。但是，与现有特征相比，我们的对数数据函数：（1）更好地检测大周期； （2）行为更好的梯度； （3）它的运行时间在实践中的数量级更快。从优化侧，我们删除了典型的增强拉格朗日方案，并提出了Dagma（$ \ textit {ocyclicity} $的M-矩阵{textIt {定向无环形图），这种方法类似于屏障方法的中心路径。 DAGMA的中心路径中的每个点都是通过我们的log-det函数正常的无约束问题的解决方案，然后我们证明在中心路径的极限下，保证解决方案是DAG。最后，我们为$ \ textit {linear} $和$ \ textit {nonlinear} $ sem提供了广泛的实验，并证明我们的方法可以达到针对最先进方法的大加速和较小的结构锤距。

基于概念的黑框模型的解释通常更为直观，让人类理解。基于概念的解释最广泛采用的方法是概念激活向量（CAV）。CAV依靠学习给定模型和概念的某些潜在表示之间的线性关系。线性可分离性通常是隐式假定的，但通常不正确。在这项工作中，我们从基于概念的解释和提出的概念梯度（CG）的最初意图开始，将基于概念的解释扩展到线性概念功能之外。我们表明，对于一般（潜在的非线性）概念，我们可以数学上评估如何影响模型预测的概念的小变化，从而导致基于梯度的解释扩展到概念空间。我们从经验上证明，在玩具示例和现实世界数据集中，CG表现优于CAV。

口服食物挑战（OFC）对于准确诊断患者的食物过敏至关重要。但是，患者不愿接受OFC，对于那些这样做的患者，在农村/社区医疗保健环境中，对过敏症患者的使用率有限。通过机器学习方法对OFC结果的预测可以促进在家中食品过敏原的删除，在OFC中改善患者和医师的舒适度，并通过最大程度地减少执行的OFC的数量来节省医疗资源。临床数据是从共同接受1,284个OFC的1,12例患者那里收集的，包括临床因素，包括血清特异性IgE，总IgE，皮肤刺测试（SPTS），症状，性别和年龄。使用这些临床特征，构建了机器学习模型，以预测花生，鸡蛋和牛奶挑战的结果。每种过敏原的最佳性能模型是使用凹入和凸内核（LUCCK）方法创建的，该方法在曲线（AUC）（AUC）下分别用于花生，鸡蛋和牛奶OFC预测为0.76、0.68和0.70， 。通过Shapley添加说明（SHAP）的模型解释表明，特定的IgE以及SPTS的Wheal和Flare值高度预测了OFC结果。该分析的结果表明，机器学习有可能预测OFC结果，并揭示了相关的临床因素进行进一步研究。