Multivariate Hawkes processes are temporal point processes extensively applied to model event data with dependence on past occurrences and interaction phenomena. In the generalised nonlinear model, positive and negative interactions between the components of the process are allowed, therefore accounting for so-called excitation and inhibition effects. In the nonparametric setting, learning the temporal dependence structure of Hawkes processes is often a computationally expensive task, all the more with Bayesian estimation methods. In general, the posterior distribution in the nonlinear Hawkes model is non-conjugate and doubly intractable. Moreover, existing Monte-Carlo Markov Chain methods are often slow and not scalable to high-dimensional processes in practice. Recently, efficient algorithms targeting a mean-field variational approximation of the posterior distribution have been proposed. In this work, we unify existing variational Bayes inference approaches under a general framework, that we theoretically analyse under easily verifiable conditions on the prior, the variational class, and the model. We notably apply our theory to a novel spike-and-slab variational class, that can induce sparsity through the connectivity graph parameter of the multivariate Hawkes model. Then, in the context of the popular sigmoid Hawkes model, we leverage existing data augmentation technique and design adaptive and sparsity-inducing mean-field variational methods. In particular, we propose a two-step algorithm based on a thresholding heuristic to select the graph parameter. Through an extensive set of numerical simulations, we demonstrate that our approach enjoys several benefits: it is computationally efficient, can reduce the dimensionality of the problem by selecting the graph parameter, and is able to adapt to the smoothness of the underlying parameter.

贝叶斯核心通过构建数据点的一个较小的加权子集近似后验分布。任何在整个后验上运行的推理过程在计算上昂贵，都可以在核心上廉价地运行，其结果近似于完整数据上的结果。但是，当前方法受到大量运行时的限制，或者需要用户指定向完整后部的低成本近似值。我们提出了一种贝叶斯核心结构算法，该算法首先选择均匀随机的数据子集，然后使用新型的准Newton方法优化权重。我们的算法是一种易于实现的黑框方法，不需要用户指定低成本后近似。它是第一个在输出核心后部的KL差异上带有一般高概率构成的。实验表明，我们的方法可与具有可比的施工时间的替代方案相比，核心质量有显着改善，所需的存储成本和用户输入要少得多。

Deep neural networks (DNNs) have rapidly become a \textit{de facto} choice for medical image understanding tasks. However, DNNs are notoriously fragile to the class imbalance in image classification. We further point out that such imbalance fragility can be amplified when it comes to more sophisticated tasks such as pathology localization, as imbalances in such problems can have highly complex and often implicit forms of presence. For example, different pathology can have different sizes or colors (w.r.t.the background), different underlying demographic distributions, and in general different difficulty levels to recognize, even in a meticulously curated balanced distribution of training data. In this paper, we propose to use pruning to automatically and adaptively identify \textit{hard-to-learn} (HTL) training samples, and improve pathology localization by attending them explicitly, during training in \textit{supervised, semi-supervised, and weakly-supervised} settings. Our main inspiration is drawn from the recent finding that deep classification models have difficult-to-memorize samples and those may be effectively exposed through network pruning \cite{hooker2019compressed} - and we extend such observation beyond classification for the first time. We also present an interesting demographic analysis which illustrates HTLs ability to capture complex demographic imbalances. Our extensive experiments on the Skin Lesion Localization task in multiple training settings by paying additional attention to HTLs show significant improvement of localization performance by $\sim$2-3\%.

AI-powered Medical Imaging has recently achieved enormous attention due to its ability to provide fast-paced healthcare diagnoses. However, it usually suffers from a lack of high-quality datasets due to high annotation cost, inter-observer variability, human annotator error, and errors in computer-generated labels. Deep learning models trained on noisy labelled datasets are sensitive to the noise type and lead to less generalization on the unseen samples. To address this challenge, we propose a Robust Stochastic Knowledge Distillation (RoS-KD) framework which mimics the notion of learning a topic from multiple sources to ensure deterrence in learning noisy information. More specifically, RoS-KD learns a smooth, well-informed, and robust student manifold by distilling knowledge from multiple teachers trained on overlapping subsets of training data. Our extensive experiments on popular medical imaging classification tasks (cardiopulmonary disease and lesion classification) using real-world datasets, show the performance benefit of RoS-KD, its ability to distill knowledge from many popular large networks (ResNet-50, DenseNet-121, MobileNet-V2) in a comparatively small network, and its robustness to adversarial attacks (PGD, FSGM). More specifically, RoS-KD achieves >2% and >4% improvement on F1-score for lesion classification and cardiopulmonary disease classification tasks, respectively, when the underlying student is ResNet-18 against recent competitive knowledge distillation baseline. Additionally, on cardiopulmonary disease classification task, RoS-KD outperforms most of the SOTA baselines by ~1% gain in AUC score.

标准化流量（NF）是基于可能性的强大生成模型，能够在表达性和拖延性之间进行折衷，以模拟复杂的密度。现已建立的研究途径利用了最佳运输（OT），并寻找Monge地图，即源和目标分布之间的努力最小的模型。本文介绍了一种基于Brenier的极性分解定理的方法，该方法将任何受过训练的NF转换为更高效率的版本而不改变最终密度。我们通过学习源（高斯）分布的重新排列来最大程度地减少源和最终密度之间的OT成本。由于Euler的方程式，我们进一步限制了导致估计的Monge图的路径，将估计的Monge地图放在量化量的差异方程的空间中。所提出的方法导致几种现有模型的OT成本降低的平滑流动，而不会影响模型性能。

传统上，音乐标记和基于内容的检索系统是使用预定的本体论构建的，涵盖了一组刚性的音乐属性或文本查询。本文介绍了Mulan：首次尝试新一代的声学模型，这些模型将音乐音频直接与无约束的自然语言描述联系起来。Mulan采用了两座联合音频文本嵌入模型的形式，该模型使用4400万张音乐录音（37万小时）和弱相关的自由形式文本注释训练。通过与广泛的音乐流派和文本样式（包括传统的音乐标签）的兼容性，由此产生的音频文本表示形式涵盖了现有的本体论，同时又毕业至真正的零击功能。我们通过一系列实验演示了Mulan嵌入的多功能性，包括转移学习，零照片标记，音乐域中的语言理解以及跨模式检索应用程序。

联合学习是一种数据解散隐私化技术，用于以安全的方式执行机器或深度学习。在本文中，我们介绍了有关联合学习的理论方面客户次数有所不同的用例。具体而言，使用从开放数据存储库中获得的胸部X射线图像提出了医学图像分析的用例。除了与隐私相关的优势外，还将研究预测的改进（就曲线下的准确性和面积而言）和减少执行时间（集中式方法）。将从培训数据中模拟不同的客户，以不平衡的方式选择，即，他们并非都有相同数量的数据。考虑三个或十个客户之间的结果与集中案件相比。间歇性客户将分析两种遵循方法，就像在实际情况下，某些客户可能会离开培训，一些新的新方法可能会进入培训。根据准确性，曲线下的区域和执行时间的结果，结果的结果的演变显示为原始数据被划分的客户次数。最后，提出了该领域的改进和未来工作。

在这项工作中，我们评估了人口模型和机器学习模型的合奏，以预测COVID-19大流行的不久的将来的演变，并在西班牙有特殊的用例。我们仅依靠开放和公共数据集，将发生率，疫苗接种，人类流动性和天气数据融合来喂养我们的机器学习模型（随机森林，梯度增强，K-Nearest邻居和内核岭回归）。我们使用发病率数据来调整经典人群模型（Gompertz，Logistic，Richards，Bertalanffy），以便能够更好地捕获数据的趋势。然后，我们整合了这两个模型家族，以获得更强大，更准确的预测。此外，我们已经观察到，当我们添加新功能（疫苗，移动性，气候条件）时，使用机器学习模型获得的预测有所改善，使用Shapley添加说明值分析了每个功能的重要性。就像在任何其他建模工作中一样，数据和预测质量都有多个局限性，因此必须从关键的角度看待它们，如我们在文本中所讨论的那样。我们的工作得出的结论是，这些模型的合奏使用可以改善单个预测（仅使用机器学习模型或仅使用人口模型），并且在由于缺乏相关数据而无法使用隔室模型的情况下，可以谨慎地应用。

患者调度是一项艰巨的任务，因为它涉及处理随机因素，例如患者未知的到达流动。调度癌症患者的放射治疗治疗面临着类似的问题。治疗患者需要在推荐的最后期限内开始治疗，即入院后14或28天，而在入院后1至3天内需要迫切治疗的姑息治疗的治疗能力。大多数癌症中心通过保留用于急诊患者的固定数量的治疗槽来解决问题。然而，这种平面预留方法并不理想，并且可能在某些日子里造成急诊患者的过期治疗，同时在其他几天内没有充分利用治疗能力，这也导致治疗患者的延迟治疗。这个问题在大型和拥挤的医院中特别严重。在本文中，我们提出了一种基于预测的在线动态放射治疗调度方法。一个离线问题，其中提前已知所有未来的患者到达，以使用整数编程来解决。然后培训回归模型以识别患者到达模式之间的链接及其理想的等待时间。然后，培训的回归模型以基于预测的方法嵌入，该方法根据其特征和日历的当前状态来调度患者。数值结果表明，我们的预测方法有效地防止了应急患者的过度处理，同时与基于平面预留政策的其他调度方法相比保持良好的等待时间。

本文介绍了一种机器学习方法，可以在宏观水平下模拟电动车辆的电力消耗，即在不存在速度轮廓，同时保持微观级别精度。对于这项工作，我们利用了基于代理的代理的运输工具来模拟了在各种场景变化的大芝加哥地区发生的模型旅行，以及基于物理的建模和仿真工具，以提供高保真能量消耗值。产生的结果构成了车辆路径能量结果的非常大的数据集，其捕获车辆和路由设置的可变性，并且掩盖了车速动力学的高保真时间序列。我们表明，尽管掩盖了影响能量消耗的所有内部动态，但是可以以深入的学习方法准确地学习聚合级能量消耗值。当有大规模数据可用，并且仔细量身定制的功能工程，精心设计的模型可以克服和检索潜在信息。该模型已部署并集成在Polaris运输系统仿真工具中，以支持各个充电决策的实时行为运输模型，以及电动车辆的重新排出。