在本文中，我们对数值模拟的加速感兴趣。我们专注于高超音速行星再入问题，该问题涉及耦合流体动力学和化学反应。模拟化学反应需要大部分计算时间，但另一方面，无法避免获得准确的预测。我们面临成本效率和准确性之间的权衡：模拟代码必须足够有效地在操作环境中使用，但必须足够准确，以忠实地预测现象。为了解决这个权衡，我们设计了一个混合模拟代码，将传统的流体动态求解器与近似化学反应的神经网络耦合。当在大数据上下文中应用以及它们源于其矩阵矢量结构的效率时，我们依靠它们的力量来实现重要的加速因子（$ \ tims 10 $至$ \ times 18.6 $）。本文旨在解释我们如何在实践中设计这种具有成本效益的混合模拟代码。最重要的是，我们描述了确保准确性保证的方法论，使我们能够超越传统的替代建模，并将这些代码用作参考。

通过神经网络解决新的机器学习问题总是意味着优化众多的超参数，以定义其结构并强烈影响其性能。在这项工作中，我们研究了基于希尔伯特·史克米特独立标准（HSIC）的面向目标灵敏度分析的使用，用于超参数分析和优化。超参数生活在通常复杂而尴尬的空间中。它们可以具有不同的本质（分类，离散，布尔，连续），相互作用并具有相互依存关系。所有这些使得执行经典灵敏度分析是不平凡的。我们可以减轻这些困难，以获取能够量化超参数对神经网络的最终错误的相对影响的强大分析指数。这种有价值的工具使我们能够更好地理解超参数，并使超参数优化更容易解释。我们在超参数优化的背景下说明了这些知识的好处，并得出了一种基于HSIC的优化算法，我们将其应用于MNIST和CIFAR，经典的机器学习数据集，但也适用于Runge功能和Bateman方程解决方案，兴趣解决方案的近似值，用于科学的机器学习。该方法产生既有竞争力又具有成本效益的神经网络。

本文提出了一种基于Hilbert-Schmidt独立标准（HSIC）的新有效的黑盒归因方法，这是一种基于再现核Hilbert Spaces（RKHS）的依赖度量。 HSIC测量了基于分布的内核的输入图像区域之间的依赖性和模型的输出。因此，它提供了由RKHS表示功能丰富的解释。可以非常有效地估计HSIC，与其他黑盒归因方法相比，大大降低了计算成本。我们的实验表明，HSIC的速度比以前的最佳黑盒归因方法快8倍，同时忠实。确实，我们改进或匹配了黑盒和白框归因方法的最新方法，用于具有各种最近的模型体系结构的Imagenet上的几个保真度指标。重要的是，我们表明这些进步可以被转化为有效而忠实地解释诸如Yolov4之类的对象检测模型。最后，我们通过提出一种新的内核来扩展传统的归因方法，从而实现基于HSIC的重要性分数的正交分解，从而使我们不仅可以评估每个图像贴片的重要性，还可以评估其成对相互作用的重要性。

在神经网络对功能的监督学习的背景下，我们声称并经验证明，当数据集的分布集中在学习功能陡峭的区域时，神经网络会产生更好的结果。我们首先使用泰勒（Taylor）扩展以数学上可行的方式来欺骗这一假设，并根据要学习的功能的导数强调新的培训分布。然后，理论推导允许构建一种我们称为基于方差的样本加权（VBSW）的方法。VBSW使用标签局部差异来加权训练点。该方法是一般，可扩展的，具有成本效益的，并且可以显着提高大量神经网络的性能，以在图像，文本和多元数据上进行各种分类和回归任务。我们通过涉及从线性模型到重新NET和BERT的神经网络的实验来强调其优势。

The success of neural networks builds to a large extent on their ability to create internal knowledge representations from real-world high-dimensional data, such as images, sound, or text. Approaches to extract and present these representations, in order to explain the neural network's decisions, is an active and multifaceted research field. To gain a deeper understanding of a central aspect of this field, we have performed a targeted review focusing on research that aims to associate internal representations with human understandable concepts. In doing this, we added a perspective on the existing research by using primarily deductive nomological explanations as a proposed taxonomy. We find this taxonomy and theories of causality, useful for understanding what can be expected, and not expected, from neural network explanations. The analysis additionally uncovers an ambiguity in the reviewed literature related to the goal of model explainability; is it understanding the ML model or, is it actionable explanations useful in the deployment domain?

Many problems in machine learning involve bilevel optimization (BLO), including hyperparameter optimization, meta-learning, and dataset distillation. Bilevel problems consist of two nested sub-problems, called the outer and inner problems, respectively. In practice, often at least one of these sub-problems is overparameterized. In this case, there are many ways to choose among optima that achieve equivalent objective values. Inspired by recent studies of the implicit bias induced by optimization algorithms in single-level optimization, we investigate the implicit bias of gradient-based algorithms for bilevel optimization. We delineate two standard BLO methods -- cold-start and warm-start -- and show that the converged solution or long-run behavior depends to a large degree on these and other algorithmic choices, such as the hypergradient approximation. We also show that the inner solutions obtained by warm-start BLO can encode a surprising amount of information about the outer objective, even when the outer parameters are low-dimensional. We believe that implicit bias deserves as central a role in the study of bilevel optimization as it has attained in the study of single-level neural net optimization.

An expansion of aberrant brain cells is referred to as a brain tumor. The brain's architecture is extremely intricate, with several regions controlling various nervous system processes. Any portion of the brain or skull can develop a brain tumor, including the brain's protective coating, the base of the skull, the brainstem, the sinuses, the nasal cavity, and many other places. Over the past ten years, numerous developments in the field of computer-aided brain tumor diagnosis have been made. Recently, instance segmentation has attracted a lot of interest in numerous computer vision applications. It seeks to assign various IDs to various scene objects, even if they are members of the same class. Typically, a two-stage pipeline is used to perform instance segmentation. This study shows brain cancer segmentation using YOLOv5. Yolo takes dataset as picture format and corresponding text file. You Only Look Once (YOLO) is a viral and widely used algorithm. YOLO is famous for its object recognition properties. You Only Look Once (YOLO) is a popular algorithm that has gone viral. YOLO is well known for its ability to identify objects. YOLO V2, V3, V4, and V5 are some of the YOLO latest versions that experts have published in recent years. Early brain tumor detection is one of the most important jobs that neurologists and radiologists have. However, it can be difficult and error-prone to manually identify and segment brain tumors from Magnetic Resonance Imaging (MRI) data. For making an early diagnosis of the condition, an automated brain tumor detection system is necessary. The model of the research paper has three classes. They are respectively Meningioma, Pituitary, Glioma. The results show that, our model achieves competitive accuracy, in terms of runtime usage of M2 10 core GPU.

Large language models (LLMs) have demonstrated impressive capabilities in natural language understanding and generation, but the quality bar for medical and clinical applications is high. Today, attempts to assess models' clinical knowledge typically rely on automated evaluations on limited benchmarks. There is no standard to evaluate model predictions and reasoning across a breadth of tasks. To address this, we present MultiMedQA, a benchmark combining six existing open question answering datasets spanning professional medical exams, research, and consumer queries; and HealthSearchQA, a new free-response dataset of medical questions searched online. We propose a framework for human evaluation of model answers along multiple axes including factuality, precision, possible harm, and bias. In addition, we evaluate PaLM (a 540-billion parameter LLM) and its instruction-tuned variant, Flan-PaLM, on MultiMedQA. Using a combination of prompting strategies, Flan-PaLM achieves state-of-the-art accuracy on every MultiMedQA multiple-choice dataset (MedQA, MedMCQA, PubMedQA, MMLU clinical topics), including 67.6% accuracy on MedQA (US Medical License Exam questions), surpassing prior state-of-the-art by over 17%. However, human evaluation reveals key gaps in Flan-PaLM responses. To resolve this we introduce instruction prompt tuning, a parameter-efficient approach for aligning LLMs to new domains using a few exemplars. The resulting model, Med-PaLM, performs encouragingly, but remains inferior to clinicians. We show that comprehension, recall of knowledge, and medical reasoning improve with model scale and instruction prompt tuning, suggesting the potential utility of LLMs in medicine. Our human evaluations reveal important limitations of today's models, reinforcing the importance of both evaluation frameworks and method development in creating safe, helpful LLM models for clinical applications.

Migraine is a high-prevalence and disabling neurological disorder. However, information migraine management in real-world settings could be limited to traditional health information sources. In this paper, we (i) verify that there is substantial migraine-related chatter available on social media (Twitter and Reddit), self-reported by migraine sufferers; (ii) develop a platform-independent text classification system for automatically detecting self-reported migraine-related posts, and (iii) conduct analyses of the self-reported posts to assess the utility of social media for studying this problem. We manually annotated 5750 Twitter posts and 302 Reddit posts. Our system achieved an F1 score of 0.90 on Twitter and 0.93 on Reddit. Analysis of information posted by our 'migraine cohort' revealed the presence of a plethora of relevant information about migraine therapies and patient sentiments associated with them. Our study forms the foundation for conducting an in-depth analysis of migraine-related information using social media data.

Human linguistic capacity is often characterized by compositionality and the generalization it enables -- human learners can produce and comprehend novel complex expressions by composing known parts. Several benchmarks exploit distributional control across training and test to gauge compositional generalization, where certain lexical items only occur in limited contexts during training. While recent work using these benchmarks suggests that pretrained models achieve impressive generalization performance, we argue that exposure to pretraining data may break the aforementioned distributional control. Using the COGS benchmark of Kim and Linzen (2020), we test two modified evaluation setups that control for this issue: (1) substituting context-controlled lexical items with novel character sequences, and (2) substituting them with special tokens represented by novel embeddings. We find that both of these setups lead to lower generalization performance in T5 (Raffel et al., 2020), suggesting that previously reported results have been overestimated due to uncontrolled lexical exposure during pretraining. The performance degradation is more extreme with novel embeddings, and the degradation increases with the amount of pretraining data, highlighting an interesting case of inverse scaling.