肿瘤分割是放疗治疗计划的基本步骤。为了确定口咽癌患者(OPC)原发性肿瘤(GTVP)的准确分割,需要同时评估不同图像模态,并从不同方向探索每个图像体积。此外,分割的手动固定边界忽略了肿瘤描述中已知的空间不确定性。这项研究提出了一种新型的自动深度学习(DL)模型,以在注册的FDG PET/CT图像上进行逐片自适应GTVP分割的辐射肿瘤学家。我们包括138名在我们研究所接受过(化学)辐射治疗的OPC患者。我们的DL框架利用了间和板板的上下文。连续3片的串联FDG PET/CT图像和GTVP轮廓的序列用作输入。进行了3倍的交叉验证,进行了3​​次,对从113例患者的轴向(a),矢状(s)和冠状(c)平面提取的序列进行了训练。由于体积中的连续序列包含重叠的切片,因此每个切片产生了平均的三个结果预测。在A,S和C平面中,输出显示具有预测肿瘤的概率不同的区域。使用平均骰子得分系数(DSC)评估了25名患者的模型性能。预测是最接近地面真理的概率阈值(在A中为0.70,s为0.70,在s中为0.77,在C平面中为0.80)。提出的DL模型的有希望的结果表明,注册的FDG PET/CT图像上的概率图可以指导逐片自适应GTVP分割中的辐射肿瘤学家。
translated by 谷歌翻译
In this book chapter, we briefly describe the main components that constitute the gradient descent method and its accelerated and stochastic variants. We aim at explaining these components from a mathematical point of view, including theoretical and practical aspects, but at an elementary level. We will focus on basic variants of the gradient descent method and then extend our view to recent variants, especially variance-reduced stochastic gradient schemes (SGD). Our approach relies on revealing the structures presented inside the problem and the assumptions imposed on the objective function. Our convergence analysis unifies several known results and relies on a general, but elementary recursive expression. We have illustrated this analysis on several common schemes.
translated by 谷歌翻译
Classical differential private DP-SGD implements individual clipping with random subsampling, which forces a mini-batch SGD approach. We provide a general differential private algorithmic framework that goes beyond DP-SGD and allows any possible first order optimizers (e.g., classical SGD and momentum based SGD approaches) in combination with batch clipping, which clips an aggregate of computed gradients rather than summing clipped gradients (as is done in individual clipping). The framework also admits sampling techniques beyond random subsampling such as shuffling. Our DP analysis follows the $f$-DP approach and introduces a new proof technique which allows us to also analyse group privacy. In particular, for $E$ epochs work and groups of size $g$, we show a $\sqrt{g E}$ DP dependency for batch clipping with shuffling. This is much better than the previously anticipated linear dependency in $g$ and is much better than the previously expected square root dependency on the total number of rounds within $E$ epochs which is generally much more than $\sqrt{E}$.
translated by 谷歌翻译
最近,大型高质量的公共数据集导致了卷积神经网络的发展,这些神经网络可以在专家病理学家水平上检测乳腺癌的淋巴结转移。许多癌症,无论起源地点如何,都可以转移到淋巴结。但是,收集和注释每种癌症类型的高量,高质量数据集都是具有挑战性的。在本文中,我们研究了如何在多任务设置中最有效地利用现有的高质量数据集,以实现紧密相关的任务。具体而言,我们将探索不同的训练和领域适应策略,包括预防灾难性遗忘,用于结肠和头颈癌症转移淋巴结中的灾难性遗忘。我们的结果表明,两项癌症转移检测任务的最新性能。此外,我们显示了从一种癌症类型到另一种癌症的反复适应以获得多任务转移检测网络的有效性。最后,我们表明,利用现有的高质量数据集可以显着提高新目标任务的性能,并且可以使用正则化有效地减轻灾难性遗忘。
translated by 谷歌翻译
通过离散采样观测来建模连续的动力系统是数据科学中的一个基本问题。通常,这种动力学是非本地过程随时间不可或缺的结果。因此,这些系统是用插差分化方程(IDE)建模的;构成积分和差分组件的微分方程的概括。例如,大脑动力学不是通过微分方程来准确模拟的,因为它们的行为是非马克维亚的,即动态是部分由历史决定的。在这里,我们介绍了神经IDE(NIDE),该框架使用神经网络建模IDE的普通和组成部分。我们在几个玩具和大脑活动数据集上测试NIDE,并证明NIDE的表现优于其他模型,包括神经ODE。这些任务包括时间外推,以及从看不见的初始条件中预测动态,我们在自由行为的小鼠中测试了全皮质活动记录。此外,我们表明,NIDE可以通过学识渊博的整体操作员将动力学分解为马尔可夫和非马克维亚成分,我们在氯胺酮的fMRI脑活动记录中测试了动力学。最后,整体操作员的整体提供了一个潜在空间,可深入了解潜在的动态,我们在宽阔的大脑成像记录上证明了这一点。总体而言,NIDE是一种新颖的方法,可以通过神经网络对复杂的非本地动力学进行建模。
translated by 谷歌翻译
我们解决了与行业相关的尺度上的机器人轨迹计划问题。我们的端到端解决方案将高度通用的随机键算法与模型堆叠和集成技术集成在一起,以及用于溶液细化的路径重新链接。核心优化模块由偏置的随机基遗传算法组成。通过与问题依赖性和问题相关模块的独特分离,我们通过约束的天然编码实现了有效的问题表示。我们表明,对替代算法范式(例如模拟退火)的概括是直接的。我们为行业规模的数据集提供数值基准结果。发现我们的方法始终超过贪婪的基线结果。为了评估当今量子硬件的功能,我们使用Amazon Braket上的QBSOLV在量子退火硬件上获得的经典方法进行了补充。最后,我们展示了如何将后者集成到我们的较大管道中,从而为问题提供了量子准备的混合解决方案。
translated by 谷歌翻译
Modeling lies at the core of both the financial and the insurance industry for a wide variety of tasks. The rise and development of machine learning and deep learning models have created many opportunities to improve our modeling toolbox. Breakthroughs in these fields often come with the requirement of large amounts of data. Such large datasets are often not publicly available in finance and insurance, mainly due to privacy and ethics concerns. This lack of data is currently one of the main hurdles in developing better models. One possible option to alleviating this issue is generative modeling. Generative models are capable of simulating fake but realistic-looking data, also referred to as synthetic data, that can be shared more freely. Generative Adversarial Networks (GANs) is such a model that increases our capacity to fit very high-dimensional distributions of data. While research on GANs is an active topic in fields like computer vision, they have found limited adoption within the human sciences, like economics and insurance. Reason for this is that in these fields, most questions are inherently about identification of causal effects, while to this day neural networks, which are at the center of the GAN framework, focus mostly on high-dimensional correlations. In this paper we study the causal preservation capabilities of GANs and whether the produced synthetic data can reliably be used to answer causal questions. This is done by performing causal analyses on the synthetic data, produced by a GAN, with increasingly more lenient assumptions. We consider the cross-sectional case, the time series case and the case with a complete structural model. It is shown that in the simple cross-sectional scenario where correlation equals causation the GAN preserves causality, but that challenges arise for more advanced analyses.
translated by 谷歌翻译
We present the interpretable meta neural ordinary differential equation (iMODE) method to rapidly learn generalizable (i.e., not parameter-specific) dynamics from trajectories of multiple dynamical systems that vary in their physical parameters. The iMODE method learns meta-knowledge, the functional variations of the force field of dynamical system instances without knowing the physical parameters, by adopting a bi-level optimization framework: an outer level capturing the common force field form among studied dynamical system instances and an inner level adapting to individual system instances. A priori physical knowledge can be conveniently embedded in the neural network architecture as inductive bias, such as conservative force field and Euclidean symmetry. With the learned meta-knowledge, iMODE can model an unseen system within seconds, and inversely reveal knowledge on the physical parameters of a system, or as a Neural Gauge to "measure" the physical parameters of an unseen system with observed trajectories. We test the validity of the iMODE method on bistable, double pendulum, Van der Pol, Slinky, and reaction-diffusion systems.
translated by 谷歌翻译
We propose Hierarchical ProtoPNet: an interpretable network that explains its reasoning process by considering the hierarchical relationship between classes. Different from previous methods that explain their reasoning process by dissecting the input image and finding the prototypical parts responsible for the classification, we propose to explain the reasoning process for video action classification by dissecting the input video frames on multiple levels of the class hierarchy. The explanations leverage the hierarchy to deal with uncertainty, akin to human reasoning: When we observe water and human activity, but no definitive action it can be recognized as the water sports parent class. Only after observing a person swimming can we definitively refine it to the swimming action. Experiments on ActivityNet and UCF-101 show performance improvements while providing multi-level explanations.
translated by 谷歌翻译
Artificial intelligence (AI) in the form of deep learning bears promise for drug discovery and chemical biology, $\textit{e.g.}$, to predict protein structure and molecular bioactivity, plan organic synthesis, and design molecules $\textit{de novo}$. While most of the deep learning efforts in drug discovery have focused on ligand-based approaches, structure-based drug discovery has the potential to tackle unsolved challenges, such as affinity prediction for unexplored protein targets, binding-mechanism elucidation, and the rationalization of related chemical kinetic properties. Advances in deep learning methodologies and the availability of accurate predictions for protein tertiary structure advocate for a $\textit{renaissance}$ in structure-based approaches for drug discovery guided by AI. This review summarizes the most prominent algorithmic concepts in structure-based deep learning for drug discovery, and forecasts opportunities, applications, and challenges ahead.
translated by 谷歌翻译