彩票假说上的基础工作提出了令人兴奋的推论:在一个任务的背景下找到的获胜门票可以转移到类似的任务中,甚至可能在不同的架构中。这引起了广泛的兴趣,但是缺乏研究这种普遍性的方法。我们利用重新规范化群体理论是一种从理论物理学的有力工具来满足这一需求。我们发现,迭代幅度修剪是用于发现获胜门票的主要算法,是一种重新归一化组方案,可以看作是诱导参数空间中的流动。我们证明,带有可转让获胜门票的Resnet-50模型具有具有共同特性的流量,正如该理论所期望的那样。对BERT模型进行了类似的观察结果,并有证据表明其流量接近固定点。此外,我们利用我们的框架来研究跨重新结构架构转移的获胜门票,观察到较小的模型具有比较大模型更均匀的属性的流动,从而使它们之间的转移变得复杂。
translated by 谷歌翻译
神经网络微分方程(NN DE)求解器因因素的组合而飙升:计算进步使其优化更具易行,它们处理高维问题的能力,容易解释他们的模型等。然而,几乎所有NN De Solvers患有基本限制:他们使用损耗函数训练,这些函数仅依赖于隐含地依赖于与估计相关的错误。因此,解决方案估计的验证和错误分析需要了解真正的解决方案。实际上,如果真正的解决方案是未知的,我们通常会减少到简单地希望“足够低”的损失意味着“足够的”错误,因为两者之间的显式关系不可用/良好定义。在这项工作中,我们描述了一种有效构建神经网络微分方程求解器的误差估计和校正的一般策略。我们的方法不需要推进真正解决方案的知识,并获得丢失功能与与解决方案估计相关的错误之间的显式关系。反过来,这些明确的关系直接允许我们估计和正确的错误。
translated by 谷歌翻译
对应用机器学习来研究动态系统有一波兴趣。特别地,已经应用神经网络来解决运动方程,因此追踪系统的演变。与神经网络和机器学习的其他应用相反,动态系统 - 根据其潜在的对称 - 具有诸如能量,动量和角动量的不变性。传统的数值迭代方法通常违反这些保护法,在时间上传播误差,并降低方法的可预测性。我们介绍了一个汉密尔顿神经网络,用于解决控制动态系统的微分方程。这种无监督的模型是学习解决方案,可以相同地满足哈密尔顿方程,因此哈密尔顿方程式满足。一旦优化了,所提出的架构被认为是一种杂项单元,因为引入了高效的参数的解决方案。另外,通过共享网络参数并选择适当的激活函数的选择大大提高了网络的可预测性。派生错误分析,并指出数值误差取决于整体网络性能。然后采用辛结构来解决非线性振荡器的方程和混沌HENON-HENEL动态系统。在两个系统中,杂项欧拉集成商需要两个订单比HAMILTONIAN网络更多的评估点,以便在预测的相空间轨迹中获得相同的数值误差顺序。
translated by 谷歌翻译
Artificial Intelligence (AI) is having a tremendous impact across most areas of science. Applications of AI in healthcare have the potential to improve our ability to detect, diagnose, prognose, and intervene on human disease. For AI models to be used clinically, they need to be made safe, reproducible and robust, and the underlying software framework must be aware of the particularities (e.g. geometry, physiology, physics) of medical data being processed. This work introduces MONAI, a freely available, community-supported, and consortium-led PyTorch-based framework for deep learning in healthcare. MONAI extends PyTorch to support medical data, with a particular focus on imaging, and provide purpose-specific AI model architectures, transformations and utilities that streamline the development and deployment of medical AI models. MONAI follows best practices for software-development, providing an easy-to-use, robust, well-documented, and well-tested software framework. MONAI preserves the simple, additive, and compositional approach of its underlying PyTorch libraries. MONAI is being used by and receiving contributions from research, clinical and industrial teams from around the world, who are pursuing applications spanning nearly every aspect of healthcare.
translated by 谷歌翻译
Designing experiments often requires balancing between learning about the true treatment effects and earning from allocating more samples to the superior treatment. While optimal algorithms for the Multi-Armed Bandit Problem (MABP) provide allocation policies that optimally balance learning and earning, they tend to be computationally expensive. The Gittins Index (GI) is a solution to the MABP that can simultaneously attain optimality and computationally efficiency goals, and it has been recently used in experiments with Bernoulli and Gaussian rewards. For the first time, we present a modification of the GI rule that can be used in experiments with exponentially-distributed rewards. We report its performance in simulated 2- armed and 3-armed experiments. Compared to traditional non-adaptive designs, our novel GI modified design shows operating characteristics comparable in learning (e.g. statistical power) but substantially better in earning (e.g. direct benefits). This illustrates the potential that designs using a GI approach to allocate participants have to improve participant benefits, increase efficiencies, and reduce experimental costs in adaptive multi-armed experiments with exponential rewards.
translated by 谷歌翻译
Quadruped robots are currently used in industrial robotics as mechanical aid to automate several routine tasks. However, presently, the usage of such a robot in a domestic setting is still very much a part of the research. This paper discusses the understanding and virtual simulation of such a robot capable of detecting and understanding human emotions, generating its gait, and responding via sounds and expression on a screen. To this end, we use a combination of reinforcement learning and software engineering concepts to simulate a quadruped robot that can understand emotions, navigate through various terrains and detect sound sources, and respond to emotions using audio-visual feedback. This paper aims to establish the framework of simulating a quadruped robot that is emotionally intelligent and can primarily respond to audio-visual stimuli using motor or audio response. The emotion detection from the speech was not as performant as ERANNs or Zeta Policy learning, still managing an accuracy of 63.5%. The video emotion detection system produced results that are almost at par with the state of the art, with an accuracy of 99.66%. Due to its "on-policy" learning process, the PPO algorithm was extremely rapid to learn, allowing the simulated dog to demonstrate a remarkably seamless gait across the different cadences and variations. This enabled the quadruped robot to respond to generated stimuli, allowing us to conclude that it functions as predicted and satisfies the aim of this work.
translated by 谷歌翻译
Real-world robotic grasping can be done robustly if a complete 3D Point Cloud Data (PCD) of an object is available. However, in practice, PCDs are often incomplete when objects are viewed from few and sparse viewpoints before the grasping action, leading to the generation of wrong or inaccurate grasp poses. We propose a novel grasping strategy, named 3DSGrasp, that predicts the missing geometry from the partial PCD to produce reliable grasp poses. Our proposed PCD completion network is a Transformer-based encoder-decoder network with an Offset-Attention layer. Our network is inherently invariant to the object pose and point's permutation, which generates PCDs that are geometrically consistent and completed properly. Experiments on a wide range of partial PCD show that 3DSGrasp outperforms the best state-of-the-art method on PCD completion tasks and largely improves the grasping success rate in real-world scenarios. The code and dataset will be made available upon acceptance.
translated by 谷歌翻译
When robots learn reward functions using high capacity models that take raw state directly as input, they need to both learn a representation for what matters in the task -- the task ``features" -- as well as how to combine these features into a single objective. If they try to do both at once from input designed to teach the full reward function, it is easy to end up with a representation that contains spurious correlations in the data, which fails to generalize to new settings. Instead, our ultimate goal is to enable robots to identify and isolate the causal features that people actually care about and use when they represent states and behavior. Our idea is that we can tune into this representation by asking users what behaviors they consider similar: behaviors will be similar if the features that matter are similar, even if low-level behavior is different; conversely, behaviors will be different if even one of the features that matter differs. This, in turn, is what enables the robot to disambiguate between what needs to go into the representation versus what is spurious, as well as what aspects of behavior can be compressed together versus not. The notion of learning representations based on similarity has a nice parallel in contrastive learning, a self-supervised representation learning technique that maps visually similar data points to similar embeddings, where similarity is defined by a designer through data augmentation heuristics. By contrast, in order to learn the representations that people use, so we can learn their preferences and objectives, we use their definition of similarity. In simulation as well as in a user study, we show that learning through such similarity queries leads to representations that, while far from perfect, are indeed more generalizable than self-supervised and task-input alternatives.
translated by 谷歌翻译
and widely used information measurement metric, particularly popularized for SSVEP- based Brain-Computer (BCI) interfaces. By combining speed and accuracy into a single-valued parameter, this metric aids in the evaluation and comparison of various target identification algorithms across different BCI communities. To accurately depict performance and inspire an end-to-end design for futuristic BCI designs, a more thorough examination and definition of ITR is therefore required. We model the symbiotic communication medium, hosted by the retinogeniculate visual pathway, as a discrete memoryless channel and use the modified capacity expressions to redefine the ITR. We use graph theory to characterize the relationship between the asymmetry of the transition statistics and the ITR gain with the new definition, leading to potential bounds on data rate performance. On two well-known SSVEP datasets, we compared two cutting-edge target identification methods. Results indicate that the induced DM channel asymmetry has a greater impact on the actual perceived ITR than the change in input distribution. Moreover, it is demonstrated that the ITR gain under the new definition is inversely correlated with the asymmetry in the channel transition statistics. Individual input customizations are further shown to yield perceived ITR performance improvements. An algorithm is proposed to find the capacity of binary classification and further discussions are given to extend such results to ensemble techniques.We anticipate that the results of our study will contribute to the characterization of the highly dynamic BCI channel capacities, performance thresholds, and improved BCI stimulus designs for a tighter symbiosis between the human brain and computer systems while enhancing the efficiency of the underlying communication resources.
translated by 谷歌翻译
A step-search sequential quadratic programming method is proposed for solving nonlinear equality constrained stochastic optimization problems. It is assumed that constraint function values and derivatives are available, but only stochastic approximations of the objective function and its associated derivatives can be computed via inexact probabilistic zeroth- and first-order oracles. Under reasonable assumptions, a high-probability bound on the iteration complexity of the algorithm to approximate first-order stationarity is derived. Numerical results on standard nonlinear optimization test problems illustrate the advantages and limitations of our proposed method.
translated by 谷歌翻译