天文瞬态是在各种时间尺度变得暂时更亮的恒星物体,并导致宇宙学和天文学中的一些最重要的发现。其中一些瞬变是被称为超新星的爆炸物的爆炸性死亡,而其他瞬间是罕见的,异国情调的,或完全是新的令人兴奋的恒星爆炸。新的天文天空调查正在观察前所未有的多波长瞬变数量,在视觉上识别新的和有趣的瞬态的标准方法不可行。为了满足这一需求,我们提出了两种新的方法,旨在实时快速,自动地自动检测异常瞬态光线曲线。两种方法都基于简单的想法,如果可以精确建模来自已知瞬态频体群体的光曲线,则从模型预测的任何偏差可能是异常的。第一方法是使用时间卷积网络(TCN)建造的概率神经网络,第二个是瞬态的可解释的贝叶斯参数模型。我们展示了神经网络的灵活性,使它们成为许多回归任务的这种强大工具的属性,是与我们的参数模型相比时不太适合于异常检测的原因。
translated by 谷歌翻译
天文学家通常已经着手通过从头开始创建自己的表示来解决监督的机器学习问题。我们表明,经过训练的深度学习模型,可以回答每个星系动物园贴花问题问题,即学习星系的有意义的语义表示,这些语义表示对于从未训练过的新任务很有用。我们利用这些表示形式优于最近对研究大型星系样本至关重要的实际任务的方法。第一个任务是识别与查询星系相似的形态的星系。给定一个星系为人类分配了一个免费文本标签(例如“ #diffuse”),我们可以找到与大多数标签匹配该标签的星系。第二个任务是确定特定研究人员最有趣的异常。我们的方法在识别最有趣的100个异常(由Galaxy Zoo 2志愿者判断)方面是100%准确的。第三个任务是调整模型来仅使用少数新标记的星系解决新任务。与从陆地图像(ImageNet)或从头开始训练的模型相比,从我们的表示形式进行微调的模型可以更好地识别环形星系。我们用很少的新标签解决每个任务;一个(用于相似性搜索)或数百个(用于异常检测或微调)。这挑战了长期以来的观点,即深度监督方法需要新的大型标签数据集,以便在天文学中实际使用。为了帮助社区受益于我们验证的模型,我们发布了我们的微调代码Zoobot。没有先前经验的研究人员可以访问Zoobot。
translated by 谷歌翻译
Real-time individual endpoint prediction has always been a challenging task but of great clinic utility for both patients and healthcare providers. With 6,879 chronic kidney disease stage 4 (CKD4) patients as a use case, we explored the feasibility and performance of gated recurrent units with decay that models Weibull probability density function (GRU-D-Weibull) as a semi-parametric longitudinal model for real-time individual endpoint prediction. GRU-D-Weibull has a maximum C-index of 0.77 at 4.3 years of follow-up, compared to 0.68 achieved by competing models. The L1-loss of GRU-D-Weibull is ~66% of XGB(AFT), ~60% of MTLR, and ~30% of AFT model at CKD4 index date. The average absolute L1-loss of GRU-D-Weibull is around one year, with a minimum of 40% Parkes serious error after index date. GRU-D-Weibull is not calibrated and significantly underestimates true survival probability. Feature importance tests indicate blood pressure becomes increasingly important during follow-up, while eGFR and blood albumin are less important. Most continuous features have non-linear/parabola impact on predicted survival time, and the results are generally consistent with existing knowledge. GRU-D-Weibull as a semi-parametric temporal model shows advantages in built-in parameterization of missing, native support for asynchronously arrived measurement, capability of output both probability and point estimates at arbitrary time point for arbitrary prediction horizon, improved discrimination and point estimate accuracy after incorporating newly arrived data. Further research on its performance with more comprehensive input features, in-process or post-process calibration are warranted to benefit CKD4 or alike terminally-ill patients.
translated by 谷歌翻译
Humans use all of their senses to accomplish different tasks in everyday activities. In contrast, existing work on robotic manipulation mostly relies on one, or occasionally two modalities, such as vision and touch. In this work, we systematically study how visual, auditory, and tactile perception can jointly help robots to solve complex manipulation tasks. We build a robot system that can see with a camera, hear with a contact microphone, and feel with a vision-based tactile sensor, with all three sensory modalities fused with a self-attention model. Results on two challenging tasks, dense packing and pouring, demonstrate the necessity and power of multisensory perception for robotic manipulation: vision displays the global status of the robot but can often suffer from occlusion, audio provides immediate feedback of key moments that are even invisible, and touch offers precise local geometry for decision making. Leveraging all three modalities, our robotic system significantly outperforms prior methods.
translated by 谷歌翻译
Image analysis technologies empowered by artificial intelligence (AI) have proved images and videos to be an opportune source of data to learn about humpback whale (Megaptera novaeangliae) population sizes and dynamics. With the advent of social media, platforms such as YouTube present an abundance of video data across spatiotemporal contexts documenting humpback whale encounters from users worldwide. In our work, we focus on automating the classification of YouTube videos as relevant or irrelevant based on whether they document a true humpback whale encounter or not via deep learning. We use a CNN-RNN architecture pretrained on the ImageNet dataset for classification of YouTube videos as relevant or irrelevant. We achieve an average 85.7% accuracy, and 84.7% (irrelevant)/ 86.6% (relevant) F1 scores using five-fold cross validation for evaluation on the dataset. We show that deep learning can be used as a time-efficient step to make social media a viable source of image and video data for biodiversity assessments.
translated by 谷歌翻译
Recent work has shown that machine learning (ML) models can be trained to accurately forecast the dynamics of unknown chaotic dynamical systems. Such ML models can be used to produce both short-term predictions of the state evolution and long-term predictions of the statistical patterns of the dynamics (``climate''). Both of these tasks can be accomplished by employing a feedback loop, whereby the model is trained to predict forward one time step, then the trained model is iterated for multiple time steps with its output used as the input. In the absence of mitigating techniques, however, this technique can result in artificially rapid error growth, leading to inaccurate predictions and/or climate instability. In this article, we systematically examine the technique of adding noise to the ML model input during training as a means to promote stability and improve prediction accuracy. Furthermore, we introduce Linearized Multi-Noise Training (LMNT), a regularization technique that deterministically approximates the effect of many small, independent noise realizations added to the model input during training. Our case study uses reservoir computing, a machine-learning method using recurrent neural networks, to predict the spatiotemporal chaotic Kuramoto-Sivashinsky equation. We find that reservoir computers trained with noise or with LMNT produce climate predictions that appear to be indefinitely stable and have a climate very similar to the true system, while reservoir computers trained without regularization are unstable. Compared with other types of regularization that yield stability in some cases, we find that both short-term and climate predictions from reservoir computers trained with noise or with LMNT are substantially more accurate. Finally, we show that the deterministic aspect of our LMNT regularization facilitates fast hyperparameter tuning when compared to training with noise.
translated by 谷歌翻译
Human and robot partners increasingly need to work together to perform tasks as a team. Robots designed for such collaboration must reason about how their task-completion strategies interplay with the behavior and skills of their human team members as they coordinate on achieving joint goals. Our goal in this work is to develop a computational framework for robot adaptation to human partners in human-robot team collaborations. We first present an algorithm for autonomously recognizing available task-completion strategies by observing human-human teams performing a collaborative task. By transforming team actions into low dimensional representations using hidden Markov models, we can identify strategies without prior knowledge. Robot policies are learned on each of the identified strategies to construct a Mixture-of-Experts model that adapts to the task strategies of unseen human partners. We evaluate our model on a collaborative cooking task using an Overcooked simulator. Results of an online user study with 125 participants demonstrate that our framework improves the task performance and collaborative fluency of human-agent teams, as compared to state of the art reinforcement learning methods.
translated by 谷歌翻译
这项研究提出了一个基于移动网格参数化的端到端无监督的差异可变形登记框架。使用此参数化,可以使用其转换雅各布的决定因素和末端速度场的卷曲来建模。变形场的新模型具有三个重要优势。首先,它放松了对成本函数的显式正则化项和相应重量的需求。平滑度隐含在溶液中,从而导致物理上合理的变形场。其次,它通过适用于转换雅各布决定因素的明确约束来保证差异性。最后,它适用于心脏数据处理,因为该参数化的性质是根据​​径向和旋转成分定义变形场。通过在包括2D和3D心脏MRI扫描在内的三个不同数据集上评估拟议方法来研究算法的有效性。结果表明,所提出的框架在生成差异变换的同时优于现有的基于学习的方法和基于非学习的方法。
translated by 谷歌翻译
越来越需要在各种新的硬件平台上为不同任务部署机器学习。这样的部署场景需要应对多个挑战,包括确定可以实现合适的预测准确性(体系结构搜索)的模型体系结构,并找到有效的模型实施,以满足基础硬件特定的系统约束,例如延迟(系统优化搜索)。现有作品将架构搜索和系统优化搜索视为单独的问题,并将其顺序解决。在本文中,我们建议共同解决这些问题,并引入一种简单但有效的基线方法,称为Sonar,该方法交织了这两个搜索问题。 Sonar的目标是通过将早期停止应用于两个搜索过程来有效地优化预测准确性和推理潜伏期。我们对多个不同硬件后端的实验表明,Sonar识别出几乎最佳体系结构的速度比蛮力方法快30倍。
translated by 谷歌翻译
我们解决了受控生成小分子的任务,该任务需要在某些约束(例如,与参考分子相似)下找到具有所需特性的新分子。在这里,我们介绍了Molmim,这是一种用于学习信息丰富且聚集的潜在空间的小分子药物发现的概率自动编码器。 Molmim通过共同信息机(MIM)学习训练,并提供可变长度微笑字符串的固定长度表示。由于编码器模型可以通过无效样品的``孔''来学习表示形式,因此我们在这里提出了训练程序的新型扩展,该过程促进了促进密集的潜在空间,并允许模型从潜在代码的随机扰动中采样有效分子。我们提供了Molmim与几个可变大小和固定尺寸的编码器模型的彻底比较,这表明了Molmim的上一代,如有效性,独特性和新颖性而言。然后,我们利用CMA-E,一种天真的黑盒和无梯度的搜索算法,是Molmim的潜在空间来实现属性引导分子优化的任务。我们实现了最新的单个属性优化任务以及多目标优化的具有挑战性的任务,从而提高了先前的成功率SOTA超过5 \%。我们将强有力的结果归因于莫尔米姆的潜在表示,这些表示在潜在空间中聚集了相似的分子,而CMA-ES通常用作基线优化方法。我们还证明了莫尔米姆在计算有限的制度中有利,使其成为这种情况的有吸引力的模型。
translated by 谷歌翻译