Platelet products are both expensive and have very short shelf lives. As usage rates for platelets are highly variable, the effective management of platelet demand and supply is very important yet challenging. The primary goal of this paper is to present an efficient forecasting model for platelet demand at Canadian Blood Services (CBS). To accomplish this goal, four different demand forecasting methods, ARIMA (Auto Regressive Moving Average), Prophet, lasso regression (least absolute shrinkage and selection operator) and LSTM (Long Short-Term Memory) networks are utilized and evaluated. We use a large clinical dataset for a centralized blood distribution centre for four hospitals in Hamilton, Ontario, spanning from 2010 to 2018 and consisting of daily platelet transfusions along with information such as the product specifications, the recipients' characteristics, and the recipients' laboratory test results. This study is the first to utilize different methods from statistical time series models to data-driven regression and a machine learning technique for platelet transfusion using clinical predictors and with different amounts of data. We find that the multivariate approaches have the highest accuracy in general, however, if sufficient data are available, a simpler time series approach such as ARIMA appears to be sufficient. We also comment on the approach to choose clinical indicators (inputs) for the multivariate models.
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我们提出了一种分层骨骼引导的运动计划算法来指导移动机器人。良好的骨骼绘制了C空间子空间的连接性,该子空间包含显着的自由度,并能够引导计划者快速找到所需的解决方案。但是,有时骨骼并不能密切代表自由的C空间,这通常会误导当前的骨架引导的计划者。分层骨骼指导的计划策略逐渐放松其对工作区骨骼的依赖,因为C空间被采样,从而逐渐返回了一条次优路径,该路径在标准骨架引导的算法中无法保证。与标准骨骼指导计划者和其他懒惰计划策略的实验比较显示了路线图施工时间的显着改善,同时保持混乱环境中多电量问题的路径质量。
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用于卫星图像分析的计算机视觉算法的创新可以使我们能够在行星层面探索全球挑战,例如城市化和土地利用变化。但是,当试图复制将这些分析推向新领域的模型时,尤其是在发展中国家的模型时,域转移问题是一个普遍的情况。如果模型是通过一个位置的图像和标签训练的,则通常不会很好地概括到图像和数据分布不同的新位置。在这项工作中,我们考虑了我们有一个大型卫星图像场景的设置,我们希望在该场景上解决一个应用问题 - 构建足迹细分。在这里,我们不一定需要担心创建一个概括过我们场景边界的模型,而是可以训练本地模型。我们表明,使用非常高分辨率(0.5m/px)卫星图像解决建筑细分问题需要的标签很少。我们只有527个稀疏多边形注释(相当于1500 x 1500名被标记的像素)训练的最佳型号,召回了0.87的持有足迹,R2的r2为0.93视窗。我们将模型应用于约旦安曼(Amman)的高分辨率图像中,在一项有关城市变化检测的案例研究中。
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当加强学习以稀疏的奖励应用时,代理必须花费很长时间探索未知环境而没有任何学习信号。抽象是一种为代理提供在潜在空间中过渡的内在奖励的方法。先前的工作着重于密集的连续潜在空间,或要求用户手动提供表示形式。我们的方法是第一个自动学习基础环境的离散抽象的方法。此外,我们的方法使用端到端可训练的正规后继代表模型在任意输入空间上起作用。对于抽象状态之间的过渡,我们以选项的形式训练一组时间扩展的动作,即动作抽象。我们提出的算法,离散的国家行动抽象(DSAA),在训练这些选项之间进行迭代交换,并使用它们有效地探索更多环境以改善状态抽象。结果,我们的模型不仅对转移学习,而且在在线学习环境中有用。我们从经验上表明,与基线加强学习算法相比,我们的代理能够探索环境并更有效地解决任务。我们的代码可在\ url {https://github.com/amnonattali/dsaa}上公开获得。
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尽管当前的视觉算法在许多具有挑战性的任务上都表现出色,但尚不清楚他们如何理解现实世界环境的物理动态。在这里,我们介绍了Physion,一种数据集和基准,用于严格评估预测物理场景如何随着时间而发展的能力。我们的数据集具有对各种物理现象的现实模拟,包括刚性和软体体碰撞,稳定的多对象配置,滚动,滑动和弹丸运动,因此比以前的基准提供了更全面的挑战。我们使用Physion来基准一套模型,其体系结构,学习目标,投入输出结构和培训数据各不相同。同时,我们在同一场景上获得了人类预测行为的精确测量,从而使我们能够直接评估任何模型能够近似人类行为的效果。我们发现,学习以对象为中心的表示的视觉算法通常优于那些没有人的表现,但仍未达到人类绩效。另一方面,绘制具有直接访问物理状态信息的神经网络的表现效果更好,并且做出与人类制作的预测更相似。这些结果表明,提取场景的物理表征是在视力算法中实现人类水平和类似人类的物理理解的主要瓶颈。我们已公开发布了所有数据和代码,以促进使用物理以完全可重现的方式对其他模型进行基准测试,从而使对视觉算法的进度进行系统的评估,这些算法像人们一样坚固地了解物理环境。
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The recent increase in public and academic interest in preserving biodiversity has led to the growth of the field of conservation technology. This field involves designing and constructing tools that utilize technology to aid in the conservation of wildlife. In this article, we will use case studies to demonstrate the importance of designing conservation tools with human-wildlife interaction in mind and provide a framework for creating successful tools. These case studies include a range of complexities, from simple cat collars to machine learning and game theory methodologies. Our goal is to introduce and inform current and future researchers in the field of conservation technology and provide references for educating the next generation of conservation technologists. Conservation technology not only has the potential to benefit biodiversity but also has broader impacts on fields such as sustainability and environmental protection. By using innovative technologies to address conservation challenges, we can find more effective and efficient solutions to protect and preserve our planet's resources.
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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.
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While the brain connectivity network can inform the understanding and diagnosis of developmental dyslexia, its cause-effect relationships have not yet enough been examined. Employing electroencephalography signals and band-limited white noise stimulus at 4.8 Hz (prosodic-syllabic frequency), we measure the phase Granger causalities among channels to identify differences between dyslexic learners and controls, thereby proposing a method to calculate directional connectivity. As causal relationships run in both directions, we explore three scenarios, namely channels' activity as sources, as sinks, and in total. Our proposed method can be used for both classification and exploratory analysis. In all scenarios, we find confirmation of the established right-lateralized Theta sampling network anomaly, in line with the temporal sampling framework's assumption of oscillatory differences in the Theta and Gamma bands. Further, we show that this anomaly primarily occurs in the causal relationships of channels acting as sinks, where it is significantly more pronounced than when only total activity is observed. In the sink scenario, our classifier obtains 0.84 and 0.88 accuracy and 0.87 and 0.93 AUC for the Theta and Gamma bands, respectively.
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Variational autoencoders model high-dimensional data by positing low-dimensional latent variables that are mapped through a flexible distribution parametrized by a neural network. Unfortunately, variational autoencoders often suffer from posterior collapse: the posterior of the latent variables is equal to its prior, rendering the variational autoencoder useless as a means to produce meaningful representations. Existing approaches to posterior collapse often attribute it to the use of neural networks or optimization issues due to variational approximation. In this paper, we consider posterior collapse as a problem of latent variable non-identifiability. We prove that the posterior collapses if and only if the latent variables are non-identifiable in the generative model. This fact implies that posterior collapse is not a phenomenon specific to the use of flexible distributions or approximate inference. Rather, it can occur in classical probabilistic models even with exact inference, which we also demonstrate. Based on these results, we propose a class of latent-identifiable variational autoencoders, deep generative models which enforce identifiability without sacrificing flexibility. This model class resolves the problem of latent variable non-identifiability by leveraging bijective Brenier maps and parameterizing them with input convex neural networks, without special variational inference objectives or optimization tricks. Across synthetic and real datasets, latent-identifiable variational autoencoders outperform existing methods in mitigating posterior collapse and providing meaningful representations of the data.
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There are multiple scales of abstraction from which we can describe the same image, depending on whether we are focusing on fine-grained details or a more global attribute of the image. In brain mapping, learning to automatically parse images to build representations of both small-scale features (e.g., the presence of cells or blood vessels) and global properties of an image (e.g., which brain region the image comes from) is a crucial and open challenge. However, most existing datasets and benchmarks for neuroanatomy consider only a single downstream task at a time. To bridge this gap, we introduce a new dataset, annotations, and multiple downstream tasks that provide diverse ways to readout information about brain structure and architecture from the same image. Our multi-task neuroimaging benchmark (MTNeuro) is built on volumetric, micrometer-resolution X-ray microtomography images spanning a large thalamocortical section of mouse brain, encompassing multiple cortical and subcortical regions. We generated a number of different prediction challenges and evaluated several supervised and self-supervised models for brain-region prediction and pixel-level semantic segmentation of microstructures. Our experiments not only highlight the rich heterogeneity of this dataset, but also provide insights into how self-supervised approaches can be used to learn representations that capture multiple attributes of a single image and perform well on a variety of downstream tasks. Datasets, code, and pre-trained baseline models are provided at: https://mtneuro.github.io/ .
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