我们检查了通过直播(OTA)聚合的联合学习(FL),移动用户(MUS)旨在借助聚合本地梯度的参数服务器(PS)在全球模型上达成共识。在OTA FL中,MUS在每个训练回合中使用本地数据训练他们的模型,并以未编码的方式使用相同的频带同时传输其梯度。根据超级梯度的接收信号,PS执行全局模型更新。尽管OTA FL的通信成本显着降低,但它容易受到不利的通道影响和噪声的影响。在接收器侧采用多个天线可以减少这些效果,但是对于远离PS的用户来说,路径损失仍然是一个限制因素。为了改善此问题,在本文中,我们提出了一种基于无线的层次FL方案,该方案使用中间服务器(ISS)在MUS更密集的区域形成簇。我们的计划利用OTA群集聚合与MUS与其相应的IS进行交流,而OTA全球聚合从ISS到PS。我们提出了针对所提出算法的收敛分析,并通过对使用ISS的衍生分析表达式和实验结果的数值评估显示,与单独使用较少的传输功率相比,利用ISS的结果比单独的OTA FL具有更快的收敛性和更好的性能。我们还使用不同数量的群集迭代以及不同数据集和数据分布来验证性能的结果。我们得出的结论是,群集聚集的最佳选择取决于MUS和集群之间的数据分布。
translated by 谷歌翻译
通过无线通信信道联合学习(FL),具体地,考虑过空中(OTA)模型聚合框架。在OTA无线设置中,通过增加参数服务器(PS)的接收天线的数量来缓解不利的通道效果,该参数服务器(PS)执行模型聚合。然而,OTA FL的性能受到远离PS远离PS的移动用户(MU)的存在限制。在本文中,为了减轻这种限制,我们提出了分层的超空气联合学习(HotaF1),它利用中介服务器(是)在Mus附近形成集群。我们为建议的设置提供了收敛性分析,并通过理论和实验结果证明了在全局聚集之前每个群集的局部聚合导致更好的性能和更快的收敛性比OTA FL更快。
translated by 谷歌翻译
展开的神经网络最近实现了最先进的MRI重建。这些网络通过在基于物理的一致性和基于神经网络的正则化之间交替来展开迭代优化算法。但是,它们需要大型神经网络的几次迭代来处理高维成像任务,例如3D MRI。这限制了基于反向传播的传统训练算法,这是由于较大的记忆力和计算梯度和存储中间激活的计算要求。为了应对这一挑战,我们提出了加速MRI(GLEAM)重建的贪婪学习,这是一种高维成像设置的有效培训策略。 GLEAM将端到端网络拆分为脱钩的网络模块。每个模块都以贪婪的方式优化,并通过脱钩的梯度更新,从而减少了训练过程中的内存足迹。我们表明,可以在多个图形处理单元(GPU)上并行执行解耦梯度更新,以进一步减少训练时间。我们介绍了2D和3D数据集的实验,包括多线圈膝,大脑和动态心脏Cine MRI。我们观察到:i)闪闪发光的概括以及最先进的记忆效率基线,例如具有相同内存足迹的梯度检查点和可逆网络,但训练速度更快1.3倍; ii)对于相同的内存足迹,闪光在2D中产生1.1dB PSNR的增益,而3D在端到端基线中产生1.8 dB。
translated by 谷歌翻译
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.
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
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.
translated by 谷歌翻译
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.
translated by 谷歌翻译
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/ .
translated by 谷歌翻译
We derive a set of causal deep neural networks whose architectures are a consequence of tensor (multilinear) factor analysis. Forward causal questions are addressed with a neural network architecture composed of causal capsules and a tensor transformer. The former estimate a set of latent variables that represent the causal factors, and the latter governs their interaction. Causal capsules and tensor transformers may be implemented using shallow autoencoders, but for a scalable architecture we employ block algebra and derive a deep neural network composed of a hierarchy of autoencoders. An interleaved kernel hierarchy preprocesses the data resulting in a hierarchy of kernel tensor factor models. Inverse causal questions are addressed with a neural network that implements multilinear projection and estimates the causes of effects. As an alternative to aggressive bottleneck dimension reduction or regularized regression that may camouflage an inherently underdetermined inverse problem, we prescribe modeling different aspects of the mechanism of data formation with piecewise tensor models whose multilinear projections are well-defined and produce multiple candidate solutions. Our forward and inverse neural network architectures are suitable for asynchronous parallel computation.
translated by 谷歌翻译
Landing an unmanned aerial vehicle unmanned aerial vehicle (UAV) on top of an unmanned surface vehicle (USV) in harsh open waters is a challenging problem, owing to forces that can damage the UAV due to a severe roll and/or pitch angle of the USV during touchdown. To tackle this, we propose a novel model predictive control (MPC) approach enabling a UAV to land autonomously on a USV in these harsh conditions. The MPC employs a novel objective function and an online decomposition of the oscillatory motion of the vessel to predict, attempt, and accomplish the landing during near-zero tilt of the landing platform. The nonlinear prediction of the motion of the vessel is performed using visual data from an onboard camera. Therefore, the system does not require any communication with the USV or a control station. The proposed method was analyzed in numerous robotics simulations in harsh and extreme conditions and further validated in various real-world scenarios.
translated by 谷歌翻译