大脑磁共振成像(MRI)扫描的自动分割和体积对于诊断帕金森氏病(PD)和帕金森氏症综合症(P-Plus)至关重要。为了提高诊断性能,我们在大脑分割中采用了深度学习(DL)模型,并将其性能与金标准的非DL方法进行了比较。我们收集了健康对照组(n = 105)和PD患者(n = 105),多个全身性萎缩(n = 132)和渐进性超核麻痹(n = 69)的大脑MRI扫描。 2020.使用金标准的非DL模型FreeSurfer(FS),我们对六个脑结构进行了分割:中脑,PON,CAUDATE,CAUDATE,PUTATATE,pALLIDUM和THIRD CNTRICLE,并将其视为DL模型的注释数据,代表性V -net和unet。计算了分化正常,PD和P-Plus病例的曲线下的骰子分数和面积。每位患者六个大脑结构的V-NET和UNETR的分割时间分别为3.48 +-0.17和48.14 +-0.97 s,比FS(15,735 +-1.07 s)快至少300倍。两种DL模型的骰子得分都足够高(> 0.85),它们的疾病分类AUC优于FS。为了分类正常与P-Plus和PD与多个全身性萎缩(小脑型)的分类,DL模型和FS显示出高于0.8的AUC。 DL显着减少了分析时间,而不会损害大脑分割和差异诊断的性能。我们的发现可能有助于在临床环境中采用DL脑MRI分割并提高大脑研究。
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尖峰神经网络(SNNS)模仿大脑中信息传播可以通过离散和稀疏的尖峰来能够能够通过离散和稀疏的尖峰来处理时空信息,从而受到相当大的关注。为了提高SNN的准确性和能源效率,大多数以前的研究仅集中在训练方法上,并且很少研究建筑的效果。我们研究了先前研究中使用的设计选择,从尖峰的准确性和数量来看,发现它们不是最适合SNN的。为了进一步提高准确性并减少SNN产生的尖峰,我们提出了一个称为Autosnn的尖峰感知神经体系结构搜索框架。我们定义一个搜索空间,该搜索空间由架构组成,而没有不良的设计选择。为了启用Spike-Aware Architecture搜索,我们引入了一种健身,该健身既考虑尖峰的准确性和数量。 Autosnn成功地搜索了SNN体系结构,这些体系结构在准确性和能源效率方面都超过了手工制作的SNN。我们彻底证明了AutoSNN在包括神经形态数据集在内的各种数据集上的有效性。
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最近最近的半监督学习(SSL)研究建立了教师学生的建筑,并通过教师产生的监督信号训练学生网络。数据增强策略在SSL框架中发挥着重要作用,因为很难在不丢失标签信息的情况下创建弱强度增强的输入对。特别是当将SSL扩展到半监督对象检测(SSOD)时,许多与图像几何和插值正则化相关的强大增强方法很难利用,因为它们可能损坏了对象检测任务中的边界框的位置信息。为解决此问题,我们介绍了一个简单但有效的数据增强方法,MIX / unmix(MUM),其中解密为SSOD框架的混合图像块的瓷砖。我们所提出的方法使混合输入图像块进行混合输入图像块,并在特征空间中重建它们。因此,妈妈可以从未插入的伪标签享受插值正则化效果,并成功地生成有意义的弱强对。此外,妈妈可以容易地配备各种SSOD方法。在MS-Coco和Pascal VOC数据集上的广泛实验通过在所有测试的SSOD基准协议中始终如一地提高基线的地图性能,证明了妈妈的优越性。
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The 3D-aware image synthesis focuses on conserving spatial consistency besides generating high-resolution images with fine details. Recently, Neural Radiance Field (NeRF) has been introduced for synthesizing novel views with low computational cost and superior performance. While several works investigate a generative NeRF and show remarkable achievement, they cannot handle conditional and continuous feature manipulation in the generation procedure. In this work, we introduce a novel model, called Class-Continuous Conditional Generative NeRF ($\text{C}^{3}$G-NeRF), which can synthesize conditionally manipulated photorealistic 3D-consistent images by projecting conditional features to the generator and the discriminator. The proposed $\text{C}^{3}$G-NeRF is evaluated with three image datasets, AFHQ, CelebA, and Cars. As a result, our model shows strong 3D-consistency with fine details and smooth interpolation in conditional feature manipulation. For instance, $\text{C}^{3}$G-NeRF exhibits a Fr\'echet Inception Distance (FID) of 7.64 in 3D-aware face image synthesis with a $\text{128}^{2}$ resolution. Additionally, we provide FIDs of generated 3D-aware images of each class of the datasets as it is possible to synthesize class-conditional images with $\text{C}^{3}$G-NeRF.
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Cellular automata (CA) captivate researchers due to teh emergent, complex individualized behavior that simple global rules of interaction enact. Recent advances in the field have combined CA with convolutional neural networks to achieve self-regenerating images. This new branch of CA is called neural cellular automata [1]. The goal of this project is to use the idea of idea of neural cellular automata to grow prediction machines. We place many different convolutional neural networks in a grid. Each conv net cell outputs a prediction of what the next state will be, and minimizes predictive error. Cells received their neighbors' colors and fitnesses as input. Each cell's fitness score described how accurate its predictions were. Cells could also move to explore their environment and some stochasticity was applied to movement.
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There is a dramatic shortage of skilled labor for modern vineyards. The Vinum project is developing a mobile robotic solution to autonomously navigate through vineyards for winter grapevine pruning. This necessitates an autonomous navigation stack for the robot pruning a vineyard. The Vinum project is using the quadruped robot HyQReal. This paper introduces an architecture for a quadruped robot to autonomously move through a vineyard by identifying and approaching grapevines for pruning. The higher level control is a state machine switching between searching for destination positions, autonomously navigating towards those locations, and stopping for the robot to complete a task. The destination points are determined by identifying grapevine trunks using instance segmentation from a Mask Region-Based Convolutional Neural Network (Mask-RCNN). These detections are sent through a filter to avoid redundancy and remove noisy detections. The combination of these features is the basis for the proposed architecture.
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Feature selection helps reduce data acquisition costs in ML, but the standard approach is to train models with static feature subsets. Here, we consider the dynamic feature selection (DFS) problem where a model sequentially queries features based on the presently available information. DFS is often addressed with reinforcement learning (RL), but we explore a simpler approach of greedily selecting features based on their conditional mutual information. This method is theoretically appealing but requires oracle access to the data distribution, so we develop a learning approach based on amortized optimization. The proposed method is shown to recover the greedy policy when trained to optimality and outperforms numerous existing feature selection methods in our experiments, thus validating it as a simple but powerful approach for this problem.
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In this paper, we learn a diffusion model to generate 3D data on a scene-scale. Specifically, our model crafts a 3D scene consisting of multiple objects, while recent diffusion research has focused on a single object. To realize our goal, we represent a scene with discrete class labels, i.e., categorical distribution, to assign multiple objects into semantic categories. Thus, we extend discrete diffusion models to learn scene-scale categorical distributions. In addition, we validate that a latent diffusion model can reduce computation costs for training and deploying. To the best of our knowledge, our work is the first to apply discrete and latent diffusion for 3D categorical data on a scene-scale. We further propose to perform semantic scene completion (SSC) by learning a conditional distribution using our diffusion model, where the condition is a partial observation in a sparse point cloud. In experiments, we empirically show that our diffusion models not only generate reasonable scenes, but also perform the scene completion task better than a discriminative model. Our code and models are available at https://github.com/zoomin-lee/scene-scale-diffusion
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We introduce a new tool for stochastic convex optimization (SCO): a Reweighted Stochastic Query (ReSQue) estimator for the gradient of a function convolved with a (Gaussian) probability density. Combining ReSQue with recent advances in ball oracle acceleration [CJJJLST20, ACJJS21], we develop algorithms achieving state-of-the-art complexities for SCO in parallel and private settings. For a SCO objective constrained to the unit ball in $\mathbb{R}^d$, we obtain the following results (up to polylogarithmic factors). We give a parallel algorithm obtaining optimization error $\epsilon_{\text{opt}}$ with $d^{1/3}\epsilon_{\text{opt}}^{-2/3}$ gradient oracle query depth and $d^{1/3}\epsilon_{\text{opt}}^{-2/3} + \epsilon_{\text{opt}}^{-2}$ gradient queries in total, assuming access to a bounded-variance stochastic gradient estimator. For $\epsilon_{\text{opt}} \in [d^{-1}, d^{-1/4}]$, our algorithm matches the state-of-the-art oracle depth of [BJLLS19] while maintaining the optimal total work of stochastic gradient descent. We give an $(\epsilon_{\text{dp}}, \delta)$-differentially private algorithm which, given $n$ samples of Lipschitz loss functions, obtains near-optimal optimization error and makes $\min(n, n^2\epsilon_{\text{dp}}^2 d^{-1}) + \min(n^{4/3}\epsilon_{\text{dp}}^{1/3}, (nd)^{2/3}\epsilon_{\text{dp}}^{-1})$ queries to the gradients of these functions. In the regime $d \le n \epsilon_{\text{dp}}^{2}$, where privacy comes at no cost in terms of the optimal loss up to constants, our algorithm uses $n + (nd)^{2/3}\epsilon_{\text{dp}}^{-1}$ queries and improves recent advancements of [KLL21, AFKT21]. In the moderately low-dimensional setting $d \le \sqrt n \epsilon_{\text{dp}}^{3/2}$, our query complexity is near-linear.
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We propose a new causal inference framework to learn causal effects from multiple, decentralized data sources in a federated setting. We introduce an adaptive transfer algorithm that learns the similarities among the data sources by utilizing Random Fourier Features to disentangle the loss function into multiple components, each of which is associated with a data source. The data sources may have different distributions; the causal effects are independently and systematically incorporated. The proposed method estimates the similarities among the sources through transfer coefficients, and hence requiring no prior information about the similarity measures. The heterogeneous causal effects can be estimated with no sharing of the raw training data among the sources, thus minimizing the risk of privacy leak. We also provide minimax lower bounds to assess the quality of the parameters learned from the disparate sources. The proposed method is empirically shown to outperform the baselines on decentralized data sources with dissimilar distributions.
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