在计算机视觉中,对现实世界图像的自我监督,类别不足的分割是一个具有挑战性的开放问题。在这里,我们通过基于Spelke对象的认知科学概念来展示如何从运动自学学习中学习静态分组先验:一组可以一起移动的物理内容。我们介绍了兴奋性抑制段提取网络(EISEN),该网络学会从基于运动的训练信号中提取成对的亲和力图,以供静态场景。然后,艾森使用新颖的图形传播和竞争网络从亲和力产生细分市场。在训练过程中,进行相关运动的对象(例如机器人臂和移动的对象)被引导过程解耦:Eisen解释了它已经学会了细分的对象的运动。我们表明,艾森(Eisen)在挑战合成和现实世界的机器人数据集上进行了自我监督的图像分割方面取得了重大改进。
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在这项工作中,我们探讨了随机梯度下降(SGD)训练的深神经网络的限制动态。如前所述,长时间的性能融合,网络继续通过参数空间通过一个异常扩散的过程,其中距离在具有非活动指数的梯度更新的数量中增加距离。我们揭示了优化的超公数,梯度噪声结构之间的复杂相互作用,以及在训练结束时解释这种异常扩散的Hessian矩阵。为了构建这种理解,我们首先为SGD推导出一个连续时间模型,具有有限的学习速率和批量尺寸,作为欠下的Langevin方程。我们在线性回归中研究了这个方程,我们可以为参数的相位空间动态和它们的瞬时速度来得出精确的分析表达式,从初始化到实用性。使用Fokker-Planck方程,我们表明驾驶这些动态的关键成分不是原始的训练损失,而是修改的损失的组合,其隐含地规则地规范速度和概率电流,这导致相位空间中的振荡。我们在ImageNet培训的Reset-18模型的动态中确定了这种理论的定性和定量预测。通过统计物理的镜头,我们揭示了SGD培训的深神经网络的异常限制动态的机制来源。
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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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我们介绍了ThreedWorld(TDW),是交互式多模态物理模拟的平台。 TDW能够模拟高保真感官数据和富裕的3D环境中的移动代理和对象之间的物理交互。独特的属性包括:实时近光 - 真实图像渲染;对象和环境库,以及他们定制的例程;有效构建新环境课程的生成程序;高保真音频渲染;各种材料类型的现实物理相互作用,包括布料,液体和可变形物体;可定制的代理体现AI代理商;并支持与VR设备的人类交互。 TDW的API使多个代理能够在模拟中进行交互,并返回一系列表示世界状态的传感器和物理数据。我们在计算机视觉,机器学习和认知科学中的新兴的研究方向上提供了通过TDW的初始实验,包括多模态物理场景理解,物理动态预测,多代理交互,像孩子一样学习的模型,并注意研究人类和神经网络。
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Unsupervised approaches to learning in neural networks are of substantial interest for furthering artificial intelligence, both because they would enable the training of networks without the need for large numbers of expensive annotations, and because they would be better models of the kind of general-purpose learning deployed by humans. However, unsupervised networks have long lagged behind the performance of their supervised counterparts, especially in the domain of large-scale visual recognition. Recent developments in training deep convolutional embeddings to maximize non-parametric instance separation and clustering objectives have shown promise in closing this gap. Here, we describe a method that trains an embedding function to maximize a metric of local aggregation, causing similar data instances to move together in the embedding space, while allowing dissimilar instances to separate. This aggregation metric is dynamic, allowing soft clusters of different scales to emerge. We evaluate our procedure on several large-scale visual recognition datasets, achieving state-of-the-art unsupervised transfer learning performance on object recognition in ImageNet, scene recognition in Places 205, and object detection in PASCAL VOC.
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The performance of inertial navigation systems is largely dependent on the stable flow of external measurements and information to guarantee continuous filter updates and bind the inertial solution drift. Platforms in different operational environments may be prevented at some point from receiving external measurements, thus exposing their navigation solution to drift. Over the years, a wide variety of works have been proposed to overcome this shortcoming, by exploiting knowledge of the system current conditions and turning it into an applicable source of information to update the navigation filter. This paper aims to provide an extensive survey of information aided navigation, broadly classified into direct, indirect, and model aiding. Each approach is described by the notable works that implemented its concept, use cases, relevant state updates, and their corresponding measurement models. By matching the appropriate constraint to a given scenario, one will be able to improve the navigation solution accuracy, compensate for the lost information, and uncover certain internal states, that would otherwise remain unobservable.
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We consider infinite horizon Markov decision processes (MDPs) with fast-slow structure, meaning that certain parts of the state space move "fast" (and in a sense, are more influential) while other parts transition more "slowly." Such structure is common in real-world problems where sequential decisions need to be made at high frequencies, yet information that varies at a slower timescale also influences the optimal policy. Examples include: (1) service allocation for a multi-class queue with (slowly varying) stochastic costs, (2) a restless multi-armed bandit with an environmental state, and (3) energy demand response, where both day-ahead and real-time prices play a role in the firm's revenue. Models that fully capture these problems often result in MDPs with large state spaces and large effective time horizons (due to frequent decisions), rendering them computationally intractable. We propose an approximate dynamic programming algorithmic framework based on the idea of "freezing" the slow states, solving a set of simpler finite-horizon MDPs (the lower-level MDPs), and applying value iteration (VI) to an auxiliary MDP that transitions on a slower timescale (the upper-level MDP). We also extend the technique to a function approximation setting, where a feature-based linear architecture is used. On the theoretical side, we analyze the regret incurred by each variant of our frozen-state approach. Finally, we give empirical evidence that the frozen-state approach generates effective policies using just a fraction of the computational cost, while illustrating that simply omitting slow states from the decision modeling is often not a viable heuristic.
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In the present work we propose an unsupervised ensemble method consisting of oblique trees that can address the task of auto-encoding, namely Oblique Forest AutoEncoders (briefly OF-AE). Our method is a natural extension of the eForest encoder introduced in [1]. More precisely, by employing oblique splits consisting in multivariate linear combination of features instead of the axis-parallel ones, we will devise an auto-encoder method through the computation of a sparse solution of a set of linear inequalities consisting of feature values constraints. The code for reproducing our results is available at https://github.com/CDAlecsa/Oblique-Forest-AutoEncoders.
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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.
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While the capabilities of autonomous systems have been steadily improving in recent years, these systems still struggle to rapidly explore previously unknown environments without the aid of GPS-assisted navigation. The DARPA Subterranean (SubT) Challenge aimed to fast track the development of autonomous exploration systems by evaluating their performance in real-world underground search-and-rescue scenarios. Subterranean environments present a plethora of challenges for robotic systems, such as limited communications, complex topology, visually-degraded sensing, and harsh terrain. The presented solution enables long-term autonomy with minimal human supervision by combining a powerful and independent single-agent autonomy stack, with higher level mission management operating over a flexible mesh network. The autonomy suite deployed on quadruped and wheeled robots was fully independent, freeing the human supervision to loosely supervise the mission and make high-impact strategic decisions. We also discuss lessons learned from fielding our system at the SubT Final Event, relating to vehicle versatility, system adaptability, and re-configurable communications.
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