贝叶斯优化(BO)算法在涉及昂贵的黑盒功能的应用中表现出了显着的成功。传统上,BO被设置为一个顺序决策过程,该过程通过采集函数和先前的功能(例如高斯过程)来估计查询点的实用性。然而,最近,通过密度比率估计(BORE)对BO进行重新制定允许将采集函数重新诠释为概率二进制分类器,从而消除了对函数的显式先验和提高可伸缩性的需求。在本文中,我们介绍了对孔的遗憾和算法扩展的理论分析,并提高了不确定性估计。我们还表明,通过将问题重新提交为近似贝叶斯推断,可以自然地扩展到批处理优化设置。所得算法配备了理论性能保证,并在一系列实验中对其他批处理基本线进行了评估。
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糖尿病性视网膜病变(DR)是发达国家工人衰老人群中失明的主要原因之一,这是由于糖尿病的副作用降低了视网膜的血液供应。深度神经网络已被广泛用于自动化系统中,以在眼底图像上进行DR分类。但是,这些模型需要大量带注释的图像。在医疗领域,专家的注释昂贵,乏味且耗时。结果,提供了有限数量的注释图像。本文提出了一种半监督的方法,该方法利用未标记的图像和标记的图像来训练一种检测糖尿病性视网膜病的模型。提出的方法通过自我监督的学习使用无监督的预告片,然后使用一小部分标记的图像和知识蒸馏来监督微调,以提高分类任务的性能。在Eyepacs测试和Messidor-2数据集中评估了此方法,仅使用2%的Eyepacs列车标记图像,分别使用0.94和0.89 AUC。
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深度强化学习(RL)是解决复杂机器人问题的有前途的方法。但是,尽管RL算法的进步最近取得了进步,但通过反复互动进行学习的过程通常是非常耗时的。此外,RL的成功在很大程度上取决于奖励成型功能适合任务的程度,这也耗时为设计。随着对各种机器人问题培训的代理商继续扩散,重复其对新领域的宝贵学习的能力变得越来越重要。在本文中,我们提出了一种利用最佳运输理论的政策融合后的事后技术,作为合并在不同情况下训练多种代理的知识的强大手段。我们进一步证明,这为学习新任务的神经网络政策提供了改进的权重初始化,需要比重新验证父母政策或从头开始培训新政策的时间和计算资源更少。最终,我们对Deep RL中常用的不同代理商的结果表明,专业知识可以统一为“文艺复兴时期的代理人”,从而可以更快地学习新技能。
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可变形的物体操纵仍然是机器人研究中的具有挑战性的任务。用于参数推断和状态估计的传统技术通常依赖于状态空间的精确定义及其动态。虽然这适用于刚性物体和机器人状态,但定义可变形物体的状态空间并如何及时演变。在这项工作中,我们构成了作为用模拟器定义的概率推断任务的可变形对象的物理参数的问题。我们提出了一种用于通过技术从图像序列提取状态信息的新方法,以将可变形对象作为分布嵌入的状态提取。这允许以原则的方式将噪声状态观察直接进入基于现代贝叶斯模拟的推理工具。我们的实验证实,我们可以估计物理性质的后部分布,例如高可变形物体的弹性,摩擦和尺度,例如布和绳索。总的来说,我们的方法解决了概率的实际问题,并有助于更好地代表可变形对象状态的演变。
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深度学习的兴起导致机器人研究中的范式转变,有利于需要大量数据的方法。在物理平台上生成这样的数据集是昂贵的。因此,最先进的方法在模拟中学习,其中数据生成快速以及廉价并随后将知识转移到真实机器人(SIM-to-Real)。尽管变得越来越真实,但所有模拟器都是基于模型的施工,因此不可避免地不完善。这提出了如何修改模拟器以促进学习机器人控制政策的问题,并克服模拟与现实之间的不匹配,通常称为“现实差距”。我们对机器人学的SIM-Teal研究提供了全面的审查,专注于名为“域随机化”的技术,这是一种从随机仿真学习的方法。
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在操纵器需要执行多个连续任务的环境中,对象操纵的行为将改变基础配置空间,从而影响所有后续任务。以前的免费配置现在可能被操纵的对象占据,并且以前占用的空间现在可能打开新的路径。我们提出了基于懒惰的Replanner(LTR*) - 一种新型的混合计划者,旨在继承现有的任何时间增量采样计划者的快速计划性质。同时,它允许后续任务通过懒惰的体验图来利用先前的经验。以懒惰的图结构总结了先前的经验,而Ltr*的表述是强大和有益的,无论工作空间的变化程度如何。与现有的基于路线图的规划人员相比,我们的混合方法在获得初始解决方案方面的速度更快,并且轨迹长度的成本较低。随后的任务可以利用懒惰的体验图来加快找到解决方案并利用优化图来最大程度地减少成本目标。我们提供概率完整性和几乎渐近的最佳保证的证明。在实验上,我们表明,在重复的选择任务中,LTR*在计划后续任务时的性能很高。
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点云匹配中不确定性的量化在许多任务中是关键的,例如姿势估计,传感器融合和抓握。迭代最近的点(ICP)是一种常用的姿势估计算法,它提供了两个点云之间的变换的点估计。在该过程中存在许多不确定性来源,这可能由于传感器噪声,含糊不清的环境和遮挡而产生。然而,对于自主驾驶等安全性问题,对于姿势变换的点估计是不足的,因为它不提供关于多解决方案的信息。目前的概率ICP方法通常不会捕获所有不确定性的来源,并且可以提供不可靠的变换估计,这可能在状态估计或使用此信息的任务中具有不利影响。在这项工作中,我们提出了一种新的算法来对齐两个点云,可以精确估计ICP的变换参数的不确定性。我们开发了基于梯度的ICP成本函数优化的Stein变分推断框架。该方法提供了对变换的非参数估计,可以模拟复杂的多模态分布,并且可以在GPU上有效地平行化。使用3D Kinect数据以及稀疏室内/室外激光雷达数据的实验表明,我们的方法能够有效地生产准确的构成不确定性估计。
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This paper explores a pragmatic approach to multiple object tracking where the main focus is to associate objects efficiently for online and realtime applications. To this end, detection quality is identified as a key factor influencing tracking performance, where changing the detector can improve tracking by up to 18.9%. Despite only using a rudimentary combination of familiar techniques such as the Kalman Filter and Hungarian algorithm for the tracking components, this approach achieves an accuracy comparable to state-of-the-art online trackers. Furthermore, due to the simplicity of our tracking method, the tracker updates at a rate of 260 Hz which is over 20x faster than other state-of-the-art trackers.
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Recent years have seen a proliferation of research on adversarial machine learning. Numerous papers demonstrate powerful algorithmic attacks against a wide variety of machine learning (ML) models, and numerous other papers propose defenses that can withstand most attacks. However, abundant real-world evidence suggests that actual attackers use simple tactics to subvert ML-driven systems, and as a result security practitioners have not prioritized adversarial ML defenses. Motivated by the apparent gap between researchers and practitioners, this position paper aims to bridge the two domains. We first present three real-world case studies from which we can glean practical insights unknown or neglected in research. Next we analyze all adversarial ML papers recently published in top security conferences, highlighting positive trends and blind spots. Finally, we state positions on precise and cost-driven threat modeling, collaboration between industry and academia, and reproducible research. We believe that our positions, if adopted, will increase the real-world impact of future endeavours in adversarial ML, bringing both researchers and practitioners closer to their shared goal of improving the security of ML systems.
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When simulating soft robots, both their morphology and their controllers play important roles in task performance. This paper introduces a new method to co-evolve these two components in the same process. We do that by using the hyperNEAT algorithm to generate two separate neural networks in one pass, one responsible for the design of the robot body structure and the other for the control of the robot. The key difference between our method and most existing approaches is that it does not treat the development of the morphology and the controller as separate processes. Similar to nature, our method derives both the "brain" and the "body" of an agent from a single genome and develops them together. While our approach is more realistic and doesn't require an arbitrary separation of processes during evolution, it also makes the problem more complex because the search space for this single genome becomes larger and any mutation to the genome affects "brain" and the "body" at the same time. Additionally, we present a new speciation function that takes into consideration both the genotypic distance, as is the standard for NEAT, and the similarity between robot bodies. By using this function, agents with very different bodies are more likely to be in different species, this allows robots with different morphologies to have more specialized controllers since they won't crossover with other robots that are too different from them. We evaluate the presented methods on four tasks and observe that even if the search space was larger, having a single genome makes the evolution process converge faster when compared to having separated genomes for body and control. The agents in our population also show morphologies with a high degree of regularity and controllers capable of coordinating the voxels to produce the necessary movements.
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