我们提出了一种架构,其中导致环境近似模型导出的反馈控制器有助于学习过程来提高其数据效率。我们作为控制辅导Q-Learning(CTQL)的这个架构,在两个替代的口味中呈现。前者是基于定义奖励功能,以便可以使用布尔条件来确定采用控制导师策略,而后者被称为概率CTQL(PCTQL),则是基于与Tutor的执行呼叫学习期间的某些概率。通过考虑在Openai Body中定义的倒挂摆在作为代表性问题,通过验证两种方法,并彻底地反对Q-Learning基准测试。
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Shape displays are a class of haptic devices that enable whole-hand haptic exploration of 3D surfaces. However, their scalability is limited by the mechanical complexity and high cost of traditional actuator arrays. In this paper, we propose using electroadhesive auxetic skins as a strain-limiting layer to create programmable shape change in a continuous ("formable crust") shape display. Auxetic skins are manufactured as flexible printed circuit boards with dielectric-laminated electrodes on each auxetic unit cell (AUC), using monolithic fabrication to lower cost and assembly time. By layering multiple sheets and applying a voltage between electrodes on subsequent layers, electroadhesion locks individual AUCs, achieving a maximum in-plane stiffness variation of 7.6x with a power consumption of 50 uW/AUC. We first characterize an individual AUC and compare results to a kinematic model. We then validate the ability of a 5x5 AUC array to actively modify its own axial and transverse stiffness. Finally, we demonstrate this array in a continuous shape display as a strain-limiting skin to programmatically modulate the shape output of an inflatable LDPE pouch. Integrating electroadhesion with auxetics enables new capabilities for scalable, low-profile, and low-power control of flexible robotic systems.
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This paper proposes a novel Adaptive Clustering-based Reduced-Order Modeling (ACROM) framework to significantly improve and extend the recent family of clustering-based reduced-order models (CROMs). This adaptive framework enables the clustering-based domain decomposition to evolve dynamically throughout the problem solution, ensuring optimum refinement in regions where the relevant fields present steeper gradients. It offers a new route to fast and accurate material modeling of history-dependent nonlinear problems involving highly localized plasticity and damage phenomena. The overall approach is composed of three main building blocks: target clusters selection criterion, adaptive cluster analysis, and computation of cluster interaction tensors. In addition, an adaptive clustering solution rewinding procedure and a dynamic adaptivity split factor strategy are suggested to further enhance the adaptive process. The coined Adaptive Self-Consistent Clustering Analysis (ASCA) is shown to perform better than its static counterpart when capturing the multi-scale elasto-plastic behavior of a particle-matrix composite and predicting the associated fracture and toughness. Given the encouraging results shown in this paper, the ACROM framework sets the stage and opens new avenues to explore adaptivity in the context of CROMs.
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The number of international benchmarking competitions is steadily increasing in various fields of machine learning (ML) research and practice. So far, however, little is known about the common practice as well as bottlenecks faced by the community in tackling the research questions posed. To shed light on the status quo of algorithm development in the specific field of biomedical imaging analysis, we designed an international survey that was issued to all participants of challenges conducted in conjunction with the IEEE ISBI 2021 and MICCAI 2021 conferences (80 competitions in total). The survey covered participants' expertise and working environments, their chosen strategies, as well as algorithm characteristics. A median of 72% challenge participants took part in the survey. According to our results, knowledge exchange was the primary incentive (70%) for participation, while the reception of prize money played only a minor role (16%). While a median of 80 working hours was spent on method development, a large portion of participants stated that they did not have enough time for method development (32%). 25% perceived the infrastructure to be a bottleneck. Overall, 94% of all solutions were deep learning-based. Of these, 84% were based on standard architectures. 43% of the respondents reported that the data samples (e.g., images) were too large to be processed at once. This was most commonly addressed by patch-based training (69%), downsampling (37%), and solving 3D analysis tasks as a series of 2D tasks. K-fold cross-validation on the training set was performed by only 37% of the participants and only 50% of the participants performed ensembling based on multiple identical models (61%) or heterogeneous models (39%). 48% of the respondents applied postprocessing steps.
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One of the major challenges in Deep Reinforcement Learning for control is the need for extensive training to learn the policy. Motivated by this, we present the design of the Control-Tutored Deep Q-Networks (CT-DQN) algorithm, a Deep Reinforcement Learning algorithm that leverages a control tutor, i.e., an exogenous control law, to reduce learning time. The tutor can be designed using an approximate model of the system, without any assumption about the knowledge of the system's dynamics. There is no expectation that it will be able to achieve the control objective if used stand-alone. During learning, the tutor occasionally suggests an action, thus partially guiding exploration. We validate our approach on three scenarios from OpenAI Gym: the inverted pendulum, lunar lander, and car racing. We demonstrate that CT-DQN is able to achieve better or equivalent data efficiency with respect to the classic function approximation solutions.
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队列研究越来越多地使用加速度计进行体育活动和久坐行为估计。这些设备往往比自我报告易于错误,可以全天捕获活动,并且是经济的。但是,在自由生活的情况下和受试者对象变化下,基于髋关节wor的数据估算久坐行为的先前方法通常是无效的或次优的。在本文中,我们提出了一个本地马尔可夫切换模型,该模型考虑了这种情况,并引入了一种姿势分类和久坐行为分析的一般程序,该程序自然适合该模型。我们的方法在时间序列中具有更改点检测方法,也是一个两个阶段分类步骤,将数据标记为3类(坐着,站立,步进)。通过严格的训练测试范例,我们表明我们的方法达到了80%的精度。此外,我们的方法是强大的,易于解释。
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最小化能量的动力系统在几何和物理学中无处不在。我们为GNN提出了一个梯度流框架,其中方程遵循可学习能量的最陡峭下降的方向。这种方法允许从多粒子的角度来解释GNN的演变,以通过对称“通道混合”矩阵的正和负特征值在特征空间中学习吸引力和排斥力。我们对溶液进行光谱分析,并得出结论,梯度流量图卷积模型可以诱导以图高频为主导的动力学,这对于异性数据集是理想的。我们还描述了对常见GNN体系结构的结构约束,从而将其解释为梯度流。我们进行了彻底的消融研究,以证实我们的理论分析,并在现实世界同质和异性数据集上显示了简单和轻量级模型的竞争性能。
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在建立工程基础设施的预测模型时,提出了人群级分析来解决数据稀疏性。利用可解释的层次贝叶斯方法和操作车队数据,域专业知识是自然编码(并适当共享)在不同的子组之间,代表(i)使用型,(ii)组件或(iii)操作条件。具体而言,利用领域专业知识来通过假设(和先前的分布)来限制模型,从而使该方法可以自动共享相似资产之间的信息,从而改善了对风电场中卡车机队和权力预测的生存分析。在每个资产管理示例中,在合并的推理中学习了一组相关的功能,以学习人口模型。当允许子型在层次结构中的不同级别共享相关信息时,参数估计得到改善。反过来,数据不完整的组会自动从数据丰富的组中借用统计强度。统计相关性使知识转移能够通过贝叶斯转移学习,并且可以检查相关性,以告知哪些资产共享有关哪些效果(即参数)的信息。两种案例研究的成功都证明了实践基础设施监测的广泛适用性,因为该方法自然适应了不同原位示例的可解释的车队模型。
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数据增强是自然语言处理(NLP)模型的鲁棒性评估的重要组成部分,以及增强他们培训的数据的多样性。在本文中,我们呈现NL-Cogmenter,这是一种新的参与式Python的自然语言增强框架,它支持创建两个转换(对数据的修改)和过滤器(根据特定功能的数据拆分)。我们描述了框架和初始的117个变换和23个过滤器,用于各种自然语言任务。我们通过使用其几个转换来分析流行自然语言模型的鲁棒性来证明NL-Upmenter的功效。基础架构,Datacards和稳健性分析结果在NL-Augmenter存储库上公开可用(\ url {https://github.com/gem-benchmark/nl-augmenter})。
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大多数图形神经网络(GNNS)使用传递范例的消息,其中节点特征在输入图上传播。最近的作品指出,从远处节点流动的信息失真,作为限制依赖于长途交互的任务的消息的效率。这种现象称为“过度挤压”,已经启动到图形瓶颈,其中$ k $ -hop邻居的数量以$ k $迅速增长。我们在GNNS中提供了精确描述了GNNS中的过度挤压现象,并分析了它如何从图中的瓶颈引发。为此目的,我们介绍了一种新的基于边缘的组合曲率,并证明了负曲面负责过度挤压问题。我们还提出并通过实验测试了一种基于曲率的曲线图重新挖掘方法,以减轻过度挤压。
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