One of today's goals for industrial robot systems is to allow fast and easy provisioning for new tasks. Skill-based systems that use planning and knowledge representation have long been one possible answer to this. However, especially with contact-rich robot tasks that need careful parameter settings, such reasoning techniques can fall short if the required knowledge not adequately modeled. We show an approach that provides a combination of task-level planning and reasoning with targeted learning of skill parameters for a task at hand. Starting from a task goal formulated in PDDL, the learnable parameters in the plan are identified and an operator can choose reward functions and parameters for the learning process. A tight integration with a knowledge framework allows to form a prior for learning and the usage of multi-objective Bayesian optimization eases to balance aspects such as safety and task performance that can often affect each other. We demonstrate the efficacy and versatility of our approach by learning skill parameters for two different contact-rich tasks and show their successful execution on a real 7-DOF KUKA-iiwa.
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网络物理系统(CPSS)通常是复杂且至关重要的;因此,确保系统的要求,即规格,很难满足。基于仿真的CPS伪造是一种实用的测试方法,可用于通过仅要求模拟正在测试的系统来提高对系统正确性的信心。由于每个仿真通常在计算上进行密集,因此一个重要的步骤是减少伪造规范所需的仿真数量。我们研究贝叶斯优化(BO),一种样本效率的方法,它学习了一个替代模型,该模型描述了可能的输入信号的参数化与规范评估之间的关系。在本文中,我们改善了使用BO的伪造;首先采用两种突出的BO方法,一种适合本地替代模型,另一个适合当地的替代模型,利用了用户的先验知识。其次,本文介绍了伪造功能的采集函数的表述。基准评估显示,使用BO的局部替代模型来伪造以前难以伪造的基准示例的显着改善。在伪造过程中使用先验知识被证明是在模拟预算有限时特别重要的。对于某些基准问题,采集功能的选择清楚地影响了成功伪造所需的模拟数量。
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机器人技能系统旨在减少机器人设置时间的新制造任务。但是,对于灵巧,接触术的任务,通常很难找到正确的技能参数。一种策略是通过允许机器人系统直接学习任务来学习这些参数。对于学习问题,机器人操作员通常可以指定参数值的类型和范围。然而,鉴于他们先前的经验,机器人操作员应该能够通过提供有关在参数空间中找到最佳解决方案的知识猜测,从而进一步帮助学习过程。有趣的是,当前的机器人学习框架中没有利用这种先验知识。我们介绍了一种结合用户先验和贝叶斯优化的方法,以便在机器人部署时间快速优化机器人工业任务。我们在模拟中学习的三个任务以及直接在真实机器人系统上学习的两个任务中学习了我们的方法。此外,我们通过自动从良好表现的配置中自动构造先验来从相应的仿真任务中转移知识,以在真实系统上学习。为了处理潜在的任务目标,任务被建模为多目标问题。我们的结果表明,操作员的先验是用户指定和转移的,大大加快了富丽堂皇的阵线的发现,并且通常产生的最终性能远远超过了拟议的基线。
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信息理论的贝叶斯优化技术因其非洋流品质而变得越来越流行,以优化昂贵的黑盒功能。熵搜索和预测性熵搜索都考虑了输入空间中最佳的熵,而最新的最大值熵搜索则考虑了输出空间中最佳值的熵。我们提出了联合熵搜索(JES),这是一种新的信息理论采集函数,它考虑了全新的数量,即输入和输出空间上关节最佳概率密度的熵。为了结合此信息,我们考虑从幻想的最佳输入/输出对条件下的熵减少。最终的方法主要依赖于标准的GP机械,并去除通常与信息理论方法相关的复杂近似值。凭借最少的计算开销,JES展示了卓越的决策,并在各种任务中提供了信息理论方法的最新性能。作为具有出色结果的轻重量方法,JES为贝叶斯优化提供了新的首选功能。
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尽管加权套索回归具有吸引力的统计保障,但由于其复杂的搜索空间,通常避免了已有数千个Quand参与的。另一方面,具有用于黑盒功能的高维HPO方法的最新进展表明,高维应用确实可以有效地优化。尽管这一初步成功,但高维HPO方法通常应用于具有适度数量的合成问题,这些尺寸限制了其对科学和工程应用的影响。为了解决这一限制,我们提出了一个新的基准套件,这是一个在卢赛社区中的一个重要的开放研究主题量身定制的,这是加权套索回归。 Lassobench由受良好控制的合成设置(样本,SNR,环境和有效维度以及多维保真度)和现实世界数据集组成的基准,这使得能够利用许多HPO算法来改进和扩展到高维设置。我们评估了5种最先进的HPO方法和3个基线,并表明贝叶斯优化可以改善通常用于稀疏回归的方法,同时突出显示这些框架在非常高的框架中的限制。值得注意的是,贝叶斯优化分别将60,100,300和1000个尺寸问题的卢斯基线分别改善了45.7%,19.2%,19.7%和15.5%。
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增强学习(RL)是一个强大的数学框架,可让机器人通过反复试验学习复杂的技能。尽管在许多应用中取得了许多成功,但RL算法仍然需要数千个试验才能融合到高性能的政策,可以在学习时产生危险的行为,并且优化的政策(通常为神经网络建模)几乎可以在无法执行的解释时给出零的解释。任务。由于这些原因,在工业环境中采用RL并不常见。另一方面,行为树(BTS)可以提供一个策略表示,a)支持模块化和可综合的技能,b)允许轻松解释机器人动作,c)提供了有利的低维参数空间。在本文中,我们提出了一种新颖的算法,该算法可以学习模拟中BT策略的参数,然后在没有任何其他培训的情况下将其推广到物理机器人。我们利用了使用数字化工作站的物理模拟器,并使用黑盒优化器优化相关参数。我们在包括避免障碍物和富含接触的插入(孔洞)的任务中,通过7道型kuka-iiwa操纵器展示了我们方法的功效,其中我们的方法优于基准。
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We present a Machine Learning (ML) study case to illustrate the challenges of clinical translation for a real-time AI-empowered echocardiography system with data of ICU patients in LMICs. Such ML case study includes data preparation, curation and labelling from 2D Ultrasound videos of 31 ICU patients in LMICs and model selection, validation and deployment of three thinner neural networks to classify apical four-chamber view. Results of the ML heuristics showed the promising implementation, validation and application of thinner networks to classify 4CV with limited datasets. We conclude this work mentioning the need for (a) datasets to improve diversity of demographics, diseases, and (b) the need of further investigations of thinner models to be run and implemented in low-cost hardware to be clinically translated in the ICU in LMICs. The code and other resources to reproduce this work are available at https://github.com/vital-ultrasound/ai-assisted-echocardiography-for-low-resource-countries.
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Early on during a pandemic, vaccine availability is limited, requiring prioritisation of different population groups. Evaluating vaccine allocation is therefore a crucial element of pandemics response. In the present work, we develop a model to retrospectively evaluate age-dependent counterfactual vaccine allocation strategies against the COVID-19 pandemic. To estimate the effect of allocation on the expected severe-case incidence, we employ a simulation-assisted causal modelling approach which combines a compartmental infection-dynamics simulation, a coarse-grained, data-driven causal model and literature estimates for immunity waning. We compare Israel's implemented vaccine allocation strategy in 2021 to counterfactual strategies such as no prioritisation, prioritisation of younger age groups or a strict risk-ranked approach; we find that Israel's implemented strategy was indeed highly effective. We also study the marginal impact of increasing vaccine uptake for a given age group and find that increasing vaccinations in the elderly is most effective at preventing severe cases, whereas additional vaccinations for middle-aged groups reduce infections most effectively. Due to its modular structure, our model can easily be adapted to study future pandemics. We demonstrate this flexibility by investigating vaccine allocation strategies for a pandemic with characteristics of the Spanish Flu. Our approach thus helps evaluate vaccination strategies under the complex interplay of core epidemic factors, including age-dependent risk profiles, immunity waning, vaccine availability and spreading rates.
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Objective: Thigh muscle group segmentation is important for assessment of muscle anatomy, metabolic disease and aging. Many efforts have been put into quantifying muscle tissues with magnetic resonance (MR) imaging including manual annotation of individual muscles. However, leveraging publicly available annotations in MR images to achieve muscle group segmentation on single slice computed tomography (CT) thigh images is challenging. Method: We propose an unsupervised domain adaptation pipeline with self-training to transfer labels from 3D MR to single CT slice. First, we transform the image appearance from MR to CT with CycleGAN and feed the synthesized CT images to a segmenter simultaneously. Single CT slices are divided into hard and easy cohorts based on the entropy of pseudo labels inferenced by the segmenter. After refining easy cohort pseudo labels based on anatomical assumption, self-training with easy and hard splits is applied to fine tune the segmenter. Results: On 152 withheld single CT thigh images, the proposed pipeline achieved a mean Dice of 0.888(0.041) across all muscle groups including sartorius, hamstrings, quadriceps femoris and gracilis. muscles Conclusion: To our best knowledge, this is the first pipeline to achieve thigh imaging domain adaptation from MR to CT. The proposed pipeline is effective and robust in extracting muscle groups on 2D single slice CT thigh images.The container is available for public use at https://github.com/MASILab/DA_CT_muscle_seg
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In this paper, we propose the first-ever real benchmark thought for evaluating Neural Radiance Fields (NeRFs) and, in general, Neural Rendering (NR) frameworks. We design and implement an effective pipeline for scanning real objects in quantity and effortlessly. Our scan station is built with less than 500$ hardware budget and can collect roughly 4000 images of a scanned object in just 5 minutes. Such a platform is used to build ScanNeRF, a dataset characterized by several train/val/test splits aimed at benchmarking the performance of modern NeRF methods under different conditions. Accordingly, we evaluate three cutting-edge NeRF variants on it to highlight their strengths and weaknesses. The dataset is available on our project page, together with an online benchmark to foster the development of better and better NeRFs.
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