Modeling perception sensors is key for simulation based testing of automated driving functions. Beyond weather conditions themselves, sensors are also subjected to object dependent environmental influences like tire spray caused by vehicles moving on wet pavement. In this work, a novel modeling approach for spray in lidar data is introduced. The model conforms to the Open Simulation Interface (OSI) standard and is based on the formation of detection clusters within a spray plume. The detections are rendered with a simple custom ray casting algorithm without the need of a fluid dynamics simulation or physics engine. The model is subsequently used to generate training data for object detection algorithms. It is shown that the model helps to improve detection in real-world spray scenarios significantly. Furthermore, a systematic real-world data set is recorded and published for analysis, model calibration and validation of spray effects in active perception sensors. Experiments are conducted on a test track by driving over artificially watered pavement with varying vehicle speeds, vehicle types and levels of pavement wetness. All models and data of this work are available open source.
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Profile extrusion is a continuous production process for manufacturing plastic profiles from molten polymer. Especially interesting is the design of the die, through which the melt is pressed to attain the desired shape. However, due to an inhomogeneous velocity distribution at the die exit or residual stresses inside the extrudate, the final shape of the manufactured part often deviates from the desired one. To avoid these deviations, the shape of the die can be computationally optimized, which has already been investigated in the literature using classical optimization approaches. A new approach in the field of shape optimization is the utilization of Reinforcement Learning (RL) as a learning-based optimization algorithm. RL is based on trial-and-error interactions of an agent with an environment. For each action, the agent is rewarded and informed about the subsequent state of the environment. While not necessarily superior to classical, e.g., gradient-based or evolutionary, optimization algorithms for one single problem, RL techniques are expected to perform especially well when similar optimization tasks are repeated since the agent learns a more general strategy for generating optimal shapes instead of concentrating on just one single problem. In this work, we investigate this approach by applying it to two 2D test cases. The flow-channel geometry can be modified by the RL agent using so-called Free-Form Deformation, a method where the computational mesh is embedded into a transformation spline, which is then manipulated based on the control-point positions. In particular, we investigate the impact of utilizing different agents on the training progress and the potential of wall time saving by utilizing multiple environments during training.
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We present a novel clustering algorithm, visClust, that is based on lower dimensional data representations and visual interpretation. Thereto, we design a transformation that allows the data to be represented by a binary integer array enabling the further use of image processing methods to select a partition. Qualitative and quantitative analyses show that the algorithm obtains high accuracy (measured with an adjusted one-sided Rand-Index) and requires low runtime and RAM. We compare the results to 6 state-of-the-art algorithms, confirming the quality of visClust by outperforming in most experiments. Moreover, the algorithm asks for just one obligatory input parameter while allowing optimization via optional parameters. The code is made available on GitHub.
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我们提出了一种新的抽样策略,称为Smart Active Sapling,以在生产线之外进行质量检查。根据主动学习的原则,机器学习模型决定将哪些样品发送到质量检查。一方面,由于较早发现质量违规行为,这可以最大程度地减少废料零件的产生。另一方面,质量检查成本降低了,以进行平稳运行。
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本文介绍了一种用于检测变更点的算法,并鉴定了瞬态多元时间序列数据(MTSD)中相应的子序列。由于许多工业领域的可用性增加,对此类数据的分析变得越来越重要。用于基于训练条件的维护(CBM)模型的标签,排序或过滤高度瞬态测量数据很麻烦且容易出错。对于某些应用程序,可以通过简单阈值或基于平均值和变化的变化找到更改点来过滤测量值。但是,例如,组件组中组件的强大诊断,该组件在多个传感器值之间具有复杂的非线性相关性,简单的方法是不可行的。可以将CBM模型出现的有意义且相干的测量数据。因此,我们介绍了一种使用基于复发的神经网络(RNN)自动编码器(AE)的算法,该算法对传入数据进行了迭代训练。评分函数使用重建误差和潜在空间信息。保存了确定的子序列的模型,并用于识别重复子序列以及快速离线聚类。为了进行评估,我们提出了一种基于曲率的新相似性度量,以实现更直观的时间序列子序列聚类指标。与其他七种最先进的算法和八个数据集进行了比较,显示了我们算法对在线群集MTSD和与机电系统结合的群集MTSD的功能和性能的提高。
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财产数据的可用性是化学过程开发中的主要瓶颈之一,通常需要耗时且昂贵的实验或将设计空间限制为少数已知分子。这种瓶颈一直是预测性财产模型持续发展的动机。对于新分子的性质预测,群体贡献方法一直在开创性。最近,机器学习加入了更具成熟的财产预测模型。但是,即使取得了最近的成功,将物理约束集成到机器学习模型中仍然具有挑战性。物理约束对于许多热力学特性,例如吉布斯 - 杜纳姆(Gibbs-Dunham)关系至关重要,它将额外的复杂性层引入预测中。在这里,我们介绍了SPT-NRTL,这是一种机器学习模型,以预测热力学一致的活动系数并提供NRTL参数,以便于过程模拟。结果表明,SPT-NRTL在所有官能团的活性系数预测中的精度高于UNIFAC,并且能够以几乎实验的精度预测许多蒸气 - 液位均衡性,如示例性混合物所示。 N-己烷。为了简化SPT-NRTL的应用,用SPT-NRTL计算了100 000 000的NRTL参数,并在线提供。
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我们研究了精神病学临床领域中脑唤醒的调节改变了面部行为的统计特性。潜在的机制与对某些心理状态的行为替代测量的警惕性连续体的经验解释有关。我们以基于经典的头皮的审视传感器(OEG)的意义命名了所提出的测量,该传感器光电脑摄影(OEG)仅依赖于现代基于摄像机的实时信号处理和计算机视觉。基于随机表示作为面部动力学的连贯性,反映了情绪表达中的半径不对称性,我们证明了患者与健康对照之间几乎没有完美的区别,以及精神疾病抑郁症和精神分裂症和症状的严重性。与标准诊断过程相反,该过程耗时,主观,不包含神经生物学数据,例如实时面部动力学,情感响应能力的客观随机建模仅需要几分钟的基于视频的面部录制。我们还强调了该方法作为因果推断模型在转诊分析中的潜力,以预测药理治疗的结果。所有结果均在临床纵向数据收集中获得,其中有100名患者和50例对照。
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安全政策改进(SPI)是在安全关键应用中脱机加强学习的重要技术,因为它以很高的可能性改善了行为政策。我们根据如何利用国家行动对的不确定性将各种SPI方法分为两组。为了关注软SPIBB(通过软基线自举的安全政策改进)算法,我们表明他们对被证明安全的主张不坚持。基于这一发现,我们开发了适应性,Adv-Soft SpibB算法,并证明它们是可以安全的。在两个基准上进行的广泛实验中,启发式适应性较低的SPOBB在所有SPIBB算法中都能表现出最佳性能。我们还检查了可证明的安全算法的安全保证,并表明有大量数据是必要的,以使安全界限在实践中变得有用。
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越来越复杂的威胁参与者以及网络攻击不断发展的巨大速度,及时确定对组织的安全必须识别攻击。因此,负责安全的人采用了有关新兴攻击,攻击者的行动或妥协指标的各种信息来源。但是,大量所需的安全信息以非结构化的文本形式获得,这使攻击者策略,技术和程序(TTPS)的自动化和及时提取变得复杂。为了解决这个问题,我们系统地评估和比较了用于安全信息提取的不同自然语言处理(NLP)和机器学习技术。根据我们的调查,我们提出了一条数据处理管道,该管道会根据攻击者的策略和技术自动对非结构化文本进行分类,这些策略和技术从对手策略,技术和程序的知识库中得出。
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抓握是通过在一组触点上施加力和扭矩来挑选对象的过程。深度学习方法的最新进展允许在机器人对象抓地力方面快速进步。我们在过去十年中系统地调查了出版物,特别感兴趣使用最终效果姿势的所有6度自由度抓住对象。我们的综述发现了四种用于机器人抓钩的常见方法:基于抽样的方法,直接回归,强化学习和示例方法。此外,我们发现了围绕抓握的两种“支持方法”,这些方法使用深入学习来支持抓握过程,形状近似和负担能力。我们已经将本系统评论(85篇论文)中发现的出版物提炼为十个关键要点,我们认为对未来的机器人抓握和操纵研究至关重要。该调查的在线版本可从https://rhys-newbury.github.io/projects/6dof/获得
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