在本文中,我们在使用离散的Langevin扩散的三个方案中从目标密度采样的误差提供非渐近上限。第一个方案是Langevin Monte Carlo(LMC)算法,歌曲的欧拉分散化的歌曲扩散。第二个和第三种方案分别是用于可微分电位和动力学Langevin Monte Carlo的动力学Langevin Monte Carlo(KLMC),用于两次可分视电位(KLMC2)。主要焦点是在$ \ mathbb r ^ p $的目标密度上,但不一定强烈地抖动。在两种类型的平滑假设下获得计算复杂度的界限:电位具有嘴唇连续梯度,并且电位具有嘴角连续的Hessian基质。采样误差由Wassersein-$ Q $距离测量。我们倡导在计算复杂性定义中使用新的维度适应缩放,当考虑Wasserstein-$ Q $距离时。所获得的结果表明,实现小于规定值的缩放误差的迭代次数仅取决于多项尺寸。
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Reduced order modeling methods are often used as a mean to reduce simulation costs in industrial applications. Despite their computational advantages, reduced order models (ROMs) often fail to accurately reproduce complex dynamics encountered in real life applications. To address this challenge, we leverage NeuralODEs to propose a novel ROM correction approach based on a time-continuous memory formulation. Finally, experimental results show that our proposed method provides a high level of accuracy while retaining the low computational costs inherent to reduced models.
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Recent advances in deep learning (dl) have led to the release of several dl software libraries such as pytorch, Caffe, and TensorFlow, in order to assist machine learning (ml) practitioners in developing and deploying state-of-the-art deep neural networks (DNN), but they are not able to properly cope with limitations in the dl libraries such as testing or data processing. In this paper, we present a qualitative and quantitative analysis of the most frequent dl libraries combination, the distribution of dl library dependencies across the ml workflow, and formulate a set of recommendations to (i) hardware builders for more optimized accelerators and (ii) library builder for more refined future releases. Our study is based on 1,484 open-source dl projects with 46,110 contributors selected based on their reputation. First, we found an increasing trend in the usage of deep learning libraries. Second, we highlight several usage patterns of deep learning libraries. In addition, we identify dependencies between dl libraries and the most frequent combination where we discover that pytorch and Scikit-learn and, Keras and TensorFlow are the most frequent combination in 18% and 14% of the projects. The developer uses two or three dl libraries in the same projects and tends to use different multiple dl libraries in both the same function and the same files. The developer shows patterns in using various deep-learning libraries and prefers simple functions with fewer arguments and straightforward goals. Finally, we present the implications of our findings for researchers, library maintainers, and hardware vendors.
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Increasingly, malwares are becoming complex and they are spreading on networks targeting different infrastructures and personal-end devices to collect, modify, and destroy victim information. Malware behaviors are polymorphic, metamorphic, persistent, able to hide to bypass detectors and adapt to new environments, and even leverage machine learning techniques to better damage targets. Thus, it makes them difficult to analyze and detect with traditional endpoint detection and response, intrusion detection and prevention systems. To defend against malwares, recent work has proposed different techniques based on signatures and machine learning. In this paper, we propose to use an algebraic topological approach called topological-based data analysis (TDA) to efficiently analyze and detect complex malware patterns. Next, we compare the different TDA techniques (i.e., persistence homology, tomato, TDA Mapper) and existing techniques (i.e., PCA, UMAP, t-SNE) using different classifiers including random forest, decision tree, xgboost, and lightgbm. We also propose some recommendations to deploy the best-identified models for malware detection at scale. Results show that TDA Mapper (combined with PCA) is better for clustering and for identifying hidden relationships between malware clusters compared to PCA. Persistent diagrams are better to identify overlapping malware clusters with low execution time compared to UMAP and t-SNE. For malware detection, malware analysts can use Random Forest and Decision Tree with t-SNE and Persistent Diagram to achieve better performance and robustness on noised data.
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Deep Neural Networks (DNNs) have been widely used to perform real-world tasks in cyber-physical systems such as Autonomous Driving Systems (ADS). Ensuring the correct behavior of such DNN-Enabled Systems (DES) is a crucial topic. Online testing is one of the promising modes for testing such systems with their application environments (simulated or real) in a closed loop taking into account the continuous interaction between the systems and their environments. However, the environmental variables (e.g., lighting conditions) that might change during the systems' operation in the real world, causing the DES to violate requirements (safety, functional), are often kept constant during the execution of an online test scenario due to the two major challenges: (1) the space of all possible scenarios to explore would become even larger if they changed and (2) there are typically many requirements to test simultaneously. In this paper, we present MORLOT (Many-Objective Reinforcement Learning for Online Testing), a novel online testing approach to address these challenges by combining Reinforcement Learning (RL) and many-objective search. MORLOT leverages RL to incrementally generate sequences of environmental changes while relying on many-objective search to determine the changes so that they are more likely to achieve any of the uncovered objectives. We empirically evaluate MORLOT using CARLA, a high-fidelity simulator widely used for autonomous driving research, integrated with Transfuser, a DNN-enabled ADS for end-to-end driving. The evaluation results show that MORLOT is significantly more effective and efficient than alternatives with a large effect size. In other words, MORLOT is a good option to test DES with dynamically changing environments while accounting for multiple safety requirements.
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最近已经提出了方法,仅使用稀疏语义注释像素的形式使用颜色图像和专家监督,将密度段3D卷成类。尽管令人印象深刻,但这些方法仍然需要相对较大的监督和对象进行分割可能需要几分钟的实践。这样的系统通常仅在其拟合的特定场景上优化其表示形式,而无需利用先前看到的图像中的任何先前信息。在本文中,我们建议使用在大型现有数据集中训练的模型提取的功能,以提高细分性能。我们通过体积渲染特征图和从每个输入图像提取的特征进行监督,将此特征表示形式烘烤到神经辐射场(NERF)中。我们表明,通过将此表示形式烘烤到NERF中,我们可以使后续的分类任务更加容易。我们的实验表明,与在各种场景中现有方法相比,我们的方法具有更高的分割精度,语义注释较少。
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对于移动机器人而言,与铰接式对象的交互是一项具有挑战性但重要的任务。为了应对这一挑战,我们提出了一条新型的闭环控制管道,该管道将负担能力估计的操纵先验与基于采样的全身控制相结合。我们介绍了完全反映了代理的能力和体现的代理意识提供的概念,我们表明它们的表现优于其最先进的对应物,这些对应物仅以最终效果的几何形状为条件。此外,发现闭环负担推论使代理可以将任务分为多个非连续运动,并从失败和意外状态中恢复。最后,管道能够执行长途移动操作任务,即在现实世界中开放和关闭烤箱,成功率很高(开放:71%,关闭:72%)。
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大气污染仍然是全球主要的公共卫生威胁之一,估计每年7万人死亡。在非洲,快速的城市化和运输基础设施不良正在加剧问题。在本文中,我们分析了非洲不同地理区域的PM2.5的时空变化。西非地区仍然受到高水平污染的影响最大,每天平均40.856 $ \ mu g/m^3 $在拉各斯,阿布贾和巴马科等某些城市。在东非,乌干达报告的污染水平最高,每日平均浓度为56.14 $ \ mu g/m^3 $和38.65 $ \ mu g/m^3 $,用于基加利。在非洲中部地区的国家/地区,每日最高的平均浓度为90.075 $ \ mu g/m^3 $,记录在N'djamena中。我们比较了三个数据驱动模型,以预测污染水平的未来趋势。神经网络的表现优于高斯过程和Arima模型。
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从混乱中挑选特定对象是许多操纵任务的重要组成部分。部分观察结果通常要求机器人在尝试掌握之前收集场景的其他观点。本文提出了一个闭环的下一次最佳策划者,该计划者根据遮挡的对象零件驱动探索。通过不断从最新场景重建中预测抓地力,我们的政策可以在线决定最终确定执行或适应机器人的轨迹以进行进一步探索。我们表明,与常见的相机位置和处理固定基线失败的情况相比,我们的反应性方法会减少执行时间而不会丢失掌握成功率。视频和代码可在https://github.com/ethz-asl/active_grasp上找到。
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本文介绍了Cerberus机器人系统系统,该系统赢得了DARPA Subterranean挑战最终活动。出席机器人自主权。由于其几何复杂性,降解的感知条件以及缺乏GPS支持,严峻的导航条件和拒绝通信,地下设置使自动操作变得特别要求。为了应对这一挑战,我们开发了Cerberus系统,该系统利用了腿部和飞行机器人的协同作用,再加上可靠的控制,尤其是为了克服危险的地形,多模式和多机器人感知,以在传感器退化,以及在传感器退化的条件下进行映射以及映射通过统一的探索路径计划和本地运动计划,反映机器人特定限制的弹性自主权。 Cerberus基于其探索各种地下环境及其高级指挥和控制的能力,表现出有效的探索,对感兴趣的对象的可靠检测以及准确的映射。在本文中,我们报告了DARPA地下挑战赛的初步奔跑和最终奖项的结果,并讨论了为社区带来利益的教训所面临的亮点和挑战。
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