We address the theoretical and practical problems related to the trajectory generation and tracking control of tail-sitter UAVs. Theoretically, we focus on the differential flatness property with full exploitation of actual UAV aerodynamic models, which lays a foundation for generating dynamically feasible trajectory and achieving high-performance tracking control. We have found that a tail-sitter is differentially flat with accurate aerodynamic models within the entire flight envelope, by specifying coordinate flight condition and choosing the vehicle position as the flat output. This fundamental property allows us to fully exploit the high-fidelity aerodynamic models in the trajectory planning and tracking control to achieve accurate tail-sitter flights. Particularly, an optimization-based trajectory planner for tail-sitters is proposed to design high-quality, smooth trajectories with consideration of kinodynamic constraints, singularity-free constraints and actuator saturation. The planned trajectory of flat output is transformed to state trajectory in real-time with consideration of wind in environments. To track the state trajectory, a global, singularity-free, and minimally-parameterized on-manifold MPC is developed, which fully leverages the accurate aerodynamic model to achieve high-accuracy trajectory tracking within the whole flight envelope. The effectiveness of the proposed framework is demonstrated through extensive real-world experiments in both indoor and outdoor field tests, including agile SE(3) flight through consecutive narrow windows requiring specific attitude and with speed up to 10m/s, typical tail-sitter maneuvers (transition, level flight and loiter) with speed up to 20m/s, and extremely aggressive aerobatic maneuvers (Wingover, Loop, Vertical Eight and Cuban Eight) with acceleration up to 2.5g.
translated by 谷歌翻译
Knowledge distillation is often used to transfer knowledge from a strong teacher model to a relatively weak student model. Traditional knowledge distillation methods include response-based methods and feature-based methods. Response-based methods are used the most widely but suffer from lower upper limit of model performance, while feature-based methods have constraints on the vocabularies and tokenizers. In this paper, we propose a tokenizer-free method liberal feature-based distillation (LEAD). LEAD aligns the distribution between teacher model and student model, which is effective, extendable, portable and has no requirements on vocabularies, tokenizer, or model architecture. Extensive experiments show the effectiveness of LEAD on several widely-used benchmarks, including MS MARCO Passage, TREC Passage 19, TREC Passage 20, MS MARCO Document, TREC Document 19 and TREC Document 20.
translated by 谷歌翻译
知识蒸馏是将知识从强大的教师转移到有效的学生模型的有效方法。理想情况下,我们希望老师越好,学生越好。但是,这种期望并不总是成真。通常,由于教师和学生之间的不可忽略的差距,更好的教师模型通过蒸馏导致不良学生。为了弥合差距,我们提出了一种渐进式蒸馏方法,以进行致密检索。产品由教师渐进式蒸馏和数据进行渐进的蒸馏组成,以逐步改善学生。我们对五个广泛使用的基准,MARCO通道,TREC Passage 19,TREC文档19,MARCO文档和自然问题进行了广泛的实验,其中POD在蒸馏方法中实现了密集检索的最新方法。代码和模型将发布。
translated by 谷歌翻译
捕获不规则点云的局部和全局特征对于3D对象检测(3OD)至关重要。但是,主流3D探测器,例如,投票机及其变体,要么放弃池操作过程中的大量本地功能,要么忽略整个场景中的许多全球功能。本文探讨了新的模块,以同时学习积极服务3OD的场景点云的局部全球特征。为此,我们通过同时局部全球特征学习(称为3DLG-detector)提出了一个有效的3OD网络。 3DLG检测器有两个关键贡献。首先,它会开发一个动态点交互(DPI)模块,该模块可在合并过程中保留有效的本地特征。此外,DPI是可拆卸的,可以将其合并到现有的3OD网络中以提高其性能。其次,它开发了一个全局上下文聚合模块,以汇总编码器不同层的多尺度特征,以实现场景上下文意识。我们的方法在SUN RGB-D和扫描仪数据集的检测准确性和鲁棒性方面显示了13个竞争对手的进步。源代码将在出版物时提供。
translated by 谷歌翻译
在6G无线通信网络中,按需服务提供是一个至关重要的问题,因为新兴服务的需求大大不同,并且网络资源变得越来越异质和动态。在本文中,我们研究了按需无线资源编排问题,重点是编排决策过程的计算延迟。具体而言,我们将决策延迟延迟到优化问题。然后,提出了一个基于动态的神经网络(DYNN)的方法,可以根据服务要求调整模型复杂性。我们进一步建立一个知识库,代表服务需求之间的关系,可用的计算资源和资源分配绩效。通过利用知识,可以及时选择DYNN的宽度,从而进一步提高编排的性能。仿真结果表明,所提出的方案大大优于传统的静态神经网络,并且在按需服务提供方面也表现出足够的灵活性。
translated by 谷歌翻译
近年来,有监督的深度学习取得了巨大的成功,从大量完全标记的数据中,对预测模型进行了培训。但是,实际上,标记这样的大数据可能非常昂贵,甚至出于隐私原因甚至可能是不可能的。因此,在本文中,我们旨在学习一个无需任何类标签的准确分类器。更具体地说,我们考虑了多组未标记的数据及其类先验的情况,即每个类别的比例。在此问题设置下,我们首先得出了对分类风险的无偏估计量,可以从给定未标记的集合中估算,并理论上分析了学习分类器的概括误差。然后,我们发现获得的分类器往往会导致过度拟合,因为其经验风险在训练过程中呈负面。为了防止过度拟合,我们进一步提出了一个部分风险正规化,该风险正规化在某些级别上保持了未标记的数据集和类方面的部分风险。实验表明,我们的方法有效地减轻了过度拟合和优于从多个未标记集中学习的最先进方法。
translated by 谷歌翻译
监督学习的关键假设是培训和测试数据遵循相同的概率分布。然而,这种基本假设在实践中并不总是满足,例如,由于不断变化的环境,样本选择偏差,隐私问题或高标签成本。转移学习(TL)放松这种假设,并允许我们在分销班次下学习。通常依赖于重要性加权的经典TL方法 - 基于根据重要性(即测试过度训练密度比率)的训练损失培训预测器。然而,由于现实世界机器学习任务变得越来越复杂,高维和动态,探讨了新的新方法,以应对这些挑战最近。在本文中,在介绍基于重要性加权的TL基础之后,我们根据关节和动态重要预测估计审查最近的进步。此外,我们介绍一种因果机制转移方法,该方法包含T1中的因果结构。最后,我们讨论了TL研究的未来观点。
translated by 谷歌翻译
我们为来自多视图立体声(MVS)城市场景的3D建筑物的实例分割了一部小说框架。与关注城市场景的语义分割的现有作品不同,即使它们安装在大型和不精确的3D表面模型中,这项工作的重点是检测和分割3D构建实例。通过添加高度图,首先将多视图RGB图像增强到RGBH图像,并且被分段以使用微调的2D实例分割神经网络获得所有屋顶实例。然后将来自不同的多视图图像的屋顶实例掩码被聚集到全局掩码中。我们的面具聚类占空间闭塞和重叠,可以消除多视图图像之间的分割歧义。基于这些全局掩码,3D屋顶实例由掩码背部投影分割,并通过Markov随机字段(MRF)优化扩展到整个建筑实例。定量评估和消融研究表明了该方法的所有主要步骤的有效性。提供了一种用于评估3D建筑模型的实例分割的数据集。据我们所知,它是一个在实例分割级别的3D城市建筑的第一个数据集。
translated by 谷歌翻译
为了减轻二进制分类中培训有效二进制分类器的数据要求,已经提出了许多弱监督的学习设置。其中,当由于隐私,机密性或安全原因无法访问时,使用成对但不是尖标签的一些考虑。然而,作为一对标签表示两个数据点是否共享尖点标签,如果任一点同样可能是正的或负数,则不能容易地收集。因此,在本文中,我们提出了一种名为成对比较(PCOMP)分类的新颖设置,在那里我们只有一对未标记的数据,我们知道一个人比另一个更有可能是积极的。首先,我们提供了PCOMP数据生成过程,通过理论上保证导出了无偏的风险估计器(URE),并进一步提高了URE使用校正功能。其次,我们将PCOMP分类链接到嘈杂的标签学习,通过强加一致性正规化来开发渐进式,并改善它。最后,我们通过实验证明了我们的方法的有效性,这表明PCOMP是一种有价值的,实际上有用的成对监督类型,除了一对标签。
translated by 谷歌翻译
In this paper, we present a novel visual SLAM and long-term localization benchmark for autonomous driving in challenging conditions based on the large-scale 4Seasons dataset. The proposed benchmark provides drastic appearance variations caused by seasonal changes and diverse weather and illumination conditions. While significant progress has been made in advancing visual SLAM on small-scale datasets with similar conditions, there is still a lack of unified benchmarks representative of real-world scenarios for autonomous driving. We introduce a new unified benchmark for jointly evaluating visual odometry, global place recognition, and map-based visual localization performance which is crucial to successfully enable autonomous driving in any condition. The data has been collected for more than one year, resulting in more than 300 km of recordings in nine different environments ranging from a multi-level parking garage to urban (including tunnels) to countryside and highway. We provide globally consistent reference poses with up to centimeter-level accuracy obtained from the fusion of direct stereo-inertial odometry with RTK GNSS. We evaluate the performance of several state-of-the-art visual odometry and visual localization baseline approaches on the benchmark and analyze their properties. The experimental results provide new insights into current approaches and show promising potential for future research. Our benchmark and evaluation protocols will be available at https://www.4seasons-dataset.com/.
translated by 谷歌翻译