Recently, the self-supervised pre-training paradigm has shown great potential in leveraging large-scale unlabeled data to improve downstream task performance. However, increasing the scale of unlabeled pre-training data in real-world scenarios requires prohibitive computational costs and faces the challenge of uncurated samples. To address these issues, we build a task-specific self-supervised pre-training framework from a data selection perspective based on a simple hypothesis that pre-training on the unlabeled samples with similar distribution to the target task can bring substantial performance gains. Buttressed by the hypothesis, we propose the first yet novel framework for Scalable and Efficient visual Pre-Training (SEPT) by introducing a retrieval pipeline for data selection. SEPT first leverage a self-supervised pre-trained model to extract the features of the entire unlabeled dataset for retrieval pipeline initialization. Then, for a specific target task, SEPT retrievals the most similar samples from the unlabeled dataset based on feature similarity for each target instance for pre-training. Finally, SEPT pre-trains the target model with the selected unlabeled samples in a self-supervised manner for target data finetuning. By decoupling the scale of pre-training and available upstream data for a target task, SEPT achieves high scalability of the upstream dataset and high efficiency of pre-training, resulting in high model architecture flexibility. Results on various downstream tasks demonstrate that SEPT can achieve competitive or even better performance compared with ImageNet pre-training while reducing the size of training samples by one magnitude without resorting to any extra annotations.

多代理协作感知可以通过使代理商能够通过交流相互共享互补信息来显着升级感知表现。它不可避免地会导致感知表现与沟通带宽之间的基本权衡。为了解决这个瓶颈问题，我们提出了一个空间置信度图，该图反映了感知信息的空间异质性。它使代理只能在空间上共享稀疏而感知的关键信息，从而有助于沟通。基于这张新型的空间置信度图，我们提出了2Comm，即沟通有效的协作感知框架。其中2Comm具有两个不同的优势：i）它考虑了实用的压缩，并使用较少的沟通来通过专注于感知至关重要的领域来实现更高的感知表现； ii）它可以通过动态调整涉及通信的空间区域来处理不同的通信带宽。要评估2comm的位置，我们考虑了在现实世界和模拟方案中使用两种模式（相机/激光镜头）和两种代理类型（CAR/无人机）的3D对象检测：OPV2V，v2x-sim，dair-v2x和我们的原始的Coperception-uavs。其中2comm始终优于先前的方法；例如，它实现了超过$ 100,000 \ times $较低的通信量，并且在OPV2V上仍然优于脱颖而出和v2x-vit。我们的代码可在https://github.com/mediabrain-sjtu/where2comm上找到。

以前通过一个位置的历史轨迹可能有助于推断该位置当前代理的未来轨迹。尽管在高清图的指导下进行了轨迹预测的大大改善，但只有少数作品探讨了这种当地历史信息。在这项工作中，我们将这些信息重新引入了轨迹预测系统的新类型的输入数据：本地行为数据，我们将其概念化为特定于位置的历史轨迹的集合。局部行为数据有助于系统强调预测区域，并更好地了解静态地图对象对移动代理的影响。我们提出了一个新型的本地行为感知（LBA）预测框架，该框架通过从观察到的轨迹，高清图和局部行为数据中融合信息来提高预测准确性。同样，如果这种历史数据不足或不可用，我们采用了本地行为（LBF）预测框架，该框架采用了基于知识依据的架构来推断缺失数据的影响。广泛的实验表明，通过这两个框架升级现有方法可显着提高其性能。特别是，LBA框架将SOTA方法在Nuscenes数据集上的性能提高了至少14％的K = 1度量。

在多模式的多代理轨迹预测中，尚未完全解决两个主要挑战：1）如何测量相互作用模块引起的不确定性，从而导致多个试剂的预测轨迹之间引起相关性； 2）如何对多个预测进行排名并选择最佳预测轨迹。为了应对这些挑战，这项工作首先提出了一个新颖的概念，协作不确定性（CU），该概念模拟了互动模块引起的不确定性。然后，我们使用原始置换量等不确定性估计器来构建一般的CU感知回归框架，以完成回归和不确定性估计任务。此外，我们将提出的框架应用于当前的SOTA多代理多模式预测系统作为插件模块，该模块使SOTA系统能够达到1）估计多代理多模式轨迹预测任务的不确定性； 2）对多个预测进行排名，并根据估计的不确定性选择最佳预测。我们对合成数据集和两个公共大规模多代理轨迹预测基准进行了广泛的实验。实验表明：1）在合成数据集上，Cu-Aware回归框架允许模型适当地近似地面真相拉普拉斯分布； 2）在多代理轨迹预测基准上，Cu-Aware回归框架稳步帮助SOTA系统改善了其性能。特别是，提出的框架帮助Vectornet在Nuscenes数据集中所选最佳预测的最终位移误差方面提高了262 cm； 3）对于多机构多模式轨迹预测系统，预测不确定性与未来随机性呈正相关； 4）估计的CU值与代理之间的交互式信息高度相关。

车辆到所有（V2X）通信技术使车辆与附近环境中许多其他实体之间的协作可以从根本上改善自动驾驶的感知系统。但是，缺乏公共数据集极大地限制了协作感知的研究进度。为了填补这一空白，我们提出了V2X-SIM，这是一个针对V2X辅助自动驾驶的全面模拟多代理感知数据集。 V2X-SIM提供：（1）\ hl {Multi-Agent}传感器记录来自路边单元（RSU）和多种能够协作感知的车辆，（2）多模式传感器流，可促进多模式感知和多模式感知和（3）支持各种感知任务的各种基础真理。同时，我们在三个任务（包括检测，跟踪和细分）上为最先进的协作感知算法提供了一个开源测试台，并为最先进的协作感知算法提供了基准。 V2X-SIM试图在现实数据集广泛使用之前刺激自动驾驶的协作感知研究。我们的数据集和代码可在\ url {https://ai4ce.github.io/v2x-sim/}上获得。

激光器传感器的进步提供了支持3D场景了解的丰富的3D数据。然而，由于遮挡和信号未命中，LIDAR点云实际上是2.5D，因为它们仅覆盖部分底层形状，这对3D感知构成了根本挑战。为了解决挑战，我们提出了一种基于新的LIDAR的3D对象检测模型，被称为窗帘检测器（BTCDET）后面，该模型学习物体形状前沿并估计在点云中部分封闭（窗帘）的完整物体形状。 BTCDET首先识别受遮挡和信号未命中的影响的区域。在这些区域中，我们的模型预测了占用的概率，指示区域是否包含对象形状。与此概率图集成，BTCDET可以产生高质量的3D提案。最后，占用概率也集成到提案细化模块中以生成最终边界框。关于基蒂数据集的广泛实验和Waymo Open DataSet展示了BTCDET的有效性。特别是，对于Kitti基准测试的汽车和骑自行车者的3D检测，BTCDET通过显着的边缘超越所有公布的最先进的方法。代码已发布（https://github.com/xharlie/btcdet}（https：//github.com/xharlie/btcdet）。

A recent study has shown a phenomenon called neural collapse in that the within-class means of features and the classifier weight vectors converge to the vertices of a simplex equiangular tight frame at the terminal phase of training for classification. In this paper, we explore the corresponding structures of the last-layer feature centers and classifiers in semantic segmentation. Based on our empirical and theoretical analysis, we point out that semantic segmentation naturally brings contextual correlation and imbalanced distribution among classes, which breaks the equiangular and maximally separated structure of neural collapse for both feature centers and classifiers. However, such a symmetric structure is beneficial to discrimination for the minor classes. To preserve these advantages, we introduce a regularizer on feature centers to encourage the network to learn features closer to the appealing structure in imbalanced semantic segmentation. Experimental results show that our method can bring significant improvements on both 2D and 3D semantic segmentation benchmarks. Moreover, our method ranks 1st and sets a new record (+6.8% mIoU) on the ScanNet200 test leaderboard. Code will be available at https://github.com/dvlab-research/Imbalanced-Learning.

Although deep learning has made remarkable progress in processing various types of data such as images, text and speech, they are known to be susceptible to adversarial perturbations: perturbations specifically designed and added to the input to make the target model produce erroneous output. Most of the existing studies on generating adversarial perturbations attempt to perturb the entire input indiscriminately. In this paper, we propose ExploreADV, a general and flexible adversarial attack system that is capable of modeling regional and imperceptible attacks, allowing users to explore various kinds of adversarial examples as needed. We adapt and combine two existing boundary attack methods, DeepFool and Brendel\&Bethge Attack, and propose a mask-constrained adversarial attack system, which generates minimal adversarial perturbations under the pixel-level constraints, namely ``mask-constraints''. We study different ways of generating such mask-constraints considering the variance and importance of the input features, and show that our adversarial attack system offers users good flexibility to focus on sub-regions of inputs, explore imperceptible perturbations and understand the vulnerability of pixels/regions to adversarial attacks. We demonstrate our system to be effective based on extensive experiments and user study.

Recently the deep learning has shown its advantage in representation learning and clustering for time series data. Despite the considerable progress, the existing deep time series clustering approaches mostly seek to train the deep neural network by some instance reconstruction based or cluster distribution based objective, which, however, lack the ability to exploit the sample-wise (or augmentation-wise) contrastive information or even the higher-level (e.g., cluster-level) contrastiveness for learning discriminative and clustering-friendly representations. In light of this, this paper presents a deep temporal contrastive clustering (DTCC) approach, which for the first time, to our knowledge, incorporates the contrastive learning paradigm into the deep time series clustering research. Specifically, with two parallel views generated from the original time series and their augmentations, we utilize two identical auto-encoders to learn the corresponding representations, and in the meantime perform the cluster distribution learning by incorporating a k-means objective. Further, two levels of contrastive learning are simultaneously enforced to capture the instance-level and cluster-level contrastive information, respectively. With the reconstruction loss of the auto-encoder, the cluster distribution loss, and the two levels of contrastive losses jointly optimized, the network architecture is trained in a self-supervised manner and the clustering result can thereby be obtained. Experiments on a variety of time series datasets demonstrate the superiority of our DTCC approach over the state-of-the-art.

Accurate and smooth global navigation satellite system (GNSS) positioning for pedestrians in urban canyons is still a challenge due to the multipath effects and the non-light-of-sight (NLOS) receptions caused by the reflections from surrounding buildings. The recently developed factor graph optimization (FGO) based GNSS positioning method opened a new window for improving urban GNSS positioning by effectively exploiting the measurement redundancy from the historical information to resist the outlier measurements. Unfortunately, the FGO-based GNSS standalone positioning is still challenged in highly urbanized areas. As an extension of the previous FGO-based GNSS positioning method, this paper exploits the potential of the pedestrian dead reckoning (PDR) model in FGO to improve the GNSS standalone positioning performance in urban canyons. Specifically, the relative motion of the pedestrian is estimated based on the raw acceleration measurements from the onboard smartphone inertial measurement unit (IMU) via the PDR algorithm. Then the raw GNSS pseudorange, Doppler measurements, and relative motion from PDR are integrated using the FGO. Given the context of pedestrian navigation with a small acceleration most of the time, a novel soft motion model is proposed to smooth the states involved in the factor graph model. The effectiveness of the proposed method is verified step-by-step through two datasets collected in dense urban canyons of Hong Kong using smartphone-level GNSS receivers. The comparison between the conventional extended Kalman filter, several existing methods, and FGO-based integration is presented. The results reveal that the existing FGO-based GNSS standalone positioning is highly complementary to the PDR's relative motion estimation. Both improved positioning accuracy and trajectory smoothness are obtained with the help of the proposed method.