生成的开放域对话系统可以从外部知识中受益，但是缺乏外部知识资源和寻找相关知识的困难限制了该技术的发展。为此，我们使用动态服务信息提出了一个知识驱动的对话任务。具体而言，我们使用大量的服务API，可以作为外部知识来源提供高覆盖范围和时空敏感性。对话系统生成查询以请求外部服务以及用户信息，获取相关知识，并基于此知识生成响应。为了实现此方法，我们收集并发布了第一个开放式域中国服务知识对话数据集Dusinc。同时，我们构建了一个基线模型柏拉图 - 线，该模型实现了对话的自动利用。自动评估和人类评估都表明，我们提出的新方法可以显着改善开放域对话的效果，并且与对话预培训模型Plato-2相比，人类评估中的会话级总数提高了59.29％。数据集和基准模型将被开源。

Recently, Vehicle-to-Everything(V2X) cooperative perception has attracted increasing attention. Infrastructure sensors play a critical role in this research field, however, how to find the optimal placement of infrastructure sensors is rarely studied. In this paper, we investigate the problem of infrastructure sensor placement and propose a pipeline that can efficiently and effectively find optimal installation positions for infrastructure sensors in a realistic simulated environment. To better simulate and evaluate LiDAR placement, we establish a Realistic LiDAR Simulation library that can simulate the unique characteristics of different popular LiDARs and produce high-fidelity LiDAR point clouds in the CARLA simulator. Through simulating point cloud data in different LiDAR placements, we can evaluate the perception accuracy of these placements using multiple detection models. Then, we analyze the correlation between the point cloud distribution and perception accuracy by calculating the density and uniformity of regions of interest. Experiments show that the placement of infrastructure LiDAR can heavily affect the accuracy of perception. We also analyze the correlation between perception performance in the region of interest and LiDAR point cloud distribution and validate that density and uniformity can be indicators of performance.

单元实例分割是一项旨在针对图像中每个单元格的联合检测和分割的新任务。最近，在此任务中应用了许多实例细分方法。尽管取得了巨大的成功，但仍然存在两个主要弱点，这是由于定位细胞中心点的不确定性而引起的。首先，可以很容易地将密集的填充细胞识别到一个细胞中。其次，细胞的细胞很容易被识别为两个细胞。为了克服这两个弱点，我们提出了一个基于多控制回归指南的新细胞实例分割网络。借助多功能回归指导，该网络具有不同视图中每个单元格的能力。具体而言，我们首先提出了一种高斯指导注意机制，以使用高斯标签来指导网络的注意力。然后，我们提出了一个点回归模块，以帮助细胞中心的回归。最后，我们利用上述两个模块的输出来进一步指导实例分割。借助多轮回归指导，我们可以充分利用不同区域的特征，尤其是细胞的中心区域。我们在基准数据集，DSB2018，CA2.5和SCIS上进行了广泛的实验。令人鼓舞的结果表明，我们的网络实现了SOTA（最先进的）性能。在DSB2018和CA2.5上，我们的网络超过1.2％（AP50）。尤其是在SCIS数据集上，我们的网络的性能较大（AP50高3.0％）。可视化和分析进一步证明了我们提出的方法是可以解释的。

人重新识别（Reid）旨在从不同摄像机捕获的图像中检索一个人。对于基于深度学习的REID方法，已经证明，使用本地特征与人物图像的全局特征可以帮助为人员检索提供强大的特征表示。人类的姿势信息可以提供人体骨架的位置，有效地指导网络在这些关键领域更加关注这些关键领域，也可能有助于减少来自背景或闭塞的噪音分散。然而，先前与姿势相关的作品提出的方法可能无法充分利用姿势信息的好处，并没有考虑不同当地特征的不同贡献。在本文中，我们提出了一种姿势引导图注意网络，一个多分支架构，包括一个用于全局特征的一个分支，一个用于中粒体特征的一个分支，一个分支用于细粒度关键点特征。我们使用预先训练的姿势估计器来生成本地特征学习的关键点热图，并仔细设计图表卷积层以通过建模相似关系来重新评估提取的本地特征的贡献权重。实验结果表明我们对歧视特征学习的方法的有效性，我们表明我们的模型在几个主流评估数据集上实现了最先进的表演。我们还对我们的网络进行了大量的消融研究和设计不同类型的比较实验，以证明其有效性和鲁棒性，包括整体数据集，部分数据集，遮挡数据集和跨域测试。

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.

Weakly-supervised object localization aims to indicate the category as well as the scope of an object in an image given only the image-level labels. Most of the existing works are based on Class Activation Mapping (CAM) and endeavor to enlarge the discriminative area inside the activation map to perceive the whole object, yet ignore the co-occurrence confounder of the object and context (e.g., fish and water), which makes the model inspection hard to distinguish object boundaries. Besides, the use of CAM also brings a dilemma problem that the classification and localization always suffer from a performance gap and can not reach their highest accuracy simultaneously. In this paper, we propose a casual knowledge distillation method, dubbed KD-CI-CAM, to address these two under-explored issues in one go. More specifically, we tackle the co-occurrence context confounder problem via causal intervention (CI), which explores the causalities among image features, contexts, and categories to eliminate the biased object-context entanglement in the class activation maps. Based on the de-biased object feature, we additionally propose a multi-teacher causal distillation framework to balance the absorption of classification knowledge and localization knowledge during model training. Extensive experiments on several benchmarks demonstrate the effectiveness of KD-CI-CAM in learning clear object boundaries from confounding contexts and addressing the dilemma problem between classification and localization performance.

Witnessing the impressive achievements of pre-training techniques on large-scale data in the field of computer vision and natural language processing, we wonder whether this idea could be adapted in a grab-and-go spirit, and mitigate the sample inefficiency problem for visuomotor driving. Given the highly dynamic and variant nature of the input, the visuomotor driving task inherently lacks view and translation invariance, and the visual input contains massive irrelevant information for decision making, resulting in predominant pre-training approaches from general vision less suitable for the autonomous driving task. To this end, we propose PPGeo (Policy Pre-training via Geometric modeling), an intuitive and straightforward fully self-supervised framework curated for the policy pretraining in visuomotor driving. We aim at learning policy representations as a powerful abstraction by modeling 3D geometric scenes on large-scale unlabeled and uncalibrated YouTube driving videos. The proposed PPGeo is performed in two stages to support effective self-supervised training. In the first stage, the geometric modeling framework generates pose and depth predictions simultaneously, with two consecutive frames as input. In the second stage, the visual encoder learns driving policy representation by predicting the future ego-motion and optimizing with the photometric error based on current visual observation only. As such, the pre-trained visual encoder is equipped with rich driving policy related representations and thereby competent for multiple visuomotor driving tasks. Extensive experiments covering a wide span of challenging scenarios have demonstrated the superiority of our proposed approach, where improvements range from 2% to even over 100% with very limited data. Code and models will be available at https://github.com/OpenDriveLab/PPGeo.

In this work, we focus on instance-level open vocabulary segmentation, intending to expand a segmenter for instance-wise novel categories without mask annotations. We investigate a simple yet effective framework with the help of image captions, focusing on exploiting thousands of object nouns in captions to discover instances of novel classes. Rather than adopting pretrained caption models or using massive caption datasets with complex pipelines, we propose an end-to-end solution from two aspects: caption grounding and caption generation. In particular, we devise a joint Caption Grounding and Generation (CGG) framework based on a Mask Transformer baseline. The framework has a novel grounding loss that performs explicit and implicit multi-modal feature alignments. We further design a lightweight caption generation head to allow for additional caption supervision. We find that grounding and generation complement each other, significantly enhancing the segmentation performance for novel categories. We conduct extensive experiments on the COCO dataset with two settings: Open Vocabulary Instance Segmentation (OVIS) and Open Set Panoptic Segmentation (OSPS). The results demonstrate the superiority of our CGG framework over previous OVIS methods, achieving a large improvement of 6.8% mAP on novel classes without extra caption data. Our method also achieves over 15% PQ improvements for novel classes on the OSPS benchmark under various settings.

Nearest-Neighbor (NN) classification has been proven as a simple and effective approach for few-shot learning. The query data can be classified efficiently by finding the nearest support class based on features extracted by pretrained deep models. However, NN-based methods are sensitive to the data distribution and may produce false prediction if the samples in the support set happen to lie around the distribution boundary of different classes. To solve this issue, we present P3DC-Shot, an improved nearest-neighbor based few-shot classification method empowered by prior-driven data calibration. Inspired by the distribution calibration technique which utilizes the distribution or statistics of the base classes to calibrate the data for few-shot tasks, we propose a novel discrete data calibration operation which is more suitable for NN-based few-shot classification. Specifically, we treat the prototypes representing each base class as priors and calibrate each support data based on its similarity to different base prototypes. Then, we perform NN classification using these discretely calibrated support data. Results from extensive experiments on various datasets show our efficient non-learning based method can outperform or at least comparable to SOTA methods which need additional learning steps.

In this tutorial paper, we look into the evolution and prospect of network architecture and propose a novel conceptual architecture for the 6th generation (6G) networks. The proposed architecture has two key elements, i.e., holistic network virtualization and pervasive artificial intelligence (AI). The holistic network virtualization consists of network slicing and digital twin, from the aspects of service provision and service demand, respectively, to incorporate service-centric and user-centric networking. The pervasive network intelligence integrates AI into future networks from the perspectives of networking for AI and AI for networking, respectively. Building on holistic network virtualization and pervasive network intelligence, the proposed architecture can facilitate three types of interplay, i.e., the interplay between digital twin and network slicing paradigms, between model-driven and data-driven methods for network management, and between virtualization and AI, to maximize the flexibility, scalability, adaptivity, and intelligence for 6G networks. We also identify challenges and open issues related to the proposed architecture. By providing our vision, we aim to inspire further discussions and developments on the potential architecture of 6G.