Location privacy leaks can lead to unauthorised tracking, identity theft, and targeted attacks, compromising personal security and privacy. This study explores LLM-powered location privacy leaks associated with photo sharing on social media, focusing on user awareness, attitudes, and opinions. We developed and introduced an LLM-powered location privacy intervention app to 19 participants, who used it over a two-week period. The app prompted users to reflect on potential privacy leaks that a widely available LLM could easily detect, such as visual landmarks & cues that could reveal their location, and provided ways to conceal this information. Through in-depth interviews, we found that our intervention effectively increased users' awareness of location privacy and the risks posed by LLMs. It also encouraged users to consider the importance of maintaining control over their privacy data and sparked discussions about the future of location privacy-preserving technologies. Based on these insights, we offer design implications to support the development of future user-centred, location privacy-preserving technologies for social media photos.

Conventional consensus algorithms, such as Paxos and Raft, encounter inefficiencies when applied to large-scale distributed systems due to the requirement of waiting for replies from a majority of nodes. To address these challenges, we propose Cabinet, a novel consensus algorithm that introduces dynamically weighted consensus, allocating distinct weights to nodes based on any given failure thresholds. Cabinet dynamically adjusts nodes' weights according to their responsiveness, assigning higher weights to faster nodes. The dynamic weight assignment maintains an optimal system performance, especially in large-scale and heterogeneous systems where node responsiveness varies. We evaluate Cabinet against Raft with distributed MongoDB and PostgreSQL databases using YCSB and TPC-C workloads. The evaluation results show that Cabinet outperforms Raft in throughput and latency under increasing system scales, complex networks, and failures in both homogeneous and heterogeneous clusters, offering a promising high-performance consensus solution.

Journaling offers significant benefits, including fostering self-reflection, enhancing writing skills, and aiding in mood monitoring. However, many people abandon the practice because traditional journaling is time-consuming, and detailed life events may be overlooked if not recorded promptly. Given that smartphones are the most widely used devices for entertainment, work, and socialization, they present an ideal platform for innovative approaches to journaling. Despite their ubiquity, the potential of using digital phenotyping, a method of unobtrusively collecting data from digital devices to gain insights into psychological and behavioral patterns, for automated journal generation has been largely underexplored. In this study, we propose AutoJournaling, the first-of-its-kind system that automatically generates journals by collecting and analyzing screenshots from smartphones. This system captures life events and corresponding emotions, offering a novel approach to digital phenotyping. We evaluated AutoJournaling by collecting screenshots every 3 seconds from three students over five days, demonstrating its feasibility and accuracy. AutoJournaling is the first framework to utilize seamlessly collected screenshots for journal generation, providing new insights into psychological states through digital phenotyping.

Multi-View 3D object detection (MV3D) has made tremendous progress by leveraging multiple perspective features through surrounding cameras. Despite demonstrating promising prospects in various applications, accurately detecting objects through camera view in the 3D space is extremely difficult due to the ill-posed issue in monocular depth estimation. Recently, Graph-DETR3D presents a novel graph-based 3D-2D query paradigm in aggregating multi-view images for 3D object detection and achieves competitive performance. Although it enriches the query representations with 2D image features through a learnable 3D graph, it still suffers from limited depth and velocity estimation abilities due to the adoption of a single-frame input setting. To solve this problem, we introduce a unified spatial-temporal graph modeling framework to fully leverage the multi-view imagery cues under the multi-frame inputs setting. Thanks to the flexibility and sparsity of the dynamic graph architecture, we lift the original 3D graph into the 4D space with an effective attention mechanism to automatically perceive imagery information at both spatial and temporal levels. Moreover, considering the main latency bottleneck lies in the image backbone, we propose a novel dense-sparse distillation framework for multi-view 3D object detection, to reduce the computational budget while sacrificing no detection accuracy, making it more suitable for real-world deployment. To this end, we propose Graph-DETR4D, a faster and stronger multi-view 3D object detection framework, built on top of Graph-DETR3D. Extensive experiments on nuScenes and Waymo benchmarks demonstrate the effectiveness and efficiency of Graph-DETR4D. Notably, our best model achieves 62.0% NDS on nuScenes test leaderboard. Code is available at https://github.com/zehuichen123/Graph-DETR4D.

Object detection through either RGB images or the LiDAR point clouds has been extensively explored in autonomous driving. However, it remains challenging to make these two data sources complementary and beneficial to each other. In this paper, we propose AutoAlign, an automatic feature fusion strategy for 3D object detection. Instead of establishing deterministic correspondence with camera projection matrix, we model the mapping relationship between the image and point clouds with a learnable alignment map. This map enables our model to automate the alignment of non-homogenous features in a dynamic and data-driven manner. Specifically, a cross-attention feature alignment module is devised to adaptively aggregate pixel-level image features for each voxel. To enhance the semantic consistency during feature alignment, we also design a self-supervised cross-modal feature interaction module, through which the model can learn feature aggregation with instance-level feature guidance. Extensive experimental results show that our approach can lead to 2.3 mAP and 7.0 mAP improvements on the KITTI and nuScenes datasets respectively. Notably, our best model reaches 70.9 NDS on the nuScenes testing leaderboard, achieving competitive performance among various state-of-the-arts.

3D object detection from multiple image views is a fundamental and challenging task for visual scene understanding. However, accurately detecting objects through perspective views in the 3D space is extremely difficult due to the lack of depth information. Recently, DETR3D introduces a novel 3D-2D query paradigm in aggregating multi-view images for 3D object detection and achieves state-of-the-art performance. In this paper, with intensive pilot experiments, we quantify the objects located at different regions and find that the "truncated instances'' (i.e., at the border regions of each image) are the main bottleneck hindering the performance of DETR3D. Although it merges multiple features from two adjacent views in the overlapping regions, DETR3D still suffers from insufficient feature aggregation, thus missing the chance to fully boost the detection performance. In an effort to tackle the problem, we propose Graph-DETR3D to automatically aggregate multi-view imagery information through graph structure learning. It constructs a dynamic 3D graph between each object query and 2D feature maps to enhance the object representations, especially at the border regions. Besides, Graph-DETR3D benefits from a novel depth-invariant multi-scale training strategy, which maintains the visual depth consistency by simultaneously scaling the image size and the object depth. Extensive experiments on the nuScenes dataset demonstrate the effectiveness and efficiency of our Graph-DETR3D. Notably, our best model achieves 49.5 NDS on the nuScenes test leaderboard, achieving new state-of-the-art in comparison with various published image-view 3D object detectors.

Single object tracking in visual media is an important yet challenging task. Various challenges, especially target scale variation, shape deformation and occlusion, can have large effects on the performances of trackers. Current deep regression based trackers only pay close attention to regression on the center key point of the tracking target, meanwhile employ the image pyramid based multi-scale testing method to deal with scale estimation. Such procedure can not properly handle the three challenges. We address these challenges in a principled way by the aid of auxiliary regressions on the four bounding box corners of the tracking target. In this work, we propose the novel Corner Aided Tracker with deep regression network, abbreviated as CAT. Different from RPN-based trackers, in CAT, four corners along with the center key point of the bounding box for tracking target are simultaneously obtained by five corresponding response maps. Furthermore, to robustly and accurately generate tight bounding boxes for the tracking target and collect reliable samples for online training of the network, we propose an adaptive key point selection method to select the subset of reliable key points and drop the unreliable ones, based on the qualities of their corresponding response maps as well as the constraints from shape, scale and location. We demonstrate that the regressed corners can help naturally locate the tracking target with tight bounding boxes. The challenges of scale variation, shape deformation and occlusion can be handled explicitly. The commonly used time-consuming image pyramid based multi-scale testing method can also be discarded. Extensive experiments on OTB2013, OTB2015, UAV123, LaSOT, VOT2016 and VOT2018 datasets are conducted to report new state-of-the-art performances and demonstrate the effectiveness of CAT.

Classification subnetwork and box regression subnetwork are essential components in deep networks for object detection. However, we observe a contradiction that before NMS, some better localized detections do not correspond to higher classification confidences, and vice versa. This contradiction exists because classification confidences can not fully reflect the localization-quality (loc-quality) of each detection. In this work, we propose the Localization-quality Estimation embedded Detector abbreviated as LED, and a corresponding detection pipeline. In this detection pipeline, we first propose an accurate loc-quality estimation method for each detection, then combine the loc-quality with the corresponding classification confidence during inference to make each detection more reasonable and accurate. For efficiency, LED is designed as an one-stage network. Extensive experiments are conducted on Pascal VOC 2007 and KITTI car detection datasets to demonstrate the effectiveness of LED.