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Real-time Monocular 3D Pose Tracking for Non-cooperative Spacecraft in Close Range

IEEE Transactions on Instrumentation and Measurement 2025年

作者： Tang, Hao Liu, Chang Liu, Jia Zhang, Pandeng Hu, Weiduo Chinese Academy of Sciences Shenzhen Institutes of Advanced Technology Shenzhen China Shenzhen Key Laboratory for Exascale Engineering and Scientific Computing Shenzhen China University of Chinese Academy of Sciences Beijing China Beihang University School of Astronautics Beijing China

Real-time pose tracking for noncooperative spacecraft is crucial for numerous space missions, such as debris removal and docking. Existing pose tracking methods either suffer from shadow occlusion and cluttered backgrounds in space or lack computational efficiency. This study proposes a real-time system for tracking the 6-degree-of-freedom pose of a noncooperative spacecraft for proximity operations using a single calibrated camera. The proposed method parameterizes the pose in the Lie group of SE(3) and exploits the 3D boundaries and 3D contour, which are automatically extracted from the 3D model of the spacecraft as geometric features (GFs). At each frame of the tracking process, the initial pose is predicted using an error state Kalman filter (ESKF). Using the initial pose, the tracking system searches the input image for the 2D edge points that are associated with the 3D GFs based on a conditional random field and then rapidly determines the spacecraft pose in SE(3) by minimizing the distances of the projected 3D GFs to their corresponding 2D edge points using the M-estimation and Newton’s method. The covariance of the optimized pose is estimated based on the Karush–Kuhn–Tucker condition for pose optimization. With the estimated pose covariance, the ESKF is developed based on second-order autoregression in SE(3) to produce the maximum a posteriori estimate of the pose and initialize the pose tracking at the next frame. A sufficient number of synthetic and real trials indicate that the proposed method outperforms the existing methods in terms of accuracy and efficiency. The experimental results reveal that the proposed method achieves a rotation angle error of approximately 0.5° and relative position error of approximately 0.6% and that the average runtime of the proposed method is approximately 0.02 seconds per frame. © 1963-2012 IEEE.

关键词： 3D pose tracking geometric feature Kalman filter non-cooperative spacecraft Trigonometric polynomial

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LaTLS: A Lattice-Based TLS Proxy Protocol

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Chinese Journal of Electronics 2022年第2期31卷 313-321页

作者： ZHANG Xinglong CHENG Qingfeng LI Yuting State Key Laboratory of Mathematical Engineering and Advanced Computing

The function of the Internet proxy is to check and convert the data exchanged between client and server. In fact, the two-party secure communication protocol with good security is turned into an unsafe multiparty protocol. At present, there are relatively few proxy protocols that can be applied in practice. This paper analyzes the classic agent protocol mcTLS and pointed out the security issues. We focus on the security of TLS 1.3 and proposed a lattice-based multi-party proxy protocol:La TLS. LaTLS can be proved secure in the eCK model, it can resist key-sharing attacks, counterfeiting attacks, replay attacks, and achieve forward security. Compared with traditional DH and ECDH schemes, LaTLS is more effcient. Its security is based on the shortest vector problem, therefor it has anti-quantum attack properties.

关键词： security issues Internet lattice-based multiparty proxy protocol relatively few proxy protocols data exchanged LaTLS key sharing attacks unsafe multiparty protocol Internet proxy shortest vector problem protocols antiquantum attack properties forward security two-party secure communication protocol classic agent protocol mcTLS classic agent protocol computer network security

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Model-based kinetics of heavy metal enrichment in plants affected by hydrodynamics

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Journal of Contaminant Hydrology 2025年 273卷 104610页

作者： Lou, Sha Zhang, Zhirui Liu, Shuguang Yang, Zhongyuan Chen, Shizhe Zou, Yuwen Fedorova, Irina Viktorovna Department of Hydraulic Engineering College of Civil Engineering Tongji University Shanghai200092 China Key Laboratory of Yangtze River Water Environment Ministry of Education Tongji University Shanghai200092 China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji University Shanghai200092 China Project Management Office of China National Scientific Seafloor Observatory Tongji University Shanghai200092 China Institute of Earth Sciences Saint Petersburg State University 7-9 Universitetskaya Embankment St Petersburg199034 Russia

Heavy metal contamination threatens aquatic ecosystems by degrading water quality, biodiversity, and ecological stability. However, the role of hydrodynamics in modulating metal distribution and biogeochemical cycling, particularly in water-sediment-plant systems, remains unclear. Therefore, circular flume experiments were integrated with multiphase kinetic modeling to unravel cadmium (Cd) kinetics in water-sediment-plant systems under flow conditions. Affected by hydrodynamics, the distribution of Cd surged within 2 h and the Cd distribution coefficients showed a desorption peak within 8 h from the start of the experiment followed by reabsorption, and the hydrodynamic strength was negatively correlated with the resorption degree. Plant enrichment of heavy metals under hydrodynamics was observed initially, reaching a peak at the end of the experiment with phyto-sediment distribution coefficients of 0.22–0.25. The pseudo-second-order kinetic model effectively simulated the desorption of Cd from water, with r2 > 0.97. However, the Plant Enrichment Factor (PEF) failed to accurately describe the plant enrichment kinetics of the water-sediment-plant system under hydrodynamic conditions, with the r2 of cumulative Cd uptake kinetic of plants based on PEF lower than 0.77. Consequently, the nonlinear relationship of Cd in a multi-medium distribution was identified using the Artificial Neural Network (ANN), and a modified PEF was proposed, with r2 > 0.96. From the modified PEF, the competitive advantage of the phytobiological action was emphasized as the experiment proceeded. The modified model proposed in this study explains the physical process of Cd enrichment by plants in the water-sediment-plant system under hydrodynamics, providing a feasible tool for the study of pollutant transport in aquatic environments, and the results can contribute to theoretical support for optimizing wetland ecosystem protection strategies. © 2025 Elsevier B.V.

关键词： Aquatic ecosystems

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Detection of Malicious PDF Files Using a Two-Stage Machine Learning Algorithm

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Chinese Journal of Electronics 2020年第6期29卷 1165-1177页

作者： HE Kang ZHU Yuefei HE Yubo LIU Long LU Bin LIN Wei State Key Laboratory of Mathematical Engineering and Advanced Computing

Portable document format(PDF) files are increasingly used to launch cyberattacks due to their popularity and increasing number of *** solutions have been developed to detect malicious files,but their accuracy decreases rapidly in face of new evasion *** explore how to improve the robustness of classifiers for detecting adversarial attacks in PDF *** replacement and the n-gram are implemented to extract robust features using proposed guiding *** the two-stage machine learning model,the objects are divided based on their types,and the anomaly detection model is first trained for each type *** former detection results are organized into tree-like information structure and treated as inputs to convolutional neural *** results show that the accuracy of our classifier is nearly 100% and the robustness against evasive samples is *** object features also enable the identification of different vulnerabilities exploited in malicious PDF files.

关键词： convolutional neural nets document handling feature extraction learning (artificial intelligence) pattern classification security of data trees (mathematics) robust feature extraction convolutional neural network tree-like information structure adversarial attack detection two-stage machine learning algorithm evasion techniques malicious files portable document format malicious PDF files classifier robustness anomaly detection model two-stage machine learning model Malicious PDF classification Robustness Guiding principles Two-stage classifier Convolutional neural network

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Effects of appendages on the turbulence and flow noise of a submarine model using high-order scheme

arXiv

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arXiv 2025年

作者： Jiang, Peng Liao, Shijun Liu, Ling Xie, Bin School of Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai200240 China State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai200240 China China Ship Scientific Research Center Wuxi214082 China Taihu Laboratory of Deepsea Technological Science Wuxi214082 China

This study employs high-fidelity numerical simulations to investigate the influence of appendages on the turbulent flow dynamics and far-field acoustic radiation of the SUBOFF submarine model at a Reynolds number of Re = 1.2 × 107. Utilizing a third-order numerical scheme combined with wall-modeled large eddy simulation (WMLES) and the Ffowcs Williams-Hawkings (FW-H) acoustic analogy, the hydrodynamic and acoustic behaviors of an appended SUBOFF configuration are compared to those of a bare hull. A computational grid of 103 million cells resolves the intricate flow interactions, while 648 hydrophones positioned 500 diameters from the model capture far-field acoustic signatures. key results reveal that appendages significantly amplify hydrodynamic and acoustic disturbances. Flow separations and vortex shedding at appendage junctions elevate pressure-induced drag contributions, contrasting the viscous-dominated drag of the bare hull. The sail-hull interaction intensifies local surface pressure fluctuations, increasing power spectral density (PSD) amplitudes by up to an order of magnitude. In the far field, the appended SUBOFF generates sound pressure levels approximately 20 dB higher than the bare hull, with distinct dipole directivity patterns and peak noise levels (85.10 dB) observed on the central plane. Appendages also disrupt wake symmetry, introducing complex vortical structures such as horseshoe and necklace vortices. These findings demonstrate the critical influence of appendages on hydrodynamic and acoustic behavior, filling a gap in turbulence noise research for complex underwater geometries and providing a vital foundation for the noise reduction optimization of advanced underwater vehicles. Copyright © 2025, The Authors. All rights reserved.

关键词： Hydrodynamics

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Multi-Scale Semantic Communication for Object Detection: Single and Cross-Domain Scenarios

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IEEE Transactions on Wireless Communications 2025年

作者： Guo, Jie Yin, Hang Song, Bin Chi, Yuhao Zhang, Zhaoyang Yuen, Chau Niyato, Dusit Xidian University State Key Laboratory of Integrated Services Networks Xi’an710071 China Zhejiang University College of Information Science and Electronic Engineering Hangzhou310007 China School of Electrical and Electronics Engineering Nanyang Technological University 639798 Singapore Nanyang Technological University College of Computing and Data Science 639798 Singapore

With the rapid popularity of vision-driven communication applications, object detection has become one of the fundamental techniques for performing practical vision tasks. In traditional communication systems, images are compressed for transmission, reconstructed at the receiver, and then processed by existing object detection algorithms. However, transmitting large amounts of images consumes significant storage and communication resources. To address this challenge, a semantic communication-based image reconstruction scheme has been proposed for object detection, which transmits only the semantic information relevant to image reconstruction. However, this method is prone to losing key information, such as object position and texture details, leading to degraded object detection performance. Additionally, it is sensitive to environmental factors such as weather and lighting, resulting in poor adaptability across multiple scenarios. To address these issues, we propose a multiscale semantic communication framework for object detection that transmits only multi-scale semantic features relevant to the task and employs decoupling at the receiver to separate positional and classification information of target objects without requiring image reconstruction. To improve adaptability across multiple scenarios, we introduce a cross-domain object detection technique that ensures reliable object detection in new scenarios by optimizing the framework’s multi-scale semantic encoder through domain adversarial learning. Numerical results demonstrate that the proposed framework achieves mean average precision improvements of 15.4% ~ 38.5% over the traditional communication framework within low to medium signal-to-noise ratio regions in additive white Gaussian noise and Rayleigh fading channels. © 2002-2012 IEEE.

关键词： Fading channels

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Joint Beamforming and Offloading Design for Integrated Sensing, Communication, and Computation System

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IEEE Transactions on Vehicular Technology 2025年

作者： Liu, Peng Fei, Zesong Wang, Xinyi Zhou, Yiqing Zhang, Yan Liu, Fan Beijing Institute of Technology School of Information and Electronics Beijing100081 China Chinese Academy of Sciences University of Chinese Academy of Sciences State Key Laboratory of Processors Institute of Computing Technology Beijing100190 China Southeast University National Mobile Communications Research Laboratory School of Information Science and Engineering Nanjing210096 China

Mobile edge computing (MEC) is powerful in alleviating the heavy computing tasks in integrated sensing and communication (ISAC) systems. In this paper, we investigate joint beamforming and offloading design within a three-tier integrated sensing, communication, and computation (ISCC) framework comprising one cloud server, multiple mobile edge servers, and multiple terminals. While executing sensing tasks, the user terminals can optionally offload sensing data to either MEC servers or the cloud server. To minimize the execution latency, we jointly optimize the transmit beamforming vectors and offloading decision variables under the constraint of sensing performance. An alternating optimization algorithm based on fractional programming is proposed to tackle the non-convex problem. Simulation results demonstrate the superiority of the proposed mechanism in terms of convergence and task execution time reduction, compared with the state-of-the-art two-tier ISCC framework. © 1967-2012 IEEE.

关键词： Computation offloading

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APPLICATIONS OF HIGHER-ORDER SELF-ADJOINT SCHEMES TO PARTIAL-DIFFERENTIAL EQUATIONS

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COMPUTERS & MATHEMATICS WITH APPLICATIONS 1993年第3期26卷 15-26页

作者： ZHU, WJ QIN, MZ State Key Laboratory of Scientific and Engineering Computing Computing Center Academia Sinica Beijing 100080 China

In this paper, we apply the higher order self-adjoint schemes constructed in [1] to wave equation and heat equation to show these methods can also be used to solve partial differential equations to get higher order ac...

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VOLUME-PRESERVING SCHEMES AND NUMERICAL EXPERIMENTS

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COMPUTERS & MATHEMATICS WITH APPLICATIONS 1993年第4期26卷 33-42页

作者： QIN, MZ ZHU, WJ State Key Laboratory of Scientific and Engineering Computing Computing Center Academia Sinica Beijing 100080 China

In this paper, we discuss the conditions for Euler midpoint rule to be volume-preserving and present explicit volume preserving schemes. Some numerical experiments are done to test these schemes.

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An Adaptive Service Function Chains Mapping With Multi-Task Deep Reinforcement Learning

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IEEE Transactions on Network Science and engineering 2025年

作者： Wei, Wenting Wang, Qingyi Gu, Huaxi Zheng, Danyang Zhang, Ning Wu, Celimuge Xidian University State Key Laboratory of Integrated Service Networks Xi'an710071 China Southwest Jiaotong University School of Computing and Artificial Intelligence China University of Windsor Department of Electrical and Computer Engineering Canada University of Electro-Communications Meta-Networking Research Center Japan

Network function virtualization (NFV) facilitates different virtual network functions (VNF) to be dynamically chained in sequence to offer new services in a flexible, scalable, and cost-effective manner. Recent years have witnessed the increasing diverse service demands from the ever-increasing new applications, which has posed significant challenges to the efficient and sequential execution of VNFs to achieve specific objectives, especially under conditions of shared resources. To address these challenges, substantial efforts have been dedicated to enhancing resource utilization and minimizing the costs associated with service function chains (SFCs), while maintaining high quality of service. However, an overemphasis on cost reduction can sometimes result in network congestion, which ultimately degrades both network performance and service quality. Given the time-varying and unpredictable characteristics of SFCs, it is essential to leverage their temporal features, along with those of network states, for adaptive SFC mapping. In this paper, we introduce an adaptive online SFC mapping algorithm to reduce operational costs and alleviate network congestion. This is achieved through the adaptive allocation of VNFs and the control of traffic routing between them. Our approach incorporates multi-task deep reinforcement learning to manage the coexistence of multiple SFC requests with varying resource requirements. Specifically, we integrate a long short-term memory (LSTM) layer into our model to capture the temporal dynamics of network states and resource demands, thereby enabling more effective long-term planning. To address the issue of reward sparsity, we implement a hierarchical reward mechanism and reward shaping techniques. Experimental results demonstrate that our algorithm achieves near-optimal performance in optimizing service delay, bandwidth consumption, and network congestion, while also ensuring a high acceptance rate for user requests. © 2013 IEEE.

关键词： Network function virtualization

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