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Two efficient beamforming methods for hybrid IRS-aided AF relay wireless networks

science China(information sciences) 2025年第4期68卷 363-379页

作者： Xuehui WANG Qingbo LI Wen ZHU Feng SHU Mengxing HUANG Fuhui ZHOU Riqing CHEN Cunhua PAN Yongpeng WU Jiangzhou WANG School of Mathematics and Statistics Hainan Normal University Key Laboratory of Data Science and Smart Education Ministry of Education Hainan Normal University School of Information and Communication Engineering Hainan University Collaborative Innovation Center of Information Technology Hainan University School of Electronic and Optical Engineering Nanjing University of Science and Technology College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Digital Fujian Institute of Big Data for Agriculture Fujian Agriculture and Forestry University National Mobile Communications Research Laboratory Southeast University Shanghai Key Laboratory of Navigation and Location Based Services Shanghai Jiao Tong University School of Engineering University of Kent

Owing to its ability to mitigate the double-fading effect by amplifying the reflected signal, the active intelligent reflecting surface(IRS) has garnered significant attention. In this paper, an amplify-and-forward(AF) relay network assisted by a hybrid IRS consisting of both passive and active units is developed. A signal-to-noise ratio(SNR) maximization problem is formulated, where the AF relay beamforming matrix and the hybrid IRS reflecting coefficient matrices for two-time slots need to be optimized. To address the SNR maximization problem, this paper proposes both a high-performance(HP) method and a low-complexity(LC) method. The HP method is based on the semidefinite relaxation and fractional programming(SDR-FP)algorithm, with rank-1 solutions obtained through Gaussian randomization. For the LC method, the amplification coefficient of each active IRS element is assumed to be equal. The SNR maximization problem is then addressed using the whitening filter,generalized power iteration, and generalized Rayleigh-Ritz(WF-GPI-GRR) approach. Simulation results show that compared with the benchmarks, such as the passive IRS-aided AF relay network, the proposed HP-SDR-FP and WF-GPI-GRR methods achieve significant rate improvements. In particular, the HP-SDR-FP and WF-GPI-GRR methods yield more than a 135.0%rate gain when the transmit power Ps of the source is 10 dBm. Furthermore, the proposed HP-SDR-FP method outperforms the WF-GPI-GRR method in terms of rate performance.

关键词： double-fading intelligent reflecting surface active elements passive elements hybrid IRS AF relay

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A spawning particle filter for defocused moving target detection in GNSS-based passive radar

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Journal of systems engineering and Electronics 2023年第5期34卷 1085-1100页

作者： ZENG Hongcheng DENG Jiadong WANG Pengbo ZHOU Xinkai YANG Wei CHEN Jie School of Electronic and Information Engineering Beihang UniversityBeijing 100191China National Key Laboratory of Science and Technology on Space Microwave China Academy of Space TechnologyXi’an 710000China

Global Navigation Satellite System(GNSS)-based passive radar(GBPR)has been widely used in remote sensing ***,for moving target detection(MTD),the quadratic phase error(QPE)introduced by the non-cooperative target motion is usually difficult to be compensated,as the low power level of the GBPR echo signal renders the estimation of the Doppler rate less ***,the moving target in GBPR image is usually defocused,which aggravates the difficulty of target detection even *** this paper,a spawning particle filter(SPF)is proposed for defocused ***,the measurement model and the likelihood ratio function(LRF)of the defocused point-like target image are ***,a spawning particle set is generated for subsequent target detection,with reference to traditional particles in particle filter(PF)as their *** that,based on the PF estimator,the SPF algorithm and its sequential Monte Carlo(SMC)implementation are proposed with a novel amplitude estimation method to decrease the target state ***,the effectiveness of the proposed SPF is demonstrated by numerical simulations and pre-liminary experimental results,showing that the target range and Doppler can be estimated accurately.

关键词： Global Navigation Satellite System(GNSS)-based passive radar(GBPR) defocused target moving target detec-tion(MTD) likelihood ratio function(LRF) spawning particle fil-ter(SPF)

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MATD3-Based End-Edge Collaborative Resource Optimization for NOMA-Assisted Industrial Wireless Networks

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Computers, Materials & Continua 2025年第2期82卷 3203-3222页

作者： Ru Hao Chi Xu Jing Liu College of Information Engineering Shenyang University of Chemical TechnologyShenyang110142China State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang110016China Key Laboratory of Networked Control Systems Chinese Academy of SciencesShenyang110016China

Non-orthogonal multiple access (NOMA) technology has recently been widely integrated into multi-access edge computing (MEC) to support task offloading in industrial wireless networks (IWNs) with limited radio resources. This paper minimizes the system overhead regarding task processing delay and energy consumption for the IWN with hybrid NOMA and orthogonal multiple access (OMA) schemes. Specifically, we formulate the system overhead minimization (SOM) problem by considering the limited computation and communication resources and NOMA efficiency. To solve the complex mixed-integer nonconvex problem, we combine the multi-agent twin delayed deep deterministic policy gradient (MATD3) and convex optimization, namely MATD3-CO, for iterative optimization. Specifically, we first decouple SOM into two sub-problems, i.e., joint sub-channel allocation and task offloading sub-problem, and computation resource allocation sub-problem. Then, we propose MATD3 to optimize the sub-channel allocation and task offloading ratio, and employ the convex optimization to allocate the computation resource with a closed-form expression derived by the Karush-Kuhn-Tucker (KKT) conditions. The solution is obtained by iteratively solving these two sub-problems. The experimental results indicate that the MATD3-CO scheme, when compared to the benchmark schemes, significantly decreases system overhead with respect to both delay and energy consumption.

关键词： Industrial wireless networks(IWNs) multi-access edge computing(MEC) non-orthogonal multiple access(NOMA) task offloading resource allocation

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MLP-Mixer based Masked Auto encoders Are Effective, Explainable and Robust for Time Series Anomaly Detection 51st

MLP-Mixer based Masked Auto encoders Are Effective, Explaina...

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51st International Conference on Very Large Data Bases, VLDB 2025

作者： Tang, Qideng Dai, Chaofan Wu, Yahui Zhou, Haohao National Key Laboratory of Information Systems Engineering National University of Defense Technology China National University of Defense Technology China

Time series anomaly detection remains one of the most active research areas in data mining due to its wide range of real-world applications. In recent years, numerous deep learning-based methods have been proposed for this task. However, deep learning-based methods fail to detect subsequence anomalies with long durations, lack explain ability, and are vulnerable to training set contamination. This paper addresses these issues by proposing a novel deep learning framework for effective, explainable, and robust time series anomaly detection. Our framework, MMA, incorporates the MLP-Mixer backbone with a Masked Auto encoder-based anomaly detection approach to allow for a significantly larger input window size (10 to 20 times larger than the input window sizes of current models). This larger input window enables our model to detect challenging subsequence anomalies. Meanwhile, a contrast learning module is proposed to aid in detecting subtle anomalies that fail to be identified by residual errors. Furthermore, a dynamic anomaly filtering method is introduced to mitigate the impact of subsequence anomalies on the reconstruction of surrounding normal regions to reduce false alarms. Extensive experiments on univariate and multivariate time series datasets demonstrate that our proposed framework significantly outperforms state-of-the-art methods across rigorous evaluation metrics. Additionally, MMA has a strong ability to reconstruct potential normal patterns in anomalous regions, providing high levels of explain ability. Moreover, MMA demonstrates high robustness to various types of training set pollution. © 2025, VLDB Endowment, All rights reserved.

关键词： Mixers (machinery)

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Multiple effects of polydopamine nanoparticles on Cu^(2+)-mediated Alzheimer's β-amyloid aggregation

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Chinese Journal of Chemical engineering 2023年第2期54卷 144-152页

作者： Xueqing Chen Weiqun Gao Yan Sun Xiaoyan Dong Department of Biochemical Engineering School of Chemical Engineering and Technology and Key Laboratory of Systems Bioengineering and Frontiers Science Center for Synthetic Biology(Ministry of Education)Tianjin UniversityTianjin 300350China

Deposition of β-amyloid protein(Aβ) is the main hallmark of Alzheimer's disease(AD), and it has been well recognized that Cu^(2+)-mediated Aβ aggregation plays a crucial role in AD pathological ***^(2+)binding to Aβ can promote the production of reactive oxygen species(ROS) through Fenton-like reactions and produce more toxic Aβ-Cu^(2+)species under Cu^(2+)stimulation. Thus, the development of nanomaterials that can inhibit Cu^(2+)-mediated Aβ aggregation and degrade Aβ-Cu^(2+)complexes is considered an effective strategy for the prevention and treatment of AD. In this study, polydopamine nanoparticles(PDA NPs) were prepared and the results reveal that PDA NPs potently inhibit Cu^(2+)-mediated Aβaggregation and effectively reduce the formation of Aβ-Cu^(2+)complexes. In vitro experiments show that PDA NPs efficiently eliminate ROS generation catalyzed by Cu^(2+)or Aβ-Cu^(2+)complexes, thus rescuing cultured cells by reducing intracellular ROS levels. More importantly, PDA NPs can depolymerize Aβ-Cu^(2+)complexes, and the degradation of Aβ-Cu^(2+)complexes is promoted by near-infrared light irradiation due to their high photothermal conversion ability. In vivo studies reveal that PDA NPs significantly reduce the deposition of Aβ plaques in the presence of Cu^(2+)and extend the lifespan of AD nematodes from 11 to 14 d. Thus, the PDA NPs developed herein are multifunctional against Cu^(2+)-mediated Aβ aggregation for the potential prevention and treatment of AD.

关键词： Protein Aggregation Nanoparticles Photothermal therapy Reactive oxygen species Cu^(2+)chelator

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A new method for fast spectral demodulation of wide-measurement range optical fiber torsion sensor

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IEEE Sensors Journal 2025年第11期25卷 19258-19267页

作者： Cao, Jiaqi Guo, Yuying Gao, Wei Wang, Xin Lou, Shuqin Sheng, Xinzhi Beijing Jiaotong University School of Electronic and Information Engineering Key Laboratory of Communication and Information Systems Beijing Municipal Commission of Education Beijing100044 China Beijing Jiaotong University School of Science Beijing100044 China

We present a new method using the combination of the Fast Fourier transform (FFT)-support vector regression (SVR) algorithm for fast spectral demodulation of an optical fiber torsion sensor based on Sagnac interferometer. Experimental results demonstrate that with the aid of the FFT-SVR algorithm, the full torsion angle range from -360° to 360° can be predicted with a mean absolute error of 3.05° and determination coefficient of 0.9995. More importantly, compared with the SVR algorithm-only demodulation, the FFT-SVR algorithm can efficiently decrease the number of features from 2001 to 25 and thus the running time can be decreased from 0.005 s to 0.002 s, which makes the running time a 60% reduction. Additionally, the spectrum scanning time can be decreased from 1.6 s to 1 s, thereby resulting in a 37.5% decrease in the spectrum scanning time. Compared with other FFT-based machine learning methods, the FFT-SVR algorithm has high measurement accuracy and short running time, which greatly improves the measuring speed of optical fiber torsion and has great potential for application in many fields, such as the attitude sensing, shape measurement and automatic control of robotic manipulators. © 2025 IEEE.

关键词： Optical fibers

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Facile purification and immobilization of organophosphorus hydrolase on protein-inorganic hybrid phosphate nanosheets

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Chinese Journal of Chemical engineering 2023年第4期56卷 119-125页

作者： Zhenfu Wang Jie Gao Qinghong Shi Xiaoyan Dong Yan Sun Department of Biochemical Engineering School of Chemical Engineering and Technology and Key Laboratory of Systems Bioengineering and Frontiers Science Center for Synthetic Biology(Ministry of Education)Tianjin UniversityTianjin 300350China

Oriented immobilization of enzymes helps to maintain their native structure and proper orientation for high-performance engineering to meet extensive biocatalysis ***,the supporting materials used for orientated immobilization are usually costly or complicated in preparation,affecting their practical *** this work,a facile purification and immobilization method was proposed for enzyme immobilization based on organic-inorganic hybrid calcium phosphate nanocrystal(Ca Ps)induced by Cu^(2+) modified bovine serum albumin(BSA-Cu).Then,the as-prepared hybrid calcium phosphate nanosheet,BSA-Cu@Ca Ps,was utilized for one-pot purification and immobilization of His-tagged organophosphorus hydrolase(OPH)by metal-affinity binding to the incorporated ***-Cu@Ca PsOPH exhibited enhanced p H stability and thermal stability compared to the free ***,BSA-Cu@Ca Ps-OPH could retain more than 75%and 56%of initial activity after reuse 5 and 10 times,*** results demonstrated that this facile strategy was promising for the effective biodegradation of organophosphorus pesticides with the immobilized enzyme.

关键词： Calcium phosphate nanocrystal(CaPs) Biomimetic mineralization Organophosphorus hydrolase(OPH) Oriented immobilization Hydrolysis Methyl parathion

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VMMAO-YOLO:an ultra-lightweight and scale-aware detector for real-time defect detection of avionics thermistor wire solder joints

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Frontiers of Mechanical engineering 2024年第3期19卷 77-92页

作者： Xiaoqi YANG Xingyue LIU Qian WU Guojun WEN Shuang MEI Guanglan LIAO Tielin SHI School of Mechanical Engineering and Electronic Information China University of GeosciencesWuhan 430074China State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

The quality of the exposed avionics solder joints has a significant impact on the stable operation of the inorbit ***,the previously reported inspection methods for multi-scale solder joint defects generally suffer low accuracy and slow detection ***,a novel real-time detector VMMAO-YOLO is demonstrated based on variable multi-scale concurrency and multi-depth aggregation network(VMMANet)backbone and“one-stop”global information gather-distribute(OS-GD)*** with infrared thermography technology,it can achieve fast and high-precision detection of both internal and external solder joint ***,VMMANet is designed for efficient multi-scale feature extraction,which mainly comprises variable multi-scale feature concurrency(VMC)and multi-depth feature aggregation-alignment(MAA)*** can extract multi-scale features via multiple fix-sized and deformable convolutions,while MAA can aggregate and align multi-depth features on the same order for feature *** allows the low-level features with more spatial details to be transmitted in depth-wise,enabling the deeper network to selectively utilize the preceding inference *** VMMANet replaces inefficient highdensity deep convolution by increasing the width of intermediate feature levels,leading to a salient decline in *** OS-GD is developed for efficacious feature extraction,aggregation and distribution,further enhancing the global information gather and deployment capability of the *** a self-made solder joint image data set,the VMMAOYOLO achieves a mean average precision mAP@0.5 of 91.6%,surpassing all the mainstream YOLO-series ***,the VMMAO-YOLO has a body size of merely 19.3 MB and a detection speed up to 119 frame per second,far superior to the prevalent YOLO-series detectors.

关键词： defect detection of solder joints VMMAO-YOLO ultra-lightweight and high-performance multiscale feature extraction VMC and MAA modules OS-GD

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a-Synuclein: A fusion chaperone significantly boosting the enzymaticperformance of PET hydrolase

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Chinese Journal of Chemical engineering 2023年第12期64卷 18-25页

作者： Renwen Tian Yan Sun Department of Biochemical Engineering School of Chemical Engineering and Technology and Key Laboratory of Systems Bioengineering and Frontiers Science Center for Synthetic Biology(Ministry of Education)Tianjin UniversityTianjin 300350China

Extensive use of polyethylene terephthalate (PET) has brought about global environmental problems. Arecently reported PET hydrolase (PETase) discovered from Ideonella sakaiensis showed high potentialfor degrading PET at moderate temperatures, but its activity and stability need further improvementfor practical applications. Herein, we proposed to use a-synuclein (aS) as a fusion chaperone and createdsix PETase-aS fusion enzymes with linkers of different types and lengths. All the fusion enzymes exhibited improved enzymatic performance, presenting 1.5 to 2.6-fold higher activity towards bis-2(hydroxyethyl) terephthalate than PETase, as well as significantly increased stabilities. Fluorescencespectroscopy indicated that the chaperone fusion tightened the overall conformation and resulted inthe opening of the substrate binding pocket, which led to the improved thermal stability and catalyticactivity of the fusion enzymes. Remarkably, one of the fusion proteins, PETase-[(GS)(EK)]10-aS, showed3.2 to 5.1 times higher PET degradation capability than PETase. The significantly boosted PET degradationperformance was not only attributed to the enhanced enzymatic activity and stability, but also possiblydue to the binding affinity of the fused aS domain for PET. These findings demonstrated that aS was aneffective fusion chaperone for significantly enhancing the enzymatic performance of PETase.

关键词： PET hydrolase a-Synuclein Fusion enzyme Stability Pollution Degradation

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Human activities rather than climate dominated the grassland net primary production in the three basins of the Hexi Corridor,North-Western China

River

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River 2023年第2期2卷 210-221页

作者： Yutao Wang Tianbao Dou Research Center Gansu Institute of Science and Technology InformationGansu Provincial Key Laboratory of Science and Technology EvaluationLanzhouChina Key Laboratory of Western China's Environmental Systems College of Earth and Environmental ScienceLanzhou UniversityLanzhouChina

Actual net primary production(ANPP)is affected by both natural conditions and human activities in many areas,while the contributions of these factors to NPP remain unknown because it is difficult to isolate their *** knowledge gap hinders our implementation of environmental protection and *** this study,we selected three basins of the Hexi Corridor,North-western China,as the study *** on the monthly growth of grassland and field observations,we identified the undisturbed grids and then calculated the potential net primary productivity(PNPP)of these *** the Carnegie-Ames-Stanford-Approach(CASA)model,we calculated the ANPP in these *** influence of human activities on NPP(HNPP)was then calculated as the difference between ANPP and *** results showed that from 2001 to 2017,the mean grassland HNPP was−236.25 gC m^(−2) a^(−1).The area with a relative contribution index(RCI)of human activity greater than 0.5 accounted for more than 50%of the total,indicating that human activities were a dominant factor in the NPP *** the implementation of ecological governance projects in the Hexi Corridor in 2006,HNPP exhibited a negative weakening rate of 2.79 gC m^(−2) a^(−1)(p<0.05),and the RCI decreased from 0.708 at the beginning of the study period to 0.522 at the end(p<0.01),indicating that reducing human interference with nature was an effective measure for ecological *** on these findings,we concluded that the changes in NPP in the three basins of the Hexi Corridor was dominated by human *** results suggest that future studies pertaining to the response of NPP to climate change should consider the impact of human activities in semi-arid regions.

关键词： coincidence ratio Hexi corridor human influence net primary productivity potential NPP

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