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Joint UAV trajectory and communication design with heterogeneous multi-agent reinforcement learning

science China(Information sciences) 2024年第3期67卷 225-245页

作者： Xuanhan ZHOU Jun XIONG Haitao ZHAO Xiaoran LIU Baoquan REN Xiaochen ZHANG Jibo WEI Hao YIN College of Electronic science and technology National University of Defense Technology Systems engineering institute Academy of Military Sciences PLA

Unmanned aerial vehicles(UAVs) are recognized as effective means for delivering emergency communication services when terrestrial infrastructures are unavailable. This paper investigates a multiUAV-assisted communication system, where we jointly optimize UAVs’ trajectories, user association, and ground users(GUs)’ transmit power to maximize a defined fairness-weighted throughput metric. Owing to the dynamic nature of UAVs, this problem has to be solved in real time. However, the problem’s non-convex and combinatorial attributes pose challenges for conventional optimization-based algorithms, particularly in scenarios without central controllers. To address this issue, we propose a multi-agent deep reinforcement learning(MADRL) approach to provide distributed and online solutions. In contrast to previous MADRLbased methods considering only UAV agents, we model UAVs and GUs as heterogeneous agents sharing a common objective. Specifically, UAVs are tasked with optimizing their trajectories, while GUs are responsible for selecting a UAV for association and determining a transmit power level. To learn policies for these heterogeneous agents, we design a heterogeneous coordinated QMIX(HC-QMIX) algorithm to train local Q-networks in a centralized manner. With these well-trained local Q-networks, UAVs and GUs can make individual decisions based on their local observations. Extensive simulation results demonstrate that the proposed algorithm outperforms state-of-the-art benchmarks in terms of total throughput and system fairness.

关键词： unmanned aerial vehicle (UAV) trajectory design resource allocation multi-agent deep reinforcement learning (MADRL) heterogeneous agents

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Analysis of phase preservation and interferometric offset test in sparse SAR imaging

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science China(Information sciences) 2024年第2期67卷 219-231页

作者： Zhongqiu XU Bingchen ZHANG Guangzuo LI Xueli ZHAN Yanfei BAO Yirong WU Key Laboratory of Spatial Information Processing and Application System technology Chinese Academy of Sciences Aerospace Information Research institute Chinese Academy of Sciences School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of Sciences pla academy of military sciences

Sparse synthetic aperture radar(SAR) imaging has emerged as a reliable microwave imaging scheme in the recent decade and excels in down-sampling reconstruction and full-sampling performance improvements such as noise, sidelobe, speckle, and ambiguity suppression. To utilize complex image products of sparse reconstruction for improvement in polarimetric, interferometric, and tomographic SAR imaging, it is necessary to evaluate the phase preservation of sparse SAR imaging. In this study, we first introduce the general alternating direction method of multipliers(ADMM) as the universal framework for sparse reconstruction algorithms and adopt chirp scaling algorithm(CSA)-based azimuth-range decouple operators to avoid expensive data storage and processing. Further, we theoretically analyze the phase preservation of the sparse reconstruction algorithm through a comparison with the reconstruction results of CSA. Finally,we conduct the interferometric offset test on the sparse reconstruction results of simulated and real Gaofen-3(GF-3) SAR data, demonstrating the phase-preserving ability of sparse methods.

关键词： sparse SAR imaging phase preservation interferometric offset test general ADMM azimuth-range decouple

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Degradable magnesium alloy suture promotes fibrocartilaginous interface regeneration in a rat rotator cuff transosseous repair model

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Journal of Magnesium and Alloys 2024年第1期12卷 384-393页

作者： Baoxiang Zhang Wen Zhang Fei Zhang Chao Ning Mingyang An Ke Yang Lili Tan Qiang Zhang Department of Sports Medicine Chinese PLA General HospitalBeijing 100853China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials science and engineering University of Science and Technology of ChinaShenyang 110016China Medical School of pla Beijing 100853China institute of Orthopedics Chinese PLA General HospitalBeijing Key Lab of Regenerative Medicine in OrthopedicsKey Lab of Musculoskeletal Trauma&War Injuries of Chinese PLABeijing 100853China

Despite transosseous rotator cuff tear repair using sutures is widely accepted for tendon-bone fixation,the fibrocartilaginous enthesis regeneration is still hardly achieved with the traditional *** the present work,degradable magnesium(Mg)alloy wire was applied to suture supraspinatus tendon in a rat acute rotator cuff tear model with Vicryl Plus 4±0 absorbable suture as *** shoulder joint humerus-supraspinatus tendon complex specimens were retrieved at 4,8,and 12 weeks after *** Mg alloy suture groups showed better biomechanical properties in terms of ultimate load to *** observation showed that hyperplastic response of the scar tissue at the tendon-bone interface is progressively alleviated over time in the both Mg alloy suture and Vicryl suture *** the histological analysis,for Mg alloy suture groups,chondrocytes appear to proliferate at 4 weeks postoperatively,and the tendon-bone interface showed an orderly structural transition zone at 8 weeks *** collagenous fiber tended to be aligned and the tendon-bone interlocking structures apparently formed,where transitional structure from unmineralized fibrocartilage to mineralized fibrocartilage was closer to the native fibrocartilaginous *** vivo degradation of the magnesium alloy wire was completed within 12 *** results indicated that Mg alloy wire was promising as degradable suture with the potential to promotes fibrocartilaginous interface regeneration in rotator cuff repair.

关键词： Rotator cuff repair Mg alloy wire Tendon-bone healing Fibrocartilaginous interface

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Average Secrecy Capacity of the Reconfigurable Intelligent Surface-Assisted Integrated Satellite Unmanned Aerial Vehicle Relay Networks

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Computer Modeling in engineering & sciences 2024年第2期138卷 1849-1864页

作者： Ping Li Kefeng Guo Feng Zhou XuelingWang Yuzhen Huang School of Information technology Yancheng Institute of TechnologyYancheng224051China School of Space Information Space Engineering UniversityBeijing101407China Space E-Star Communication technology Co. LtdNanjing210007China academy of military sciences of pla Beijing100097China

Integrated satellite unmanned aerial vehicle relay networks(ISUAVRNs)have become a prominent topic in recent *** paper investigates the average secrecy capacity(ASC)for reconfigurable intelligent surface(RIS)-enabled ***,an eve is considered to intercept the legitimate information from the considered secrecy ***,we get detailed expressions for the ASC of the regarded secrecy system with the aid of the reconfigurable ***,to gain insightful results of the major parameters on the ASC in high signalto-noise ratio regime,the approximate investigations are further gotten,which give an efficient method to value the secrecy *** last,some representative computer results are obtained to prove the theoretical findings.

关键词： Integrated satellite unmanned aerial vehicle relay networks reconfigurable intelligent surface average secrecy capacity(ASC) asymptotic ASC

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Discovering the ultralow thermal conductive A_(2)B_(2)O_(7)-type high-entropy oxides through the hybrid knowle dge-assiste d data-driven machine learning

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Journal of Materials science & technology 2024年第1期168卷 131-142页

作者： Ying Zhang Ke Ren William Yi Wang Xingyu Gao Ruihao Yuan Jun Wang Yiguang Wang Haifeng Song Xiubing Liang Jinshan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Innovation Center NPU ChongqingChongqing 401135China institute of Advanced Structure technology Beijing Institute of TechnologyHaidian DistrictBeijing 100081China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Defense Innovation institute Academy of Military Sciences of the PLA of ChinaBeijing 100071China

Lattice engineering and distortion have been considered one kind of effective strategies for discovering advanced *** instinct chemical flexibility of high-entropy oxides(HEOs)motivates/accelerates to tailor the target properties through phase transformations and lattice ***,a hybrid knowledge-assisted data-driven machine learning(ML)strategy is utilized to discover the A_(2)B_(2)O_(7)-type HEOs with low thermal conductivity(κ)through 17 rare-earth(RE=Sc,Y,La-Lu)solutes optimized A-site.A designing routine integrating the ML and high throughput first principles has been proposed to predict the key physical parameter(KPPs)correlated to the targetedκof advanced *** the smart-designed 6188(5RE_(0.2))_(2)Zr_(2)O_(7)HEOs,the best candidates are addressed and validated by the princi-ples of severe lattice distortion and local phase transformation,which effectively reduceκby the strong multi-phonon scattering and weak interatomic ***,(Sc_(0.2)Y_(0.2)La_(0.2)Ce_(0.2)Pr_(0.2))_(2)Zr_(2)O_(7)with predictedκbelow 1.59 Wm^(−1)K^(−1)is selected to be verified,which matches well with the ex-perimentalκ=1.69 Wm^(−1)K^(−1)at 300 K and could be further decreased to 0.14 Wm^(−1)K^(−1)at 1473 ***,the coupling effects of lattice vibrations and charges on heat transfer are revealed by the cross-validations of various models,indicating that the weak bonds with low electronegativity and few bond-ing charge density and the lattice distortion(r∗)identified by cation radius ratio(r A/r B)should be the KPPs to decreaseκ*** work supports an intelligent designing strategy with limited atomic and electronic KPPs to accelerate the development of advanced multi-component HEOs with proper-ties/performance at multi-scales.

关键词： High-entropy oxides Thermal conductivity Pyrochlore Key physical parameter First-Principles

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Research advances in smart responsive-hydrogel dressings with potential clinical diabetic wound healing properties

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military Medical Research 2024年第4期11卷 543-566页

作者： Ying Chen Xing Wang Sheng Tao Qi Wang Pan-Qin Ma Zi-Biao Li Yun-Long Wu Da-Wei Li Fujian Provincial Key Laboratory of Innovative Drug Target Research and State Key Laboratory of Cellular Stress Biology School of Pharmaceutical SciencesXiamen UniversityXiamen 361102FujianChina Beijing National Laboratory for Molecular sciences Institute of ChemistryChinese Academy of SciencesBeijing 100090China University of Chinese academy of sciences Beijing 100049China Senior Department of Orthopedics the Fourth Medical Center of Chinese PLA General HospitalBeijing 100091China institute of Materials Research and engineering A*STAR(Agency for ScienceTechnology and Research)Singapore 138634Singapore

The treatment of chronic and non-healing wounds in diabetic patients remains a major medical *** reports have shown that hydrogel wound dressings might be an effective strategy for treating diabetic wounds due to their excellent hydrophilicity,good drug-loading ability and sustained drug release *** a typical example,hyaluronic acid dressing(Healoderm)has been demonstrated in clinical trials to improve wound-healing efficiency and healing rates for diabetic foot ***,the drug release and degradation behavior of clinically-used hydrogel wound dressings cannot be adjusted according to the wound *** to the intricacy of diabetic wounds,antibiotics and other medications are frequently combined with hydrogel dressings in clinical practice,although these medications are easily hindered by the hostile *** this case,scientists have created responsive-hydrogel dressings based on the microenvironment features of diabetic wounds(such as high glucose and low pH)or combined with external stimuli(such as light or magnetic field)to achieve controllable drug release,gel degradation,and microenvironment improvements in order to overcome these clinical *** responsive-hydrogel dressings are anticipated to play a significant role in diabetic therapeutic wound ***,we review recent advances on responsive-hydrogel dressings towards diabetic wound healing,with focus on hydrogel structure design,the principle of responsiveness,and the behavior of *** but not least,the advantages and limitations of these responsive-hydrogels in clinical applications will also be *** hope that this review will contribute to furthering progress on hydrogels as an improved dressing for diabetic wound healing and practical clinical application.

关键词： Responsive-hydrogel Diabetic wound Anti-inflammation Tissue remodeling

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High-Order Characteristic Modes Suppression for Cross-Band Decoupling in Shared-Aperture Antenna Array

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Chinese Journal of Electronics 2022年第6期31卷 1121-1128页

作者： LU Xiaochi CHEN Yikai SHEN Tongsheng GUO Shaojun ZOU Chunrong YANG Shiwen School of Electronic science and engineering University of Electronic Science and Technology of China National Innovation institute of Defense technology Academy of Military Sciences PLA China

In dual-band shared-aperture base station antennas, the secondary radiation(SR) field caused by cross-band couplings always leads to radiation pattern distortion. In this work, the SR field caused by the coupling is attributed to the excitation of the target highorder modes from the perspective of the characteristic mode. To effectively suppress the target modes, L-shaped slots are proposed to load the arms of the radiator and altering the current paths. As compared with conventional dipoles without L-shaped slots, the proposed antenna generates less SR field. Therefore, the radiation pattern of the high-band antennas keeps stable in a dual-band shared-aperture antenna array environment. Prototype of a dual-band antenna array consisting of the proposed lowband(LB) antenna and a 4 × 4 high-band(HB) antenna array is fabricated. Simulated and measured results show that the designed dual-band array operates at both 0.74–0.82 GHz and 3.30–3.80 GHz. The experimental results verify that the cross-band decoupling has been achieved with the high-order mode suppression.

关键词： Characteristic modes (CMs) Base station antenna Shared-aperture antenna High-order modes suppression

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Relationships between distribution characteristics of ceramic fragments and anti-penetration performance of ceramic composite bulletproof insert plates

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Defence technology（防务技术） 2023年第1期19卷 103-110页

作者： Wen-hao Yu Wei-ping Li Yi-fan Shangguan Xin-yang Ji Tian Ma Guo-qing Wu School of Materials science and engineering Beihang UniversityBeijing100191China institute of quartermaster engineering technology of pla academy of military science Beijing100010China China Linyi High-tech Zone Shuanghang Material technology Co. Ltd.Linyi276000China

Through quantitative statistics and morphological characterization of ceramic fragments for ceramic composite bulletproof insert plates(CCBIPs),distribution characteristics of ceramic fragments within a specific size range were analyzed for different Armor Piercing Incendiary(API)and shot *** quantitatively evaluate the effect of energy absorption for ceramic plates,a model of energy absorption during penetration for CCBIPs was established based on statistics of the size distribution of ceramic fragments(SDCF).Variation in the SDCF and its influence on energy absorption for CCBIPs were *** results indicate that the distribution feature of ceramic fragments in the range of 0.25-2.25 mm is Gaussian *** with Type 56 of API(56-API),ceramic fragments formed by 53-API with higher kinetic energy possess more quantity and more concentrated distribution,whose average equivalence size decreases by 6.5%,corresponding to increasing by 83.9%of estimated energy ***,the ability of CCBIPs to resist the third shot is significantly weakened,whose estimated energy absorption decreases by 58.8%compared with the first *** concentrated distribution and fewer fragments are formed after the third shot,the average equivalence size of ceramic fragments increases by 6.9%,which may attribute to the micro-cracks induced by the previous two shots.

关键词： Bulletproof insert plate Ceramic fragment Statistic Energy absorption Anti-penetration performance

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Simulation and experiment of six-bed PSA process for air separation with rotating distribution valve

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Chinese Journal of Chemical engineering 2022年第2期35卷 329-337页

作者： Tao Tian Yayan Wang Bing Liu Zhaoyang Ding Xinxi Xu Meisheng Shi Jun Ma Yanjun Zhang Donghui Zhang institute of Medical Support technology Academy of System Engineering of Academy of Military Science of Chinese PLATianjin 300161China School of Chemical engineering and technology Tianjin UniversityTianjin 300072China

In this work,a six-bed pressure swing adsorption(PSA)process was investigated to produce medical oxygen from air,which uses the combination of six-way rotating distribution valve and PSA and has the main advantage of effectively saving space compared to the traditional two-bed or four-bed PSA process and can obtain greater *** mathematical model of adsorption beds was developed based on the separation mechanism and the interaction among different ***,a pilot-scale device has been constructed to verify the accuracy of mathematical model by *** oxygen product conformed to the medical standard(>93%(vol))with a recovery of over 57%.Some related parameters were also discussed in detail,such as step time,ratio of length to the diameter,flow rate of product.

关键词： Pressure swing adsorption Air separation Mathematical modeling Rotating distribution valve

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Dynamic Camouflage Characteristics of a Thermal Infrared Film Inspired by Honeycomb Structure

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Journal of Bionic engineering 2022年第2期19卷 458-470页

作者： Lujia Li Huanhuan Li Gang Kou Dafeng Yang Wei Hu Jinghui Peng Songjing Li Department of Fluid Control and Automation Harbin Institute of TechnologyHarbin 150001China Research institute for National Defense engineering of academy of military science pla China Luoyang 471023China

Thermal infrared camouflage technology has attracted increasing attention with the progress of infrared surveillance *** by honeycombs,a thermal infrared camouflage film with honeycomb sandwich structure based on fluid and temperature control is proposed to cloak objects and display false targets in the thermal infrared *** structure and manufacturing method of the film are introduced,and the fluid and temperature control system is established and tested to explore the thermal infrared characteristics of the film composed of different thermal *** camouflage performance of the film is intuitively displayed through the temperature frequency histograms of the infrared images photographed by an infrared *** temperature control accuracy of the thermal infrared camouflage system and the dynamic camouflage response of the film are evaluated by the temperature distribution map of each pixel in infrared images and the salient degree ***,the influential factors on the camouflage responding time are investigated,including the heating and cooling time of the liquid,the flow rate of pumps inside the driving module,and the energy loss along the liquid *** application of displaying false target is also introduced and *** results show that the camouflage film has a well camouflage effect and a wide adjustment temperature range,showing promise for a broad range of potential applications,such as counter-surveillance,thermal control and heat shielding.

关键词： Bioinspiration Film Thermal camoufage Honeycomb structure Temperature control

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