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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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Influence of pore structure heterogeneity on channeling channels during hot water flooding in heavy oil reservoir based on CT scanning

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Petroleum Science 2024年第4期21卷 2407-2419页

作者： Qing-jun Du hao-Yu Zheng Jian Hou Yong-Ge Liu Jian-Fang Sun Dong Zhao State Key Laboratory of Deep Oil and Gas China University of Petroleum (East China) School of Petroleum Engineering China University of Petroleum (East China) Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and Technology Petroleum Exploration and Production Research Institute

Hot water flooding is an effective way to develop heavy oil reservoirs. However, local channeling channels may form, possibly leading to a low thermal utilization efficiency and high water cut in the reservoir. The pore structure heterogeneity is an important factor in forming these channels. This study proposes a method that mixes quartz sand with different particle sizes to prepare weakly heterogeneous and strongly heterogeneous models through which hot water flooding experiments are *** the experiments, computer tomography(CT) scanning identifies the pore structure and micro remaining oil saturation distribution to analyze the influence of the pore structure heterogeneity on the channeling channels. The oil saturation reduction and average pore size are divided into three levels to quantitatively describe the relationship between the channeling channel distribution and pore structure heterogeneity. The zone where oil saturation reduction exceeds 20% is defined as a channeling *** scanning area is divided into 180 equally sized zones based on the CT scanning images, and threedimensional(3D) distributions of the channeling channels are developed. Four micro remaining oil distribution patterns are proposed, and the morphology characteristics of micro remaining oil inside and outside the channeling channels are analyzed. The results show that hot water flooding is more balanced in the weakly heterogeneous model, and the oil saturation decreases by more than 20% in most zones without narrow channeling channels forming. In the strongly heterogeneous model, hot water flooding is unbalanced, and three narrow channeling channels of different lengths form. In the weakly heterogeneous model, the oil saturation reduction is greater in zones with larger pores. The distribution range of the average pore size is larger in the strongly heterogeneous model. The network remaining oil inside the channeling channels is less than outside the channeling channels,

关键词： Heavy oil Hot water flooding Pore structure Channeling channels CT scanning

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Insight into Lithium–sulfur batteries performance enhancement: from metal nanoparticles to metal nanoclusters to single metal atoms

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Tungsten 2024年第3期6卷 504-521页

作者： Shuang Ma Qing-ling Ruan Xue-Cheng Liu Gui-jun Zhu Die Yuan ling-Qiao Hu Yu-Mei Huang Xing-Xing Gu Chongqing Key Laboratory of Catalysis and New Environmental Materials College of Environment and Resources Chongqing Technology and Business University National Research Base of Intelligent Manufacturing Service Chongqing Technology and Business University

Lithium-sulfur(Li-S) batteries have attracted much attention and developed rapidly in recent years due to their high energy density,low cost,and ***,its commercialization process still encounters various *** them,the sulfur cathode is easy to dissolve and shuttle,resulting in the loss of active substances and the severe growth of lithium anode dendrites,which is one of the biggest *** the redox conversion kinetics of sulfur cathode is expected to fundamentally alleviate the shuttle phenomenon of poly ***,this paper reviews the effects of metal nanoparticles to metal nanoclusters to metal single-atom catalysts on improving the redox of Li-S batteries,to let researchers better understand the size effect on the kinetics of sulfur cathodes in Li-S batteries,which will provide important guidance for the future large-scale commercialization of Li-S batteries.

关键词： Lithium–sulfur batteries Metal nanoparticles Metal nanoclusters Metal single atoms Size effects

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Clinical efficacy and pathological outcomes of transanal endoscopic intersphincteric resection for low rectal cancer

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 933-944页

作者： Zhi-Wen Xu Jing-Tao Zhu hao-Yu Bai Xue-jun Yu Qing-Qi Hong jun You Department of Gastrointestinal Oncology Surgery The First Affiliated Hospital of Xiamen UniversitySchool of MedicineXiamen UniversityXiamen 361000Fujian ProvinceChina

BACKGROUND Transanal endoscopic intersphincteric resection(ISR)surgery currently lacks sufficient clinical research and *** To investigate the clinical effectiveness of transanal endoscopic ISR,in order to promote the clinical application and development of this *** This study utilized a retrospective case series *** and pathological data of patients with lower rectal cancer who underwent transanal endoscopic ISR at the First Affiliated Hospital of Xiamen University between May 2018 and May 2023 were *** patients underwent transanal endoscopic ISR as the surgical *** conducted this study to determine the perioperative recovery status,postoperative complications,and pathological specimen charac-teristics of this group of *** This study included 45 eligible patients,with no perioperative *** overall incidence of early complications was 22.22%,with a rate of 4.44%for Clavien-Dindo grade≥III *** patients(4.4%)developed anastomotic leakage after surgery,including one case of grade A and one case of grade *** pathological examination confirmed negative circumferential resection margins and distal resection margins in all *** mean distance between the tumor lower margin and distal resection margin was found to be 2.30±0.62 *** transanal endoscopic ISR procedure consistently yielded high quality pathological *** Transanal endoscopic ISR is safe,feasible,and provides a clear anatomical *** is associated with a low incidence of postoperative complications and favorable pathological outcomes,making it worth further research and application.

关键词： Intersphincteric resection Transanal Rectal cancer Complications Endoscopic

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Prospective life cycle assessment of CO2 conversion by photocatalytic reaction

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Green Chemical Engineering 2024年第3期5卷 383-389页

作者： jun-Qi Wang Xiang-jun Liu Jing-Jing Ma Shuai Zhang hao-Ran Liu Yong-Li Dong Qing-Yuan Yang School of Human Settlements and Civil Engineering Xi'an Jiaotong University School of Chemical Engineering and Technology Xi'an Jiaotong University

CO2conversion is gradually seen as a better way for society to effectively use carbon sources and avoid climate crisis associated with fossil CO2emissions. And the decision to deploy CO2technology scale should be relied on its environmental impact. In this work, life cycle assessment model evaluates the environmental performance of CO2conversion by photocatalytic reaction process with two different catalysts（NiAl-LDH and Co-ZIF-9）. Six impact categories considered in this analysis, including climate change, acidification potential, depletion of abiotic resources, eutrophication potential, ozone layer depletion potential, and photochemical oxidation potential. Results indicated that CO2conversion with Co-ZIF-9 photocatalyst has a better environmental impact than the NiAl-LDH photocatalyst route. Moreover, the Co-ZIF-9 catalyst scenario also has a lower total environmental burden than the conventional CO production route. Sensitivity analysis shows that recycle performance of the catalyst is highly sensitive to the production process in two scenarios. This study could provide a framework for robust decisions in CO2conversion by photocatalytic reaction, which is useful for policymakers to decide the feasibility of industrialization.

关键词： Life cycle assessment (LCA) CO 2 Photocatalytic reaction Sensitivity analysis Uncertainty analysis

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UDT:U-shaped deformable transformer for subarachnoid haemorrhage image segmentation

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CAAI Transactions on Intelligence Technology 2024年第3期9卷 756-768页

作者： Wei Xie Lianghao Jin Shiqi Hua hao Sun Bo Sun Zhigang Tu jun Liu Hubei Provincial Key Laboratory of Artificial Intelligence and Smart Learning Central China Normal UniversityWuhanChina School of Computer Science Central China Normal UniversityWuhanChina National Language Resources Monitoring and Research Center for Network Media Central China Normal UniversityWuhanChina The First Affiliated Hospital of Dalian Medical University DalianChina State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanChina Information Systems Technology and Design Pillar Singapore University of Technology and DesignSingaporeSingapore

Subarachnoid haemorrhage(SAH),mostly caused by the rupture of intracranial aneu-rysm,is a common disease with a high fatality *** lesions are generally diffusely distributed,showing a variety of scales with irregular *** complex characteristics of lesions make SAH segmentation a challenging *** cope with these difficulties,a u-shaped deformable transformer(UDT)is proposed for SAH ***,first,a multi-scale deformable attention(MSDA)module is exploited to model the diffuseness and scale-variant characteristics of SAH lesions,where the MSDA module can fuse features in different scales and adjust the attention field of each element dynamically to generate discriminative multi-scale ***,the cross deformable attention-based skip connection(CDASC)module is designed to model the irregular edge char-acteristic of SAH lesions,where the CDASC module can utilise the spatial details from encoder features to refine the spatial information of decoder ***,the MSDA and CDASC modules are embedded into the backbone Res-UNet to construct the proposed *** experiments are conducted on the self-built SAH-CT dataset and two public medical datasets(GlaS and MoNuSeg).Experimental results show that the presented UDT achieves the state-of-the-art performance.

关键词： image segmentation medical image processing

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Preparation of vanadium-based electrode materials and their research progress in solid-state flexible supercapacitors

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Rare Metals 2024年第2期43卷 431-454页

作者： Rui-Jie Zhu Jiang Liu Chao Hua hao-Yu Pan Yi-jun Cao Meng Li Zhongyuan Critical Metals Laboratory Zhengzhou UniversityZhengzhou450001China School of Chemical Engineering Zhengzhou UniversityZhengzhou450001China

Solid-state flexible supercapacitors(SCs)have many advantages of high specific capacitance,excellent flexibility,fast charging and discharging,high power density,environmental friendliness,high safety,light weight,ductility,and long cycle *** are the ideal choice for the development of flexible energy storage technology in the future,and provide a good prospect for energy storage *** present,solid-state flexible SCs are widely used for portable electronic equipment and wearable energy storage equipment,the research of them has become the focus of a growing number of *** material is the key part of SCs and always determines the electrochemical performance of *** has been a hotspot and focus of ***-based compounds are considered to be a promising electrode material for SCs because of variable valence,open structure,high theoretical capacity,and low ***,this study first gives an overview of solid-state flexible SCs,then reviews the current research status of vanadium-based electrode materials in solid-state flexible SCs,and proposes some strategies to solve some problems of vanadium-based electrode materials.

关键词： Vanadium-based materials Flexible energy storage Specific capacitance Supercapacitors(SCs)

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FPR1 Antagonist (BOC-MLF) Inhibits Amniotic Epithelial-mesenchymal Transition

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Current Medical Science 2024年第1期44卷 187-194页

作者： Xiao-mei HUANG E LIAO jun-qun LIAO Ya-ling LIU Yong Shao Department of Obstetrics and Gynecology The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400042China Department of Obstetrics Maternal and Child Health Hospital of Hubei ProvinceWuhan 430070China Medical Laboratory Science The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400042China Department of Obstetrics Yubei Maternity and Child Healthcare HospitalChongqing 400042China

Objective:Premature rupture of membranes(PROM)is a common pregnancy disorder that is closely associated with structural weakening of fetal *** have found that formyl peptide receptor 1(FPR1)activates inflammatory pathways and amniotic epithelial-mesenchymal transition(EMT),stimulates collagen degradation,and leads to membrane weakening and membrane *** purpose of this study was to investigate the anti-inflammatory and EMT inhibitory effects of FPR1 antagonist(BOC-MLF)to provide a basis for clinical prevention of ***:The relationship between PROM,FPR1,and EMT was analyzed in human fetal membrane tissue and plasma samples using Western blotting,PCR,Masson staining,and ELISA ***(LPS)was used to establish a fetal membrane inflammation model in pregnant rats,and BOC-MLF was used to treat the LPS rat *** detected interleukin(IL)-6 in blood from the rat hearts to determine whether the inflammatory model was successful and whether the anti-inflammatory treatment was *** used electron microscopy to analyze the structure and collagen expression of rat fetal ***:Western blotting,PCR and Masson staining indicated that the expression of FPR1 was significantly increased,the expression of collagen was decreased,and EMT appeared in *** rat model indicated that LPS caused the collapse of fetal membrane epithelial cells,increased intercellular gaps,and decreased ***-MLF promoted an increase in fetal membrane collagen,inhibited EMT,and reduced the weakening of fetal ***:The expression of FPR1 in the fetal membrane of PROM was significantly increased,and EMT of the amniotic membrane was ***-MLF can treat inflammation and inhibit amniotic EMT.

关键词： formyl peptide receptor 1 BOC-MLF epithelial-mesenchymal transition premature rupture of membranes

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Effectiveness of urban distributed runoff model for discharge and water depth calculation in urban drainage pipe networks

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Journal of Hydrodynamics 2024年第3期36卷 582-591页

作者： Yang Zhou Yi-ling Leng Peng-yu Wang Shang-hong Zhang Yu-long Zhu Yu-jun Yi School of Water Resources and Hydropower Engineering North China Electric Power UniversityBeijing102206China State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing100875China

Effective urban land-use re-planning and the strategic arrangement of drainage pipe networks can significantly enhance urban flood defense *** at reducing the potential risks of urban flooding,this paper presents a straightforward and efficient approach to an urban distributed runoff model(UDRM).The model is developed to quantify the discharge and water depth within urban drainage pipe networks under varying rainfall intensities and land-use *** Nash efficiency coefficient of UDRM exceeds 0.9,which indicates its high computational efficiency and potential benefit in predicting urban *** prediction of drainage conditions under both current and re-planned land-use types is achieved by adopting different flood recurrence *** findings reveal that the re-planned land-use strategies could effectively diminish flood risk upstream of the drainage pipe network across 20-year and 50-year flood recurrence ***,in the case of extreme rainfall events(a 100-year flood recurrence),the re-planned land-use approach fell short of fulfilling the requirements necessary for flood disaster *** these instances,the adoption of larger-diameter drainage pipes becomes an essential requisite to satisfy drainage ***,the proposed UDRM effectively combines land-use information with pipeline data to give practical suggestions for pipeline modification and land-use optimization to combat urban ***,this methodology warrants further promotion in the field of urban re-planning.

关键词： Stormwater runoff water depth urban distributed runoff model urban drainage pipe networks urban land-use re-planning

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Safe Motion Planning and Control Framework for Automated Vehicles with Zonotopic TRMPC

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Engineering 2024年第2期33卷 146-159页

作者： hao Zheng Yinong Li ling Zheng Ehsan Hashemi State Key Laboratory of Mechanical Transmissions College of Mechanical and Vehicle EngineeringChongqing UniversityChongqing 400044China Department of Mechanical Engineering University of AlbertaEdmontonAB T6G 2H5Canada

Model mismatches can cause multi-dimensional uncertainties for the receding horizon control strategies of automated vehicles(AVs).The uncertainties may lead to potentially hazardous behaviors when the AV tracks ideal trajectories that are individually optimized by the AV's planning *** address this issue,this study proposes a safe motion planning and control(SMPAC)framework for *** the control layer,a dynamic model including multi-dimensional uncertainties is established.A zonotopic tube-based robust model predictive control scheme is proposed to constrain the uncertain system in a bounded minimum robust positive invariant set.A flexible tube with varying cross-sections is constructed to reduce the controller *** the planning layer,a concept of safety sets,representing the geometric boundaries of the ego vehicle and obstacles under uncertainties,is *** safety sets provide the basis for the subsequent evaluation and ranking of the generated *** efficient collision avoidance algorithm decides the desired trajectory through the intersection detection of the safety sets between the ego vehicle and obstacles.A numerical simulation and hardware-in-the-loop experiment validate the effectiveness and real-time performance of the *** result of two driving scenarios indicates that the SMPAC can guarantee the safety of automated driving under multi-dimensional uncertainties.

关键词： Automated vehicles Automated driving Motion planning Motion control Tube MPC Zonotope

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