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

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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

Insect-specific RNA virus affects the stylet penetration activity of brown citrus aphid(Aphis citricidus)to facilitate its transmission

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Insect Science 2024年第1期31卷 255-270页

作者： Xin An Qiaoying Gu Jing Wang Tengyu Chang wei zhang Jin-jun Wang Jinzhi Niu Key Laboratory of Entomology and Pest Control Engineering College of Plant ProtectionAcademy of Agricultural ScienceSouthwest UniversityChongqingChina

Sap-sucking insects often transmit plant viruses but also carry insect viruses,which infect insects but not *** impact of such insect viruses on insect host biology and ecology is largely ***,we identified a novel insect-specific virus carried by brown citrus aphid(Aphis citricidus),which we tentatively named Aphis citricidus picornavirus(AcPV).Phylogenetic analysis discovered a monophyletic cluster with AcPV and other unassigned viruses,suggesting that these viruses represent a new family in order *** infection with AcPV triggered aphid antiviral immunity mediated by RNA interference,resulting in asymptomatic ***,we found that AcPV was transmitted horizontally by secretion of the salivary gland into the feeding sites of *** influenced aphid stylet behavior during feeding and increased the time required for intercellular penetration,thus promoting its transmission among aphids with plants as an intermediate *** gene expression results suggested that this mechanism was linked with transcription of salivary protein genes and plant defense hormone ***,our results show that the horizontal transmission of AcPV in brown citrus aphids evolved in a manner similar to that of the circulative transmission of plant viruses by insect vectors,thus providing a new ecological perspective on the activity of insect-specific viruses found in aphids and improving the understanding of insect virus ecology.

关键词： electrical penetration graph feeding behavior insect virus transmission Picornavirales salivary protein

Experimental study and simulation on the creep characteristics of machineharvested seed cotton

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International Journal of Agricultural and Biological Engineering 2024年第1期17卷 241-250页

作者： Ximei wei Hongwen zhang jun Wang Shufeng Li Lei Wang Xintian Du College of Mechanical and Electrical Engineering Shihezi UniversityShihezi 832003XinjiangChina Key Laboratory of Northwest Agricultural Equipment Ministry of AgricultureShihezi 832003XinjiangChina

In view of the unclear understanding of the basic scientific problems such as the rheological mechanism of seed cotton,especially the lack of research on the creep characteristics of seed cotton,the machine-harvested seed cotton in the Xinjiang region was taken as the research object to find out the compression creep *** universal material testing machine was used to carry out a one-factor creep test,taking moisture content,feed quality,compression times,and trash content as test factors and instantaneous elastic modulus,hysteretic elastic modulus,viscosity coefficient,and delay time as test *** ANOVA and correlation were analyzed by SPSS,and the creep process of the seed cotton was simulated by *** show that moisture content significantly affects the instantaneous elastic modulus,hysteretic elastic modulus,and viscosity coefficient(p<0.01).In addition,each value of which decreases with the increase in moisture *** quality significantly affects the hysteretic elastic modulus and viscosity coefficient(p<0.05).Moreover,the hysteretic elastic modulus and viscosity coefficient increase with the increase in feed *** compression times significantly influence the instantaneous elastic modulus,hysteretic elastic modulus,and viscosity coefficient(p<0.01),each value of which increases with the increase of compression ***,the trash content significantly influenced the hysteretic elastic modulus and viscosity coefficient(p<0.05).The absolute error between the simulated and experimental values ek is within−0.011-0.030 mm,and the relative errorφk is less than 7%.The experimental results can provide theoretical and data support for the study of rheological characteristics of machine-harvested seed cotton,the design of seed cotton packing devices,and the molding quality of cotton bale(mold).

关键词： creep characteristics machine-harvested seed cotton analysis of ANOVA one-factor tests ADAMS

LT(K63/R72),a New Mutant of Escherichia coli Heat-labile Enterotoxin,Exhibits Characteristics More Similar to LT(K63)than LT(R72)

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Acta Biochimica et Biophysica Sinica 2005年第2期37卷 126-132页

作者： Qiang FENG jun YANG Ping LUO wei-jun zhang Quan-Ming ZOU Department of Clinical Microbiology and Immunology.Third Military Medical University.Chongqing 400038.China Department of Life Sciences and Chemistry,Chongqing Education College.Chongqing 400067,China Department of Clinical Microbiology and Immunology Third Military Medical University Chongqing 400038 China Department of Life Sciences and Chemistry Chongqing Education College Chongqing 400067 China

LT(K63),a non-toxic mutant and LT(R72),a low toxic mutant of *** heat-labile enterotoxinare frequently used mucosal *** many cases,the adjuvanticity of LT(K63)is lower than that of LT(R72),but LT(K63),which induces a mixed Th1/Th2 response,exhibits a higher level of protection than LT(R72)which induces a polarized Th2-type *** utilize the advantages of both adjuvants,a double-mutation LT(K63/R72)was generated and *** characterization results showed that there was nosignificant difference in production rate and immunogenicity between wild type LT and LT *** also showed that the toxicity and the trypsin sensitivity of LT(K63/R72)are between that of LT(K63)and LT(R72).Using HPLC,when samples in an OHpak SB-800 column were eluted by denatural buffer(TEAN containing 10mg/ml SDS),we found the stability of LT(K63/R72)was higher than that of LT(R72)and lower than that of LT(K63).Through further analyzes,we found that LT(K63/R72)exhibits character-istics more closely related to LT(K63)than LT(R72).

关键词： Escherichia coli heat-labile enterotoxin mutants LT(K63) LT(R72) LT(K63/R72)

Exhaust hood performance and its improvement technologies in industrial buildings:A literatu rereview

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Building Simulation 2024年第1期17卷 23-40页

作者： Jing zhang Jian Wang jun Gao weimin zhang Architectural Engineering Institute Jinhua PolytechnicJinhua 321017China Institute of HVAC Engineering Schoolof Mechanical EngineeringTongji UniversityShanghai 200092China Tongji Architectural Design(Group)Co .LtdShanghai 200092China

The pollutant control performance of exhaust hoods plays a crucial role in the indoor air quality and energy consumption of ventilation systems in industrial *** better understand the impact of local ventilation on the industrial indoor environment,this paper presents a literature review of exhaust hood performance and its improvement *** create an index for evaluating the performance of exhaust hoods,the capture velocity,capture efficiency,flow ratio of pollutant emissions and exhaust airflow and energy consumption are first introduced.A number of factors affecting exhaust hood performance are assessed such as hood type,hood opening size,exhaust rate,installation distance,pollution source emission and environmental *** to structural improvement methods,the use of active airflow is a more effective way to improve the exhaust hood *** most commonly used methods for determining the exhaust rate are the controlled speed method and the flow ratio *** use of an exhaust hood with an appropriate exhaust rate and jet parameters(for an active air-assisted hood)can effectively improve the pollutant control performance and reduce the energy consumption that would be wasted on the redundant exhaust *** more information focused on exhaust hood performance,this work suggests more effective strategies for improving indoor air quality and reducing energy consumption in industrial buildings.

关键词： industrial ventilation exhaust hood capture efficiency exhaust rate performance improvement

First Digit Distributions of Gamma-Ray Bursts

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Research in Astronomy and Astrophysics 2024年第5期24卷 70-75页

作者： Hou-Yu Lai jun-Jie wei Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China

The occurrence of the first significant digits from real world sources is usually not equally distributed,but is consistent with a logarithmic distribution instead,known as Benford’s *** this work,we perform a comprehensive investigation on the first digit distributions of the duration,fluence,and energy flux of gamma-ray bursts (GRBs) for the first *** a complete GRB sample detected by the Fermi satellite,we find that the first digits of the duration and fluence adhere to Benford’s ***,the energy flux shows a significant departure from this law,which may be due to the fact that a considerable part of the energy flux measurements is restricted by lack of spectral *** on the conventional duration classification scheme,we also check if the durations and fluences of long and short GRBs (with duration T_(90)>2 s and T_(90)≤2 s,respectively) obey Benford’s *** find that the fluences of both long and short GRBs still agree with the Benford distribution,but their durations do not follow Benford’s *** results hint that the long–short GRB classification scheme does not directly represent the intrinsic physical classification scheme.

关键词： (stars:)gamma-ray burst general-methods statistical-astronomical databases miscellaneous

维普期刊数据库

From Liquid to Solid‑State Lithium Metal Batteries:Fundamental Issues and Recent Developments

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Nano-Micro Letters 2024年第2期16卷 68-125页

作者： Zhao zhang wei‑Qiang Han School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027People’s Republic of China

The widespread adoption of lithium-ion batteries has been driven by the proliferation of portable electronic devices and electric vehicles,which have increasingly stringent energy density *** metal batteries(LMBs),with their ultralow reduction potential and high theoretical capacity,are widely regarded as the most promising technical pathway for achieving high energy density *** this review,we provide a comprehensive overview of fundamental issues related to high reactivity and migrated interfaces in ***,we propose improved strategies involving interface engineering,3D current collector design,electrolyte optimization,separator modification,application of alloyed anodes,and external field regulation to address these *** utilization of solid-state electrolytes can significantly enhance the safety of LMBs and represents the only viable approach for advancing *** review also encompasses the variation in fundamental issues and design strategies for the transition from liquid to solid *** noteworthy is that the introduction of SSEs will exacerbate differences in electrochemical and mechanical properties at the interface,leading to increased interface inhomogeneity—a critical factor contributing to failure in all-solidstate lithium metal *** on recent research works,this perspective highlights the current status of research on developing high-performance LMBs.

关键词： Lithium metal batteries All-solid-state lithium metal battery Li dendrite Solid electrolyte Interface

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State of the art of lightweight aggregates used in lightweight refractories for working lining of high-temperature furnaces

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Journal of Iron and Steel Research International 2024年第6期31卷 1320-1343页

作者： wei zhang Wen-yong Dai Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016LiaoningChina Research and Development Department AGC Plibrico(Dalian)Industries Inc.Dalian 116600LiaoningChina

Lightweight refractories for the working lining of high-temperature furnaces play an important role in the smelting of advanced steels and *** prepare lightweight refractories for the working lining of high-temperature furnaces,the synthesis of lightweight aggregates is the ***,the research on the synthesis of lightweight aggregates with high service temperature,low thermal conductivity,high strength,and good slag resistance has received widespread *** available literature on the synthesis of lightweight aggregates was summarized,including corundum,mullite,mullite-corundum,spinel,corundum-spinel,cordierite,cordierite-mullite,calcium hexaluminate,corundum-calcium hexaluminate,bauxite,magnesia,magnesia-based,and forsterite-based ***,the future development trend of lightweight aggregates was proposed.

关键词： Lightweight aggregate Lightweight refractory Working lining Apparent porosity Closed porosity Thermal conductivity Pore-forming approach

Joint Sample Position Based Noise Filtering and Mean Shift Clustering for Imbalanced Classification Learning

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Tsinghua Science and Technology 2024年第1期29卷 216-231页

作者： Lilong Duan wei Xue jun Huang Xiao Zheng School of Computer Science and Technology Anhui University of TechnologyMaanshan 243032China Institute of Artificial Intelligence Hefei Comprehensive National Science CenterHefei 230088China

The problem of imbalanced data classification learning has received much *** classification algorithms are susceptible to data skew to favor majority samples and ignore minority *** weighted minority oversampling technique(MWMOTE)is an effective approach to solve this problem,however,it may suffer from the shortcomings of inadequate noise filtering and synthesizing the same samples as the original minority *** this end,we propose an improved MWMOTE method named joint sample position based noise filtering and mean shift clustering(SPMSC)to solve these ***,in order to effectively eliminate the effect of noisy samples,SPMsC uses a new noise filtering mechanism to determine whether a minority sample is noisy or not based on its position and distribution relative to the majority *** that MWMOTE may generate duplicate samples,we then employ the mean shift algorithm to cluster minority samples to reduce synthetic replicate ***,data cleaning is performed on the processed data to further eliminate class *** on extensive benchmark datasets demonstrate the effectiveness of SPMsC compared with other sampling methods.

关键词： imbalanced data classification oversampling noise filtering clustering