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Multi-UAV Collaborative Edge Computing Algorithm for Joint Task Offloading and Channel Resource Allocation

Journal of Communications and Information Networks 2024年第2期9卷 137-150页

作者： Yuting Wei Sheng wu Zhe Ji zhigang Yu Chunxiao Jiang Linling Kuang School of Information and Communication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China China Academy of Electronics and Information Technology Beijing 100041China Beijing National Research Center for Information Science and Technology Tsinghua Space CenterTsinghua UniversityBeijing 100084China

Unmanned aerial vehicle (UAV)-based edge computing is an emerging technology that provides fast task processing for a wider area. To address the issues of limited computation resource of a single UAV and finite communication resource in multi-UAV networks, this paper joints consideration of task offloading and wireless channel allocation on a collaborative multi-UAV computing network, where a high altitude platform station (HAPS)is adopted as the relay device for communication between UAV clusters consisting of UAV cluster heads (ch-UAVs) and mission UAVs (m-UAVs). We propose an algorithm, jointing task offloading and wireless channel allocation to maximize the average service success rate (ASSR)of a period time. In particular,the simulated annealing(SA)algorithm with random perturbations is used for optimal channel allocation,aiming to reduce interference and minimize transmission delay.A multi-agent deep deterministic policy gradient (MADDPG) is proposed to get the best task offloading strategy. Simulation results demonstrate the effectiveness of the SA algorithm in channel allocation. Meanwhile,when jointly considering computation and channel resources,the proposed scheme effectively enhances the ASSR in comparison to other benchmark algorithms.

关键词： UAV-based edge computing multi-UAV collaboration joint task offloading and wireless channel allocation simulated annealing(SA)algorithm multi-agent deep deterministic policy gradient(MADDPG)

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骨性Ⅲ类错[牙合]术前正畸治疗后颞下颌关节关节盘及髁突位置和形态观察

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蚌埠医学院学报 2024年第3期49卷 326-330页

作者：李婕张凯吴志刚田绣云高廷益田瑞雪蚌埠医科大学第一附属医院口腔科安徽蚌埠233004

目的:探讨术前正畸对Ⅲ类错牙合病人关节盘及髁突位置和形态的影响。方法:选取40例骨性Ⅲ类错牙合畸形病人为研究对象。在颞下颌关节磁共振图像上测定关节上间隙、前间隙、后间隙,判定髁突位置;通过测量髁突头长度、宽度和高度,判定髁... 详细信息

目的:探讨术前正畸对Ⅲ类错牙合病人关节盘及髁突位置和形态的影响。方法:选取40例骨性Ⅲ类错牙合畸形病人为研究对象。在颞下颌关节磁共振图像上测定关节上间隙、前间隙、后间隙,判定髁突位置;通过测量髁突头长度、宽度和高度,判定髁突形态;通过直接观察判定关节盘位置和形态。比较骨性Ⅲ类畸形病人术前正畸前后关节盘及髁突位置和形态变化。结果:骨性Ⅲ类错牙合病人正畸前左侧和右侧关节上间隙均小于正畸后,正畸前左侧和右侧关节前间隙、后间隙、内间隙均大于正畸后,但差异均无统计学意义(P>0.05);正畸后左侧和右侧关节间隙指数较正畸前均有增加,趋向前位,仍处于中心范围,差异均无统计学意义(P>0.05)。病人正畸后左侧和右侧髁突头宽度、髁突头高度、髁突头长度较正畸前均有减小趋势,但差异均无统计学意义(P>0.05)。病人颞下颌关节关节盘位置为后型的病例最多,正畸后该类型的病例有所减少,正畸前后四种关节盘位置的病人比例差异均无统计学意义(P>0.05)。正畸前病人关节盘形态为双凹形的病人最多,其次为双平面型,正畸前后两种关节盘形态病人的比例差异无统计学意义(P>0.05)。结论:目前制定的术前正畸方案,对于Ⅲ类错牙合病人的关节盘及髁突位置和形态的影响不大。

关键词：骨性Ⅲ类错牙合术前正畸颞下颌关节

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Laser-assisted grinding of RB-SiC composites:Laser ablation behavior and mechanism

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Chinese Journal of Aeronautics 2024年第1期37卷 362-376页

作者： zhigang DONG Wenchao SUN Xintong CAI Feng YANG Yan BAO Renke KANG Dongjiang wu Guangyi MA Fangyong NIU Key Laboratory for Precision and Non-traditional Machining Technology of the Ministry of Education School of Mechanical EngineeringDalian University of TechnologyDalian 116024China

Laser ablation is an important process during Laser-Assisted Grinding(LAG)of hard and brittle *** realize controllable material removal during laser ablation of RB-SiC composites,ablation experiments under different Laser Energy Density(LAED)and LAG experiments are *** rules and mechanism of physical phase,ablation morphology and crack characteristics caused by laser irradiation are *** forces of LAG and Conventional Grinding(CG)are *** results show that ablation surface changes from slight oxidation to obvious material removal with LAED increasing,and ablation depth increases *** ablation products change from submicron SiO_(2)particles to nanoscale particles and *** LAED promotes SiC decomposition and sublimation,which leads to the increase of C *** SiC phase forms corrugated shape in recast layer and columnar shape in Heat Affected Zone(HAZ)at 56 J/mm^(2).The cold and heat cycle leads to formation of fishbone *** ablation specimen under 30 J/mm^(2),the grinding force can be reduced by a maximum of 39%and brittle damage region is *** material removal and microcrack generated will significantly reduce the hardness and improve machinability,which can promote grinding efficiency.

关键词： RB-SiC Laser Ceramic Composites Grinding

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Microstructure Evolution,Tribological and Corrosion Properties of Amorphous Alloy Strengthening Stainless Steel Fabricated by Selective Laser Melting in NaCl Solution

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Acta Metallurgica Sinica(English Letters) 2024年第5期37卷 825-839页

作者： Pengwei Jiang Gang Wang Yaosha wu zhigang Zheng Zhaoguo Qiu Tongchun Kuang Jibo Huang Dechang Zeng School of Materials Science and Engineering South China University of TechnologyGuangzhou 510640China Zhongshan R&D Center for Materials Surface and Thin Films Technology of the South China University of Technology Gent Materials Surface Technology(Guangdong)Co.Ltd.Zhongshan 528437China Zhongshan Torch Polytechnic Zhongshan 528436China Yangjiang Branch Guangdong Laboratory Materials Science and Technology Yangjiang Advanced Alloys LaboratoryYangjiang 529599China

As a type of austenitic stainless steel,316L stainless steel has excellent plasticity,corrosion resistance,and biocompatibility,making it widely used in industries,especially in the marine ***,its lower yield strength and wear resistance are the obvious disadvantages that restrict its application in more *** this work,an Fe-based amorphous alloy(Fe^(am))was selected as reinforcement to enhance the 316L stainless steel prepared by selective laser melting(SLM),and microstructure evolution,mechanical properties,tribological and corrosion performance of the SLMed samples were investigated in *** relative density values of both 316L stainless steel and Fe^(am)-reinforced samples are above 99%,which suggests that Fe^(am)-reinforced samples also have outstanding *** the as-etched micrograph,all of the SLMed samples exhibit cellular ***^(am)-reinforced samples have thicker sub-grain boundaries,and retained amorphous phase can be observed in the samples reinforced with 10 wt%and 15 wt%Fe^(am).As the addition of Fe^(am) increases,the microhardness and compression strength of the Fe^(am)-reinforced samples gradually improve and reach 449.2 HV and 2181.9 MPa,*** wear morphologies show that the 316L stainless steel and Fe^(am)-reinforced samples both experience abrasive wear and corrosion wear in a 3.5 wt%NaCl ***,as the amount of Fe^(am) added increases,the coefficient of friction and wear rate of SLMed samples gradually *** to the unreinforced sample,Fe^(am)-reinforced samples have lower corrosion current density and higher pitting potential according to the potentiodynamic polarization curves and also exhibit superior corrosion resistance in the salt spray *** work suggests that the addition of Fe-based amorphous alloy can improve the mechanical properties and wear resistance of 316L stainless steel,as well as its ability to withstand salt spray corrosion.

关键词： Selective laser melting 316L stainless steel Amorphous alloy Tribology Corrosion

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Characteristics of microscopic pore heterogeneity and development model of wufeng‒Longmaxi Shales in the Pengshui area of south-east Chongqing

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Frontiers of Earth Science 2024年第1期18卷 188-203页

作者： Lu SUN zhigang WEN Guisong HE Peixian ZHANG Chenjun wu Liwen ZHANG Yingyang XI Bo LI College of Resources and Environment Yangtze UniversityWuhan 430100China Research Institute of Exploration and Development Sinopec East China CompanyNanjing 210011China

Normal-pressure shale gas reservoirs are widely distributed in south-eastern Chongqing and show good potential for resource *** paper reports the organic matter(OM),physical,and pore characteristics,mineral composition,and gas content of representative shale samples from the Upper Ordovician wufeng Formation and Member 1 of the Lower Silurian Longmaxi Formation(Long 1 Member).Microscopic pores within different shale layers of the Long 1 Member were classified,quantitatively evaluated,and their development mechanisms were systematically *** found that OM characteristics,mineral composition,and pore type were the main factors affecting the enrichment and preservation of shale *** characteristics of the Long 1 Member are mainly controlled by changes in the sedimentary *** are evident differences in total organic carbon content and mineral composition vertically,leading to a variable distribution of pores across different *** matter abundance controls the degree of OM pore development,while clay minerals abundance control the development of clay mineral-related *** organic carbon content generally controls the porosity of the Long 1 Member,but clay minerals also play a role in OM-poor *** connectivity and permeability are influenced by the development of pores associated with brittle *** propose a microscopic pore development model for the different *** geochemical data and this pore development model,layers 1‒4 are considered to be excellent shale gas preservation and enrichment *** preservation conditions in layers 5‒7 result in high levels of shale gas *** 8‒9 possess a better sealing condition compared with layers 5‒7 and are conducive to the enrichment and preservation of shale gas,and can thus be used as future potential target *** research provides a theoretical basis for exploring and evaluating shale gas potential in the studied region or other co

关键词： shale gas pore characteristics Longmaxi Formation reservoir model

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Intermolecular hydrogen-bonding as a robust tool toward significantly improving the photothermal conversion efficiency of a NIR-II squaraine dye

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Chinese Chemical Letters 2024年第4期35卷 310-315页

作者： Songtao Cai Liuying wu Yuan Li Soham Samanta Jinying Wang Bing Liu Feihu wu Kaitao Lai Yingchao Liu Junle Qu zhigang Yang Center for Biomedical Photonics&Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China

The photothermal therapy(PTT) has come across as a promising noninvasive therapeutic strategy for tumor treatment. However, low photothermal conversion efficiency(PCE) and hydrophobicity may impede the therapeutic efficacy of organic photothermal agents and an efficient PTT-agent must overcome these two major challenges. In this work, we developed a new strategy to promote higher PCE wherein the intermolecular hydrogen-bonding interaction between the single dye molecule and water facilitated the transformation of the absorbed energy into the heat. A hydrophilic squaraine dye(SCy1) with the second near-infrared region(NIR-II) absorption and extremely low emission were designed to exhibit much higher PCE than that of the analogues of pentamethine-dyes(PCy1, PCy2). The presence of the ‘–O-' at middle of squaric cycle enabled the intermolecular H-bonding formation between the SCy1 and water to promote the energy dissipation channel. Moreover, the introduction of long-chain phenylsulfonate groups helped in to improve the water solubility apart from serving as an additional means of further enhancing PCE through fluorescence quenching. Therefore, SCy1 with a squaraine backbone and long-chain sulfonate moieties revealed outstanding photothermal stability and anti-aggregation activity apart from showing exceptionally high PCE(74%) in water. SCy1 demonstrated excellent therapeutic efficacy when applied in the PTT treatment of tumor-bearing mice under a laser irradiation of 915 nm.

关键词： Squaraine-based cyanine Hydrogen bonds High PCE Anti-aggregation Photothermal therapy

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Gust response modeling and alleviation scheme design for an elastic aircraft

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Science China(Technological Sciences) 2010年第11期53卷 3110-3118页

作者： wu zhigang CHEN Lei YANG Chao TANG ChangHong School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China The First Institute Aviation Industry Corporation of ChinaXi’an 710089China

Time-domain approaches are presented for analysis of the dynamic response of aeroservoelastic systems to atmospheric gust excitations. The continuous and discrete gust inputs are defined in the time domain. The time-domain approach to continuous gust response uses a state-space formulation that requires the frequency-dependent aerodynamic coefficients to be approximated with the rational function of a Laplace variable. A hybrid method which combines the Fourier transform and time-domain approaches is used to calculate discrete gust response. The purpose of this approach is to obtain a time-domain state-space model without using rational function approximation of the gust columns. Three control schemes are designed for gust alleviation on an elastic aircraft, and three control surfaces are used: aileron, elevator and spoiler. The signals from the rate of pitch angle gyroscope or angle of attack sensor are sent to the elevator while the signals from accelerometers at the wing tip and center of gravity of the aircraft are sent to the aileron and spoiler, respectively. All the control laws are based on classical control theory. The results show that acceleration at the center of gravity of the aircraft and bending-moment at the wing-root section are mainly excited by rigid modes of the aircraft and the accelerations at the wing-tip are mainly excited by elastic modes of the aircraft. All the three control schemes can be used to alleviate the wing-root moments and the accelerations. The gust response can be alleviated using control scheme 3, in which the spoiler is used as a control surface, but the effects are not as good as those of control schemes 1 and 2.

关键词： aeroelastic aeroservoelastic gust response gust alleviation control scheme design

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Design optimization and testing of a morphing leading-edge with a variable-thickness compliant skin and a closed-chain mechanism

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Chinese Journal of Aeronautics 2024年第7期37卷 285-300页

作者： zhigang WANG Xiasheng SUN Yu YANG Wenjie GE Daochun LI Jinwu XIANG Panpan BAO Qi wu Andrea DA RONCH School of Aeronautical Science and Engineering Beihang UniversityBeijing 100191China National Key Laboratory of Strength and Structural Integrity Aircraft Strength Research Institute of ChinaXi’an 710065China School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China Faculty of Engineering and Physical Sciences University of SouthamptonSouthampton SO171JBUK

Climate warming and the increased demand in air travels motivate the aviation industry to urgently produce technological *** of the most promising innovations is based on the smoothly continuous morphing leading-edge *** study proposes a two-step process for the design of a morphing leading-edge,including the optimization of the outer variable-thickness composite compliant skin and the optimization of the inner kinematic *** the compliant skin design,an optimization of the variable thickness composite skin is proposed based on a laminate continuity model,with laminate continuity constraint and other manufacturing *** laminate continuity model utilizes a guiding sequence and a ply-drop sequence to describe the overall stacking sequence of plies in different thickness regions of the complaint *** the inner kinematic mechanism design,a coupled four-bar linkage system is proposed and optimized to produce specific trajectories at the actuation points on the stringer hats of the compliant skin,which ensures that the compliant skin can be deflected into the aerodynamically optimal ***,a morphing leading-edge is manufactured and *** results are compared with numerical predictions,confirming the feasibility of the morphing leading-edge concept and the overall proposed design approach.

关键词： Optimization Design Morphing wing Compliant skin Kinematics Leading-edge Control surfaces

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Remote heteroepitaxy of transition metal dichalcogenides through monolayer hexagonal boron nitride

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Nano Research 2024年第4期17卷 3224-3231页

作者： Jidong Huang Jingren Chen Junhua Meng Siyu Zhang Ji Jiang Jingzhen Li Libin Zeng zhigang Yin Jinliang wu Xingwang Zhang Key Lab of Semiconductor Materials Science Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Faculty of Science Beijing University of TechnologyBeijing 100124China

As a very promising epitaxy technology,the remote epitaxy has attracted extensive attention in recent years,in which graphene is the most used interlayer *** an isomorphic of graphene,two-dimensional(2D)hexagonal boron nitride(h-BN),is another promising interlayer for the remote ***,there is a current debate on the feasibility of using h-BN as interlayer in the remote ***,we demonstrate that the potential field of sapphire can completely penetrate monolayer h-BN,and hence the remote epitaxy of ZrS_(2) layers can be realized on sapphire substrates through monolayer *** field of sapphire can only partially penetrate the bilayer h-BN and result in the mixing of remote epitaxy and van der Waals(vdWs)*** to the weak interfacial scattering and high crystalline quality of ZrS_(2) epilayer,the ZrS_(2) photodetector with monolayer h-BN shows the best performance,with an on/off ratio of more than 2×10^(5) and a responsivity up to 379 mA·W^(-1).This work provides an efficient approach to prepare single-crystal transition metal dichalcogenides and their heterojunctions with h-BN,which have great potential in developing large-area 2D electronic devices.

关键词： remote epitaxy hexagonal boron nitride transition metal dichalcogenides chemical vapor deposition photodetectors

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Distributed vibration control of a large solar power satellite

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Astrodynamics 2019年第2期3卷 189-203页

作者： Enmei Wang Shunan wu Yufei Liu zhigang wu Xiangdong Liu School of Aeronautics and Astronautics Dalian University of TechnologyDalian 116024China Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100094China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian 116024China School of Automation Bejing Institute of TechnologyBejing 100081China

To deal with the vibration problem of the solar power satellite(SPS),the distributed vibration control approach is investigated in this *** the Multi-Rotary joints SPS as the research objective,the control unit(CU)and the location relationship matrix are rstly de ned for distributed controller design according to the con guration of *** dynamic model of each CU is therefore established based on the nite element *** dynamic model of the whole SPS structure is then developed using the CU models,and is updated along with on-orbit *** distributed cooperative controller,using proportional and di erential feedback and the interaction feedback among adjacent CUs,is proposed to suppress *** close-loop distributed cooperative control system is then achieved by integrating all distributed controllers,and the asymptotic stability is proofed by the Lyapunov's stability *** verify the feasibility of the proposed control system,three numerical cases are nally *** results demonstrate that the distributed cooperative controllers can e ectively suppress vibration during on-orbit assembly and operation after assembly,and the closed-loop system has good fault tolerance.

关键词： solar power satellite vibration control distributed control on-orbit assembly

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