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Distributed user pairing and effective computation offloading in aerial edge networks

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Chinese Journal of Aeronautics 2024年第4期37卷 378-390页

作者： Wei liang Shuhui WEN Lixin LI jingjing CUI School of Electronics and Information Northwestern Polytechnical UniversityXi’an CN710072China The State Key Laboratory of Integrated Services Networks Xidian UniversityXi’an CN710126China School of Electronics and Computer Science University of SouthamptonSouthampton SO167NSUK

Future Sixth-Generation (6G) mobile communication networks extremely require the global connectivity and the ground Base Stations (BSs) are difficult to develop in some specific areas,such as mountainous areas.Therefore,the aerial networks are the key framework for the future communications,in which the aerial vehicle could act as the access point.Additionally,Mobile Edge Computing (MEC) is also essential to enhance the data processing capabilities of aerial networks.In this paper,we study a comprehensive communication-computation resource management problem for jointly optimizing user pairing,power and time allocation in the MEC aided Cognitive Radio (CR) aerial networks,namely CR-MEC aerial networks.Explicitly,this multilevel optimization problem could be decomposed into the user pairing and power allocation as well as time allocation sub-problems.In the conceived CR-MEC aerial networks,we propose a User Pairing and Computation Offloading Management Algorithm (UPCOMA) based on three-sided matching theory,aiming to minimize the system’s energy consumption.At the first step of UPCOMA,multiple Primary Users (PUs) and Cognitive Users (CUs) on the ground negotiate to each other with the suitable power allocation coefficients and construct the stable user pairs.Moreover,the stable user pairs would match to a high altitude platform who act as the base station,which is for appropriately allocating Transmission Time Slots (TSs) at the second step of UPCOMA.Additionally,a hybrid offloading mode is proposed in our conceived networks in order to support ground users to offload their tasks adaptively according to their individual deadlines.Furthermore,the simulation results reveal that the relative performance of UPCOMA is close to that of the Brute-Force Search Algorithm (BFSA) with low complexity.Meanwhile,the hybrid offloading mode with less energy consumption supports much more ground user pairs to offload tasks compared to the binary mode.

关键词： Aerial edge computing Binary offloading Cognitive radio Hybrid offloading Resource management

A stable implicit nodal integration-based particle finite element method(N-PFEM)for modelling saturated soil dynamics

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2172-2183页

作者： liang Wang Xue Zhang jingjing Meng Qinghua Lei Department of Earth Sciences ETH ZürichZürich8092Switzerland Department of Civil Engineering and Industrial Design University of LiverpoolLiverpoolL693BXUK Department of Civil Environmental and Natural Resources EngineeringLuleåUniversity of TechnologyLuleå97187Sweden Department of Earth Sciences Uppsala UniversityUppsala75105Sweden

In this study,we present a novel nodal integration-based particle finite element method(N-PFEM)designed for the dynamic analysis of saturated soils.Our approach incorporates the nodal integration technique into a generalised Hellinger-Reissner(HR)variational principle,creating an implicit PFEM formulation.To mitigate the volumetric locking issue in low-order elements,we employ a node-based strain smoothing technique.By discretising field variables at the centre of smoothing cells,we achieve nodal integration over cells,eliminating the need for sophisticated mapping operations after re-meshing in the PFEM.We express the discretised governing equations as a min-max optimisation problem,which is further reformulated as a standard second-order cone programming(SOCP)problem.Stresses,pore water pressure,and displacements are simultaneously determined using the advanced primal-dual interior point method.Consequently,our numerical model offers improved accuracy for stresses and pore water pressure compared to the displacement-based PFEM formulation.Numerical experiments demonstrate that the N-PFEM efficiently captures both transient and long-term hydro-mechanical behaviour of saturated soils with high accuracy,obviating the need for stabilisation or regularisation techniques commonly employed in other nodal integration-based PFEM approaches.This work holds significant implications for the development of robust and accurate numerical tools for studying saturated soil dynamics.

关键词： Particle finite element method Nodal integration Dynamic saturated media Second-order cone programming(SOCP)

High-Pressure Behavior of Ferromagnesite(Mg_(0.81)Fe_(0.19))CO_(3)by Synchrotron X-Ray Diffraction and Raman Spectroscopy up to 53 GPa

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Journal of Earth Science 2024年第2期35卷 525-535页

作者： Lin liang Guibin Zhang Shengxuan Huang jingjing Niu Dongzhou Zhang Jingui Xu Wen liang Shan Qin Key Laboratory of Orogenic Belts and Crustal Evolution MOEand School of Earth and Space SciencesPeking UniversityBeijing100871China CAS Center of Excellence in Tibetan Plateau Earth Sciences and Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing100101China Hawai’i Institute of Geophysics and Planetology School of Ocean and Earth Science and TechnologyUniversity of Hawai’i at ManoaHawai’i96822USA Key Laboratory of High Temperature and High Pressure Study of the Earth’s Interior Institute of GeochemistryChinese Academy of SciencesGuiyang550081China

Ferromagnesite(Mg,Fe)CO_(3)with 20 mol%iron is a potential host mineral for carbon transport and storage in the Earth mantle.The high-pressure behavior of synthetic ferromagnesite(Mg_(0.81)Fe_(0.19))CO_(3)up to 53 GPa was investigated by synchrotron X-ray diffraction(XRD)and Raman spectroscopy.The iron bearing carbonate underwent spin transition at around 44–46 GPa accompanied by a volume collapse of 1.8%,which also demonstrated a variation in the dνi/dP slope of the Raman modes.The pressure-volume data was fitted by a third-order Birch-Murnaghan equation of state(BM-EoS)for the high spin phase.The best-fit K_(0)=108(1)GPa and K_(0)'=4.2(1).Combining the dνi/dP and the K_(0),the mode Grüneisen parameters of each vibrational mode(T,L,ν4 andν1)were calculated.The effects of iron concentration on the Mg_(1−x)Fe_(x)CO_(3)system related to high-pressure compressibility and vibrational properties are discussed.These results expand the knowledge of the physical properties of carbonates and provide insights to the potential deep carbon host.

关键词： ferromagnesite synchrotron XRD Raman spectroscopy high pressure geochemistry mineral

Failure transition of shear-to-dilation band of rock salt under triaxial stresses

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 56-64页

作者： Jianfeng Liu Xiaosong Qiu Jianxiong Yang Chao liang jingjing Dai Yu Bian State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China CNPC Key Laboratory of Oil and Gas Underground Storage Engineering Langfang065007China College of Water Resource and Hydropower Sichuan UniversityChengdu610065China

Great potential of underground gas/energy storage in salt caverns seems to be a promising solution to support renewable energy.In the underground storage method,the operating cycle unfortunately may reach up to daily or even hourly,which generates complicated pressures on the salt cavern.Furthermore,the mechanical behavior of rock salt may change and present distinct failure characteristics under different stress states,which affects the performance of salt cavern during the time period of full service.To reproduce a similar loading condition on the cavern surrounding rock mass,the cyclic triaxial loading/unloading tests are performed on the rock salt to explore the mechanical transition behavior and failure characteristics under different confinement.Experimental results show that the rock salt samples pre-sent a diffused shear failure band with significant bulges at certain locations in low confining pressure conditions(e.g.5 MPa,10 MPa and 15 MPa),which is closely related to crystal misorientation and grain boundary sliding.Under the elevated confinement(e.g.20 MPa,30 MPa and 40 MPa),the dilation band dominates the failure mechanism,where the large-size halite crystals are crushed to be smaller size and new pores are developing.The failure transition mechanism revealed in the paper provides additional insight into the mechanical performance of salt caverns influenced by complicated stress states.

关键词： Rock salt Cyclic mechanical loading Shear band Dilation band Underground gas storage(UGS)

Spatiotemporal mapping of(ultra‐)mafic magmatic mine areas:Implications of economic and political realities in China

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Deep Underground Science and Engineering 2024年第1期3卷 91-102页

作者： Heling Li liang Tang Tim T.Werner Zhengmeng Hou Fan Meng jingjing Li College of Earth Sciences Chengdu University of TechnologyChengduChina Institute of Subsurface Energy Systems Clausthal University of TechnologyClausthal ZellerfeldGermany School of Geography Earth and Atmospheric SciencesFaculty of ScienceThe University of MelbourneMelbourneVictoriaAustralia

The spatiotemporal extension/expansion of mine areas is affected by multiple factors.So far,very little has been done to examine the interaction between mine areas and political or economic realities.The(ultra‐)mafic magmatic mines in China played a specific role in supporting national development and providing an ideal research subject for monitoring their interrelationship.In this study,remote sensing and mining‐related GIS data were used to identify and analyze 1233(ultra‐)mafic magmatic mine area polygons in China,which covered approximately 322.96 km2 of land and included a V–Ti–Fe mine,a copper–nickel mine,a chromite mine,an asbestos mine,and a diamond mine.It was found that(1)the areal expansion of mines is significantly related to the mine types,perimeter,topography,and population density.(2)The mine area variation also reflects market and policy realities.The temporal expansion of the mine area from 2010 to 2020 followed an S‐shaped pattern(with the turning point occurring in 2014),closely related to iron overcapacity and tightened mining policies.(3)The complexity(D)of the mine area may reflect mine design and excavation practices.To be specific,lower D indicates early‐stage or artisanal/small‐scale mining,whereas higher D represents large‐scale mining.This study demonstrates that the detailed mapping of mine land can serve as an indicator to implement miningrelated market and policy changes.The(ultra‐)mafic mines area data set can be accessed at https://***/record/7636616#.Y-p0uXaZOa0.

关键词： complexity mine area mining and socioeconomic interaction spatiotemporal distribution (ultra‐)mafic magmatic mine

Recent advances in the stereolithographic three-dimensional printing of ceramic cores: Challenges and prospects

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Journal of Materials Science & Technology 2022年第22期117卷 79-98页

作者： Jinguo Li Xiaolong An jingjing liang Yizhou Zhou Xiaofeng Sun 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 Space Manufacturing Technology(Chinese Academy of Sciences Key Laboratory) Beijing 100094China

The increasing demand for geometrically complex structures—specifically, higher-inlet-temperature turbine blades for the fifth-generation or other high-generation machines of advanced fighter aircrafts—hasmade the development of more complex double-walled three-layer hollow-cavity structures a necessity.However, this requires the preparation of complex ceramic cores and advanced, integrated technologies.Stereolithographic three-dimensional printing (SLA-3DP) technology, with digital control upon materialmorphology, composition, and structure, is a high integration and versatile technique that is superior tothe traditional manufacturing techniques for ceramic cores, including gel casting, injection molding, andhot pressing. The latent capacity of this technique is contingent on the progress of processing routesthat significantly reduce the distortion and defect formation in response to the elimination of the reactedorganic monomer phase during photo-curing. Despite the tremendous progress in the field, multiple challenges remain, such as the preparation of high-solid-content and low-viscosity suspensions, SLA-3DP oflarge double-walled ceramic cores with complex structures, and process optimization and sinter strengthening for the fabrication of ceramic cores. These challenges have prevented the broader applications andreduced the impact of the SLA-3DP technology. This review discusses cutting-edge research on the crucialfactors governing this production method. Specifically, we outline the existing challenges within the fieldand provide our perspective on the upcoming research work and progress.

关键词： Stereolithographic three-dimensional printing Ceramic cores,Cutting-edge research

Beyond microbial carbon use efficiency

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National Science Review 2024年第4期11卷 33-35页

作者： Ke-Qing Xiao Chao liang Zimeng Wang jingjing Peng Yao Zhao Ming Zhang Mingyu Zhao Shuiqing Chen Yong-Guan Zhu Caroline L.Peacock State Key Lab of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of Sciences University of Chinese Academy of Sciences Institute of Applied Ecology Chinese Academy of Sciences Department of Environmental Science and Engineering Fudan University College of Resources and Environmental Sciences China Agricultural University State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental Sciences State Key Laboratory of Agricultural Microbiology College of Resources and Environment Huazhong Agricultural University Key Laboratory of Cenozoic Geology and Environment Institute of Geology and Geophysics Chinese Academy of Sciences School of Earth and Environment University of Leeds

Microbial carbon use efficiency (CUE)is defined as the proportion of microbial biomass growth C versus substrate C uptake, and thus provides a useful measure of microbially driven accumulation and loss of soil organic carbon (SOC)[1]. In a recent study published in Nature [2],the authors used a data-driven machinelearning approach to conclude that CUE promotes global SOC storage based on a positive correlation between CUE and SOC content and that, based on sensitivity analysis, CUE is at least four times as important as six other evaluated factors,namely plant C inputs, C input allocation, non-microbial C transfer, substrate decomposability, environmental modifications and vertical transport.

关键词： SOIL-CARBON ORGANIC-MATTER

Stereolithography 3D printing of ceramic cores for hollow aeroengine turbine blades

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Journal of Materials Science & Technology 2022年第32期127卷 177-182页

作者： Xiaolong An Yahang Mu jingjing liang Jinguo Li Yizhou Zhou Xiaofeng Sun School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Semiconductor Manufacturing International Corporation Shanghai201203China

Hollow superalloy or single-crystal superalloy turbine blades are the most important component of advanced aeroengines for fifth-and higher-generation fighter aircrafts [1,2,3]. The thrust-toweight ratio is largely influenced by the turbine inlet temperature,which places strict requirements on the performance of the turbine blades at high operating temperatures [4]. To reduce the operating temperature of the blades, complex internal cooling structures are required. However, the fabrication of complex cooling channels inside the blades is an unquestionably challenging task [5].

关键词： superalloy ceramic Stereo

Ceramic composites toughened by vat photopolymerization 3D printing technology

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Journal of Materials Science & Technology 2023年第15期146卷 42-48页

作者： Qiaolei Li Zhenxue Pan jingjing liang Zongbo Zhang Jinguo Li Yizhou Zhou Xiaofeng Sun School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Research/Education Centre for Excellence in Molecular Sciences Institute of ChemistryChinese Academy of SciencesBeijing 100190China Space Manufacturing Technology(CAS Key Lab) Beijing 100094China

High strength and high toughness are mutually exclusive in structural materials.In ceramic materials,increasing toughness usually depends on the introduction of a ductile phase that reduces the strength and high-temperature stability of the material.In this work,vat photopolymerization 3D printing technology was used to achieve toughening of ceramic composite material.The friction sliding of the 3D-printed ceramic macrolayer structure results in effective energy dissipation and redistribution of strain in the whole structure,and macroscale toughening of the ceramic material is realized.In addition,the bridging and elongation of the crack in situ amorphous ceramic whiskers were significant microscopic toughening results,coupled with the toughening of the crack tip of nano-ZrO_(2).Multiscale collaborative toughening methods based on 3D-printed ceramics should find wide applications for materials in service at extreme high temperatures.

关键词： Ceramic composites 3D printing Flexure strength Fracture toughness Polysilazane