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Spatial distribution of supra-permafrost groundwater in the Qinghai-Tibet Engineering Corridor using inversion models

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Advances in Climate Change Research 2024年第1期15卷 31-41页

作者： yu GAO Ming-Tang CHAI Wei MA yu-Tao GAO State Key Laboratory of Frozen Soils Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 73000China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China School of Civil and Hydraulic Engineering Ningxia UniversityYinchuan 750021China

Supra-permafrost groundwater(SPG)is a key factor that causes damage to highways and railways in the Qinghai-Tibet Engineering Corridor(QTEC).It is difficult to monitor SPG in the field due to their complex formation mechanisms and movement *** single-site field monitoring studies limit the spatial and temporal precision of SPG spatial *** determine the moisture content of shallow soils and the SPG distribution along the QTEC,this work employed the temperature vegetation dryness index and remote sensing models for groundwater table distribution *** accuracies of the models were validated using mea-surements obtained from different sites in the *** the permafrost zones of the QTEC,72%,22%and 6%of the SPG were located at depths of 0.5-1,1 m,***,79.4%of the area along the Qinghai-Tibet Highway(QTH)(Xidatan-Tanggula)section contained *** these sections with SPG,37.9%have an SPG table at depths of 0.5-0.8 *** study preliminarily explored the SPG distribution in the QTEC with a 30 m *** findings can help improve the spatial scale of SPG research,provide a basis for the analysis of the hydrothermal mechanisms,and serve as a guide in the assessment of operational risks and road structure designs.

关键词： Dryness index Landsat Soil moisture Groundwater level Qinghai-Tibet Engineering Corridor

Exploiting blockchain for dependable services in zero-trust vehicular networks

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Frontiers of Computer Science 2024年第2期18卷 157-166页

作者： Min HAO Beihai TAN Siming WANG Rong yu Ryan Wen LIU Lisu yu School of Automation Guangdong University of TechnologyGuangzhou 510006China School of Integrated Circuits Guangdong University of TechnologyGuangzhou 510006China School of Navigation Wuhan University of TechnologyWuhan 430063China School of Information Engineering Nanchang UniversityNanchang 330031China

The sixth-generation(6G)wireless communication system is envisioned be cable of providing highly dependable services by integrating with native reliable and trustworthy ***-trust vehicular networks is one of the typical scenarios for 6G dependable *** the technical framework of vehicle-and-roadside collaboration,more and more on-board devices and roadside infrastructures will communicate for information *** reliability and security of the vehicle-and-roadside collaboration will directly affect the transportation *** a zero-trust vehicular environment,to prevent malicious vehicles from uploading false or invalid information,we propose a malicious vehicle identity disclosure approach based on the Shamir secret sharing ***,a two-layer consortium blockchain architecture and smart contracts are designed to protect the identity and privacy of benign vehicles as well as the security of their private *** that,in order to improve the efficiency of vehicle identity disclosure,we present an inspection policy based on zero-sum game theory and a roadside unit incentive mechanism jointly using contract theory and subjective logic *** verify the performance of the entire zero-trust solution through extensive simulation *** the premise of protecting the vehicle privacy,our solution is demonstrated to significantly improve the reliability and security of 6G vehicular networks.

关键词： sixth-generation(6G) zero-trust block-chain vehicular networks privacy preservation

An Adaptive Consensus Based Distributed Particle Filter for Cooperative Object Tracking

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An Adaptive Consensus Based Distributed Particle Filter for ...

Investigation on the vortical structures by the Liutex method in turbulent channels at Re_(τ)=180 with scalloped and triangular riblet control

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作者： wentao yu Xiaoyong Zhang Aibin Chen Kuo-chi Lin College of Computer and Information Engineering Central South University of Forestry and Technology School of Information Science and Engineering Central South University Department of Mechanical and Aerospace Engineering University of Central Florida

ISBN: (纸本)9781538629185

Object tracking is a fundamental skill of mobile *** a multi-robot system the object tracking accuracy of each robot is usually different because of the dynamic environment and the different sensing *** focus of cooperative object tracking is how to fuse different robots’ observation to obtain more robust and accurate estimation of the *** paper investigates this problem using an adaptive consensus based distributed particle filter *** this algorithm,each robot runs a particle filter to achieve local object *** a consensus algorithm which can establish an agreement between all robots is utilized to generalize a global posterior about the object *** fully consider the difference between each robot’s object tracking accuracy,Renyi entropy is used to adaptively adjust the weight of the consensus *** concept of Renyi entropy is utilized to measure the distance between a robot’s local posterior and the global posterior and then a weight will be assigned to the robot according to the Renyi *** weight will be used continuously in the next consensus *** the proposed algorithm in this paper the accuracy and the robust of the cooperative can be *** the effectiveness of the proposed algorithm is verified by simulation results.

关键词： consensus distributed particle filter Renyi entropy cooperative object tracking

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Journal of Hydrodynamics 2024年第1期36卷 35-52页

作者： Zhang-dan yu Shang Jiang Hai-dong yu Bi-yu Pang Xin Dong Yi-qian Wang School of Mathematical Sciences Soochow UniversitySuzhou215006China Beijing Institute of Astronautical System Engineering Beijing100076China

Riblets are a series of small protrusions formed along the flow direction,which have been extensively studied as a passive turbulent drag reduction *** and numerical simulations have shown that well-designed riblets can significantly reduce drag in turbulent flows,making them highly promising and valuable for various *** this study,we focus on a scalloped riblet,which is designed by smoothly connecting two third-order polynomials,and thus the sharpness of the tip and the curvature of the valley can be well *** conduct direct numerical simulations of turbulent channel with smooth plate,scalloped riblet-mounted and triangular riblet-mounted *** in wall units of W^(+)=20 and height-width ratio ofγ=0.5 are selected for both riblet *** with the smooth plate case,the scalloped riblet case achieves an 8.68%drag reduction,while the triangular riblet case achieves a 4.79%drag *** obtained drag reduction rate of the triangular riblet is consistent with previous experiments and simulations,and the results indicate that the scalloped riblet is more effective in reducing drag and deserves further *** compare turbulent statistics of the scalloped riblet case with those of the triangular riblet *** mean velocity profiles of riblets are similar,but both the Reynolds shear stress and second-order statistics of velocity fluctuations and Liutex are significantly reduced in the scalloped riblets controlled turbulent channel,indicating that the scalloped riblet can more effectively suppress the spanwise and wall-normal turbulent intensity near the *** also compare the pre-multiplied spectra of streamwise velocity and streamwise Liutex component for the three cases to investigate the energy distribution and characteristics of Liutex *** Liutex vortex identification method is also utilized to analyze the instantaneous flow field,which provides insights into the flow field and could be bene

关键词： Liutex vector riblet drag reduction tip sharpness turbulent channel scalloped

Transcriptomic and cellular decoding of scaffolds-induced suture mesenchyme regeneration

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International Journal of Oral Science 2024年第2期16卷 306-321页

作者： Jiayi Wu Feifei Li Peng yu Changhao yu Chuyi Han Yitian Wang Fanyuan yu Ling Ye State Key Laboratory of Oral Diseases&National Center for Stomatology&National Clinical Research Center for Oral Diseases&West China Hospital of Stomatology Sichuan UniversityChengduChina State Key Laboratory of Oral Diseases&National Center for Stomatology&National Clinical Research Center for Oral Diseases&Department of Cariology and Endodontics West China Hospital of StomatologySichuan UniversityChengduChina State Key Laboratory of Oral Diseases&National Center for Stomatology&National Clinical Research Center for Oral Diseases&Department of Pediatric Dentistry West China Hospital of StomatologySichuan UniversityChengduChina

Precise orchestration of cell fate determination underlies the success of scaffold-based skeletal *** extensive studies on mineralized parenchymal tissue rebuilding,regenerating and maintaining undifferentiated mesenchyme within calvarial bone remain very challenging with limited advances *** knowledge has evidenced the indispensability of rebuilding suture mesenchymal stem cell niches to avoid severe brain or even systematic *** to date,the absence of promising therapeutic biomaterials/scaffolds *** reason lies in the shortage of fundamental knowledge and methodological evidence to understand the cellular fate regulations of *** address these issues,in this study,we systematically investigated the cellular fate determinations and transcriptomic mechanisms by distinct types of commonly used calvarial *** data elucidated the natural processes without scaffold transplantation and demonstrated how different scaffolds altered in vivo cellular responses.A feasible scaffold,polylactic acid electrospinning membrane(PLA),was next identified to precisely control mesenchymal ingrowth and self-renewal to rebuild non-osteogenic suture-like tissue at the defect center,meanwhile supporting proper osteointegration with defect bony ***,transcriptome analysis and cellular mechanisms underlying the well-orchestrated cell fate determination of PLA were *** study for the first time cellularly decoded the fate regulations of scaffolds in suture-bony composite defect healing,offering clinicians potential choices for regenerating such complicated injuries.

关键词： injuries healing suture

Efficient degradation of aqueous dichloromethane by an enhanced microbial electrolysis cell:Degradation kinetics,microbial community and metabolic mechanisms

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Journal of Environmental Sciences 2024年第5期139卷 150-159页

作者： Meng Wu Di Zhao Bing Gu ZiruWang Jun Hu Zhiliang yu Jianming yu College of Environment College of Biotechnology and BioengineeringCollaborative Innovation Center of Yangtze River Delta Region Green PharmaceuticalsZhejiang University of TechnologyHangzhou 310014China Shentuo Environment(Hangzhou)Co.Ltd. Hangzhou 311121China Zhejiang Tianyi Environmental Co.Ltd. Hangzhou 310000China

Dichloromethane(DCM)has been listed as a toxic and harmful water pollutant,and its re moval needs *** electrolysis cells(MECs)are viewed as a promising alterna tive for pollutant removal,which can be strengthened from two aspects:microbial inocula tion and *** this study,the MEC for DCM degradation was inoculated with the ac tive sludge enhanced by Methylobacterium rhodesianum H13(strain H13)and then acclimated in the form of a microbial fuel cell(MFC).Both the introduction of strain H13 and the initi ation in MFC form significantly promoted DCM *** degradation kinetics were fitted by the Haldane model,with V_(max),K_(h),K_(i)and v_(max)values of 103.2 mg/L/hr,97.8 mg/L268.3 mg/L and 44.7 mg/L/hr/cm^(2),*** cyclic voltammogram implies that DCM redox reactions became easier with the setup of MEC,and the electrochemical impedance spectrogram shows that the acclimated and enriched microbes reduced the charge transfe resistance from the electrode to the *** the biofilm,the dominant genera shifted from Geobacter to Hyphomicrobium in acclimation ***,Methylobacterium played an increasingly important *** metabolism mainly occurred through the hydrolytic glutathione S-transferase pathway,given that the gene dcmA was identified rather than the dhlA and P450/*** exogenous electrons facilitated the reduction of GSSG,directly o indirectly accelerating the GSH-catalyzed *** study provides support fo the construction of an efficient and stable MEC for DCM removal in water environment.

关键词： Dichloromethane Microbial electrolysis cells Metabolic pathways Electron transfer Degradation kinetics

An integrative mathematical model of microwave ion thruster for mHz-frequency thrust noise analysis

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Chinese Journal of Aeronautics 2024年第4期37卷 121-136页

作者： Xiang NIU Hui LIU Daren yu Plasma Propulsion Laboratory Harbin Institute of TechnologyHarbin 150001China

Many high-precision space missions need thrusters to produce thrust with low noise to compensate for disturbances and ensure satellite platform stability. Microwave ion thruster is characterized with a wide thrust range and potential for these missions. A cost-effective and accurate mathematical model is crucial for mHz-frequency thrust noise analysis and feedback controller design. The Particle-In-Cell(PIC) and global models are two common simulation tools. The PIC model is characterized with high accuracy but huge computation cost, which is difficult to analyze long-time performance characteristics. Now, the global model is only used for the discharge chamber with low accuracy and cannot reflect ion extraction properties. In this paper, an integrative mathematical model is built for a 1-cm microwave ion thruster and can reflect ion beamlet divergence and impingement on the Accelerator Grid(AG). Simulation results show good agreement with experiments at 0.06 sccm. However, the model demonstrates worse consistency with experiments when the flux increases to 0.1 sccm, which may be because the influence of neutral gas on the Electron Cyclotron Resonance(ECR) is not considered in the model. A long-time(1000 s) simulation is conducted with this model under 35 μN. It takes 3 hrs, and the thrust noise reaches 1 μN/Hz^(0.5) at 1 mHz.

关键词： Electric propulsion Microwave ion thruster Integrative model Sheath property Ion beamlet divergence Thrust noise Plasma

Partial Linear Model Averaging Prediction for Longitudinal Data

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Journal of Systems Science & Complexity 2024年第2期37卷 863-885页

作者： LI Na FEI yu ZHANG Xinyu Faculty of Science Kunming University of Science and TechnologyKunming 650500China School of Statistics and Mathematics Yunnan University of Finance and EconomicsKunming 650221China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

Prediction plays an important role in data *** averaging method generally provides better prediction than using any of its *** though model averaging has been extensively investigated under independent errors,few authors have considered model averaging for semiparametric models with correlated *** this paper,the authors offer an optimal model averaging method to improve the prediction in partially linear model for longitudinal *** model averaging weights are obtained by minimizing criterion,which is an unbiased estimator of the expected in-sample squared error loss plus a *** properties,including asymptotic optimality and consistency of averaging weights,are established under two scenarios:(i)All candidate models are misspecified;(ii)Correct models are available in the candidate *** studies and an empirical example show that the promise of the proposed procedure over other competitive methods.

关键词： Asymptotic optimality longitudinal data model averaging estimator partially linear model prediction

A Comparison of Four Neural Networks Algorithms on Locomotion Intention Recognition of Lower Limb Exoskeleton Based on Multi-source Information

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Journal of Bionic Engineering 2024年第1期21卷 224-235页

作者： Duojin Wang Xiaoping Gu Hongliu yu Institute of Rehabilitation Engineering and Technology University of Shanghai for Science and Technology516 Jungong RoadShanghai 200093China Shanghai Engineering Research Center of Assistive Devices 516 Jungong RoadShanghai 200093China

Lower Limb Exoskeletons(LLEs)are receiving increasing attention for supporting activities of daily *** such active systems,an intelligent controller may be *** this paper,we proposed a locomotion intention recognition system based on time series data sets derived from human motion *** of input data and Deep Learning(DL)algorithms,this framework enables the detection and prediction of users’movement *** makes it possible to predict the detection of locomotion modes,allowing the LLEs to provide smooth and seamless *** pre-processed eight subjects were used as input to classify four scenes:Standing/Walking on Level Ground(S/WOLG),Up the Stairs(US),Down the Stairs(DS),and Walking on Grass(WOG).The result showed that the ResNet performed optimally compared to four algorithms(CNN,CNN-LSTM,ResNet,and ResNet-Att)with an approximate evaluation indicator of 100%.It is expected that the proposed locomotion intention system will significantly improve the safety and the effectiveness of LLE due to its high accuracy and predictive performance.

关键词： Lower limb exoskeletons(LLEs) Locomotion intention ResNet Multi-source