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stability and performance analysis of the compressed Kalman filter algorithm for sparse stochastic systems

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science China(Technological sciences) 2024年第2期67卷 380-394页

作者： lI RongJiang GAN Die xie siYu lüJinHu Key laboratory of systems and Control Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China school of Mathematical sciences University of Chinese Academy of SciencesBeijing 100049China Zhongguancun laboratory Beijing 100049China school of Aeronautics and Astronautics University of Electronic Science and Technology of ChinaChengdu 611731China school of Automation science and Electrical Engineering Beihang UniversityBeijing 100191China

This paper considers the problem of estimating unknown sparse time-varying signals for stochastic dynamic *** deal with the challenges of extensive sparsity,we resort to the compressed sensing method and propose a compressed Kalman filter(KF)*** algorithm first compresses the original high-dimensional sparse regression vector via the sensing matrix and then obtains a KF estimate in the compressed low-dimensional ***,the original high-dimensional sparse signals can be well recovered by a reconstruction *** ensure stability and establish upper bounds on the estimation errors,we introduce a compressed excitation condition without imposing independence or stationarity on the system signal,and therefore suitable for feedback *** further present the performance of the compressed KF ***,we show that the mean square compressed tracking error matrix can be approximately calculated by a linear deterministic difference matrix equation,which can be readily evaluated,analyzed,and ***,a numerical example demonstrates that our algorithm outperforms the standard uncompressed KF algorithm and other compressed algorithms for estimating high-dimensional sparse signals.

关键词： sparse signal compressed sensing Kalman filter algorithm compressed excitation condition stochastic stability tracking performance

Control Policy learning Design for Vehicle Urban Positioning via BeiDou Navigation

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Journal of systems science & Complexity 2024年第1期37卷 114-135页

作者： QIN Yahang ZHANG Chengye CHEN Ci xie shengli lEWIs Frank l school of Automation Guangdong University of TechnologyGuangzhou 510006China Guangdong Key laboratory of IoT Information Technology Guangzhou 510006China. Center for Intelligent Batch Manufacturing Based on IoT Technology Key laboratory of Intelligent Detection and The Internet of Things in Manufacturing Ministry of EducationGuangzhou 510006China Guangdong-HongKong-Macao Joint laboratory for smart Discrete Manufacturing Guangzhou 510006China Key laboratory of Intelligent Information Processing and system Integration of IoT Ministry of EducationGuangzhou 510006China. UTA Research Institute The University of Texas at ArlingtonFort WorthTX 76019USA

This paper presents a learning-based control policy design for point-to-point vehicle positioning in the urban environment via BeiDou *** navigating in urban canyons,the multipath effect is a kind of interference that causes the navigation signal to drift and thus imposes severe impacts on vehicle localization due to the reflection and diffraction of the BeiDou ***,the authors formulated the navigation control system with unknown vehicle dynamics into an optimal control-seeking problem through a linear discrete-time system,and the point-to-point localization control is modeled and handled by leveraging off-policy reinforcement learning for feedback *** proposed learning-based design guarantees optimality with prescribed performance and also stabilizes the closed-loop navigation system,without the full knowledge of the vehicle *** is seen that the proposed method can withstand the impact of the multipath effect while satisfying the prescribed convergence rate.A case study demonstrates that the proposed algorithms effectively drive the vehicle to a desired setpoint under the multipath effect introduced by actual experiments of BeiDou navigation in the urban environment.

关键词： BeiDou navigation multipath effect prescribed convergence rate reinforcement learning urban localization.

Mass extinctions, their causes and consequences: an interview with Douglas *** and shuzhong shen

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National science Review 2024年第1期11卷 66-70页

作者： shucheng xie state Key laboratory of Biogeology and Environmental Geology China University of Geosciences at Wuhan

‘Mass extinctions’ have been a hot topic for several decades. What triggers a mass extinction? How does a mass extinction impact the evolution of life? How does our ecosystem recover after a mass extinction? These questions attracted the interest of both scientists and the public *** spoke to two renowned researchers in the field of mass extinctions: Prof. Douglas H. Erwin from the National Museum of Natural History of the UsA, and Prof. shuzhong shen from Nanjing University, China.

关键词： stratigraphy

Evolution of microstructure and properties of a novel Ni-based superalloy during stress relief annealing

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1876-1889页

作者： lei Jia Heng Cui shufeng Yang shaomin lü Xingfei xie Jinglong Qu Collaborative Innovation Center of steel Technology University of Science and Technology BeijingBeijing 100083China state Key laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Beijing GAONA Materials&Technology Co. Ltd.Beijing 100081China High-Temperature Materials Institute Central Iron and Steel Research InstituteBeijing 100081China

We discussed the decrease in residual stress,precipitation evolution,and mechanical properties of GH4151 alloy in different annealing temperatures,which were studied by the scanning electron microscope(sEM),high-resolution transmission electron microscopy(HRTEM),and electron backscatter diffraction(EBsD).The findings reveal that annealing processing has a significant impact on diminishing residual *** the annealing temperature rose from 950 to 1150℃,the majority of the residual stresses were relieved from 60.1 MPa down to 10.9 ***,the stress relaxation mechanism transitioned from being mainly controlled by dislocation slip to a combination of dislocation slip and grain boundary ***,the annealing treatment promotes the decomposition of the laves,accompanied by the precipitation ofμ-(Mo_(6)Co_(7))starting at 950℃ and reaching a maximum value at 1050℃.The tensile strength and plasticity of the annealing alloy at 1150℃ reached the maximum(1394 MPa,56.1%)which was 131%,200%fold than those of the as-cast alloy(1060 MPa,26.6%),but the oxidation process in the alloy was accelerated at 1150℃.The enhancement in durability and flexibility is primarily due to the dissolution of the brittle phase,along with the shape and dispersal of theγ′phase.

关键词： GH4151 alloy annealing treatment residual stress precipitation evolution strength mechanical properties

Turbulence statistics of Thermo-Buoyancy supercritical Fuel Flow in a Regenerative Cooling Channel

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Journal of Thermal science 2024年第1期33卷 126-137页

作者： sUN Feng xie Gongnan school of Marine science and Technology Northwestern Polytechnical UniversityXi'an 710072China Department of Thermal Engineering Tsinghua UniversityBeijing 100084China

Active regenerative cooling with supercritical hydrocarbon fuel is considered as the most promising thermal protection *** existence of buoyancy force would lead to strongly anisotropic flow and thermal transport *** is closely related to the cooling performance of the *** elucidate the mechanisms of turbulent transport,the large eddy simulation(lEs) was performed to assess turbulence statistics within different turbulence *** results indicated that the buoyancy and inertial force together dominated the change of turbulent ***,the spatial thermal buoyancy effect significantly suppressed the vertical velocity *** is due to the laminar motion caused by the buoyancy force,thereby weakening the thermal *** the statistics of velocity fluctuation,it was found that the buoyancy force and inertial force greatly weaken the vertical and streamwise velocity fluctuation,*** the statistics of thermal transport,the results pointed out that the near-wall heat transport characteristics need to be paid more *** thickness of the temperature mixing boundary layer led to the attenuation of vertical heat flux,which inhibited vertical temperature diffusion and predisposed to extreme conditions of heat transfer *** results can enhance the academic understanding of the heat transfer mechanism of supercritical fluids,and give guidance for further applications of thermal protection.

关键词： active regenerative cooling large eddy simulation(lEs) buoyancy force turbulence statistics

Water-soluble brown carbon in atmospheric aerosols from the resource-dependent cities:Optical properties,chemical compositions and sources

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Journal of Environmental sciences 2024年第4期138卷 74-87页

作者： Haoji Wang Yue su Yangzheng liu Fei xie Xingjun Zhou Ruihong Yu Changwei lü Jiang He school of Ecology and Environment Inner Mongolia UniversityHohhot 010021China Institute of Environmental Geology Inner Mongolia UniversityHohhot 010021China Environmental Monitoring Center of Inner Mongolia Hohhot 010011China

As a vital type of light-absorbing aerosol,brown carbon(BrC)presents inherent associations with atmospheric photochemistry and climate ***,the understanding of the chemical and optical properties of BrC is limited,especially in some resource-dependent cities with long heating periods in northwest *** study showed that the annual average abundances of Water-soluble BrC(Ws-BrC)were 9.33±7.42 and 8.69±6.29μg/m^(3)in Baotou and Wuhai and the concentrations,absorption coefficient(Abs_(365)),and mass absorption efficiency(MAE365)of Ws-BrC presented significant seasonal patterns,with high values in the heating season and low values in the non-heating season;while showing opposite seasonal trends for the Absorption Angstr?m exponent(AAE_(300-400)).Comparatively,the levels of Ws-BrC in developing regions(such as cities in Asia)were higher than those in developed regions(such as cities in Europe and Australia),indicating the significant differences in energy consumption in these *** combining fluorescence excitation-emission matrix(EEM)spectra with the parallel factor(PARAFAC)model,humic-like(C1 and C2)and proteinlike(C3)substances were identified,and accounted for 61.40%±4.66%and 38.6%±3.78%at Baotou,and 60.33%±6.29%and 39.67%±4.17%at Wuhai,*** results of source apportionment suggested that the potential source regions of Ws-BrC varied in heating ***-heating seasons and that the properties of Ws-BrC significantly depended on primary emissions(e.g.,combustion emissions)and secondary formation.

关键词： Water-soluble brown carbon Atmospheric aerosols Optical properties PARAFAC source apportionment

Output feedback stabilization of stochastic high-order planar nonlinear systems with stochastic inverse dynamics and output-constraint

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science China(Information sciences) 2024年第3期67卷 182-196页

作者： Ruiming xie shengyuan XU Nanjing University of science and Technology school of Automation

In this paper, we solve the output feedback control problem of stochastic high-order planar nonlinear systems with output constraint and stochastic integral input-to-state stability(siIss) inverse dynamics. By employing a key coordinate transformation, a stochastic nonlinear system with output constraint and siIss inverse dynamics is converted into an unconstrained system. By skillfully constructing an observer and adopting siIss small-gain conditions, we develop a new output feedback control design and analysis method, and prove that all the closed-system signals are bounded almost surely, the output constraint is not violated almost surely, and the equilibrium point of the closed-loop system is stochastically asymptotically stable.

关键词： stochastic high-order planar nonlinear system outputconstraint stochastic inverse dynamics output feedbackstabilization stochastic integral input-to-state stability(siIss)

Morphology and phylogenetic placement of Mallomonas vietnamica(synurales,Chrysophyceae)from China

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Journal of Oceanology and limnology 2024年第4期42卷 1325-1335页

作者： Junxue HAO Fangru NAN Junping lÜ Qi lIU Xudong lIU shulian xie Jia FENG school of life science Shanxi UniversityTaiyuan 030006China

The newly described chrysophyte,Mallomonas vietnamica,is reported for the first time in China from specimens collected in Guizhou Province,sW *** morphological characteristics were studied using light and scanning electron *** species was described based on morphological characteristics,including cell size,scale size,dome,V-rib,and ***,molecular sequencing of *** was conducted and a phylogenetic tree was constructed based on concatenated ssU,lsU,and rbc l *** phylogenetic tree led us to suggest raising a new section named Uncatusipedae for this *** study provides new molecular data from the genus Mallomonas and enriches our understanding of the species diversity and geographical distribution of the genus Mallomonas in China.

关键词： Chrysophyta Mallomonas vietnamica phylogenetic study taxonomy

Fixed-time stabilization of output-constrained stochastic high-order nonlinear systems

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science China(Information sciences) 2024年第4期67卷 5-20页

作者： Ruiming xie shengyuan XU Nanjing University of science and Technology school of Automation

In this study, the fixed-time stabilization problem of stochastic high-order nonlinear systems with output constraint and high-order and low-order nonlinearities is addressed. A new coordinate transformation is employed to directly convert output-constrained stochastic systems into an equivalent unconstrained *** fully extracting the characteristics of system nonlinearities and using the stochastic fixed-time stability theorem, a new design and analysis method is constructed to guarantee that the trivial solution of the closed-loop system is stochastically fixed-time stable while fulfilling the output constraint.

关键词： stochastic high-order nonlinear system outputconstraint high-order and low-order nonlinearity fixed-timestabilization finite-time stabilization