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Stability of the distributed Kalman filter using general random coefficients

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Science China(Information Sciences) 2021年第7期64卷 66-79页

作者： Die GAN siyu xie Zhixin LIU Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of Sciences School of Mathematical Sciences University of Chinese Academy of Sciences The Department of Electrical and Computer Engineering Wayne State University

In this paper, we propose a distributed Kalman filter(DKF) for the dynamical system with general random coefficients. In the proposed method, each estimator shares local innovation pairs with its neighbors to collectively complete the estimation task. Further, we introduce a collective random observability condition by which the Lp-stability of the covariance matrix and the Lp-exponential stability of the homogeneous part of the estimation error equation can be established. In contrast, the stringent conditions on the coefficient matrices, such as independency and stationarity are not required. Besides, the stability of the DKF, i.e., the boundedness of the filtering errors, can be established. Finally, from the simulation result,we demonstrate the cooperative effect of the sensors.

关键词： distributed Kalman filter collective random observability L p-stable L p-exponentially stable state estimation

Compressed Least Squares Algorithm of Continuous-Time Linear Stochastic Regression Model Using Sampling Data

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Journal of Systems Science & Complexity 2024年第4期37卷 1488-1506页

作者： xie siyu ZHANG Shujun WANG Ziming GAN Die School of Aeronautics and Astronautics University of Electronic Science and Technology of ChinaChengdu 611731China China Academy of Aerospace Science and Innovation Beijing 100176China Zhongguancun Laboratory Beijing 100094China

In this paper,the authors consider a sparse parameter estimation problem in continuoustime linear stochastic regression models using sampling *** on the compressed sensing(CS)method,the authors propose a compressed least squares(LS) algorithm to deal with the challenges of parameter *** each sampling time instant,the proposed compressed LS algorithm first compresses the original high-dimensional regressor using a sensing matrix and obtains a low-dimensional LS estimate for the compressed unknown ***,the original high-dimensional sparse unknown parameter is recovered by a reconstruction *** introducing a compressed excitation assumption and employing stochastic Lyapunov function and martingale estimate methods,the authors establish the performance analysis of the compressed LS algorithm under the condition on the sampling time interval without using independence or stationarity conditions on the system *** last,a simulation example is provided to verify the theoretical results by comparing the standard and the compressed LS algorithms for estimating a high-dimensional sparse unknown parameter.

关键词： Compressed excitation condition compressed sensing continuous-time model least squares linear stochastic regression parameter identification sampling data

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

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Visualized thermoresponsive helix-helix switch of polyphenylacetylene with a wide-range tunable transition temperature

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Science China Chemistry 2023年第3期66卷 887-895页

作者： Sheng Wang siyu xie Hongxu Du Hua Zeng Jie Zhang Xinhua Wan Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Polymers with tunable helicity and naked-eye structural change under external stimuli are valuable for fabricating smart materials. Herein, we report a novel thermoresponsive color and fluorescent polyphenylacetylene switch with a tunable critical temperature. It relies on the temperature and solvent sensitivity of intramolecular n→π* interactions between the vicinal carbonyl groups of ester substituents located at 3,5-positions, which are indispensable for forming the cis-cisoid helical conformation of polyene backbones. In a properly chosen solvent, a compressed cis-cisoid helix is stabilized by n→π* interactions at low temperatures and yields a colorless solution. Increasing temperature causes the conformational transition toward an extended cis-transoid helix due to the disruption of n→π* interactions and produces a yellow solution. Reducing the hydrogen bond donating ability or polarity of solvents increases the switching temperature. By introducing a fluorogenic pendant, this conformational transition can also be read out by fluorescence quenching. This work may open a new window for developing intelligent materials through precisely tuning conformational transitions.

关键词： polyphenylacetylene thermoresponsive conformation transition fluorescent switch n→π*interaction

Distributed optimization with Markovian switching targets and stochastic observation noises with applications to DC microgrids

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Science China(Information Sciences) 2022年第12期65卷 232-247页

作者： siyu xie Leyi WANG Masoud H.NAZARI George YIN Gun LI School of Aeronautics and Astronautics University of Electronic Science and Technology of China Department of Electrical and Computer Engineering Wayne State University Department of Mathematics University of Connecticut

A distributed optimization problem with Markovian switching targets and stochastic observation noises is considered in this paper. In order to solve target following and renewable following for microgrid(MG) optimal power balancing, and to attenuate observation noises simultaneously, distributed optimization algorithms are developed. The interaction between observation noises and Markovian switching targets may introduce a fundamental tradeoff in reducing the optimization errors and choosing the step size. Furthermore, under infrequent Markovian switching assumptions, the mean-square optimization error bounds, the switching ordinary differential equation(ODE) limit, and the asymptotic distributions of the optimization errors are established rigorously and comprehensively. A simulation example on a DC MG is presented to show the main results of the paper.

关键词： constraint optimization noisy observation output variation Markovian switching target distributed algorithm DC microgrid

Effect of stereoregularity on excitation-dependent fluorescence and room-temperature phosphorescence of poly(2-vinylpyridine)

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Aggregate 2023年第2期4卷 267-274页

作者： Hongxu Du Wenjing Zhao Yijie Xia siyu xie Yi Tao Yi Qin Gao Jie Zhang Xinhua Wan Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijingChina Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijingChina

Preparation of non-conjugated luminescent polymers(NCLPs)with excellent cluster luminescence(CL)performance is of great significance for scientific and industrious applications,and yet improving the performance of NCLPs through proper structural design is still a huge ***,we report a non-conjugated ionized polymeric system consisting of(−)-camphorsulfonic acid((−)-CSA)and poly(2-vinylpyridine)(P2VP).These acid-base complexes exhibit typical excitationdependent fluorescence and room-temperature phosphorescence(RTP)with a lifetime up to 364 *** discover that changing the stereoregularity from atactic to isotactic significantly improves the CL performance of the ***(1)broadens the fluorescence emission spectra to cover the entire visible region,(2)enhances the fluorescence emission intensity at long wavelength beyond 500 nm,(3)enhances the phosphorescence intensity,and(4)extends the phosphorescence *** experimental characterization and molecular dynamics simulation unravel the key role of stereoregularity in determining the formation of different pyridine aggregates that strongly influence the CL ***,the different luminescence shows great potential in excitation divided information display and time-resolved encrypted *** work not only points to a new direction for developing NCLPs with excellent performance,but also broadens the applications of NCLPs materials.

关键词： cluster luminescence excitation-dependent fluorescence poly(2-vinylpyridine) room-temperature phosphorescence stereoregularity

Functional butter for reduction of consumption risk and improvement of nutrition

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Grain & Oil Science and Technology 2023年第4期6卷 172-184页

作者： Shujie Cheng Wei Li Shimin Wu Yuxing Ge Caiyun Wang siyu xie Juan Wu Xiangke Chen Ling-Zhi Cheong Department of Food Science and Technology School of Agriculture and BiologyShanghai Jiao Tong University800 Dongchuan RoadShanghai 200240China National Center of Technology Innovation for Dairy Hohhot 010000China School of Agriculture Food and Ecosystem SciencesThe University of MelbourneParkville 3010VictoriaAustralia

Butter has become renowned among consumers because of its exceptional flavor and ***,conventional butter is deemed“unhealthy”due to its high concentration of saturated fats and cholesterol,which are linked to the development of cardiovascular *** the health benefits of butter has become an essential topic of research in the butter *** review focuses on researches that have made improvements to functionality of butter,including the changes in fatty acid composition,cholesterol reduction,incorporation with bioactive substances,development of new *** reduction of saturated fatty acids and cholesterol in butter can help reduce the risk of disease from eating *** addition,incorporating probiotics or natural plant extracts can achieve nutritional functions such as balancing intestinal flora,enhancing nutrient absorption,and increasing the body’s antioxidant *** substitute products can be based on new vegetable oils,insect fats or microbial fats,which cater to the consumer demands for low-calorie butter while reducing the environmental impact that results from butter *** review summarizes the effects and characteristics of various improvement methods and proposes some possible directions for future development of functional butter.

关键词： Improved butter Butter substitute Food function Nutrition Bioactive ingredient

Different Ablation Models for the Wall-plasma Interaction Process in Pulsed Plasma Thruster

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高电压技术 2013年第9期39卷 2301-2308页

作者： YANG Lei LIU Xiangyang WANG siyu xie Kan WU Zhiwen WANG Ningfei Beijing Institute of Technology School of Aerospace Engineering Beijing 100081 China

Ablation excited by current pulses is a very critical physical process in pulse plasma thrusters(PPT).Its effects on wall-plasma interaction directly determine the PPT *** order to reveal the process of the ablated wall interaction with the discharge plasma in PPT,ablation models formulated by three different boundary conditions at the wall-plasma interface are *** are the two widely used high-speed evaporation models(Model-L and Model-M),and the recently developed Keida-Zaghloul model(Model-K)of the Knudsen layer that takes into account the internal degrees of freedom on the energy flux ***,fundamental mechanisms of the three ablation models are clarified by comparative analysis in order to gain a comprehensive understanding of the wall-plasma ***,the applicability of different ablation models with the numerical solutions of LES-6 PPT is investigated in detail using magnetohydrodynamic(MHD)*** show that Model-L and Model-M are actually special cases of Model-K when a simplified jump conditions limited by high velocity at the vapor/plasma interface is used;A ratio of ablation rate in Model-L to that in Model-M is about 0.8at the same wall surface temperature,while it rises to 1 at different surface temperature determined by Model-L and Model-M in *** though Model-K solution requires significant computational time,it shows more accurate ablation feature for the wall-plasma interaction and possesses better computing precision of impulse bit during post-pulse which is useful for future studies of the late time ablation.

关键词：等离子体推进器蒸发模型电流脉冲壁挂式脉冲等离子体推力器相互作用交互放电等离子体

间充质干细胞疗法在肾移植中的应用:一个未完待续的故事

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器官移植 2024年第3期15卷 398-405页

作者：谢思雨路君中国人民解放军联勤保障部队第九〇〇医院福建省移植生物学重点实验室福州350025

免疫抑制药是预防器官移植术后排斥反应的主要手段,但会降低机体对病原体的反应能力,导致感染等的风险增加。近年来,间充质干细胞(MSC)疗法在实体器官移植领域的应用备受关注。临床前研究表明,MSC疗法能够延长移植肾存活时间,诱导免疫耐... 详细信息

免疫抑制药是预防器官移植术后排斥反应的主要手段,但会降低机体对病原体的反应能力,导致感染等的风险增加。近年来,间充质干细胞(MSC)疗法在实体器官移植领域的应用备受关注。临床前研究表明,MSC疗法能够延长移植肾存活时间,诱导免疫耐受,加速急性肾损伤修复,促进肾功能恢复。临床试验则验证了MSC疗法的安全性、耐受性和有效性。因此,本文对MSC的一般特性、MSC的免疫调节和组织修复作用以及MSC在肾移植临床试验中的应用进行综述,简要讨论待继续研究的问题和对未来的展望,旨在为推动MSC治疗在临床肾移植中的应用提供参考。

关键词：间充质干细胞肾移植免疫调节组织修复外泌体免疫抑制药排斥反应炎症

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