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Huanshui Zhang,Xiao Lu,Weihai Zhang,Wei Wang 대한전기학회 2007 International Journal of Control, Automation, and Vol.5 No.4
The paper deals with the Kalman stochastic filtering problem for linear continuous-time systems with both instantaneous and time-delayed measurements. Different from the standard linear system, the system state is corrupted by multiplicative white noise, and the instantaneous measurement and the delayed measurement are also corrupted by multiplicative white noise. A new approach to the problem is presented by using projection formulation and re-organized innovation analysis. More importantly, the proposed approach in the paper can be applied to solve many complicated problems such as stochastic H∞ estimation, H∞ control stochastic system with preview and so on.
Regulation Control for Discrete-time Stochastic Nonlinear Active Suspension
Likang Feng,Weihai Zhang,Xiaoyu Zhao,Jianwei Xia,Yajuan Liu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.3
The regulation problem of discrete-time stochastic nonlinear active suspension is considered in this paper. Firstly, a stability theorem of practically stable in the mean square sense for discrete-time stochastic systems is given. Secondly, the nonlinear active suspension subject to random disturbances modeled by the stochastic difference equation is obtained by the Euler-Maruyama approximation. Thirdly, a state feedback controller is worked out by a discrete backstepping approach such that the states of the discrete-time stochastic nonlinear active suspension can be regulated to a neighbourhood of zero. Finally, the efficiency can be verified by the simulation results.
Jiling Ding,Weihai Zhang,Junsheng Zhao 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.4
This paper studies the problem of output regulation for a class of high-order nonlinear systems with dynamic uncertainties and unknown powers. Based on the characters of input-to-state stable Lyapunov function and the technique of changing supply rate, a partial-state feedback controller is designed under event-triggered mechanism framework. In the proposed control law, an adaptive dynamic gain is constructed to deal with system uncertainties and eliminate the bad effect of the event-triggered sampling error, and a term of higher power is introduced to compensate the unknown system powers. It is verified that the output tracking error converges into any prescribed small set of the origin and all the closed-loop signals are globally bounded by the proposed partialstate feedback controller, while the Zeno phenomenon is avoided. The effectiveness of the proposed scheme is verified by some simulation results.
Yan, Zhiguo,Zhang, Weihai,Park, Ju H.,Liu, Xiaoping IET 2017 IET control theory & applications Vol.11 No.16
<P>This study is concerned about the quantitative exponential stability (QES) and stabilisation of discrete-time Markov jump systems with multiplicative noises. First, the defects of exponential stability in practical applications are analysed. Based on this analysis, a concept of the QES is given, and two stability criteria are derived. By utilising an auxiliary definition of general finite-time stability (GFTS), the relations among QES, GFTS and finite-time stability are established. Moreover, the quantitative exponential stabilisation is studied, and state feedback controller and the observer-based controller are designed. Subsequently, the relation between the states' upper bound and states' decay rate of considered systems is quantitatively shown by a searching method. Finally, an example is used to illustrate the effectiveness of the authors' obtained results.</P>
Huiying Sun,Liuyang Jiang,Weihai Zhang 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.5
In this paper, we consider the feedback control on nonzero-sum linear quadratic (LQ) differential games in finite horizon for discrete-time stochastic systems with Markovian jump parameters and multiplicative noise. Four-coupled generalized difference Riccati equations (GDREs) are obtained, which are essential to find the optimal Nash equilibrium strategies and the optimal cost values of the LQ differential games. Furthermore, an iterative algorithm is given to solve the four-coupled GDREs. Finally, a suboptimal solution of the LQ differential games is proposed based on a convex optimization approach and a simplification of the suboptimal solution is given. Simulation examples are presented to illustrate the effectiveness of the iterative algorithm and the suboptimal solution.
Stability and Stabilization of Stochastic Systems with Multiplicative Noise
Huiying Sun,Meng Li,Weihai Zhang 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.2
In this paper, stability and stabilization of linear stochastic time-invariant systems are studied based on spectrum technique. Firstly, the relationship among mean square exponential stability, asymptotical mean square stability, second-order moment exponential stability and the spectral location of the systems is revealed with the help of a spectrum operator LA,C. Then, we focus on almost sure exponential stability and stochastic stabilization. A criterion on almost sure exponential stability based on spectrum technique is obtained. Sufficient conditions for mean square exponentially stability and asymptotic mean square stability are given via linear matrix inequality approach and some numerical examples to illustrate the effectiveness of our results are presented.
Critical Stability and Stabilization of Discrete-Time Stochastic Systems and Its Applications
Huiying Sun,Meng Li,Weihai Zhang 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.6
In this paper, critical stability and critical stabilization for discrete stochastic systems with both state and control dependent noise are discussed via the spectrum technique. The Popov-Belevitch-Hautus (PBH) criterion for exact observability in a discrete version is presented. As applications, some interesting results on a class of generalized Lyapunov equations (GLE), unremovable spectra and dis-crete generalized algebraic Riccati equation (GARE) are obtained. Finally, the problem of assigning the spectra of discrete stochastic systems in a specified disk is considered and some numerical examples are given to demonstrate our results.
Wu, Xia,Chi, Xiaoyan,Wang, Yanhua,Zhang, Kailu,Kai, Le,He, Qiuning,Tang, Jinxiu,Wang, Kewen,Sun, Longshuo,Hao, Xiuying,Xie, Weihai,Ge, Yihe The Korean Society of Plant Pathology 2019 Plant Pathology Journal Vol.35 No.4
In our previous study, pyrrolnitrin produced in Pseudomonas chlororaphis G05 plays more critical role in suppression of mycelial growth of some fungal pathogens that cause plant diseases in agriculture. Although some regulators for pyrrolnitrin biosynthesis were identified, the pyrrolnitrin regulation pathway was not fully constructed. During our screening novel regulator candidates, we obtained a white conjugant G05W02 while transposon mutagenesis was carried out between a fusion mutant $G05{\Delta}phz{\Delta}prn::lacZ$ and E. coli S17-1 (pUT/mini-Tn5Kan). By cloning and sequencing of the transposon-flanking DNA fragment, we found that a vfr gene in the conjugant G05W02 was disrupted with mini-Tn5Kan. In one other previous study on P. fluorescens, however, it was reported that the deletion of the vfr caused increased production of pyrrolnitrin and other antifungal metabolites. To confirm its regulatory function, we constructed the vfr-knockout mutant $G05{\Delta}vfr$ and $G05{\Delta}phz{\Delta}prn::lacZ{\Delta}vfr$. By quantifying ${\beta}-galactosidase$ activities, we found that deletion of the vfr decreased the prn operon expression dramatically. Meanwhile, by quantifying pyrrolnitrin production in the mutant $G05{\Delta}vfr$, we found that deficiency of the Vfr caused decreased pyrrolnitrin production. However, production of phenazine-1-carboxylic acid was same to that in the wild-type strain G05. Taken together, Vfr is required for pyrrolnitrin but not for phenazine-1-carboxylic acid biosynthesis in P. chlororaphis G05.
Xia Wu,Xiaoyan Chi,Yanhua Wang,Kailu Zhang,Le Kai,Qiuning He,Jinxiu Tang,Kewen Wang,Longshuo Sun,Xiuying Hao,Weihai Xie,Yihe Ge 한국식물병리학회 2019 Plant Pathology Journal Vol.35 No.4
In our previous study, pyrrolnitrin produced in Pseudomonas chlororaphis G05 plays more critical role in suppression of mycelial growth of some fungal pathogens that cause plant diseases in agriculture. Although some regulators for pyrrolnitrin biosynthesis were identified, the pyrrolnitrin regulation pathway was not fully constructed. During our screening novel regulator candidates, we obtained a white conjugant G05W02 while transposon mutagenesis was carried out between a fusion mutant G05ΔphzΔprn::lacZ and E. coli S17- 1 (pUT/mini-Tn5Kan). By cloning and sequencing of the transposon-flanking DNA fragment, we found that a vfr gene in the conjugant G05W02 was disrupted with mini-Tn5Kan. In one other previous study on P. fluorescens, however, it was reported that the deletion of the vfr caused increased production of pyrrolnitrin and other antifungal metabolites. To confirm its regulatory function, we constructed the vfr-knockout mutant G05Δvfr and G05ΔphzΔprn::lacZΔvfr. By quantifying β-galactosidase activities, we found that deletion of the vfr decreased the prn operon expression dramatically. Meanwhile, by quantifying pyrrolnitrin production in the mutant G05Δvfr, we found that deficiency of the Vfr caused decreased pyrrolnitrin production. However, production of phenazine-1-carboxylic acid was same to that in the wild-type strain G05. Taken together, Vfr is required for pyrrolnitrin but not for phenazine-1-carboxylic acid biosynthesis in P. chlororaphis G05.
Bin Lu,Jingcheng Xu,Ming Zhang,Weihai Pang,Li Xie 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.11
Phosphorus is the crucial factor causing eutrophication in the aquatic ecology. The high phosphorus loading in water bodies may result from the direct disposal of untreated wastewater. In this study, a fluidized bed reactor (FBR) was specially developed to remove and recover phosphorus effectively and efficiently via struvite crystallization. Different physiochemical and hydraulic conditions, including hydraulic retention time (HRT), pH, and molar ratios of Mg : P, N: P and Ca :Mg, were explored to optimize the performance of this improved FBR. For the continuous operating trials, promising removal and recovery efficiencies were achieved at the phosphorus concentration of 25.0mg/L: >90% of phosphorus could be removed under the optimum condition (pH=9, HRT=12 h, Mg : P=1.25 and N : P= 7.5). Increasing the recycle flow rate and prolonging the contact time could also enhance the FBR efficiency. The crystal products obtained in FBR were analyzed in terms of composition and structure. Results indicated that almost pure struvite (>99%) was achieved at low calcium concentrations, which could be considered as a high quality fertilizer.