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Design of PD Observers in Descriptor Linear Systems
Ai-Guo Wu,Guang-Ren Duan 대한전기학회 2007 International Journal of Control, Automation, and Vol.5 No.1
A class of new observers in descriptor linear systems, proportional-derivative (PD) observers, are proposed. A parametric design approach for such observers is proposed based on a complete parametric solution to the generalized Sylvester matrix equation. The approach provides complete parameterizations for all the observer gains, gives the parametric expression for the corresponding left eigenvector matrix of the observer system matrix, realizes elimination of impulsive behaviors, and guarantees the regularity of the observer system.
Robust H-infinity Estimation for Linear Time-Delay Systems: An Improved LMI Approach
Ai-Guo Wu,Jin Dong,Guang-Ren Duan 제어·로봇·시스템학회 2009 International Journal of Control, Automation, and Vol.7 No.4
The problem of robust H∞ estimation for the polytopic uncertain linear system with state delay is considered. Firstly, by introducing two auxiliary matrices a new LMI representation of H∞ performance is presented for the linear systems with a single time-varying state delay. The proposed criterion exhibits a kind of separation between the system matrices and the positive definite Lyapunov matrices. So the vertex-dependent Lyapunov functions can be adopted, and thus a less conservative re-sult is expected to be obtained.
( Ai Hua Deng ),( Guo Qiang Zhang ),( Na Na Shi ),( Jie Wu ),( Fu Ping Lu ),( Ting Yi Wen ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.2
A novel protease gene from Bacillus gibsonii, aprBG, was cloned, expressed in B. subtilis, and characterized. High-level expression of aprBG was achieved in the recombinant strain when a junction was present between the promoter and the target gene. The purified recombinant enzyme exhibited similar N-terminal sequences and catalytic properties to the native enzyme, including high affinity and hydrolytic efficiency toward various substrates and a superior performance when exposed to various metal ions, surfactants, oxidants, and commercial detergents. AprBG was remarkably stable in 50% organic solvents and retained 100% activity and stability in 0-4 M NaCl, which is better than the characteristics of previously reported proteases. AprBG was most closely related to the high-alkaline proteases of the subtilisin family with a 57-68% identity. The secretion and maturation mechanism of AprBG was dependent on the enzyme activity, as analyzed by site-directed mutagenesis. Thus, when taken together, the results revealed that the halo-solvent-tolerant protease AprBG displays significant activity and stability under various extreme conditions, indicating its potential for use in many biotechnology applications.
Improved L2-L∞ Filtering for Stochastic Time-delay Systems
Ying Zhang,Ai-Guo Wu,Guang-Ren Duan 제어·로봇·시스템학회 2010 International Journal of Control, Automation, and Vol.8 No.4
The L2-L∞ filtering problem for continuous-time polytopic uncertain stochastic time-delay systems is investigated. The main purpose is to design a full-order filter guaranteeing a prescribed L2-L∞ attenuation level for the filtering error system. A simple alternative proof is given for an enhanced LMI (linear matrix inequality) representation of L2-L∞ performance. Based on the criterion which keeps Lyapunov matrices out of the products of system dynamic matrices, a sufficient condition for the existence of a robust estimator is formulated in terms of LMIs. The corresponding filter design is cast into a convex optimization problem. A numerical example is employed to demonstrate the feasibility and advantage of the proposed design.
Xueying Chai,Zhilu Ai,Jun Liu,Ting Guo,Jingyan Wu,Jie Bai,Qinlu Lin 한국식품과학회 2020 Food Science and Biotechnology Vol.29 No.7
The effects of the secondary metabolite biosynthesison the metabolism and morphology of the Monascuspurpureus were investigated in this study. Hypha andseptum length became longer after deletion of genes pigRand pksCT in M. purpureus LQ-6 by Agrobacteriumtumefaciens-mediated transformation technology, highlybranched hyphae, much smaller and freely dispersedmycelial pellets were observed in M. purpureus. Comparedwith that in the wild-type, the level of intracellular NADHand NADPH was almost constant in M. purpureus DpigRat 4 days, but the NADH and NADPH levels decreased by1.58-fold and 3.71-fold in M. purpureus DpksCT. Thepresent study can not only provide a kind of strategy toimprove the Monascus pigments production, but also providetheoretical support for the further study of relationshipbetween the secondary metabolites, metabolism and morphologicalchange.
Ming-Zhe Hou,Ai-Guo Wu,Guang-Ren Duan 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.2
This paper presents a novel stochastic finite-time stability theorem and gives its application in the finitetimeL2 L¥ filter design for nonlinear stochastic systems. Different form the frequently-used stochastic finitetimestability result, the proposed one does not require that all the states have the same fractional order exponent. Based on this result, a sufficient condition is given for nonlinear stochastic systems to possess the finite-time L2 L¥ performance with a prescribed gain. Further, an existence condition of the finite-time L2 L¥ filter with aprescribed disturbance attenuation level is given for nonlinear stochastic systems with external disturbance inputs. The effectiveness of the obtained results is illustrated by an example.
Almost Disturbance Decoupling for a Class of Inherently Nonlinear Systems
Yan-Ming Fu,Guang-Ren Duan,Ai-Guo Wu 제어·로봇·시스템학회 2009 International Journal of Control, Automation, and Vol.7 No.2
The problem of almost disturbance decoupling (ADD) for a class of inherently nonlinear systems is considered. The controlled systems are beyond triangular form and possess uncontrollable linearization. The performance of ADD is characterized in terms of L2-L2p gain. By using the tool of adding a power integrator, under a set of growth conditions a smooth sate feedback controller is explicitly constructed to attenuate the influence of the disturbance on the output with an arbitrary degree.
Wang Chen-Song,Suo Ni,Huang Hao,Wu Ai-min,Cao Guo-Zhong,Zhang Gui-Feng 한국탄소학회 2019 Carbon Letters Vol.29 No.5
Boron-doped amorphous carbon (BDAC) thin films with a regular oxygen reduction reaction (ORR) catalytic activity were synthesized in a hot filament chemical vapor deposition device using a mixture of CH4 and H2 as a gas source and B2O3 as a boron source and then oxidized in air at 380–470 °C for 15–75 min. Scanning electron microscope, transmission electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, and electrochemical tests were used to characterize the physical and electrochemical properties of the BDAC catalysts. It was concluded that the BDAC catalyst oxidized at 450 °C for 45 min showed the best ORR catalytic activity in alkaline medium. The oxygen reduction potential and the transfer electron number n, respectively, are − 0.286 V versus Ag/AgCl and 3.24 from the rotating disk electrode experiments. The treated carbon film has better methanol resistance and stability than the commercial Pt/C catalyst.
Yuzhu Bai,Hui-Jie Sun,Ai-Guo Wu 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.9
In this paper, the problems of finite-time stability analysis and finite-time stabilization are investigated for Markovian jump linear systems with incomplete transition descriptions. Two sufficient conditions are proposed to guarantee that the system states do not exceed a certain threshold in mean-square sense during a specified time interval for the continuous-time Markovian jump linear systems with partly unknown transition rates and the discretetime Markovian jump linear systems with partly unknown transition probabilities, respectively. On the basis of the above results, two state feedback controllers are developed to solve the finite-time stochastic stabilization problems of the considered systems in continuous-time domain and discrete-time domain, respectively. For the sake of computational convenience, all the conditions are cast in the format of linear matrix inequalities (LMIs). The main feature of the proposed methods is that the total number of LMIs is much less than that in some existing results. Thus, the solution of the finite-time controllers is more concise both in theory and in engineering. In the end, the validity of the developed theoretical results are demonstrated by two illustrative examples.
Chen‑Song Wang,Ni Suo,Hao Huang,Ai‑min Wu,Guo‑Zhong Cao,Gui‑Feng Zhang 한국탄소학회 2019 Carbon Letters Vol.29 No.5
Boron-doped amorphous carbon (BDAC) thin films with a regular oxygen reduction reaction (ORR) catalytic activity were synthesized in a hot filament chemical vapor deposition device using a mixture of CH4 and H2 as a gas source and B2O3 as a boron source and then oxidized in air at 380–470 °C for 15–75 min. Scanning electron microscope, transmission electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, and electrochemical tests were used to characterize the physical and electrochemical properties of the BDAC catalysts. It was concluded that the BDAC catalyst oxidized at 450 °C for 45 min showed the best ORR catalytic activity in alkaline medium. The oxygen reduction potential and the transfer electron number n, respectively, are − 0.286 V versus Ag/AgCl and 3.24 from the rotating disk electrode experiments. The treated carbon film has better methanol resistance and stability than the commercial Pt/C catalyst.