Non-fragile decentralized H∞ controller design for uncertain linear systems

Considering the design problem of non-fragile decentralized H∞ controller with gain variations, the dynamic feedback controller by measurement feedback for uncertain linear systems is constructed and studied. The parameter uncertainties are considered to be unknown but norm bounded. The design procedures are investigated in terms of positive definite solutions to modify algebraic Riccati inequalities. Using information exchange among local controllers, the designed non-fragile decentralized H∞ controllers guarantee that the uncertain closed-loop linear systems are stable and with H∞ -norm bound on disturbance attenuation. A sufficient condition that there are such non-fragile H∞ controllers is obtained by algebraic Riccati inequalities. The approaches to solve modified algebraic Riccati inequalities are carried out preliminarily. Finally, a numerical example to show the validity of the proposed approach is given.     

Ras /MAPK / ERK 通过协同 NF- KB 促进肝癌细胞中 cyclinD1 的表达

摘要: 目的 探讨 Ras 癌基因在体内诱导肝肿瘤发生过程中促进 cyclin D1 表达的分子机制。方法 利用 H-ras12V 转基因雄鼠肝肿瘤组织、肿瘤周围组织以及非转基因雄鼠肝组织进行病理分析和总 RNA 及蛋白质的提取。应用 qRT-PCR 和 Western blot 方法检测 cyclin D1 的表达以及调控 cyclin D1 表达的相关信号通路激活状态。采用 miRNA 测序、生物信息学分析和 qRT-PCR 验证方法检测 miR-5102 基因的表达水平。结果 与非转基因雄鼠肝组 织和肿瘤周围组织相比,肿瘤组织中 cyclin D1 基因的 mRNA 和蛋白表达水平显著升高。与非转基因雄鼠肝组织 和肿瘤周围组织相比,在肿瘤组织中 MAPK 信号转导通路中的 ERK 信号分子的蛋白表达水平和磷酸化水平都显 著升高,在肿瘤组织中成高激活状态,NF-KB 信号通路中的抑制因子 IKB 蛋白水平显著降低。miR-5102 的表达水 平没有显著变化。结论 在 Ras 癌基因诱导的肝肿瘤发生过程中,主要通过激活 MAPK/ERK 和 NF-KB 信号通路促进 cyclin D1 的表达。     

弗氏链霉菌变种S-221产弹性蛋白酶发酵培养基的优化研究

通过对弗氏链霉菌（Streptomyces fiadiae）变种S-221产弹性蛋白酶发酵培养基的优化,以提高该菌株所产的弹性蛋白酶酶活。试验采用单因素与正交试验对发酵培养基的成分进行优化研究。优化后发酵培养基的成分为：果糖6％,干酪素1.5％,碳酸铵0.3％,K2HPO4·3H2O 0.05％。MnSO4·H2O 0.001％。在此条件下该菌所产弹性蛋白酶酶活达到96.63U／mL,优化后的发酵培养基与优化前相比所产弹性蛋白酶酶活提高了30％。     

miRNA-125a靶向调控Bcl-2对癫痫大鼠神经元凋亡的影响

目的 探讨miRNA-125a靶向调控Bcl-2对癫痫大鼠神经元凋亡的影响.方法 选择清洁级SD雄性大鼠32只随机分为正常对照组(A组)、癫痫组(B组)、miRNA-125a antagomir control组(C组)和miRNA-125a antagomir组(D组).qRT-PCR检测各组大鼠脑组织miRNA-1...     

Fault-tolerant control of linear uncertain systems using H∞ robust predictive control

The robust fault-tolerant control problem of linear uncertain systems is studied. It is shown that a solution for this problem can be obtained from a H∞ robust predictive controller （RMPC） by the method of linear matrix inequality （LMI）. This approach has the advantages of both H∞ control and MPC： the robustness and ability to handle constraints explicitly. The robust closed-loop stability of the linear uncertain system with input and output constraints is proven under an actuator and sensor faults condition. Finally, satisfactory results of simulation experiments verify the validity of this algorithm.     

Sliding mode H∞ control for a class of uncertain nonlinear state-delayed systems

A new proportional-integral (PI) sliding surface is designed for a class of uncertain nonlinear state-delayed systems. Based on this, an adaptive sliding mode controller (ASMC) is synthesized, which guarantees the occurrence of sliding mode even when the system is undergoing parameter uncertainties and external disturbance. The resulting sliding mode has the same order as the original system, so that it becomes easy to solve the H_∞ control problem by designing a memoryless H_∞ state feedback controller. A delay-dependent sufficient condition is proposed in terms of linear matrix inequalities (LMIs), which guarantees the sliding mode robust asymptotically stable and has a noise attenuation level γ in an H_∞ sense. The admissible state feedback controller can be found by solving a sequential minimization problem subject to LMI constraints by applying the cone complementary linearization method. This design scheme combines the strong robustness of the sliding mode control with the H_∞ norm performance. A numerical example is given to illustrate the effectiveness of the proposed scheme.     

Delay-dependent robust H∞ control of convex polyhedral uncertain fuzzy systems

The robust H∞ control problem for a class of uncertain Takagi-Sugeno fuzzy systems with timevarying state delays is studied. The uncertain parameters are supposed to reside in a polytope. Based on the delay-dependent Lyapunov functional method, a new delay-dependent robust H∞ fuzzy controller, which depends on the size of the delays and the derivative of the delays, is presented in term of linear matrix inequalities （LMIs）. For all admissible uncertainties and delays, the controller guarantees not only the asymptotic stability of the system but also the prescribed H∞ attenuation level. In addition, the effectiveness of the proposed design method is demonstrated by a numerical example.     

Robust H∞ output feedback controller design for uncertain discrete-time switched systems via switched Lyapunov functions

The H∞ output feedback control problem for uncertain discrete-time switched systems is reasearched. A new characterization of stability and H∞ performance for the switched system under arbitrary switching is obtained by using switched Lyapunov function.Then,based on the characterization,a linear matrix inequality (LMI)approach is developed to design a switched output feedback controller which guarantees the stability and H∞ performance of the closed-loop system.A numerical example is presented to demonstrate the application of the proposed method.