Exponential quasi‐(Q,S,R)‐dissipativity and practical stability for switched nonlinear systems

In this paper, the problems of exponential quasi‐(Q,S,R)‐dissipativity and practical stability analysis for a switched nonlinear system are addressed. First, the concept of exponential quasi‐(Q,S,R)‐dissipativity for switched nonlinear systems without requiring the exponential quasi‐(Q,S,R)‐dissipativity property of each subsystem is proposed. Then, we show that an exponentially quasi‐(Q,S,R)‐dissipative switched nonlinear system is practically stable. Second, this exponential quasi‐(Q,S,R)‐ dissipativity property for a switched nonlinear system is obtained by the design of a state‐dependent switching law. Third, a composite state‐dependent switching law is designed to render the feedback interconnection of switched nonlinear systems exponentially quasi‐(Q,S,R)‐dissipative. This switching law allows interconnected switched nonlinear systems to switch asynchronously. Finally, the effectiveness of the results is verified by a numerical example.     

Geometrically (Q,S, R)‐Incremental Dissipativity and Incremental Stability for Switched Time‐Varying Nonlinear Discrete‐Time Systems

This paper investigates geometrically (Q,S,R)‐incremental dissipativity and incremental stability for switched time‐varying nonlinear discrete‐time systems. A geometrically (Q,S,R)‐incremental dissipativity concept is proposed for switched nonlinear discrete‐time systems by using multiple storage functions and multiple incremental supply rate. Furthermore, the sufficient conditions of geometrically (Q,S,R)‐incremental dissipativity are given under the design of state‐dependent switching law. The incremental stability conditions are derived for geometrically (Q,S,R)‐incrementally dissipative switched systems. By designing of a composite state‐dependent switching law, the feedback interconnected switched systems are ensured to be geometrically (Q,S,R)‐incrementally dissipative. A numerical example is given to illustrate the validity of the proposed approach.     

Highly efficient blue organic light‐emitting diode with high color purity using 4,4′‐N,N′‐dicarbazole‐biphyenyl (CBP) doped with 1,4‐bis[2‐(3‐N‐ethylcarbazoryl) vinyl]benzene (BCzVB)

Abstract— An efficient pure blue multilayer organic light‐emitting diode employing 1,4‐bis[2‐(3‐N‐ethylcarbazoryl)vinyl]benzene (BCzVB) doped into 4,4′‐N,N′‐dicarbazole‐biphyenyl (CBP) is reported. The device structure is ITO (indium tin oxide)/TPD (N,N′‐diphenyl‐N,N′‐bis (3‐methylphenyl)‐1,1′biphenyl‐4,4′diamine)/CBP:BCzVB/Alq₃ (tris‐(8‐hydroxy‐quinolinato) aluminum)/Liq (8‐hydroxy‐quinolinato lithium)/Al; here TPD was used as the hole‐transporting layer, CBP as the blue‐emitting host, BCzVB as the blue dopant, Alq₃ as the electron‐transporting layer, Liq as the electron‐injection layer, and Al as the cathode, respectively. A maximum luminance of 8500 cd/m² and a device efficiency of 3.5 cd/A were achieved. The CIE co‐ordinates were x = 0.15, y = 0.16. The electroluminescent spectra reveal a dominant peak at 448 nm and additional peaks at 476 nm with a full width at half maximum of 60 nm. The Föster energy transfer and, especially, carrier trapping models were considered to be the main mechanism for exciton formation on BCzVB molecules under electrical excitation.     

On mean‐square H∞ control for discrete‐time nonlinear stochastic systems with (x,u, v)‐dependent noises

In this paper, the H_∞ control problem is investigated for a general class of discrete‐time nonlinear stochastic systems with state‐, control‐, and disturbance‐dependent noises (also called (x, u, v)‐dependent noises). In the system under study, the system state, the control input, and the disturbance input are all coupled with white noises, and this gives rise to considerable difficulties in the stability and H_∞ performance analysis. By using the inequality techniques, a sufficient condition is established for the existence of the desired controller such that the closed‐loop system is mean‐square asymptotically stable and also satisfies H_∞ performance constraint for all nonzero exogenous disturbances under the zero‐initial condition. The completing square technique is used to design the H_∞ controller with hope to reduce the resulting conservatism, and a special algebraic identity is employed to deal with the cross‐terms induced by (x, u, v)‐dependent noises. Several corollaries with simplified conditions are presented to facilitate the controller design. The effectiveness of the developed methods is demonstrated by two numerical examples with one concerning the multiplier‐accelerator macroeconomic system.     

Identification Recurrent Type 2 Fuzzy Wavelet Neural Network and L2‐Gain Adaptive Variable Sliding Mode Robust Control of Electro‐Hydraulic Servo System (EHSS)

An electro‐hydraulic servo system (EHSS) is a kind of system with the characteristics of time‐variant, serious nonlinearity, parameter and structural uncertainty, and uncertain load disturbance in most cases. These characteristics make it very difficult to realize highly accurate control by conventional methods. In order to solve the above problems, this paper introduces a recurrent type 2 fuzzy wavelet neural network to approximate the unknown nonlinear functions of the dynamic systems through tuning by the desired adaptive law. Based on the identification by recurrent type 2 fuzzy wavelet neural network, a L2 gain design method, combining gain adaptive variable sliding mode control with H infinity control, is proposed for load disturbance, thereby accommodating uncertainties that are the main factors affecting system stability and accuracy in EHSS. In this algorithm, a recurrent type 2 fuzzy wavelet neural network is employed to evaluate the unknown dynamic characteristics of the system and gain adaptive variable sliding mode control to compensate for evaluating errors, and H infinity control to suppress the effect on system by load disturbance. The experiment results show that the proposed system L2 gain design method can make the system exhibit strong robustness to parameter variation and load disturbance.     

Synthesis and characterization of bis‐(8‐hydroxyquinoline) strontium (SrQ2) in water medium

One‐dimensional nanowires of 8‐hydroxyquinoline strontium (SrQ₂‐1) was synthesized by liquid phase method. The structure and composition of the products were analyzed by X‐ray diffraction (XRD), Fourier transform infrared (FTIR) absorption spectroscopy, and X‐ray photoelectron spectroscopy (XPS), indicating that 8‐hydroxyquinoline strontium was successfully synthesized. The fluorescence properties of SrQ₂‐1 were analyzed by fluorescence spectra; the results showed that the maximum emission wavelength was detected at 473 nm (blue light area), the fluorescence lifetime of SrQ₂‐1 is 7.38 nanoseconds, and the fluorescence quantum yield is 28.3%. The analysis of TG‐DSC diagram suggests that SrQ₂‐1 begins to decompose at 475°C, which indicates SrQ₂‐1 has good thermal stability. Consequently, 8‐hydroxyquinoline strontium can be used as a blue luminescent material.     

H∞ Static Output Feedback Control of 2‐D Discrete Systems in FM Second Model

The problem of H_∞ static output feedback (SOF) control of two‐dimensional (2‐D) discrete systems described by the Fornasini‐Marchesini (FM) second model is investigated in this paper. First, by applying the 2‐D Bounded Real Lemma, the 2‐D H_∞ SOF control problem is formulated in terms of a bilinear matrix inequality (BMI). Then, by combining the slack variable technique with two kinds of existing LMI methods, respectively, less conservative sufficient LMI conditions are proposed for the BMI formulation. The relation of these two kinds of LMI conditions are revealed by analyzing the choices of coordinate transformation matrices involved in the first kind of LMI conditions. Finally, a numerical example is provided to demonstrate the effectiveness and merits of the proposed methods.     

Study on general stability and stabilizability of linear discrete‐time stochastic systems

With the aid of spectrum technique, a new concept called “ ??(0, α)‐stabilizability” (0<α≤1) is introduced, for which a necessary and sufficient condition is also proposed via a linear matrix inequality (LMI)‐based approach. Especially, ??(0, α)‐stabilizability is identical with asymptotic mean square stabilizability when α=1. A more general regional stability called “ ??_R‐stability” is discussed extensively and some concrete examples are given. As applications, the relationship among ??(0, α;β)‐stability, the decay rate of the system state response and the second‐order moment Lyapunov exponent is revealed. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

The binomial decomposition of OWA functions,the 2‐additive and 3‐additive cases in n dimensions

In the context of the binomial decomposition of ordered weighted averaging (OWA) functions, we investigate the constraints associated with the 2‐additive and 3‐additive cases in n dimensions. The 2‐additive case depends on one coefficient whose feasible region does not depend on the dimension n. On the other hand, the feasible region of the 3‐additive case depends on two coefficients and is explicitly dependent on the dimension n. This feasible region is a convex polygon with n vertices and n edges, which is strictly expanding in the dimension n. The orness of the OWA functions within the feasible region is linear in the two coefficients, and the vertices associated with maximum and minimum orness are identified. Finally, we discuss the 3‐additive binomial decomposition in the asymptotic infinite dimensional limit.     

Thymosin β4 is differentially expressed in the cerebrospinal fluid of Creutzfeldt‐Jakob disease patients: a MALDI‐TOF MS protein profiling study

MALDI‐TOF protein profiling analysis permits the detection of peptides and small proteins in complex protein mixtures with great accuracy. We applied this analysis to cerebrospinal fluid (CSF) from 15 patients affected by Creutzfeldt‐Jakob disease (CJD). We compared the levels of the normalized ion signals of 11 sporadic and 4 genetic CJD forms with those from ten healthy control subjects and eight non‐CJD relapsing‐remitting multiple sclerosis patients. In so doing, we detected 61 differentially expressed ion signals in CJD samples compared to controls. Among the 61 signals, 3 signals had significantly increased levels with high statistical significance (p <0.0001) and were located at 3238.3 m/z, 4963.7 m/z, and 8565.3 m/z. We characterized the 5.0 and 8.6 kDa proteins as thymosin β4 N‐acetylated and free ubiquitin, respectively, while the 3.2‐kDa peptide remained uncharacterized. Although elevated ubiquitin levels have previously been described in CJD, we have demonstrated for the first time the involvement of thymosin β4 in a neurodegenerative disease. To support the validity of thymosin β4 levels obtained by MALDI‐TOF analysis, an independent enzyme immunoassay analysis was performed. Moreover, a validation cohort consisting of CSF from three CJD patients, five healthy subjects, and six non‐CJD relapsing‐remitting multiple sclerosis patients was analyzed in a similar way, yielding superimposable results. We propose that thymosin β4 is a potential new candidate marker for the ante mortem diagnosis of CJD disease.     

Development of “H‐Shaped” monopole antenna for IEEE 802.11a and HIPERLAN 2 applications in the laptop computer

A very low profile and ultra‐thin “H‐Shaped” antenna for IEEE 802.11a and HIPERLAN 2 wireless applications in the laptop computer is developed. The antenna is designed using only a pure copper strip of size 17.5(L) × 4(W) mm² with thickness of only 0.035 mm. The novelty of the proposed antenna is that the antenna is designed with only one rectangular radiating strip without using any additional reactive components, vias or three dimensional structure. Furthermore, the proposed antenna does not require any additional ground plane for installing in laptops. The proposed antenna is comprised of one radiating strip, one rectangular stub, and two resonating slots, namely, “X” and “Y” of length 7.5 mm and 7 mm, respectively. The proposed structure resonates at around 5.5 GHz can cover the (5.15‐5.35/5.725‐5.825) GHz IEEE 802.11a and (5.15‐5.35/5.470‐5.725/5.725‐5.925) GHz HIPERLAN 2 bands. The fabricated prototype antenna has measured impedance bandwidth (VSWR<2) of 15% (5.10‐5.92 GHz) across the operating bands. The measured radiation patterns are nearly omnidirectional along with stable gain of 5 dBi. Moreover, the proposed antenna exhibits excellent radiation efficiency of around 90% across the operating bands. The simulated and measured results of antenna are found to be in good agreement. The very low profile and ultra‐thin structure make it an excellent candidate for wireless operations in the ultra‐thin laptop computers.     

MinT—Architecture and applications of the (t, m, s)-net and OOA database

Many different constructions for (t,m,s)$(t\text{,}m\text{,}s)$-nets and (t,s)$(t\text{,}s)$-sequences are known today. Propagation rules as well as connections to other mathematical objects make it difficult to determine the best net available in a given setting.