DQIT: /spl mu/-synthesis without D-scale fitting

A new approach called D-Q iteration (DQIT) for synthesizing robust H/sub /spl infin// controllers is proposed to avoid D-scale fitting in D-K iteration (DKIT). Each iteration includes a D-step and a Q-step. In the D-step, the D-scale at each frequency is optimized as in DKIT, but D-scale fitting is not required. In the Q-step, the scaled H/sub /spl infin// problem is approximated by a finite-dimensional Q-parameter optimization problem in the frequency domain, using D-scales directly. Numerical examples show significant improvement in some cases.     

A (/spl mu/ + /spl lambda/) evolutionary algorithm for reconstruction of SPECT data

Algorithms used to reconstruct single photon emission computed tomography (SPECT) data are based on one of two principles: filtered back projection or iterative methods. In this paper, an evolution strategy (ES) was applied to reconstruct transaxial slices of SPECT data. Evolutionary algorithms are stochastic global search methods that have been used successfully for many kinds of optimization problems. The newly developed reconstruction algorithm consisting of /spl mu/ parents and /spl lambda/ children uses a random principle to readjust the voxel values, whereas other iterative reconstruction methods use the difference between measured and simulated projection data. The (/spl mu/ + /spl lambda/)-ES was validated against a test image, a heart, and a Jaszczak phantom. The resulting transaxial slices show an improvement in image quality, in comparison to both the filtered back projection method and a standard iterative reconstruction algorithm.     

Silicon-on-insulator microfluidic device with monolithic sensor integration for /spl mu/TAS applications

A novel concept for the integration of liquid phase charge sensors into microfluidic devices based on silicon-on-insulator (SOI) technology is reported. Utilizing standard silicon processing we fabricated basic microfluidic cross geometries comprising of 5-10-mm-long and 55-/spl mu/m-wide channels of 3 /spl mu/m depth by wet sacrificial etching of the buried oxide of an SOI substrate. To demonstrate the feasibility of fluid manipulation along the channel we performed electroosmotic pumping of a dye-labeled buffer solution. At selected positions along the channel we patterned the 205-nm thin top silicon layer into freely suspended, 10-/spl mu/m wide bars bridging the channel. We demonstrate how these monolithically integrated bars work as thin-film resistors that sensitively probe changes of the surface potential via the field effect. In this way, a combination of electrokinetic manipulation and separation of charged analytes together with an on-chip electronic detection can provide a new basis for the label-free analysis of, for example, biomolecular species as envisaged in the concept of micrototal analysis systems (/spl mu/TAS) or Lab-on-Chip (LOC).     

Stability analysis and H/sub /spl infin// controller design of fuzzy large-scale systems based on piecewise Lyapunov functions

This paper presents a novel approach to stability analysis of a fuzzy large-scale system in which the system is composed of a number of Takagi-Sugeno (T-S) fuzzy subsystems with interconnections. The stability analysis is based on Lyapunov functions that are continuous and piecewise quadratic. It is shown that the stability of the fuzzy large-scale systems can be established if a piecewise Lyapunov function can be constructed, and, moreover, the function can be obtained by solving a set of linear matrix inequalities (LMIs) that are numerically feasible. It is also demonstrated via a numerical example that the stability result based on the piecewise quadratic Lyapunov functions is less conservative than that based on the common quadratic Lyapunov functions. The H/sub /spl infin// controllers can also be designed by solving a set of LMIs based on these powerful piecewise quadratic Lyapunov functions.     

/spl Lscr//sub /spl infin//-multipliers for robust performance analysis

Linear systems subject to nonlinear time-varying sector-bounded uncertainties are considered. Robust performance is measured in terms of the worst-case ratio between the /spl Lscr//sub /spl infin//-norms of the output and input signals. A new class of multipliers is introduced and characterized. The characterization can be used to compute an upper bound for robust performance, which tightens the bound obtained by the scaled small gain theorem. While the standard Popov multipliers and their extensions have been developed within the /spl Lscr//sub 2/ framework, our multipliers are adapted to /spl Lscr//sub /spl infin//.     

Simple method for the design of Lyapunov functionals in distributed-parameter systems

The properties of Lyapunov functionals for systems of partial differential equations are expressed in local form. When written as an identity, the Lagrange multiplier forms the basis of a design method. This is applied to linear and non-linear examples. In the latter case, results are obtained more simply than previously. For ordinary differential equations, the method reduces to a standard one.     

The Lyapunov functionals method in stability problems for functional differential equations

The paper presents a survey of stability results for retarded functional differential equations with the Lyapunov functional method.     

/spl mu/ITRON-LP: power-conscious real-time OS based on cooperative voltage scaling for multimedia applications

This work presents a cooperative dynamic power management method and its implementation. The implementation consists of design of a real-time OS, applications including MPEG-4, and development of a supporting hardware platform with an off-the-shelf processor. We describe several factors that are important in the implementation and discuss its efficiency through experiment. The experimental results with the prototype system shows that 74% power saving is possible in multi-task multimedia environment.     

Lyapunov functionals and Lyapunov matrices for neutral type time delay systems: a single delay case

Quadratic Lyapunov functionals with a given time derivative for the case of neutral type time delay systems have been presented in Rodriguez et al. (“Robust stability of neutral systems: a Lyapunov–Krasovskii constructive approach”, International Journal of Robust and Nonlinear Control, 14, pp. 1345–1358, 2004). In this contribution a new form of the functionals is proposed. The functionals now do not include the time derivative of the system state. This modification provides new quadratic bounds for the functionals and makes them useful in computation of exponential estimates for solutions of the systems, as well as in calculation of the robustness bounds.

Special attention has also been paid to the Lyapunov matrices which define the functionals. A new definition of the matrices is given, and their properties are analysed in detail.     

H/sub /spl infin// state-feedback controller design for discrete-time fuzzy systems using fuzzy weighting-dependent Lyapunov functions

For discrete-time Takagi-Sugeno (TS) fuzzy systems, we propose an H/sub /spl infin// state-feedback fuzzy controller associated with a fuzzy weighting-dependent Lyapunov function. The controller, which is designed via parameterized linear matrix inequalities (PLMIs), employs not only the current-time but also the one-step-past information on the time-varying fuzzy weighting functions. Appropriately selecting the structures of variables in the PLMIs allows us to find an LMI formulation as a special case.     

0.8 /spl mu/m CMOS implementation of weighted-order statistic image filter based on cellular neural network architecture.

In this paper, a very large scale integration chip of an analog image weighted-order statistic (WOS) filter based on cellular neural network (CNN) architecture for real-time applications is described. The chip has been implemented in CMOS AMS 0.8 /spl mu/m technology. CNN-based filter consists of feedforward nonlinear template B operating within the window of 3 /spl times/ 3 pixels around the central pixel being filtered. The feedforward nonlinear CNN coefficients have been realized using programmable nonlinear coupler circuits. The WOS filter chip allows for processing of images with 300 pixels horizontal resolution. The resolution can be increased by cascading of the chips. Experimental results of basic circuit building blocks measurements are presented. Functional tests of the chip have been performed using a special test setup for PAL composite video signal processing. Using the setup real images have been filtered by WOS filter chip under test.     

H/sub /spl infin// controller synthesis of fuzzy dynamic systems based on piecewise Lyapunov functions and bilinear matrix inequalities

This work presents an H/sub /spl infin// controller design method for fuzzy dynamic systems based on techniques of piecewise smooth Lyapunov functions and bilinear matrix inequalities. It is shown that a piecewise continuous Lyapunov function can be used to establish the global stability with H/sub /spl infin// performance of the resulting closed-loop fuzzy control systems and the control laws can be obtained by solving a set of bilinear matrix inequalities (BMIs). Two examples are given to illustrate the application of the proposed methods.     

Stability analysis of interconnected complex nonlinear systems using the Lyapunov and Finsler property

Multimedia Tools and Applications - This study focuses on the question of the stability analysis of complex interconnected nonlinear systems using the property of Lyapunov and Finsler. The main...     

Linear dependency between /spl epsi/ and the input noise in /spl epsi/-support vector regression

In using the /spl epsi/-support vector regression (/spl epsi/-SVR) algorithm, one has to decide a suitable value for the insensitivity parameter /spl epsi/. Smola et al. considered its "optimal" choice by studying the statistical efficiency in a location parameter estimation problem. While they successfully predicted a linear scaling between the optimal /spl epsi/ and the noise in the data, their theoretically optimal value does not have a close match with its experimentally observed counterpart in the case of Gaussian noise. In this paper, we attempt to better explain their experimental results by studying the regression problem itself. Our resultant predicted choice of /spl epsi/ is much closer to the experimentally observed optimal value, while again demonstrating a linear trend with the input noise.     

Robust stability functionals of state delayed systems with polytopic type uncertainties via parameterdependent Lyapunov functions

This paper considers the problem of robust stability for linear systems with a constant time-delay in the state and subject to real convex polytopic uncertainty. Both delay-independent and delay-dependent stability conditions are characterized by linear matrix inequalities which allow the use of parameter-dependent Lyapunov functionals to analyse the system stability against parameter perturbations, and therefore improve the conservativeness resulting from the single Lyapunov functional. In order to determine the maximum of time-delay within which the system remains stable, the problem can be cast into a generalized eigenvalue problem and solved by standard LMI solvers. Two examples are included to illustrate the proposed method.     

/spl epsiv/-insensitive fuzzy c-regression models: introduction to /spl epsiv/-insensitive fuzzy modeling

This paper introduces a new epsilon-insensitive fuzzy c-regression models (epsilonFCRM), that can be used in fuzzy modeling. To fit these regression models to real data, a weighted epsilon-insensitive loss function is used. The proposed method make it possible to exclude an intrinsic inconsistency of fuzzy modeling, where crisp loss function (usually quadratic) is used to match real data and the fuzzy model. The epsilon-insensitive fuzzy modeling is based on human thinking and learning. This method allows easy control of generalization ability and outliers robustness. This approach leads to c simultaneous quadratic programming problems with bound constraints and one linear equality constraint. To solve this problem, computationally efficient numerical method, called incremental learning, is proposed. Finally, examples are given to demonstrate the validity of introduced approach to fuzzy modeling.     

Case study: Darlington nuclear generating station /spl lsqb/software-driven shutdown systems/spl rsqb/

Darlington is a four-reactor nuclear plant east of Toronto. It is operated by Ontario Hydro. Each reactor has two independent shutdown systems: SDS1 drops neutron-absorbing rods into the core, while SDS2 injects liquid poison into the moderator. Both are safety-critical and require high levels of confidence. In 1982, Ontario Hydro, with the concurrence of the Atomic Energy Control Board of Canada (AECB), had decided to fully implement the shutdown systems' decision-making logic on computers. This was to be the first Canadian instance of such a system, so there were questions about what procedures to follow, both in developing and licensing the system. To help achieve certification for the plant's shutdown systems, formal methods were applied to convince the AECB that the code was of acceptable quality and in accordance with specifications. Formal methods, applied only when serious concerns about the adequacy of the software and documentation arose, took the form of a formal model-based inspection.<>     

/spl epsi/-SSVR: a smooth support vector machine for /spl epsi/-insensitive regression

A new smoothing strategy for solving /spl epsi/-support vector regression (/spl epsi/-SVR), tolerating a small error in fitting a given data set linearly or nonlinearly, is proposed in this paper. Conventionally, /spl epsi/-SVR is formulated as a constrained minimization problem, namely, a convex quadratic programming problem. We apply the smoothing techniques that have been used for solving the support vector machine for classification, to replace the /spl epsi/-insensitive loss function by an accurate smooth approximation. This will allow us to solve /spl epsi/-SVR as an unconstrained minimization problem directly. We term this reformulated problem as /spl epsi/-smooth support vector regression (/spl epsi/-SSVR). We also prescribe a Newton-Armijo algorithm that has been shown to be convergent globally and quadratically to solve our /spl epsi/-SSVR. In order to handle the case of nonlinear regression with a massive data set, we also introduce the reduced kernel technique in this paper to avoid the computational difficulties in dealing with a huge and fully dense kernel matrix. Numerical results and comparisons are given to demonstrate the effectiveness and speed of the algorithm.     

l/sup /spl infin//-bounded robustness for nonlinear systems: analysis and synthesis

The purpose of this paper is to describe systematic analysis and design tools for robust control problems with l/sup /spl infin// criteria. We first generalize the Hill-Moylan-Willems framework for dissipative systems to accommodate l/sup /spl infin// criteria, and then derive state feedback and measurement feedback synthesis procedures for l/sup /spl infin// robust control problems. The information state framework is used for the measurement feedback robust control problem. Necessary and sufficient conditions are proved, and new synthesis procedures using dynamic programming are presented.