Novel switched-capacitor generalised integrator

A novel circuit arrangement is proposed for a generalised integrator using the switched-capacitor (SC) technique. This generalised integrator (which integrates with respect to a dependent variable) can easily be constructed in IC form using MOS technology. It possesses some attractive features, for instance simplicity and low cost. It can find applications in many analogue systems such as curve-fitting devices, adaptive filters, RMS convertors etc.     

An iterative inversion approach to blind source separation

We present an iterative inversion (II) approach to blind source separation (BSS). It consists of a quasi-Newton method for the resolution of an estimating equation obtained from the implicit inversion of a robust estimate of the mixing system. The resulting learning rule includes several existing algorithms for BSS as particular cases giving them a novel and unified interpretation. It also provides a justification of the Cardoso and Laheld (1996) step size normalization. The II method is first presented for instantaneous mixtures and then extended to the problem of blind separation of convolutive mixtures. Finally, we derive the necessary and sufficient asymptotic stability conditions for both the instantaneous and convolutive methods to converge.     

Synthetic bioabsorbable microtubes for the treatment of surgical sites

Bioabsorbable polyglycolide-co-lactide microtubes have been developed for the continuous delivery of fluid medications directly to an operative site. Studies conducted with radio-opaque solution using porcine models indicated that infusion of fluids in the wound site was rapid and complete. The tissue reaction to the microtube was generally characterized as minimal to mild with complete absorption occurring within 56 days postimplantation. Processing–microstructure-property relationships and bio-degradation characteristics of the microtubes are presented.     

Geographic Variation in Acadian French /r /: What Can Correspondence Analysis Contribute Toward Explanation?

This article presents elements of a Correspondence Analysis(CA) approach to the measurement of linguistic distances indialectology. It argues that both linguistic and spatial factorsare part of an explanation of geolinguistic variation, and itshows how the exploratory and graphical properties of CA cancontribute to such an explanation. The application is a studyof the different realizations of the phoneme /r/ in AcadianFrench, a dialect spoken in Canada. Data are from the Atlaslinguistique du vocabulaire maritime acadien and include over5,000 tokens from eighteen localities. Using chi-square distances,the analysis results in a two-dimensional space that arrangesthe localities along continua. Linguistic interpretation ofthis space, based on those features of /r/ that are identifiedas accounting for the structuring of these continua, suggestsa hierarchy of phonological processes—including alternationbetween apical and dorsal articulations (in French words), andreplacement of the retroflex rhotic found in English-originwords by apical and dorsal variants. Two external spatial factors,local concentration of francophone speakers and spheres of activity,are shown to correlate with the linguistic distances among localities.     

Kernel PCA for Feature Extraction and De-Noising in Nonlinear Regression

In this paper, we propose the application of the Kernel Principal Component Analysis (PCA) technique for feature selection in a high-dimensional feature space, where input variables are mapped by a Gaussian kernel. The extracted features are employed in the regression problems of chaotic Mackey–Glass time-series prediction in a noisy environment and estimating human signal detection performance from brain event-related potentials elicited by task relevant signals. We compared results obtained using either Kernel PCA or linear PCA as data preprocessing steps. On the human signal detection task, we report the superiority of Kernel PCA feature extraction over linear PCA. Similar to linear PCA, we demonstrate de-noising of the original data by the appropriate selection of various nonlinear principal components. The theoretical relation and experimental comparison of Kernel Principal Components Regression, Kernel Ridge Regression and ε-insensitive Support Vector Regression is also provided.     

Nested-feedback-loops realization of 2-D systems

Algorithms are derived for representation of double power series by branched continued fractions. Some properties of the branched continued fractions are given. Two new alternative structures for realization of a two-dimensional, zero memory nonlinear transfer characteristic are proposed. These structures permit the design of 2-D systems with relatively low sensitivity of the transfer function to coefficient errors. Generalized equivalence transformations of branched continued fractions are also presented. Illustrative examples are included.     

Analysis of active ladder network by using coates flow graphs and continuants

A simple method for solving the matrix equation describing the general active ladder network, is presented. Using Coates flow graphs and continuants the expressions for current, voltage, and also example of application are given.     

Monolithic MOS switched-capacitor microsystems for nonlinear analogsignal processing

A novel nonlinear signal processor (converter) concept suitable for MOS switched-capacitor (SC) system applications is presented. The method is based on time-division and sampling principles. Standard stray-insensitive, offset-compensated MOS SC subcircuits are used as building blocks. A wide variety of nonlinear converters such as multipliers, dividers, squares, higher-power-function generators, logarithmic-, exponential-, and trigonometric-function converters, and many others with special algebraic operations can be easily synthesized. The circuits offer high accuracy and low cost. Experimental results for some important converters are presented