A methodology and model for the pull-in parameters of magnetostatic actuators

Magnetostatic actuators exhibit bistability similarly to the pull-in phenomena of electrostatic actuators. In this paper a methodology and model for the extraction of the magnetic Pull-In parameters of magnetostatic actuators are derived. The flux-controlled magnetostatic actuator is analyzed based on the energy representation and the magnetomotive force-controlled magnetostatic actuator is analyzed in the thermodynamic potential energy (or co-energy) representation. An algebraic equation, referred to as the magnetic Pull-In equation, for each of the two cases (flux-controlled and magnetomotive force-controlled actuators) is derived. By solving these Pull-In equations either analytically or numerically, the magnetic Pull-In parameters are obtained. Several case studies, covering displacement and torsion magnetic actuators, are presented and analyzed, illustrating the usefulness of the proposed methodology, its relative simplicity as well as the adaptability and practical usage in wide spectrum of magnetic actuators. [1425].     

On the reduction in multiplicative complexity achieved by thepolynomial residue number system

The polynomial residue number system is known to reduce the complexity of polynomial multiplication from O(N² ) to O(N). A new interpretation of this complexity reduction is given in the context of associative algebras over a finite field. The new point of view provides a clearer understanding of the Chinese remainder theorem     

Maximum-likelihood estimation of circle parameters via convolution.

The accurate fitting of a circle to noisy measurements of circumferential points is a much studied problem in the literature. In this paper, we present an interpretation of the maximum-likelihood estimator (MLE) and the Delogne-K?sa estimator (DKE) for circle-center and radius estimation in terms of convolution on an image which is ideal in a certain sense. We use our convolution-based MLE approach to find good estimates for the parameters of a circle in digital images. In digital images, it is then possible to treat these estimates as preliminary estimates into various other numerical techniques which further refine them to achieve subpixel accuracy. We also investigate the relationship between the convolution of an ideal image with a "phase-coded kernel" (PCK) and the MLE. This is related to the "phase-coded annulus" which was introduced by Atherton and Kerbyson who proposed it as one of a number of new convolution kernels for estimating circle center and radius. We show that the PCK is an approximate MLE (AMLE). We compare our AMLE method to the MLE and the DKE as well as the Cramér-Rao Lower Bound in ideal images and in both real and synthetic digital images.     

The role of cue salience in the development of time concepts: Duration comparisons in young children.

It has been claimed that in the course of developing time concepts, young children go through a stage in which they conceptualize duration as being dependent on endings of events rather than on beginnings and endings. This conceptual deficit was proposed to account for children's greater success in comparing durations that differ in their endings than durations that differ in their beginnings. The present study analyzes the possibility that this phenomenon may be attributed mainly to perceptual salience rather than to conceptual deficit. 360 children from nursery school, kindergarten, and 1st grade were asked to compare the burning times of 2 lights that started and/or ended simultaneously. The role of attention to beginning vs end points in duration judgment was investigated by manipulating beginning- vs end-point salience via systematic variations of sequence of the problems presented. Correct comparisons of duration problems were found to be a function of the relative salience of beginning vs end points. Results support the salience attention model rather than the conceptual deficit account of duration judgments of young children. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of dimensional salience and salience of variability on problem solving: A developmental study.

Presented a matching task to 120 6-20 yr olds to investigate the relative influence of dimensional salience and salience of variability on problem solving. The task included 4 dimensions: form, color, number, and position. On each problem, 1 dimension was relevant and the other 3, which could be either constant or variable, were irrelevant for solution. Ss were asked to find which of 2 stimuli was more similar to a standard stimulus. Results show the same dimensional hierarchy for both reaction time and error scores. The effect of variability, as measured by reaction time and error scores, increased with increasing number of variable irrelevant dimensions and decreased with age. The effect of variability proved to be greater than the effect of dimensions. The implications of the relative influence of dimensional salience and salience variability for problem solving are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)