The efficient calculation of the transport properties of a dilute gas to a prescribed accuracy

Numerical techniques for minimizing computation time for determining transport properties of dilute ga

Initial Design and Quick Analysis of SAW Ultra–Wideband HFM Transducers

This paper presents techniques for initial design and quick fundamental and harmonic operation analysis of surface acoustic waves ultra–wideband hyperbolically frequency modulated (HFM) interdigital transducer (IDT). The primary analysis is based on the quasi–static method. Quasi–electrostatic charge's density distribution was approximated by Chebyshev polynomials and the method of Green’s function. It assesses the non uniform charge distribution of electrodes, electric field interaction and the end effects of a whole transducer. It was found that numerical integration (e.g. Romberg, Gauss–Chebyshev) requires a lot of machine time for calculation of the Chebyshev polynomial and the Green’s function convolution when integration includes coordinates of a large number of neighboring electrodes. In order to accelerate the charge density calculation, the analytic expressions are derived. Evaluation of HFM transducer fundamental and harmonics' operation amplitude response with simulation single–dispersive interdigital chirp filter structure is presented. Elapsed time of HFM IDT with 589 electrodes simulations and 2000 frequency response point is only 54 seconds (0.027 s/point) on PC with CPU Intel Core I7–4770S. Amplitude response is compared with linear frequency modulated (LFM) IDT response. It was determined that the HFM transducer characteristic is less distorted in comparison with LFM transducer

Image correlation and sampling study

The development of analytical approaches for solving image correlation and image sampling of multispectral data is discussed. Relevant multispectral image statistics which are applicable to image correlation and sampling are identified. The general image statistics include intensity mean, variance, amplitude histogram, power spectral density function, and autocorrelation function. The translation problem associated with digital image registration and the analytical means for comparing commonly used correlation techniques are considered. General expressions for determining the reconstruction error for specific image sampling strategies are developed

A COMPUTER AIDED APPROACH TO THE NOISE ANALYSIS OF RC AND OPERATIONAL AMPLIFIER NETWORKS

A noise analysis algorithm and computer program is presented which is based on a relationship between the sensitivity of a network function to variations in the value of an element within the network and the noise associated with that element. The program can handle second order RC-operational amplifier networks and will compute the output noise over the user specified bandwidth. The voltage transfer function of the network is also computed. An infinite gain multiple feedback LP filter is analyzed and the results compared with another method

Probabilistic constraint reasoning with Monte Carlo integration to robot localization

This work studies the combination of safe and probabilistic reasoning through the hybridization of Monte Carlo integration techniques with continuous constraint programming. In continuous constraint programming there are variables ranging over continuous domains (represented as intervals) together with constraints over them (relations between variables) and the goal is to find values for those variables that satisfy all the constraints (consistent scenarios). Constraint programming “branch-and-prune” algorithms produce safe enclosures of all consistent scenarios. Special proposed algorithms for probabilistic constraint reasoning compute the probability of sets of consistent scenarios which imply the calculation of an integral over these sets (quadrature). In this work we propose to extend the “branch-and-prune” algorithms with Monte Carlo integration techniques to compute such probabilities. This approach can be useful in robotics for localization problems. Traditional approaches are based on probabilistic techniques that search the most likely scenario, which may not satisfy the model constraints. We show how to apply our approach in order to cope with this problem and provide functionality in real time

The admittance of the infinite cylindrical antenna in a lossy, isotropic, compressible plasma

Numerical values for admittance of infinite cylindrical antenna in lossy, isotropic, compressible plasm