A microwave doppler technique for vehicle speed determination

Conventional Microwave Doppler Speed Measurement systems have long been considered unusable in many situations. In this dissertation a novel technique for speed measurement is presented which eliminates some of the problems associated with conventional systems, in particular the problem of vehicle identification. It is shown how a 'capture area' may be defined. Only the speeds of vehicles within the capture area are measured. A prototype speed measuring instrument was designed and constructed. The instrument was shown to work as predicted and the the notion of the 'capture area' was proved

Interactive speech-driven facial animation

One of the fastest developing areas in the entertainment industry is digital animation. Television programmes and movies frequently use 3D animations to enhance or replace actors and scenery. With the increase in computing power, research is also being done to apply these animations in an interactive manner. Two of the biggest obstacles to the success of these undertakings are control (manipulating the models) and realism. This text describes many of the ways to improve control and realism aspects, in such a way that interactive animation becomes possible. Specifically, lip-synchronisation (driven by human speech), and various modeling and rendering techniques are discussed. A prototype that shows that interactive animation is feasible, is also described.Mr. A. Hardy Prof. S. von Solm

Digital Filtering and Processing by Transform Techniques, Volume 1 Final Report

Digital filtering and processing by transform technique

Electron collision effects on radar temperature measurements of the ionosphere

Most plasmas in astrophysics are hot, tenuous gases where macroscopic electric and magnetic fields dominate the plasma dynamics. In the Earth’s ionosphere the plasma is cold and dense, and the small-scale Coulomb force between charged particles becomes important. In this dissertation I implement a grid-based Coulomb collision algorithm in the Electrostatic Parallel Particle-in-Cell (EPPIC) simulator to model spectra observed by incoherent scatter radars (ISR). The modeled spectra are then compared to observations from Millstone Hill to show that current radar techniques can systematically underestimate plasma temperatures in the ionosphere. ISRs transmit radio waves that are Thomson scattered by electrons in the ionosphere, and then measure the Doppler shift spectra off the ion-acoustic wave. The measured spectra are then fit to a forward model in order to estimate altitude profiles of plasma density, electron temperature, ion temperature, and ion drift speed. For radars looking at aspect angles within 5° of perpendicular to the Earth’s magnetic field, the magnetic field constrains electron movement and Coulomb collisions add an additional source of damping that narrows the spectral width. Fitting the collisionally narrowed spectra to collisionless theories leads to underestimates of plasma temperatures by as much as 25%. Using EPPIC, I present the first fully kinetic, self-consistent, particle-in-cell simulations of ISR spectra with electron-ion and electron-electron Coulomb collisions. For intermediate aspect angles between 0.5° and 2° off perpendicular, the damping effects of electron-ion and electron-electron collisions are the same and the resulting spectra are narrower than what current theories predict. For aspect angles larger than 3° away from perpendicular, the simulations with electron-ion collisions match collisionless ISR theory well, but spectra with electron-electron collisions are narrower than theory predicts at aspect angles as large as 5° away from perpendicular. I use the Millstone Hill radar to measure spectra at small aspect angles and show that current theories produce incorrect temperature measurements at aspect angles of 4.6° or less. The EPPIC simulations show that a nonlinear interaction between electron-electron collisions and Landau damping causes the errors in temperature measurement, which is not accounted for in current theories

A real time Fast Fourier Transform analyser

From the requirements of the Ionosonde digitisation project, undertaken by Rhodes University Antarctic Research Group, it was decided to use the Fast Fourier Transform to compute the spectrum analysis. Several FFT algorithms are reviewed and properties discussed, and the Ccoley Tukey algorithm chosen for utilization. The hardware implementation of this algorithm, and the microprogram control of the whole system are discussed in detail, and such design aspects that required computer simulation are also treated in detail. The final testing of the analyser is shown, and includes a test using data from an ionosonde sounding. The conclusions contain details of extensions to the analysers present operation, required by plans to place the whole Chirpsounder under microprocessor contro

Acoustic emission signal analysis

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.An extension of acoustic emission technology was made which permits identification of probable source mechanisms for signals emitted during the failure of metals. This was achieved through the construction of a unique instrument and the development of special computer programs. The instrument permitted wideband digital waveform recordings to be made of both acoustic emission signals generated during the failure of a specimen, as well as calibration signals derived from a helium gas jet. These recordings were then processed by the computer programs to yield power spectra insensitive to specimen geometry, thus allowing the direct comparison of acoustic emissions from different specimens. A series of experiments conducted to test the instrument and the programs resulted in the conclusion that, at the 95% confidence level, acoustic emission caused by brittle particle fracture in 7039 aluminum could be differentiated from acoustic emission caused by the discontinuous movement of a crack in 4340 steel. Detailed descriptions of acoustic emission source modeling, transducer operating principles, calibration techniques and digital signal processing provide the necessary theoretical background for the reported technology extension, while a comprehensive review of the literature of acoustic emission places the experimental work into the proper context.This study is funded by the Naval Air Development Center, Warminster, Pennsylvania