This thesis introduces an alternative potentially low cost solution for hardware-in-the-loop (HIL) simulation based on the waveform relaxation (WR) method. The WR tech-nique is extended so that, without the need for a real-time simulator, the behaviour of an actual piece of physical hardware can nevertheless be tested as though it were connected to a large external electrical network. This is achieved by simulating the external network on an off-line electromagnetic transients (EMT) simulation program, and utilizing iterative exchange of waveforms between the simulation and the hardware by means of a spe-cialized Real-Time Player/Recorder (RTPR) interface device. The approach is referred to as waveform relaxation based hardware-in-the-loop (WR-HIL) simulation. To make the method possible, the thesis introduces several new innovations for stabi-lizing and accelerating the WR-HIL algorithm. It is shown that the classical WR shows poor or no convergence when at least one of the subsystems is an actual device. The noise and analog-digital converters’ quantization errors and other hardware disturbances can affect the waveforms and cause the WR to diverge. Therefore, the application of the WR method in performing HIL simulation is not straightforward and the classical WR need to be modified accordingly. Three convergence techniques are proposed to improve the WR-HIL simulation con-vergence. Each technique is evaluated by an experimental example. The stability of the WR-HIL simulation is studied and a stabilization technique is proposed to provide suffi-cient conditions for the simulation stability. The approach is also extended to include the optimization of the parameters of power system controllers located in geographically distant places. The WR-HIL simulation technique is presented with several examples. At the end of the thesis, suggestions for the future work are presented. / February 2016

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / For simpler implementations of ultra high bit rate systems, combined analog/digital techniques, described here in, provide implementations with the smallest number of component count utilizing minimal “real-estate” and smallest DC power. While digital implementations with tradition Read Only Memory (ROM) and Digital to Analog Converters (DAC’s) have been proven in several commercial, NASA -CCSDS recommended, and U.S. DoD-IRIG standardized Feher’s QPSK (FQPSK) [2,3] products, such implementations can be further simplified, and in particular for ultra high bit rate product applications. Several waveform generating techniques such as linear approximation, analog approximation and mixed analog and linear approximations are investigated using preliminary simulation results.

The objective of this research is to develop and demonstrate low-complexity, robust, frequency-scalable, wide-band waveform acquisition techniques for testing high speed com- munication systems. High resolution waveform capture is a versatile testing tool that enables flexible test strategies. However, waveform capture at high data rates requires costly hardware because the increased bandwidth of the signal waveform leads to an increase in the sampling rate requirement, cost of front-end components, and sensitivity to phase errors in traditional (source) synchronous Nyquist-rate tester architectures. The hardware cost and complexity of wide-band waveform acquisition systems can, however, be significantly reduced by using (trigger-free) incoherent undersampling to achieve reduced sampling rates and robustness to phase errors in signal paths. Reducing the hardware cost of such a system using incoherent undersampling requires increased signal processing at the back end. This research proposes computationally-efficient, time-domain waveform reconstruction algorithms to improve both performance, and scope of existing incoherent undersampling- based test instrumentation. Supporting hardware architectures are developed to extend the application of incoherent undersampling-based waveform acquisition techniques to linearity testing of high-speed radio-frequency components without any synchronization between the signals involved, and to the acquisition of wide-band signals beyond the track-and-hold bandwidth barrier of the traditional incoherent undersampling architectures, using multi-channel bandwidth interleaving. The bandwidth is extended in a source-incoherent framework by using mixers to down convert high-frequency signal components to base band followed by digitization using undersampling, and back-end signal processing to reconstruct the original wide-band signal from multiple band-pass components.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / This paper describes the technology on transmitting a single super fast waveform signal in real-time and introduces the general situation of the telemetry transmitter in vehicle. The equipment is a FM system in view of RF frequency, it is a pulse system in view of RF power. This equipment can transfer not only super fast waveform signals but also slowly varying conventional telemetry signals. The design is very novel. It is a multi-usage telemetry transmitter in vehicle.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / This paper describes the development and test results of a Frequency Modulated Continuous Wave (FMCW) L-Band radar testbed designed to detect obstacles in the proximity of an Unmanned Aerial Vehicle (UAV). From laboratory loopback tests, it was calculated that with pulse compression and a transmit power of 150 mW (22 dBm), the radar is capable of detecting an object with a 0.014-m2 radar cross-sectional area at ranges between 500 ft to 1 mi. Analysis shows that post processing of the collected data would reveal information about the obstacle such as its range and location relative to the aircraft. Design and testing procedures are discussed.

Compliant (flexible) structures play an important role in several biofluid problems including flow in the lungs, heart and arteries. Atherosclerosis is a vascular disease which causes a remodelling of the arterial wall causing a restriction (stenosis) by thickening the intima and the formation of vascular plaque by the deposit of fatty materials. This remodelling alters the compliance of the artery stiffening the arterial wall locally. A common location for this to occur is in the carotid artery which supplies blood to both the brain and the face. It can lead to complete occlusion of the artery in the extreme case and is a major cause of stroke and ischemic infarction. Stroke is the third largest cause of death in the U.S.A., but even if not fatal it can cause coma, paralysis, speech problems and dementia. Atherosclerosis causes a change in the local hemodynamics. It can produce areas of flow separation and low wall shear stress, which can lead to endothelial dysfunction and to promotion of plaque growth. In-vitro modelling with artificial flow phantoms allows the fluid mechanics of the circulatory system to be studied without the ethical and safety issues associated with animal and human experiments. Extensive work has been performed using both experimental and computational techniques to study rigid models representing the arterial system. Computational methods, in which the equations governing the flow and the elastic walls are coupled, are maturing. There is a lack of experimental data in compliant arterial systems to validate the numerical predictions. This thesis sets out to address the problems associated with the in vitro experimental analysis of compliant structures representing the human vasculature. A novel construction technique that produced idealised compliant geometries representing both a healthy and stenosed carotid artery from transparent silicone material was developed. A complete analysis was performed of the circumferential and longitudinal response of the geometry, which allowed for dynamic similarity between in vitro and in vivo conditions to be achieved. Inherent difficulties associated with thin walled phantom construction were overcome, which included the design of a novel endplate that allowed for a smooth transition from the flow system to the flow phantom and a bottom up silicone injection system that ensured the phantom was free of bubbles. The final phantom evolution had a wall thickness that could be produced to within a tolerance of 5%. The constructed flow phantom was ported to a flow system producing a physiological inlet flow waveform scaled to in vitro conditions via Reynolds and Womersley number matching. Experimental analysis was performed using a laser based optical technique, particle image velocimetry (PIV). A novel Light Emitting Diode (LED) illumination system was also implemented to obtain to obtain high speed planar PIV measurements. The combined set up of the LED light source, driver unit components and fibre optics for high speed imaging costs in the region of $US 650 which provides a far cheaper option in comparison to the pulse laser system (In the region of $US 50,000). Results obtained in the healthy geometry were compared to a rigid geometry with the same dimensions. It was found that compliance reduced the peak velocity experienced. It also caused a reduction in wall shear stress (WSS) observed and acted to ameliorate the magnitude of the WSS. This is physiologically significant as high WSS can promote atherosclerosis. The introduction of a stenosis caused an increase in the peak velocity observed over the cardiac cycle. A large increase in WSS can be seen to occur in the stenosis throat in both a symmetric and asymmetric stenosed geometry. It is also evident that stenosis eccentricity is important, with asymmetry (where the centre of the stenosis does not coincide with the centre of the artery) producing a major change in WSS and flow field. The study of the flow field downstream of a symmetric stenosis exit showed a Kelvin-Helmholtz vortex ring system to occur between the jet exiting the stenosis throat and the low velocity reverse flow region that surrounded it. The strength of these vortices varied between the acceleration and deceleration phase, demonstrating the failings of a quasi-steady assumption. It was shown that varying the external pressure applied to the flow phantom, along with stenosis eccentricity, affected the inlet flow and pressure waveform and the failings of the common assumption to idealise the physiological flow wave with a sinusoidal input was presented.

Multiple-input multiple-output (MIMO) radar has been receiving increasing attention in recent years due to the dramatic advantages offered by MIMO systems in communications. The amount of energy reflected from a common radar target varies considerably with the observation angle, and these scintillations may cause signal fading which severely degrades the performance of conventional radars. MIMO radar with widely spaced antennas is able to view several aspects of a target simultaneously, which realizes a spatial diversity gain to overcome the target scintillation problem, leading to significantly enhanced system performance. Building on the initial studies presented in the literature, MIMO radar is investigated in detail in this thesis. First of all, a finite scatterers model is proposed, based on which the target detection performance of a MIMO radar system with arbitrary array-target configurations is evaluated and analyzed. A MIMO radar involving a realistic target is also set up, whose simulation results corroborate the conclusions drawn based on theoretical target models, validating in a practical setting the improvements in detection performance brought in by the MIMO radar configuration. Next, a hybrid bistatic radar is introduced, which combines the phased-array and MIMO radar configurations to take advantage of both coherent processing gain and spatial diversity gain simultaneously. The target detection performance is first assessed, followed by the evaluation of the direction finding performance, i.e., performance of estimating angle of arrival as well as angel of departure. The presented theoretical expressions can be used to select the best architecture for a radar system, particularly when the total number of antennas is fixed. Finally, a novel two phase radar scheme involving signal retransmission is studied. It is based on the time-reversal (TR) detection and is investigated to improve the detection performance of a wideband MIMO radar or sonar system. Three detectors demanding various amounts of a priori information are developed, whose performance is evaluated and compared. Three schemes are proposed to design the retransmitted waveform with constraints on the transmitted signal power, further enhancing the detection performance with respect to the TR approach.

A series of Total Variation based algorithms are presented for the restoration of bilevel waveforms from observed signals. The proposed model is discussed analytically and numerically via the gradient descent minimization of the TV energy. The application of restoration of bilevel waveforms encoded within barcode images is presented. A super- resolution technique is proposed as a reduction of dimensionality of the image data. The result is a high resolution image from which the encoded bilevel waveform is restored. Implementation of results is shown for synthetic and real images.

Accounting for azimuthal anisotropy is necessary for the processing and inversion of wide-azimuth and wide-aperture seismic data because wave speeds naturally depend on the wave propagation direction. Orthorhombic anisotropy is considered the most effective anisotropic model that approximates the azimuthal anisotropy we observe in seismic data. In the framework of full wave form inversion (FWI), the large number of parameters describing orthorhombic media exerts a considerable trade-off and increases the non-linearity of the inversion problem. Choosing a suitable parameterization for the model, and identifying which parameters in that parameterization could be well resolved, are essential to a successful inversion. In this thesis, I derive the radiation patterns for different acoustic orthorhombic parameterization. Analyzing the angular dependence of the scattering of the parameters of different parameterizations starting with the conventionally used notation, I assess the potential trade-off between the parameters and the resolution in describing the data and inverting for the parameters. In order to build practical inversion strategies, I suggest new parameters (called deviation parameters) for a new parameterization style in orthorhombic media. The novel parameters denoted ∈d, ƞd and δd are dimensionless and represent a measure of deviation between the vertical planes in orthorhombic anisotropy. The main feature of the deviation parameters consists of keeping the scattering of the vertical transversely isotropic (VTI) parameters stationary with azimuth. Using these scattering features, we can condition FWI to invert for the parameters which the data are sensitive to, at different stages, scales, and locations in the model. With this parameterization, the data are mainly sensitive to the scattering of 3 parameters (out of six that describe an acoustic orthorhombic medium): the horizontal velocity in the x1 direction, ∈1 which provides scattering mainly near the zero offset in the x1-x3 vertical plane, and ∈d, which is the ratio of the horizontal velocity squared in the x1 and x2 direction. Since, with this parameterization, the radiation pattern for the horizontal velocity is azimuth independent, we can perform an initial VTI inversion for two parameters (velocity and ∈1), then use ∈d to fit the azimuth variation in the data. This can be done at the reservoir level or any region of the model.

The application of the linear prediction Model for speech waveform analysis to context-independent automatic speaker recognition is explored, primarily in terns of the parametric sensitivity of the model. Feature vectors to characterize speakers are formed from linear prediction speech parameters computed as inverse filter coefficients, reflection coefficients or cepstral coefficients, and also power spectrum parameters via Fast Fourier Transform coefficients. The comparative performance of these parameters is investigated in speaker recognition experiments. The stability of the linear prediction parameters is tested over a range of model order from p=6 to p=30. Two independent speech databases are used to substantiate the experimental results. The quality of the automatic recognition technique is assessed in a novel experiment based on a direct performance comparison with the human skill of aural recognition. Correlation is sought between the performance of the aural and automatic recognition methods, for each of the four parameter sets. Although the recognition accuracy of the automatic system is superior to that of the direct aural technique, the error distributions are highly variable. The performance of the automatic system is shown to be empirically based and unlike the intuitive human process. An extended preamble to the description of the experiments reviews the current art of automatic speaker recognition, with a critical consideration of the performance of linear prediction techniques. As supported by our experimental results, it is concluded that success in the laboratory rests upon a rather fragile foundation. Application to problems beyond the controlled laboratory environment is seen, therefore, to be still more precarious.