The way a certain antenna operates is highly dependent on the dielectric medium in which it is placed. Dielectric media can be characterized by their dielectric constant, which is also called relative permittivity. When no electric field is applied, the positive and negative charges of the dielectric molecules are evenly distributed. Application of an electric field disrupts this balance and results in the creation of dipoles. The number of dipoles that are created is proportional to the permittivity of the dielectric. Permittivity is a measure of the sensitivity of the material to an applied electric field. Stated another way, permittivity is a measure of how much energy can be stored in the electric field. This thesis reports the research on several types of on-the-chip antennas such as a rectangular spiral and a rectangular patch. The characteristics of these antennas that are useful to Energy Harvesting are analyzed and the effects of permittivity changes in the dielectrics surrounding the antenna are studied.

With the rapid development of video compression and network technology, real-time video communications has become a popular part of our daily life. Rate control is needed to satisfy the expectation of high quality and to make it possible to transmit over limited bandwidth. The objective of this thesis is to design a rate control scheme for a real-time Transcoding-Compositing Multipoint Video Conferencing System, which operates exclusively in the DCT domain. In this Transcoding-Compositing system, the mode of the composited frame should firstly be decided before encoding the composited image. A mode decision method relying on Karhunen-Loeve scene change detection is proposed. A new linear source Rate-Distortion model is developed in the - domain ( is the percentage of zero), based on which rate control scheme is designed. The designed rate control scheme is parted into three levels: Frame Level, Sub-frame Level, and Macroblock Level. Frame Level rate control decides the bit budget for each frame based on the buffer fullness. Sub-frame Level rate control optimizes the distribution of the bit budget among the decimated sub-images. Based on the linear source model, Macroblock Level rate control carries out an adaptive procedure to precisely control the number of encoding bits for each sub-image.

One of the major challenges for Automatic Speech Recognition is to handle speech variability. Inter-speaker variability is partly due to differences in speakers' anatomy and especially in their Vocal Tract geometry. Dissimilarities in Vocal Tract Length (VTL) are a known source of speech variation. Vocal Tract Length Normalization is a popular Speaker Normalization technique that can be implemented as a transformation of a spectrum frequency axis. We introduce in this document a new spectral transformation for Speaker Normalization. We use the Bilinear Transformation to introduce a new frequency warping resulting from a mapping of a prototype Band-Pass (BP) filter into a general BP filter. This new transformation called the Bandpass Transformation (BPT) offers two degrees of freedom enabling complex warpings of the frequency axis that are different from previous works with the Bilinear Transform. We then define a procedure to use BPT for Speaker Normalization based on the Nelder-Mead algorithm for the estimation of the BPT parameters. We present a detailed study of the performance of our new approach on two test sets with gender dependent and independent systems. Our results demonstrate clear improvements compared to standard methods used in VTL Normalization. A score compensation procedure is presented and results in further improvements of our results by refining our BPT parameter estimation.

Ink jet technologies also known as microdrop technologies are receiving increased interest in applications outside of traditional printing and marking. Because of this, methods and procedures are necessary to evaluate components and fluids of designs for non-printing applications. Much attention has been spent on drop on demand (DOD) printing due to its large commercial availability, which has caused continuous ink jet (CIJ) printing to be neglected. This issue is addressed by developing procedures to photograph droplets produced by a CIJ printer in the absence of charging and deflection. Both an OEM printer and a custom experimental setup are used to supply fluid pressure and modulation voltage to a CIJ modulator and nozzle. The resultant droplets are photographed with two different camera systems, and analyzed with Matlab and ImageJ. With these programs, methods are presented to analyze the velocity, volume, drop production rate, and spacing of the droplets so that these factors can be evaluated in the design of a new system that uses CIJ technology.

A novel sub-optimal low-complexity equalization and turbo-iterative decoding scheme based on running the sum-product algorithm on an aggressively pruned tree is proposed in this paper for use in a multiple transmit and receive antenna (MIMO) system operating over severe frequency-selective fading inter-symbol interference (ISI) channels. The receiver deals with the issue of signal processing complexity which with a full-search equalization grows with power-law. The sum-product algorithm is applied to the pruned tree which is constructed by two main operations, a sphere list detection and a threshold-based tree search algorithms. At a particular node of the tree, only a number of most probable branches in the tree of hypothetical symbols are expanded and included in the list of candidates; at a particular tree-section, all but some of most probable candidates are pruned. This pruned tree takes the soft input and generates the soft output, and is utilized in the turbo-iterative manner with the decoder of the low-density parity check code. We oobtained the approximated error probability using the pair-wise error calculation averaged over the fading ensemble, and use it to bound our simulation results. Our current simulation results are obtained for MIMO systems up to four transmit and four receive antennas, using 4-QAM symbols. They indicate the proposed receiver performs extremely well. The proposed transceiver system is ideal for a system of higher spectral efficiency with even larger signal constellations. Adopting Hassbi-Vikalo's framework, we provide a method which enables a quick evaluation of the signal processing complexity required in the proposed algorithm at a given set of system parameters.

In wave propagation, the phenomenon of dispersion, whereby different frequencies travel at different velocities, can result in significant nonstationarities, i.e., time- and spatially-varying characteristics of the wave. This effect is particularly strong in shallow water sound propagation, due to the waveguide-like action of the ocean bottom and surface. These channel-induced nonstationarities can have a deleterious impact on automatic detection and classification in the absence of signal processing techniques that account for dispersive channel effects. We quantify the effects of dispersion on the spatial and temporal spreading of a propagating wave by considering local temporal, spatial and spectral moments of the modes of the wave. By local moments we mean, for example, the spread (standard deviation) of the wave in time at a particular location; or the average frequency of the wave at a particular time. We implement simple dispersion-based waveguide models of a shallow ocean channel and demonstrate by application to impulsive-source sonar data that simple channel models requiring little environmental information can be used to compensate for the effects of dispersion.

A fundamental theorem of Digital Signal Processing is Shannon's sampling theorem, which dictates the minimum rate (called the Nyquist rate") at which a continuous-time signal must be sampled in order to faithfully reproduce the signal from its samples. If a signal can be reproduced from its samples, then clearly no information about the original signal has been lost in the sampling process. However, when a signal is sampled at a rate lower than the Nyquist Rate, the true spectral content of the original signal is distorted due to aliasing," wherein frequencies in the original signal greater than the sampling frequency appear as lower frequencies in the sampled signal. This distortion is generally held to be irrecoverable, i.e., whenever aliasing occurs, information is considered to be inevitably lost. This research challenges this notion and presents a technique for identifying aliasing and recovering an unaliased version of a signal from its aliased samples. The method is applicable to frequency-modulated (FM) signals with a continuous instantaneous frequency (IF), and utilizes analysis of the IF of the aliased signal to 1) determine whether the signal has potentially been aliased and, if so, 2) compensate for the aliasing by reconstructing an estimate of the true IF of the signal. Time-frequency methods are used to analyze the potentially aliased signal and estimate the IF, together with modulation, re-sampling and interpolation stages to reconstruct an estimate of the unaliased signal. The proposed technique can yield excellent reconstruction of FM signals given ideal estimates of the IF.

This thesis presents an alternative way to test the amount of energy harvested by an antenna. Accurately measuring the amount of energy an antenna harvests is a challenge. The test equipment that touches the antenna can greatly affect the results of the test. Using a VCO to measure an antennas harvested power enables accuracy and prevents the need to attach testing equipment. The VCO is powered by a harvesting antenna. The frequency produced is then output to a transmitting antenna. The output frequency of the VCO can easily be determined and then used to look up the power from the characteristics of the VCO. A background study of types of VCOs, and VCOs available on the market will also be included in this thesis. Finally the experiment setups and results will be presented.

As implantable devices become increasingly sophisticated, a means of communication is required to transmit data to and from the device. A volume conduction antenna model has been developed that meets the size and power constraints of an in vivo environment. This thesis aims to optimize the shape, curvature, and orientation of these antennas. Analytical and numerical analysis shows that the performance is independent of the conic section used to simulate an antenna. Both analyses were also in agreement that highest curvatures achieve maximum surface potentials, and that the angle is dependent on the distance of the antenna from the surface of the head. Analytical analysis suggests that pointing the antenna elements directly at the surface may not be the optimum angle, but rather at a smaller angle. Too few data points were taken to make the same determination from the numerical case but the optimum angle does deviate from the hypothesized angle in the same way, suggesting a similar result. The numerical analysis was important as it facilitated the simulation of the epoxy between the antenna elements. Incorporating epoxy into the simulation showed 30-35% increases in surface potential. A reflective sheet was then added showing further increases in surface potential.

Evoked potentials are defined as potentials that are caused by the electrical activity in the central nervous system after a stimulation .In analysis of evoked potentials the main problem is to extract waveform from the measurements that also contain on-going background electroencephalogram (EEG). The most conventional tool for the analysis of evoked potentials has been the averaging of the measurements over an ensemble of trials. This is the optimal way to improve the signal-to-noise ratio when the evoked potential is a deterministic signal in independent and additive background noise of zero mean. However it is evident that the evoked potential can vary with repetitions of the stimuli. There are two aims of this thesis .The first is to develop a new simulation method for evoked potentials with slow variations among different trials. The second aim is to develop a new method to extract the variations occurring in a number of time-aligned trials. These variations are then added to the mean of the measurements to reconstruct the single trial evoked potentials. The extraction method has been evaluated using both simulated data and real measurements with satisfactory results.