Engineering Commons^™

Surface Modeling And Analysis Using Range Images: Smoothing, Registration, Integration, And Segmentation, Yiyong Sun

Doctoral Dissertations

This dissertation presents a framework for 3D reconstruction and scene analysis, using a set of range images. The motivation for developing this framework came from the needs to reconstruct the surfaces of small mechanical parts in reverse engineering tasks, build a virtual environment of indoor and outdoor scenes, and understand 3D images.

The input of the framework is a set of range images of an object or a scene captured by range scanners. The output is a triangulated surface that can be segmented into meaningful parts. A textured surface can be reconstructed if color images are provided. The framework consists …

Pattern Recognition For Electric Power System Protection, Yong Sheng

Doctoral Dissertations

The objective of this research is to demonstrate pattern recognition tools such as decision trees (DTs) and neural networks that will improve and automate the design of relay protection functions in electric power systems. Protection functions that will benefit from the research include relay algorithms for high voltage transformer protection (TP) and for high impedance fault (HIF) detection. A methodology, which uses DTs and wavelet analysis to distinguish transformer internal faults from other conditions that are easily mistaken for internal faults, has been developed. Also, a DT based solution is proposed to discriminate HIFs from normal operations that may confuse …

High-Temperature, High-Resolution A/D Conversion Using 2nd- And 4th-Order Cascaded Σδ Modulation In 3.3-V 0.5Μm Sos-Cmos, M. Nance Ericson

Doctoral Dissertations

Sigma Delta Modulation is an oversampling technique commonly used in high-resolution analog-to-digital conversion. By employing oversampling and quantization noise shaping, the method allows very high-resolution conversion using low-resolution functional blocks. A multitude of architectural variations of this oversampled class of digitizers has been explored and reported in research literature for a wide variety of applications including seismic imaging, general low-bandwidth high-resolution instrumentation, audio conversion, and most recently high-speed communications.

Data conversion associated with seismic imaging has been recently dominated by this class of converters, though all data acquisition systems require environmental control, preventing placement of the digitizing electronics down-hole. The …

System Impact Of Silicon Carbide Power Electronics On Hybrid Electric Vehicle Applications, Burak Ozpineci

Doctoral Dissertations

The emergence of silicon carbide- (SiC-) based power semiconductor switches with their superior features compared with silicon (Si) based switches has resulted in substantial improvements in the performance of power electronics converter systems. These systems with SiC power devices are more compact, lighter, and more efficient, so they are ideal for high-voltage power electronics applications including hybrid electric vehicle (HEV) power converters.

In this dissertation, first, a power supply converter and a traction drive converter of an HEV are selected and then, the impact of SiC-based power devices on these converters is investigated. Reductions in heatsink size and device losses …