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Full-Text Articles in Engineering

Conducting Polymer Nanowires For Multi-Analyte Chemiresistive Sensing, Edward Song Jan 2014

Conducting Polymer Nanowires For Multi-Analyte Chemiresistive Sensing, Edward Song

LSU Doctoral Dissertations

A conducting polymer nanowire-based chemiresistive sensor array was developed for the liquid-phase multi-analyte detection. The ability to distinguish and quantify multiple chemical species with a single sensory device can be useful in many areas including food industry, pollution control, biosensors, and explosives detection. A polyaniline nanowire is a good candidate for use as a chemiresistive sensing material due to its large resistivity change and ease of synthesis. However the two most important issues in chemiresistive sensors are the reproducibility in sensing and the selectivity in chemical species. For improving the reproducibility in polyaniline-based chemiresistive sensing, a self-calibration mechanism was proposed. …


Localization And Security Algorithms For Wireless Sensor Networks And The Usage Of Signals Of Opportunity, Gustavo Andres Chacon Rojas Jan 2014

Localization And Security Algorithms For Wireless Sensor Networks And The Usage Of Signals Of Opportunity, Gustavo Andres Chacon Rojas

LSU Doctoral Dissertations

In this dissertation we consider the problem of localization of wireless devices in environments and applications where GPS (Global Positioning System) is not a viable option. The _x000C_rst part of the dissertation studies a novel positioning system based on narrowband radio frequency (RF) signals of opportunity, and develops near optimum estimation algorithms for localization of a mobile receiver. It is assumed that a reference receiver (RR) with known position is available to aid with the positioning of the mobile receiver (MR). The new positioning system is reminiscent of GPS and involves two similar estimation problems. The _x000C_rst is localization using …


Measurement Of Working, Reflected, And Detrimental Active Power In A Three Phase System, Tracy Toups Jan 2014

Measurement Of Working, Reflected, And Detrimental Active Power In A Three Phase System, Tracy Toups

LSU Doctoral Dissertations

Study of the decomposition of the active power into composite components with respects to power industry economics namely, working active power, reflected active power, and detrimental active power. The working active energy is considered the permanent flow of useful energy to the load that results in deliberate heat, lighting, or torque on the motor shaft. The reflected active energy is the extra component of active energy originating from the load and dissipates on the supply impedance that does not contribute to useful energy. Lastly, detrimental active energy is the flow of harmonic energy from the supply to the load due …


New Approaches To Smart Grid Security With Scada Systems, Bixiang Tang Jan 2014

New Approaches To Smart Grid Security With Scada Systems, Bixiang Tang

LSU Doctoral Dissertations

The use of information technology in electric power grid introduces the vulnerability problem looming the future smart grid. The supervisory control and data acquisition (SCADA)is the first defense, which itself is undermined by potential malicious attacks. This dissertation studies two particular security threats facing the smart grid and SCADA systems: the unobservable attack and the replay attack. The former is well known in fault detection of the power grid and has received renewed interest in the past a few years, while the latter is motivated by the Stuxnet worm allegedly used against the nuclear facilities in Iran. For unobservable attacks, …


Image Enhancement Methods And Applications In Computational Photography, Qinchun Qian Jan 2014

Image Enhancement Methods And Applications In Computational Photography, Qinchun Qian

LSU Doctoral Dissertations

Computational photography is currently a rapidly developing and cutting-edge topic in applied optics, image sensors and image processing fields to go beyond the limitations of traditional photography. The innovations of computational photography allow the photographer not only merely to take an image, but also, more importantly, to perform computations on the captured image data. Good examples of these innovations include high dynamic range imaging, focus stacking, super-resolution, motion deblurring and so on. Although extensive work has been done to explore image enhancement techniques in each subfield of computational photography, attention has seldom been given to study of the image enhancement …


A System Approach To Investing In Uncertain Markets, Iman Khademi Jan 2014

A System Approach To Investing In Uncertain Markets, Iman Khademi

LSU Doctoral Dissertations

We consider the problem of trend-following in US stock market and propose a combined economic and technical model to approach this problem. A bank of linear and nonlinear, discrete-time, low-pass filters with different sampling rates is used to generate timing signals for US stock market indexes such as NASDAQ Composite and S&P 500. These timing signals help us find the appropriate times to step in or out of the market. Back-testing and real-time implementation results along with the risk analysis validate our model. According to the trend of the market, we may adopt a long or short position. If we …


Advanced Statistical Signal Processing Methods In Sensing, Detection, And Estimation For Communication Applications, Hongting Zhang Jan 2014

Advanced Statistical Signal Processing Methods In Sensing, Detection, And Estimation For Communication Applications, Hongting Zhang

LSU Doctoral Dissertations

The applications of wireless communications and digital signal processing have dramatically changed the way we live, work, and learn over decades. The requirement of higher throughput and ubiquitous connectivity for wireless communication systems has become prevalent nowadays. Signal sensing, detection and estimation have been prevalent in signal processing and communications for many years. The relevant studies deal with the processing of information-bearing signals for the purpose of information extraction. Nevertheless, new robust and efficient signal sensing, detection and estimation techniques are still in demand since there emerge more and more practical applications which rely on them. In this dissertation work, …


Advanced Control Of Small-Scale Power Systems With Penetration Of Renewable Energy Sources, Shaghayegh Kazemlou Jan 2014

Advanced Control Of Small-Scale Power Systems With Penetration Of Renewable Energy Sources, Shaghayegh Kazemlou

LSU Doctoral Dissertations

Stability, protection, and operational restrictions are important factors to be taken into account in a proper integration of distributed energy. The objective of this research is presenting advanced controllers for small-scale power systems with penetration of renewable energy sources resources to ensure stable operation after the network disturbances. Power systems with distributed energy resources are modeled and controlled through applying nonlinear control methods to their power electronic interfaces in this research. The stability and control of both ac and dc systems have been studied in a multi-source framework. The dc distribution system is represented as a class of interconnected, nonlinear …


Vocal Fold Analysis From High Speed Videoendoscopic Data, Jing Chen Jan 2014

Vocal Fold Analysis From High Speed Videoendoscopic Data, Jing Chen

LSU Doctoral Dissertations

High speed videoendoscopy (HSV) of the larynx far surpasses the limits of videostroboscopy in evaluating the vocal fold vibratory behavior by providing much higher frame rate. HSV enables the visualization of vocal fold vibratory pattern within an actual glottic cycle. This very detailed infor-mation on vocal fold vibratory characteristics could provide valuable information for the assessment of vocal fold vibratory function in disordered voices and the treatments effects of the behavioral, medical and surgical treatment procedures. In this work, we aim at addressing the problem of classi-fying voice disorders with varying etiology by following four steps described shortly. Our method-ology …


Spectrum Sensing, Spectrum Monitoring, And Security In Cognitive Radios, Erfan Soltanmohammadi Jan 2014

Spectrum Sensing, Spectrum Monitoring, And Security In Cognitive Radios, Erfan Soltanmohammadi

LSU Doctoral Dissertations

Spectrum sensing is a key function of cognitive radios and is used to determine whether a primary user is present in the channel or not. In this dissertation, we formulate and solve the generalized likelihood ratio test (GLRT) for spectrum sensing when both primary user transmitter and the secondary user receiver are equipped with multiple antennas. We do not assume any prior information about the channel statistics or the primary user’s signal structure. Two cases are considered when the secondary user is aware of the energy of the noise and when it is not. The final test statistics derived from …