Engineering Commons^™

Empirical Modeling Of Asynchronous Scalp Recorded And Intracranial Eeg Potentials, Komalpreet Kaur

Electrical & Computer Engineering Theses & Dissertations

A Brain-Computer Interface (BCI) is a system that allows people with severe neuromuscular disorders to communicate and control devices using their brain signals. BCIs based on scalp-recorded electroencephalography (s-EEG) have recently been demonstrated to provide a practical, long-term communication channel to severely disabled users. These BCIs use time-domain s-EEG features based on the P300 event-related potential to convey the user's intent. The performance of s-EEG-based BCIs has generally stagnated in recent years, and high day-to-day performance variability exists for some disabled users. Recently intracranial EEG (i-EEG), which is recorded from the cortical surface or the hippocampus, has been successfully used …

Numerical Study Of Poration And Ionic Conduction In Nanopores Caused By High-Intensity, Nanosecond Pulses In Cell, Hao Qiu

Electrical & Computer Engineering Theses & Dissertations

This dissertation focuses on the dynamics and bioeffects of electroporation of biological cell and ionic conduction in nanopores under high-intensity, nanosecond pulses. The electroporation model utilized the current continuity equation and the asymptotic Smoluchowski equation to explore the transmembrane potential and pore density of the plasma and intracellular membranes; the ionic conduction model employed the Poisson-Nernst-Planck equations and the Navier-Stokes equations to analyze the ionic current and ion concentration profile.

Nanosecond electric pulses of high-intensity amplitude can initiate electroporation of intracellular organelles. The pulse parameters and cell electrical properties, that can selectively electroporate liposomes but keep the plasma and nuclear …

Evaluation Of Degradation In Gan High Electron Mobility Transistors Due To The Inverse Piezoelectric Effect, Deepthi Nagulapally

Electrical & Computer Engineering Theses & Dissertations

It has recently been postulated that high voltage stress can result in the degradation of nanoscale structures that are made up of piezoelectric materials. The inverse piezoelectric effect (IPE) is believed to be the likely reason for this degradation mechanism. Basically, the IPE leads to the creation of high internal stresses driven by the presence of an electric field. Consequently, devices based on piezoelectric materials are postulated to undergo defect formation induced by the large mechanical stress arising from the inverse piezoelectric effect in the presence of an applied bias. GaN based devices are mostly observed to show this degradation …

Idpal – A Partially-Adiabatic Energy-Efficient Logic Family: Theory And Applications To Secure Computing, Mihail T. Cutitaru

Electrical & Computer Engineering Theses & Dissertations

Low-power circuits and issues associated with them have gained a significant amount of attention in recent years due to the boom in portable electronic devices. Historically, low-power operation relied heavily on technology scaling and reduced operating voltage, however this trend has been slowing down recently due to the increased power density on chips. This dissertation introduces a new very-low power partially-adiabatic logic family called Input-Decoupled Partially-Adiabatic Logic (IDPAL) with applications in low-power circuits. Experimental results show that IDPAL reduces energy usage by 79% compared to equivalent CMOS implementations and by 25% when compared to the best adiabatic implementation. Experiments ranging …

Characterization Of An Impulse Radiating Antenna In The Near Field, Chandra Barjracharya

Electrical & Computer Engineering Theses & Dissertations

The biological effects of intense sub-nanosecond pulses on tissues or cells are in the dielectric domain and not based on thermal loading as in the conventional microwave radiation, which may lead to an entirely new approach of modifying cell functions. Moreover, the resulting cell functional change may be detected with higher resolution by broadband, sub-nanosecond pulses than conventional narrowband systems. The delivery of intense sub-nanosecond pulses to near-field biological tissues, however, has not been studied, not mentioning the focal depth and volume. In this dissertation, for the first time, an impulse radiating antenna with a balanced feed structure is studied …

Transparent Spectrum Co-Access In Cognitive Radio Networks, Jonathan Daniel Backens

Electrical & Computer Engineering Theses & Dissertations

The licensed wireless spectrum is currently under-utilized by as much as 85%. Cognitive radio networks have been proposed to employ dynamic spectrum access to share this under-utilized spectrum between licensed primary user transmissions and unlicensed secondary user transmissions. Current secondary user opportunistic spectrum access methods, however, remain limited in their ability to provide enough incentive to convince primary users to share the licensed spectrum, and they rely on primary user absence to guarantee secondary user performance. These challenges are addressed by developing a Dynamic Spectrum Co-Access Architecture (DSCA) that allows secondary user transmissions to co-access transparently and concurrently with primary …

Detection Of Ofdm Signals Using Pilot Tones And Applications To Spectrum Sensing For Cognitive Radio Systems, Ahmed Temtam

Electrical & Computer Engineering Theses & Dissertations

Nowadays there are an increasing number of wireless devices which support wireless networking and the need for higher data rate communication is increasing rabidly. As more and more systems go wireless, approaching technologies will face spectral crowding and existence of wireless devices will be an important issue. Because of the limited bandwidth availability, accepting the request for higher capacity and data rates is a challenging task, demanding advanced technologies that can offers new methods of using the available radio spectrum. Cognitive radio introduces a key solution to the spectral increasing issue by presenting the opportunistic usage of spectrum that is …

Ionizing Radiation Detection Using Microstructured Optical Fiber, Stanton Dehaven

Electrical & Computer Engineering Theses & Dissertations

Ionizing radiation detecting microstructured optical fibers are fabricated, modeled and experimentally measured for X-ray detection in the 10-40 keV energy range. These fibers operate by containing a scintillator material which emits visible light when exposed to ionizing radiation. An X-ray source characterized with a CdTe spectrometer is used to quantify the X-ray detection efficiency of the fibers. The solid state CdTe detector is considered 100% efficient in this energy range. A liquid filled microstructured optical fiber (MOF) is presented where numerical analysis and experimental observation leads to a geometric theory of photon transmission using total internal reflection. The model relates …