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Articles 1 - 11 of 11
Full-Text Articles in Physical Sciences and Mathematics
Advanced Iii-V / Si Nano-Scale Transistors And Contacts: Modeling And Analysis, Seung Hyun Park
Advanced Iii-V / Si Nano-Scale Transistors And Contacts: Modeling And Analysis, Seung Hyun Park
Open Access Dissertations
The exponential miniaturization of Si CMOS technology has been a key to the electronics revolution. However, the continuous downscaling of the gate length becomes the biggest challenge to maintain higher speed, lower power, and better electrostatic integrity for each following generation. Hence, novel devices and better channel materials than Si are considered to improve the metal-oxide-semiconductor field-effect transistors (MOSFETs) device performance. III-V compound semiconductors and multi-gate structures are being considered as promising candidates in the next CMOS technology. III-V and Si nano-scale transistors in different architectures are investigated (1) to compare the performance between InGaAs of III-V compound semiconductors and …
Image Analysis Using Visual Saliency With Applications In Hazmat Sign Detection And Recognition, Bin Zhao
Image Analysis Using Visual Saliency With Applications In Hazmat Sign Detection And Recognition, Bin Zhao
Open Access Dissertations
Visual saliency is the perceptual process that makes attractive objects "stand out" from their surroundings in the low-level human visual system. Visual saliency has been modeled as a preprocessing step of the human visual system for selecting the important visual information from a scene. We investigate bottom-up visual saliency using spectral analysis approaches. We present separate and composite model families that generalize existing frequency domain visual saliency models. We propose several frequency domain visual saliency models to generate saliency maps using new spectrum processing methods and an entropy-based saliency map selection approach. A group of saliency map candidates are then …
Tunable Impedance Matching Network Fundamental Limits And Pracitical Considerations, Wesley N. Allen
Tunable Impedance Matching Network Fundamental Limits And Pracitical Considerations, Wesley N. Allen
Open Access Dissertations
As wireless devices continue to increase in utility while decreasing in dimension, design of the RF front-end becomes more complex. It is common for a single handheld device to operate on a plethora of frequency bands, utilize multiple antennae, and be subjected to a variety of environments. One complexity in particular which arises from these factors is that of impedance mismatch. Recently, tunable impedance matching networks have begun to be implemented to address this problem. ^ This dissertation presents the first in-depth study on the frequency tuning range of tunable impedance matching networks. Both the fundamental limitations of ideal networks …
Dynamic Control Of Plasmonic Resonances With Graphene Based Nanostructures, Naresh Kumar Emani
Dynamic Control Of Plasmonic Resonances With Graphene Based Nanostructures, Naresh Kumar Emani
Open Access Dissertations
Light incident on a metallic structure excites collective oscillations of electrons termed as plasmons. These plasmons are useful in control and manipulation of information in nanoscale dimensions and at high operating frequencies. Hence, the field of plasmonics opens up the possibility of developing nanoscale optoelectronic circuitry for computing and sensing applications. One of the challenges in this effort is the lack of tunable plasmonic resonance. Currently, the resonant wavelength of plasmonic structure is fixed by the material and structural parameters. Post-fabrication dynamic control of a plasmonic resonance is rather limited.^ In this thesis we explore the combination of optoelectrical properties …
Dynamic Wireless Power Transfer System For The Unmanned Aerial Vehicles, Tae Sup Lee
Dynamic Wireless Power Transfer System For The Unmanned Aerial Vehicles, Tae Sup Lee
Open Access Theses
UAVs have limitless applications to help our daily lives for the autonomous operations. UAVs have a limited power capacity due to weight constraints and are therefore not able to travel long distances. Ground stations for recharging UAVs throughout different points can increase the flight time of the UAVs with the current UAV battery capacity. This study investigates how the wireless charging system for the ground station can be made more robust when there are misalignments. The wireless charging system is monitored by an Arduino, micro controller, to assess the current condition of charging. The Arduino is able to change the …
Theory Of Topological Insulators And Its Applications, Parijat Sengupta
Theory Of Topological Insulators And Its Applications, Parijat Sengupta
Open Access Dissertations
An important pursuit in semiconductor physics is to discover new materials to sustain the continuous progress and improvements in the current electronic devices. Traditionally, three material types are in use: 1) Metals 2) Semiconductors 3) Insulators. All the three material types are classified according to the energy gap between conduction and valence bands derived from band theory of solids. Recent theoretical predictions and confirmed by experimental observations have provided evidence that there exists materials which behave as insulators in the bulk but possess gapless conducting states on the surface. These new class of materials are called topological insulators (TI). In …
Building Predictive Chemistry Models, Christopher Browne, Nicolas Onofrio, Alejandro Strachan
Building Predictive Chemistry Models, Christopher Browne, Nicolas Onofrio, Alejandro Strachan
The Summer Undergraduate Research Fellowship (SURF) Symposium
Density Functional Theory (DFT) simulations allow for sophisticated modeling of chemical interactions, but the extreme computational cost makes it inviable for large scale applications. Molecular dynamics models, specifically ReaxFF, can model much larger simulations with greater speed, but with lesser accuracy. The accuracy of ReaxFF can be improved by comparing predictions of both methods and tuning ReaxFF’s parameters. Molecular capabilities of ReaxFF were gauged by simulating copper complexes in water over a 200 ps range, and comparing energy predictions against ReaxFF. To gauge solid state capabilities, volumetric strain was applied to simulated copper bulk and the strain response functions used …
Improved Microrobotic Control Through Image Processing And Automated Hardware Interfacing, Archit R. Aggarwal, Wuming Jing, David J. Cappelleri
Improved Microrobotic Control Through Image Processing And Automated Hardware Interfacing, Archit R. Aggarwal, Wuming Jing, David J. Cappelleri
The Summer Undergraduate Research Fellowship (SURF) Symposium
Untethered submilliliter-sized robots (microrobots) are showing potential use in different industrial, manufacturing and medical applications. A particular type of these microrobots, magnetic robots, have shown improved performance in power and control capabilities compared to the other thermal and electrostatic based robots. However, the magnetic robot designs have not been assessed in a robust manner to understand the degree of control in different environments and their application feasibility. This research project seeks to develop a custom control software interface to provide a holistic tool for researchers to evaluate the microrobotic performance through advance control features. The software deliverable involved two main …
Tracking Dynamic Construction Objects ---A Key Node Modeling Approach Using Color-Depth Cameras, Chenxi Yuan
Tracking Dynamic Construction Objects ---A Key Node Modeling Approach Using Color-Depth Cameras, Chenxi Yuan
Open Access Theses
A construction site presents a dynamic scenario. Locations of multiple objects are continuously changing and a lot of objects enter and exit the site in high frequencies. Meanwhile a construction activity consists of a large amount of stochastic operations, many uncertainties occur when making decisions. Believing that detecting, locating and tracking dynamic construction objects in real time improve construction productivity and enhance construction safety, a large number of studies have applied a variety of sensing technologies to construction sites. Hybrid image-point cloud sensing technologies, such as color-depth cameras, have a great potential in achieving real time object recognition and tracking …
Energy Efficient Hybrid Computing Systems Using Spin Devices, Mrigank Sharad
Energy Efficient Hybrid Computing Systems Using Spin Devices, Mrigank Sharad
Open Access Dissertations
Emerging spin-devices like magnetic tunnel junctions (MTJ's), spin-valves and domain wall magnets (DWM) have opened new avenues for spin-based logic design. This work explored potential computing applications which can exploit such devices for higher energy-efficiency and performance. The proposed applications involve hybrid design schemes, where charge-based devices supplement the spin-devices, to gain large benefits at the system level. As an example, lateral spin valves (LSV) involve switching of nanomagnets using spin-polarized current injection through a metallic channel such as Cu. Such spin-torque based devices possess several interesting properties that can be exploited for ultra-low power computation. Analog characteristic of spin …
Optical Position Sensing In Free Space Optical Communication, Muhammad Salman Bashir
Optical Position Sensing In Free Space Optical Communication, Muhammad Salman Bashir
Open Access Theses
In this thesis the performance of three estimators, (center of gravity, template matching and maximum likelihood (MLE)) to estimate the center of the beam on a photoemissive receiver array in a Free Space Optics (FSO) system, is compared in terms of mean square error. Simulations have been conducted in Matlab by generating a two dimensional nonhomogeneous Poisson process, and, mean square error is computed for three estimators. The cases of continuous and discrete arrays are also considered for various levels of signal-to-noise (SNR) ratio. Simulations have shown that the MLE gives the least mean squared error and especially performs significantly …