Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 4 of 4

Full-Text Articles in Engineering

Networking And Security Solutions For Vanet Initial Deployment Stage, Baber Aslam Jan 2012

Networking And Security Solutions For Vanet Initial Deployment Stage, Baber Aslam

Electronic Theses and Dissertations

Vehicular ad hoc network (VANET) is a special case of mobile networks, where vehicles equipped with computing/communicating devices (called "smart vehicles") are the mobile wireless nodes. However, the movement pattern of these mobile wireless nodes is no more random, as in case of mobile networks, rather it is restricted to roads and streets. Vehicular networks have hybrid architecture; it is a combination of both infrastructure and infrastructure-less architectures. The direct vehicle to vehicle (V2V) communication is infrastructure-less or ad hoc in nature. Here the vehicles traveling within communication range of each other form an ad hoc network. On the other …


Advanced Design Methodologies And Novel Applications Of Reflectarray Antennas, Payam Nayeri Jan 2012

Advanced Design Methodologies And Novel Applications Of Reflectarray Antennas, Payam Nayeri

Electronic Theses and Dissertations

Reflectarray antennas combine the numerous advantages of printed antenna arrays and reflector antennas and create a hybrid high-gain antenna with a low-profile, low-mass, and diversified radiation performance. Reflectarrays are now emerging as the new generation of high-gain antennas for long-distance communications. In this dissertation, some advanced concepts demonstrating novel features of reflectarray antennas are presented. • First, various approaches for radiation analysis of reflectarray antennas are described and implemented. Numerical results are then presented for a variety of systems and the advantages, limitations, and accuracy of these approaches are discussed and compared with each other. • A broadband technique by …


A Fitness Function Elimination Theory For Blackbox Optimization And Problem Class Learning, Gautham Anil Jan 2012

A Fitness Function Elimination Theory For Blackbox Optimization And Problem Class Learning, Gautham Anil

Electronic Theses and Dissertations

The modern view of optimization is that optimization algorithms are not designed in a vacuum, but can make use of information regarding the broad class of objective functions from which a problem instance is drawn. Using this knowledge, we want to design optimization algorithms that execute quickly (efficiency), solve the objective function with minimal samples (performance), and are applicable over a wide range of problems (abstraction). However, we present a new theory for blackbox optimization from which, we conclude that of these three desired characteristics, only two can be maximized by any algorithm. We put forward an alternate view of …


Optimization Of Process Parameters For Faster Deposition Of Cuin1-Xgaxs2 And Cuin1-Xgaxse2-Ysy Thin Film Solar Cells, Ashwani Kaul Jan 2012

Optimization Of Process Parameters For Faster Deposition Of Cuin1-Xgaxs2 And Cuin1-Xgaxse2-Ysy Thin Film Solar Cells, Ashwani Kaul

Electronic Theses and Dissertations

Thin film solar cells have the potential to be an important contributor to the world energy demand in the 21st century. Among all the thin film technologies, CuInGaSe2 (CIGS) thin film solar cells have achieved the highest efficiency. However, the high price of photovoltaic (PV) modules has been a major factor impeding their growth for terrestrial applications. Reduction in cost of PV modules can be realized by several ways including choosing scalable processes amenable to large area deposition, reduction in the materials consumption of active layers, and attaining faster deposition rates suitable for in-line processing. Selenization-sulfurization of sputtered metallic Cu-In-Ga …