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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Investigation of Indoor Propagation Algorithms for Localization Purposes: Simulation and Measurements of Indoor Propagation Algorithms for Localization Applications using Wall Correction Factors, Local Mean Power Estimation and Ray Tracing Validations

Obeidat, Huthaifa A.N. January 2018 (has links)
The objective of this work is to enhance the awareness of the indoor propagation behaviour, by a set of investigations including simulations and measurements. These investigations include indoor propagation behaviour, local mean power estimation, proposing new indoor path loss model and introducing a case study on 60 GHz propagation in indoor environments using ray tracing and measurements. A summary of propagation mechanisms and manifestations in the indoor environment is presented. This comprises the indoor localization techniques using channel parameters in terms of angle of arrival (AOA), time of arrival (TOA) and received signal strength (RSS). Different models of path loss, shadowing and fast fading mechanisms are explored. The concept of MIMO channels is studied using many types of deterministic channel modelling such as Finite Difference Time Domain, Ray tracing and Dominant path model. A comprehensive study on estimating local average of the received signal strength (RSS) for indoor multipath propagation is conducted. The effect of the required number of the RSS data and their Euclidian distances between the neighbours samples are investigated over 1D, 2D and 3D configurations. It was found that the effect of fast fading was reduced sufficiently using 2D horizontal’s arrangement with larger spacing configuration. A modified indoor path loss prediction model is presented namely effective wall loss model (EWLM). The modified model with wall correction factors is compared to other indoor path loss prediction models using simulation data (for 2.4, 5, 28, 60 and 73.5 GHz) and real-time measurements (for 2.4 and 5 GHz). Different operating frequencies and antenna polarizations are considered to verify the observations. In the simulation part, EWLM shows the best performance among other models. Similar observations were recorded from the experimental results. Finally, a detailed study on indoor propagation environment at 60 GHz is conducted. The study is supported by Line of Sight (LoS) and Non-LoS measurements data. The results were compared to the simulated ones using Wireless-InSite ray tracing software. Several experiments have confirmed the reliability of the modelling process based on adjusted material properties values from measurements.
52

Diverse Polarization Extension to MUSIC Applied to a Circular Array of H-Plane Horns

Whelan, Jedidiah J. January 2010 (has links)
No description available.
53

Implementation of Geometrically Based Single-Bounce Models for Simulation of Angle-of-Arrival of Multipath Delay Components in the Wireless Channel Simulation Tools, SMRCIM and SIRCIM

Nuckols, John Eric 11 August 1999 (has links)
As the demand for wireless communication systems has exploded over the past few years, many researchers have taken on the challenge to model wireless channels more accurately. These models are very useful for enhancing the design of all aspects of wireless communications. Smart antennas and systems used in position location are among the most popular new studies that require signal information such as the amplitude, phase, and angle-of-arrival (AOA) of multipath delay spreads. For proper and efficient implementation of future systems, emerging wireless systems must be able to exploit processing of spatial information. The goal of the work presented in this thesis is to further improve two channel modeling tools, SMRCIM and SIRCIM, by implementing new geometrical models that provide users with angle-of-arrival information as well as amplitude and phase data for wideband wireless communication channels. The new angle-of-arrival models are explained and pseudo code is provided to demonstrate the software implementation of the models. Likewise, the channel models are explained and the usage and results of the simulation tools are described. The SMRCIM and SIRCIM tools are currently being used by researchers throughout the world. <i>[Vita removed March 5, 2012. Gmc]</i> / Master of Science
54

Brave New World Reloaded: Advocating for Basic Constitutional Search Protections to Apply to Cell Phones from Eavesdropping and Tracking by Government and Corporate Entities

Berrios-Ayala, Mark 01 December 2013 (has links)
Imagine a world where someone’s personal information is constantly compromised, where federal government entities AKA Big Brother always knows what anyone is Googling, who an individual is texting, and their emoticons on Twitter. Government entities have been doing this for years; they never cared if they were breaking the law or their moral compass of human dignity. Every day the Federal government blatantly siphons data with programs from the original ECHELON to the new series like PRISM and Xkeyscore so they can keep their tabs on issues that are none of their business; namely, the personal lives of millions. Our allies are taking note; some are learning our bad habits, from Government Communications Headquarters’ (GCHQ) mass shadowing sharing plan to America’s Russian inspiration, SORM. Some countries are following the United States’ poster child pose of a Brave New World like order of global events. Others like Germany are showing their resolve in their disdain for the rise of tyranny. Soon, these new found surveillance troubles will test the resolve of the American Constitution and its nation’s strong love and tradition of liberty. Courts are currently at work to resolve how current concepts of liberty and privacy apply to the current conditions facing the privacy of society. It remains to be determined how liberty will be affected as well; liberty for the United States of America, for the European Union, the Russian Federation and for the people of the World in regards to the extent of privacy in today’s blurred privacy expectations.

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