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Full-Text Articles in Engineering
Wireless Localization In The Absence Of Gps, Hyundeok Kang
Wireless Localization In The Absence Of Gps, Hyundeok Kang
LSU Master's Theses
In this thesis, wireless localization is investigated based on multiple noisy estimates of the time-difference of arrival (TDOA) at each pair of the n >= 4 sensors with different but known locations using WiFi opportunistic signals. Our work is comprehensive and includes channel estimation, symbol detection, TDOA estimation, and location estimation. To mitigate the multipath issue induced by wideband signals, such as WiFi, frequency-division is employed to decompose the wideband RF signal into multiple non-overlapping narrowband signals. To minimize the adverse effects of the clock drift, time-division is proposed to divide the signal into multiple non-overlapping signals in the time …
Localization And Security Algorithms For Wireless Sensor Networks And The Usage Of Signals Of Opportunity, Gustavo Andres Chacon Rojas
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 …
A Nonlocal Model For Coupled Damage-Plasticity Incorporating Gradients Of Internal State Variables At Multiscales, Robert J. Dorgan
A Nonlocal Model For Coupled Damage-Plasticity Incorporating Gradients Of Internal State Variables At Multiscales, Robert J. Dorgan
LSU Doctoral Dissertations
The thermodynamically consistent formulation and the subsequent numerical implementation of a gradient enhanced continuum coupled damage-plasticity model as a constitutive framework to model ill-posed localization problems is presented. By the introduction of "nonlocal," gradient-enhanced measures in the plasticity potential function and yield criterion and in the damage potential function and damage criterion, the proposed model introduces microstructural characteristic material length scales which allows the size of localized zones to be predicted based on material constants, as opposed to local models where the loss of ellipticity causes the localized zones to be mesh dependent.
The gradient model proposed introduces non-linear functions …