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Full-Text Articles in Engineering
Wideband Satcom Model: Evaluation Of Numerical Accuracy And Efficiency, Andrew J. Knisely, Andrew Terzuoli
Wideband Satcom Model: Evaluation Of Numerical Accuracy And Efficiency, Andrew J. Knisely, Andrew Terzuoli
Faculty Publications
The spectral method is typically applied as a simple and efficient method to solve the parabolic wave equation in phase screen scintillation models. The critical factors that can greatly affect the spectral method accuracy is the uniformity and smoothness of the input function. This paper observes these effects on the accuracy of the finite difference and the spectral methods applied to a wideband SATCOM signal propagation model simulated in the ultra-high frequency (UHF) band. The finite difference method uses local pointwise approximations to calculate a derivative. The spectral method uses global trigonometric interpolants that achieve remarkable accuracy for continuously differentiable …
Cyber-Physical Security With Rf Fingerprint Classification Through Distance Measure Extensions Of Generalized Relevance Learning Vector Quantization, Trevor J. Bihl, Todd J. Paciencia, Kenneth W. Bauer Jr., Michael A. Temple
Cyber-Physical Security With Rf Fingerprint Classification Through Distance Measure Extensions Of Generalized Relevance Learning Vector Quantization, Trevor J. Bihl, Todd J. Paciencia, Kenneth W. Bauer Jr., Michael A. Temple
Faculty Publications
Radio frequency (RF) fingerprinting extracts fingerprint features from RF signals to protect against masquerade attacks by enabling reliable authentication of communication devices at the “serial number” level. Facilitating the reliable authentication of communication devices are machine learning (ML) algorithms which find meaningful statistical differences between measured data. The Generalized Relevance Learning Vector Quantization-Improved (GRLVQI) classifier is one ML algorithm which has shown efficacy for RF fingerprinting device discrimination. GRLVQI extends the Learning Vector Quantization (LVQ) family of “winner take all” classifiers that develop prototype vectors (PVs) which represent data. In LVQ algorithms, distances are computed between exemplars and PVs, and …
Evaluating Smartphones For Infrastructure Work Order Management, Victor L. Guinn, Brent T. Langhals, John J. Elshaw
Evaluating Smartphones For Infrastructure Work Order Management, Victor L. Guinn, Brent T. Langhals, John J. Elshaw
Faculty Publications
Infrastructure managers require timely and accurate state information to diagnose, prioritize, and repair the substantial infrastructure assets supporting modern society. Challenges in obtaining sufficient information can often be attributed to inadequate data collection procedures (phone calls, paper reports, etc.) or a general lack of knowledge or ability on the part of the reporting individual to accurately convey what is actually wrong with the facility. Fortunately, modern smart-phone technology offers the potential to improve maintenance work requests by providing better geolocation and problem description accuracy. An experiment simulating real-world maintenance requests was conducted comparing smart-phones with traditional verbal work order request …
Length Selectable, Hardware Efficient Pseudorandom Code Generator, John F. Brendle Jr., James P. Stephens Sr., Michael A. Temple, Robert S. Parks
Length Selectable, Hardware Efficient Pseudorandom Code Generator, John F. Brendle Jr., James P. Stephens Sr., Michael A. Temple, Robert S. Parks
AFIT Patents
A method and device for generating a pseudorandom electrical signal for enabling spread spectrum communication scrambling by directing data entry into pseudorandom number generator integrated circuit chip controlling registers using a length selectable feedback logic data sequence and either computer programmable selector means or manual selector means to communicate the logic data sequence characters to buffers. The logic data sequence characters are clocked to a pseudorandom number generating register of an integrated circuit chip and the pseudorandom electrical signal is generated by selectively tapping a signal code therefrom. The method and device features a pseudorandom electrical signal length varying capability …
Apparatus And Method For Two Stage Hybrid Space-Time Adaptive Processing In Radar And Communication Systems, Todd B. Hale, Michael C. Wicks, Raviraj S. Adve
Apparatus And Method For Two Stage Hybrid Space-Time Adaptive Processing In Radar And Communication Systems, Todd B. Hale, Michael C. Wicks, Raviraj S. Adve
AFIT Patents
A Two-Stage Hybrid algorithm offers significant improvement in the false alarm rate and detection performance of Space-Time Adaptive Processing in non-homogeneous environments for both radar and digital communications. The first stage analyzes data from a range cell of interest by direct data domain processing, suppressing discrete interferers within the range cell of interest. The second stage implements a purely statistical STAP algorithm, preferably an enhanced version of the Joint-Domain Localized ("JDL") statistical algorithm. For radar this second stage estimates the interference within the range cell of interest from the surrounding range cells. For a communications system, the second stage estimates …
Optically Phased Laser Transmitter, Janet S. Fender, Salvatore J. Cusumano, Robert R. Butts, Christopher R. Dehainaut
Optically Phased Laser Transmitter, Janet S. Fender, Salvatore J. Cusumano, Robert R. Butts, Christopher R. Dehainaut
AFIT Patents
An apparatus and technique are described for phasing the outputs of a multiplier telescope array used as a laser transmitter. The technique uses samples of the transmitted beams to control optical path lengths through the separate telescopes so that the beams add coherently at the receiver. The phasing concept is applicable both to systems which provide inputs to the multiple telescopes by dividing a single laser beam and to systems in which the inputs to the telescopes and multiple, phase-locked laser beams. The approach is also compatible with single line and multi-line lasers, and it does not entail stringent alignment …