Signal Processing Commons^™

Impact Of Primary User Activity On The Performance Of Energy-Based Spectrum Sensing In Cognitive Radio Systems, Sara L. Macdonald

Electrical & Computer Engineering Theses & Dissertations

Increasing numbers of wireless devices and mobile data requirements have led to a spectrum shortage. However spectrum utilization percentages are often low due to the current static spectrum allocation process where primary users (PUs) are given exclusive use to spectrum. Several mechanisms to increase spectrum utilization have been proposed including opportunistic spectrum access (OSA). Cognitive Radio (CR) is an emerging concept in wireless communication systems that aims to enable OSA in licensed frequencies by secondary users (SUs). CR systems are expected to sense the spectrum in order to determine if the PU is transmitting. Therefore OSA performance relies on the …

The Miniaturization Of The Afit Random Noise Radar, Aaron T. Myers

Theses and Dissertations

Advances in technology and signal processing techniques have opened the door to using an UWB random noise waveform for radar imaging. This unique, low probability of intercept waveform has piqued the interest of the U.S. DoD as well as law enforcement and intelligence agencies alike. While AFIT's noise radar has made significant progress, the current architecture needs to be redesigned to meet the space constraints and power limitations of an aerial platform. This research effort is AFIT's first attempt at RNR miniaturization and centers on two primary objectives: 1) identifying a signal processor that is compact, energy efficient, and capable …

Automatic Modulation Classification Of Common Communication And Pulse Compression Radar Waveforms Using Cyclic Features, John A . Hadjis

Theses and Dissertations

This research develops a feature-based MAP classification system and applies it to classify several common pulse compression radar and communication modulations. All signal parameters are treated as unknown to the classifier system except SNR and the signal carrier frequency. The features are derived from estimated duty cycle, cyclic spectral correlation, and cyclic cumulants. The modulations considered in this research are BPSK, QPSK, 16-QAM, 64-QAM, 8-PSK, and 16-PSK communication modulations, as well as Barker coded, Barker coded, Barker coded, Frank coded, Px49 coded, and LFM pulse compression modulations. Simulations show that average correct signal modulation type classification %C 90% is achieved …

3d Digital Image Processing For Biofilm Quantification From Confocal Laser Scanning Microscopy, Jerzy S. Zielinski

Theses and Dissertations

The dramatic increase in number and volume of digital images produced in medical diagnostics, and the escalating demand for rapid access to these relevant medical data, along with the need for interpretation and retrieval has become of paramount importance to a modern healthcare system. Therefore, there is an ever growing need for processed, interpreted and saved images of various types. Due to the high cost and unreliability of human-dependent image analysis, it is necessary to develop an automated method for feature extraction, using sophisticated mathematical algorithms and reasoning. This work is focused on digital image signal processing of biological and …

Detection Optimization Of The Progressive Multi-Channel Correlation Algorithm Used In Infrasound Nuclear Treaty Monitoring, Anthony M. Runco

Theses and Dissertations

This thesis develops methods to determine optimum detection thresholds for the Progressive Multi-Channel Correlation (PMCC) algorithm used by the International Data Centre (IDC) to perform infrasound station-level nuclear-event detection. Receiver Operating Characteristic (ROC) curve analysis is used with real ground truth data to determine the trade-off between the probability of detection (P sub D) and the false alarm rate (FAR) at various consistency detection thresholds. Further, statistical detection theory via maximum a posteriori and Bayes cost approaches is used to determine station-level optimum family size thresholds of grouped detection pixels with similar signal attributes (i.e. trace velocity, azimuth, time of …

Discrimination Between Child And Adult Forms Using Radar Frequency Signature Analysis, Stephanie R. Keith

Theses and Dissertations

In this thesis we develop a method to discriminate between adult and child radar signatures. In particular, we examine radar data measured from behind a wall, which introduces radar signal attenuation and multipath effects. To investigate the child/adult discrimination problem in a through-wall, multipath scenario, a previously developed free-space human scattering model was expanded to incorporate multiple paths, and the effects of transmission through, and reflections from, walls and ground. The ground was modeled as a perfectly reflecting surface, while the walls were modeled as homogeneous concrete slabs. Twenty-five reflection paths were identified, involving the direct paths, as well as …

Development And Characterization Of A Chromotomosynthetic Hyperspectral Imaging System, Randall L. Bostick

Theses and Dissertations

A chromotomosynthetic imaging (CTI) methodology based upon mathematical reconstruction of a set of 2-D spectral projections to collect high-speed (100 Hz) 3-D hyperspectral data cube has been proposed. The CTI system can simultaneously provide usable 3-D spatial and spectral information, provide high-frame rate slitless 1-D spectra, and generate 2-D imagery equivalent to that collected with no prism in the optical system. The wavelength region where prism dispersion is highest (500 nm) is most sensitive to loss of spectral resolution in the presence of systematic error, while wavelengths 600 nm suffer mostly from a shift of the spectral peaks. The quality …

2013 Acuta/Nacubo State Of Resent Report

ACUTA: Other Publications

In This Issue

Introduction

Methodology

Executive Summary

Findings

Coverage & Bandwidth Demands

ResNet Management & Support

ResNet Costs & Funding

Alternative Models

Advanced Water Vapor Lidar Detection System, Hani Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

In the present water vapor lidar system, the detected signal is sent over long cables to a waveform digitizer in a CAMAC crate. This has the disadvantage of transmitting analog signals for a relatively long distance, which is subjected to pickup noise, leading to a decrease in the signal to noise ratio.

Generally, errors in the measurement of water vapor with the DIAL method arise from both random and systematic sources. Systematic errors in DIAL measurements are caused by both atmospheric and instrumentation effects. The selection of the on-line alexandrite laser with a narrow linewidth, suitable intensity and high spectral …

Independent Component Analysis Enhancements For Source Separation In Immersive Audio Environments, Yue Zhao

Theses and Dissertations--Electrical and Computer Engineering

In immersive audio environments with distributed microphones, Independent Component Analysis (ICA) can be applied to uncover signals from a mixture of other signals and noise, such as in a cocktail party recording. ICA algorithms have been developed for instantaneous source mixtures and convolutional source mixtures. While ICA for instantaneous mixtures works when no delays exist between the signals in each mixture, distributed microphone recordings typically result various delays of the signals over the recorded channels. The convolutive ICA algorithm should account for delays; however, it requires many parameters to be set and often has stability issues. This thesis introduces the …

Multi-Mode Self-Referencing Surface Plasmon Resonance Sensors, Jing Guo

Theses and Dissertations--Electrical and Computer Engineering

Surface-plasmon-resonance (SPR) sensors are widely used in biological, chemical, medical, and environmental sensing. This dissertation describes the design and development of dual-mode, self-referencing SPR sensors supporting two surface-plasmon modes (long- and short-range) which can differentiate surface binding interactions from bulk index changes at a single sensing location. Dual-mode SPR sensors have been optimized for surface limit of detection (LOD). In a wavelength interrogated optical setup, both surface plasmons are simultaneously excited at the same location and incident angle but at different wavelengths. To improve the sensor performance, a new approach to dual-mode SPR sensing is presented that offers improved differentiation …

Target Tracking With Binary Sensor Networks, Mengmei Liu

Theses and Dissertations--Electrical and Computer Engineering

Binary Sensor Networks are widely used in target tracking and target parameter estimation. It is more computationally and financially efficient than surveillance camera systems. According to the sensing area, binary sensors are divided into disk shaped sensors and line segmented sensors. Different mathematical methods of target trajectory estimation and characterization are applied. In this thesis, we present a mathematical model of target tracking including parameter estimation (size, intrusion velocity, trajectory, etc.) with line segmented sensor networks. Software simulation and hardware experiments are built based on the model. And we further analyze how the quantization noise affects the results.

Microphone Array Optimization In Immersive Environments, Jingjing Yu

Theses and Dissertations--Electrical and Computer Engineering

The complex relationship between array gain patterns and microphone distributions limits the application of traditional optimization algorithms on irregular arrays, which show enhanced beamforming performance for human speech capture in immersive environments. This work analyzes the relationship between irregular microphone geometries and spatial filtering performance with statistical methods. Novel geometry descriptors are developed to capture the properties of irregular microphone distributions showing their impact on array performance. General guidelines and optimization methods for regular and irregular array design are proposed in immersive (near-field) environments to obtain superior beamforming ability for speech applications. Optimization times are greatly reduced through the objective …

An Attitude Determination System With Mems Gyroscope Drift Compensation For Small Satellites, Maxwell Bezold

Theses and Dissertations--Electrical and Computer Engineering

This thesis presents the design of an attitude determination system for small satellites that automatically corrects for attitude drift. Existing attitude determination systems suffer from attitude drift due to the integration of noisy rate gyro sensors used to measure the change in attitude. This attitude drift leads to a gradual loss in attitude knowledge, as error between the estimated attitude and the actual attitude increases.

In this thesis a Kalman filter is used to complete sensor fusion which combines sensor observations with a projected attitude based on the dynamics of the satellite. The system proposed in this thesis also utilizes …

Visual Attitude Propagation For Small Satellites, Samir Ahmed Rawashdeh

Theses and Dissertations--Electrical and Computer Engineering

As electronics become smaller and more capable, it has become possible to conduct meaningful and sophisticated satellite missions in a small form factor. However, the capability of small satellites and the range of possible applications are limited by the capabilities of several technologies, including attitude determination and control systems. This dissertation evaluates the use of image-based visual attitude propagation as a compliment or alternative to other attitude determination technologies that are suitable for miniature satellites. The concept lies in using miniature cameras to track image features across frames and extracting the underlying rotation.

The problem of visual attitude propagation as …

Perceptual Ruler For Quantifying Speech Intelligibility In Cocktail Party Scenarios, Kirstin M. Brangers

Theses and Dissertations--Electrical and Computer Engineering

Systems designed to enhance intelligibility of speech in noise are difficult to evaluate quantitatively because intelligibility is subjective and often requires feedback from large populations for consistent evaluations. Attempts to quantify the evaluation have included related measures such as the Speech Intelligibility Index. These require separating speech and noise signals, which precludes its use on experimental recordings. This thesis develops a procedure using an Intelligibility Ruler (IR) for efficiently quantifying intelligibility. A calibrated Mean Opinion Score (MOS) method is also implemented in order to compare repeatability over a population of 24 subjective listeners. Results showed that subjects using the IR …

Tunable Fano Resonances Based On Two-Beam Interference In Microring Resonator, Ting Hu, Ping Yu, Chen Qui, Huiye Qui, Fan Wang, Mei Yang, Xiaoqing Jiang, Hui Yu, Jianyi Yang

Electrical & Computer Engineering Faculty Research

In this paper, a resonant system is demonstrated on silicon-on-insulator wafer to achieve tunable Fano resonances. In this system, the Fano resonance originates from the interference of two beams resonant in the microring resonator. The shapes of the Fano resonances are tunable through controlling the phase difference of the two beams. Both large slope and high extinctionratio (ER) are obtained when the phase difference is 0.5π or 1.5π. Experimental results show that Fano resonances with steep slope and ER over 20 dB are achieved in the whole free spectral range by controlling the microheaters to meet the phase condition.

Estimation Of Performance Indices For The Planning Of Sustainable Transportation Systems, Alexander Paz, Pankaj Maheshwari

Electrical & Computer Engineering Faculty Research

In the context of sustainable transportation systems, previous studies have either focused only on the transportation systemor have not used a methodology that enables the treatment of incomplete, vague, and qualitative information associated with the available data. This study proposes a system of systems (SOS) and a fuzzy logic modeling approach. The SOS includes the Transportation, Activity, and Environment systems. The fuzzy logic modeling approach enables the treatment of the vagueness associated with some of the relevant data. Performance Indices (PIs) are computed for each system using a number of performance measures. The PIs illustrate the aggregated performance of each …

Framework For Simulation Of Heterogeneous Mpsoc For Design Space Exploration, Bisrat Tafesse, Venkatesan Muthukumar

Electrical & Computer Engineering Faculty Research

Due to the ever-growing requirements in high performance data computation, multiprocessor systems have been proposed to solve the bottlenecks in uniprocessor systems. Developing efficient multiprocessor systems requires effective exploration of design choices like application scheduling, mapping, and architecture design. Also, fault tolerance in multiprocessors needs to be addressed. With the advent of nanometer-process technology for chip manufacturing, realization of multiprocessors on SoC (MpSoC) is an active field of research. Developing efficient low power, fault-tolerant task scheduling, and mapping techniques for MpSoCs require optimized algorithms that consider the various scenarios inherent in multiprocessor environments. Therefore there exists a need to develop …

Automated Extraction And Classification Of Time-Frequency Contours In Humpback Vocalizations, Hui Ou, Whitlow W.L. Au, Lisa M. Zurk, Marc O. Lammers

Electrical and Computer Engineering Faculty Publications and Presentations

A time-frequency contour extraction and classification algorithm was created to analyze humpback whale vocalizations. The algorithm automatically extracted contours of whale vocalization units by searching for gray-level discontinuities in the spectrogram images. The unit-to-unit similarity was quantified by cross-correlating the contour lines. A library of distinctive humpback units was then generated by applying an unsupervised, cluster-based learning algorithm. The purpose of this study was to provide a fast and automated feature selection tool to describe the vocal signatures of animal groups. This approach could benefit a variety of applications such as species description, identification, and evolution of song structures. The …