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Articles 331 - 360 of 473

Full-Text Articles in Electrical and Computer Engineering

People Matching For Transportation Planning Using Optimized Features And Texel Camera Data For Sequential Estimation, Ziang Wang May 2012

People Matching For Transportation Planning Using Optimized Features And Texel Camera Data For Sequential Estimation, Ziang Wang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis explores pattern recognition in the dynamic setting of public transportation, such as a bus, as people enter and later exit from a doorway. Matching the entrance and exit of each individual provides accurate information about individual riders such as how long a person is on a bus and which stops the person uses. At a higher level, matching exits to entries provides information about the distribution of traffic flow across the whole transportation system. A texel camera is implemented and multiple measures of people are made where the depth and color data are generated. A large number of …


Carrier Frequency Offset Estimation For Orthogonal Frequency Division Multiplexing, Nagaravind Challakere May 2012

Carrier Frequency Offset Estimation For Orthogonal Frequency Division Multiplexing, Nagaravind Challakere

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The objective of the research for this thesis is to improve the performance of the Orthogonal Frequency Division Multiplexing (OFDM) system by minimising the impact of frequency offset at the receive end. OFDM is a popular standard used in wireless communication systems such as cellphone networks and broadband internet. In an OFDM system, the data symbols modulate the carrier signal at the transmitter. Usually, the receiver function generator performs the demodulation task. In the absence of frequency offset compensation, the transmitted symbols can not be effectively recovered upon reception. This leads to packet loss and a degradation of the Quality …


An Milp-Based Aging-Aware Routing Algorithm For Nocs, Kshitij Bhardwaj, Koushik Chakraborty, Sanghamitra Roy Mar 2012

An Milp-Based Aging-Aware Routing Algorithm For Nocs, Kshitij Bhardwaj, Koushik Chakraborty, Sanghamitra Roy

Electrical and Computer Engineering Faculty Publications

Network-on-Chip (NoC) architectures have emerged as a better replacement of the traditional bus-based communication in the many-core era. However, continuous technology scaling has made aging mechanisms such as Negative Bias Temperature Instability (NBTI) and electromigration primary concerns in NoC design. In this paper1, we propose a novel system-level aging model to model the effects of asymmetric aging in NoCs. We observe a critical need of a holistic aging analysis, which when combined with power-performance optimization, poses a multi-objective design challenge. To solve this problem, we propose a Mixed Integer Linear Programming (MILP)-based aging-aware routing algorithm that optimizes the various design …


Stack Aware Threshold Voltage Assignment In 3-D Multicore Designs, Koushik Chakraborty, Sanghamitra Roy Mar 2012

Stack Aware Threshold Voltage Assignment In 3-D Multicore Designs, Koushik Chakraborty, Sanghamitra Roy

Electrical and Computer Engineering Faculty Publications

Due to the inherent nature of heat flow in 3-D integrated circuits, stacked dies exhibit a wide range of thermal characteristics. The temperature of dies progressively increases with increasing distance from the heat sink. This heterogeneous temperature profile coupled with the strong dependence of leakage on temperature and process variation plays havoc in achieving system level energy efficiency in such systems, complicating the task of power provisioning in 3-D multicores. In this paper, we address this power provisioning challenge in 3-D ICs by advocating a novel stack aware microprocessor design paradigm, where the circuit designers are aware of the intended …


Closed-Loop Attitude Control Using Fluid Dynamic Vectoring On An Aerospike Nozzle, Nathan Erni Dec 2011

Closed-Loop Attitude Control Using Fluid Dynamic Vectoring On An Aerospike Nozzle, Nathan Erni

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Attitude control of a prototype satellite bus using fluid mechanical vectoring on an aerospike nozzle is demonstrated. The design achieves thrust vectoring by injecting propellant asymmetrically into the unconstrained aerospike exhaust plume near the nozzle base. The prototype system uses cold-gas thrusters to both spin-up and de-tumble the test article. The system is configured with axially directed annular flows that produce large longitudinal thrusts and smaller secondary lateral-injection flows for side thrusts. Both open and closed-loop attitude control, with and without main aerospike annular flow active, are demonstrated. Proportional, integral, derivative (PID) regulation is used for closed-loop attitude control. When …


A Model For Rapid Charging Events On International Space Station, Debrup Hui Dec 2011

A Model For Rapid Charging Events On International Space Station, Debrup Hui

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Surface charging by plasma can be a serious issue for any spacecraft. Though significant charging is not observed in all spacecrafts at all times, it only requires a single episode of extreme charging to result in serious damage. The International Space Station (ISS) is an interesting platform to study these charging effects because of its size and relatively high voltage systems. Of the many kinds of charging observed on ISS, the rapid charging events during solar eclipse exit in a low-density ionosphere is not yet understood. This report is an investigation to understand this phenomenon. This report proposes a simple …


Distributed Electrical Power System In Cubesat Applications, Robert Burt Dec 2011

Distributed Electrical Power System In Cubesat Applications, Robert Burt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The cubesat spacecraft was conceived over ten years ago. Since that time, close to 100 cubesat satellites have either been launched or are in the process of construction. Although started as an educational teaching tool, the cubesat is gaining popularity in the satellite industry and is making inroads as a standard architecture for many nano and pico satellite applications. The electrical power system for the cubesat class satellites almost exclusively conforms to a centralized architecture.

This thesis researches the potential of using a distributed architecture for the cubesat power system. There are several key advantages of a distributed architecture that …


Inkjet-Printed Highly Transparent Solar Cell Antennas, Jesus A. Arellano Dec 2011

Inkjet-Printed Highly Transparent Solar Cell Antennas, Jesus A. Arellano

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Small satellites, especially Cube Satellites (CubeSats), have become important vehicles for space exploration. One of the challenges CubeSats face is limited surface area. This limitation poses a question for antenna design–where to mount the antenna? Transparent antenna is a solution to resolve the competition between solar cells and antennas for surface area. The transparent antennas can be directly integrated on top of solar cells without requiring additional space. It is for this reason that this thesis focuses on the integration of highly transparent meshed antenna with solar cells. Even though transparent antennas allow light to travel light through them, they …


Prediction Models For Estimation Of Soil Moisture Content, Swathi Gorthi Dec 2011

Prediction Models For Estimation Of Soil Moisture Content, Swathi Gorthi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Center for Self-Organizing Intelligent Systems (CSOIS) has been successful in developing personal remote sensing systems. These systems can be further enhanced to monitor important resources of earth such as soil moisture content. Soil moisture is the major component of the soil in relation to plant growth. Soil water dissolves salts and makes up the soil solution, which is important as medium for supply of nutrients to growing plants.

Usually, measuring such physical quantities would include using derived formulas that mathematically describe the relationships between the parameters involved. With the advancements in computer modeling, other methods such as empirical modeling …


Autonomous Aerial Manipulation Using A Quadrotor, Vaibhav Ghadiok Aug 2011

Autonomous Aerial Manipulation Using A Quadrotor, Vaibhav Ghadiok

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This paper presents an implementation of autonomous indoor aerial gripping using a low-cost, custom-built quadrotor. Such research extends the typical functionality of micro air vehicles (MAV) from passive observation and sensing to dynamic interaction with the environment. To achieve this, three major challenges are overcome: precise positioning, sensing and manipulation of the object, and stabilization in the presence of disturbance due to interaction with the object. Navigation in both indoor and outdoor unstructured, Global Positioning System-denied (GPS-denied) environments is achieved using a visual Simultaneous Localization and Mapping (SLAM) algorithm that relies on an onboard monocular camera. A secondary camera, capable …


A Two-Dimensional Numerical Simulation Of Plasma Wake Structure Around A Cubesat, Rajendra Mitharwal Aug 2011

A Two-Dimensional Numerical Simulation Of Plasma Wake Structure Around A Cubesat, Rajendra Mitharwal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A numerical model was developed to understand the time evolution of a wake structure around a CubeSat moving in a plasma with transonic speed. A cubeSat operates in the F2 layer of ionosphere with an altitude of 300 − 600 Km. The average plasma density varies between 10−6cm−3 − 10−9cm−3 and the temperature of ions and electrons is found between 0.1−0.2 eV. The study of a wake structure can provide insights for its effects on the measurements obtained from space instruments. The CubeSat is modeled to have a metal surface, which is a realistic …


Document Flash Thermography, Cory A. Larsen Aug 2011

Document Flash Thermography, Cory A. Larsen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis presents the application of ash thermography techniques to the analysis of documents. The motivation for this research is to develop the ability to non-destructively reveal covered writings in archaeological artifacts such as the Codex Selden or Egyptian car- tonnage. Current common signal processing techniques are evaluated for their effectiveness in enhancing subsurface writings found within a set of test documents. These processing techniques include: false colorization, contrast stretching, histogram equalization, median altering, Gaussian low-pass altering, layered signal reconstruction and thermal signal reconstruction (TSR), several contrast image definitions, differential absolute contrast (DAC), correlated contrast, derivative images, principal component thermography …


Cognitive Formation Flight In Multi-Unmanned Aerial Vehicle-Based Personal Remote Sensing Systems, Long Di Aug 2011

Cognitive Formation Flight In Multi-Unmanned Aerial Vehicle-Based Personal Remote Sensing Systems, Long Di

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This work introduces a design and implementation of using multiple unmanned aerial vehicles (UAVs) to achieve cooperative formation flight based on the personal remote sensing platforms developed by the author and the colleagues in the Center for Self-Organizing and Intelligent Systems (CSOIS). The main research objective is to simulate the multiple UAV system, design a multi-agent controller to achieve simulated formation flight with formation reconfiguration and real-time controller tuning functions, implement the control system on actual UAV platforms and demonstrate the control strategy and various formation scenarios in practical flight tests. Research combines analysis on flight control stabilities, develop- ment …


Automatic Merging Of Lidar Point-Clouds Using Data From Low-Cost Gps/Imu Systems, Scott E. Budge, K. Von Niederhausern Jun 2011

Automatic Merging Of Lidar Point-Clouds Using Data From Low-Cost Gps/Imu Systems, Scott E. Budge, K. Von Niederhausern

Electrical and Computer Engineering Faculty Publications

Stationary lidar (Light Detection and Ranging) systems are often used to collect 3-D data (point clouds) that can be used for terrain modelling. The lidar gathers scans which are then merged together to map a terrain. Typically this is done using a variant of the well-known Iterated Closest Point (ICP) algorithm when position and pose of the lidar scanner is not accurately known. One difficulty with the ICP algorithms is that they can give poor results when points that are not common to both scans (outliers) are matched together. With the advent of MEMS (microelectromechanical systems)-based GPS/IMU systems, it is …


Development Of A Reconfigurable Multi-Faceted Communications Device Using Partial Dynamic Reconfiguration, Richard Dunkley May 2011

Development Of A Reconfigurable Multi-Faceted Communications Device Using Partial Dynamic Reconfiguration, Richard Dunkley

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Supporting a variety of communication protocols has typically required extensive hard- ware and Input/Output (I/O) interfaces targeting each protocol specifically. Recent designs in the past ten years have created more dynamic approaches by using Field Programmable Gate Arrays (FPGAs) and embedded hardware to implement or simulate previous hardware I/O designs. With the constant increase in FPGA and embedded technologies the capabilities of dynamic implementations have expanded. This report addresses the design of an up-to-date reconfigurable multi-faceted embedded device targeting recent technological advances in FPGAs.


Model-Based Stripmap Synthetic Aperture Radar Processing, Roger D. West May 2011

Model-Based Stripmap Synthetic Aperture Radar Processing, Roger D. West

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Synthetic aperture radar (SAR) is a type of remote sensor that provides its own illumination and is capable of forming high resolution images of the reflectivity of a scene. The reflectivity of the scene that is measured is dependent on the choice of carrier frequency; different carrier frequencies will yield different images of the same scene.

There are different modes for SAR sensors; two common modes are spotlight mode and stripmap mode. Furthermore, SAR sensors can either be continuously transmitting a signal, or they can transmit a pulse at some pulse repetition frequency (PRF). The work in this dissertation is …


Signal Processing On Digitized Ladar Waveforms For Enhanced Resolution On Surface Edges, Kevin D. Neilsen May 2011

Signal Processing On Digitized Ladar Waveforms For Enhanced Resolution On Surface Edges, Kevin D. Neilsen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Automatic target recognition (ATR) relies on images from various sensors including 3-D imaging ladar. The accuracy of recognizing a target is highly dependent on the number of points on the target. The highest spatial frequencies of a target are located on edges. Therefore, a higher sampling density is desirable at these locations. A ladar receiver captures information on edges by detecting two surfaces when the beam lands partially on one surface and partially on another if the distance between the surfaces is greater than the temporal pulse width of the laser.

In recent years, the ability to digitize the intensity …


Enhancing Multispectral Imagery Of Ancient Documents, Trace A. Griffiths May 2011

Enhancing Multispectral Imagery Of Ancient Documents, Trace A. Griffiths

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Multispectral imaging (MSI) provides a wealth of imagery data that, together with modern signal processing techniques, facilitates the enhancement of document images. In this thesis, four topic areas are reviewed and applied to ancient documents. They are image fusion, matched filters, bleed-through removal, and shadow removal. These four areas of focus provide useful tools for papyrologists studying the digital imagery of documents. The results presented form a strong case for the utility of MSI data over the use of a single image captured at any given wavelength of light.


Perching Using A Quadrotor With Onboard Sensing, Jeremy C. Goldin May 2011

Perching Using A Quadrotor With Onboard Sensing, Jeremy C. Goldin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis presents an implementation of autonomous indoor perching using only onboard sensors on a low-cost, custom-built quadrotor. The perching aggressive maneuver is representative of a class of control problems for aerobatics that requires an agile and robust control system for maneuvering accurately at high speeds. Such research extends the typical functionality of micro air vehicles (MAV) from low speed and stationary observation to dynamic aerobatic transitions for broader operational capabilities including confined landings and evasive maneuvering. To achieve this, three major challenges are overcome: precise and real-time positioning, sensing of the perch and path to the perch, and control …


Design Of An Adaptable Run-Time Reconfigurable Software-Defined Radio Processing Architecture, Joshua R. Templin Dec 2010

Design Of An Adaptable Run-Time Reconfigurable Software-Defined Radio Processing Architecture, Joshua R. Templin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Processing power is a key technical challenge holding back the development of a high-performance software defined radio (SDR). Traditionally, SDR has utilized digital signal processors (DSPs), but increasingly complex algorithms, higher data rates, and multi-tasking needs have exceed the processing capabilities of modern DSPs. Reconfigurable computers, such as field-programmable gate arrays (FPGAs), are popular alternatives because of their performance gains over software for streaming data applications like SDR. However, FPGAs have not yet realized the ideal SDR because architectures have not fully utilized their partial reconfiguration (PR) capabilities to bring needed flexibility. A reconfigurable processor architecture is proposed that utilizes …


Analysis Of Field Programmable Gate Array-Based Kalman Filter Architectures, Arvind Sudarsanam Dec 2010

Analysis Of Field Programmable Gate Array-Based Kalman Filter Architectures, Arvind Sudarsanam

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A Field Programmable Gate Array (FPGA)-based Polymorphic Faddeev Systolic Array (PolyFSA) architecture is proposed to accelerate an Extended Kalman Filter (EKF) algorithm. A system architecture comprising a software processor as the host processor, a hardware controller, a cache-based memory sub-system, and the proposed PolyFSA as co-processor, is presented. PolyFSA-based system architecture is implemented on a Xilinx Virtex 4 family of FPGAs. Results indicate significant speed-ups for the proposed architecture when compared against a space-based software processor. This dissertation proposes a comprehensive architecture analysis that is comprised of (i) error analysis, (ii) performance analysis, and (iii) area analysis. Results are presented …


Complexity And Power Consumption In Stochastic Iterative Decoders, Keyur M. Payak Dec 2010

Complexity And Power Consumption In Stochastic Iterative Decoders, Keyur M. Payak

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Stochastic iterative decoding is a novel method to decode the bits received at the end of a communication channel and to control the rate of error happening in the message bits due to noise being injected into the channel. This decoder uses stochastic computation that is based on manipulation of probabilities from a random sequence of digital bits. Hardware needed for implementing this arithmetic is very simple and can be completely implemented using simple digital complementary metal oxide gates. This helps the decoder to be technology independent, which is a major advantage over its digital and analog counterparts, which are …


Architecture, Modeling, And Analysis Of A Plasma Impedance Probe, Magathi Jayaram Dec 2010

Architecture, Modeling, And Analysis Of A Plasma Impedance Probe, Magathi Jayaram

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Variations in ionospheric plasma density can cause large amplitude and phase changes in the radio waves passing through this region. Ionospheric weather can have detrimental effects on several communication systems, including radars, navigation systems such as the Global Positioning Sytem (GPS), and high-frequency communications. As a result, creating models of the ionospheric density is of paramount interest to scientists working in the field of satellite communication.

Numerous empirical and theoretical models have been developed to study the upper atmosphere climatology and weather. Multiple measurements of plasma density over a region are of marked importance while creating these models. The lack …


Incorporating Spatial Information Into Gas Plume Detection In Hyperspectral Imagery, Cameron S. Grant Dec 2010

Incorporating Spatial Information Into Gas Plume Detection In Hyperspectral Imagery, Cameron S. Grant

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Detection of chemical plumes in hyperspectral data is a problem having solutions that focus on spectral information. These solutions neglect the presence of the spatial information in the scene. The spatial information is exploited in this work by assignment of prior probabilities to neighborhood configurations of signal presence or absence. These probabilities are leveraged in a total probability approach to testing for signal presence in a pixel of interest. The two new algorithms developed are named spatial information detection enhancement (SIDE) and bolt-on SIDE (B-SIDE). The results are explored in comparison to the clutter matched filter (CMF), a standard spectral …


Autonomous Security Patrol System, Jake Erramouspe May 2010

Autonomous Security Patrol System, Jake Erramouspe

Undergraduate Honors Capstone Projects

This project provides an efficient and cost-effective solution to building security and active monitoring. The security is monitored and controlled by autonomous patrol robots. Any indication of a security breach will result in an immediate alarm and activation of the robot group to subdue and tranquilize the intruder.


Micronetworking: Reliable Communication On 3d Integrated Circuits, Andres A. Contreras May 2010

Micronetworking: Reliable Communication On 3d Integrated Circuits, Andres A. Contreras

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The potential failure in through-silicon vias (TSVs) still poses a challenge in trying to extend the useful life of a 3D integrated circuit (IC). A model is proposed to mitigate the communication problem in 3D integrated circuits caused by the breaks at the TSVs. We provide the details of a low-complexity network that takes advantages of redundant TSVs to make it possible to re-route around breaks and maintain effective communication between layers. Different configurations for the micronetwork are analyzed and discussed. We also present an evaluation of the micronetwork's performance, which turns out to be quite promising, based on several …


A Finite Domain Constraint Approach For Placement And Routing Of Coarse-Grained Reconfigurable Architectures, Rohit Saraswat May 2010

A Finite Domain Constraint Approach For Placement And Routing Of Coarse-Grained Reconfigurable Architectures, Rohit Saraswat

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Scheduling, placement, and routing are important steps in Very Large Scale Integration (VLSI) design. Researchers have developed numerous techniques to solve placement and routing problems. As the complexity of Application Specific Integrated Circuits (ASICs) increased over the past decades, so did the demand for improved place and route techniques. The primary objective of these place and route approaches has typically been wirelength minimization due to its impact on signal delay and design performance. With the advent of Field Programmable Gate Arrays (FPGAs), the same place and route techniques were applied to FPGA-based design. However, traditional place and route techniques may …


Wavelets As A De-Noising Approach Of Cartilage Displacement Field Determined By Mri, David Francisco Toribio Carvajal May 2010

Wavelets As A De-Noising Approach Of Cartilage Displacement Field Determined By Mri, David Francisco Toribio Carvajal

Undergraduate Honors Capstone Projects

Tissue engineering was once categorized as a subfield of biomaterials, but having grown in scope and importance, it can be considered as a field in its own right. Tissue engineering studies the mechanical properties of tissues and the applications that repair or replace portions of or whole tissues. The analyses of the mechanical properties of tissues can help in the diagnosis of tissue diseases and in the monitoring of the progress of tissue treatments and replacements.

In order to study the mechanical properties of tissues, it is often required to repeatedly compress and decompress the tissue. This deformation process helps …


Analog Front-End Design Using The Gm/Id Method For A Pulse-Based Plasma Impedance Probe System, Arun J. Rao May 2010

Analog Front-End Design Using The Gm/Id Method For A Pulse-Based Plasma Impedance Probe System, Arun J. Rao

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Plasma Impedance Probe (PIP) is an electronic instrument that measures the impedance of a dipole antenna immersed in a plasma environment. Measurements made by the PIP provide valuable information regarding the plasma environment. Knowledge of ionospheric plasma density and density disturbances is required to understand radio frequency communication with satellites. The impedance curve provides us with significant plasma characteristics such as the electron-neutral collision frequency and plasma electron density.

The work proposed here is a transistor-level implementation of the analog front-end, the non-inverting amplifier that is used to drive the antenna. The antenna immersed in plasma is excited with …


Transmitter Localization Using Autonomous Robotic Swarms, Joshua S. Adams May 2010

Transmitter Localization Using Autonomous Robotic Swarms, Joshua S. Adams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this research is to design a proof of concept system that is capable of locating a hidden radio transmitter and to investigate methods of multi-agent formation control with a specific interest in the effectiveness of these methods on the overall objective of locating this transmitter. A system is proposed and developed in which autonomous agents work together to locate this transmitter and their responsiveness is analyzed while using formations based both on a behavioral system and a system derived from centroidal Voronoi tessellations. Many software adaptations to the existing MASnet program are required, as well as some …