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Full-Text Articles in Engineering

Mems Variable Area Capacitor For Room Temperature Electrometry, George C. Underwood, Tod V. Laurvick Nov 2018

Mems Variable Area Capacitor For Room Temperature Electrometry, George C. Underwood, Tod V. Laurvick

Faculty Publications

This paper introduces a new way to detect charge using MEMS variable capacitors for extremely sensitive, room temperature electrometry. It is largely based on the electrometers introduced by Riehl et al. [1] except variable capacitance is created by a changing area, not a changing gap. The new scheme will improve MEMS electrometers by eliminating the effects of squeeze-film damping and by theoretically increasing the maximum charge resolution by 70%. The charge conversion gain (the increase in output voltage per input unit charge) for this system is derived. The result show good agreement with MATLAB calculations.


Evaluation Of Eu:Licaf For Neutron Detection Utilizing Sipms And Portable Electronics, Michael A. Ford, Buckley E. O'Day Iii, John W. Mcclory, Manish K. Sharma, Areg Danagoulian Nov 2018

Evaluation Of Eu:Licaf For Neutron Detection Utilizing Sipms And Portable Electronics, Michael A. Ford, Buckley E. O'Day Iii, John W. Mcclory, Manish K. Sharma, Areg Danagoulian

Faculty Publications

With the increasing cost and decreasing availability of 3He, there have been many efforts to find alternative neutron detection materials. Lithium calcium aluminum fluoride (LiCAF) enriched to 95% 6Li doped with europium was evaluated here as a replacement material for 3He. Wafers 0.5 cm thick, consisting of LiCAF crystals in a rubberized matrix, were embedded with wavelength shifting fibers (WSF) and mated to silicon photo-multipliers (SiPMs) to measure the photon response in a flux of neutrons from a DD neutron generator. Excellent discrimination was realized between neutrons and gammas, and both pulse-height discrimination and pulse-shape analysis were …


Development Of A Placement Exam To Increase Student Success In A Junior Level Circuits And Systems Class, David Parent Oct 2018

Development Of A Placement Exam To Increase Student Success In A Junior Level Circuits And Systems Class, David Parent

Faculty Publications

In this work, which is intended to be a Full Paper in the Innovative Practice Category, the implementation of an improved placement exam that increased the pass rate in a junior level systems course in the author’s electrical engineering department by 15% is presented. For almost 30 years the author’s EE department has used a face to face exam to place students in a junior level circuits and systems course or into a review workshop. The details of the exam and suggestions about future use in conjunction MyOpenMath analytics to increase student success are also given.


Examination The Impact Of Various Factors On Student Success In An Introduction To Circuit Analysis Course, David Parent Oct 2018

Examination The Impact Of Various Factors On Student Success In An Introduction To Circuit Analysis Course, David Parent

Faculty Publications

In this work in progress, several models to predict student success in a sophomore introduction to circuit analysis class were created based on prior grade point average, grade in a pre-requisite physics class, the semester the pre-requisite physics class was taken, the number of units a student was taking, the number of times a student repeated the circuits class, and the number of times a student repeated any class prior to enrollment. While all models were statistically significant, the model that included prior GPA and the grade in a pre-requisite physics was the most significant for the data collection effort. …


Integration Of An Electrical Engineering Capstone Course With Social Justice And Global Studies, David Parent, Patricia Backer Oct 2018

Integration Of An Electrical Engineering Capstone Course With Social Justice And Global Studies, David Parent, Patricia Backer

Faculty Publications

A four course package (six units total) consisting of two general education (GE) classes and two electrical engineering capstone classes that are taught in a highly integrated manner, that not only meets university GE requirements, but also meets the new ABET criteria in which the need to address a societal need is embedded with design criteria. The prompts for the new integrated GE/capstone Assessment results are also presented, along with methods to increase student motivation for studying GE.


Wireless Sensor Networks For Long-Term Monitoring Of Urban Noise, Courtney Peckens, Cédric Porter, Taylor Rink Sep 2018

Wireless Sensor Networks For Long-Term Monitoring Of Urban Noise, Courtney Peckens, Cédric Porter, Taylor Rink

Faculty Publications

Noise pollution in urban environments is becoming increasingly common and it has potential to negatively impact people’s health and decrease overall productivity. In order to alleviate these effects, it is important to better quantify noise patterns and levels through data collection and analysis. Wireless sensor networks offer a method for achieving this with a higher level of granularity than traditional handheld devices. In this study, a wireless sensing unit (WSU) was developed that possesses the same functionality as a handheld sound level meter. The WSU is comprised of a microcontroller unit that enables on-board computations, a wireless transceiver that uses …


Relative Navigation: A Keyframe-Based Approach For Observable Gps-Degraded Navigation, David O. Wheeler, Daniel P. Koch, James S. Jackson, Timothy W. Mclain, Randal W. Beard Jul 2018

Relative Navigation: A Keyframe-Based Approach For Observable Gps-Degraded Navigation, David O. Wheeler, Daniel P. Koch, James S. Jackson, Timothy W. Mclain, Randal W. Beard

Faculty Publications

State estimation for micro air vehicles (MAVs) often depends heavily on reliable global measurements such as GPS. When global measurements are unavailable, additional sensors, such as cameras or laser scanners, are commonly used to provide measurements of the MAV’s translation and rotation relative to a previously observed keyframe image or scan. With the use of only relative sensors, however, the global position and heading of the vehicle are unobservable and cannot be reliably reconstructed. Many existing approaches work with respect to a global reference frame, resulting in a loss of state observability. This article highlights that unobservability leads to inconsistency …


Non-Gnss Smartphone Pedestrian Navigation Using Barometric Elevation And Digital Map-Matching, Daniel Broyles, Kyle J. Kauffman, John F. Raquet, Piotr Smagowski Jul 2018

Non-Gnss Smartphone Pedestrian Navigation Using Barometric Elevation And Digital Map-Matching, Daniel Broyles, Kyle J. Kauffman, John F. Raquet, Piotr Smagowski

Faculty Publications

Pedestrian navigation in outdoor environments where global navigation satellite systems (GNSS) are unavailable is a challenging problem. Existing technologies that have attempted to address this problemoften require external reference signals or specialized hardware, the extra size,weight, power, and cost of which are unsuitable for many applications. This article presents a real-time, self-contained outdoor navigation application that uses only the existing sensors on a smartphone in conjunction with a preloaded digital elevation map. The core algorithm implements a particle filter, which fuses sensor data with a stochastic pedestrian motion model to predict the user’s position. The smartphone’s barometric elevation is then …


A Neuromorphic Quadratic, Integrate, And Fire Silicon Neuron With Adaptive Gain, David Parent, Eric Basham Jul 2018

A Neuromorphic Quadratic, Integrate, And Fire Silicon Neuron With Adaptive Gain, David Parent, Eric Basham

Faculty Publications

An integrated circuit implementation of a silicon neuron was designed, manufactured, and tested. The circuit was designed using the Quadratic, Integrate, and Fire (QIF) neuron model in 0.5 µm silicon technology. The neuron implementation was optimized for low current consumption, drawing only 1.56 mA per QIF circuit and utilized hysteretic reset, non-inverting integrator, and voltage-squarer circuits. The final area of each circuit in silicon was 268 µm height × 400 µm width. This design is the first IC of its kind for this neuron model and is successfully able to output true spiking that follows the behaviors of bistability, monotonic, …


Improvements For Vision-Based Navigation Of Small, Fixed-Wing Unmanned Aerial Vehicles, Robert C. Leishman, Jeremy Gray, John F. Raquet, Adam Rutkowski Jul 2018

Improvements For Vision-Based Navigation Of Small, Fixed-Wing Unmanned Aerial Vehicles, Robert C. Leishman, Jeremy Gray, John F. Raquet, Adam Rutkowski

Faculty Publications

Investigating alternative navigation approaches for use when GPS signals are unavailable is an active area of research across the globe. In this paper we focus on the navigation of small, fixed-wing unmanned aerial vehicles (UAVs) that employ vision-based approaches combined with other measurements as a replacement for GPS. We demonstrate with flight test data that vehicle attitude information, derived from cheap, MEMS-based IMUs is sufficient to improve two different types of vision processing algorithms. Secondly, we show analytically and with flight test data that range measurements to one other vehicle with global pose is sufficient to constrain the global drift …


Photovoltaic System Optimization For An Austere Location Using Time Series Data, Torrey J. Wagner, Eric Lang, Warren Assink, Douglas S. Dudis Jun 2018

Photovoltaic System Optimization For An Austere Location Using Time Series Data, Torrey J. Wagner, Eric Lang, Warren Assink, Douglas S. Dudis

Faculty Publications

In this work we test experimental photovoltaic, storage and generator technologies and investigate their potential to meet austere location energy needs. After defining the energy requirements and insolation of a 1,100-person base, we develop a microgrid model and simulation. Cost optimizations were then performed using hourly time-series data to explore the cost and performance trade-space of a PV-battery-generator system. The work highlights the cost of resiliency and the dependencies of optimum system component sizes on duration and the fully burdened cost of fuel.


Range Information Characterization Of The Hokuyo Ust-20lx Lidar Sensor, Matthew A. Cooper, John F. Raquet, Rick Patton May 2018

Range Information Characterization Of The Hokuyo Ust-20lx Lidar Sensor, Matthew A. Cooper, John F. Raquet, Rick Patton

Faculty Publications

This paper presents a study on the data measurements that the Hokuyo UST-20LX Laser Rangefinder produces, which compiles into an overall characterization of the LiDAR sensor relative to indoor environments. The range measurements, beam divergence, angular resolution, error effect due to some common painted and wooden surfaces, and the error due to target surface orientation are analyzed. It was shown that using a statistical average of sensor measurements provides a more accurate range measurement. It was also shown that the major source of errors for the Hokuyo UST-20LX sensor was caused by something that will be referred to as “mixed …


Quantification Of The Impact Of Photon Distinguishability On Measurement-Device- Independent Quantum Key Distribution, Garrett K. Simon, Blake K. Huff, William M. Meier, Logan O. Mailloux, Lee E. Harrell Apr 2018

Quantification Of The Impact Of Photon Distinguishability On Measurement-Device- Independent Quantum Key Distribution, Garrett K. Simon, Blake K. Huff, William M. Meier, Logan O. Mailloux, Lee E. Harrell

Faculty Publications

Measurement-Device-Independent Quantum Key Distribution (MDI-QKD) is a two-photon protocol devised to eliminate eavesdropping attacks that interrogate or control the detector in realized quantum key distribution systems. In MDI-QKD, the measurements are carried out by an untrusted third party, and the measurement results are announced openly. Knowledge or control of the measurement results gives the third party no information about the secret key. Error-free implementation of the MDI-QKD protocol requires the crypto-communicating parties, Alice and Bob, to independently prepare and transmit single photons that are physically indistinguishable, with the possible exception of their polarization states. In this paper, we apply the …


Demonstration Of Versatile Whispering-Gallery Micro-Lasers For Remote Refractive Index Sensing, Lei Wan, Hengky Chandrahalim, Jian Zhou Mar 2018

Demonstration Of Versatile Whispering-Gallery Micro-Lasers For Remote Refractive Index Sensing, Lei Wan, Hengky Chandrahalim, Jian Zhou

Faculty Publications

We developed chip-scale remote refractive index sensors based on Rhodamine 6G (R6G)-doped polymer micro-ring lasers. The chemical, temperature, and mechanical sturdiness of the fused-silica host guaranteed a flexible deployment of dye-doped polymers for refractive index sensing. The introduction of the dye as gain medium demonstrated the feasibility of remote sensing based on the free-space optics measurement setup. Compared to the R6G-doped TZ-001, the lasing behavior of R6G-doped SU-8 polymer micro-ring laser under an aqueous environment had a narrower spectrum linewidth, producing the minimum detectable refractive index change of 4 x 10−4 RIU. The maximum bulk refractive index sensitivity (BRIS) …


Monte Carlo Simulations Of Three-Dimensional Electromagnetic Gaussian Schell-Model Sources, Milo W. Hyde Iv, Santasri Bose-Pillai, Olga Korotkova Feb 2018

Monte Carlo Simulations Of Three-Dimensional Electromagnetic Gaussian Schell-Model Sources, Milo W. Hyde Iv, Santasri Bose-Pillai, Olga Korotkova

Faculty Publications

This article presents a method to simulate a three-dimensional (3D) electromagnetic Gaussian-Schell model (EGSM) source with desired characteristics. Using the complex screen method, originally developed for the synthesis of two-dimensional stochastic electromagnetic fields, a set of equations is derived which relate the desired 3D source characteristics to those of the statistics of the random complex screen. From these equations and the 3D EGSM source realizability conditions, a single criterion is derived, which when satisfied guarantees both the realizability and simulatability of the desired 3D EGSM source. Lastly, a 3D EGSM source, with specified properties, is simulated; the Monte Carlo simulation …


3d Printed High Density, Reversible, Chip-To-Chip Microfluidic Interconnects, Hua Gong, Adam T. Woolley, Gregory P. Nordin Feb 2018

3d Printed High Density, Reversible, Chip-To-Chip Microfluidic Interconnects, Hua Gong, Adam T. Woolley, Gregory P. Nordin

Faculty Publications

Our latest developments in miniaturizing 3D printed microfluidics [Gong et al., Lab Chip, 2016, 16, 2450; Gong et al., Lab Chip, 2017, 17, 2899] offer the opportunity to fabricate highly integrated chips that measure only a few mm on a side. For such small chips, an interconnection method is needed to provide the necessary world-to-chip reagent and pneumatic connections. In this paper, we introduce simple integrated microgaskets (SIMs) and controlled-compression integrated microgaskets (CCIMs) to connect a small device chip to a larger interface chip that implements world-to-chip connections. SIMs or CCIMs are directly 3D printed as part of the device …


Metastable Ar(1s5) Density Dependence On Pressure And Argon-Helium Mixture In A High Pressure Radio Frequency Dielectric Barrier Discharge, Daniel J. Emmons, David E. Weeks, Ben Eshel, Glen P. Perram Jan 2018

Metastable Ar(1s5) Density Dependence On Pressure And Argon-Helium Mixture In A High Pressure Radio Frequency Dielectric Barrier Discharge, Daniel J. Emmons, David E. Weeks, Ben Eshel, Glen P. Perram

Faculty Publications

Simulations of an α-mode radio frequency dielectric barrier discharge are performed for varying mixtures of argon and helium at pressures ranging from 200 to 500 Torr using both zero and one-dimensional models. Metastable densities are analyzed as a function of argon-helium mixture and pressure to determine the optimal conditions, maximizing metastable density for use in an optically pumped rare gas laser. Argon fractions corresponding to the peak metastable densities are found to be pressure dependent, shifting from approximately 15% Ar in He at 200 Torr to 10% at 500 Torr. A decrease in metastable density is observed as pressure …


Effects Of Edge Inclination Angles On Whispering-Gallery Modes In Printable Wedge Microdisk Lasers, Cong Chen, Lei Wan, Hengky Chandrahalim Jan 2018

Effects Of Edge Inclination Angles On Whispering-Gallery Modes In Printable Wedge Microdisk Lasers, Cong Chen, Lei Wan, Hengky Chandrahalim

Faculty Publications

The ink-jet technique was developed to print the wedge polymer microdisk lasers. The characterization of these lasers was implemented using a free-space optics measurement setup. It was found that disks of larger edge inclination angles have a larger free spectral range (FSR) and a lower resonance wavelength difference between the fundamental transverse electric (TE) and transverse magnetic (TM) whispering-gallery modes (WGMs). This behavior was also confirmed with simulations based on the modified Oxborrow’s model with perfectly matched layers (PMLs), which was adopted to accurately calculate the eigenfrequencies, electric field distributions, and quality parameters of modes in the axisymmetric microdisk resonators. …


A Survey Of Digital Systems Curriculum And Pedagogy In Electrical And Computer Engineering Programs, Hector A. Ochoa, Mukul V. Shirvaikar Jan 2018

A Survey Of Digital Systems Curriculum And Pedagogy In Electrical And Computer Engineering Programs, Hector A. Ochoa, Mukul V. Shirvaikar

Faculty Publications

Digital Systems is one of the basic foundational courses in Electrical and Computer Engineering. One of the challenges in designing and modifying the curriculum for the course is the fast pace of technology change in the area. TTL chips that were in vogue with students building physical circuits, have given way to new paradigms like FPGA based synthesis with hardware description languages such as VHDL. However, updating a course is not as simple as just changing the book, and changing the syllabus. A large amount of work needs to be done in terms of selecting the book that will accommodate …


Evaluating Smartphones For Infrastructure Work Order Management, Victor L. Guinn, Brent T. Langhals, John J. Elshaw Jan 2018

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 …