Engineering Commons^™

Embedding The Behavior Macromodel Into Tdie For Transient Field-Circuit Simulations, Huan Huan Zhang, Li (Lijun) Jun Jiang, He Ming Yao

Electrical and Computer Engineering Faculty Research & Creative Works

A novel transient field-circuit simulation method based on the time-domain integral equation (TDIE) and circuit macromodels is proposed. The traditional field-circuit simulation process constructs Kirchoff's equations for linear or nonlinear lumped circuits, which cannot handle problems with unknown circuit structure. The proposed method creates parametric behavior macromodels to represent the port constitutive relations of the circuits. Artificial neural network technique is adopted to estimate the model parameters based on the known port voltages and currents. Then, the obtained macromodel is coupled with TDIE that describes the behavior of electromagnetic subsystem to form the equations of a whole system, which can …

Nitrogen Rate And Landscape Impacts On Life Cycle Energy Use And Emissions From Switchgrass-Derived Ethanol, Eric G. Mbonimpa, Sandeep Kumar, Vance N. Owens, Rajesh Chintala, Heidi L. Sieverding, James J. Stone

Faculty Publications

Switchgrass-derived ethanol has been proposed as an alternative to fossil fuels to improve sustainability of the US energy sector. In this study, life cycle analysis (LCA) was used to estimate the environmental benefits of this fuel. To better define the LCA environmental impacts associated with fertilization rates and farm-landscape topography, results from a controlled experiment were analyzed. Data from switchgrass plots planted in 2008, consistently managed with three nitrogen rates (0, 56, and 112 kg N ha−1), two landscape positions (shoulder and footslope), and harvested annually (starting in 2009, the year after planting) through 2014 were used as input into …

Multi-Sensor Integration To Map Odor Distribution For The Detection Of Chemical Sources, Xiang Gao, Levent Acar

Electrical and Computer Engineering Faculty Research & Creative Works

This paper addresses the problem of mapping odor distribution derived from a chemical source using multi-sensor integration and reasoning system design. Odor localization is the problem of finding the source of an odor or other volatile chemical. Most localization methods require a mobile vehicle to follow an odor plume along its entire path, which is time consuming and may be especially difficult in a cluttered environment. To solve both of the above challenges, this paper proposes a novel algorithm that combines data from odor and anemometer sensors, and combine sensors' data at different positions. Initially, a multi-sensor integration method, together …

Attenuation Of The Ganglion Cell Layer In A Premature Infant Revealed With Handheld Spectral Domain Optical Coherence Tomography, Mara R. Goldberg, Fouad R. Zakka, Joseph Carroll, Deborah M. Costakos

Biomedical Engineering Faculty Research and Publications

Purpose: To report on subclinical retinal abnormalities shown through handheld spectral domain optical coherence tomography on a premature infant.

Methods: Case report.

Results: The initial and follow-up exams on a premature infant revealed severely attenuated ganglion cell and nerve fiber layers. There was cystoid macular edema in both eyes at the initial visits, which resolved by the 1-year follow-up.

Discussion: Optical coherence tomography can reveal significant retinal abnormalities in premature infants which are not detectable through funduscopic exam. Documenting such findings may be useful for the comprehensive management of vision problems in children with a history of premature birth.

Mercator (Mapping Enumerator For Cuda) User's Manual, Stephen V. Cole, Jeremy Buhler

All Computer Science and Engineering Research

Welcome to the MERCATOR user's manual! MERCATOR is a CUDA/C++ system designed to assist you in writing efficient CUDA applications by automatically generating significant portions of the GPU-side application code. We hope you find it helpful; please feel free to contact the authors with any questions or feedback.

In-Network Retransmissions In Named Data Networking, Hila Ben Abraham, Patrick Crowley

All Computer Science and Engineering Research

The strategy layer is an important architectural component in both Content-Centric Networking (CCN) and Named Data Networking (NDN). This component introduces a new forwarding model that allows an application to configure its namespace with a forwarding strategy. A core mechanism in every forwarding strategy is the decision of whether to retransmit an unsatisfied Interest or to wait for an application retransmission. While some applications request control of all retransmissions, others rely on the assumption that the strategy will retransmit an Interest when it is not satisfied. Although an application can select the forwarding strategy used in the local host, it …

Carbon Nanotube Based Groundwater Remediation: The Case Of Trichloroethylene, Kshitij C. Jha, Zhuonan Liu, Hema Vijwani, Mallikarjuna Nadagouda, Sharmila M. Mukhopadhyay, Mesfin Tsige

Mechanical and Materials Engineering Faculty Publications

Adsorption of chlorinated organic contaminants (COCs) on carbon nanotubes (CNTs) has been gaining ground as a remedial platform for groundwater treatment. Applications depend on our mechanistic understanding of COC adsorption on CNTs. This paper lays out the nature of competing interactions at play in hybrid, membrane, and pure CNT based systems and presents results with the perspective of existing gaps in design strategies. First, current remediation approaches to trichloroethylene (TCE), the most ubiquitous of the COCs, is presented along with examination of forces contributing to adsorption of analogous contaminants at the molecular level. Second, we present results on TCE adsorption …

The Experiment And Analysis Of Active Mechanisms For Enhancing Heat And Mass Transfer In Sorption Fluids, Ziqi Shen

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

This project was funded by American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE RP-1462). It is a three years’ research, including the literature review, labs construction, experiments and data analysis.

In this thesis, first of all, we conducted literature review of mechanism motion influence on heat and mass transfer and additive effect in absorption chiller. This part helps us understand the basic idea of how mechanism motion affects the heat and mass transfer of sorption fluids and gives us reference on how to select the experiment instrument and the experiment operation range.

In the second part, the instrument selection …

Industrial Robot Trajectory Stiffness Mapping For Hybrid Manufacturing Process, Z. Wang, R. Liu, X. Chen, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Data Driven Nonparametric Detection, Weiguang Wang

Dissertations - ALL

The major goal of signal detection is to distinguish between hypotheses about the state of events based on observations. Typically, signal detection can be categorized into centralized detection, where all observed data are available for making decision, and decentralized detection, where only quantized data from distributed sensors are forwarded to a fusion center for decision making. While these problems have been intensively studied under parametric and semi-parametric models with underlying distributions being fully or partially known, nonparametric scenarios are not well understood yet. This thesis mainly explores nonparametric models with unknown underlying distributions as well as semi-parametric models as an …

Response Of Mercury In A Forest Stream To Lime Application: Accelerated Watershed Recovery, Geoffrey Dean Millard

Dissertations - ALL

Following decreases in acid deposition, some impacted surface waters in northern Europe and the northeastern USA are beginning to recover. The resultant increases in pH in these waters has coincided with increased dissolved organic carbon concentrations, which is also correlated with increases in both total mercury and methylmercury concentrations. Understanding how ecosystem mercury dynamics respond to recovery from acid deposition has important implications for fisheries and human exposure. Honnedaga Lake is one of seven lakes in the Adirondack Park of New York State with a heritage Brook trout (Salvelinus fontinalis) population, making the bioavailability and trophic transfer of mercury (Hg) …

Optimal Inference For Distributed Detection, Earnest Akofor

Dissertations - ALL

In distributed detection, there does not exist an automatic way of generating optimal decision strategies for non-affine decision functions. Consequently, in a detection problem based on a non-affine decision function, establishing optimality of a given decision strategy, such as a generalized likelihood ratio test, is often difficult or even impossible.

In this thesis we develop a novel detection network optimization technique that can be used to determine necessary and sufficient conditions for optimality in distributed detection for which the underlying objective function is monotonic and convex in probabilistic decision strategies. Our developed approach leverages on basic concepts of optimization and …

Choosing Creativity: The Role Of Individual Risk And Ambiguity Aversion On Creative Concept Selection In Engineering Design, Christine Toh, Scarlett R. Miller

Interdisciplinary Informatics Faculty Publications

While creativity is often seen as an indispensable quality of engineering design, individuals often select conventional or previously successful options during the concept selection process due to the inherent risk associated with creative concepts and their inadvertent bias against creativity. However, little is actually known about what factors attribute to the promotion or filtering of these creative concepts during concept selection. To address this knowledge gap, an exploratory study was conducted with 38 undergraduate engineering students. This study was aimed at investigating the impact of individual risk aversion, ambiguity aversion, and student educational level on the selection and filtering of …

Correlating Interlaminar Fatigue Fracture Behavior To Nde Parameters In Carbon/Epoxy Composites Containing Voids And Delamination, Issa Hakim, Norbert Meyendorf, Steven L. Donaldson, René Laquai, David Walter, Bernd Müller, Paul Graja

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Carbon fiber composites have been increasingly used in aerospace, military, sports, automotive and other fields due to their excellent properties, including high specific strength, high specific modulus, corrosion resistance, fatigue resistance, and low thermal expansion coefficient. Delamination, or interlaminar fracture, is a serious failure mode leading to a loss in composite stiffness and strength. Manufacturing process defects such as voids degrade the fatigue life and delamination resistance of the composite. This study investigates the effect of voids on fatigue interlaminar fracture behavior of carbon fiber composites. Samples with different vacuum levels: 0%, 50% and 100% were fabricated by varying the …

Fault Resilient And Reconfigurable Power Management Using Photovoltaic Integrated With Cmos Switches, Rakeshkumar Mahto

Electrical and Computer Engineering ETDs

A Photovoltaic (PV) cell is a device which converts light incident upon it to electric current. The push for green energy due to global warming and diminution of fossil fuels opens up a huge market for PV cells. Hence, a lot of interest is being garnered for using PV cells for various applications. However, a PV module's performance degrades due to many anomalies such as failure of individual PV cell within a module, the opening of interconnection, a short circuit in the connection, failure of bypass diode, failure in voltage regulator or partial shading. To some extent all of these …

Diagnostic Ultrasound High Mechanical Index Impulses Restore Microvascular Flow In Peripheral Arterial Thromboembolism, T. R. Porter, S. Radio, J. Lof, E. Carr Everbach, J. E. Powers, J. E. Powers, F. Vignon, W. T. Shi, F. Xie

Engineering Faculty Works

We sought to explore mechanistically how intermittent high-mechanical-index (MI) diagnostic ultrasound impulses restore microvascular flow. Thrombotic microvascular obstruction was created in the rat hindlimb muscle of 36 rats. A diagnostic transducer confirmed occlusion with low-MI imaging during an intravenous microbubble infusion. This same transducer was used to intermittently apply ultrasound with an MI that produced stable or inertial cavitation (IC) for 10 min through a tissue-mimicking phantom. A nitric oxide inhibitor, L-Nω-nitroarginine methyl ester (L-NAME), was pre-administered to six rats. Plateau microvascular contrast intensity quantified skeletal microvascular blood volume, and postmortem staining was used to detect perivascular hemorrhage. Intermittent IC …

Impact Of A Reverse Delta Type Add-On Device On The Flap-Tip Vortex Of A Wing, Afaq Altaf, Tan Boon Thong, Ashraf Ali Omar, Waqar Asrar

International Journal of Aviation, Aeronautics, and Aerospace

The effect of interactions of vortices produced by an outboard flap-tip of a half-span wing (NACA 23012 in landing configuration) and a slender reverse delta type add-on device, placed in the proximity of the outboard flap-tip, on the upper surface of the half-span wing is investigated using Particle Image Velocimetry in a closed loop low speed wind tunnel. Specifically the characteristics of the vortex interactions generated downstream in planes perpendicular to the free stream direction and their dependence on angles of attack at a chord-based Reynolds number of Re_c=2.75×10⁵ have been determined. It was found that the …

Recognition Of Smoking Gesture Using Smart Watch Technology, Casey A. Cole, Bethany Janos, Dien Anshari, James Thrasher, Scott Strayer, Homayoun Valafar

Faculty Publications

Diseases resulting from prolonged smoking are the most common preventable causes of death in the world today. In this report we investigate the success of utilizing accelerometer sensors in smart watches to identify smoking gestures. Early identification of smoking gestures can help to initiate the appropriate intervention method and prevent relapses in smoking. Our experiments indicate 85%-95% success rates in identification of smoking gesture among other similar gestures using Artificial Neural Networks (ANNs). Our investigations concluded that information obtained from the x-dimension of accelerometers is the best means of identifying the smoking gesture, while y and z dimensions are helpful …

Secure And Lightweight Hardware Authentication Using Isolated Physical Unclonable Function, Mehrdad Zaker Shahrak

School of Computing: Dissertations, Theses, and Student Research

As embedded computers become ubiquitous, mobile and more integrated in connectivity, user dependence on integrated circuits (ICs) increases massively for handling security sensitive tasks as well as processing sensitive information. During this process, hardware authentication is important to prevent unauthorized users or devices from gaining access to secret information. An effective method for hardware authentication is by using physical unclonable function (PUF), which is a hardware design that leverages intrinsic unique physical characteristics of an IC, such as propagation delay, for security authentication in real time. However, PUF is vulnerable to modeling attacks, as one can design an algorithm to …

Simulation Model Of An Automatic Commercial Ice Machine, Haithem Murgham, David Myszka, Vijay Bahel, Rajan Rajendran, Kurt Knapke, Suresh Shivashankar, Kyaw Wynn

Mechanical and Aerospace Engineering Faculty Publications

Automatic commercial ice-making machines that produce a batch of cube ice at regular intervals are known as “cubers." Such machines are commonly used in food service, food preservation, hotel, and health service industries. The machines are typically rated for the weight of ice produced over a 24-hour period at ambient air temperatures of 90°F and water inlet temperature of 70°F.

These cubers typically utilize an air-cooled, vapor-compression cycle to freeze circulating water flowing over an evaporator grid. Once a sufficient amount ice is formed, a valve switches to enable a harvest mode, where the compressor’s discharge gas is routed into …

Automated Measurement Of Fracture Callus In Radiographs Using Portable Software, Stephen M. Porter, Hannah L. Dailey, Katharine A. Hollar, Karina Klein, James A. Harty, Trevor J. Lujan

Mechanical and Biomedical Engineering Faculty Publications and Presentations

The development of software applications that assist the radiographic evaluation of fracture healing could advance clinical diagnosis and expedite the identification of effective treatment strategies. A radiographic feature regularly used as an outcome measure for basic and clinical fracture healing research is new bone growth, or fracture callus. In this study, we developed OrthoRead, a portable software application that uses image-processing algorithms to detect and measure fracture callus in plain radiographs. OrthoRead utilizes an optimal boundary tracking algorithm to semi-automatically segment the cortical surface, and a novel iterative thresholding selection algorithm to then automatically segment the fracture callus. The software …

Examining Bridges Between Informal And Formal Learning Environments: A Sequential Mixed Method Design, Dagen L. Valentine

Department of Agricultural Leadership, Education, and Communication: Dissertations, Theses, and Student Research

The purpose of this sequential mixed method study was to identify schools implementing a technology-based engineering design intervention in a way that connects or bridges formal learning environments of the school-day to informal learning environments such as afterschool programs. Further, this study investigated educators’ decisions that enabled or facilitated bridging between formal and informal learning environments. This cooperation and/or linking between informal and formal learning time is bridging. Participants included public schools (n=16) in Eastern Nebraska that incorporated the Nebraska Wearables Technology (WearTec) program at their school, club or Out-of-School-Time program during the 2015-2016 school year. Three of the schools …

Flight Control And Hardware Design Of Multi-Rotor Systems, Nathan M. Zimmerman

Master's Theses (2009 -)

This thesis overviews crucial concepts involved in achieving quadcopter flight such as orientation estimation and control system implementation. This thesis also presents researchers with comprehensive hardware and software specifications for a quadcopter system. The primary application for this system would be for research with regards to the implementation of advance control techniques as well as data acquisition. Key constructs of this system include hardware software specifications for a flight controller, the radio system, and the sensorless brushless motor controllers. Firstly, the thesis starts by developing a reference frame and a mathematical model for the quadcotper system. Next, flight orientation estimation …

Mims: Mobile Interruption Management System, Mohammad Kayes Kaykobad

Master's Theses (2009 -)

Mobile devices are increasing in an astronomical rate throughout the world. While it is bringing a lot of comfort to the users it is not coming without any hazards. Now a user is susceptible to mobile call interruptions wherever he is, whether he is in the middle of a very important discussion or in a very important task like performing a complicated emergency operation in a hospital. As a result researchers have been studying to find ways to minimize cost of mobile interruptions. In this thesis we have proposed a mobile interruption management system in which callers have been grouped …

Functional Comparison Of Conventional Afos With The Dynamic Response Afo, Mitchell Ruble

Master's Theses (2009 -)

Ankle foot orthoses (AFOs) are commonly prescribed to provide stability and foot clearance for patients with weakened or injured musculature. The Dynamic Response AFO (DRAFO) was designed to improve proprioception at heel strike. The design includes a rigid outer shell with a cut out heel and a soft inner lining; it is typically aligned in plantarflexion and may incorporate external heel wedges. The objective of this study was to investigate the effects of the DRAFO design features and contrast its biomechanical function with that of conventional locked and articulating AFOs. The research hypotheses were: 1) DRAFO-assisted gait parameters (e.g. ankle …

Analysis And Synthesis Of A Planar Reconfigurable Mechanism With A Variable Joint, Peter William Malak

Master's Theses (2009 -)

Currently, there is a demand for mechanisms with variable topology that can perform multiple tasks with the least amount of actuators. These devices have the ability to provide numerous motion profiles within one device. In the following thesis, a specific planar reconfigurable mechanism with a kinematic reconfigurable joint was mathematically modeled. This mechanism functions as a RRRP mechanism in one configuration and as a RRRR in the other and is known as a RRRR-RRRP Mechanism. The kinematics and kinetics of the RRRR-RRRP Mechanism were analyzed with a Lagrangian approach. The models are simulated and verified using a trajectory planner and …

An Interactive Likelihood For The Multi-Bernoulli Filter, Anthony B. Hoak

Master's Theses (2009 -)

In this thesis, a simple yet effective technique is presented for increasing the accuracy of multi-target tracking algorithms with a focus on sequential Monte-Carlo implementations of random finite set-based approaches. This technique, referred to throughout this work as an interactive likelihood, exploits the spatial information that exists in any given measurement, reducing the need for data association and allowing for more target interaction thereby increasing overall tracking accuracy. The interactive likelihood is constructed entirely within the random finite set framework and is integrated with a multi-Bernoulli filter. In addition, a state-of-the-art deep neural network for pedestrian detection is combined in …

Phytovolatilization Of Organic Contaminants, Matt Limmer, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Plants can interact with a variety of organic compounds, and thereby affect the fate and transport of many environmental contaminants. Volatile organic compounds may be volatilized from stems or leaves (direct phytovolatilization) or from soil due to plant root activities (indirect phytovolatilization). Fluxes of contaminants volatilizing from plants are important across scales ranging from local contaminant spills to global fluxes of methane emanating from ecosystems biochemically reducing organic carbon. In this article past studies are reviewed to clearly differentiate between direct- and indirect-phytovolatilization and we discuss the plant physiology driving phytovolatilization in different ecosystems. Current measurement techniques are also described, …

Managing Contingencies In Smart Grids Via The Internet Of Things, Stefano Ciavarella, Jhi Young Joo, Simone Silvestri

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a framework for contingency management using smart loads, which are realized through the emerging paradigm of the Internet of things. The framework involves the system operator, the load serving entities (LSEs), and the end-users with smart home management systems that automatically control adjustable loads. The system operator uses an efficient linear equation solver to quickly calculate the load curtailment needed at each bus to relieve congested lines after a contingency. Given this curtailment request, an LSE calculates a power allowance for each of its end-use customers to maximize the aggregate user utility. This large-scale NP-hard problem is …

Secure Massive Mimo Transmission With An Active Eavesdropper, Yongpeng Wu, Robert Schober, Derrick Wing Kwan Ng, Chengshan Xiao, Giuseppe Caire

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we investigate secure and reliable transmission strategies for multi-cell multi-user massive multiple-input multiple-output systems with a multi-Antenna active eavesdropper. We consider a time-division duplex system where uplink training is required, and an active eavesdropper can attack the training phase to cause pilot contamination at the transmitter. This forces the precoder used in the subsequent downlink transmission phase to implicitly beamform toward the eavesdropper, thus increasing its received signal power. Assuming matched filter precoding and artificial noise (AN) generation at the transmitter, we derive an asymptotic achievable secrecy rate when the number of transmit antennas approaches infinity. For …