Engineering Commons^™

Reducing Run-Time Adaptation Space Via Analysis Of Possible Utility Bounds, Clay Stevens, Hamid Bagheri

School of Computing: Conference and Workshop Papers

Self-adaptive systems often employ dynamic programming or similar techniques to select optimal adaptations at run-time. These techniques suffer from the “curse of dimensionality", increasing the cost of run-time adaptation decisions. We propose a novel approach that improves upon the state-of-the-art proactive self-adaptation techniques to reduce the number of possible adaptations that need be considered for each run-time adaptation decision. The approach, realized in a tool called Thallium, employs a combination of automated formal modeling techniques to (i) analyze a structural model of the system showing which configurations are reachable from other configurations and (ii) compute the utility that can be …

A Quantile-Based Approach For Transmission Expansion Planning, Jairo Cervantes, F. Fred Choobineh

Department of Electrical and Computer Engineering: Faculty Publications

Transmission expansion planning is an integral part of power system planning and consists of generating and selecting transmission proposals for maintaining sufficient transmission capacity to satisfy the electric load. Specifically, the desire to increase the use of renewable energy has exposed the limitations of transmission networks and has elevated the importance of transmission expansion planning. However, considering the random nature of renewable sources in conjunction with the power outages makes the planning process very challenging. We present a new procedure for selecting the best transmission enhancement proposal from a set of finite proposals under uncertainty. The selection is based on …

Joint-Srvdnet: Joint Super Resolution And Vehicle Detection Network, Moktari Mostofa, Syeda Nyma Ferdous, Benjamin S. Riggan, Nasser M. Nasrabadi

Department of Electrical and Computer Engineering: Faculty Publications

In many domestic and military applications, aerial vehicle detection and super-resolution algorithms are frequently developed and applied independently. However, aerial vehicle detection on super resolved images remains a challenging task due to the lack of discriminative information in the super-resolved images. To address this problem, we propose a Joint Super-Resolution and Vehicle Detection Network (Joint SRVDNet) that tries to generate discriminative, high-resolution images of vehicles from low-resolution aerial images. First, aerial images are up-scaled by a factor of 4x using a Multi-scale Generative Adversarial Network (MsGAN), which has multiple intermediate outputs with increasing resolutions. Second, a detector is trained on …

Stochastic Simulation Of Cellular Metabolism, Emalie J. Clement, Thomas T. Schulze, Ghada A. Soliman, Beata Joanna Wysocki, Paul H. Davis, Tadeusz A. Wysocki

Department of Electrical and Computer Engineering: Faculty Publications

Increased technological methods have enabled the investigation of biology at nanoscale levels. Such systems require the use of computational methods to comprehend the complex interactions that occur. The dynamics of metabolic systems have been traditionally described utilizing differential equations without fully capturing the heterogeneity of biological systems. Stochastic modeling approaches have recently emerged with the capacity to incorporate the statistical properties of such systems. However, the processing of stochastic algorithms is a computationally intensive task with intrinsic limitations. Alternatively, the queueing theory approach, historically used in the evaluation of telecommunication networks, can significantly reduce the computational power required to generate …

Nonlinear Dynamic Tests Of A Reinforced Concrete Frame Building At Different Damage Levels, Seyedsina Yousefianmoghadam, Mingming Song, Mohammad E. Mohammadi, Brittany Packard, Andreas Stavridis, Babak Moaveni, Richard L. Wood

Department of Civil and Environmental Engineering: Faculty Publications

This paper discusses the dynamic tests of a two-story infilled reinforced concrete (RC) frame building using an eccentric-mass shaker. The building, located in El Centro, CA, was substantially damaged prior to the tests due to the seismic activity in the area. During the testing sequence, five infill walls were removed to introduce additional damage states and to investigate the changes in the dynamic properties and the nonlinear response of the building to the induced excitations. The accelerations and displacements of the structure under the forced and ambient vibrations were recorded through an array of sensors, while lidar scans were obtained …

Understanding Eye Gaze Patterns In Code Comprehension, Jonathan Saddler

School of Computing: Dissertations, Theses, and Student Research

Program comprehension is a sub-field of software engineering that seeks to understand how developers understand programs. Comprehension acts as a starting point for many software engineering tasks such as bug fixing, refactoring, and feature creation. The dissertation presents a series of empirical studies to understand how developers comprehend software in realistic settings. The unique aspect of this work is the use of eye tracking equipment to gather fine-grained detailed information of what developers look at in software artifacts while they perform realistic tasks in an environment familiar to them, namely a context including both the Integrated Development Environment (Eclipse or …

Small Mode Volume Plasmonic Film-Coupled Nanostar Resonators, Negar Charchi, Ying Li, Margaret Huber, Elyahb Allie Kwizera, Xiaohua Huang, Christos Argyropoulos, Thang Hoang

Department of Electrical and Computer Engineering: Faculty Publications

Confining and controlling light in extreme subwavelength scales are tantalizing tasks. In this work, we report a study of individual plasmonic film-coupled nanostar resonators where polarized plasmonic optical modes are trapped in ultrasmall volumes. Individual gold nanostars, separated from a flat gold film by a thin dielectric spacer layer, exhibit a strong light confinement between the sub-10 nm volume of the nanostar's tips and the film. Through dark field scattering measurements of many individual nanostars, a statistical observation of the scattered spectra is obtained and compared with extensive simulation data to reveal the origins of the resonant peaks. We observe …

Extracellular Matrix Disparities In An Nkx2-5 Mutant Mouse Model Of Congenital Heart Disease, Deanna Bousalis, Christopher S. Lacko, Nora Hlavac, Fariz Alkassis, Rebecca A. Wachs, Sahba Mobini, Christine E. Schmidt, Hideko Kasahara

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Congenital heart disease (CHD) affects almost one percent of all live births. Despite diagnostic and surgical reparative advances, the causes and mechanisms of CHD are still primarily unknown. The extracellular matrix plays a large role in cell communication, function, and differentiation, and therefore likely plays a role in disease development and pathophysiology. Cell adhesion and gap junction proteins, such as integrins and connexins, are also essential to cellular communication and behavior, and could interact directly (integrins) or indirectly (connexins) with the extracellular matrix. In this work, we explore disparities in the expression and spatial patterning of extracellular matrix, adhesion, and …

Deep Learning And Polar Transformation To Achieve A Novel Adaptive Automatic Modulation Classification Framework, Pejman Ghasemzadeh

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Automatic modulation classification (AMC) is an approach that can be leveraged to identify an observed signal's most likely employed modulation scheme without any a priori knowledge of the intercepted signal. Of the three primary approaches proposed in literature, which are likelihood-based, distribution test-based, and feature-based (FB), the latter is considered to be the most promising approach for real-world implementations due to its favorable computational complexity and classification accuracy. FB AMC is comprised of two stages: feature extraction and labeling. In this thesis, we enhance the FB approach in both stages. In the feature extraction stage, we propose a new architecture …

Riveted Steel Railway Bridge Health Monitoring And Damage Detection, Ahmed Rageh

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Visual inspection is often used to assess the condition of railway bridges at discrete points in time, an approach that can be subjective and possibly unsafe. Alternatively, certain bridges have their condition assessed via the installation of a large number of sensors. These sensors can be costly to place, power and maintain. Therefore, reducing their numbers and maximizing the extracted information is of utmost importance. In addition, evaluating bridge condition from measured response can be quite challenging due to loading and environmental variations, especially when a limited number of sensors are used.

The focus of this research is to develop …

Development Of An In Vitro Intervertebral Disc Innervation Model To Screen Neuroinhibitory Biomaterials, Sarah M. Romereim, Caleb A. Johnston, Adan L. Redwine,, Rebecca A. Wachs

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Pain originating from an intervertebral disc (discogenic pain) is a major source of chronic low back pain. Pathological innervation of the disc by pain‐sensing nerve fibers is thought to be a key component of discogenic pain, so treatment with biomaterials that have the ability to inhibit neurite growth will greatly benefit novel disc therapeutics. Currently, disc therapeutic biomaterials are rarely screened for their ability to modulate nerve growth, mainly due to a lack of models to screen neuromodulation. To address this deficit, our lab has engineered a three dimensional in vitro disc innervation model that mimics the interface between primary …

Water-Energy-Food Linkages In Shared Smallholder Irrigation Schemes, Ankit Chandra

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Irrigation is a policy focus in Sub-Saharan Africa and is viewed as an important mechanism to improve farmers’ income and livelihoods while reducing the impacts of climate change. Water, energy, and food are linked in intricate ways in irrigated agriculture, and understanding the interplay of these components is crucial for sustainable and profitable crop production. Although studies have been conducted in different parts of the world to understand water and energy use at a field scale under large irrigation systems, little is known about linkages under farmer-managed mechanized irrigated schemes in Sub-Saharan Africa. This study evaluates water-energy-food linkages, engineering and …

Using Infrared Radiometry Thermometer For Irrigation Management Of Dry Edible Beans In Western Nebraska, Isabella Presotto Possignolo

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Proper irrigation management requires farmers to determine the right timing and amount to irrigate. Soil water sensors are one of the most popular sensor-based approach used by farmers to decide when and how much to irrigate. However, installation and retrieval of soil water sensors require excavation of soil and can be challenging. Other than soil water sensors, there are plant-based water stress monitoring technologies that are less soil disturbing such as infrared radiometry thermometer (IRT). Using canopy temperature measured from IRT, researchers can calculate thermal-based indices such as crop water stress index (CWSI) for many crops around the world. Yet …

Evaluation Of The Dynamic Behavior Of Steel Staircases With Concrete Filled Pan Treads, Tyler Sondag

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

Vibration serviceability of staircases has been a growing challenge for structural engineers due to changing materials and structural forms. In order to prevent or correct serviceability problems due to structural vibrations, structural engineers should be able to predict the dynamic performance of a staircase structure. However, there are few technical guides available for designing steel staircases, and the ones that do exist are often limited in their applications. Currently, there is a lack of research on staircases that are less prone to vibrations, such as staircases with concrete filled pans that are composed of face and wall stringers. Therefore, the …

Application Of An Ultrasonic Sensor To Monitor Soil Erosion And Deposition, Jessica E. Johnson

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

While erosion and deposition are naturally occurring processes, these processes can be accelerated by human influences. The acceleration of erosion causes damage to human assets and costs billions of dollars to mitigate. Monitoring erosion at high resolutions can provide researchers and managers the data necessary to help manage erosion. Current erosion monitoring methods tend to be invasive to the area, record low frequency measurements, have a narrow spatial range of measurement, or are very expensive. There is a need for an affordable monitoring system capable of monitoring erosion and deposition non-invasively at a high resolution. The objectives of this research …

Ten Questions Concerning Well-Being In The Built Environment, Sergio Altomonte, Joseph Allen, Philomena M. Bluyssen, Gail Brager, Lisa Heschong, Angela Loder, Stefano Schiavon, Jennifer A. Veitch, Lily M. Wang, Pawel Wargocki

Durham School of Architectural Engineering and Construction: Faculty Publications

Well-being in the built environment is a topic that features frequently in building standards and certification schemes, in scholarly articles and in the general press. However, despite this surge in attention, there are still many questions on how to effectively design, measure, and nurture well-being in the built environment. Bringing together experts from academia and the building industry, this paper aims to demonstrate that the promotion of well-being requires a departure from conventional agendas. The ten questions and answers have been arranged to offer a range of perspectives on the principles and strategies that can better sustain the consideration of …

Nitrate And Herbicides Removal From Groundwater Using Immobilized Algae, Sara Mollamohammada

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

To improve crop yield and control broadleaf weeds, many farmers apply nitrate-based fertilizers and chemical herbicides to their fields. Excessive use of these chemicals can cause contamination in waterbodies and impact on the public health. The physical and chemical methods have been suggested to remove these herbicides are usually costly. In this study, the capability of immobilized algal beads in removing nitrate and several herbicides of environmental concern from synthetic and actual groundwater and surface water was evaluated.

The experiments were performed in batch, sequencing batch and continuous flow modes and the effect of different operational conditions (light intensity, cultivation …

In-Service Performance Evaluation Of Concrete Sloped End Treatments In Iowa, Jessica Lingenfelter

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Sloped end treatments were historically developed as low-cost, low-maintenance end treatments for rigid features like concrete barriers and bridge rails. Crash testing indicated that sloped end treatments are associated with significant instability for impacting vehicles. However, the in-service performance of these features has not been evaluated. An in-service performance evaluation (ISPE) was performed to evaluate vehicle crashes with sloped end treatments in Iowa between 2008 and 2017. Researchers generated a geographic inventory of sloped end treatment locations, reviewed crash narratives and scene diagrams for crashes near these sloped end treatments, and calculated an estimated crash rate and crash cost for …

Emotional Awareness During Bug Fixes: A Pilot Study, Jada O. Loro, Abigail L. Schneff, Sarah J. Oran, Bonita Sharif

School of Computing: Dissertations, Theses, and Student Research

This study examines the effects of a programmer's emotional awareness on progress while fixing bugs. The goal of the study is to capitalize on emotional awareness to ultimately increase progress made during software development. This process could result in improved software maintenance.

Sediment Outflow Under Simulated Rainfall Conditions With Varying Geotechnical Properties, Pranjay Joshi, Akhilesh Kumar, P. V. Singh, Jahangeer Jahangeer

Daugherty Water for Food Global Institute: Faculty Publications

The vulnerability of soil toward erosion might be reduced by having a good vegetative cover over the soil surface, slope improvement, and improving soil properties so that it is not easily detached and transported. However, the establishment of proper vegetative cover is a long process because it takes time for seeds to germinate and attain maturity. As an alternative approach, if soil resistance was increased by increasing the shear strength of soil against erosive forces offered by eroding agents, the soil system would become capable of withstanding the detachment of its particles on the application of shear stress. To achieve …

Optimizing Athletic Throwing Power For Increased Training Efficiency, Ian Ghanavati, Curtis Tomasevicz

UCARE: Research Products

A summary on the investigation of the mechanics of weighted baseball pitching.

• The demand for higher pitch velocity has increased at all levels of competitive play within baseball • Weighted baseball training programs are a common way to increase pitch velocity • The efficacy and safety of weighted ball throwing is not fully understood • The aim of this study is to further investigate the mechanics of pitching under and overweight balls in order to better understand their role in athletic training

Development Of A Novel Vehicle Guidance System: Vehicle Risk Mitigation And Control, Michael Sweigard

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Over a half of fatal vehicular crashes occur due to vehicles leaving their designated travel lane and entering other lanes or leaving the roadway. Lane departure accidents also result in billions of dollars in cost to society. Recent vehicle technology research into driver assistance and vehicle autonomy has developed to assume various driving tasks. However, these systems are do not work for all roads and travel conditions. The purpose of this research study was to begin the development a novel vehicle guidance approach, specifically studying how the vehicle interacts with the system to detect departures and control the vehicle

A …

Upgrading Cracking Waste To Rubber Precursors Via Oxidative Dehydrogenation, Andrew Mason, Delaney Franck, Firdvas Nasimov, Lindsey Jarema, Gitau Wambugu

Department of Chemical and Biomolecular Engineering: Funded Proposals

To: Dr. Yasar Demirel, Professor, University of Nebraska-Lincoln

As the result of process changes within an ethylene cracking plant, the amount of a C4 byproduct waste stream has significantly increased (Fabiano, Nedwick 1999). A system of extractive distillation and catalytic oxidative dehydrogenation can be used to add value to this C4 waste stream by producing high purity 1,3-Butadiene, an important rubber precursor. 1,3-Butadiene is a critical component of multiple consumer goods, including automobile tires and synthetic rubber and has a steadily increasing demand, reaching 10 million metric tons in 2012 (Biddy, Scarlata, Kinchin, 2016). The simulation assumes a feed flow …

Nanomechanical Characterization Of Fuel Cell Ionomers, Jackson Goddard

UCARE: Research Products

Energy sustainability can be achieved by improving and adopting clean energy technologies, and a better nanoscale understanding of ionomer-catalyst layers could lead to increased efficiency of proton exchange membrane fuel cells. Samples of Nafion ( Perfluorosulfonic acid ionomer) and PFIA (Perfluoroimide acid ionomer) of varying film thickness were prepared and then studied using contact resonance force microscopy. It was determined that storage and loss modulus increase as relative humidity increases and ionomer film thickness goes below 100 nm. Furthermore, in this specific study, the similar storage and loss modulus of Nafion and PFIA could be attributed to similar backbone structure …

Synthetic Lethality In Pediatric Brain Cancer Cells By Optimized Plga Nanoparticles And Drug Combinations, Megan Ruckman, Megan Otte, Forrest Kievit

UCARE: Research Products

Here we test drugs effectiveness to inhibit various DNA repair pathways with the purpose of sensitizing cancer cells to radiotherapy. We work on optimizing delivery of DNA repair pathway inhibiting drugs by the use of PLGA nanoparticles.

Evaluation And Update Of Mash Test Vehicles, Kellon B. Ronspies

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The Manual for Assessing Safety Hardware (MASH) requires full-scale crash testing of roadside features using worst practical impact conditions. Vehicle selection for full-scale crash testing is intended to be representative of the contemporary passenger vehicle fleet. Researchers at the Midwest Roadside Safety Facility (MwRSF) investigated attributes of passenger vehicle sales to determine if the vehicle selection criteria shown in MASH should be revised to accommodate changes in the vehicle fleet. A methodology was considered to affordably re-analyze the vehicle fleet when necessary to ensure MASH vehicle selection criteria are reflective of vehicles currently on roadways.

Representative vehicles were documented using …

Reliability-Calibrated Ann-Based Load And Resistance Factor Load Rating For Steel Girder Bridges, Francisco Garcia

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

This research aimed to develop a supplemental ANN-based tool to support the Nebraska Department of Transportation (NDOT) in optimizing bridge management investments when choosing between refined modeling, field testing, retrofitting, or bridge replacement. ANNs require an initial investment to collect data and train a network, but offer future benefits of speed and accessibility to engineers utilizing the trained ANN in the future. As the population of rural bridges in the Midwest approaching the end of their design service lives increases, Departments of Transportation are under mounting pressure to balance safety of the traveling public with fiscal constraints. While it is …

Evaluation Of Low-Cost Depth Cameras For Agricultural Applications, Isabella C.F.S. Condotta, Tami M. Brown-Bandl, Santosh Pitla, John P. Stinn, Késia O. Silva-Miranda

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Low-cost depth-cameras have been used in many agricultural applications with reported advantages of low cost, reliability and speed of measurement. However, some problems were also reported and seem to be technology related, so understanding the limitations of each type of depth camera technology could provide a basis for technology selection and the development of research involving its use. The cameras use one or a combination of two of the three available technologies: structured light, time-of-flight (ToF), and stereoscopy. The objectives were to evaluate these different technologies for depth sensing, including measuring accuracy and repeatability of distance data and measurements at …

An Eye Tracking Replication Study Of A Randomized Controlled Trial On The Effects Of Embedded Computer Language Switching, Cole Peterson

School of Computing: Dissertations, Theses, and Student Research

The use of multiple programming languages (polyglot programming) during software development is common practice in modern software development. However, not much is known about how the use of these different languages affects developer productivity. The study presented in this thesis replicates a randomized controlled trial that investigates the use of multiple languages in the context of database programming tasks. Participants in our study were given coding tasks written in Java and one of three SQL-like embedded languages: plain SQL in strings, Java methods only, a hybrid embedded language that was more similar to Java. In addition to recording the online …

Research Tools And Their Uses For Determining The Thermal Inactivation Kinetics Of Salmonella In Low-Moisture Foods, Soon Kiat Lau

Department of Food Science and Technology: Dissertations, Theses, and Student Research

The reputation of low-moisture foods as safe foods has been crumbling over the past decade due to repeated involvement in foodborne illness outbreaks. Although various pasteurization technologies exist, a majority are thermal processes and have not been well-characterized for pasteurizing low-moisture foods. In addition, the nature of a low-moisture food matrix introduces various experimental complications that are not encountered in high-moisture foods. In this dissertation, the development, building instructions, and characterization of various open source tools for studying the inactivation kinetics of microorganisms in low-moisture foods are described. The first tool is the TDT Sandwich, a dry heating device for …