Engineering Commons^™

Compositional Reasoning For Shared-Variable Concurrent Programs, Fuyuan Zhang, Yongwang Zhao, David Sanan, Yang Liu, Alwen Tiu, Shang-Wei Lin, Jun Sun

Research Collection School Of Computing and Information Systems

Scalable and automatic formal verification for concurrent systems is always demanding. In this paper, we propose a verification framework to support automated compositional reasoning for concurrent programs with shared variables. Our framework models concurrent programs as succinct automata and supports the verification of multiple important properties. Safety verification and simulations of succinct automata are parallel compositional, and safety properties of succinct automata are preserved under refinements. We generate succinct automata from infinite state concurrent programs in an automated manner. Furthermore, we propose the first automated approach to checking rely-guarantee based simulations between infinite state concurrent programs. We have prototyped our …

A Unified Approach To Route Planning For Shared Mobility, Yongxin Tong, Yuxiang Zeng, Zimu Zhou, Lei Chen, Jieping Ye, Ke Xu

Research Collection School Of Computing and Information Systems

There has been a dramatic growth of shared mobility applications such as ride-sharing, food delivery and crowdsourced parcel delivery. Shared mobility refers to transportation services that are shared among users, where a central issue is route planning. Given a set of workers and requests, route planning finds for each worker a route, i.e., a sequence of locations to pick up and drop off passengers/parcels that arrive from time to time, with different optimization objectives. Previous studies lack practicability due to their conflicted objectives and inefficiency in inserting a new request into a route, a basic operation called insertion. In this …

Characteristics And Applications Of Biochars Derived From Wastewater Solids, Zhongzhe Liu, Simcha L. Singer, Yiran Tong, Lee Kimball, Erik Anderson, Matthew Hughes, Daniel Zitomer, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Pyrolysis is a thermochemical decomposition process that can be used to generate pyrolysis gas (py-gas), bio-oil, and biochar as well as energy from biomass. Biomass from agricultural waste and other plant-based materials has been the predominant pyrolysis research focus. Water resource recovery facilities also produce biomass, referred to as wastewater solids, that could be a viable pyrolysis feedstock. Water resource recovery facilities are central collection and production sites for wastewater solids. While the utilization of biochar from a variety of biomass types has been extensively studied, the utilization of wastewater biochars has not been reviewed in detail. This review compares …

Economic Development In Nonmetropolitan Nebraska: Internet Use, Nature-Based Tourism, Federal Tax Policy And Workforce Development: 2018 Nebraska Rural Poll Results, Rebecca J. Vogt, Cheryl A. Burkhart-Kriesel, Randolph L. Cantrell, Bradley Lubben, L. J. Mcelravy, Timothy Meyer

Rural Futures Institute: Publications

Conclusion

The proportion of rural Nebraskans accessing the Internet using their cell phone has increased compared to two years ago. But, the proportion subscribing to high-speed Internet service at home remained stable during the past two years. Persons living in or near the smallest communities are less likely than persons living in or near larger communities to have high-speed Internet service at home.

Not many rural Nebraskans report significant limitations from their home Internet service on their ability to do most tasks. At least one in ten report being limited significantly or not being able to play real time video …

A Nonlinear Crack Model For Concrete Structure Based On An Extended Scaled Boundary Finite Element Method, Jian-Bo Li, Xin Gao, Xing-An Fu, Chenglin Wu, Gao Lin

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Fracture mechanics is one of the most important approaches to structural safety analysis. Modeling the fracture process zone (FPZ) is critical to understand the nonlinear cracking behavior of heterogeneous quasi-brittle materials such as concrete. In this work, a nonlinear extended scaled boundary finite element method (X-SBFEM) was developed incorporating the cohesive fracture behavior of concrete. This newly developed model consists of an iterative procedure to accurately model the traction distribution within the FPZ accounting for the cohesive interactions between crack surfaces. Numerical validations were conducted on both of the concrete beam and dam structures with various loading conditions. The results …

The Yielding Transition In Periodically Sheared Binary Glasses At Finite Temperature, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

Non-equilibrium molecular dynamics simulations are performed to investigate the dynamic behavior of three-dimensional binary glasses prepared via an instantaneous quench across the glass transition. We found that with increasing strain amplitude up to a critical value, the potential energy approaches lower minima in steady state, whereas the amplitude of shear stress oscillations becomes larger. Below the yielding transition, the storage modulus dominates the mechanical response, and the gradual decay of the potential energy over consecutive cycles is accompanied by reduction in size of transient clusters of atoms with large nonaffine displacements. In contrast, above the yield strain, the loss modulus …

Software For Peak Finding And Elemental Composition Assignment For Glycosaminoglycan Tandem Mass Spectra, John D. Hogan, Joshua A. Klein, Jiandong Wu, Pradeep Chopra, Geert Jan Boons, Luis Carvalho, Cheng Lin, Joseph Zaia

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glycosaminoglycans (GAGs) Covalently Linked to Proteoglycans (PGs) Are Characterized by Repeating Disaccharide Units and Variable Sulfation Patterns Along the Chain. GAG Length and Sulfation Patterns Impact Disease Etiology, Cellular Signaling, and Structural Support for Cells. We and Others Have Demonstrated the Usefulness of Tandem Mass Spectrometry (MS 2 ) for Assigning the Structures of GAG Saccharides; However, Manual Interpretation of Tandem Mass Spectra is Time-Consuming, So Computational Methods Must Be Employed. in the Proteomics Domain, the Identification of Monoisotopic Peaks and Charge States Relies on Algorithms that Use Averagine, or the Average Building Block of the Compound Class Being Analyzed. …

Significant Improvement In Tio₂ Photocatalytic Activity Through Controllable Zro₂ Deposition, Xiaofeng Wang, Rajankumar L. Patel, Xinhua Liang

Chemical and Biochemical Engineering Faculty Research & Creative Works

ZrO₂ was deposited on anatase TiO₂ nanoparticles using 5-80 cycles of atomic layer deposition (ALD). The photocatalytic activity of all samples was evaluated based on the degradation of methylene blue (MB) solution under UV light. The TiO₂ sample with 45 cycles of ZrO₂ deposition (45c-Zr/TiO₂, 1.1 wt% ZrO₂) was proved to be the most efficient catalyst with a degradation kinetic constant 10 times larger than that of the pure TiO₂ sample. All samples were characterized using inductively coupled plasma atomic emission spectroscopy (ICP-AES), nitrogen adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy …

Numerical Modeling Of The Effects Of Land Use Change And Irrigation On Streamflow Depletion Of Frenchman Creek, Nebraska, Moussa Guira

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

A three-dimensional Control Volume Finite Difference-based numerical groundwater flow model was constructed to assess the effects of agricultural irrigation and land use change on streamflow depletion. The study area is Frenchman Creek basin located in southwestern corner of the State of Nebraska, USA. This area was subject to an increased proliferation of groundwater abstraction for agricultural purposes since industrial revolution. It has also been subject to land use change from native rangeland to dry and irrigated cropland. The groundwater flow model was spatially discretized using Voronoi cells in unstructured grid built with the USGS MODFLOW-6. Temporal discretization defined 151 time …

Discontinuous Galerkin Time-Domain Modeling Of Graphene Nanoribbon Incorporating The Spatial Dispersion Effects, Ping Li, Li (Lijun) Jun Jiang, Hakan Bagci

Electrical and Computer Engineering Faculty Research & Creative Works

It is well known that graphene demonstrates spatial dispersion properties, i.e., its conductivity is nonlocal and a function of spectral wavenumber (momentum operator) q. In this paper, to account for effects of spatial dispersion on transmission of high-speed signals along graphene nanoribbon (GNR) interconnects, a discontinuous Galerkin time-domain (DGTD) algorithm is proposed. The atomically thick GNR is modeled using a nonlocal transparent surface impedance boundary condition (SIBC) incorporated into the DGTD scheme. Since the conductivity is a complicated function of q (and one cannot find an analytical Fourier transform pair between q and spatial differential operators), an exact time-domain SIBC …

Methods For Estimating Vehicle Fuel Consumption In Urban Road Networks Using Geographical Attributes, Ryan G. Conrad

Civil and Environmental Engineering Master's Project Reports

This paper presents statistical techniques for estimating vehicle fuel consumption in urban road networks based on vehicle and geographical factors. A routing algorithm utilizing mapping data from OpenStreetMap and elevation data from the Shuttle Radar Topography Mission is presented and used to generate paths that minimize vehicle fuel consumption. The concept of a fuel consumption estimating function is proposed as an extension of the well-known distance-estimating functions that are widely used in logistics planning and research.

Statistical models are developed that estimate fuel consumption in three tested urban areas with vehicle weight, elevation and regional travel speed characteristics being the …

Sonomechanical Enhanced Sparging Techniques For Advanced Reactor Applications, Floren V. Rubio

Nuclear Engineering ETDs

The fluoride salt cooled high temperature reactor (FHR) is a Generation IV advanced reactor design that has potential to produce efficient, low carbon, and safe energy. But, there are significant engineering challenges that need to be addressed before the deployment of this reactor. One of the key challenges is tritium release mitigation and sequestration. Because the FHR utilizes a eutectic LiF-BeF2 (flibe) salt as a coolant, the coolant is a significant source of tritium.

High-power ultrasonics have been used in many industrial process streams such as food processing, metal production, chemical production, and pharmaceutical manufacturing. Techniques and concepts from these …

A Computational Fluid Dynamics Study On The Aerodynamic Performance Of Ram-Air Parachutes, Angelo A. Fonseca Pazmiño

Doctoral Dissertations and Master's Theses

The modeling of a ram-air parachute presents challenges in the prediction of the inflight geometry, as there is a strong interaction between the flow field and parachute structure. This thesis presents the development of a CAD design and CFD methodology to the simulation of ram-air parachutes in steady-state conditions. Starting from a 2D rib drawing, methods were developed to approximate the 3D geometry and efficiently model the parachute as a rigid and impermeable body. The use of distortions was implemented on a 2D, pseudo-2D, and 3D model to enhance their behavior during a real flight. The SST turbulence model was …

A Computational Analysis Of The Aerodynamics And Aeroacoustics Of Jets With Fluid Injection, Marco Coderoni

Doctoral Dissertations and Master's Theses

A detailed numerical analysis of fluidic injection as a tool to reduce noise emission is presented here. The noise reduction strategy, developed at the Pennsylvania State University, is based on injectors that blow air into the diverging section of the nozzle to emulate the effect of interior corrugation on the jet plume. The advantage is that the injection can be activated during takeoff and turned o_ during other phases of flight so that performance is not affected. Numerical simulations are performed on a military-style nozzle based on the GE F400-series engines, with a design Mach number of 1:65, for over-expanded …

Sensitivity Analyses Of Optimized Attitude Estimators Using Sensor Fusion Solutions For Low-Cost Mems Configurations, Ryan W. Hoffman

Doctoral Dissertations and Master's Theses

Since the 1990’s, there has been increased focus on creating navigation systems for small unmanned systems, particularly small unmanned aerial systems (SUAS). Due to size, weight, and cost restrictions, compared to larger more costly manned systems, navigation systems for SUAS have evolved to be quite different from the proven systems of the past. Today, there are many solutions for the problem of navigation for SUAS. The problem has now become choosing the most fitting navigation solution for a given application/mission. This is particularly true for evaluating solutions that are fundamentally different.

This research analyses the performance and sensitivity of four …

Improving Seaglider Efficiency: An Analysis Of Wing Shapes, Hull Morphologies, And Propulsion Methods, Christopher James Hockley

Doctoral Dissertations and Master's Theses

Autonomous underwater gliders are a family of autonomous underwater vehicles used for long-term observation of oceanic environments. These gliders leverage changes in buoyancy and the resulting vertical motion, to generate forward locomotion via hydrodynamic surfaces. In order to function for extended periods, these systems operate in a low-speed, low-drag regime. This research examines factors impacting the operational efficiencies of gliders, including morphological changes, configuration changes, and propulsion. An interesting question arises when considering the operational efficiencies of conventionally propelled systems at the operating speeds typical of gliders. Can a conventional propulsion system match the efficiency of an underwater glider buoyancy …

Determining The Location Of Runway Exits Using Airport Surface Detection Equipment, Christopher Bryan Clemmer

Doctoral Dissertations and Master's Theses

Airport surface detection equipment, such as ASDE-X, is used by thirty-five commercially operated airports throughout the United States. ASDE-X is responsible for the safe monitoring of aircraft movements as well as ground support vehicle operating on the airfield. Like most radar-based technologies, ASDE-X can report the position of any aircraft within a one second time interval. This data not only contains the geographic position, but also reports speed, heading, altitude, and aircraft specific characteristics. Using a quantitative approach, this research will use the data reported by ASDE-X to analyze current runway exit locations and develop an improved method of determining …

General Aviation Pilot Acceptance And Adoption Of Electronic Flight Bag Technology, Troy Ernest Techau

Doctoral Dissertations and Master's Theses

This research used an adapted version of the extended Unified Theory of Acceptance and Use of Technology (UTAUT2) to examine electronic flight bag (EFB) acceptance and adoption for general aviation (GA) pilots. EFBs are a common tool in almost all types of aviation and feature many useful capabilities such as the ability to display traffic, weather, and aviation charts. Despite their potential benefits, while some pilots choose to use EFBs in their flight operations, others continue to rely on traditional paper charts and reference materials. Determination of which factors explain differences in pilot acceptance and adoption of EFBs could influence …

Enhanced Coupling Strength Gratings For Outcouplers In Optical Waveguides, Ruo-Hua He

Electrical Engineering Theses and Dissertations

Gratings used for silicon photonic waveguides were demonstrated with outcoupling efficiency greater than 60% in a short grating length of 13 µm at a wavelength of 1550 nm. Due to problems of generating light from silicon, light has to be generated by either growing III-V material, wafer bonding III-V material to silicon, or externally generated light has to be coupled into and out of silicon photonic waveguides. Gratings have been used in semiconductor lasers to obtain single frequency operation. Some applications such as telecommunications require a narrow and single spectral line. And such single frequency lasers are typically distributed Bragg …

Measuring And Evaluating Safety Maturity Of Construction Contractors: Multicriteria Decision-Making Approach, Ali A. Karakhan, Sathyanarayanan Rajendran, John Gambatese, Chukwuma Nnaji

All Faculty Scholarship for the College of the Sciences

Evaluating the safety maturity of construction contractors before awarding the contract is an effective strategy that many owners have started to implement. Given the importance of workplace safety, awarding the contract to safer contractors can enhance project performance outcomes in terms of safety, quality, cost, and schedule. Safety maturity is one quality of a construction organization encompassing interdependent factors that can be used to evaluate expected safety performance. However, there is no formal decision-making framework available in literature that owners can use to evaluate contractor safety maturity. The present study aims to bridge this gap in safety knowledge by proposing …

Atomic Diffusion In The Feal Alloy: A Research Via The Kinetic Monte Carlo Method, E V Manrique Castillo, F A. Reyes Navarro

Journal of Metals, Materials and Minerals

For a binary alloy with an ordered structure B2, we research the atomic migration by means of kinetic Monte Carlo simulations, where the atomic migration results from the exchange of positions between an atom and a vacancy in a rigid lattice. The atomistic kinetic model we used is based on the jump rate theory and the residence time algorithm, wherein we consider the pair interactions between neighbours up to the next-nearest neighbours. Likewise, we determine the ratio of the diffusion coefficients as a function of temperature and investigate the antiphase boundary mobility in the last stages of the ordering process. …

Synthesis Of Nanoparticulate Ti-Doped Zno By Solution Combustion Technique, O Jongprateep, P Deedit, R Puranasamriddhi, K Meesombad

Journal of Metals, Materials and Minerals

ZnO and TiO2 have been widely accepted as prominent photocatalysts. Enhancement of their photocatalytic activities can be achieved through particle refinement and doping. Solution combustion technique is a simple and cost-effective method capable of producing fine ceramic powders with homogeneous chemical compositions. It is, therefore, employed in this research project as the technique to synthesize nanometer-sized Ti-doped ZnO powders. The research also aimed at examining a relationship among doping contents, chemical composition, particle sizes, and photocatalytic performance of the synthesized powder. Compositional analysis revealed that the solubility limit of Ti in zinc oxide was within the range of 3 at% …

Multiuser Coding And Signal Processing In A Low Power Sensor Network, Dongqi Lai

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

Backscatter communication system is a wireless communication system that is used by both academic community and industry circles in recent years. This communication system only requires ultra-low power usage and simple design of the sensors. This project is using backscatter communication system to transmit data with backscatter tags. The method we used is semi-passive backscatter communication. This project focuses on transmitting signals with multiple sensors so there is a problem about distinguishing the signal reflected by different nodes. We modulated the transmitting digital signal with Walsh function to solve the problem of separating the signals between different nodes. By using …

Implementation Of Vision Processing Tasks On A Smart Camera Platform Using Neighborhood Processors, Dingyi Hong

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

Two applications of vision processing on a smart camera platform using neighborhood processors are presented. A smart camera application of real-time trajectory calculation for tracking objects and predicting their path of motion by using a single intelligent camera or a dual camera system are designed, simulated and implemented. Another application of object recognition with a key points algorithm for detecting simple shaped objects and locating the camera position within a 3-D coordinate system via imaging by using artificial neural network is applied to provide quick and accurate processing on a neighborhood-level parallel processor or other limited vision chip. For all …

Employees Attitudes Toward Safety Risk Management And Safety Performance At U.S. Airports, Umut Oztekin

Theses and Dissertations

Increasing air transportation traffic around the world initiated authorities to take new safety measures into consideration. In 2010, the Federal Aviation Administration (FAA) issued a Notice of Proposed Rulemaking to introduce Safety Management Systems (SMS) to the airport community (FAA, 2016). Throughout the years, the FAA has introduced SMS as a 4-pillar system for airports to provide a systematic approach to identify hazards, mitigate risks, increase safety performance, enhance reporting systems, and increase communication systems. It is advised by the FAA that airport employees should confidently speak up and report safety related incidents for further development of airport safety. The …

Integrated Scheduling And Control In Discrete-Time With Dynamic Parameters And Constraints, Logan Beal, Damon Petersen, David R. Grimsman, Sean Warnick, John Hedengren

Faculty Publications

Integrated scheduling and control (SC) seeks to unify the objectives of the various layers of optimization in manufacturing. This work investigates combining scheduling and control using a nonlinear discrete-time formulation, utilizing the full nonlinear process model throughout the entire horizon. This discrete-time form lends itself to optimization with time-dependent constraints and costs. An approach to combined SC is presented, along with sample pseudo-binary variable functions to ease the computational burden of this approach. An initialization strategy using feedback linearization, nonlinear model predictive control, and continuous-time scheduling optimization is presented. The formulation is applied with a generic continuous stirred tank reactor …

Total Hemispherical Apparent Radiative Properties Of The Infinite V-Groove With Diffuse Reflection, Rydge B. Mulford, Nathan S. Collins, Michael S. Farnsworth, Matthew R. Jones, Brian D. Iverson

Faculty Publications

Dynamic control of radiative surface properties enables optimization of thermal management systems for spacecraft, radiative cooling systems and other applications [1-3]. Various methods of altering the absorption or emission from a surface have been investigated [4-6]. Use of origami-inspired, tessellated surfaces to control apparent radiative surface properties is a promising technology [7-9]. Realizing the full potential of tessellated surfaces to dynamically control apparent radiative surface properties requires convenient methods of calculating apparent properties as a function of tessellation geometry and intrinsic radiative surface properties. This paper focuses on the use of geometry to affect total, hemispherical properties of V-grooves comprised …

Surgical And Medical Applications Of Drones: A Comprehensive Review, James C. Rosser, Vudatha Vignesh, Brent A. Terwilliger, Brett C. Parker

Publications

Background: Drones have the ability to gather real time data cost effectively, to deliver payloads and have initiated the rapid evolution of many industrial, commercial, and recreational applications. Unfortunately, there has been a slower expansion in the field of medicine. This article provides a comprehensive review of current and future drone applications in medicine, in hopes of empowering and inspiring more aggressive investigation. Database: A literature search was performed by EBSCO (Elton B. Stephens Company) Discovery Service, searching the phrases "drones," "UAV," "unmanned aerial vehicles," "UAS," and "unmanned aerial systems." A second search was used to identify sources that contained …

Surgical And Medical Applications Of Drones: A Comprehensive Review, Brent Terwilliger, James C. Rosser Jr., Vudatha Vignesh, Brett C. Parker

Publications

Drones have the ability to gather real time data cost effectively, to deliver payloads and have initiated the rapid evolution of many industrial, commercial, and recreational applications. Unfortunately, there has been a slower expansion in the field of medicine. This article provides a comprehensive review of current and future drone applications in medicine, in hopes of empowering and inspiring more aggressive investigation.

Towards Domain-Specific Modeling Methodology For Avionic Safety-Critical Systems, Emanuel S. Grant

Computer Science Faculty Publications

The use of domain-specific modeling languages and associated methodologies, provide support in application domain where the safe and reliable operations of the systems are of paramount importance to the users and organizations, and wherein the domains are well understood and documented. One such area of domain-specific modeling application is in the field of avionic systems. For software systems to be used onboard aircrafts they must be certified, and as such certification protocols have been established for developing these safety-critical systems. These established protocols are usually represented as textual documents and inherently are difficult to apply directly in software development environments. …