Engineering Commons^™

From Linear To Nonlinear Control Means: A Practical Progression, Zhiqiang Gao

Electrical and Computer Engineering Faculty Publications

With the rapid advance of digital control hardware, it is time to take the simple but effective proportional-integral-derivative (PID) control technology to the next level of performance and robustness. For this purpose, a nonlinear PID and active disturbance rejection framework are introduced in this paper. It complements the existing theory in that (1) it actively and systematically explores the use of nonlinear control mechanisms for better performance, even for linear plants; (2) it represents a control strategy that is rather independent of mathematical models of the plants, thus achieving inherent robustness and reducing design complexity. Stability analysis, as well as …

The Effect Of Model Formulation On The Comparative Performance Of Artificial Neural Networks And Regression, Michael F. Cochrane

Engineering Management & Systems Engineering Theses & Dissertations

Multiple linear regression techniques have been traditionally used to construct predictive statistical models, relating one or more independent variables (inputs) to a dependent variable (output). Artificial neural networks can also be constructed and trained to learn these complex relationships, and have been shown to perform at least as well as linear regression on the same data sets. Research on the use of neural network models as alternatives to multivariate linear regression has focused predominantly on the effects of sample size, noise, and input vector size on the comparative performance of these two modeling techniques. However, research has also shown that …

A New Approach For Weighted Constraint Satisfaction, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

We consider the Weighted Constraint Satisfaction Problem which is an important problem in Artificial Intelligence. Given a set of variables, their domains and a set of constraints between variables, our goal is to obtain an assignment of the variables to domain values such that the weighted sum of satisfied constraints is maximized. In this paper, we present a new approach based on randomized rounding of semidefinite programming relaxation. Besides having provable worst-case bounds for domain sizes 2 and 3, our algorithm is simple and efficient in practice, and produces better solutions than some other polynomial-time algorithms such as greedy and …

Improvements In Wavelength Modulation Spectroscopy Using Ratios Of Higher Harmonics, James Michael Barrington

Electrical & Computer Engineering Theses & Dissertations

Experiments in Wavelength Modulation Spectroscopy have been conducted at Old Dominion University since 1996. The method provides a highly sensitive, nonintrusive method of probing gases. Research has concentrated on effectively modeling the higher harmonic shapes that are measured experimentally. Accurately modeling these signals will result in the ability to reliably extract the information contained in transition line shapes.

In order to accurately depict the signals, the theory must be thoroughly understood. This thesis develops the theory of Wavelength Modulation Spectroscopy from two aspects: a direct Fourier series expansion of a time varying intensity profile and through communication theory. In addition, …

Human Factors Survey Of Aviation Maintenance Technical Manuals, Alex Chaparro, Loren S. Groff

Publications

The reported work is part of a 3 phased effort to identify human factors issues in the development of aviation technical manuals, and make recommendations for the improvement of those documents. Phase 1 of this research effort surveyed the procedures used by five manufacturers to develop maintenance documentation. Several human factors issues were identified in the development process employed by these manufacturers. They included the reactive rather than proactive use of user evaluations, the limited use of user input and procedure validation, no systematic attempts to track error, and the lack of standards for measuring document quality. Given the issues …

The Development Of An Enterprise Supply Chain Model For Naval Warship Construction, Rex A. Wallen

Computational Modeling & Simulation Engineering Theses & Dissertations

The utilization of computer simulation in the shipbuilding industry is not a new concept and many shipyards in the US and around the world are using simulation tools in a variety of ways with various levels of success. In other industries, computer simulation has proven itself as a powerful tool for reducing non-value added activities and promises to become more prominent in its use as a resource management tool. Its use in the manufacturing of outfitting components in the construction of Naval warships has had limited success due mainly to the inherent nature of ship construction, especially shipyards engaged in …

Embedded Software Programming To Develop A Command Line User Interface For Monitoring And Debugging A Manually Driven Gas Regulator Control System, Syed N. Hyder

Electrical & Computer Engineering Theses & Dissertations

This thesis presents a complete embedded programming model and software codes for a command-line user interface for CONCOA's gas regulator control system. Control Corporation of America (CONCOA) manufactures high-pressure gas regulators, which mechanically control the pressure at their outlets. Since the control system is based on mechanical regulators, adding or stopping gas flow from the system can cause manifold fluctuation that could further cause the pressure to rise or fall with time. The main motivation for developing a command line user interface is to provide a centralized computer control to monitor and debug the gas regulator control system electronically by …

Systematic Methods For The Design Of A Class Of Fuzzy Logic Controllers, Saad Y. Yasin

Dissertations

Fuzzy logic control, a relatively new branch of control, can be used effectively whenever conventional control techniques become inapplicable or impractical. Various attempts have been made to create a generalized fuzzy control system and to formulate an analytically based fuzzy control law. In this study, two methods, the left and right parameterization method and the normalized spline-base membership function method, were utilized for formulating analytical fuzzy control laws in important practical control applications. The first model was used to design an idle speed controller, while the second was used to control an inverted control problem. The results of both showed …

An Assessment Of Air Force Development Portfolio Management Practices, Michael A. Greiner, Kevin J. Dooley, Dan L. Shunk, Ross T. Mcnutt

Faculty Publications

Selecting and managing development project portfolios is a critical function within the Air Force’s weapon systems development process. Decision makers must weigh benefits, costs, and mission needs for a variety of proposed new initiatives and current weapon systems programs in order to develop an effective portfolio that provides the best value to the User. This research examines current Air Force development portfolio management practices as perceived by those involved with the decision making process. Research findings indicate several gaps between Air Force practices and those commercial best practices as found in the literature. A general approach for bridging the differences …

Ethylene Oxide And Propylene Oxide Random Copolymer/Sodium Chloride Aqueous Two-Phase Systems: Wetting And Adsorption On Dodecyl-Agarose And Polystyrene, Yingqing Huang, Daniel Forciniti

Chemical and Biochemical Engineering Faculty Research & Creative Works

Liquid/liquid partition chromatography is a mild yet powerful separation method for a variety of biological materials. This work demonstrates that it should be feasible to immobilize an ethylene oxide-propylene oxide (EO/PO) random copolymer solution and to use a solution of NaCl equilibrated against the polymer solution as the mobile-phase (poly (EO-PO) [P(EO-PO)] and NaCl form two aqueous phases known as aqueous two-phase systems). Three random copolymers with different molecular weights and EO/PO ratios were used. Dodecyl-agarose and polystyrene were tested as possible supports. The wetting energies of the aqueous two-phase systems on these two kinds of surfaces were calculated as …

Trends. Nuclear Power Plants And Homeland Security And Defense: The Views Of Representative Markey, Ibpp Editor

International Bulletin of Political Psychology

The author discusses US Representative Edward J. Markey, and his public discourse about the "safety and security of the nuclear power industry.

Biometrics And The Bottom Line For Aviation Security, Ibpp Editor

International Bulletin of Political Psychology

This article attempts to identify the utility of biometric technology for variants of aviation security.

Yucca Mountain Ventilation Studies Support And Associated Code Enhancements, George Danko

Publications (YM)

The Task 20 project was prematurely closed by DOE on the basis of becoming critical data to the Yucca Mountain project. Task 20 indeed delivered the first, published hydrothermal-ventilation model, MULTIFLUX V1.0 and V1.1 to BSC during 2001 to support the AMR Rev01 report. The numerical model is designed to predict temperature and humidity distributions in and around the emplacement drifts and on the waste packages stored in a ventilated, high-level nuclear waste repository.

Issues In Modeling Military Space, Peter F. Olsen

Theses and Dissertations

Fighter Pilots students undertake an intense 120-day training program. New classes of students enter the training program at regular interval. Students endured rigorous academic, simulator, and aircraft training throughout the program. Squadron schedulers ensure the multiple classes and students are scheduled for the activities. Simulator and aircraft training are scheduled individual for each student. Academic training are taught to the class. Aircraft utilization must also be considered. Aircraft Sortie training are also constrained by daylight hours. Additionally, students are limited to a maximum of three training events in a given day. Squadron schedulers must balance these requirements to ensure students …

Effects Of Shot-Peening On High Cycle Fretting Fatigue Behavior Of Ti-6al-4v, Halil I. Yuksel

Theses and Dissertations

Effects of Shot-peening on High Cycle Fretting Fatigue behavior of Ti-6Al-4V were investigated. Experiments were performed with 6.35 mm thick specimens which provided S/N curves. After the tests, it was observed that the specimens failed near the trailing edge of contact. Scanning Electron Microscopy showed that cracks initiated on the contact surface for 6.35 mm, and at the depth of specimen ranging from 200 to 300 microns for 3.81 mm thick specimens. Initial crack orientation was around 37 and 42 degrees respectively for 6.35 and 3.81 mm thicknesses. Finite Element Analysis (FEA) was conducted, and using FEA results, Smith-Watson-Topper, Findley, …

Design Study Of Triggered Isomer Heat Exchanger-Combustion Hybrid Jet Engine For High Altitude Flight, Christopher E. Hamilton

Theses and Dissertations

This study investigated the possibility of utilizing a Triggered Isomer Heat Exchanger (TIHE) within a conventional jet engine in order to increase the endurance of a High Altitude Long Endurance (HALE) Intelligence, Surveillance, and Reconnaissance (ISR) aircraft. Optimizations of the conventional and TIHE engines along with selection of a switchover flight condition, where the aircraft switches from combustion to TIHE operations, were made utilizing engine design and mission analysis software. Radiation shield weights were determined utilizing point source gamma ray shielding methods. The jet engine best suited for the hybrid use, where both combustion and TIHE components located in a …

Fabrication Techniques For Iii-V Micro-Opto-Electro-Mechanical Systems, Jeremy A. Raley

Theses and Dissertations

This thesis studies selective etching techniques for the development of Al_xGa_1-xAs micro-opto-electro-mechanical systems (MOEMS). New MEMS technology based on materials such as Al_xGa_1-xAs enables the development of micro-systems with embedded active micro-optical devices. Tunable micro-lasers and optical switching based on MOEMS technology will improve future wavelength division multiplexing (WDM) systems. WDM vastly increases the speed of military communications and sensor data processing. From my designs, structures are prepared by molecular beam epitaxy. I design a mask set for studies of crystal plane selectivity. I perform a series of experiments on the selective …

University Of Nevada, Las Vegas Advanced Accelerator Applications University Participation Program: Quarterly Report Fourth Quarter (December 2001 To February 2002), Anthony Hechanova

Transmutation Research Program Reports (TRP)

This Quarterly Report is a primary deliverable from the University of Nevada, Las Vegas (UNLV) Advanced Accelerator Applications (AAA) University Participation Program (UPP) Director to the U.S. Department of Energy (DOE) as described in the UNLV AAA proposal and Statement of Work for the Fourth Quarter.

The UNLV AAA UPP Director implements the program’s administration using staff from the Harry Reid Center for Environmental Studies (HRC) to ensure that work conducted under the UNLV AAA UPP meets program objectives. The UNLV AAA program consists of three components: Program Support, Research Infrastructure Augmentation, and Student Research.

Thermal Analysis Of Fly Ashes Sourced From European Non-Blended Coals, Kenneth T. Stanton, Mark R. Towler, Patrick Mooney, Robert G. Hill, Xavier Querol

Chemical and Biochemical Engineering Faculty Research & Creative Works

Fly ashes exist as a mixture of major amorphous phases and minor crystalline phases. For commercial applications, such as in concretes and for the production of zeolites, it would be desirable to be able to predict the reactivity of fly ashes. The amorphous phase dominates degradation behaviour, because glasses have a higher potential energy than the equivalent crystal structure and the variation of bond angles and distances in a glass make the bond breakage easier. Despite the large quantities of fly ash produced annually by coal-burning power plants, there have been very few studies investigating the microstructure and composition of …

Environment-Induced Degradation And Crack-Growth Studies Of Candidate Target Materials: Aaa Task-4 Quarterly (December 1, 2001 – February 28, 2002) Report, Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The primary objective of this task is to evaluate the effect of hydrogen on environment-assisted cracking of candidate materials for applications in spallation-neutron-target (SNT) systems such as accelerator production of tritium (APT) and accelerator transmutation of waste (ATW). The materials selected for evaluation and characterization are martensitic stainless steels including HT- 9, EP 823 and 422. The susceptibility to stress corrosion cracking (SCC) and hydrogen embrittlement (HE) of these alloys will be evaluated in environments of interest using tensile specimens under constant load and slow-strain-rate (SSR) conditions. The extent and morphology of cracking of these alloys will further be evaluated …

Development Of A Mechanistic Understanding Of High-Temperature Deformation Of Alloy Ep-823: Aaa Task-10 Quarterly (12/1, 2001 –02/28, 2002) Report, Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The objective of this task is to evaluate the elevated temperature tensile properties of Alloy EP-823, a leading target material for accelerator-driven waste transmutation applications. The test material will be thermally treated prior to evaluation of its tensile properties at temperatures relevant to the transmutation applications. The deformation characteristics of tensile specimens, upon completion of testing, will be evaluated by surface analytical techniques including scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The overall results are expected to provide a mechanistic understanding of high-temperature deformation behavior of Alloy EP-823 as a function of heat treatment.

Highlights of Accomplishment

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Remote Resonant-Circuit Analyte Sensing Apparatus With Sensing Structure And Associated Method Of Sensing, Craig A. Grimes

Chemical and Materials Engineering Faculty Patents

A resonant sensing apparatus for operative arrangement within a test environment to sense an analyte. A sensing structure is included having an antenna in electrical communication with a resonant circuit and a structural element made of a material that selectively responds to the analyte. This sensing structure will resonate at a particular characteristic resonant frequency in the presence of an applied interrogation electromagnetic field and the analyte upon the occurrence of the selective response. A receiver is used for remotely identifying a value for the characteristic resonant frequency by measuring a plurality of values for electromagnetic emission intensity of the …

Method For Preparing Porous Shells Or Gels From Glass Particles, D. E. Day, Samuel D. Conzone

Materials Science and Engineering Faculty Research & Creative Works

A method is provided for preparing shells, concentric shells or porous, homogenous gels from alkali borate glass particles at low temperatures (i.e. room temperature or less than above 100° C.). The alkali borate glass particles contain one or more cations such as aluminum which react with an aqueous solution containing an anion such as hydroxide to form an aqueous insoluble material having a solubility limit of less than about 0.01 wt. percent. TTie resulting shells or gels may be used in many different applications such as a filler in resins, as filters, precursors for nano-sized powders, as thin surface films …

Thin Film Interference Filters For 25ghz Channel Spacing, M. A. Scobey, R. M. Fortenberry, L. F. Stokes, W. P. Kastanis, Dennis J. Derickson

Electrical Engineering

No abstract provided.

Evaluation And Analysis Of Array Antennas For Passive Coherent Location (Pcl) Systems, Baris Calikoglu

Theses and Dissertations

Passive Coherent Location (PCL) systems use a special form of a radar receiver that exploits the ambient radiation in the environment to detect and track targets. Typical transmissions of opportunity that might be exploited include television and FM radiobroadcasts. PCL implies the use of a non-radar electromagnetic sources of illumination, such as commercial radio or television broadcasts also referred as transmitters of opportunity. The use of such illumination sources means that the receiver needs to process waveforms that are not designed for radar purposes. As a consequence, the receivers for PCL systems must be much more customized than traditional receivers, …

Calibration And Validation Of A Regional Climate Model For Pan-Arctic Hydrologic Simulation, Helin Wei, William J. Gutowski Jr., Charles J. Vörösmarty, Balazs M. Fekete

Advanced Science Research Center

A number of polar datasets have recently been released involving in situ measurements, satellite retrievals, and reanalysis output that provide new opportunities to evaluate regional climate in the Arctic. These data have been used to assess a 1-yr pan-Arctic simulation (October 1985–September 1986) performed by a version of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) that incorporated the NCAR land surface model (LSM) and a simple thermodynamic sea ice model to investigate interactions between the land surface and atmosphere. The model’s standard cloud scheme using relative humidity was replaced by one using simulated cloud …

Histologic Evaluation Of The Efficacy Of Rhbmp-2 Compared With Autograft Bone In Sheep Spinal Anterior Interbody Fusion, Harvinder Sandhu, Jeffrey M. Toth, Ashish Diwan, H. B. Seim Iii, Linda E.A. Kanim, J. Michael Kabo, A. Simon Turner

Biomedical Engineering Faculty Research and Publications

Study Design. The sheep anterior lumbar spinal fusion model was used to study the efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2)–collagen composite in comparison with autograft to enhance spinal interbody fusion. Comparisons were drawn from temporal radiographic and end-point biomechanical and histologic data.

Objective. To analyze histologically the ability of rhBMP-2 to achieve complete arthrodesis between vertebral bodies.

Summary of Background Data. Studies using rhBMP for enhancement of anterior interbody fusion have used numerous endpoints. However, systematic histologic evaluation of the fusion has not been conducted.

Methods. Twelve sheep underwent single-level anterior lumbar interbody fusion performed with a cylindrical …

The Effect Of The Thermal Barrier Coating On The Displacement Instability In Thermal Barrier Systems, Anette M. Karlsson, T. Xu, A. G. Evans

Mechanical Engineering Faculty Publications

Thermal barrier systems are susceptible to instability of the thermally grown oxide (TGO) at the interface between the bond coat and the thermal barrier coating (TBC). The instabilities have been linked to thermal cycling and initial geometrical imperfections, as well as to misfit strains due to both oxide growth and thermal expansion misfit. Numerical simulations are used to investigate the role of the thermo-mechanical properties of the TBC in this instability. It is found that the TBC constrains the deformation, whereupon instabilities develop preferentially in regions where crack-like imperfections either pre-exist in the TBC or are created because of the …

Analysis Of Ultra Wide Band (Uwb) Technology For An Indoor Geolocation And Physiological Monitoring System, Cengiz Alabacak

Theses and Dissertations

The goal of this research is to analyze the utility of UWB for indoor geolocation and to evaluate a prototype system, which will send information detailing a person’s position and physiological status to a command center. In a real world environment, geolocation and physiological status information needs to be sent to a command and control center that may be located several miles away from the operational environment. This research analyzes and characterizes the UWB signal in the various operational environments associated with indoor geolocation. Additionally, "typical usage scenarios" for the interaction between UWB and other devices are also tested and …

Genetic Routing Algorithms To Optimize Availability In Broadband Wireless Networks With Load Balancing, William S. Hortos

Electrical Engineering and Computer Science Faculty Publications

Packet-switched networks using the Internet Protocol (IP) provide multimedia services through broadband wireless access to mobile and fixed subscribers from an IP core network via bi-directional paths consisting of a hierarchy of high-speed routers, switches, and servers. Packets are aggregated at the nodes that form the ordered links of end-to-end paths between subscriber and gateway. Network resources are allocated at nodes to meet quality of service (QoS) requirements of new and existing calls. If sufficient resources are not available to satisfy a call's QoS, the call is blocked or dropped, reducing network "uptime" or availability. Packet flows are shared among …