Engineering Commons^™

Experimental Investigation Of The Influence Of Molecular Weight On Mixing And Penetration In Supersonic Dissimilar Gaseous Injection Into A Supersonic Cross-Flow, Troy A. Giese

Theses and Dissertations

In pursuit of a more efficient and effective fuel-air mixing for a SCRAMjet combustor, this study investigated relative near field effects of molecular weight on mixing and penetration of different gaseous injection into a supersonic (M=2.9) cross flow. Helium and argon gas were chosen as injectants because of the large differences in molecular weights. Also, mixing enhancement was observed by injecting the traverse gas jet parallel to the compression face of a ramp. Color schlieren photography was used to identify the shock structures and interactions in the flow field. Measurements of mean flow properties were used to establish the jet …

Effects Of Near-Field Scatterers On Space-Time Adaptive Processing, Jonathan W. Fitton

Theses and Dissertations

Near-field scatterers, such as the wing of an airplane, can affect the ability of the processor to null out clutter and jammer signals. The target, clutter, and jammer signals will reflect off the near-field scatterers into the array and appear to be coming from a direction different from their true sources. This thesis develops a theoretical model for the direct path and scattered path signals from the target, clutter, and jamming signals. The optimum weight vector, normally computed using the steering vector to the target and the covariance matrix of the undesired signals, must now include the effects of the …

Secondary Data Support And Non-Homogeneities In Space-Time Adaptive Processing, Todd B. Hale

Theses and Dissertations

One of the primary problems with the application of Space-Time Adaptive Processing (STAP) techniques is secondary data support for the interference plus noise covariance matrix estimate. Reed has shown the required secondary data support to achieve performance within 3 dB of optimal SINR is approximately equal to twice the degrees of freedom (DOF) used in the algorithm. Reed proved this rule for Sample Matrix Inversion (SMI) techniques. A concern arises when applying this rule to a newer class of reduced dimension STAP algorithms that do not fall under the SMI umbrella. This thesis focuses on the Cross Spectral Metric (CSM) …

A Comparative Analysis Of Networks Of Workstations And Massively Parallel Processors For Signal Processing, David C. Gindhart

Theses and Dissertations

The traditional approach to parallel processing has been to use Massively Parallel Processors (MPPs). An alternative design is commercial-off-the-shelf (COTS) workstations connected to high-speed networks. These networks of workstations (NOWs) typically have faster processors, heterogeneous environments, and most importantly, offer a lower per node cost. This thesis compares the performance of MPPs and NOWs for the two-dimensional fast Fourier transform (2-D FFT). Three original, high-performance, portable 2-D FFTs have been implemented: the vector-radix, row-column and pipeline. The performance of these algorithms was measured on the Intel Paragon, IBM SP2 and the AFIT NOW, which consists of 6 Sun Ultra workstations …

Optimal Orbit Insertion Strategies Using Combined High And Low Thrust Propulsion Systems, Darren W. Johnson

Theses and Dissertations

Low thrust electric propulsion systems are becoming sufficiently mature to consider their use as primary propulsion for orbital transfer in place of high thrust chemical systems. Instead of facing an either/or situation, it may be advantageous to use both types. This effort demonstrates a technique for finding orbital transfer strategies that use both high and low thrust propulsion systems and which result in optimal tradeoffs of the performance parameters cost of orbit insertion, total orbit transfer time, and available spacecraft mass at final orbit. These performance parameters are calculated as a function of the fraction of orbit transfer from Low …

A Wire Antenna Designed For Space Wave Radiation Over The Earth Using A Genetic Algorithm, Brian S. Sandlin

Theses and Dissertations

A wire antenna is designed for optimal performance at low elevation angles in the presence of a lossy half-space. A simple genetic algorithm (GA) and GENOCOP III software are each integrated with Numerical Electromagnetics Code Version 4.1 (NEC4.1) to optimize a wire antenna geometry for multiple objectives: power gain, azimuthal symmetry, and input impedance. The performance of the two versions of the integrated GA are compared. Several of the resulting antennas are analyzed, and an antenna is proposed for use in a Remote Intrusion Monitoring System (RIMS). Simulations suggest that the proposed antenna, which is well-matched, offers a significant increase …

Adaptive Critic Designs, Danil V. Prokhorov, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

We discuss a variety of adaptive critic designs (ACDs) for neurocontrol. These are suitable for learning in noisy, nonlinear, and nonstationary environments. They have common roots as generalizations of dynamic programming for neural reinforcement learning approaches. Our discussion of these origins leads to an explanation of three design families: heuristic dynamic programming, dual heuristic programming, and globalized dual heuristic programming (GDHP). The main emphasis is on DHP and GDHP as advanced ACDs. We suggest two new modifications of the original GDHP design that are currently the only working implementations of GDHP. They promise to be useful for many engineering applications …

An Optimization Technique Of Airlines' Seat Inventory Management, Husam Abdallah Mahmoud Fanasheh

Master's Theses - Daytona Beach

This study consisted of a simulation to maximize an airline's Origin- Destination revenues. It has been hypothesized that Linear Programming is capable of maximizing airlines' networks revenues. Simulation was performed with Linear Interactive Discrete Optimizer (LINDO). This project was designed to consider different fares and its classes along with multi flight connections. The seats' allocation process came out with the maximum possible revenues, and enough flexibility in terms of changing such allocation to work around competition and trends. Results came supportive to the hypothesis. Sensitivity analysis provided our model with a tool to modify and change different variables, like fares, …

Introduction To Simulation/Optimization Modeling For Groundwater Containment Remediation And (B) Ramifications Of Applying S/O Modeling To Groundwater Containment Remediation, With Case Study Examples, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Normal use of a simulation model to develop a groundwater extraction/injection strategy employs the following process: (1) specify management goals, (2) assume a pumping strategy, (3) simulate system response to the pumping strategy, (4) evaluate acceptability of the system responses, (5) repeat steps (2-4) as required. This is a trial and error approach that is unlikely to actually yield the best pumping strategy for complicated problems

Optimization Of Torquer Coil Design For Use With The Small Satellite Attitude Control Simulator, David Deloyd Anderson

Undergraduate Honors Capstone Projects

This paper presents a procedure used to optimize the performance of a ferromagnetic core magnetic torquer coil design for use on the Space Dynamics Laboratory (Logan, UT) Small Satellite Attitude Control Simulator. The items of optimization include the primary goal of maximizing the coil 's magnetic moment while reducing power consumption and system mass within given power, mass, and dimensional constraints. The optimization process makes use of several simple equations to determine a few starting points for design, after which an iterative approach based on experimentation is used to produce the final design. It is found that optimal magnetic moment …

Performance Analysis For Genetic Algorithms., Hermrean Wong

Dissertations

Genetic algorithms have been shown effective for solving complex optimization problems such as job scheduling, machine learning, pattern recognition, and assembly planning. Due to the random process involved in genetic algorithms, the analysis of performance characteristics of genetic algorithms is a challenging research topic. Studied in this dissertation are methods to analyze convergence of genetic algorithms and to investigate whether modifications made to genetic algorithms, such as varying the operator rates during the iterative process, improve their performance. Both statistical analysis, which is used for investigation of different modifications to the genetic algorithm, and probability analysis, which is used to …

A Fuzzy Based Load Model For Power System Direct Load Control, K. Bhattacharyya, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Demand side management programs are strategies designed to alter the shape of the load curve. In order to successfully implement such a strategy, customer acceptance of the program is vital. It is thus desirable to design a model for direct load control which may accommodate customer preferences. This paper presents a methodology for optimizing both customer satisfaction and utility unit commitment savings, based on a fuzzy load model for the direct load control of appliances.

Optimization Of Design Parameters For Spines Of Various Geometries, Rong-Hua Yeh

Journal of Marine Science and Technology–Taiwan

This work presents a systematic study on the optimum base diameter, length, heat dissipation, temperature profile, and efficiency of spines by employing fin parameter versus fin efficiency method. The temperature dependent heat transfer coefficient is assumed to be a power-law type. Several common fin geometries including cylindrical, convex parabolic, conical, and concave parabolic profiles are investigated respectively. It is found that the optimum dimensions of spines are functions of fin volume, heat transfer coefficient at fin base, and thermal conductivity. To facilitate the thermal design of heat transfer components, simple mathematical expressions as well as design charts are presented.

Microwave Detection Optimization Of Disbond In Layered Dielectrics With Varying Thickness, Stoyan I. Ganchev, Nasser N. Qaddoumi, Emarit Ranu, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

The detection sensitivity optimization of air disbond in layered dielectric composites, using an open-ended rectangular waveguide, is studied both theoretically and experimentally. The sensitivity of the disbond detection is strongly influenced by the proper choice of parameters such as the operating frequency and the layered composite geometry (conductor backed or terminated by an infinite half-space of air). The capability of optimizing the measurement system parameters to detect and estimate the thickness of a disbonded layer independent of some changes in the thickness of the dielectric coating is also demonstrated. The impact of the parameters influencing detection optimization is theoretically investigated …

Applying Neural Networks To Find The Minimum-Cost Coverage Of A Boolean Function, Pong P. Chu

Electrical and Computer Engineering Faculty Publications

To find a minimal expression of a boolean function includes a step to select the minimum cost cover from a set of implicants. Since the selection process is an NP-complete problem, to find an optimal solution is impractical for large input data size. Neural network approach is used to solve this problem. We first formalize the problem, and then define an ''energy function'' and map it to a modified Hopfield network, which will automatically search for the minima. Simulation of simple examples shows the proposed neural network can obtain good solutions most of the time.

Design Approach For Small Scale Continuous, Steady State Plants, O Kaunde

Tanzania Journal of Engineering and Technology (TJET)

One of the major steps in the design of a process plant is development of an appiopriate flowsheet. At this step, the technical solutions may be con- sidered in relation to the social and economic factors. In this paper, guide- lines for developing a flowsheet for continuous, steady State process in a developing country environment have been proposed. To illustrate the pro- posed guidelines, a case study involving design of an ethanol distillation plant has been used.

Optimum Geometrical Parameters For Prismatic Folded Plate Roofs: System- Atic Search Approach, N Mwitta

Tanzania Journal of Engineering and Technology (TJET)

Folded plate structures have unique structural advantages over conven- nonal beam-and-slab structural forms. Selection of optimum geometrical parameters in design would make folded plate roofs more appealing to the national construction industry in terms ofcost. This paper presents a study on shape optimization of prismatic folded plate roofs for minimum weight of the structure per unit covered area. A computer based systematic search approach has been employed.for the optimization study, while the tranyeer matrix method has been used for analysis. Curves opriinum geometrical parameters versus span have been pre sented for three commonly used shapes of prismatic folded plate roofs. …

Contrast Enhancement Of Medical Images Using Multiscale Edge Representation, Jian Lu, Dennis M. Healy Jr., John B. Weaver

Dartmouth Scholarship

Experience suggests the existence of a connection between the contrast of a gray-scale image and the gradient magnitude of intensity edges in the neighborhood where the contrast is measured. This observation motivates the development of edge-based contrast enhancement techniques. We present a simple and effective method for image contrast enhancement based on the multiscale edge representation of images. The contrast of an image can be enhanced simply by stretching or upscaling the multiscale gradient maxima of the image. This method offers flexibility to selectively enhance features of different sizes and ability to control noise magnification. We present some experimental results …

Automated Manpower Rostering: Techniques And Experience, C. M. Khoong, Hoong Chuin Lau, L. W. Chew

Research Collection School Of Computing and Information Systems

We present ROMAN, a comprehensive, generic manpower rostering toolkit that successfully handles a wide spectrum of work policies found in service organizations. We review the use of various techniques and methodologies in the toolkit that contribute to its robustness and efficiency, and relate experience gained in addressing manpower rostering problems in industry.

Electricity Consumption Patterns In Domestic House Holds, H Kadete

Tanzania Journal of Engineering and Technology (TJET)

Electricity tariff increases from 1988 to 1992 are presented. They are Compared with salaries paid to parastatal workers over the same period. Monthly expenditures on electricity are also presented. Electricity con- sumption profiles have been recorded. The typical end use electrical ap- pliances for each household category have been identified. About 69% of electricity is used for cooking in high demand households. In medium demand households electricity used for lighting dominates ar about 49%. Measurements indicate a 3 peak power consumption profile for domestic dwellings. Voltages of 180V were recorded instead of the expected 230V nominal. Power factor is nor …

Integrated Embedding Optimization Applied To Salt Lake Valley Aquifers, A. Gharbi, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

The embedding optimization modeling approach is adapted to aid sustainable groundwater quantity and quality management of complex nonlinear multilayer aquifers. Implicit block-centered finite difference approximations of the quasi three-dimensional unsteady flow equation and Galerkin finite element approximations of the two-dimensional advection-dispersion transport equation are embedded directly as constraints in the model. Also used are nonlinear constraints describing river-aquifer interflow, evapotranspiration, and vertical flow reduction due to unconfinement. These circumvent use of large numbers of integer variables. The use of both linear and nonlinear formulations in a cyclical manner reduces execution time and improves confidence in solution optimality. The methodology is …

The Computer Aided System For Planning Efficient Routes, J. R. Wright

JTRP Technical Reports

The Indiana Department of Transportation has sponsored the design and implementation of a decision support system for routing highway maintenance vehicles – the Computer Aided System for Planning Efficient Routes (CASPER). Designed for solving multiobjective route design problems, CASPER has been used by agency personnel to design routes for winter maintenance vehicles with significant results: cost savings of more than $9-million to the State of Indiana through more efficient use of materials, equipment, and personnel, while at the same time significant improvement in overall level of network and public service. CASPER integrates 1: an extensive spatial network database (GIS/CAD), 2) …

Introducing Uncertainty Of Aquifer Parameters Into An Optimization Model, Robert L. Ward, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

A stochastic analysis is made for a previously described groundwater contaminant management model {Peralta and Ward, 1988). The stochastic model is based on incorporating uncertainty of the aquifer parameters transmissivity and effective porosity into the model. This is accomplished by finding the partial derivative of drawdown with respect to each of these parameters using a Taylor series expansion approximation of the Theis equation. Input that is required for the stochastic version is the mean of the transmissivity and effective porosity, the coefficient of variation of the transmissivity and effective porosity, and a reliability level (0%-100%) . The reliability is a …

The Application Of Neural Networks To Optimal Robot Trajectory Planning, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

Interpolation of minimum jerk robot joint trajectories through an arbitrary number of knots is realized using a hardwired neural network. Minimum jerk joint trajectories are desirable for their similarity to human joint movements and their amenability to accurate tracking. The resultant trajectories are numerical rather than analytic functions of time. This application formulates the interpolation problem as a constrained quadratic minimization problem over a continuous joint angle domain and a discrete time domain. Time is discretized according to the robot controller rate. The neuron outputs define the joint angles (one neuron for each discrete value of time) and the Lagrange …

Practical Optimization Modeling For Contaminant Plume Management, Richard C. Peralta, Alaa H. Aly

Civil and Environmental Engineering Faculty Publications

Simulation/optimization (S/0) models can be used to greatly speed the process of computing desirable groundwater pumping strategies for plume management. They make the process of computing optimal strategies fairly straightforward and can help minimize the labor and cost of groundwater contaminant clean-up.

Models For The Optimization Of Air Refueling Missions, Clayton H. Pflieger

Theses and Dissertations

This research follows A. Yamani's work on the problem of minimizing total fuel costs for airlift missions that require in-flight refueling. Yamani's major assumptions were removed and the resulting enhanced formulation was applied the the original problem and the related problem of maximizing allowable cabin load. This optimization is accomplished selecting the rendezvous point and initial fuel for each aircraft. The formulation considers a C-141B airlifter refueled once by a KC-135E tanker. Flight is assumed to be at constant altitude and follow great-circle routes. The fuel costs of climb and cruise flight are modeled as functions of gross weight, while …

A Two-Stage Intercontinental Ballistic Missile (Icbm) Design Optimization Study And Life Cycle Cost Analysis, David P. Blanks, Douglas M. Bruce, Anthony M. Logue, Ralph A. Sandfry, Stephen J. Skotte, Michael L. Zywien

Theses and Dissertations

Realities of recent changes in the fiscal environment and the international domestic security structure have caused the strategic community to make some difficult decisions to preserve the capability of the current ICBM force. One of these decisions is to view Minuteman Ill as the centerpiece of the strategic force well into the next century. Extending the life of the 24-year- old Minuteman III system requires system solutions that provide required performance at an affordable life cycle cost. The intent of this study is to demonstrate the feasibility of designing a 2-stage ICBM to perform the Minuteman III mission. The main …

Ground-Water Policy-Making Support: Usem Optimization Modelling Plus Gis And Graphics, Richard C. Peralta, Christopher M. U. Neale, Ali Gharbi, Mazibur Khan, Oscar Daza, Douglas Ramsey, Kurt Vest

Civil and Environmental Engineering Faculty Publications

A support tool for ground-water management decision making involves integration of a multiobjective optimization model, GIS and graphics software. Two results are improved consideration of spatial data within the optimization model and improved conversion of optimal strategies to real-world application. Another result is improved visualization of the trade-offs involved between conflicting management goals.

Comparison Of Optimization Methodologies For Sustained-Yield Groundwater Pumping Planning In East Shore Area, Utah, Shu Takahashi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Combined simulation and optimization models, which are helpful for long-term groundwater planning of complex nonlinear aquifer systems, are developed using alternative modelling approaches. The models incorporate a representation of steady-state, quasi-three-dimensional head response to pumping within an optimization. An embedding model which describes exactly the nonlinear flow of an unconfined aquifer is presented. In contrast with the embedding models presented in the Utah State University Ground Water Model, it directly achieves the optimal solution without a "cycling." To address the nonlinearity of the flow system, response matrix models couple superposition with the cycling procedure. Their linear influence coefficients are generated …

Shape Sensitivity Analysis And Optimization Of Skeletal Structures And Geometrically Nonlinear Solids, Ching-Hung Chuang

Mechanical & Aerospace Engineering Theses & Dissertations

Formulations and computational schemes for shape design sensitivity analysis and optimization have been developed for both skeletal structures and geometrically nonlinear elastic solids. The continuum approach, which is based on the weak variational form of the governing differential equation and the concept of the material derivative, plays a central role in such a development.

In the first part of this work, the eigenvalue and eigenvector sensitivity equations for skeletal structures are derived with respect to configuration variables of joint and support locations. This derivation is done by the domain method as well as the boundary method. The discrete approach for …