Engineering Commons^™

Towards A General Description Of Translation-Invariant And Translation-Covariant Linear Transformations: A Natural Justification Of Fourier Transforms And Fuzzy Transforms, Irina Perfilieva, Vladik Kreinovich

Departmental Technical Reports (CS)

In many practical situations, we are interested in the dependencies that do not change with time, i.e., that do not change when we change the origin of the time axis. The corresponding translation-invariant transformations are easy to describe: they correspond to convolutions, or, equivalently, to fuzzy transforms.

It turns out that if we relax the invariance condition and require only that the transformation be translation-covariant (i.e., that it appropriately changes under translation), we get exactly two classes of transformations: Fourier transforms and fuzzy transforms. This result explain why both transforms have been successfully used in data processing.

Pwisegen: Generating Test Cases For Pairwise Testing Using Genetic Algorithms, Pedro Flores, Yoonsik Cheon

Departmental Technical Reports (CS)

Pairwise testing is a combinatorial testing technique that tests all possible pairs of input values. Although, finding a smallest set of test cases for pairwise testing is NP-complete, pairwise testing is regarded as a reasonable cost-benefit compromise among combinatorial testing methods. In this paper we formulate the problem of finding a pairwise test set as a search problem and apply a genetic algorithm to solve it. We also describe an open-source tool called PWiseGen for generating pairwise test sets. According to our experiments, PWiseGen produces competitive results compared with existing pairwise testing tools. Besides, it provides a framework and a …

Towards Optimal Few-Parametric Representation Of Spatial Variation: Geometric Approach And Environmental Applications, Misha Kosheleva, Octavio Lerma, Craig Tweedie

Departmental Technical Reports (CS)

In this paper, we use geometric approach to showthat under reasonable assumption, the spatialvariability of a field f(x), i.e., the expectedvalue F(z)=E[(f(x+z)-f(x))²], has the formF(z)=|Σ g_ij*z_i*z_j|^α.We explain how to find g_ij and αfrom the observations, and how to optimally place sensorsin view of this spatial variability.

Measures Of Deviation (And Dependence) For Heavy-Tailed Distributions And Heir Estimation Under Interval And Fuzzy Uncertainty, Nitaya Buntao, Vladik Kreinovich

Departmental Technical Reports (CS)

Traditionally, in science and engineering, most statistical techniques are based on the assumption that the random variables are normally distributed. For such distributions, a natural characteristic of the "average" value is the mean, and a natural characteristic of the deviation from the average is the variance. However, in many practical situations, e.g., in economics and finance, we encounter probability distributions for which the variance is infinite; such distributions are called heavy-tailed. For such distributions, we describe which characteristics can be used to describe the average and the deviation from the average, and how to estimate these characteristics under interval …

Strategies To Improve And Preserve Flexible Pavements At Intersections, Imad N. Abdallah

Open Access Theses & Dissertations

Many rural intersections originally constructed with thin untreated flexible base and hot mix or a two-course surface treatment experience severe pushing, shoving and rutting. These failures cause an extremely rough surface that can cause damage to small vehicles and potentially cause motorists to lose control of their vehicle. These distresses almost always result in complete failure of the existing pavement that must be repaired several times during the life of the roadway by maintenance forces. Pavement sections constructed with the same materials adjacent to the intersection perform adequately until the approach (approximately 150 ft in advance) of the intersection and …

Electrochemical Behavior Of Zinc, Carlos E. Castillo

Open Access Theses & Dissertations

The investigation focused on the corrosion of galvanized steel exposed to soil. The primary objective of the study was to develop a technique for monitoring the corrosion behavior of samples in the field by measuring the potential and current with respect to time (or electrochemical noise). Electrochemical electrodes were designed to simulate the galvanized steel in contact with thin electrolytes which are usually generated in soils as they collect and drain rain water depending on soil porosity.

The corrosion behavior of the galvanized steel was also studied by using electrochemical impedance spectroscopy (EIS) coupled with potentiokinetic scans to predict the …

Implications Of Surface Runoff Recharge In Semi-Arid Regions On Groundwater Sustainability, Omar M. Al-Qudah

Open Access Theses & Dissertations

Amargosa Desert, Nevada regional groundwater studies show that the surface runoff infiltration occurring in the arroyos following runoff producing storms, and this infiltration is considered to be a major source of groundwater recharge. Groundwater infiltration through alluvium was investigated in the Amargosa Desert using borehole drill cuttings, groundwater chemistry, and applying a novel method for collecting runoff water. The sampling process included sediment, precipitation, and runoff water. In total, 176 runoff, 182 sediment, and 45 precipitation samples were collected between January, 2009 and January, 2011.Water chemistry, chloride concentrations, and stable isotopes of water collected from specially designed runoff samplers, placed …

Spatio-Temporal Cardiac Pacing Sites Localization And Time Varying Pericardium Potential Maps Projection Using Ecg Precordial Leads And A Single Moving Dipole Model, Jaime R. De La Cruz

Open Access Theses & Dissertations

A novel non-invasive method for the spatiotemporal localization of the sites of strongest cardiac activity, and for the creation of time varying Pericardium Potential Maps (PPM), with the use of patients' ECG precordial leads, is proposed in this Thesis study. Compared to previous studies, which analyze electrocardiograms in either time domain or spatial domain, the proposed method has the advantage of a simultaneous spatiotemporal electrocardiograph analysis and a 3-D visualization of pericardium potentials maps, as well as, the pericardium surface polarization patterns during the cardiac cycle. The spatial properties added to the electrocardiogram allow for the analysis of specific regions …

Assessment And Evaluation Of Peripheral Neuropathy From Diabetic Mellitus Using Systems Analysis Approach, Oscar Alonso Espino

Open Access Theses & Dissertations

Currently in America 1 out of every 10 residents suffers from diabetes, and this tendency is likely to grow up to "1 of every 3" by the year [6]. Diabetes exhibits several complications. In 2005, the lead cause of stroke and heart disease was diabetes, 68% of the cases [1]. In 2008, 44% of kidney failure was associated with diabetes [1]. 60 to 70 % of cases of diabetes have a mild to severe nervous system damage [1]. Diabetic patients who have developed peripheral neuropathy tend to also develop foot ulceration. In an advanced stage a foot ulcer can lead …

Experimental Study Of Thermoelectric Properties For Randomly Distributed Carbon Nanotubes And Silicon Carbide Nanoparticles, Onasis Garcia

Open Access Theses & Dissertations

In this experimental study, the thermoelectric (TE) properties of carbon nanotubes (CNTs) and Silicon carbide (SiC) nanoparticles have been investigated. Nanoparticles were randomly disrtibuted on a non-conductive glass or quartz substrate. The carbon nanotubes used were single-walled and multi-walled type, consisting of approximately 60% semiconducting 40% metallic tubes. The experimental design is analogous to that of a thermocouple measurement, with the nanoparticle layers creating hot and cold joints with a dissimilar metal Alumel (Ni-Al). Voltage (mV), current (μA) and resistance (Ω) values were measured with respect to temperature (°C), and Seeback coefficient values were also calculated in parallel. Summarized results …

Enterprise Transformation Through A Zachman-Bayesian Framework To Improve Efficiency & Productivity, Ramakanth Gona

Open Access Theses & Dissertations

Although organizations are aware of the benefits of enterprise architectures models, organizations have difficulties determining deficiencies in their business architecture. Organizational assessment tools often do not achieve expectations as sold to management. Performance measures often fail to properly represent necessary holistic measurements. Methods for capturing deficiencies in current business models and deterring improvements to optimize business processes are rare. This thesis develops a new experimental architecture modeling approach for enterprise transformations. The approach is efficient in capturing deficiencies and finding correlations which can become targeted goals for improvements. The Zachman enterprise architecture framework provides a holistic view of organizational models …

Preparation And Characterization Of Iron Oxide And Hydroxide Based Nanomaterials, Guillermo Carbajal Franco

Open Access Theses & Dissertations

Iron (Fe) oxides and hydroxides are common and abundant materials. They exhibit diverse crystal structures, properties and phenomena by virtue of which they find a wide range of scientific and technological applications. Controlled growth and manipulation of the specific structure and electronic behavior to meet the requirements of a given application is a challenging problem in view of many possible phases and composition of the resulting materials. The preparation method and experimental conditions will, therefore, significantly affect the properties and performance of Fe oxides and hydroxides. The goal of the project is to obtain Fe-based oxide/hydroxide catalytic materials and to …

Modeling Impulse Oscillometry Data: Using Augmented-Ric And Extended-Ric Respiratory Impedance Model Paramaters To Track Pulmonary Health And Disease, Carlos Domingo Ramos Rocha

Open Access Theses & Dissertations

Respiratory diseases are a great health concern. Early detection of disease could greatly improve quality of life and yet the most common pulmonary function test can be an unreliable diagnostic method, especially in the case of children. A reliable method of detecting and assessing small airway impairment could greatly help with timely diagnosis. This research approaches this problem by taking Impulse Oscillometry (IOS) data and its model-derived parameters and assessing their utility in tracking respiratory function and more specifically, small airway function.

This research first describes the use of electric circuits as models to describe lung properties at distinct regions …

Psychophysical Similarity Based Feature Selection For Nodule Retrieval In Ct, Ravi K. Samala

Open Access Theses & Dissertations

The emerging paradigms in cancer research indicate the need for a multi-perspective and multi-modal screening approach for early lung cancer diagnosis to increase the probability of clinical resection. Currently no standalone screening methodology is proved to suffice for a clinical diagnosis. Computed tomography has been proved to present abnormality at an early stage with less impact on survival rate in population studies. Nevertheless, because of its non-invasive characteristic, it can be used for diagnosis, prognosis and visualization of tumor. Studies have shown that Computer aided diagnosis (CAD) as a second reader can perform in a similar capacity as a radiologist. …

Impulse Oscillometric Features And Parsimonious Respiratory Models Track Small Airway Function In Hispanic And Anglo Children, Erika Guadalupe Meraz Tena

Open Access Theses & Dissertations

Asthma is an inflammatory condition of the peripheral (small) airways resulting in airway hyper-reactivity and, among other symptoms, airflow obstruction. It is the most prevalent chronic respiratory disease in children. Reliable and patient-friendly instruments and methods are required to help pulmonologists accurately detect asthma and Small Airway Impairment (SAI) with acceptable clinical accuracy, specificity and sensitivity. Impulse Oscillometry System (IOS) based on the Forced Oscillation Technique (FOT) has been successfully used to measure lung function in children with a high degree of sensitivity and specificity to SAI and Asthma. IOS is a patient-friendly lung function to measure the mechanical impedance …

An Investigation Into The Effect Of Blood Glucose Level Changes On Lf/Hf Parameter Of Hrv Signal In Non-Diabetic And Diabetic Individuals, Reza M. Amanipour

Open Access Theses & Dissertations

The analysis of time duration between consecutive R waves of electrocardiogram (ECG) is a standard method to evaluate the variations in heart rate. The physiological literature reveals that blood glucose levels modulate the autonomic nervous system (ANS) activity and heart rate variability (HRV) is representative of the cardiovascular autonomic function. In the research, an investigation was carried out to investigate the relationship between HRV signal measures derived from ECG and arterial blood glucose changes in five non-diabetic and five diabetic individuals during normoglycemic and mildly hyperglycemic conditions. A CleveLabs BioCapture wireless device was used to acquire ECG signals from ten …

Separation Of Humic Matter From Groundwater Via Anion Exchange Resin: Comparison Of Bead And Powder Form, Sandra June Everett

Open Access Theses & Dissertations

This work describes a comparison of a bead and powder form of anion exchange resin for removing humic matter from groundwater. The materials and procedures described herein involve a manufactured dry humic matter and two forms of the same anion exchange resin. Spectroscopy was the chosen procedure for analysis of organics.

Preliminary experiments were required to gain a better understanding of the materials and to prepare the best conditions for actual experimental research. Five concentrations of humic acid were used for experimental purposes at 0.5, 1, 5, 10 and 20 mg/L. Three concentrations of resin were used: 500, 750 and …

Development Of A New Evolutionary Algorithm Based On Adaptive Echolocation Applied To A Multi Objective Version Of The Redundancy Allocation Problem, Karla Rocio Gutierrez

Open Access Theses & Dissertations

The intention of this research is to develop a new algorithm that it is mainly focus in the principle of echolocation or also called biosonar. This principle is active in many animals such as: birds, shrews, dolphins and bats, these last ones are going to be a fundamental part of our study. These animals use it as radar in order to find food, obstacles or just to locate objects.

These animals use ultrasound beams with a certain degree of angle and multiple receivers; such as the two ears that are located slightly apart, so at the time of the returning …

Solving The Partial Differential Equation Of Vibrations With Interval Parameters Using The Interval Finite Difference Method, Brenda G. Medina

Open Access Theses & Dissertations

Accuracy and efficiency are among the main factors that drive today's innovative disciplines. As technology rapidly advances, efficiency takes on new meanings but what about accuracy? How accurate is accurate? Human error, uncertainties in measurement, and rounding errors are just some causes of inaccuracy. Interval Computations is an area that allows for such issues to be taken into account; for each measurement attained (for example), an interval can be built by considering the error associated with the measurement, and such an interval can be utilized in the mathematical computations of interest.

We consider the partial differential equation (PDE) of vibrations …

Evaluation Methods For Health Monitoring Of Aerospace Structure Rotary Joints, Sergio Armando Navarro

Open Access Theses & Dissertations

In September 2007, the excessive vibrations played a significant role in the station operation since one of the rotary joints, which provides the station electrical energy, presented an anomaly. The replacement of its bearing components and re-lubrication were necessary to reduce the problem. To avoid a new anomaly, the inspection of the rotary joints performance continues by using the accelerometers data. This thesis presents three new approaches to monitor the vibrations at the International Space Station based on Root-Mean-Square, kurtosis, and Approximate Entropy (ApEn). MATLAB functions and codes were necessary to implement the three monitoring techniques results from the provided …

Aerosol Characterizaton In El Paso-Juarez Airshed Using Optical Methods, Angel E. Esparza

Open Access Theses & Dissertations

The assessment and characterization of atmospheric aerosols and their optical properties are of great significance for several applications such as air pollution studies, atmospheric visibility, remote sensing of the atmosphere, and impacts on climate change. Decades ago, the interest in atmospheric aerosols was primarily for visibility impairment problems; however, recently interest has intensified with efforts to quantify the optical properties of aerosols, especially because of the uncertainties surrounding the role of aerosols in climate change. The main objective of the optical characterization of aerosols is to understand their properties. These properties are determined by the aerosols' chemical composition, size, shape …

Development Of A Heat Transfer Test Rig For Finding Heat Transfer Characteristics Of Liquid Methane, Sergio Flores

Open Access Theses & Dissertations

Most large scale rocket engines use a regeneratively cooled system to cool the rocket engine using either the rocket fuel or oxidizer. The use of liquid methane as a rocket fuel is an emerging technology proving to have several advantages over current rocket fuels. However, liquid methane is lacking the extensive research as a rocket fuel compared to highly used rocket fuels like liquid hydrogen. A heat transfer test rig was built with the goal to characterize the heat transfer characteristics of liquid methane as it passes through a heated channel. The development of the test rig underwent considerations designed …

Evaluation And Recommendation Of Mix Design For Emulsion Stabilized Bases, Samuel Franco

Open Access Theses & Dissertations

Asphalt emulsion has been used for base material stabilization in a few TxDOT districts. Results from these practices were quite different. The initial performance of two projects on US287 constructed around 2000 in the Amarillo District has been found to be satisfactory. However, the Yoakum District has reported problems with asphalt emulsion for base work in a project on FM 237. The preliminary conclusion from these trials has been that asphalt emulsion may not perform well in the high humidity/high rainfall areas like east Texas. On the other hand, using calcium-based additives to stabilize base courses in road construction has …

On Feasibility Of Reducing Metal Fuel Content And Operating Temperatures In Chemical Oxygen Generators, Allen Garcia

Open Access Theses & Dissertations

Chemical oxygen generators are widely used in aircraft, submarines, spacecraft, and other applications, problems such as combustion instabilities and a risk of fire may be present. For example, due to malfunction of an oxygen generator, fire occurred onboard the Mir Space Station in 1997. It is thus important to improve the process stability and fire safety of chemical oxygen generators. Chemical compositions for oxygen generators include an oxygen source such as sodium chlorate (NaClO3), a transition metal oxide as a catalyst, and a metal fuel to provide energy for self-sustaining combustion. Eliminating or decreasing the metal fuel would decrease the …

Fundamental Studies Of Co-Base Superalloy Biomedical Prototypes Fabricated By Electron Beam Melting: Microstructures And Microstructural Architecture, Sara M. Gaytan

Open Access Theses & Dissertations

Rapid prototyping, especially electron beam melting (EBM) technology by ARCAM have proven to provide outstanding microstructural and mechanical properties on different alloys fabricated by this technology. Being a computer designed driven technology, complex components, that are hard or even impossible to fabricate by traditional manufacturing techniques, can be fabricated by layer-by-layer EBM technology.

Microstructural and mechanical properties are compared for an EBM femoral knee component prototype with a traditionally-fabricated and body-removed femoral knee implant. Block and cylindrical shape components fabricated by EBM were also analyzed for this project. The alloy utilized for these components is Co-26Cr-6Mo-0.2C characterized by the standards …

Variation Of Number And Mass Concentration Of Particulate Matter At The International Bridge Of The Americas In El Paso, Texas, Veronica Guerrero

Open Access Theses & Dissertations

Particle mass and number concentration measurements during different seasonal periods were conducted to study the effects caused by both privately own vehicles (POV) and commercial operated vehicles at the International Bridge of the Americas (BOTA), El Paso, Texas. There were two monitoring sites: UTEP air quality mobile monitoring site at the El Paso Water Utility (EPWU) located at the Chamizal National Memorial Park (CNMP) near the bridge. At this location measurements of traffic counts, size distribution, particle number and mass concentration PM"₁₀" (EP"₁₀"; El Paso PM"₁₀") and PM"_2.5" (EP"_2.5"; El …

Study Of Probabilistic Approach For Structural Health Assessment Of Aerospace Structures, Jose Antonio Garcia

Open Access Theses & Dissertations

Current practical approaches used in structural health assessment programs of aerospace structures involve performing a fracture mechanics analysis to verify the safe life of structural components. The analysis typically makes several conservative assumptions implemented by NASA fracture control standard practices for critical structural components. This well-established paradigm for fracture control follows a deterministic approach and, in some cases, the calculations may produce overly conservative remaining life estimates.

This thesis describes the results of a study to approach the health assessment challenge of several critical components using probabilistic methods. The probabilistic analysis takes the current deterministic model and identifies variables that …

Investigation On Flame Characteristics Of Oxy-Fuel Combustion, Md R. Islam

Open Access Theses & Dissertations

Oxy-fuel combustion is currently being considered by the U.S Department of Energy as a promising technology for efficient carbon capture. This technology could substantially reduce NOx and CO2 emissions. In addition, the implementation of oxy-fuel combustion technology in a power generation system could potentially reduce negative environmental impacts of fossil fuel use. It also encourages the use of reliable and domestic energy sources. The U.S. Department of Energy has made efforts to investigate the performance of a CO2 and H2O diluted oxy-fuel combustion system in a high-pressure combustor. In an effort to better understand and characterize the fundamental flame characteristics …

Photocatalytic Destruction Of Halogenated Organic Compounds In Water With A New Photocatalyst, Mabruka Hadidan

Open Access Theses & Dissertations

In this research, a newly developed high surface area semiconductor porous material was synthesized from potassium titanium niobium mixed oxide (KTiNbO5) to be used as a photo catalyst in the presence of UV light to degrade halogenated organic compounds in water. The goal of the project was to investigate the catalytic activity of the material for its effectiveness in the degradation of the halogenated organic compounds, and it is the first investigation of this new photocatalyst with halogenated compounds. Model compounds dichloromethane, 1-chlorobutane, chlorobenzene, and trifluoroacetic acid in aqueous solutions were tested with the photocatalyst under ultraviolet light irradiation, using …

Fractal-Cosysmo Systems Engineering Cost Estimation For Complex Projects, Manish Shivram Khadtare

Open Access Theses & Dissertations

Cost estimation for engineering projects has advanced beyond the bottom-up counting of costs and the top-down use of analogies. Parametric cost estimation is now employed to estimate volatile software costs, as well as the cost of Systems Engineering (SE) effort in engineering projects. The Constructive Systems Engineering Cost Model (COSYSMO) estimates the number of Person-Months (PM) necessary to complete systems engineering projects by using project size and cost parameters. On re-examining the nature of systems engineering and the structures of complex projects that must be built in an orderly fashion on a variety of scales, it is apparent that a …