Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

University of Nevada, Las Vegas

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 4621 - 4650 of 5885

Full-Text Articles in Entire DC Network

Hydrostratigraphy And Allostratigraphy Of The Cenozoic Alluvium In The Northwestern Part Of Las Vegas Valley, Clark County, Nevada, David Joseph Donovan Jan 2005

Hydrostratigraphy And Allostratigraphy Of The Cenozoic Alluvium In The Northwestern Part Of Las Vegas Valley, Clark County, Nevada, David Joseph Donovan

UNLV Retrospective Theses & Dissertations

This investigation was conducted to determine the location, nature, and boundaries of the most permeable unit within the alluvial aquifer material in Las Vegas Valley. It was prompted by declines in specific capacity of about 90% at the Las Vegas Valley Water District's West Central Well Field. It was hypothesized that the decline in specific capacity resulted from dewatering of the most permeable interval of the alluvium. Lithologic descriptions from wells and aquifer test information were analyzed for geologic and hydrogeologic variability. New information, in the form of detailed unpublished lithologic and hydrologic information, was available from twenty water wells …

Go to article

Development Of A Dynamic Spatial Data Analysis System For Transportation, Mukunda Rao Dangeti Jan 2005

Development Of A Dynamic Spatial Data Analysis System For Transportation, Mukunda Rao Dangeti

UNLV Retrospective Theses & Dissertations

Transportation systems are complex entities that are owned and operated by a diverse group of organizations. The management of such systems requires substantial amounts of data to be monitored, acquired, managed, analyzed, maintained and modeled. Due to the spatial and temporal nature of such data, Geographic Information Systems (GIS) and Global Positioning Systems (GPS) technologies offer significant promise to help with such activities. The focus of this dissertation is to develop a GIS based decision support system to help manage transportation systems. The purpose of the study is to develop a system, which compiles, pre-processes, and manages various transportation system …

Go to article

Confidence Intervals For The Ratio Of Poisson Parameters, Libo Zhou Jan 2005

Confidence Intervals For The Ratio Of Poisson Parameters, Libo Zhou

UNLV Retrospective Theses & Dissertations

Let k1, k2 be non-negative integers with k1 + k 2 ≥ 2; let X1, X 2,.. Xk1 ;Y1, Y2,.. Yk2 be mutually independent Poisson random variables with parameters lambda 1,lambda2,.. lk1 ; mu1, mu2,.. mk2 , respectively. In this article, we consider constructing confidence intervals for ratio of Poisson parameters q=l1˙l2 ˙l3&cdots;lk1 m1˙m2˙m 3&cdots;mk2 . For the ratio of two Poisson parameters q=l1m1 , an exact formula for confidence interval is given. A numerical method to obtain confidence interval for q=l1˙l2 ˙l3&cdots;lk1 m1˙m2˙m 3&cdots;mk2 is developed. Examples are given for each of the two cases.

Go to article

Sequential Procedure For Test Of Uniformity In Multinomial Models, Hai Zhen Jan 2005

Sequential Procedure For Test Of Uniformity In Multinomial Models, Hai Zhen

UNLV Retrospective Theses & Dissertations

In this thesis we deal with a sequential procedure for testing uniformity in a given multinomial distribution using inverse sampling. From a decision theoretic point of view, we devise an efficient stopping rule that satisfies a pre-determined P*-condition. Dirichlet distribution Type II will be primarily used for developing the inverse-type sequential procedure based on the decision theoretic point of view. We assume a non-zero cell probability (parameter) for given multinomial models. In particular, we will be focusing on the equal cell probability configuration (EPC) among all feasible cell configurations. One of the main goals is to find optimal sample sizes …

Go to article

Confidence Interval Estimation For A Geometric Distribution, Majgan Beria Jan 2005

Confidence Interval Estimation For A Geometric Distribution, Majgan Beria

UNLV Retrospective Theses & Dissertations

A geometric random variable models the number of trials required to obtain the fist success in a Bernoulli process. This distribution has been used by Merrill (2005) as a probability model for the distribution of drivers yielding to pedestrians in a traffic microsimulation investigation. The sample proportion of yielding drivers was calculated using the method of moments, and the bootstrap method was used for computing a confidence interval (CI) for the success probability. The properties of this CI for the geometric distribution, however, have not been investigated. The main objective of this thesis is to develop the performance of the …

Go to article

Analyzing Association Rules Produced By Applying The Apriori Algorithm To Structured Data, Darshana Gala Jan 2005

Analyzing Association Rules Produced By Applying The Apriori Algorithm To Structured Data, Darshana Gala

UNLV Retrospective Theses & Dissertations

In this thesis, we will use various techniques from data mining to draw interesting results from a set of structured data on personal privacy information. In particular, the well-known, Apriori Algorithm will be used to find frequent item sets and association rules in this data. This process has been shown to be effective in predicting the presence of one type of data when other data is present in other data mining applications; The thesis will also include a detailed analysis of rules generated by the algorithm and their natural interpretations.

Go to article

Evaluating Hydraulic Conductivity Of Desert Soils At The Amargosa Desert Research Site Near Beatty, Nevada, Jon Woodrow Wilson Jan 2005

Evaluating Hydraulic Conductivity Of Desert Soils At The Amargosa Desert Research Site Near Beatty, Nevada, Jon Woodrow Wilson

UNLV Retrospective Theses & Dissertations

This study tested predictive equations of unsaturated hydraulic conductivity. Quarterly measurements of water-content measured over 12 years were collected from six sites at the Amargosa Desert Research Site (ADRS) located within northern Amargosa Desert, Nevada. ADRS Soils consist of unconsolidated to weakly indurated deposits of early Pliocene and Quaternary age alluvial-fans; fluvial and freshwater deposits; Descriptive statistics and soil properties provide input for method evaluation. Methods include those by Green and Corey (1971), and van Genuchten (1980). Resulting graphical comparisons, for both methods, suggests a good and poor correlation in trench and native devegetated sites, respectively. Conductivity values differing by …

Go to article

Training Professionals' Impressions And Opinions About Their Role In Hospitality, Valentini Kalargyrou Jan 2005

Training Professionals' Impressions And Opinions About Their Role In Hospitality, Valentini Kalargyrou

UNLV Retrospective Theses & Dissertations

Billions of dollars are spent yearly on employee training. Thus, extensive research has been done on why training is important to the advancement of organizations. However, little research has been done on the actual providers and facilitators of the training and development. This research is designed to identify the feelings, insights, emotions, expectations, and beliefs of the training professionals about their role in hospitality. A qualitative research, Zaltman's Metaphor Elicitation Technique (ZMET) was performed with ten training professionals from two hotels in Las Vegas, Nevada. Study results indicated (1) the importance of their role within the organization, (2) the high …

Go to article

Bayesian Estimation Of The Normal Mean In The Presence Of Non-Detects, Ahmed Khago Jan 2005

Bayesian Estimation Of The Normal Mean In The Presence Of Non-Detects, Ahmed Khago

UNLV Retrospective Theses & Dissertations

This paper is concerned with the Bayesian approach to estimate the mean when encountered with left-censored data sets. Considering the joint non-informative prior, we derived the posterior probability density function of the mean of left-censored data. However, this density function is not recognizable and we can not analytically integrate it to obtain the normalizing constant. In other words, we can not compute analytically the posterior pdf or posterior moments. Numerical integration involving the adaptive Simpson quadrature rule was used in Mat-lab to obtain the posterior mean and the upper credible limit (UCL). Several numerical examples are given which illustrate the …

Go to article

Process Analysis And Simulation Of Solar Thermochemical Hydrogen Generation, Mohammad Arif Khan Jan 2005

Process Analysis And Simulation Of Solar Thermochemical Hydrogen Generation, Mohammad Arif Khan

UNLV Retrospective Theses & Dissertations

In this study three different kind of solar thermochemical cycles (methane reforming process, sulfur-iodine cycle and copper-chlorine cycle) have been analyzed to produce hydrogen gas. Methane reforming processes (steam methane reforming, partial oxidation and autothermal reforming) have been analyzed and simulation flowsheets have been developed. In this analysis, the temperature of all the reforming reactors are varied in the range of 500-1000 °C due to the transient nature of the solar energy. The results show that the POX reforming system is better than the other two systems for the production of the same amount of hydrogen from CH4; Process analysis …

Go to article

Synthesizing A Piccolo Using Physical Modeling Techniques, Pamela Pnina Mandelbaum Jan 2005

Synthesizing A Piccolo Using Physical Modeling Techniques, Pamela Pnina Mandelbaum

UNLV Retrospective Theses & Dissertations

Physical modeling is a very affective technique used to simulate a musical instrument. It is different than most synthesizing techniques, because the synthesized sound is completely computer generated. It works by starting with a pure frequency and then applying a physical model to this signal. The physical model is created by analyzing the effects that the real instrument would have on a pure signal and then designing a model to simulate these effects using signal processing techniques; The piccolo is an instrument similar to the flute. Music synthesizers will use synthesized flute sounds for music that requires a synthesized piccolo. …

Go to article

Vissim Model Development Of A Mid-Block Pedestrian Crossing Between Signalized Intersections, John Christopher Merrill Jan 2005

Vissim Model Development Of A Mid-Block Pedestrian Crossing Between Signalized Intersections, John Christopher Merrill

UNLV Retrospective Theses & Dissertations

Pedestrian mid-block crossings through arterial roadways have significant impacts on vehicular level of service and safety. Past research has been conducted to simulate these crossings. However, a practical, realistic model and methodology have not been established for analysis and planning of mid-block pedestrian crossings. The objective of this study was to create a practical traffic microsimulation methodology for mid-block pedestrian crossings through a case study using a versatile transportation software package. VISSIM v3.70 was selected because of its ability to model individual vehicle and pedestrian interactions. The developed methodology provided a framework for model development at any pedestrian mid-block crossing …

Go to article

Handwritten Number Recognition, Meenakshisundaram Murugan Jan 2005

Handwritten Number Recognition, Meenakshisundaram Murugan

UNLV Retrospective Theses & Dissertations

The main focus of this research is to automate medical form processing. An important step in this process is separating handwriting from printed text characters. We developed a filtering technique that extracts handwritten text from the printed text in the form. Once the handwritten text is segregated, each line of the segregated text is identified. The identification step is followed by character segmentation. Statistical analysis is performed on the gaps between the characters in each line. This results in a binormal curve clearly depicting two regions indicating if the gap represents the spacing between characters within a word or between …

Go to article

Conjugacy Numbers For Cyclic Groups Of Even Order, Tanya Jessica Murray Jan 2005

Conjugacy Numbers For Cyclic Groups Of Even Order, Tanya Jessica Murray

UNLV Retrospective Theses & Dissertations

Let Gamma be a finite group, let X be a subset of Gamma where X-1 = X and 1 ∉ X. The conjugacy graph Con(Gamma; X) has vertex set Gamma and two vertices g, h ∈ Gamma are adjacent if and only if there exists x ∈ X with g = xhx-1. Let O be a group with generating set Delta. The conjugacy number con(O; Delta) is defined as the minimum integer k ≥ 2 for which there exists a nonabelian group Gamma of order k|O| and a subset X of Gamma such that Cay(O; Delta) is isomorphic to a …

Go to article

Joint Design For Shock Mitigation, Gopi Nallani Jan 2005

Joint Design For Shock Mitigation, Gopi Nallani

UNLV Retrospective Theses & Dissertations

Smart projectiles carry various electronic components that can be damaged by severe shock loads. Propagation of shock from the region of initial loading to the locations of critical components can result in their failure. The objective of the research is to mitigate (absorb/reflect/disrupt, etc.) the incident shock loading, including simulating set-back, set-forward and balloting loads on a projectile as it exits the gun muzzle and predicting the structural response of internal electronic components. A detailed finite element analysis of the projectile and internal components is presented. The effect of electronic component mounting location on peak acceleration and RMS acceleration has …

Go to article

Policy Analysis: Evaluating Theories Of The Hermeneutic Critique, Cecilea Mun Jan 2005

Policy Analysis: Evaluating Theories Of The Hermeneutic Critique, Cecilea Mun

UNLV Retrospective Theses & Dissertations

This thesis evaluates three theories representing the three perspectives identified by Goktug Morcol as perspectives of the hermeneutic critique in policy analysis, while explicating the revolutionary process that the science is currently undergoing. The evaluation is focused around the question as to whether the three theories are viable alternatives to positivist theories. First, a brief history of policy analysis is presented, highlighting the conditions that contributed to the rise of the general positivist paradigm as the ideal in policy analysis. This is followed by a summary and criticisms of the general positivist paradigm. Next, summaries of Dvora Yanow's interpretive theory, …

Go to article

Virtual Design And Modeling Of Various Manufacturing Processes For Remote Fabrication Of Transmuter Fuel, Jamil Mohamad Renno Jan 2005

Virtual Design And Modeling Of Various Manufacturing Processes For Remote Fabrication Of Transmuter Fuel, Jamil Mohamad Renno

UNLV Retrospective Theses & Dissertations

As currently envisioned, over 70,000 tons of high-level nuclear waste would be stored inside the planned Yucca Mountain repository. After emplacement, the site must be maintained and guarded for over 10,000 years; The reprocessing of spent nuclear fuel is a possible alternative to geological storage. Here, depleted Uranium would be separated from Plutonium and Minor Actinides. While Plutonium can be 'burned' in commercial nuclear reactors, the minor actinides would be transmuted into other elements. The large-scale deployment of remote fabrication and refabrication processes (approx. 100 tons of Minor Actinides (MA) annually) will be required. Process automation has the potential to …

Go to article

Homeland Security Emergency Response Wind Field Plume Flow, Lynn Bryant Nielson Jan 2005

Homeland Security Emergency Response Wind Field Plume Flow, Lynn Bryant Nielson

UNLV Retrospective Theses & Dissertations

Numerous atmospheric dispersion models for emergency response exist. The Office of the Federal Coordinator for Meteorological Services is leading the development of new atmospheric dispersion models for emergency response. Collaborative efforts, mutual aid agreements, and partnerships synergize forming meteorological data networks providing atmospheric modeling for enhancing emergency response. Technological advances in computer meteorological forecasts are producing data used for predicting wind field plume flow for potential emergency response; Fire stations make excellent sites for meteorological towers because they are located in fire response districts distributed throughout a community and the meteorological data gathered may serve multiple purposes; A tower was …

Go to article

Pectoral Fin Control Of A Biorobotic Auv In The Dive Plane, Aditya Simha Jan 2005

Pectoral Fin Control Of A Biorobotic Auv In The Dive Plane, Aditya Simha

UNLV Retrospective Theses & Dissertations

Maneuvering of biologically inspired robotic undersea vehicles (BAUVs) is considered in the dive plane using pectoral-like oscillating fins. Firstly, an open-loop and optimal feedback control system is designed to control a biorobotic AUV in the dive pLane Next, an inverse control system for dive-plane control is derived based on a discrete-time AUV model. An approximate minimum phase system with a new output variable is derived for the purpose of design; Computational fluid dynamics (CFD) is used to parameterize the forces generated by a mechanical oscillatory flapping foil, which attempts to mimic the pectoral fin of a fish. Finally, a control …

Go to article

A Problem Concerning The Existence Of Graphs With Certain Degrees, Jonathan Seary Summer Jan 2005

A Problem Concerning The Existence Of Graphs With Certain Degrees, Jonathan Seary Summer

UNLV Retrospective Theses & Dissertations

Let n ≥ 2 be a positive integer. For a sequence ( S0, S1, S 2,..Sn-1) of nonnegative integers we study the problem of whether there exists a graph there exists a graph containing i=0n-1Si vertices having exactly Si vertices whose degrees are congruent to i modulo n for each i = 0, 1, 2,.., n-1. When such a graph does exist, the sequence (S0, S 1, S2,..Sn -1) is said to be realizable. It is known for modulo 2, 3, and 4 that such a sequence is realizable with seventeen exceptions for modulo 3 and twenty-four exceptions for modulo …

Go to article

Reject Inference Methodology Skewed Missing Data Problem, Atsuko Watanabe Jan 2005

Reject Inference Methodology Skewed Missing Data Problem, Atsuko Watanabe

UNLV Retrospective Theses & Dissertations

Statistical models are most predictive and robust when the historical data used to build the model covers sufficient representation from the population. A financial organization uses a scoring model, developed with historical data, to determine if a consumer should be granted a line of credit for which they apply. When the existing model is too old or the applicant population has changed, a new model is to be developed, but the range of historical data, essential to the predictive model development, does not include the entire applicant population because of the declines. A technique called reject inference is typically used …

Go to article

Improvements To Patient-Specific Skeletal Dosimetry, Jeffrey Scott Wyler Jan 2005

Improvements To Patient-Specific Skeletal Dosimetry, Jeffrey Scott Wyler

UNLV Retrospective Theses & Dissertations

Nuclear medicine encompasses numerous steps, with accuracy being a key component throughout. Exactitude in skeletal dosimetry is of importance due to the high radiosensitivity of the hematopoietic cells populating the marrow cavities within trabecular bone. In fact, active marrow is generally the dose limiting organ in both radioimmunotherapy and bone pain palliation; Current research involving improvements in skeletal dosimetry is being pursued through nuclear magnetic resonance- (NMR) and computed tomography- (CT) imaging. Images acquired from these imaging modalities are coupled to Monte Carlo transport models to calculate S values for radionuclides localized within the skeleton. This is accomplished by in-vivo …

Go to article

Feasibility For The Use Of Non-Contact Ultrasound For Application With Asphalt Concrete Materials, Michael Robert Dunning Jan 2005

Feasibility For The Use Of Non-Contact Ultrasound For Application With Asphalt Concrete Materials, Michael Robert Dunning

UNLV Retrospective Theses & Dissertations

The quality control of the production of asphalt concrete and the subsequent placement for roadway pavement requires the extensive use of laboratory and field-testing. These tests determine mix properties such as gradation, binder content, air void content, and percent compaction. The amount of time it takes to perform these tests generates time delays in the information transfer from the laboratory to the construction and plant inspectors. The lack of timeliness of a test result may result in placement of an inferior product being placed. Thus, there would be a great benefit for the application of a rapid test method during …

Go to article

Science Education For Girls: A Partnership Between Girl Scouts And Nasa, Anne Grisham Jan 2005

Science Education For Girls: A Partnership Between Girl Scouts And Nasa, Anne Grisham

UNLV Retrospective Theses & Dissertations

This study investigated the evolution of the relationship between NASA and the Girl Scouts of the USA (GSUSA). The stories of three groups of key players; NASA, Girl Scout National Staff, and Girl Scout volunteers explained the scope and depth of this unique partnership. Common goals between GSUSA and NASA of encouraging girls to seek careers in science, technology, engineering, and math (STEM) were studied to determine if the goals were met as a result of this collaboration. Outcomes such as the Memorandum of Understanding, numbers of attendees at workshops, and artifact reviews aided in the collection of data; The …

Go to article

Factors That Impact The Instructional And Technical Support Provided By Site-Based Technology Coordinators In K--12 Schools, Douglas B Hearrington Jan 2005

Factors That Impact The Instructional And Technical Support Provided By Site-Based Technology Coordinators In K--12 Schools, Douglas B Hearrington

UNLV Retrospective Theses & Dissertations

School districts are increasingly employing teachers as site-based coordinators to support and facilitate a myriad of information and communication technology (ICT) related innovations. This study describes the barriers and enabling conditions influencing the technical and instructional support, and staff development provided by these coordinators. Diffusion theory (Rogers, 2003) and a staff development model developed by Guskey and Sparks (2000) were used as frameworks for this study of 134 coordinators from a large school district; The findings of this study indicate that staff development and instructional support fell well below desired levels, and timely technical support is increasingly difficult to provide. …

Go to article

The Influence Of Self-Efficacy And Working Memory Capacity On Problem Solving Efficiency, Bobby H Hoffman Jan 2005

The Influence Of Self-Efficacy And Working Memory Capacity On Problem Solving Efficiency, Bobby H Hoffman

UNLV Retrospective Theses & Dissertations

The study investigated the influence of self-efficacy beliefs, working memory capacity and problem complexity on problem solving performance, response time, and problem solving efficiency. Previous research investigated these factors from an absolute performance perspective, but not from the perspective of efficiency, defined as the ratio of problem-solving accuracy over time; Students completed an operational span working memory task, rated their self-efficacy for solving multiplication problems without the use of paper or calculation aids, and then solved computer-based cognitive multiplication problems, under conditions of varying complexity. Two competing hypotheses were proposed, which state that the efficiency of problem solving is either …

Go to article

A Modified Bootstrap Method For Handling Non Detects In Environmental Data, Michelle Melissa Guillaume Jan 2005

A Modified Bootstrap Method For Handling Non Detects In Environmental Data, Michelle Melissa Guillaume

UNLV Retrospective Theses & Dissertations

Many samples taken for environmental purposes have concentrations that are measured below the detection limit. Below the detection limit does not mean that there is no concentration present; there may be a concentration present that cannot be accurately measured by the analytical instrument or cannot be determined with 95% confidence that the concentration is greater than zero (EPA, 1989). These concentrations are defined non-detects in the data. When the concentration of the contaminant of concern in a sample falls below the detection limit, it is standard laboratory procedure to represent these data as

Go to article

An Investigation Of The Kaplan-Meier Upper Confidence Limit For The Population Mean From Environmental Samples With Nondetects, Violeta Graciela Hennessey Jan 2005

An Investigation Of The Kaplan-Meier Upper Confidence Limit For The Population Mean From Environmental Samples With Nondetects, Violeta Graciela Hennessey

UNLV Retrospective Theses & Dissertations

The Kaplan-Meier (K-M) estimator is a non-parametric estimator of the survival function, used in lifetesting and medical follow-up studies where some of the observations are incomplete (right-censored data). In environmental applications, the user is faced with the problem of contaminant concentration falling below the limit of detection (DL) of the instrument (left-censored data). The K-M estimator has recently been proposed in environmental literature for computing the Upper Confidence Limit (UCL) of the mean in the presence of nondetects in environmental data sets. The properties of this UCL, however, have not been investigated. In this thesis, I propose to use Monte …

Go to article

On Using Block Principal Component Analysis For Reducing Gene-Expression Data Dimensions, Sang Hee Lee Jan 2005

On Using Block Principal Component Analysis For Reducing Gene-Expression Data Dimensions, Sang Hee Lee

UNLV Retrospective Theses & Dissertations

Since a microarray gene expression database contains a large number of variables and a relatively small number of samples, using and analyzing the databases require an intense, large-dimension computation method. Principal component analysis (PCA) is a useful tool to reduce the number of dimensions, and therefore, the complexity. PCA allows us to analyze the gene expression database with a relatively small data dimension without losing relevant information and increases the analytic visibility of the data. The initial computation using PCA, however, involves calculating a high-dimension covariance or correlation matrix and requires time and hardware resources which are limited in most …

Go to article

Semi-Active Control Techniques For Shock Isolation, Ganesh B Maganti Jan 2005

Semi-Active Control Techniques For Shock Isolation, Ganesh B Maganti

UNLV Retrospective Theses & Dissertations

In this thesis the problem of control of semi-active devices (MR damper, MR elastomer) for shock isolation systems are considered. Semi-active control systems combine the best features of both the passive and active control systems, offering the reliability of passive devices, yet maintaining the versatility and adaptability of fully active devices. First the question of stability and control of a two degree-of-freedom magnetorheological (MR) fluid damper shock isolation system is considered. It is shown that for any arbitrarily time varying input current, the system is absolutely stable. This explains the shock isolation capability of the MR damper system even with …

Go to article

First Prev Next Last