Digital Commons Network^™

Long Exposure Point Spread Function Estimation From Solar Adaptive Optics Loop Data, Jose Marino

Dissertations

Adaptive optics (AG) systems provide partial correction to wavefront distortions introduced by the Earth's atmosphere. They have become an essential tool to obtain diffraction-limited observations from ground-based telescopes. However, the AG correction is only partial and post-processing with a good estimate of the point spread function (PSF) is required.

PSF estimates are impossible to measure directly during solar observations due to the lack of point sources in the field-of-view. Moreover, the highly variable day-time seeing conditions require the estimated PSF to be simultaneous with the captured image. A method is presented to estimate the long-exposure PSF of AG-corrected solar observations …

Construction Of Fasr Subsystem Testbed And Application For Solar Burst Trajectories And Rfi Study, Zhiwei Liu

Dissertations

The construction of the Frequency Agile Solar Radiotelescope (FASR) Subsystem Testbed (FST) and observational results are described. Three antennas of Owens Valley Solar Array (OVSA) have been upgraded with newly designed, state of art technology. The 1-9 GHz RF signal from the antenna feed is transmitted via broadband (45 MHz-9.5 GHz) optical fiber links to the control room. The RF is then downconverted to a 500 MHz, single-sideband signal that can be tuned across the 1-9 GHz RF band. The data are sampled with an 8-bit, 1 GHz sampling-rate digitizer, and further saved to a computer hard disk. The full-resolution …

Design And Performance Of Cdma Codes For Multiuser Communications, Radharani Poluri

Dissertations

Walsh and Gold sequences are fixed power codes and are widely used in multiuser CDMA communications. Their popularity is due to the ease of implementation. Availability of these code sets is limited because of their generating kernels. Emerging radio applications like sensor networks or multiple service types in mobile and peer-to-peer communications networks might benefit from flexibilities in code lengths and possible allocation methodologies provided by large set of code libraries.

Walsh codes are linear phase and zero mean with unique number of zero crossings for each sequence within the set. DC sequence is part of the Walsh code set. …

E-Portfolios: Their Impact On Preservice Teachers' Self-Directed Learning And Computer Technology Skills, Yufang Carole Huang

Dissertations

Students in the Teacher Education Program at the University of Missouri-St. Louis have to complete their professional E-portfolios to be certified for the program. An E-portfolio demonstrates a future teacher¿s knowledge, skills, and abilities acquired through teaching and learning. Five qualitative case studies were investigated to understand how E-portfolios impact preservice teachers¿ self-directed learning readiness (SDLR) and computer technology skills (CTS). Data were gathered from the preservice teachers¿ pre- and post-questionnaires, interviews, observations, and their completed E-portfolios. Two internship students and three student teachers were observed creating their E-portfolios during a 16-week semester. During the period, some sought assistance from …

Effect Of Computer-Aided Instruction On Grades In Middle School Algebra, Patricia A. Taepke Edd

Dissertations

Computers and targeted software are increasingly common in the middle school algebra classroom, but the efficacy of computer-aided instruction on classroom achievement in middle school algebra remains unclear. Participants were 1452 middle-school algebra students who were seldom, occasionally, or often exposed to the algebra modules of Destination Math, an interactive mathematics software designed to be appropriate for in-school use. Data were collected over three years (2002–04) and included the cooperation of the algebra teachers, who were subsequently interviewed. Data were analyzed with ANOVA, ANCOVA, and multiple regression. Statistically significant effects were localized using pairwise tests with Bonferroni correction for multiple …

Stakeholders’ Perspectives Of A Catholic K-8 School As A Caring Community, Marci-Anne Hanks Edd

Dissertations

Many educators and researchers have found that caring school communities positively affect students’ behavior, academic achievement, and socioemotional development. Students’ basic needs of feeling cared for must be met for them to realize their full potential. The purpose of this study was to investigate stakeholders’ perceptions of a Catholic K-8 school as a caring community. Stakeholders included parents, teachers, administrators, staff members, and sixth through eighth grade students. The following research questions were posed for this study: (1) What are the different stakeholders’ perceptions of the school as a caring community? (2) Are there significant differences in perceptions between the …

An Investigation Of The Community-Based English Tutoring Program (Cbet), Barbara J. Pongsrikul Edd

Dissertations

Currently in the California K-12 public schools, approximately 25% (about 1.5 million) of the students know little or no English, and their numbers are increasing. Because of this diverse student population, a research study by the Gevirtz Research Center in 2005 reports that it is necessary to develop educational programs that help language-minority families understand and participate in the school system in ways that will support the academic success of their children. As a result of the Proposition 227 Initiative in California, statewide family literacy programs were established as Community-Based English Tutoring (CBET) programs to provide adult English language instruction …

Emerging Elements Of Leadership In A Complex System: A Cognitivist Approach, Kirsten Suzanne Hanson Edd

Dissertations

As our world grows increasingly complicated at an intensified pace, leaders must be facile managers of complexity if organizations and society are to productively and peacefully evolve. Today’s global corporations are microcosms of complexity and have the potential to affect life for almost all other species. However, many organizations have not yet become aware of themselves as “living” and still operate as industrial age institutions with rationalist thinking traditionally dominating management practice. Many factors impact an organization’s overall effectiveness. Yet, executive leaders are seen as having the ability to influence change and play a vital role in helping people navigate …

Bioengineering Of Protein Nanotubes And Protein Nanomaterial Composites, Thilak Kumara Mudalige

Dissertations

Flagella of Mesophilic bacteria such as E. coli are extremely ordered structures consisting of self-assemblies of flagellin 11-mers resulting in protein nanotubes of 2--3 nm inner diameter, 23 nm outer diameter, several microns in length and 5.4 nm separation between 11-mer segments. They are as a result attractive scaffolds and templates for the generation of uniform nanotubes and ordered array of nanoparticles. In this study fusion protein of bacterial flagellin (Fli C) and core thioredoxin (Trx), pFliTrx was used as peptide display on bacterial flagella. This was accomplished in the current research by introducing various peptide loops such as cysteine, …

A Mixed Methods Study On Cbam And The Adoption Of Thin Client Computers By Adolescents, Cynthia Sistek-Chandler Edd

Dissertations

Although stages of change and adoption of innovation dynamics have been examined for adult populations, comparable research for adolescents is limited. Applying a change instrument grounded in Concerns-Based Adoption Model (CBAM) to an adolescent population, this study investigates perceptions of 45 middle school students who used thin client portable computers in a one-to-one program at home and at school for 3 years. A mixed methodology design identified which of the 7 stages of concern students passed through and why some students adopted the innovation more readily than others. The Change Facilitator Stages of Concern Questionnaire, a modified version of CBAM, …

Geophysical Monitoring Probes And Their Applications To Some Hydrogeological Problems, Laura Smart

Dissertations

Geophysical monitoring probes were constructed to monitor the vertical changes of water content and ion concentration in the subsurface. These devices contain electrodes for resistivity measurements and thermistors for temperature measurements. They are designed to monitor the resistivity and temperature of the saturated zone, the transition zone, and the vadose zone near a groundwater/surface water interface. Additional installations at the site include four monitoring wells and four Time Domain Reflectometry (TDR) access tubes, each paired with the geophysical probe installations. Pole-Pole resistivity measurements with an a-spacing of 5 cm are made using a CR1000 Campbell Scientific, Inc. datalogger. Automated data …

Late Pleistocene Climate Variability And Chemical Weathering In The Goriganga, Higher Central Himalaya, North India, Steven Paul Beukema

Dissertations

Relict lacustrine deposits in the Higher Central Himalaya, India, provide a rich repository of paleoclimate information for the period 16 ka to 11 ka. Stable isotope analysis of deposits near the village of Burfu shows the hydrologic balance between glacial meltwater and monsoon precipitation as source waters for the lake. During the period from 15.5 ka to 14 ka the Burfu lake was largely fed by melting glaciers. A warming event correlated to glacial Meltwater Pulse 1a indicates a sudden increase in carbonate weathering in the region accompanied by a gradual decrease in the ratio of glacial meltwater/monsoon precipitation feeding …

Lightweight Intrusion Detection: A Second Line Of Defense For Unguarded Wireless Sensor Networks, Vijay Subhash Bhuse

Dissertations

Wireless sensor networks (WSN) are formed of stationary nodes with stringent resources (in terms of battery power, processor speed, memory and radio range). They have specific communication and traffic patterns.

Making sensor networks secure is especially challenging because of the wireless medium and the fact that WSN is physically unguarded. The compromise of sensor nodes may lead to the loss of secret information and tampering of the software. Hence, intrusion detection techniques must be designed to detect at least some of the most dangerous attacks. Further, these techniques should be lightweight to suit resource constrained nature of WSN.

We focus …

Global And Quantitative Gene Expression Analysis Of The Effects Of Drinking Water Exposure To Lead Acetate In Fisher 344 Male Rats Liver, Worlanyo Eric Gato

Dissertations

The primary objective of this research is to analyze global gene expression patterns occurring in Fisher 344 rat livers exposed to varying levels of lead and times. The hypotheses were that: (1) effects associated with Pb exposure are both dose and time dependent and (2) several genes will be over-expressed or repressed including transcripts associated with calcium signaling. Initially, the effects of Pb exposures upon morphometnc indices, liver and kidney tissue histology, Pb distribution, Pb interaction with other trace metals including Zn, Cu, Co, Fe, Ni and Ca were assessed. Results showed a significant accumulation of lead in blood, liver, …

Conceptual Change Resulting From Experiential Learning With Business Enterprise Software, Thomas F. Rienzo

Dissertations

This study examined business process concept changes in undergraduate business students through an active learning experience with commercial software that is used by industrial companies to optimize and control their business transaction processing. Students that participated in this study were enrolled in an introductory information technology course that employs enterprise resource planning (ERP) software to demonstrate interactions among business processes involved in purchase and sales processing cycles. Specifically, business process comprehension was examined through three interdisciplinary lenses: (1) conceptual change from the discipline of science education, (2) learning styles from the discipline of business management, and (3) technology acceptance from …

What’S So Hard About Algebra? A Grounded Theory Study Of Adult Algebra Learners, Michael Steele Reese Edd

Dissertations

In California community colleges, fewer than half of students who enroll in basic algebra courses finish with a grade of C or better. Such a low success rate creates an intense demand on institutional resources, including faculty efforts, tutorial services, classroom availability, and financial aid. Furthermore, students who do poorly in algebra also tend to struggle in other quantitative courses. While research suggests that child algebra learners tend to exhibit specific misconceptions, not much is known about misconceptions held by adult algebra learners. Research does indicate, however, that certain general learning characteristics are common among adult learners. The present study …

A Collaborative, Hierarchical, Incremental, And Problem Solving Information Systems Development Model, Timothy Joseph Burns

Dissertations

The "software crisis" has been a much discussed and debated topic in Information Systems research. A core cause of the crisis is often identified as the methodologies and approaches used to develop information systems. Thus, over the years a multitude of methodologies have emerged in support of quality software. While many of these methodologies have been effective, research has shown that system development is a highly circumstantial process, and that no one methodology can be optimal in every context of every project. It is also a fact that system development practitioners have employed ad hoc approaches to modify formal methodologies …

Some Contributions On Mimo Radar, Nikolaus Lehmann

Dissertations

Motivated by recent advances in Multiple Input Multiple Output (MIMO) wireless communications, this dissertation aims at exploring the potential of MIMO approaches in the radar context. In communications, MIMO systems combat the fading effects of the multi-path channel with spatial diversity. Further, the scattering environment can be used by such systems to achieve spatial multiplexing. In radar, a complex target consisting of several scatterers takes the place of the multi-path channel of the communication problem. A target's radar cross section (RCS), which determines the amount of returned power, greatly varies with the considered aspect. Those variations significantly impair the detection …

High Resolution Studies Of Complex Solar Active Regions, Na Deng

Dissertations

Flares and Coronal Mass Ejections (CMEs) are energetic events, which can even impact the near-Earth environment and are the principal source of space weather. Most of them originate in solar active regions. The most violent events are produced in sunspots with a complex magnetic field topology. Studying their morphology and dynamics is helpful in understanding the energy accumulation and release mechanisms for flares and CMEs, which are intriguing problems in solar physics.

The study of complex active regions is based on high-resolution observations from space missions and new instruments at the Big Bear Solar Observatory (BBSO). Adaptive optics (AG) in …

Community-Based Evaluation Of The Air Toxic Provisions Of Title Iii Of The 1990 Clean Air Act Amendments : Risks, Costs And Benefits, Keith C. Silverman

Dissertations

Hazardous air pollutants (HAPs) are those pollutants that are known or suspected to cause cancer, serious health effects, or adverse environmental effects. People exposed to HAPs at sufficient concentrations and durations may have an increased risk of getting cancer or experiencing other health effects. The 1990 Amendments to the Clean Air Act (CAAA) directed the U.S. Environmental Protection Agency (USEPA) to use technology-based air pollution control measures to significantly reduce emissions of HAPs from major sources of air pollution, followed by a risk-based assessment to address any remaining or residual health risks.

This study retrospectively assessed the public health risk …

Modeling Projection Neuron And Neuromodulatory Effects On A Rhythmic Neuronal Network, Nicholas Kintos

Dissertations

Projection neurons shape the activity of many neural networks. In particular, neuromodulatory substances, which are often released by projection neurons, alter the cellular and/or synaptic properties within a target network. However, neural networks in turn influence projection neuron input via synaptic feedback. This dissertation uses mathematical and biophysically-realistic modeling to investigate these issues in the gastric mill (chewing) motor network of the crab, Cancer borealis. The projection neuron MCN1 elicits a gastric mill rhythm in which the LG neuron and INTl burst in anti-phase due to their reciprocal inhibition. However, bath application of the neuromodulator PK elicits a similar gastric …

Investigation Of Formation And Applications Of High-Speed Liquid Projectiles, Oleg Petrenko

Dissertations

The work comprises experimental and numerical studies of generation and application of high-speed liquid projectiles. Numerical models were created for a projectile formation by two kinds of launchers, water extruder and water cannon. In the water extruder the kinetic energy of a fast moving piston is transferred to the water load and extrudes the load at a high speed. By contrast in the water cannon the water load itself accumulates the kinetic energy from the expanding combustion gasses. Then, in the course of water motion through the converging nozzle the energy is redistributed between head and tail of the projectile. …

Doppler Spread Estimation In Mobile Fading Channels, Hong Zhang

Dissertations

The Doppler spread, or equivalently, the mobile speed, is a measure of the spectral dispersion of a mobile fading channel. Accurate estimation of the mobile speed is important in wireless mobile applications which require such as knowledge of the rate of channel variations. In this dissertation, first the performance of classical crossing- and covariance-based speed estimators is studied. Next, the problem of mobile speed estimation using diversity combining is investigated. Then, a nonparametric estimation technique is proposed that is robust to different channel variations. Finally, cyclostationarity-based speed estimators which can be applied either blindly or with the aid of pilot …

Small And Large-Scale Magnetic Fields Involved With Solar Flares, Chang Liu

Dissertations

Solar flares are generally identified as an important source of disturbances that affect space weather, while many aspects of the basic flare process are still not well understood. The purpose of the present work has been to investigate the small and large-scale magnetic structures and their evolution associated with flares in the context of magnetic reconnection, based on which the goal of this dissertation is to further the understanding of the various properties of flares and related phenomena, including their origin, precursors, and evolution of morphology in solar atmosphere.

The research presented in this dissertation relied upon multiwavelength observations of …

Flow Characteristics And Phase Interactions Of Evaporating Sprays In Gas-Solid Suspensions, Muhammad Mushahid Rafique Qureshi

Dissertations

Evaporating spray jets have a wide range of applications in many industrial processes such as fluidized catalytic cracking of crude oil in petroleum refinery, coal gasification, fluidized coking to make synthetic crude oil, and condensed mode gas polymerization. The rapid evaporation of spray jets significantly affects the gas-solids mixing, solids concentration, gas/solids temperature and gas/solids velocity acceleration. The complex interactions mechanism of phase change, three phase interaction, heat and mass transfer of gas, solids and evaporating droplets dominate the process efficiency and product quality. In such three-phase flows, the phase transport characteristics are influenced by both droplet-gas interaction and droplet-solid …

Wherry Revisited: An Empirical Examination Of The Nonperformance Factors That Influence Variation In A Performance Rating, Raymond B. Roll Edd

Dissertations

In a perfect performance rating system, both the recall and rating of an individual's behavior would precisely mirror the performance of that ratee. However, the reality of performance rating systems is that often times the rater's recall and subsequent rating fails to reflect the true performance of the individual. The difference between actual and perceived performance has been attributed in the literature to conscious or unconscious rater bias. In 1952, Wherry developed a rating theory based on a series of mathematical equations that precisely defined the relationship between the performance of the ratee and the recall of that observation. Key …

The Relationship Between Emotional Intelligence And Reading Comprehension In High School Students With Learning Disabilities, Helen C. Bryant

Dissertations

Problem. Research indicates that students who receive an exclusively academic education that does not include emotional intelligence skills may not be prepared for future challenges of the 21st century because traditional intelligence contributes to only 20% of the factors that determine life success. Students with learning disabilities have average or above average cognitive intelligence. However, many do not demonstrate academic and social behaviors that normally would be compatible with average intelligence. Even though their cognitive intelligence has been tested, their emotional intelligence has not been tested. The purpose of this study was to investigate the relationship between emotional intelligence and …

Of "Illustrators," "Narrators," "Editors," And "Readers": Describing Relations Between Significantly Disabled Students And Their Peers, Srikala Naraian

Dissertations

This paper interweaves several theoretical strands—disability studies, narrative theories, and sociocultural perspectives on learning—both as a means to understand current practice in the education of students with significant disabilities as well as to envisage other forms of participation for them. The aims of the study are derived from the argument made by Ferguson (2003) that the narratives of others in the lives of severely disabled individuals are critical to the formation of their identities. Appropriating this idea to the classroom, this study explores the notion that the narratives of classroom peers are vital to the participation of the severely disabled …

Transition Activities And Their Effects On Middle School Students, Vicki Sue Vanlaere

Dissertations

The purpose of this study was to determine the effectiveness that transitional activities have on student achievement and attendance when students moved from elementary school to middle school. The data were gathered from two school districts that are demographically similar. Data included average daily attendance rates, Terra Nova Achievement Scores from social studies in grades five, six, and seven, as well as math in grades five, six, and seven. There were 187 students in the Treatment Group and 147 in the Control Group for a total of 334 students. Comparison of means for demographic equivalency of the groups (t-test) and …

A Laptop-Learning Initiative: Relationships With Student Achievement, Technology Proficiency, And Attitude Towards Technology, Kevin Scott Nicholas

Dissertations

The purpose of this study was to investigate the relationships between a laptop learning initiative, student achievement, technology proficiency, and attitude towards technology. The initiative, Project One-on-One, was designed to provide teachers with the ability to teach technology integrated lessons in classrooms with a student-to computer ratio of 1:1. This was accomplished by utilizing two mobile laptop labs that were financed through a national grant competition. The variables that were examined in the study were three years of eighth-grade student achievement scores from the criterion-referenced Louisiana Educational Assessment Program (LEAP) test and the Louisiana Center for Educational Technology’s Technology Proficiency …