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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

Large-Scale Matrix Completion Using Orthogonal Rank-One Matrix Pursuit, Divide-Factor-Combine, and Apache Spark

January 2014 (has links)
abstract: As the size and scope of valuable datasets has exploded across many industries and fields of research in recent years, an increasingly diverse audience has sought out effective tools for their large-scale data analytics needs. Over this period, machine learning researchers have also been very prolific in designing improved algorithms which are capable of finding the hidden structure within these datasets. As consumers of popular Big Data frameworks have sought to apply and benefit from these improved learning algorithms, the problems encountered with the frameworks have motivated a new generation of Big Data tools to address the shortcomings of the previous generation. One important example of this is the improved performance in the newer tools with the large class of machine learning algorithms which are highly iterative in nature. In this thesis project, I set about to implement a low-rank matrix completion algorithm (as an example of a highly iterative algorithm) within a popular Big Data framework, and to evaluate its performance processing the Netflix Prize dataset. I begin by describing several approaches which I attempted, but which did not perform adequately. These include an implementation of the Singular Value Thresholding (SVT) algorithm within the Apache Mahout framework, which runs on top of the Apache Hadoop MapReduce engine. I then describe an approach which uses the Divide-Factor-Combine (DFC) algorithmic framework to parallelize the state-of-the-art low-rank completion algorithm Orthogoal Rank-One Matrix Pursuit (OR1MP) within the Apache Spark engine. I describe the results of a series of tests running this implementation with the Netflix dataset on clusters of various sizes, with various degrees of parallelism. For these experiments, I utilized the Amazon Elastic Compute Cloud (EC2) web service. In the final analysis, I conclude that the Spark DFC + OR1MP implementation does indeed produce competitive results, in both accuracy and performance. In particular, the Spark implementation performs nearly as well as the MATLAB implementation of OR1MP without any parallelism, and improves performance to a significant degree as the parallelism increases. In addition, the experience demonstrates how Spark's flexible programming model makes it straightforward to implement this parallel and iterative machine learning algorithm. / Dissertation/Thesis / M.S. Computer Science 2014
152

Impact of Individualized Learning Plans on Educational Completion Among Incarcerated Youth

D'Anna, Laura Lee 01 January 2018 (has links)
Interruptions to juvenile detainees' education often delay their progress toward high school completion. Implementing an individualized learning plan (ILP) has been suggested as a solution to this problem. The purpose of this case study was to explore how ILPs facilitate attainment of graduation among incarcerated youth. The study was guided by the Washington State legislative framework for individualized learning plans and the efforts of the Office of Juvenile Justice and Delinquency to increase educational opportunities. Three research questions were formulated to explore perceptions of local juvenile detention center educators and administrators regarding their experiences in the development, implementation, and effectiveness of ILPs. Qualitative data were collected from interviews with 5 detention center educators, field observations, and document reviews. The examination of the data through the coding process using a matrix enabled descriptions and themes to emerge. Results indicated that ILPs are collaboratively developed and implemented in the detention center, there is a need for professional development related to ILPs, and ILPs have impacted students' education completion. Results from this study may influence social change by supporting development of ILPs which can result in a higher graduation rate and a reduction in recidivism among the incarcerated youth population.
153

Papel do sistema complemento na diferenciação e maturação das células dendríticas. / Complement system in dendritic cell differentiation and maturation.

Edimara da Silva Reis 28 May 2008 (has links)
O papel do complemento na modulação da resposta de células dendríticas não é bem entendido. Neste trabalho observamos que estas células produzirem proteínas do complemento e que o componente C3 regula positivamente a expressão de DC-SIGN, HLA-DR, CD1a, CD80 e CD86 e a produção de IL-6 e IL-12 por células dendríticas humanas. Também observamos, em modelo murino, menor expressão de MHC-II em células dendríticas C5aR-/-, a qual está associada com menor expressão do transativador de MHC-II; menor expressão de moléculas coestimuladoras nas células C3aR-/-, C5aR-/- e C5L2-/- e menor produção de IL-12p40, IL-12p70 e IL-6 em resposta a ligantes de TLR2 pelas células C3aR-/- e C5aR-/-. Conseqüentemente, a ausência de sinal pelos C3aR e C5aR, regula negativamente a habilidade destas células na indução da resposta de linfócitos T CD4+, modificando os níveis de proliferação e citocinas produzidas. De maneira conjunta, observamos participação do complemento na diferenciação e maturação de células dendríticas e no desenvolvimento da resposta imune adaptativa. / The role of complement in the modulation of dendritic cells functions remains elusive. Here we show that these cells are able to produce complement proteins and that complement C3 upregulates the expression of DC-SIGN, HLA-DR, CD1a, CD80 and CD86 and the production of IL-6 e IL-12 by human dendritic cells. We also observed, in a mouse model, lower expression of MHC-II in C5aR-/- dendritic cells, which is correlated to lower expression of MHC-II transactivator; lower expression of costimmulatory molecules in C3aR-/-, C5aR-/- and C5L2-/- cells and lower production of IL-12p40, IL-12p70 and IL-6 by C3aR-/- and C5aR-/- cells in response to TLR2 stimulation. In consequence to the absence of C3aR and/or C5aR signaling we observed that these cells have lower ability to induce CD4+ T cells proliferation and production of Th1 cytokines. Together our data show a participation of complement in dendritic cell differentiation and maturation and in the polarization of adaptative immune responses.
154

Graduate Nursing Student Persistence to Graduation

Dean, Tyler C. 19 October 2017 (has links)
The purpose of this study was to investigate whether certain student-entry characteristics collected from an admissions application from one nursing school’s graduate (master’s degree) programs had a statistically significant relationship with student persistence. Specifically, the study determined if the variables sex, age at matriculation, U.S. citizenship, state residency status, most recent schooling year, last statistics course taken and grade, graduate-level program of study, and credit hours identified on the graduate nursing admissions application and school transcripts, had a statistically significant relationship in predicting student persistence to graduation. If a relationship existed, it would contribute to graduate student persistence literature and influence how educators and student affairs professionals can identify and support students at risk. The population was the graduate nursing students who enrolled at a large public research university in the Pacific Northwest of the United States during Spring 2005 through the Fall 2009 terms. Graduate students meeting inclusion criteria had data extrapolated from the college’s database; including, the pre-entry characteristics, total credit hours completed, and if (and when) they graduated from their program of study. Astin’s (1985) Input-Environment-Outcomes (I-E-O) Model was the theoretical framework utilized in this study. Out of the 405 graduate nursing students, 257 students (63.5%) graduated within four years from time of matriculation, or 278 students (68.6%) graduated without any time restrictions. Certain pre-entry characteristic data were no longer accessible and not included in the data analysis (most recent schooling year, last statistics course taken and grade). The analysis showed that the age (p < 0.010) and type of graduate program of study one enrolls (p < 0.010) plays an influential role in student persistence to graduation at this nursing school during this time period. In summary, on average, those students who graduated within four years from the time of matriculation were 3.2 years younger than the average age of those who did not complete their graduate program, and the completion rates for practitioner-focused students were higher (66.5-70%) compared to their non-practitioner-focused (46.8-61.3%) counterparts. The results of this study will have an impact on graduate admissions and recruitment, student progression and advising services, and faculty development. Graduate nursing student persistence has multiple implications impacting institutions, communities, and the lives of students. Future opportunities to advancing knowledge on this subject include researching additional pre-entry variables across multi-campus populations with larger sample sizes, longitudinal studies, and interventions to promote persistence.
155

Cooperative Wideband Spectrum Sensing Based on Joint Sparsity

jowkar, ghazaleh 01 January 2017 (has links)
COOPERATIVE WIDEBAND SPECTRUM SENSING BASED ON JOINT SPARSITY By Ghazaleh Jowkar, Master of Science A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University Virginia Commonwealth University 2017 Major Director: Dr. Ruixin Niu, Associate Professor of Department of Electrical and Computer Engineering In this thesis, the problem of wideband spectrum sensing in cognitive radio (CR) networks using sub-Nyquist sampling and sparse signal processing techniques is investigated. To mitigate multi-path fading, it is assumed that a group of spatially dispersed SUs collaborate for wideband spectrum sensing, to determine whether or not a channel is occupied by a primary user (PU). Due to the underutilization of the spectrum by the PUs, the spectrum matrix has only a small number of non-zero rows. In existing state-of-the-art approaches, the spectrum sensing problem was solved using the low-rank matrix completion technique involving matrix nuclear-norm minimization. Motivated by the fact that the spectrum matrix is not only low-rank, but also sparse, a spectrum sensing approach is proposed based on minimizing a mixed-norm of the spectrum matrix instead of low-rank matrix completion to promote the joint sparsity among the column vectors of the spectrum matrix. Simulation results are obtained, which demonstrate that the proposed mixed-norm minimization approach outperforms the low-rank matrix completion based approach, in terms of the PU detection performance. Further we used mixed-norm minimization model in multi time frame detection. Simulation results shows that increasing the number of time frames will increase the detection performance, however, by increasing the number of time frames after a number of times the performance decrease dramatically.
156

Four Essays on a Student's Expectation that they will Complete College

Hunter, Martin Gray 01 January 2017 (has links)
It has been common practice in the economics literature to utilize data on observed outcomes and negate what individuals believe or expect will happen in the future. Using responses to a unique set of questions in the 1997 National Longitudinal Survey of Youth (NLSY97) I show that the literature could benefit in several ways by incorporating such data. The leading essay documents a positive association between a student's subjective probabilistic belief that they will complete a four-year college degree and whether or not they attend and complete college. The results indicate the following. First, although overconfident, individuals as young as fifteen are willing and able to answer subjective probabilistic questions concerning education in a cohesive fashion. Second, these expectations are heterogeneous across race, gender, previous academic success, and parent education, and are influential in predicting whether or not they attend and ultimately complete a degree once these characteristics are controlled for. While the magnitude of the effect diminishes when including the standard economic controls, expectations remain significant and play a larger role as the student ages. Parent expectations are also positive and statistically associated with their child's future college success when the student is young but the significance diminishes as the student ages and gathers information related to the costs and benefits of a college degree. These findings indicate that students possess some form of private information that is not being completely captured by the standard variables used by econometricians to predict college attendance and completion. The second essay uses the NLSY97 to examine how students form and update their college completion expectations as they age out high school. I begin by estimating which factors are utilized by students when forming their expectations while in high school. I find that while these students are taking into account several of the relevant factors associated with college success, they also appear to be neglecting the impact that income and ability have on their likelihood of completing college or are over-relying on poor signals. I then test whether or not students update their expectations in a Bayesian fashion. A Bayesian model is developed. The three ways in which Bayesian students should respond to the acquisition of new information are discussed. Four sources of new information are identified and used in the testing. The testing reveals that students who report either a 0% or 100% chance of completing college do not appear to be Bayesian, but those who report within the 0% and 100% bounds do update in a Bayesian fashion. The third essay studies the accuracy and alignment of the individual's expectation that they will complete college. I utilize several unique aspects of the NLSY97 to create a measure of alignment based on the predicted probability that the respondent will eventually complete college and their expectation of doing so while either in high school or of college age. I use this measure to answer the following questions. First, are there any observable differences between those who are aligned and misaligned? Next, do respondents become more aligned as they age and progress out of high school? Last, are those who are more aligned at an early age more likely to reach their outcomes? I find that although the majority of students are overconfident in their belief there are considerable differences in alignment based on several observable characteristics and the availability of information. The alignment of student expectations differ based on parent education, ASVAB percentile, school enrollment, and race. Using two sub-samples of different aged respondents I show that as students age and acquire more information their expectation of completing college becomes more aligned with their estimated probability of completion. I confirm this by examining 700 students who are asked their expectations first in 1997 while in high school then again five years later when they either are in college or the workforce. I conclude by showing that those who are more aligned in either direction with what a model of college completion predicts the more likely they are to eventually reach that outcome. The final essay examines if the private information contained in the student's expectation that they will complete college is associated with future early career earnings. First I note that there are considerable differences in the frequency of reporting, yearly income, hours worked, and hourly wage for those who predict college success and are successful versus those who do not, as well as those who accurately predict that they will not complete college. I then include these expectations in a wage regression and the estimates suggest that when individuals report their college completion expectations between the ages of 15 and 17 they are not associated with future earnings. However, when asked between the ages of 17 and 22 the reported expectations are positively associated with future wages. There is considerable heterogeneity based on gender, whether they reported at one of the three primary heaping points, and the quantile of the wage distribution in which they were located.
157

Interventions aimed at enhancing supervision capacity : a systematic review (2000-2013)

Trimble, Lyle January 2015 (has links)
Magister Artium (Psychology) - MA(Psych) / Literature suggests that novice supervisors are not adequately trained or equipped with the skills required in research supervision or to become productive researchers, and recommend that intervention strategies aimed specifically at enhancing supervision capacity, be prioritized. Primary texts report positive effects on student output and timely completion in a range of intervention strategies aimed at enhancing supervision capacity including supervisor training. However, it is difficult to compare these individual reports without a systematic attempt at filtration in which studies are evaluated for methodological rigour. The aim of this study was to consolidate the body of literature reporting on strategies aimed at enhancing supervision capacity which satisfies a threshold of methodological quality. The present study was a systematic review evaluating published literature from 2003 to 2013 that report on strategies aimed at enhancing supervision capacity. Only full-text, English articles within the UWC library databases were considered for inclusion provided that they report on the specified target group and focus of the study. Identified articles were evaluated on three levels: titles, abstract, and full text. Four instruments were used to facilitate data extraction and quality assessment including a Title summary sheet, abstract summary sheet, critical appraisal tool, and data extraction sheet. Meta-synthesis of included texts was conducted. Ethics: Permission to conduct the study was obtained from the appropriate committees at the University of the Western Cape (Registration number: 14/5/18). The information sources used in this study were all previously published and are in the public domain; therefore no additional permission for access was required. The study formed part of a larger NRF funded parent study. Thus the distinction between collaboration and plagiarism was carefully monitored given the collaboration between the present study and the larger parent study.
158

Purchase Price Mechanisms / Mechanizmy upravy kupnej ceny

Gajdošech, Martin January 2012 (has links)
My diploma thesis focuses on the M&A transaction closing mechanisms. Their function is to reflect the value changes of the target company into the purchase price. Value change occurs during the time lag between the date of the financial statements and the date of the transaction closing. Throughout history, there have been two major approaches developed. The "Completion Accounts Mechanism" uses post-completion price adjustments to reflect the change of the net working capital and net debt during the interim period. The "Locked Box Mechanism", using fixed price, assures non-fluctuation of target value in the interim period by imposing strict restrictions on the seller's activities. In this research, I have analyzed 44 transactions closed in the Czech Republic. I have challenged the theoretical foundations and described the application of the mechanisms in practice. At the end, I have compared the Czech and European practices. Thesis findings: 1. All the theoretical features of the mechanisms were proven by an analyzed sample of closed transactions. The completion accounts mechanism is buyer-friendly, while the locked box is a seller-friendly mechanism. 2. The main driver in mechanism selection is bargaining power. Buyers were in a better negotiating position in 69% of the completion account transactions. On the contrary, the sellers had bargaining power in 100% of the locked box transactions. 3. The Czech Republic is an environment where buyers (big multinational companies) dominate. They have preferred the completion account mechanism that provides them with higher protection from value leakage or other risks associated with small CEE economies. A total of 91% of analyzed transactions were executed by the completion account mechanism in the Czech Republic between 2011 and 2012.
159

Student Variables Contributing to Program Completion in Career School Sector For-Profit Schools

Eatman, Timothy Allen 08 1900 (has links)
The general purpose of the study was to compile current descriptive information for recent graduates from career school sector institutions that reveals the significant factors which contributed to their program completion. The research project focused upon career school program completers. The scope of the study was directed to recent program completers at two career schools in Texas which offer a cross-section of programs designed to provide students specific skills for immediate employment. Based upon an extensive review of literature and the input of a focus group of experienced career school administrators and faculty members, seven variables were determined to be worthy of a focused study of their possible contributions to career school program completion. The variables were ability to accept responsibility for completion, academic preparedness, family or friends support system, self-esteem, life skills preparedness, sense of being goal-oriented, and sense of connectedness to the school. It was determined that each of the seven variables existed prominently in the majority of these recent graduates. The researcher concludes that there is a tremendous need for continued study that is focused on career school sector students. The paper offers the suggestion of a specific retention program that can be employed by career school administrators to emphasize the 7 variables and implement specific interventions designed to increase student retention and program completion.
160

Contributions of Target-Lure Similarity and Sensory Modality to Lure False Alarms

Bjornn, Daniel Kent 01 December 2018 (has links)
The processes of pattern separation and pattern completion are very important in the correct discrimination of similar memories. Much research has been conducted on these processes, but there are some gaps that need to be addressed. First, there is some debate as to whether false alarms to lure items come about because of a failure to accurately encode a memory or a failure to retrieve a memory. Second, much of the research on pattern separation and pattern completion in humans is done with visual stimuli and contributions of stimulus modality to these processes are not well understood as a result.Study 1 consisted of three experiments conducted using a combination of eye tracking and functional magnetic resonance imaging (fMRI) methods. Analyses of eye tracking data in the experiments examined the contribution of fixation counts at encoding and retrieval, as well as target-lure similarity level, to accuracy on lure trials. Task designs were altered across studies to attempt to replicate specific research previously conducted with a specific answer period, as well as generalize the findings to a broader body of research that allows participants to answer while the stimulus is presented. The three experiments showed mixed support for the contribution of fixation counts at encoding and retrieval to the accurate discrimination of similar lures. Target- lure similarity, however, was a robust predictor of accuracy for all three experiments.Prior research examining activity in the hippocampus demonstrates a reduction of fMRI activity to repetitions of a stimulus. Greater activity is also observed in the dentate gyrus/CA3 (DG/CA3) subregions for correct rejections of lure items compared to lure false alarms. There should be a greater reduction in the DG/CA3 as a function of encoding for lure false alarms than for lure correct rejections if memory encoding drives the activity differences between these outcomes. The fMRI data showed a marked reduction of activity in the left hippocampus to repetition trials as a function of encoding trial fixation count. There was no significant difference between activity as a function of encoding fixation count in the DG/CA3 for lure correct rejections and lure false alarms. There was also no difference in activity for the CA1 either. Overall, the results of the eye tracking and fMRI data give support for the contribution of pattern completion to false alarms to lure stimuli rather than poor encoding.Study 2 examined the contribution of sensory modality to accurate discriminations of lure stimuli. A behavioral task was developed to directly compare discrimination of similar lures on visual and auditory stimuli. Participants were significantly more accurate and more confident of their responses when discriminating visual stimuli as compared to discriminating auditory stimuli.

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