Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 44 for “"observed variables"”.
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Structural equation modeling: Predictors of verbal abuse of registered nurses
… verbal abuse in the workplace. Several observed variables were identified to represent the latent constructs. Year in practice and position within the organization were the observed variables for the individual characteristics construct. Workplace aggression tolerance and violence …
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Networked interactions, graphical models and econometrics perspectives in data analysis
… that enables us to determine whether a set of observed variables have a single cause or multiple causes. We also prove that this criterion holds in the presence of confounders, i.e., when the causes are hidden. In the network setting, we assume that the structure of the graph is known. Our …
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Convex optimization methods for graphs and statistical modeling
… of the interactions among a large set of variables. A second major emphasis of this thesis are classes of structured models that satisfy certain algebraic constraints. The common theme underlying these approaches is the development of computational methods based on convex optimization, …
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Modeling Phosphorus Transport in a River Under Unsteady Flow Conditions
… comparing the model predicted results with the observed variables. Various forms of phosphorus flux between the flow and sediment were also simulated, showing the effect of sediment particle size on phosphorus transport. Finally, model parameter sensitivity analysis was carried out within the …
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Modelling the Baltic Sea food web with a Dynamic Bayesian Network with hidden variables
… dynamics. These changes may be driven by unobserved variables, i.e. ecosystem components that we do not have data on. This thesis fits a Dynamic Bayesian Network (DBN) model to one such ecosystem, the Baltic Sea. Three versions of a DBN of the Gotland Basin food web are fitted to data, to …
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Minimal I-MAP MCMC for scalable structure discovery in causal DAG models
… applications, which exhibit a larger number of observed variables than data points. The resulting uncertainty about the underlying network as well as the desire to incorporate prior information recommend a Bayesian approach to learning the BN, but the highly combinatorial structure of BNs poses …
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Bayesian Inference Based on Nonparametric Regression for Highly Correlated and High Dimensional Data
Establishing relationships among observed variables is important in many research studies. However, the task becomes increasingly difficult in the presence of unidentified complexities stemming from interdependencies among multi-dimensional variables and variability across subjects. This …
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Expression of dsr messenger RNA by sulfate reducing bacteria with varying substrate and temperature
… donor and incubation temperature, commonly observed variables known to affect reaction rates. We compare results using formate, an electron donor found in pristine aquifers, to lactate and ethanol, substrates commonly used in laboratory experiments and field biostimulation projects, but …
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Child labour and school attendance: Evidence from selection on observed and unobserved variables in Zambia
… who are not in child labour along an array of observed and unobserved characteristics, I proceed along an alternative path in this paper. I examine the causal effect of long run child labour on children current school attendance using a novel estimation method that assumes that the amount of …
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Identification and Estimation with Deconfounded Instruments
… the causal effects of endogenous (treatment) variables on an outcome variable with partially endogenous instrumental variables. A crucial estimation step called deconfounding recovers variation in the instruments, which is unassociated with some observed variables called proxies, and …
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The Impact of Complications and Errors on Surgeons
… factor analysis confirmed five input variables within the model: event type (complication or error), nature of event (emergency or elective), severity of patient outcome (categorised by Clavien-Dindo score), timeframe of event occurring, and formal investigation. SEM identified three …
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Differences in motivation, self-evaluation, and academic achievement for African American and Caucasian students using structural equation modeling
… models were tested to determine if the observed variables were appropriate measures for their respective latent variables. Structural models were then tested. Results indicated that the proposed model does not correctly define all of the relationships between motivation, self-evaluation, …
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Sinbad Automation Of Scientific Process: From Hidden Factor Analysis To Theory Synthesis
… reveal hidden causal factors controlling the observed phenomena. One major advantage of this approach is that it is not dependent on a particular choice of learning algorithm to use for the computations. The procedures build a theory of the studied subject by finding inferentially useful …
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Multivariate nonparametric estimation on censored panel data
… their method makes the strong assumption that observed variables are uncorrelated with unobserved heterogeneity and that a small number of mass points can represent the sample distribution of unobservables. In their Monte Carlo study, the mass point method failed to estimate the underlying …
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The Impacts of Mobile Phones on the Growth of Informal Sector of economy in Tanzania; A case study of mobile phone users in Lindi region
… the analysis summary the researcher came up with observed variables that explain key issues in each sub theme. A sample size of 64 respondents was used comprising mobile phones users. Findings from the study showed significant increase in income of individual users of mobile phones, growth of the …
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Essays on local labor markets
… at the county level. Using an instrumental-variables approach to correct for both measurement error in entry dates and possible endogeneity of the timing of entry, I find that Wal-Mart entry increases retail employment by 100 jobs in the year of entry. Half of this gain disappears over the …
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Emotional availability (EA) brief: single session feedback and coaching for improving fathers' emotional availability across a wide developmental spectrum
… for the pretests noted above). Across 16 target variables assessing EA, six observed variables showed post-intervention improvement (a < .05) though no significant findings were found on self-reported measures. These findings suggest that fathers respond to programs that provide guidance for …
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Developing interventions for the adoption of solar home systems in rural areas of Vhembe District, South Africa
… to test if the measurement structure of the observed variables fits the hypothesized model. Results revealed that the measurement structure of observed variables passed reliability and validity tests, as measured with Cronbach alpha, Average Variance Extracted (AVE) and Composite Reliability …
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Influences on Health Related Quality of Life in Community Dwelling Adults Aged 60 Years and Over
… factors influencing HRQL. The constructs and observed variables hypothesized to influence HRQL included medical burden, housing satisfaction, socioeconomic status,religion/spirituality, age, gender, and marital status.Three hundred and sixty three (363) participants were drawn from a random …
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Intent to perform protective behaviors to prevent pregnancy in the adolescent female age 13-18
… between the SNA and SA groups response on the observed variables. Determination of variance between the groups was calculated with t tests and revealed statistically significant differences in responses between the SNA and SA groups on all measures. The SNA group were found to have high …
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