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.
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Showing 1 to 20 of 237 for “"hurdle"”.
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Bayesian methods for hurdle models.
Hurdle models are often presented as an alternative to zero-inflated models for count data with excess zeros. They consist of two parts: a binary model indicating a positive response (the "hurdle") and a zero-truncated count model. One or both parts of the model can depend on covariates, which may …
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Component-wise Z-residual Diagnosis for Bayesian Hurdle Models
… often perform poorly when zero counts dominate. Hurdle models provide a flexible solution by separating the modeling process into two parts: (1) a binary model that predicts whether the count is zero or positive, and (2) a zero-truncated model that describes the distribution of positive counts. …
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Development of regional reliability hurdle rate for South Africa
… to this thesis has been to develop reliability hurdle rates that include the effect of the IBR scheme implemented by the national regulator authority of South Africa. This will enable the network planner to compare the investment decision with the reward / penalty scheme. The thesis addresses …
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Investigaion of the Gamma Hurdle Model for a Single Population Mean
… to deal with the presence of zeroes is using a hurdle model. Most literary work on hurdle models will focus on modeling the frequency of zeros separate from the nonnegative values. While this approach has some advantages, it doesn’t typically provide an interval estimator for the global …
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Preparation of juice concentrates by nonthermal processing technologies: a multiple hurdle approach
The conventional preparation of juice concentrates is by thermal evaporation. However, some quality attributes, nutrients, bioactive components, and other volatile compounds are degraded due to prolonged exposure to high temperatures. This leads to the investigation of the membrane separation …
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Hurdle Technologies Using Essential Oils And High Hydrostatic Pressure To Inactivate E. Coli In Fresh Beef
In this study, potential of high hydrostatic pressure (HHP) and essential oils (EOs) as natural antimicrobials was evaluated to produce E. coli safe and quality beef product. First, the individual and combined effects of antimicrobial activity (minimum inhibitory concentration) of basil, black …
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The Elimination of Listeria monocytogenes Biofilms from Stainless Steel Deli Meat Slicer Components by the use of Hurdle Technologies
<p>Listeria monocytogenes growth is of the greatest concern amongst ready-to-eat foods. The United States Department of Agriculture's Food Safety and Inspection Services determined that deli luncheon meats pose the greatest risk of contamination from L. monocytogenes Industrial meat slicers have …
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Over the hurdle: A quantitative study examining the obstacles of achieving professional certification and the perceived effective practices for overcoming them
<p>The purpose of this study was to identify the issues that Information Systems (IS) professionals face when pursuing professional certification as well as the perceived effective practices to overcome these issues. I have observed many students seeking professional certification while only a …
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Commercial Considerations for Space Resource Utilisation in the Context of Mining Feasibility Studies
… for such activity. Potential investment hurdle rate requirements for commercial involvement in SRU are investigated, with a hurdle rate range around 25% being proposed, along with the use of a standardised discount rate of 10%. A mechanism, the Risk Build Up Method, is developed to assist …
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A Biomechanical Analysis of Male and Female Intermediate Hurdlers and Steeplechasers
… events of different lengths. The intermediate hurdles (IH) and the steeplechase (SC) are two events where there are a number of differences in hurdling technique. This study compared the differences in hurdling technique between events (IH and SC) as well as the differences in technique between …
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The search for new axioms
… to set up a mathematically precise minimal hurdle which any set of new axioms must overcome if it is to effect a significant reduction in incompleteness. In Chapter 3 I examine the standard method of justifying new axioms-reflection principles-and prove a result which shows that no …
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The economics of alcohol : a collection of essays
… different methods including the Tobit and Double-Hurdle models to estimate the mean price elasticity of demand for alcohol. In doing so, it tests how the price elasticity estimates can differ depending on model choice, even when the same data is used. Household expenditure data contains a large …
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Modified mean and quantile regression models for citation analysis
… challenges, an update of the Bayesian two-part hurdle QR introduced by King and Song (2019a) is proposed. The original Bayesian two-part QR with hurdle at zero was introduced for count data with a mass point at zero. For citation counts, there are also substantial mass points at one, two, and …
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Establishing associations for the evaluation of mobility screen (EMS) in an adult South African population
… effect (p < 0.05) on five subtests (Single Leg Hurdle, Shoulder Mobility, Asymmetric Leg Raise, Stability Push Up and Seated Rotation). Age had a significant effect (p < 0.05) on three subtests (Overhead Squat, Single Leg, Hurdle Split Squat). Physical activity level had a significant effect (p …
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High Voltage Synchronous Rectifier Design Considerations
… (2) light load effects; (3) accuracy. The first hurdle to designing a high voltage SR system is the high voltage itself. Traditional methods of synchronous rectification (SR) attempt to directly sense voltage or current, which is not possible with high voltage. Therefore, a solution must be …
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Advancing the Development and Utilization of Data Infrastructure for Smart Homes
… of publicly available data remains a major hurdle in the domain, limiting people's capability of performing data analysis and their effectiveness in creating smart home automations. To mitigate this hurdle and its influence, our research explored three research directions to (1) create a …
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Design and Model-based Approaches for Estimating Abundance of American Horseshoe Crab
… design. In Chapter 1 of this work, I developed hurdle models for each of the six HSC demographic groups to standardize catch-per-unit-effort (CPUE) and estimate relative abundance using a model-based approach. It was determined that while the two approaches resulted in mostly convergent …
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The Development of Leadership Skills of African American Women in Sororities: University Responsibility
<p>Abstract</p><p>Since their inception colleges and universities have taken on the role of developing their students as leaders and good citizens, through their leadership programming. However, the theoretical frameworks utilized within these programs have excluded groups that have been …
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Variants of compound models and their application to citation analysis
… fixed parameters. Comparisons of SVA, Poisson hurdle, negative binomial hurdle and their zero-inflated counterpart using simulated SVA data indicate that different models can give similar results, as the generating models are not always selected as the best fitting. This thesis focuses on the …
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Development of an isotope-sensitive warhead verification technique using nuclear resonance fluorescence
… reduction will face an additional technological hurdle: no technology exists to verify that warheads slated for dismantlement are authentic without revealing any sensitive weapons design information in the process. Despite several decades of research, no technology has solved this apparent …
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