You searched for subject:(truncation).
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1.
Ziaul Haque.
Characterization of distributions and related
results; -.
Degree: Statistics, 2010, Aligarh Muslim University
URL: http://shodhganga.inflibnet.ac.in/handle/10603/12945 
► In applied statistics, one observes a random quantity X , a number of times and based on these observations, one would like to conclude facts…
(more)
▼ In applied statistics, one observes a random
quantity X , a number of times and based on these observations, one
would like to conclude facts about the distribution function ) (x F
of X . The usual approach is to start with a family
and#61510;and#61472;of distributions and to select from this family
a distribution ) (x F which is the most acceptable one in a given
sense. Unfortunately in many cases and#61510;and#61472;simply
consist of a single function which is dependent on one or several
parameters and the observations are used merely to approximate its
parameters. The function thus obtained is chosen as ) (x F
[Galambos and Kotz, 1978]. Characterization is a condition
involving certain properties of a random variables ) , , , ( 2 1 n
X X X X K and#61501;and#61472;, which identifies the associated
distribution function ) (x F . The property that uniquely
determines ) (x F may be based on a function of random variables
whose joint distribution is related to that of ) , , , ( 2 1 n X X
X X K and#61501;and#61472;. newlineThe only method of finding
distribution function ) (x F exactly, which avoids the subjective
choice, is a characterization theorem. A theorem is on a
characterization of a distribution function if it concludes that a
set of conditions is satisfied by ) (x F and only by ) (x F .
Another important consequence of characterization theorem is that
these results help us in better understanding the structures and
implications of the choice of distribution for a special problem.
With this in view, some distributions here are characterized
through records, order statistics, generalized order statistics and
dual generalized order statistics.Main contributors for
characterizations through order statistics are: newlineFerguson
(1967), Shanbhag (1970), Hamdan (1972), Beg and Kirmani (1978),
Khan and Khan (1986), Khan and Beg (1987), Khan and Ali (1987),
Nagaraja (1988), Khan and Abu-Salih (1989), Ouyang and Wu (1996),
Franco and Ruiz (1995, 1997), Blaquez and Rebollo (1997),
Wesolowski and Ahsanullah (1997), Dembiand#324;ska and Wesolowski
(1998) and Khan and Abouammoh (2000), Lee et al.
(2002)
References p.119-128
Advisors/Committee Members: Abdul Hamid Khan.
Subjects/Keywords: Statistics; Truncation; Order Statistics
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APA (6th Edition):
Haque, Z. (2010). Characterization of distributions and related
results; -. (Thesis). Aligarh Muslim University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/12945
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Haque, Ziaul. “Characterization of distributions and related
results; -.” 2010. Thesis, Aligarh Muslim University. Accessed January 24, 2021.
http://shodhganga.inflibnet.ac.in/handle/10603/12945.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Haque, Ziaul. “Characterization of distributions and related
results; -.” 2010. Web. 24 Jan 2021.
Vancouver:
Haque Z. Characterization of distributions and related
results; -. [Internet] [Thesis]. Aligarh Muslim University; 2010. [cited 2021 Jan 24].
Available from: http://shodhganga.inflibnet.ac.in/handle/10603/12945.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Haque Z. Characterization of distributions and related
results; -. [Thesis]. Aligarh Muslim University; 2010. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/12945
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Northeastern University
2.
Helfand, Ilanit Shtull-Leber.
Constructions of k-orbit abstract polytopes.
Degree: PhD, Department of Mathematics, 2013, Northeastern University
URL: http://hdl.handle.net/2047/d20003089
► The desire to derive new polytopes from old polytopes dates back to the classical study of polytopes, as many of the Archimedian solids can be…
(more)
▼ The desire to derive new polytopes from old polytopes dates back to the classical study of polytopes, as many of the Archimedian solids can be obtained from Platonic solids through the act of truncation. In this dissertation, we apply these ideas to the setting of abstract polytopes. We present a number of constructions of abstract polytopes, which will generally share some properties with the polytopes from which they were derived. Most notably, we are interested in the circumstances under which the automorphism group of the derived polytope is isomorphic to the automorphism group of the original polytope. We construct polytopes called k-bubbles which generalize truncated polytopes, and which will generally have k flag-orbits and retain the automorphism group of the polytopes from which they are derived. Additionally, among the polytopes that we will construct will be examples of two-orbit polytopes, as well as semiregular polytopes, which we can construct given a preassigned automorphism group. We will also construct polytopes with k flag-orbits, for arbitrary k, with a preassigned automorphism group. Finally, we focus on k-orbit polytopes whose automorphism groups are certain quotients of Coxeter groups called string C-groups. We will prove that there almost always exists a k-orbit polytope whose automorphism group is a given string C-group. In particular, we will prove that in every odd rank there is exactly one counterexample.
Subjects/Keywords: Orbit; Polytopes; Truncation; Mathematics
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APA (6th Edition):
Helfand, I. S. (2013). Constructions of k-orbit abstract polytopes. (Doctoral Dissertation). Northeastern University. Retrieved from http://hdl.handle.net/2047/d20003089
Chicago Manual of Style (16th Edition):
Helfand, Ilanit Shtull-Leber. “Constructions of k-orbit abstract polytopes.” 2013. Doctoral Dissertation, Northeastern University. Accessed January 24, 2021.
http://hdl.handle.net/2047/d20003089.
MLA Handbook (7th Edition):
Helfand, Ilanit Shtull-Leber. “Constructions of k-orbit abstract polytopes.” 2013. Web. 24 Jan 2021.
Vancouver:
Helfand IS. Constructions of k-orbit abstract polytopes. [Internet] [Doctoral dissertation]. Northeastern University; 2013. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2047/d20003089.
Council of Science Editors:
Helfand IS. Constructions of k-orbit abstract polytopes. [Doctoral Dissertation]. Northeastern University; 2013. Available from: http://hdl.handle.net/2047/d20003089
Virginia Tech
3.
Gautham, Tejaswini.
Residual-Based Discretization Error Estimation for Unsteady Flows.
Degree: MS, Aerospace Engineering, 2020, Virginia Tech
URL: http://hdl.handle.net/10919/96400
► Computational fluid dynamics (CFD) is a tool that is widely used in most industries today. It is used to understand complex flows that are difficult…
(more)
▼ Computational fluid dynamics (CFD) is a tool that is widely used in most industries today. It is used to understand complex flows that are difficult to replicate using experimental techniques or by theoretical methods. It is important to have rigorous techniques to estimate the error produced when using CFD even when the exact solution is not available for comparison. This paper develops techniques to estimate discretization error for unsteady flows. Discretization error has one of the largest error magnitudes in CFD solutions. The exact physics dictates the use of continuous equations but to apply CFD techniques, the continuous equations have to be converted to discrete equations.
Truncation error is, the error obtained when converting the continuous equations to discrete equations. This
truncation error is in turn, the local source term for discretization error. To reduce the discretization error in the discrete equations, the exact or estimated
truncation error is either added as a source term to the discrete equations or is used along with the error transport equation to get a better estimate of the solutions. A framework to obtain exact
truncation error and estimated
truncation error is also presented. The framework is first applied to the steady equations and is verified with results from previous studies and is then extended to the unsteady flows.
Advisors/Committee Members: Roy, Christopher John (committeechair), Xiao, Heng (committee member), Borggaard, Jeffrey T. (committee member).
Subjects/Keywords: CFD; truncation error; discretization error
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APA (6th Edition):
Gautham, T. (2020). Residual-Based Discretization Error Estimation for Unsteady Flows. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/96400
Chicago Manual of Style (16th Edition):
Gautham, Tejaswini. “Residual-Based Discretization Error Estimation for Unsteady Flows.” 2020. Masters Thesis, Virginia Tech. Accessed January 24, 2021.
http://hdl.handle.net/10919/96400.
MLA Handbook (7th Edition):
Gautham, Tejaswini. “Residual-Based Discretization Error Estimation for Unsteady Flows.” 2020. Web. 24 Jan 2021.
Vancouver:
Gautham T. Residual-Based Discretization Error Estimation for Unsteady Flows. [Internet] [Masters thesis]. Virginia Tech; 2020. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/10919/96400.
Council of Science Editors:
Gautham T. Residual-Based Discretization Error Estimation for Unsteady Flows. [Masters Thesis]. Virginia Tech; 2020. Available from: http://hdl.handle.net/10919/96400
Virginia Tech
4.
Tyson, William Conrad.
Application of r-Adaptation Techniques for Discretization Error Improvement in CFD.
Degree: MS, Aerospace and Ocean Engineering, 2015, Virginia Tech
URL: http://hdl.handle.net/10919/78061
► Computational fluid dynamics (CFD) has proven to be an invaluable tool for both engineering design and analysis. As the performance of engineering devices become more…
(more)
▼ Computational fluid dynamics (CFD) has proven to be an invaluable tool for both engineering design and analysis. As the performance of engineering devices become more reliant upon the accuracy of CFD simulations, it is necessary to not only quantify and but also to reduce the numerical error present in a solution. Discretization error is often the primary source of numerical error. Discretization error is introduced locally into the solution by
truncation error.
Truncation error represents the higher order terms in an infinite series which are truncated during the discretization of the continuous governing equations of a model. Discretization error can be reduced through uniform grid refinement but is often impractical for typical engineering problems. Grid adaptation provides an efficient means for improving solution accuracy without the exponential increase in computational time associated with uniform grid refinement. Solution accuracy can be improved through local grid refinement, often referred to as h-adaptation, or by node relocation in the computational domain, often referred to as r-adaptation. The goal of this work is to examine the effectiveness of several r-adaptation techniques for reducing discretization error. A framework for geometry preservation is presented, and
truncation error is used to drive adaptation. Sample problems include both subsonic and supersonic inviscid flows. Discretization error reductions of up to an order of magnitude are achieved on adapted grids.
Advisors/Committee Members: Roy, Christopher John (committeechair), Borggaard, Jeffrey T. (committee member), Xiao, Heng (committee member).
Subjects/Keywords: CFD; mesh adaptation; truncation error; discretization error
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APA ·
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APA (6th Edition):
Tyson, W. C. (2015). Application of r-Adaptation Techniques for Discretization Error Improvement in CFD. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/78061
Chicago Manual of Style (16th Edition):
Tyson, William Conrad. “Application of r-Adaptation Techniques for Discretization Error Improvement in CFD.” 2015. Masters Thesis, Virginia Tech. Accessed January 24, 2021.
http://hdl.handle.net/10919/78061.
MLA Handbook (7th Edition):
Tyson, William Conrad. “Application of r-Adaptation Techniques for Discretization Error Improvement in CFD.” 2015. Web. 24 Jan 2021.
Vancouver:
Tyson WC. Application of r-Adaptation Techniques for Discretization Error Improvement in CFD. [Internet] [Masters thesis]. Virginia Tech; 2015. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/10919/78061.
Council of Science Editors:
Tyson WC. Application of r-Adaptation Techniques for Discretization Error Improvement in CFD. [Masters Thesis]. Virginia Tech; 2015. Available from: http://hdl.handle.net/10919/78061
University of Edinburgh
5.
Murray, Aja Louise.
Construct truncation due to suboptimal person and item selection : consequences and potential solutions.
Degree: PhD, 2016, University of Edinburgh
URL: http://hdl.handle.net/1842/33129
► Construct truncation can be defined as the failure to capture variation along the entire continuum of a construct reliably. It can occur due to suboptimal…
(more)
▼ Construct truncation can be defined as the failure to capture variation along the entire continuum of a construct reliably. It can occur due to suboptimal person selection or due to suboptimal item selection. In this thesis, I used a series of simulation studies coupled with real data examples to characterise the consequences of construct truncation on the inferences made in empirical research. The analyses suggested that construct truncation has the potential to result in significant distortions of substantive conclusions. Based on these analyses I developed recommendations for anticipating the circumstances under which construct truncation is likely to be problematic, identifying it when it occurs, and mitigating its adverse effects on substantive conclusions drawn from affected data.
Subjects/Keywords: 158.1; construct truncation; sampling; self-selection
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APA (6th Edition):
Murray, A. L. (2016). Construct truncation due to suboptimal person and item selection : consequences and potential solutions. (Doctoral Dissertation). University of Edinburgh. Retrieved from http://hdl.handle.net/1842/33129
Chicago Manual of Style (16th Edition):
Murray, Aja Louise. “Construct truncation due to suboptimal person and item selection : consequences and potential solutions.” 2016. Doctoral Dissertation, University of Edinburgh. Accessed January 24, 2021.
http://hdl.handle.net/1842/33129.
MLA Handbook (7th Edition):
Murray, Aja Louise. “Construct truncation due to suboptimal person and item selection : consequences and potential solutions.” 2016. Web. 24 Jan 2021.
Vancouver:
Murray AL. Construct truncation due to suboptimal person and item selection : consequences and potential solutions. [Internet] [Doctoral dissertation]. University of Edinburgh; 2016. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/1842/33129.
Council of Science Editors:
Murray AL. Construct truncation due to suboptimal person and item selection : consequences and potential solutions. [Doctoral Dissertation]. University of Edinburgh; 2016. Available from: http://hdl.handle.net/1842/33129
University of Utah
6.
Mao, Yanfei.
Segmented parallel and slant-hole stationary cardiac single photon emission computed tomography.
Degree: PhD, Bioengineering, 2015, University of Utah
URL: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/3722/rec/2151
► Single Photon Emission Computed Tomography (SPECT) myocardial perfusion imaging (MPI), a noninvasive and effective method for diagnosing coronary artery disease (CAD), is the most commonly…
(more)
▼ Single Photon Emission Computed Tomography (SPECT) myocardial perfusion imaging (MPI), a noninvasive and effective method for diagnosing coronary artery disease (CAD), is the most commonly performed SPECT procedure. Hence, it is not surprising that there is a tremendous market need for dedicated cardiac SPECT scanners. In this dissertation, a novel dedicated stationary cardiac SPECT system that using a segmented-parallel-hole collimator is investigated in detail. This stationary SPECT system can acquire true dynamic SPECT images and is inexpensive to build. A segmented-parallel-hole collimator was designed to fit the existing general-purpose SPECT cameras without any mechanical modifications of the scanner while providing higher detection sensitivity. With a segmented-parallel-hole collimator, each detector was segmented to seven sub-detector regions, providing seven projections simultaneously. Fourteen view-angles over 180 degree were obtained in total with two detectors positioned at 90 degree apart. The whole system was able to provide an approximate 34-fold gain in sensitivity over the conventional single-head SPECT system. The potential drawbacks of the stationary cardiac SPECT system are data truncation from small field of view (FOV) and limited number of view angles. A tailored maximum-likelihood expectation-maximization (ML-EM) algorithm was derived for reconstruction of truncated projections with few view angles. The artifacts caused by truncation and insufficient number of views were suppressed by reducing the image updating step sizes of the pixels outside the FOV. The performance of the tailored ML-EM algorithm was verified by computer simulations and phantom experiments. Compared with the conventional ML-EM algorithm, the tailored ML-EM algorithm successfully suppresses the streak artifacts outside the FOV and reduces the distortion inside the FOV. At 10 views, the tailored ML-EM algorithm has a much lower mean squared error (MSE) and higher relative contrast. In addition, special attention was given to handle the zero-valued projections in the image reconstruction. There are two categories of zero values in the projection data: one is outside the boundary of the object and the other is inside the object region, which is caused by count starvation. A positive weighting factor c was introduced to the ML-EM algorithm. By setting c>1 for zero values outside the projection, the boundary in the image is well preserved even at extremely low iterations. The black lines, caused by the zero values inside the object region, are completely removed by setting 0< c
Subjects/Keywords: Calibration; Cardiac SPECT; ML-EM; Monte Carlo; Reconstruction; Truncation
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APA (6th Edition):
Mao, Y. (2015). Segmented parallel and slant-hole stationary cardiac single photon emission computed tomography. (Doctoral Dissertation). University of Utah. Retrieved from http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/3722/rec/2151
Chicago Manual of Style (16th Edition):
Mao, Yanfei. “Segmented parallel and slant-hole stationary cardiac single photon emission computed tomography.” 2015. Doctoral Dissertation, University of Utah. Accessed January 24, 2021.
http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/3722/rec/2151.
MLA Handbook (7th Edition):
Mao, Yanfei. “Segmented parallel and slant-hole stationary cardiac single photon emission computed tomography.” 2015. Web. 24 Jan 2021.
Vancouver:
Mao Y. Segmented parallel and slant-hole stationary cardiac single photon emission computed tomography. [Internet] [Doctoral dissertation]. University of Utah; 2015. [cited 2021 Jan 24].
Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/3722/rec/2151.
Council of Science Editors:
Mao Y. Segmented parallel and slant-hole stationary cardiac single photon emission computed tomography. [Doctoral Dissertation]. University of Utah; 2015. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/3722/rec/2151
Texas A&M University
7.
Krueger, Aaron Martin.
ESTIMATION OF DISCRETIZATION ERROR FOR THREE DIMENSIONAL CFD SIMULATIONS USING A TAYLOR SERIES MODIFIED EQUATION ANALYSIS.
Degree: MS, Nuclear Engineering, 2017, Texas A&M University
URL: http://hdl.handle.net/1969.1/169608
► The Consortium for Advanced Simulation of LightWater Reactors (CASL) is working towards developing a virtual reactor called the Virtual Environment for Reactor Application (VERA). As…
(more)
▼ The Consortium for Advanced Simulation of LightWater Reactors (CASL) is working
towards developing a virtual reactor called the Virtual Environment for Reactor Application
(VERA). As part of this work, computational fluid dynamics (CFD) simulations are
being made to inform lower fidelity models to predict heat transfer and fluid flow through
a light water reactor core. A 5x5 fuel rod assembly with mixing vanes was chosen to
represent a 17x17 fuel rod assembly. Even with this simplified geometry, it is estimated
that hundreds of millions of cells are needed for a solution to be close to the asymptotic
region. The large number of cells is an issue when completing solution verification studies
because of computational cost.
Solution verification studies traditionally involve the use of Roache’s grid convergence
index (GCI) to estimate the error, but require the solution to be in the asymptotic region.
This is a severely limiting restriction for simulations with large range of length scales as is
the case with the 5x5 fuel rod assembly with mixing vanes. Unfortunately, GCI does not
perform well when the solution is outside the asymptotic region. However, a new method
called the robust multi-regression (RMR) solution verification method has the potential to
produce good results, even when the solution is outside the asymptotic region.
This study builds a software framework that improves the RMR solution verification
analysis by improving the error model used to estimate the discretization error. Previous
RMR work used a power function to model the error, which was the same function used
in the Richardson extrapolation. The power function form is a result of a Taylor series
expansion on a uniform grid for simple numerical schemes and physics. It can be improved
by completing a Taylor series expansion for the numerical scheme, boundary conditions,
and physics that are being employed in the simulation of interest. This framework was shown to improve the ability for the error model to estimate the discretization error and
uncertainty. The improved error model was able to predict error on a refined grid within
the uncertainty bounds, while the standard error model did not. In addition, the method
of manufactured modified equation analysis solutions (MMMEAS) was developed and
applied to justify the use of a down selection method for terms in the error model.
Advisors/Committee Members: Hassan, Yassin (advisor), Chen, Hamn-Ching (committee member), Vaghetto, Rodolfo (committee member), Mousseau, Vincent (committee member).
Subjects/Keywords: Solution Verification; Uncertainty Quantification; Discretization Error; Truncation Error; Modified Equation Analysis
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APA ·
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Manager
APA (6th Edition):
Krueger, A. M. (2017). ESTIMATION OF DISCRETIZATION ERROR FOR THREE DIMENSIONAL CFD SIMULATIONS USING A TAYLOR SERIES MODIFIED EQUATION ANALYSIS. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/169608
Chicago Manual of Style (16th Edition):
Krueger, Aaron Martin. “ESTIMATION OF DISCRETIZATION ERROR FOR THREE DIMENSIONAL CFD SIMULATIONS USING A TAYLOR SERIES MODIFIED EQUATION ANALYSIS.” 2017. Masters Thesis, Texas A&M University. Accessed January 24, 2021.
http://hdl.handle.net/1969.1/169608.
MLA Handbook (7th Edition):
Krueger, Aaron Martin. “ESTIMATION OF DISCRETIZATION ERROR FOR THREE DIMENSIONAL CFD SIMULATIONS USING A TAYLOR SERIES MODIFIED EQUATION ANALYSIS.” 2017. Web. 24 Jan 2021.
Vancouver:
Krueger AM. ESTIMATION OF DISCRETIZATION ERROR FOR THREE DIMENSIONAL CFD SIMULATIONS USING A TAYLOR SERIES MODIFIED EQUATION ANALYSIS. [Internet] [Masters thesis]. Texas A&M University; 2017. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/1969.1/169608.
Council of Science Editors:
Krueger AM. ESTIMATION OF DISCRETIZATION ERROR FOR THREE DIMENSIONAL CFD SIMULATIONS USING A TAYLOR SERIES MODIFIED EQUATION ANALYSIS. [Masters Thesis]. Texas A&M University; 2017. Available from: http://hdl.handle.net/1969.1/169608
University of Waterloo
8.
Shi, Yidan.
Statistical Methods for Event History Data under Response Dependent Sampling and Incomplete Observation.
Degree: 2020, University of Waterloo
URL: http://hdl.handle.net/10012/16062
► This thesis discusses statistical problems in event history data analysis including survival analysis and multistate models. Research questions in this thesis are motivated by the…
(more)
▼ This thesis discusses statistical problems in event history data analysis including survival analysis and multistate models. Research questions in this thesis are motivated by the Nun Study, which contains longevity data and longitudinal follow-up of cognition functions in 678 religious sisters. Our research interests lie in modeling the survival pattern and the disease process for dementia. These data are subject to a process-dependent sampling scheme, and the homogeneous Markov assumption is violated when using a multistate model to fit the panel data for cognition. In this thesis, we formulated three statistical questions according to the aforementioned issues and propose approaches to deal with these problems.
Survival analysis is often subject to left-truncation when the data are collected within certain study windows. Naive methods ignoring the sampling conditions yield invalid estimates. Much work has been done to deal with the bias caused by left-truncation. However, discussion on the loss-in-efficiency is limited. In Chapter 2, we proposed a method in which auxiliary information is borrowed to improve the efficiency in estimation. The auxiliary information includes summary-level statistics from a previous study on the same cohort and census data for a comparable population. The likelihood and score functions are developed. A Monte Carlo approximation is proposed to deal with the difficulty in obtaining tractable forms of the score and information functions. The method is illustrated by both simulation and real data application to the Nun Study.
Continuous-time Markov models are widely used for analyzing longitudinal data on the disease progression over time due to the great convenience for computing the probability transition matrices and the likelihood functions. However, in practice, the Markov assumption does not always hold. Most of the existing methods relax the Markov assumption while losing the advantage of that assumption in the calculation of transition probabilities. In Chapter 3, we consider the case where the violation of the Markov property is due to multiple underlying types of disease. We propose a mixture hidden Markov model where the underlying process is characterized by a mixture of multiple time-homogeneous Markov chains, one for each disease type, while the observation process contains states corresponding to the common symptomatic stages of these diseases. The method can be applied to modeling the disease process of Alzheimer's disease and other types of dementia. In the Nun Study, autopsies were conducted on some of the deceased participants so that one can know whether these individuals have Alzheimer's pathology in their brains. Our method can incorporate these partially observed pathology data as disease type indicators to improve the efficiency in estimation. The predictions for the overall prevalence and type-specific prevalence for dementia are calculated based on the proposed method. The performance of the proposed methods is also evaluated via simulation studies.
…
Subjects/Keywords: survival analysis; multistate model; left truncation; hidden Markov model; auxiliary information
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APA ·
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APA (6th Edition):
Shi, Y. (2020). Statistical Methods for Event History Data under Response Dependent Sampling and Incomplete Observation. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/16062
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Shi, Yidan. “Statistical Methods for Event History Data under Response Dependent Sampling and Incomplete Observation.” 2020. Thesis, University of Waterloo. Accessed January 24, 2021.
http://hdl.handle.net/10012/16062.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Shi, Yidan. “Statistical Methods for Event History Data under Response Dependent Sampling and Incomplete Observation.” 2020. Web. 24 Jan 2021.
Vancouver:
Shi Y. Statistical Methods for Event History Data under Response Dependent Sampling and Incomplete Observation. [Internet] [Thesis]. University of Waterloo; 2020. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/10012/16062.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Shi Y. Statistical Methods for Event History Data under Response Dependent Sampling and Incomplete Observation. [Thesis]. University of Waterloo; 2020. Available from: http://hdl.handle.net/10012/16062
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of California – San Diego
9.
Hou, Jue.
Modern Statistical Methods for Complex Survival Data.
Degree: Mathematics, 2019, University of California – San Diego
URL: http://www.escholarship.org/uc/item/2qj8m7vs
► With the booming of big complex data, various Statistical methods and Data Science techniques have been developed to retrieve valuable information from them.The progress is…
(more)
▼ With the booming of big complex data, various Statistical methods and Data Science techniques have been developed to retrieve valuable information from them.The progress is slower with survival data due to the additional difficulty from censoring and truncation. Except for a few straightforward extensions, most modern learning methods have been absent in survival analysis for years since their invention. The theory on the survival version of those methods also falls further behind. There is a strong demand on computational efficient and theoretical reliable methods for big complex data withtime-to-event outcomesin various Health related fields where immense resource has been poured into. This thesis is devoted to incorporating censoring and truncation to state-of-art Statistical methodology and theory, to promote the evolution of survival analysis and support Medical research with up-to-date tools. In Chapter 1, I study the mixture cure-rate model with left truncation and right-censoring. We propose a Nonparametric Maximum Likelihood Estimation (NPMLE) approach to effectively handle the truncation issue. We adopt an efficient and stable EM algorithm. We are able to give a closed form variance estimator giving rise to valid inference. In Chapter 2, I study the estimation and inference for the Fine-Gray competing risks model with high-dimensional covariates. We develop confidence intervals based on a one-step bias-correction to an initial regularized estimator. We lay down a methodological and theoretical framework for the one-step bias-corrected estimator with the partial likelihood. In Chapter 3, I study the inference on treatment effect with censored time-to-event outcome while adjusting for high-dimensional covariates. We propose an orthogonal score method to construct honest confidence intervals for the treatment effect. With a slight modification, we obtain a doubly robust estimator extremely tolerant to both estimation inconsistency and volatility. All the methods in aforementioned chapters are tested through extensive numerical experiments and applied on real data with authentic medical interests.
Subjects/Keywords: Mathematics; Statistics; Average treatment effect; High-dimensional data; Inference; Left-truncation
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APA (6th Edition):
Hou, J. (2019). Modern Statistical Methods for Complex Survival Data. (Thesis). University of California – San Diego. Retrieved from http://www.escholarship.org/uc/item/2qj8m7vs
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Hou, Jue. “Modern Statistical Methods for Complex Survival Data.” 2019. Thesis, University of California – San Diego. Accessed January 24, 2021.
http://www.escholarship.org/uc/item/2qj8m7vs.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Hou, Jue. “Modern Statistical Methods for Complex Survival Data.” 2019. Web. 24 Jan 2021.
Vancouver:
Hou J. Modern Statistical Methods for Complex Survival Data. [Internet] [Thesis]. University of California – San Diego; 2019. [cited 2021 Jan 24].
Available from: http://www.escholarship.org/uc/item/2qj8m7vs.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Hou J. Modern Statistical Methods for Complex Survival Data. [Thesis]. University of California – San Diego; 2019. Available from: http://www.escholarship.org/uc/item/2qj8m7vs
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Adelaide
10.
Otumawu-Apreku, Kofi.
Matters of management, sustainability, and efficiency: essays in fisheries.
Degree: 2013, University of Adelaide
URL: http://hdl.handle.net/2440/83828
► This thesis addresses three main issues in fisheries management: monitoring and enforcement; profit efficiency; and factors determining profit efficiency. The overall objective is to provide…
(more)
▼ This thesis addresses three main issues in fisheries management: monitoring and enforcement; profit efficiency; and factors determining profit efficiency. The overall objective is to provide broad theoretical and empirical analysis of fisheries management issues that seek to address sustainability and efficiency questions in the industry. The first issue investigated is whether monitoring and enforcement, as management policy instruments, can lower illegal harvesting and therefore preserve fish stocks. Using a game theoretic approach the strategic interaction between management and fishers, in the presence of illegal, unreported, and unregulated (IUU), is examined. Results of the analysis show that equilibrium compliance strategies of fishers affect stocks over time. It is further observed that increasing the cost of engaging in illegal activities, through punishment, may be sound economic policy. The second issue examined is efficiency in the South Australian Rock Lobster Fishery. To do this a new approach, in the context of fisheries, is used to overcome the small sample sizes and negative profit challenges inherent in fisheries. Specifically, the Nerlovian and Directional Distance Function methods are used to decompose profits of the fisheries into technical and allocative efficiencies. In addition, the meta-frontier efficiency technique is used to compare the Northern and Southern Zones, the two fisheries in the South Australian Rock Lobster Fishery. Results show that profit inefficiency in this fishery can be largely attributed to allocative inefficiency. Further, it is observed that there is significant variability between efficiency levels in the Northern and Southern Zones. The final issue considered is the natural question of what factors, besides technical and allocative inefficiency, may possibly explain profit inefficiencies in the South Australian Rock Lobster Fishery. To answer this question we investigate the effects of incorporating a fixed input on equilibrium profits and biomass. We first set up a theoretical model with an input that is fixed in the short-run (vessel size) but that can be used with a variable input at sub-optimal capacity. We use this model to get predictions for the impact on profits of exogenous changes in biomass, output price and vessel size. These give us interesting theoretical insights into why it is important to incorporate fixed inputs into profit analysis. We then conduct an empirical investigation to gain an understanding of the effects of these non-discretionary factors on profit efficiency. In particular, we apply a truncated regression with bootstrap methodology to data on individual firm profit efficiency from the South Australian Rock Lobster Fishery. We find empirical support for our predictions that increased biomass and smaller vessel length are associated with higher profits. An additional empirical result is that individual quota management is positively associated with profit efficiency.
Advisors/Committee Members: McWhinnie, Stephanie Faye (advisor), Kvasov, Dmitriy (advisor), Findlay, Christopher Charles (advisor), School of Economics (school).
Subjects/Keywords: violation; compliance; game-theoretic efficiency; Nerlovian; truncation; bootstrap
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APA (6th Edition):
Otumawu-Apreku, K. (2013). Matters of management, sustainability, and efficiency: essays in fisheries. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/83828
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Otumawu-Apreku, Kofi. “Matters of management, sustainability, and efficiency: essays in fisheries.” 2013. Thesis, University of Adelaide. Accessed January 24, 2021.
http://hdl.handle.net/2440/83828.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Otumawu-Apreku, Kofi. “Matters of management, sustainability, and efficiency: essays in fisheries.” 2013. Web. 24 Jan 2021.
Vancouver:
Otumawu-Apreku K. Matters of management, sustainability, and efficiency: essays in fisheries. [Internet] [Thesis]. University of Adelaide; 2013. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2440/83828.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Otumawu-Apreku K. Matters of management, sustainability, and efficiency: essays in fisheries. [Thesis]. University of Adelaide; 2013. Available from: http://hdl.handle.net/2440/83828
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Missouri University of Science and Technology
11.
Weerasinghe, Madhuka Hareena Lochana.
Balanced Truncation Model Reduction of Nonlinear Cable-Mass PDE System.
Degree: PhD, Mathematics, Missouri University of Science and Technology
URL: https://scholarsmine.mst.edu/doctoral_dissertations/2713
► We consider model order reduction of a cable-mass system modeled by a one dimensional wave equation with interior damping and dynamic boundary conditions. The…
(more)
▼ We consider model order reduction of a cable-mass system modeled by a one dimensional wave equation with interior damping and dynamic boundary conditions. The system is driven by a time dependent forcing input to a linear mass-spring system at the left boundary of the cable. A mass-spring model at the right end of the cable includes a nonlinear stiffening force. The goal of the model reduction is to produce a low order model that produces an accurate approximation to the displacement and velocity of the mass in the nonlinear mass-spring system at the right boundary. We believe the nonlinear cable-mass model considered here has not been explored elsewhere; therefore, we prove the well-posedness and exponential stability of the unforced linear and nonlinear models under certain conditions on the damping parameters, and then consider a balanced truncation method to generate the reduced order model (ROM) of the nonlinear input-output system. Little is understood about model reduction of nonlinear input-output systems. Therefore, we present detailed numerical experiments concerning the performance of the nonlinear ROM; we find that the ROM is accurate for many different combinations of model parameters. We also prove the well-posedness and exponential stability of other cable-mass problems with unbounded input and output operators, and numerically investigate the behavior of the ROMs for these systems
Subjects/Keywords: Balanced Truncation Method; Mathematics
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APA (6th Edition):
Weerasinghe, M. H. L. (n.d.). Balanced Truncation Model Reduction of Nonlinear Cable-Mass PDE System. (Doctoral Dissertation). Missouri University of Science and Technology. Retrieved from https://scholarsmine.mst.edu/doctoral_dissertations/2713
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Chicago Manual of Style (16th Edition):
Weerasinghe, Madhuka Hareena Lochana. “Balanced Truncation Model Reduction of Nonlinear Cable-Mass PDE System.” Doctoral Dissertation, Missouri University of Science and Technology. Accessed January 24, 2021.
https://scholarsmine.mst.edu/doctoral_dissertations/2713.
Note: this citation may be lacking information needed for this citation format:
No year of publication.
MLA Handbook (7th Edition):
Weerasinghe, Madhuka Hareena Lochana. “Balanced Truncation Model Reduction of Nonlinear Cable-Mass PDE System.” Web. 24 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Vancouver:
Weerasinghe MHL. Balanced Truncation Model Reduction of Nonlinear Cable-Mass PDE System. [Internet] [Doctoral dissertation]. Missouri University of Science and Technology; [cited 2021 Jan 24].
Available from: https://scholarsmine.mst.edu/doctoral_dissertations/2713.
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Council of Science Editors:
Weerasinghe MHL. Balanced Truncation Model Reduction of Nonlinear Cable-Mass PDE System. [Doctoral Dissertation]. Missouri University of Science and Technology; Available from: https://scholarsmine.mst.edu/doctoral_dissertations/2713
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Arizona State University
12.
Nagarajan, Venkatraman.
Numerical Simulation of Entrainment and Recirculating flow
at the Base of a Truncated Aerospike Nozzle with Supplementary Base
Flow.
Degree: Mechanical Engineering, 2017, Arizona State University
URL: http://repository.asu.edu/items/45499
► The aerospike nozzle belongs to the class of altitude compensating nozzles making it a strong candidate for Space Shuttle Main Engines. Owing to their higher…
(more)
▼ The aerospike nozzle belongs to the class of altitude
compensating nozzles making it a strong candidate for Space Shuttle
Main Engines. Owing to their higher efficiency compared to
conventional bell nozzles, the aerospike nozzles are being studied
extensively and are being used for many Single State to Orbit
(SSTO) designs. A rocket engine nozzle with altitude compensation,
such as the aerospike, consumes less fuel than a rocket engine with
a bell nozzle. Aerospike nozzles are huge and are often difficult
to construct and have to be truncated in order to make them
feasible for application in a rocket propulsion system.
Consequently, truncation of the aerospike leads to pressure loss
under the base, which in-turn decreases the overall thrust produced
by the rocket nozzle. To overcome this loss, a technique called
base bleed is implemented in which a secondary jet is made to flow
through the base of the truncated portion. This thesis uses dynamic
pressure contour plots to find out the ideal base bleed mass flow
rate to avoid base recirculation in 10 %, 20 % and 30 % truncated
aerospike nozzles.
Subjects/Keywords: Mechanical engineering; Aerospace engineering; Aerospike; Base Bleed; Plug nozzle; Truncation
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APA (6th Edition):
Nagarajan, V. (2017). Numerical Simulation of Entrainment and Recirculating flow
at the Base of a Truncated Aerospike Nozzle with Supplementary Base
Flow. (Masters Thesis). Arizona State University. Retrieved from http://repository.asu.edu/items/45499
Chicago Manual of Style (16th Edition):
Nagarajan, Venkatraman. “Numerical Simulation of Entrainment and Recirculating flow
at the Base of a Truncated Aerospike Nozzle with Supplementary Base
Flow.” 2017. Masters Thesis, Arizona State University. Accessed January 24, 2021.
http://repository.asu.edu/items/45499.
MLA Handbook (7th Edition):
Nagarajan, Venkatraman. “Numerical Simulation of Entrainment and Recirculating flow
at the Base of a Truncated Aerospike Nozzle with Supplementary Base
Flow.” 2017. Web. 24 Jan 2021.
Vancouver:
Nagarajan V. Numerical Simulation of Entrainment and Recirculating flow
at the Base of a Truncated Aerospike Nozzle with Supplementary Base
Flow. [Internet] [Masters thesis]. Arizona State University; 2017. [cited 2021 Jan 24].
Available from: http://repository.asu.edu/items/45499.
Council of Science Editors:
Nagarajan V. Numerical Simulation of Entrainment and Recirculating flow
at the Base of a Truncated Aerospike Nozzle with Supplementary Base
Flow. [Masters Thesis]. Arizona State University; 2017. Available from: http://repository.asu.edu/items/45499
13.
Jackson, Charles Wilson, V.
Truncation Error Based Mesh Adaptation and its Application to Multi-Mesh CFD.
Degree: PhD, Aerospace Engineering, 2019, Virginia Tech
URL: http://hdl.handle.net/10919/91890
► Computational fluid dynamics (CFD) describes a method of numerically solving equations that attempt to model the behavior of a fluid. As computers have become cheaper…
(more)
▼ Computational fluid dynamics (CFD) describes a method of numerically solving equations that attempt to model the behavior of a fluid. As computers have become cheaper and more powerful and the software has become more capable, CFD has become an integral part of the engineering process. One of the goals of the field is to be able to bring these higher fidelity simulations into the design loop earlier. Ideally, using CFD earlier in the design process would allow design engineers to create new innovative designs with less programmatic risk. Likewise, it is also becoming necessary to use these CFD tools later in the final design process to replace some physical experiments which can be expensive, unsafe, or infeasible to run. Both of these goals require the CFD codes to meet the accuracy requirements for the results as fast as possible. This work discusses several different methods for improving the accuracy of the simulations as well as ways of obtaining these more accurate results for the cheapest cost. In CFD, the governing equations modeling the flow behavior are solved on a computer. As a result, these continuous differential equations must be approximated as a system of discrete equations, so that they can be solved on a computer. These approximations result in discretization error, the difference between the exact solutions to the discrete and continuous equations, which is typically the largest type of numerical error in a CFD solution. The source of the discretization error is the
truncation error, which is composed of the terms left out of the approximations made when discretizing the continuous equations. Thus, if the
truncation error can be reduced, the discretization error in the solution should also be reduced. In this work, several different ways of reducing this
truncation error through mesh adaptation are discussed, including the use of optimization methods. These mesh optimization methods are compared to a more common way of performing adaptation, namely equidistribution. It is determined that equidistribution is able to reduce the discretization error by a similar amount while being significantly faster than mesh optimization. This work also presents a framework for making the adaptation process faster overall by performing the adaptation on a coarse mesh and then refining the mesh enough to meet the error tolerance for the application. This framework was the cheapest method investigated to meet a given error target. This work also introduces a new technique called multi-mesh CFD, which allows each equation (conservation of mass, momentum, energy, etc.) to be solved on a separate mesh. This allows each equation to be solved on a mesh that is specifically adapted for it, resulting in a more accurate solution. Here, it is shown that, for certain problems, the multi-mesh technique is able to obtain a solution with lower error than only using a single mesh. This work also shows that these more accurate results can be obtained in less time using multiple meshes than on a single mesh.
Advisors/Committee Members: Roy, Christopher John (committeechair), Canfield, Robert Arthur (committee member), Wang, Kevin Guanyuan (committee member), Borggaard, Jeffrey T. (committee member).
Subjects/Keywords: Computational Fluid Dynamics; Mesh Adaptation; Multi-Mesh CFD; Truncation Error
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APA ·
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APA (6th Edition):
Jackson, Charles Wilson, V. (2019). Truncation Error Based Mesh Adaptation and its Application to Multi-Mesh CFD. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/91890
Chicago Manual of Style (16th Edition):
Jackson, Charles Wilson, V. “Truncation Error Based Mesh Adaptation and its Application to Multi-Mesh CFD.” 2019. Doctoral Dissertation, Virginia Tech. Accessed January 24, 2021.
http://hdl.handle.net/10919/91890.
MLA Handbook (7th Edition):
Jackson, Charles Wilson, V. “Truncation Error Based Mesh Adaptation and its Application to Multi-Mesh CFD.” 2019. Web. 24 Jan 2021.
Vancouver:
Jackson, Charles Wilson V. Truncation Error Based Mesh Adaptation and its Application to Multi-Mesh CFD. [Internet] [Doctoral dissertation]. Virginia Tech; 2019. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/10919/91890.
Council of Science Editors:
Jackson, Charles Wilson V. Truncation Error Based Mesh Adaptation and its Application to Multi-Mesh CFD. [Doctoral Dissertation]. Virginia Tech; 2019. Available from: http://hdl.handle.net/10919/91890
University of Illinois – Urbana-Champaign
14.
Zarkevich, Nikolai Andreevich.
First-Principles Prediction of Thermodynamics and Ordering In Metallic Alloys.
Degree: PhD, University of Illinois at Urbana-Champaign, 2003, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/34849
Subjects/Keywords: Thermodynamics; metallic; cluster; truncation
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APA (6th Edition):
Zarkevich, N. A. (2003). First-Principles Prediction of Thermodynamics and Ordering In Metallic Alloys. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/34849
Chicago Manual of Style (16th Edition):
Zarkevich, Nikolai Andreevich. “First-Principles Prediction of Thermodynamics and Ordering In Metallic Alloys.” 2003. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 24, 2021.
http://hdl.handle.net/2142/34849.
MLA Handbook (7th Edition):
Zarkevich, Nikolai Andreevich. “First-Principles Prediction of Thermodynamics and Ordering In Metallic Alloys.” 2003. Web. 24 Jan 2021.
Vancouver:
Zarkevich NA. First-Principles Prediction of Thermodynamics and Ordering In Metallic Alloys. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2003. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2142/34849.
Council of Science Editors:
Zarkevich NA. First-Principles Prediction of Thermodynamics and Ordering In Metallic Alloys. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2003. Available from: http://hdl.handle.net/2142/34849
University of Illinois – Urbana-Champaign
15.
Camacho Ahumada, Santiago.
Truncation in differential Hahn fields.
Degree: PhD, Mathematics, 2018, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/100890
► Being closed under truncation for subsets of generalized series fields is a robust property in the sense that it is preserved under various algebraic and…
(more)
▼ Being closed under
truncation for subsets of generalized series fields is a robust property in the sense that it is preserved under various algebraic and transcendental extension procedures. Nevertheless, in Chapter 4 of this dissertation we show that generalized series fields with
truncation as an extra primitive yields undecidability in several settings. Our main results, however, concern the robustness of being
truncation closed in generalized series fields equipped with a derivation, and under extension procedures that involve this derivation. In the last chapter we study this in the ambient field T of logarithmic-exponential transseries. It leads there to a theorem saying that under a natural ``splitting'' condition the Liouville closure of a
truncation closed differential subfield of T is again
truncation closed.
Advisors/Committee Members: van den Dries, Lou (advisor), Hieronymi, Philipp (Committee Chair), Tserunyan, Anush (committee member), Walsberg, Erik (committee member).
Subjects/Keywords: Valued Fields; Transseries; Truncation; Differential Algebra; Hahn Fields
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APA (6th Edition):
Camacho Ahumada, S. (2018). Truncation in differential Hahn fields. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/100890
Chicago Manual of Style (16th Edition):
Camacho Ahumada, Santiago. “Truncation in differential Hahn fields.” 2018. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 24, 2021.
http://hdl.handle.net/2142/100890.
MLA Handbook (7th Edition):
Camacho Ahumada, Santiago. “Truncation in differential Hahn fields.” 2018. Web. 24 Jan 2021.
Vancouver:
Camacho Ahumada S. Truncation in differential Hahn fields. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2018. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2142/100890.
Council of Science Editors:
Camacho Ahumada S. Truncation in differential Hahn fields. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2018. Available from: http://hdl.handle.net/2142/100890
Texas Tech University
16.
Lee, Joohyun.
Characterization of the XTH gene family in cotton.
Degree: 2006, Texas Tech University
URL: http://hdl.handle.net/2346/16341
► Cotton is the single most important crop in Texas agriculture, reaching a value of 4 billion dollars per year. Cotton fiber is the major product…
(more)
▼ Cotton is the single most important crop in Texas agriculture, reaching a value of 4 billion dollars per year. Cotton fiber is the major product in cotton cultivation which is converted into economic revenue. Therefore, most research groups have focused on fiber development and improvement of fiber quality.
The xyloglucan endotransglucosylase/hydrolase gene family has a unique role in plant cell wall elongation and development during plant growth. It can cut and paste xyloglucan fragments into xyloglucan hemicellulose matrix in Type I plant cell wall, allowing cell wall extension and loosening while bearing tension for normal cell metabolism. XTH genes encode enzymes that may play a role in determining fiber length and other fiber qualities during cotton fiber development. Both the structures and functions of the XTH family have been well studied in Arabidopsis.
In this research the cotton XTH genes were cloned by using the sequence information of Arabidopsis XTHs. A cotton boll cDNA library and a cotton genomic BAC library were screened and used for cotton XTH gene cloning. The clones of cotton XTHs were classified to three distinctive groups based on their 3ŒUTR sequences. The three groups were denoted as GhXTH-G1, G2, and G3. The sequences of abnormal transcripts of GhXTH-G1 showed transcription termination in the middle of introns, producing shortened forms of mRNAs. In addition, two GhXTH-G1 genes were analyzed and assigned to A and D sub genomes. Real time quantitative RT-PCR was used to study tissue and development specific patterns of XTH gene expression. GhXTH-G3 appears to be the most important cotton XTHs in cotton fiber development. Also, hormone treatment results indicated that brassinolide (BL), gibberellin (GA3), naphthalene acetic acid (NAA) induced GhXTH expression in developing cotton fiber.
Advisors/Committee Members: Allen, Randy D. (Committee Chair), Auld, Dick L. (committee member), Zhang, Hong (committee member), Shi, Huazhong (committee member), Wright, Robert J. (committee member).
Subjects/Keywords: Gene expression; Transcription; Truncation
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to Zotero / EndNote / Reference
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APA (6th Edition):
Lee, J. (2006). Characterization of the XTH gene family in cotton. (Thesis). Texas Tech University. Retrieved from http://hdl.handle.net/2346/16341
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Lee, Joohyun. “Characterization of the XTH gene family in cotton.” 2006. Thesis, Texas Tech University. Accessed January 24, 2021.
http://hdl.handle.net/2346/16341.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Lee, Joohyun. “Characterization of the XTH gene family in cotton.” 2006. Web. 24 Jan 2021.
Vancouver:
Lee J. Characterization of the XTH gene family in cotton. [Internet] [Thesis]. Texas Tech University; 2006. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2346/16341.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Lee J. Characterization of the XTH gene family in cotton. [Thesis]. Texas Tech University; 2006. Available from: http://hdl.handle.net/2346/16341
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Kansas State University
17.
Crumer, Angela.
Investigating
the effects of common analytical techniques on reaction time
data.
Degree: PhD, Department of Psychological
Sciences, 2019, Kansas State University
URL: http://hdl.handle.net/2097/40196
► The heavy right skew of reaction time data creates challenges for analyses. Common analytical techniques may require a set of assumptions that are not found…
(more)
▼ The heavy right skew of reaction time data creates
challenges for analyses. Common analytical techniques may require a
set of assumptions that are not found in this type of data. Some of
the effects are known while others are not. The current study uses
Monte Carlo simulation to assess the effects of ignoring
distributional assumptions, aggregation, transformation, and
truncation on reaction time data. The effects of these current
practices were compared to fitting a generalized linear model. Each
analysis was simulated to obtain false alarm and hit rates. From
these values, the discriminability and criterion values from signal
detection theory were calculated. Parameter estimates were also
obtained and compared to the theoretical values from the simulation
to produce estimates of parameter bias and accuracy. While fitting
a generalized linear model had the highest discriminability and
unbiased criterion, it was not very different from ignoring
distributional assumptions and aggregating the data. Transforming
the data using a log transformation resulted in biased and
inaccurate parameter estimates and had the lowest discriminability.
Truncating the data inflated the error and resulted in poor signal
detection and poor parameter estimation.
Advisors/Committee Members: Michael Young.
Subjects/Keywords: Reaction
times; Generalized
linear model;
Truncation;
Transformation;
Gamma
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APA (6th Edition):
Crumer, A. (2019). Investigating
the effects of common analytical techniques on reaction time
data. (Doctoral Dissertation). Kansas State University. Retrieved from http://hdl.handle.net/2097/40196
Chicago Manual of Style (16th Edition):
Crumer, Angela. “Investigating
the effects of common analytical techniques on reaction time
data.” 2019. Doctoral Dissertation, Kansas State University. Accessed January 24, 2021.
http://hdl.handle.net/2097/40196.
MLA Handbook (7th Edition):
Crumer, Angela. “Investigating
the effects of common analytical techniques on reaction time
data.” 2019. Web. 24 Jan 2021.
Vancouver:
Crumer A. Investigating
the effects of common analytical techniques on reaction time
data. [Internet] [Doctoral dissertation]. Kansas State University; 2019. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2097/40196.
Council of Science Editors:
Crumer A. Investigating
the effects of common analytical techniques on reaction time
data. [Doctoral Dissertation]. Kansas State University; 2019. Available from: http://hdl.handle.net/2097/40196
Louisiana State University
18.
Ghazizadeh, Sara.
A study on the first-passage reliability problem and its application in earthquake engineering.
Degree: MSCE, Civil and Environmental Engineering, 2011, Louisiana State University
URL: etd-11102011-130607
;
https://digitalcommons.lsu.edu/gradschool_theses/992
► The research presented in this thesis focuses on analytical approximations for the time-variant first-passage failure probability (FPFP) of linear elastic models of structural systems subjected…
(more)
▼ The research presented in this thesis focuses on analytical approximations for the time-variant first-passage failure probability (FPFP) of linear elastic models of structural systems subjected to stochastic excitations. The FPFP is defined as the probability that a response quantity of an engineering system subjected to a dynamic stochastic loading outcrosses a specified threshold within a given exposure time. The FPFP is an important and useful quantity for many structural engineering applications. The classical first-passage reliability problem is studied for linear elastic single-degree-of-freedom (SDOF) and multi-degrees-of-freedom (MDOF) systems subjected to stationary and nonstationary Gaussian excitations. The absolute and relative accuracy of several analytical approximations available in the literature (i.e., the Poisson’s (P), classical Vanmarcke’s (cVM), and modified Vanmarcke’s (mVM) approximations) are studied through an extensive parametric study for SDOF systems. In addition, a new analytical approximation for the FPFP of linear SDOF systems is developed. The new proposed approximation is verified by comparing its analytical estimates of the failure probability with the corresponding results obtained using existing analytical approximations and the importance sampling using elementary events (ISEE) method for a wide range of oscillator properties and different types of input excitations. It is found that the newly developed analytical approximation provides estimates of the time-variant FPFP of SDOF systems that are significantly more accurate than the estimates obtained using the P, cVM, and mVM approximations. Real-valued and complex-valued modal analysis with modal truncation is used to study the time-variant FPFP of MDOF subjected to stationary and nonstationary stochastic excitations. The absolute and relative accuracy of the P, cVM, and mVM approximations as well as of the newly developed approximation are studied for a select number of case studies. It is found that the newly proposed analytical approximation cannot be directly extended to the computation of the FPFP of MDOF systems, while the mVM approximation appears to be more accurate than the other existing analytical approximations.
Subjects/Keywords: First-passage Failure Probability; Stochastic Dynamics; Modal Truncation; Pounding Problem
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APA (6th Edition):
Ghazizadeh, S. (2011). A study on the first-passage reliability problem and its application in earthquake engineering. (Masters Thesis). Louisiana State University. Retrieved from etd-11102011-130607 ; https://digitalcommons.lsu.edu/gradschool_theses/992
Chicago Manual of Style (16th Edition):
Ghazizadeh, Sara. “A study on the first-passage reliability problem and its application in earthquake engineering.” 2011. Masters Thesis, Louisiana State University. Accessed January 24, 2021.
etd-11102011-130607 ; https://digitalcommons.lsu.edu/gradschool_theses/992.
MLA Handbook (7th Edition):
Ghazizadeh, Sara. “A study on the first-passage reliability problem and its application in earthquake engineering.” 2011. Web. 24 Jan 2021.
Vancouver:
Ghazizadeh S. A study on the first-passage reliability problem and its application in earthquake engineering. [Internet] [Masters thesis]. Louisiana State University; 2011. [cited 2021 Jan 24].
Available from: etd-11102011-130607 ; https://digitalcommons.lsu.edu/gradschool_theses/992.
Council of Science Editors:
Ghazizadeh S. A study on the first-passage reliability problem and its application in earthquake engineering. [Masters Thesis]. Louisiana State University; 2011. Available from: etd-11102011-130607 ; https://digitalcommons.lsu.edu/gradschool_theses/992
University of Adelaide
19.
Guscott, Jake Callum.
Reliable Statistical Methods and their Applications for Testing Incomplete Multidisciplinary Data.
Degree: 2018, University of Adelaide
URL: http://hdl.handle.net/2440/127169
► Recently, left-truncated distributions have proved to be of use in modelling a range of phenomena in fields as diverse as finance, insurance, medicine, earthquake prediction…
(more)
▼ Recently, left-truncated distributions have proved to be of use in modelling a range of phenomena in fields as diverse as finance, insurance, medicine, earthquake prediction and wind power. In this thesis, we present a comprehensive analysis of the left-truncated Weibull, loglogistic, lognormal and Pareto distributions in cases where the scale, shape or both parameters are unlmown and estimated from the data with the maximum likelihood estimator. We define criteria which ensure that the maximum likelihood equations have a unique solution. We determine the critical values of the Kolmogorov-Smirnov, Kuiper, Cramer-von Mises and Anderson-Darling goodness-of-fit tests when the parameters are unknown for all of the left-truncated distributions via quantile analysis. In this work, these critical values are coupled with a rigorous point estimation and uncertainty analysis, and compared to the critical values of the complete (untruncated) distributions in the literature. We find strong agreement between our results and the most recent additions to the literature. Analytically, we provide evidence that the critical values are parameter independent for all of the left-truncated distributions and goodness-of-fit tests. This result is verified by determining the critical values via Monte Carlo simulations for a range of parameter values. We find that the critical values are dependent upon sample size and
truncation level (as percentage of the complete distribution), and determine suitable models to describe this behaviour. We modelled these critical values successfully for each of the three fitting scenarios (i)
truncation level dependence, (ii) sample size dependence and (iii)
truncation level and sample size dependence, which describes the behaviour for the critical values of all goodness-of-fit tests, left-truncated distributions and significance levels. The fact that one functional form describes the critical values for all different goodness-of-fit tests and distributions is a very useful and interesting result. The models are validated through an exhaustive power testing procedure, which also serves to compare the discriminatory power the four tests. We find the Anderson-Darling test has marginally better statistical power than the others in every situation and that the discrimantory power of all tests is weak for small sample sizes. We conclude the work by applying all these statistical methods to analysing the interarrival times of market orders on the London Stock Exchange for a range
truncation values and sample sizes. We find that the left-truncated Weibull distribution most accurately describes this data and that increasing the
truncation level significantly increases the pass rates.
Advisors/Committee Members: Kizilersu, Ayse (advisor), Thomas, A. W. (advisor), School of Physical Sciences (school).
Subjects/Keywords: truncation; statistics; goodness-of-fit; critical value; Monte Carlo
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APA (6th Edition):
Guscott, J. C. (2018). Reliable Statistical Methods and their Applications for Testing Incomplete Multidisciplinary Data. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/127169
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Guscott, Jake Callum. “Reliable Statistical Methods and their Applications for Testing Incomplete Multidisciplinary Data.” 2018. Thesis, University of Adelaide. Accessed January 24, 2021.
http://hdl.handle.net/2440/127169.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Guscott, Jake Callum. “Reliable Statistical Methods and their Applications for Testing Incomplete Multidisciplinary Data.” 2018. Web. 24 Jan 2021.
Vancouver:
Guscott JC. Reliable Statistical Methods and their Applications for Testing Incomplete Multidisciplinary Data. [Internet] [Thesis]. University of Adelaide; 2018. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2440/127169.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Guscott JC. Reliable Statistical Methods and their Applications for Testing Incomplete Multidisciplinary Data. [Thesis]. University of Adelaide; 2018. Available from: http://hdl.handle.net/2440/127169
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Georgia State University
20.
Jiang, Yong.
Estimation of Hazard Function for Right Truncated Data.
Degree: MS, Mathematics and Statistics, 2011, Georgia State University
URL: https://scholarworks.gsu.edu/math_theses/94
► This thesis centers on nonparametric inferences of the cumulative hazard function of a right truncated variable. We present three variance estimators for the Nelson-Aalen…
(more)
▼ This thesis centers on nonparametric inferences of the cumulative hazard function of a right truncated variable. We present three variance estimators for the Nelson-Aalen estimator of the cumulative hazard function and conduct a simulation study to investigate their performances. A close match between the sampling standard deviation and the estimated standard error is observed when an estimated survival probability is not close to 1. However, the problem of poor tail performance exists due to the limitation of the proposed variance estimators. We further analyze an AIDS blood transfusion sample for which the disease latent time is right truncated. We compute three variance estimators, yielding three sets of confidence intervals. This work provides insights of two-sample tests for right truncated data in the future research.
Advisors/Committee Members: Xu Zhang, Jiawei Liu, Yuanhui Xiao.
Subjects/Keywords: Right truncation; Kaplan-Meier method; Cumulative hazard; Two-sample test; Mathematics
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APA (6th Edition):
Jiang, Y. (2011). Estimation of Hazard Function for Right Truncated Data. (Thesis). Georgia State University. Retrieved from https://scholarworks.gsu.edu/math_theses/94
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Jiang, Yong. “Estimation of Hazard Function for Right Truncated Data.” 2011. Thesis, Georgia State University. Accessed January 24, 2021.
https://scholarworks.gsu.edu/math_theses/94.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Jiang, Yong. “Estimation of Hazard Function for Right Truncated Data.” 2011. Web. 24 Jan 2021.
Vancouver:
Jiang Y. Estimation of Hazard Function for Right Truncated Data. [Internet] [Thesis]. Georgia State University; 2011. [cited 2021 Jan 24].
Available from: https://scholarworks.gsu.edu/math_theses/94.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Jiang Y. Estimation of Hazard Function for Right Truncated Data. [Thesis]. Georgia State University; 2011. Available from: https://scholarworks.gsu.edu/math_theses/94
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of New South Wales
21.
Lee, Geul.
Truncation error treatment for the model-free implied moment estimator.
Degree: Banking & Finance, 2015, University of New South Wales
URL: http://handle.unsw.edu.au/1959.4/55743
;
https://unsworks.unsw.edu.au/fapi/datastream/unsworks:38981/SOURCE02?view=true
► This thesis investigates the impact of truncation, that is, the complete unavailability of significantly deep-out-of-the-money option price quotes, on the implied moment estimators of Bakshi…
(more)
▼ This thesis investigates the impact of
truncation, that is, the complete unavailability of significantly deep-out-of-the-money option price quotes, on the implied moment estimators of Bakshi et al. (2003) and suggests a new
truncation treatment method that makes
truncation error, or estimation bias due to
truncation, less volatile. Although previous studies have already suggested two
truncation error reduction methods for model-free implied moment estimation, these methods may not be able to effectively reduce
truncation error when they are used with the implied skewness or kurtosis estimators, which rely more heavily on deep-out-of-the-money option prices. Hence, we first test whether the two existing methods, specifically, the linear extrapolation method of Jiang and Tian (2005) and the domain symmetrisation method of Dennis and Mayhew (2002), can reduce
truncation error effectively even when they are used in conjunction with the two higher moment estimators. The test results show that the
truncation error reduction effect may be incomplete for both methods when they are used for implied skewness or kurtosis estimation. Given this result, we further investigate the relationship between
truncation level and
truncation error size, and then propose an alternative method of
truncation error treatment, namely, domain stabilisation, based on the relationship identified. The tests on the effectiveness of domain stabilisation reveal that although this method increases the mean size of the
truncation error, it also makes the size less volatile across different observations. This result implies that when our new method is employed,
truncation has less impact on cross-sectional comparison and on tracking the time-series dynamics of implied moments.
Advisors/Committee Members: Yang, Li, Banking & Finance, Australian School of Business, UNSW.
Subjects/Keywords: Skewness; Truncation error; Implied risk-neutral density; Kurtosis
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APA ·
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MLA ·
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CSE |
Export
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Manager
APA (6th Edition):
Lee, G. (2015). Truncation error treatment for the model-free implied moment estimator. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/55743 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:38981/SOURCE02?view=true
Chicago Manual of Style (16th Edition):
Lee, Geul. “Truncation error treatment for the model-free implied moment estimator.” 2015. Doctoral Dissertation, University of New South Wales. Accessed January 24, 2021.
http://handle.unsw.edu.au/1959.4/55743 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:38981/SOURCE02?view=true.
MLA Handbook (7th Edition):
Lee, Geul. “Truncation error treatment for the model-free implied moment estimator.” 2015. Web. 24 Jan 2021.
Vancouver:
Lee G. Truncation error treatment for the model-free implied moment estimator. [Internet] [Doctoral dissertation]. University of New South Wales; 2015. [cited 2021 Jan 24].
Available from: http://handle.unsw.edu.au/1959.4/55743 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:38981/SOURCE02?view=true.
Council of Science Editors:
Lee G. Truncation error treatment for the model-free implied moment estimator. [Doctoral Dissertation]. University of New South Wales; 2015. Available from: http://handle.unsw.edu.au/1959.4/55743 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:38981/SOURCE02?view=true
University of New South Wales
22.
Brown, Stefanie.
Analysis and minimisation of aliasing and truncation errors in the extraction of soundfields using spherical microphone arrays.
Degree: Electrical Engineering & Telecommunications, 2017, University of New South Wales
URL: http://handle.unsw.edu.au/1959.4/59104
;
https://unsworks.unsw.edu.au/fapi/datastream/unsworks:48464/SOURCE02?view=true
► The spherical harmonic (SH) framework is a powerful representation that can be used to describe to a 3D soundfield. It decomposes waves propagating through space…
(more)
▼ The spherical harmonic (SH) framework is a powerful representation that can be used to describe to a 3D soundfield. It decomposes waves propagating through space into a sum of infinitely many SH functions, a set of orthonormal basis functions over the sphere, and a set of source-dependent soundfield coefficients. The coefficients encode spatial information about the source and a wave propagation model. 3D soundfields can be captured or recorded using microphone arrays, manipulated or modified to enhance or reduce contributions from certain sources/locations, and reproduced using loudspeaker arrays to a degree of accuracy dependent on the array geometry. Other uses of the representation include SH beamforming, source localisation and isolation, and acoustic holography. This thesis focuses on the processes of coefficient extraction and some aspects of soundfield manipulation. Traditional extraction methods seek to gain a representation of all sources within the soundfield to a greater or lesser degree of accuracy. This thesis attempts to extract only the contributions from certain sources, spatially filtering the soundfield. The extraction process (involving discrete spatial sampling) introduces errors into the SH representation, in particular those of
truncation error (TE) from using only a finite number of coefficients to reproduce a soundfield and spatial aliasing (SA) errors in the extracted coefficients. This thesis derives several closed form solutions for the TE (excluding SA) under various soundfield conditions, and shows the connection between the plane and spherical wave cases. It also investigates the patterns of SA caused by the regularised inverse (RI) and orthonormal extraction (OE) methods and observes the combined effects of SA and TE for a particular spherical microphone array. This thesis proposes a spatial Wiener filter (SWF) that makes use of infinite spatial order prior models of the propagation model, source power and location to reduce SA errors and to reduce the contribution of unwanted sources to the coefficients. The RI and OE methods are analysed in the same manner and the SWF is shown to be superior at reducing SA. The SWF is then extended to a finite spatial order case. These methods are compared under various spatial scenarios and show the benefit of the SWF and eliminating an unwanted source, using the proposed measures of total mean square SA error and mean combined
truncation and SA error.
Advisors/Committee Members: Sen, Deep, Qualcomm, Taubman, David, Electrical Engineering & Telecommunications, Faculty of Engineering, UNSW, Sethu, Vidhyasaharan, Electrical Engineering & Telecommunications, Faculty of Engineering, UNSW.
Subjects/Keywords: Truncation error; Spherical microphone array; Spatial aliasing; spatial Wiener filter
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APA ·
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CSE |
Export
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Manager
APA (6th Edition):
Brown, S. (2017). Analysis and minimisation of aliasing and truncation errors in the extraction of soundfields using spherical microphone arrays. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/59104 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:48464/SOURCE02?view=true
Chicago Manual of Style (16th Edition):
Brown, Stefanie. “Analysis and minimisation of aliasing and truncation errors in the extraction of soundfields using spherical microphone arrays.” 2017. Doctoral Dissertation, University of New South Wales. Accessed January 24, 2021.
http://handle.unsw.edu.au/1959.4/59104 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:48464/SOURCE02?view=true.
MLA Handbook (7th Edition):
Brown, Stefanie. “Analysis and minimisation of aliasing and truncation errors in the extraction of soundfields using spherical microphone arrays.” 2017. Web. 24 Jan 2021.
Vancouver:
Brown S. Analysis and minimisation of aliasing and truncation errors in the extraction of soundfields using spherical microphone arrays. [Internet] [Doctoral dissertation]. University of New South Wales; 2017. [cited 2021 Jan 24].
Available from: http://handle.unsw.edu.au/1959.4/59104 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:48464/SOURCE02?view=true.
Council of Science Editors:
Brown S. Analysis and minimisation of aliasing and truncation errors in the extraction of soundfields using spherical microphone arrays. [Doctoral Dissertation]. University of New South Wales; 2017. Available from: http://handle.unsw.edu.au/1959.4/59104 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:48464/SOURCE02?view=true
University of Dayton
23.
Kordik, Andrew Michael.
Hardware Implementation of Post-Compression Rate-Distortion
Optimization for EBCOT in JPEG2000.
Degree: MS(M.S.), Electrical Engineering, 2011, University of Dayton
URL: http://rave.ohiolink.edu/etdc/view?acc_num=dayton1313791202
► As digital imaging sensors increase in size and capability, new ways to efficiently store/transmit the data they generate must be examined. JPEG2000 is the…
(more)
▼ As digital imaging sensors increase in size
and capability, new ways to efficiently store/transmit the data
they generate must be examined. JPEG2000 is the latest image
compression standard from the Joint Photographic Experts Group
which improves over earlier standards in its ability to compress
images while maintaining image quality. However,
with the compression gain advantage over other image compression
standard comes an additional computational cost. The JPEG2000
compressor is, substantially computationally complex than its
predecessor, JPEG [12]. There are 2 basic
procedures for irreversible rate reduction of JPEG2000 compressed
imagery: quantization, and post-compression rate-distortion
optimization (PCRD- Opt). Quantization is the method of reducing
the dynamic range of transformed image data prior to coding.
Quantization is a computationally simple method for data reduction,
but lacks in control of the compressed file size and is sub-optimal
in terms of image quality. PCRD-Opt, however, gives the user
precise control of the output file size, and provides compressed
imagery of the highest quality, per output bitrate
[11]. This thesis is an embedded development of
the PCRD-Opt algorithm, integrated into an FPGA-based JPEG2000
compression engine used for real-time compression of large-scale
imagery. The embedded PCRD-Opt method provides imagery with a 2dB
increase in quality over quantization on average, with a modest
increase in complexity with an FPGA chip utilization increase of
11% in ALUTs and 15% increase in Memory ALUTs per Tier I
encoder.
Advisors/Committee Members: Balster, Eric (Advisor).
Subjects/Keywords: Computer Engineering; FPGA; JPEG2000; PCRD-opt; Optimal Truncation
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APA ·
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MLA ·
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Export
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Manager
APA (6th Edition):
Kordik, A. M. (2011). Hardware Implementation of Post-Compression Rate-Distortion
Optimization for EBCOT in JPEG2000. (Masters Thesis). University of Dayton. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=dayton1313791202
Chicago Manual of Style (16th Edition):
Kordik, Andrew Michael. “Hardware Implementation of Post-Compression Rate-Distortion
Optimization for EBCOT in JPEG2000.” 2011. Masters Thesis, University of Dayton. Accessed January 24, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=dayton1313791202.
MLA Handbook (7th Edition):
Kordik, Andrew Michael. “Hardware Implementation of Post-Compression Rate-Distortion
Optimization for EBCOT in JPEG2000.” 2011. Web. 24 Jan 2021.
Vancouver:
Kordik AM. Hardware Implementation of Post-Compression Rate-Distortion
Optimization for EBCOT in JPEG2000. [Internet] [Masters thesis]. University of Dayton; 2011. [cited 2021 Jan 24].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=dayton1313791202.
Council of Science Editors:
Kordik AM. Hardware Implementation of Post-Compression Rate-Distortion
Optimization for EBCOT in JPEG2000. [Masters Thesis]. University of Dayton; 2011. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=dayton1313791202
Universiteit Utrecht
24.
Puijvelde, S.P. van.
Morphodynamics of De Slufter.
Degree: 2010, Universiteit Utrecht
URL: http://dspace.library.uu.nl:8080/handle/1874/45076
► De Slufter is a small tidal inlet located on Texel, The Netherlands. From 8 September to 17 October 2008, a field work was carried out…
(more)
▼ De Slufter is a small tidal inlet located on Texel, The Netherlands. From 8 September to 17 October 2008, a field work was carried out in De Slufter measuring the morphological development of the mouth area and water levels and flow velocities in the main channel. The aim of this report is to study the interaction between basin morphology and the hydrodynamics of the system and its implications for the long term stability and evolution of De Slufter. In a stable inlet there is a balance between the import of sediment during the flood phase and the export of sediment during the ebb phase, by which the inlet remains connected to the sea. The tide is however deformed when it enters the inlet. The most important mechanisms causing this deformation include tidal
truncation and a hypsometry effect. Tidal deformation results in duration asymmetries, causing differences in peak flood- and ebb-velocities. A deformed velocity signal leads to a net sediment transport. This determines the stability of the inlet. Not much is known about the stability of small tidal inlets. This is related to the distinct morphology of De Slufter, with its small amount of intertidal flats and large surface area between 1.1-1.5 m +NAP.
Analyzing yearly aerial photographs, a channel migration cycle of 3-7 years is observed in the mouth area. Migration occurs from the southwest to the northeast and the channel curvature increases at the end of the cycle. The cycle ends with channel relocation by man. During the initial calm weather period of the field campaign, no channel migration was observed. During the two storm events a channel migration was observed in the most seaward section of the channel. The narrowest section of the channel migrated approximately 10 metres. The curvature of the channel also increased and the channel slightly changed its orientation. Most channel profiles reveal a storm-induced widening of the channel. This resulted in an increase of the cross-sectional area up to 22.1% in the seaward section of the channel. This enlargement was accompanied by slightly lower peak ebb- and flood-velocities. During fair weather conditions in the final phase of the field work, equilibrium was partly restored by decreasing the cross section again. Migration of the channel is possibly related to the combined effect of wave-impact, the longshore current and a circulation pattern developing during storms. This circulation imports water over the beach flat, due to submergence and overwash, and exports it again through the channel. The accretion on the beach flat and retreat of the beach face as a result of storm-conditions are probably related to the same circulation pattern. The storm events enlarged inlet cross sections.
During fair weather conditions a large tidal deformation was measured in De Slufter. The amplitudes of M2 and M4 and the M4/M2-ratio all decreased compared to the North Sea. A phase relationship (2M2-M4)sea of 270-360 degrees was measured, indicating a longer ebb than flood duration. Compared to the North Sea (where the tide is…
Advisors/Committee Members: Vegt, M. van der, Hoekstra, P..
Subjects/Keywords: Geowetenschappen; slufter, inlet, texel, netherlands, morphodynamics, stability, hypsometry, truncation, tidal asymmetry, channel migration, tidal deformation
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APA ·
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MLA ·
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Export
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APA (6th Edition):
Puijvelde, S. P. v. (2010). Morphodynamics of De Slufter. (Masters Thesis). Universiteit Utrecht. Retrieved from http://dspace.library.uu.nl:8080/handle/1874/45076
Chicago Manual of Style (16th Edition):
Puijvelde, S P van. “Morphodynamics of De Slufter.” 2010. Masters Thesis, Universiteit Utrecht. Accessed January 24, 2021.
http://dspace.library.uu.nl:8080/handle/1874/45076.
MLA Handbook (7th Edition):
Puijvelde, S P van. “Morphodynamics of De Slufter.” 2010. Web. 24 Jan 2021.
Vancouver:
Puijvelde SPv. Morphodynamics of De Slufter. [Internet] [Masters thesis]. Universiteit Utrecht; 2010. [cited 2021 Jan 24].
Available from: http://dspace.library.uu.nl:8080/handle/1874/45076.
Council of Science Editors:
Puijvelde SPv. Morphodynamics of De Slufter. [Masters Thesis]. Universiteit Utrecht; 2010. Available from: http://dspace.library.uu.nl:8080/handle/1874/45076
Johannes Gutenberg Universität Mainz
25.
Bull-Herenu, Kester.
Ontogenetic studies on the determination of the apical meristem in racemose inflorescences.
Degree: 2010, Johannes Gutenberg Universität Mainz
URL: http://ubm.opus.hbz-nrw.de/volltexte/2010/2363/
► This thesis presents a comparative developmental study of inflorescences and focuses on the production of the terminal flower (TF). Morphometric attributes of inflorescence meristems (IM)…
(more)
▼ This thesis presents a comparative developmental study of inflorescences and focuses on the production of the terminal flower (TF). Morphometric attributes of inflorescence meristems (IM) were obtained throughout the ontogeny of inflorescence buds with the aim of describing possible spatial constraints that could explain the failure in developing the TF. The study exposes the inflorescence ontogeny of 20 species from five families of the Eudicots (Berberidaceae, Papaveraceae-Fumarioideae, Rosaceae, Campanulaceae and Apiaceae) in which 745 buds of open (i.e. without TF) and closed (i.e. with TF) inflorescences were observed under the scanning electron microscope.rnThe study shows that TFs appear on IMs which are 2,75 (se = 0,38) times larger than the youngest lateral reproductive primordium. The shape of these IMs is characterized by a leaf arc (phyllotactic attribute) of 91,84° (se = 7,32) and a meristematic elevation of 27,93° (se = 5,42). IMs of open inflorescences show a significant lower relative surface, averaging 1,09 (se=0,26) times the youngest primordium size, which suggests their incapacity for producing TFs. The relative lower size of open IMs is either a condition throughout the complete ontogeny (‘open I’) or a result from the drastic reduction of the meristematic surface after flower segregation (‘open II’). rnIt is concluded that a suitable bulge configuration of the IM is a prerequisite for TF formation. Observations in the TF-facultative species Daucus carota support this view, as the absence of the TF in certain umbellets is correlated with a reduction of their IM dimensions. A review of literature regarding histological development of IMs and genetic regulation of inflorescences suggests that in ‘open I’ inflorescences, the histological composition and molecular activity at the tip of the IM could impede the TF differentiation. On the other side, in ‘open II’ inflorescences, the small final IM bulge could represent a spatial constraint that hinders the differentiation of the TF. The existence of two distinct kinds of ontogenies of open inflorescences suggests two ways in which the loss of the TF could have occurred in the course of evolution.rn
Die Dissertation beinhaltet eine vergleichende Studie zur Entwicklung von Blütenständen, wobei der Schwerpunkt auf der Bildung bzw. dem Fehlen von Endblüten (EB) liegt. Morphometrische Veränderungen, die während der Ontogenie der Blütenstandsknospen am Infloreszenzmeristem (IM) auftreten, wurden erstmals ermittelt und quantifiziert, um eventuelle räumliche Zwänge, die das Ausfallen der EB erklären könnten, zu beschreiben. Die Studie umfasst die Infloreszenzontogenie von 20 Arten aus fünf Familien der Eudicotyledonae (Berberidaceae, Papaveraceae-Fumarioideae, Rosaceae, Campanulaceae and Apiaceae) mit offenen (ohne EB) und geschlossenen (mit EB) Blütenständen. Sie basiert auf der Analyse von 745 Infloreszenzknospen unter dem Rasterelektronmikroskop.rnDie Ergebnisse zeigen, dass sich Endblüten nur an Infloreszenzmeristemen entwickeln, die 2,75 (se =…
Subjects/Keywords: Infloreszenz; Endblüte; Entwicklung; Trunkation; REM; inflorescence; terminal flower; development; truncation; SEM; Botanical sciences
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APA (6th Edition):
Bull-Herenu, K. (2010). Ontogenetic studies on the determination of the apical meristem in racemose inflorescences. (Doctoral Dissertation). Johannes Gutenberg Universität Mainz. Retrieved from http://ubm.opus.hbz-nrw.de/volltexte/2010/2363/
Chicago Manual of Style (16th Edition):
Bull-Herenu, Kester. “Ontogenetic studies on the determination of the apical meristem in racemose inflorescences.” 2010. Doctoral Dissertation, Johannes Gutenberg Universität Mainz. Accessed January 24, 2021.
http://ubm.opus.hbz-nrw.de/volltexte/2010/2363/.
MLA Handbook (7th Edition):
Bull-Herenu, Kester. “Ontogenetic studies on the determination of the apical meristem in racemose inflorescences.” 2010. Web. 24 Jan 2021.
Vancouver:
Bull-Herenu K. Ontogenetic studies on the determination of the apical meristem in racemose inflorescences. [Internet] [Doctoral dissertation]. Johannes Gutenberg Universität Mainz; 2010. [cited 2021 Jan 24].
Available from: http://ubm.opus.hbz-nrw.de/volltexte/2010/2363/.
Council of Science Editors:
Bull-Herenu K. Ontogenetic studies on the determination of the apical meristem in racemose inflorescences. [Doctoral Dissertation]. Johannes Gutenberg Universität Mainz; 2010. Available from: http://ubm.opus.hbz-nrw.de/volltexte/2010/2363/
Carnegie Mellon University
26.
Wei, Xiaodong.
Highly Localized Refinement Using Truncation Mechanism on Unstructured Quadrilateral and Hexahedral Meshes.
Degree: 2017, Carnegie Mellon University
URL: http://repository.cmu.edu/dissertations/1097
► To tightly integrate Computer Aided Design (CAD) and Finite Element Analysis (FEA), isogeometric analysis was proposed by employing the same basis functions for geometric representation…
(more)
▼ To tightly integrate Computer Aided Design (CAD) and Finite Element Analysis (FEA), isogeometric analysis was proposed by employing the same basis functions for geometric representation in analysis, aiming to eliminate the time-consuming mesh generation in traditional FEA. Non-Uniform Rational B-Spline (NURBS), as the current industry standard in CAD community, was the first candidate utilized in isogeometric analysis. However, due to the global tensor-product nature of NURBS, it does not support local refinement and arbitrary topology. Local refinement is essential in both local editing (from perspective of design) and adaptive analysis (from perspective of analysis), which are known for high efficiency in terms of computation cost. Arbitrary topology, on the other hand, is unavoidable in complex geometries. In this dissertation, we develop various methods to address highly localized refinement that supports arbitrary topology in the context of isogeometric analysis. The proposed methods are suitable for both geometric design and engineering analysis, with necessary properties carefully investigated. We present Truncated Hierarchical Catmull-Clark Subdivision (THCCS), which generalizes truncated hierarchical B-splines to control grids of arbitrary topology. By coupling truncated hierarchical B-splines and Catmull-Clark subdivision, THCCS takes advantages of both methods and hence it possesses several nice properties suitable for geometric design and adaptive analysis. THCCS basis functions satisfy partition of unity, are linearly independent, and are locally refinable. THCCS also preserves geometry during adaptive h-refinement and thus inherits the surface continuity of Catmull-Clark subdivision, namely C2-continuous everywhere except at the local region surrounding extraordinary nodes, where the surface continuity is C1. However, the local refinement of THCCS imposes a strong restraint that in each refinement step, at least the two-ring neighborhood of a control point needs to be refined. To improve its refinement locality, an extended version of THCCS, namely extended Truncated Hierarchical Catmull-Clark Subdivision, is proposed. Based on the Stam’s method, we first build a set of basis functions over arbitrary quadrilateral meshes and apply them to THCCS. Then, a new basis-function-insertion scheme is developed with the aid of the truncation mechanism, which refines one-ring neighborhood rather than two-ring neighborhood. Therefore, eTHCCS significantly improves the efficiency of local refinement compared with THCCS. Despite the flexibility for Catmull-Clark subdivision in handling extraordinary points, it is not compatible with the current CAD industry standard, i.e., NURBS. T-splines, on the other hand, as a superior alternative to NURBS, have no such issue. We present Truncated T-splines as a new type of T-splines suitable for both geometric design and analysis, supporting highly localized refinement. By introducing truncation mechanism into T-spline basis functions, truncated T-splines release the strong…
Subjects/Keywords: Local Refinement; Extraordinary Points; Truncation; Catmull-Clark Subdivision; T-splines; Volumetric Splines
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APA ·
Chicago ·
MLA ·
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CSE |
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APA (6th Edition):
Wei, X. (2017). Highly Localized Refinement Using Truncation Mechanism on Unstructured Quadrilateral and Hexahedral Meshes. (Thesis). Carnegie Mellon University. Retrieved from http://repository.cmu.edu/dissertations/1097
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Wei, Xiaodong. “Highly Localized Refinement Using Truncation Mechanism on Unstructured Quadrilateral and Hexahedral Meshes.” 2017. Thesis, Carnegie Mellon University. Accessed January 24, 2021.
http://repository.cmu.edu/dissertations/1097.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Wei, Xiaodong. “Highly Localized Refinement Using Truncation Mechanism on Unstructured Quadrilateral and Hexahedral Meshes.” 2017. Web. 24 Jan 2021.
Vancouver:
Wei X. Highly Localized Refinement Using Truncation Mechanism on Unstructured Quadrilateral and Hexahedral Meshes. [Internet] [Thesis]. Carnegie Mellon University; 2017. [cited 2021 Jan 24].
Available from: http://repository.cmu.edu/dissertations/1097.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Wei X. Highly Localized Refinement Using Truncation Mechanism on Unstructured Quadrilateral and Hexahedral Meshes. [Thesis]. Carnegie Mellon University; 2017. Available from: http://repository.cmu.edu/dissertations/1097
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Michigan
27.
Tse, SzeMan.
Gaussian approximations in the random truncation model.
Degree: PhD, Statistics, 1995, University of Michigan
URL: http://hdl.handle.net/2027.42/129657
► The dissertation deals with various issues of the random left truncation model, in which we observe bivariate data (Xi,Yi) only when Xi ≥ Yi, i=1,\..., n.…
(more)
▼ The dissertation deals with various issues of the random left
truncation model, in which we observe bivariate data (X
i,Y
i) only when X
i ≥ Y
i, i=1,\..., n. Denote the distribution function of the X
i by F and let F
n be its nonparametric maximum likelihood product-limit estimator. Part I of the dissertation develops strong approximations of the product-limit process √{n}[ F
n(t)-F(t)] on increasing sets by a sequence of copies of a Gaussian process with a convergence rate that on fixed sets reduces to n
-1/6 log n. The basis of the approximation is Borisov's extension of Komlos, Major and Tusnady's approximation theorem for the ordinary empirical process to higher dimensions. In our case, the appropriate dimension is two. Part II turns to the kernel estimator of the density function of X. Based on the results of Part I, under suitable choice of the bandwidth sequence, we obtain the exact rate of pointwise convergence (a law of the iterated logarithm), the exact rate of uniform convergence (a law of the logarithm), the asymptotic finite-dimensional distributions, and the extreme-value limiting distributions for maximal deviations. The covariance of the limiting Gaussian process in Part I and II involves the unknown distribution function F. This leads us to consider bootstrap constructions of nonparametric confidence bands for F. In Part III, we develop the bootstrap parallel to the asymptotic theory of the product-limit process. The results demonstrate the asymptotic validity of nonparametric bootstrap procedures in the random
truncation model. Some simulated examples will illustrate the procedure.
Advisors/Committee Members: Csorgo, Sandor (advisor).
Subjects/Keywords: Approximations; Convergence; Gaussian; Model; Random; Truncation
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APA ·
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APA (6th Edition):
Tse, S. (1995). Gaussian approximations in the random truncation model. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/129657
Chicago Manual of Style (16th Edition):
Tse, SzeMan. “Gaussian approximations in the random truncation model.” 1995. Doctoral Dissertation, University of Michigan. Accessed January 24, 2021.
http://hdl.handle.net/2027.42/129657.
MLA Handbook (7th Edition):
Tse, SzeMan. “Gaussian approximations in the random truncation model.” 1995. Web. 24 Jan 2021.
Vancouver:
Tse S. Gaussian approximations in the random truncation model. [Internet] [Doctoral dissertation]. University of Michigan; 1995. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/2027.42/129657.
Council of Science Editors:
Tse S. Gaussian approximations in the random truncation model. [Doctoral Dissertation]. University of Michigan; 1995. Available from: http://hdl.handle.net/2027.42/129657
Anna University
28.
Venkateswaran, N.
Discrete wavelet transform based Hybrid image coding
schemes for continuous tone images; -.
Degree: Information and Communication
Engineering, 2014, Anna University
URL: http://shodhganga.inflibnet.ac.in/handle/10603/27362
► The thesis aims to propose new hybrid algorithms for wavelet newlinebased image compression of continuous tone still images to achieve low bit newlinerates The algorithms…
(more)
▼ The thesis aims to propose new hybrid algorithms
for wavelet newlinebased image compression of continuous tone still
images to achieve low bit newlinerates The algorithms have been
proposed by combining Discrete Wavelet newlineTransform Absolute
Moment Block Truncation Coding Singular Value newlineDecomposition
and Clustering of data for the purpose of vector quantization
newlineThe proposed algorithms offer improved compression ratio The
proposed newlinemethods utilize the property of wavelet transform
in which most of the detail newlinesubband coefficients remain
quantized to zero Also a set of Daubechies newlinewavelet templates
are designed to be used with Cellular Neural Networks in
newlinehigh speed image compression applications newlineIn this
thesis two hybrid image compression algorithms that are
newlinebased on Absolute Moment Block Truncation Coder AMBTC and
DWT are newlineproposed The proposed method is very attractive due
to its reduced newlinecomputational complexity newline
newline
reference p.115-122
Advisors/Committee Members: Ramana Rao, Y V.
Subjects/Keywords: Absolute Moment Block Truncation; Cellular Neural Networks; Decomposition and Clustering; Discrete Wavelet Transform
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APA ·
Chicago ·
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CSE |
Export
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APA (6th Edition):
Venkateswaran, N. (2014). Discrete wavelet transform based Hybrid image coding
schemes for continuous tone images; -. (Thesis). Anna University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/27362
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Venkateswaran, N. “Discrete wavelet transform based Hybrid image coding
schemes for continuous tone images; -.” 2014. Thesis, Anna University. Accessed January 24, 2021.
http://shodhganga.inflibnet.ac.in/handle/10603/27362.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Venkateswaran, N. “Discrete wavelet transform based Hybrid image coding
schemes for continuous tone images; -.” 2014. Web. 24 Jan 2021.
Vancouver:
Venkateswaran N. Discrete wavelet transform based Hybrid image coding
schemes for continuous tone images; -. [Internet] [Thesis]. Anna University; 2014. [cited 2021 Jan 24].
Available from: http://shodhganga.inflibnet.ac.in/handle/10603/27362.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Venkateswaran N. Discrete wavelet transform based Hybrid image coding
schemes for continuous tone images; -. [Thesis]. Anna University; 2014. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/27362
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Universidade de Lisboa
29.
Costa, Filipa Alexandra Pina Barrento da Costa.
Evaluation of the D-Spect system: region centric acquisition and tracer kinetics.
Degree: 2012, Universidade de Lisboa
URL: http://www.rcaap.pt/detail.jsp?id=oai:repositorio.ul.pt:10451/8851
► Tese de mestrado integrado em Engenharia Biomédica e Biofísica, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2012
A tomografia de emissão de…
(more)
▼ Tese de mestrado integrado em Engenharia Biomédica e Biofísica, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2012
A tomografia de emissão de fotão único, usualmente conhecido por SPECT (do inglês single photon emission computed tomography), é uma técnica de medicina nuclear que permite diagnosticar doenças derivadas de alterações a nível fisiológico e celular. De forma a obter uma imagem SPECT, um radioisótopo é administrado ao paciente e a distribuição dos fotões emitidos é detectada de forma a criar uma imagem 3D. SPECT é cada vez mais utilizado para estudos cardíacos, no entanto o sistema ainda tem alguma limitações, e como tal novos sistemas de SPECT mais focalizados para exames ao coração foram surgindo. Um novo equipamento que foi criado em 2006, denominado D-SPECT, foi desenvolvido com o objectivo de criar imagens de perfusão de miocárdio com melhor qualidade de imagem, permitindo diagnósticos mais precisos. D-SPECT, ao contrário do sistema SPECT convencional, é constituído por 9 detectores montados verticalmente, criando uma configuração curva, adaptando-se ao tórax de um individuo. Para além da geometria inovadora, D-SPECT permite também a selecção manual de uma região de interesse (RI), permitindo “region centric aquisition” focada no coração. Consequentemente, o sistema pode ser programado de forma a calcular o padrão de scan de acordo com a RI definida, despendendo mais tempo nessa região e menos no restante campo de visão dos detectores. No final, imagens com mais sensibilidade, melhor resolução em energia e resolução espacial são obtidos. Para além disso o tempo de aquisição é reduzido bem como a dose recebida pelo paciente. O sistema SPECT é constituído por uma gantry que roda à volta do paciente, com o objectivo de adquirir numero suficiente de projecções para conseguir reconstruir correctamente uma imagem. A reconstrução tomografica pode ser realizada através de métodos analíticos e iterativos, sendo o último o método com mais vantagens. O D-SPECT utiliza um método iterativo especifico denominado OS-EM (ordered subsets expectation maximization), permitindo incorporar modelos probabilísticos de ruído Poisson e outra características do sistema de medicina nuclear previamente conhecidas. O sistema SPECT permite também adquirir exames ao longo do tempo, possibilitando estudos dinâmicos. Os estudos dinâmicos envolvem a obtenção de imagens em diferentes instantes, desde a injecção do radiofármaco, sendo identificado um pico de actividade nos ventrículos e aurículas, até esse valor baixar, mantendo-se praticamente constante em diferentes órgãos. Desta forma, a distribuição do radiofármaco ao longo do tempo pode ser obtida e estudada com o objectivo de serem criadas curvas de tecido-tempo (TACs do inglês time activity-curves). A elaboração destas curvas permitem retirar parâmetros essenciais para estudos quantitativo que dão informação sobre fluxo sanguíneo, permitindo detectar patologias. No entanto a aquisição dinâmica através do sistema SPECT tende a criar projecções…
Advisors/Committee Members: Almeida, Pedro Miguel Dinis de, 1968-, Hutton, Brian F..
Subjects/Keywords: Cardiac Spect; D-SPECT; ROI; Truncation; Extra-cardiac activity; Dynamic SPECT; Teses de mestrado - 2012
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APA ·
Chicago ·
MLA ·
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Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Costa, F. A. P. B. d. C. (2012). Evaluation of the D-Spect system: region centric acquisition and tracer kinetics. (Thesis). Universidade de Lisboa. Retrieved from http://www.rcaap.pt/detail.jsp?id=oai:repositorio.ul.pt:10451/8851
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Costa, Filipa Alexandra Pina Barrento da Costa. “Evaluation of the D-Spect system: region centric acquisition and tracer kinetics.” 2012. Thesis, Universidade de Lisboa. Accessed January 24, 2021.
http://www.rcaap.pt/detail.jsp?id=oai:repositorio.ul.pt:10451/8851.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Costa, Filipa Alexandra Pina Barrento da Costa. “Evaluation of the D-Spect system: region centric acquisition and tracer kinetics.” 2012. Web. 24 Jan 2021.
Vancouver:
Costa FAPBdC. Evaluation of the D-Spect system: region centric acquisition and tracer kinetics. [Internet] [Thesis]. Universidade de Lisboa; 2012. [cited 2021 Jan 24].
Available from: http://www.rcaap.pt/detail.jsp?id=oai:repositorio.ul.pt:10451/8851.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Costa FAPBdC. Evaluation of the D-Spect system: region centric acquisition and tracer kinetics. [Thesis]. Universidade de Lisboa; 2012. Available from: http://www.rcaap.pt/detail.jsp?id=oai:repositorio.ul.pt:10451/8851
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Australian National University
30.
Ding, Ni.
Submodularity and Its Applications in Wireless Communications
.
Degree: 2017, Australian National University
URL: http://hdl.handle.net/1885/124067
► This monograph studies the submodularity in wireless communications and how to use it to enhance or improve the design of the optimization algorithms. The work…
(more)
▼ This monograph studies the submodularity in wireless
communications and how to use it to enhance or improve the design
of the optimization algorithms. The work is done in three
different systems.
In a cross-layer adaptive modulation problem, we prove the
submodularity of the dynamic programming (DP), which contributes
to the monotonicity of the optimal transmission policy. The
monotonicity is utilized in a policy iteration algorithm to
relieve the curse of dimensionality of DP. In addition, we show
that the monotonic optimal policy can be determined by a
multivariate minimization problem, which can be solved by a
discrete simultaneous perturbation stochastic approximation
(DSPSA) algorithm. We show that the DSPSA is able to converge to
the optimal policy in real time.
For the adaptive modulation problem in a network-coded two-way
relay channel, a two-player game model is proposed. We prove the
supermodularity of this game, which ensures the existence of pure
strategy Nash equilibria (PSNEs). We apply the Cournot
tatonnement and show that it converges to the extremal, the
largest and smallest, PSNEs within a finite number of iterations.
We derive the sufficient conditions for the extremal PSNEs to be
symmetric and monotonic in the channel signal-to-noise (SNR)
ratio.
Based on the submodularity of the entropy function, we study the
communication for omniscience (CO) problem: how to let all users
obtain all the information in a multiple random source via
communications. In particular, we consider the minimum sum-rate
problem: how to attain omniscience by the minimum total number of
communications. The results cover both asymptotic and
non-asymptotic models where the transmission rates are real and
integral, respectively. We reveal the submodularity of the
minimum sum-rate problem and propose polynomial time algorithms
for solving it. We discuss the significance and applications of
the fundamental partition, the one that gives rise to the minimum
sum-rate in the asymptotic model. We also show how to achieve the
omniscience in a successive manner.
Subjects/Keywords: submodularity;
lattice;
L-convexity;
communication for omniscience;
monotone comparative statics;
Dilworth truncation
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Ding, N. (2017). Submodularity and Its Applications in Wireless Communications
. (Thesis). Australian National University. Retrieved from http://hdl.handle.net/1885/124067
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Ding, Ni. “Submodularity and Its Applications in Wireless Communications
.” 2017. Thesis, Australian National University. Accessed January 24, 2021.
http://hdl.handle.net/1885/124067.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Ding, Ni. “Submodularity and Its Applications in Wireless Communications
.” 2017. Web. 24 Jan 2021.
Vancouver:
Ding N. Submodularity and Its Applications in Wireless Communications
. [Internet] [Thesis]. Australian National University; 2017. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/1885/124067.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Ding N. Submodularity and Its Applications in Wireless Communications
. [Thesis]. Australian National University; 2017. Available from: http://hdl.handle.net/1885/124067
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
◁ [1] [2] [3] [4] [5] ▶
. 
Open Access Theses and Dissertations
