Dissertations / Theses on the topic 'Dimensional analysis'
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1
Wang, Tao. "Variable selection and dimension reduction in high-dimensional regression." HKBU Institutional Repository, 2013. http://repository.hkbu.edu.hk/etd_ra/1544.
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Aljarrah, Inad A. "Three Dimensional Face Recognition Using Two Dimensional Principal Component Analysis." Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1142453613.
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Long, Xianbin. "Dimensional analysis and partial evaluation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq23390.pdf.
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Hubble, Andrew. "Two-Dimensional Compressible Vortex Analysis." Thesis, Tufts University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1589459.
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With the introduction of bivelocity in 2004, new models for the prediction of Maxwellian, compressible micro-channel flows have recently been developed. This thesis utilizes a non-kinetic method to explore an analytic prediction of two-dimensional velocity profiles of steady and transient, unbounded, compressible vortex flows. This bivelocity hydrodynamic model is compared to the traditional analytical solutions of the Navier-Stokes Fourier (NSF), Boltzmann, and Burnett equations, as well as to Mandella's 1987 experiments in compressible vorticies, highlighting the stark contrasts between these models. While definitive convergence has yet to be obtained, the bivelocity approach has shown promise in resolving these issues. The importance of these bivelocity addition provides a clean explanation for the poor analytic correlations to experimental data previously attempted. While further investigation is required, bivelocity definitively improves upon the current models..
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Battey, Heather Suzanne. "Dimension reduction and automatic smoothing in high dimensional and functional data analysis." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609849.
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Kanneganti, Raghuveer. "CLASSIFICATION OF ONE-DIMENSIONAL AND TWO-DIMENSIONAL SIGNALS." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/dissertations/892.
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This dissertation focuses on the classification of one-dimensional and two-dimensional signals. The one-dimensional signal classification problem involves the classification of brain signals for identifying the emotional responses of human subjects under given drug conditions. A strategy is developed to accurately classify ERPs in order to identify human emotions based on brain reactivity to emotional, neutral, and cigarette-related stimuli in smokers. A multichannel spatio-temporal model is employed to overcome the curse of dimensionality that plagues the design of parametric multivariate classifiers for multi-channel ERPs. The strategy is tested on the ERPs of 156 smokers who participated in a smoking cessation program. One half of the subjects were given nicotine patches and the other half were given placebo patches. ERPs were collected from 29 channel in response to the presentation of the pictures with emotional (pleasant and unpleasant), neutral/boring, and cigarette-related content. It is shown that human emotions can be classified accurately and the results also show that smoking cessation causes a drop in the classification accuracies of emotions in the placebo group, but not in the nicotine patch group. Given that individual brain patterns were compared with group average brain patterns, the findings support the view that individuals tend to have similar brain reactions to different types of emotional stimuli. Overall, this new classification approach to identify differential brain responses to different emotional types could lead to new knowledge concerning brain mechanisms associated with emotions common to most or all people. This novel classification technique for identifying emotions in the present study suggests that smoking cessation without nicotine replacement results in poorer differentiation of brain responses to different emotional stimuli. Future, directions in this area would be to use these methods to assess individual differences in responses to emotional stimuli and to different drug treatments. Advantages of this and other brain-based assessment include temporal precision (e.g, 400-800 ms post stimulus), and the elimination of biases related to self-report measures. The two-dimensional signal classification problems include the detection of graphite in testing documents and the detection of fraudulent bubbles in test sheets. A strategy is developed to detect graphite responses in optical mark recognition (OMR) documents using inexpensive visible light scanners. The main challenge in the formulation of the strategy is that the detection should be invariant to the numerous background colors and artwork in typical optical mark recognition documents. A test document is modeled as a superposition of a graphite response image and a background image. The background image in turn is modeled as superposition of screening artwork, lines, and machine text components. A sequence of image processing operations and a pattern recognition algorithm are developed to estimate the graphite response image from a test document by systematically removing the components of the background image. The proposed strategy is tested on a wide range of scanned documents and it is shown that the estimated graphite response images are visually similar to those scanned by very expensive infra-red scanners currently employed for optical mark recognition. The robustness of the detection strategy is also demonstrated by testing a large number of simulated test documents. A procedure is also developed to autonomously determine if cheating has occurred by detecting the presence of aberrant responses in scanned OMR test books. The challenges introduced by the significant imbalance in the numbers of typical and aberrant bubbles were identified. The aberrant bubble detection problem is formulated as an outlier detection problem. A feature based outlier detection procedure in conjunction with a one-class SVM classifier is developed. A multi-criteria rank-of-rank-sum technique is introduced to rank and select a subset of features from a pool of candidate features. Using the data set of 11 individuals, it is shown that a detection accuracy of over 90% is possible. Experiments conducted on three real test books flagged for suspected cheating showed that the proposed strategy has the potential to be deployed in practice.
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Ruan, Lingyan. "Statistical analysis of high dimensional data." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37135.
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This century is surely the century of data (Donoho, 2000). Data analysis has been an emerging activity over the last few decades. High dimensional data is in particular more and more pervasive with the advance of massive data collection system, such as microarrays, satellite imagery, and financial data. However, analysis of high dimensional data is of challenge with the so called curse of dimensionality (Bellman 1961). This research dissertation presents several methodologies in the application of high dimensional data analysis.
The first part discusses a joint analysis of multiple microarray gene expressions. Microarray analysis dates back to Golub et al. (1999). It draws much attention after that. One common goal of microarray analysis is to determine which genes are differentially expressed. These genes behave significantly differently between groups of individuals. However, in microarray analysis, there are thousands of genes but few arrays (samples, individuals) and thus relatively low reproducibility remains. It is natural to consider joint analyses that could combine microarrays from different experiments effectively in order to achieve improved accuracy. In particular, we present a model-based approach for better identification of differentially expressed genes by incorporating data from different studies. The model can accommodate in a seamless fashion a wide range of studies including those performed at different platforms, and/or under different but overlapping biological conditions. Model-based inferences can be done in an empirical Bayes fashion. Because of the information sharing among studies, the joint analysis dramatically improves inferences based on individual analysis. Simulation studies and real data examples are presented to demonstrate the effectiveness of the proposed approach under a variety of complications that often arise in practice.
The second part is about covariance matrix estimation in high dimensional data. First, we propose a penalised likelihood estimator for high dimensional t-distribution. The student t-distribution is of increasing interest in mathematical finance, education and many other applications. However, the application in t-distribution is limited by the difficulty in the parameter estimation of the covariance matrix for high dimensional data. We show that by imposing LASSO penalty on the Cholesky factors of the covariance matrix, EM algorithm can efficiently compute the estimator and it performs much better than other popular estimators.
Secondly, we propose an estimator for high dimensional Gaussian mixture models. Finite Gaussian mixture models are widely used in statistics thanks to its great flexibility. However, parameter estimation for Gaussian mixture models with high dimensionality can be rather challenging because of the huge number of parameters that need to be estimated. For such purposes, we propose a penalized likelihood estimator to specifically address such difficulties. The LASSO penalty we impose on the inverse covariance matrices encourages sparsity on its entries and therefore helps reducing the dimensionality of the problem. We show that the proposed estimator can be efficiently computed via an Expectation-Maximization algorithm. To illustrate the practical merits of the proposed method, we consider its application in model-based clustering and mixture discriminant analysis. Numerical experiments with both simulated and real data show that the new method is a valuable tool in handling high dimensional data.
Finally, we present structured estimators for high dimensional Gaussian mixture models. The graphical representation of every cluster in Gaussian mixture models may have the same or similar structure, which is an important feature in many applications, such as image processing, speech recognition and gene network analysis. Failure to consider the sharing structure would deteriorate the estimation accuracy. To address such issues, we propose two structured estimators, hierarchical Lasso estimator and group Lasso estimator. An EM algorithm can be applied to conveniently solve the estimation problem. We show that when clusters share similar structures, the proposed estimator perform much better than the separate Lasso estimator.
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Shen, Xilin. "Multiscale analysis of high dimensional data." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3284443.
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Ferrecchia, Antonella. "Analysis of three-dimensional dynamic stall." Thesis, University of Glasgow, 2002. http://theses.gla.ac.uk/4429/.
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The work presented in this thesis attempts to provide a deeper understanding of the physical phenomena associated with the dynamic stall process on finite wing planforms. The work involves the analysis of data from the Glasgow University unsteady aerodynamics database that has been built up over a number of years through contributions from a range of researchers. Analysis focuses on two finite wing models; one a rectangular wing of aspect ratio three and the other with the same overall dimensions but with 60o swept tips. However, as most research to date has focused on nominally two-dimensional data, the results are referenced to measurements made on a nominally two-dimensional NACA 0015 aerofoil model. This is appropriate as this aerofoil was used as the wing section of both of the three-dimensional wing models. Flow visualisation images collected in a previous study also provide valuable information to supplement the pressure analysis. It is shown that, although the flow at the mid span sections of the finite wings exhibit many of the features of the two-dimensional case, there are some significant differences. In particular, the three-dimensional flow is dominated by the downwash from the wing tips. This causes the normal force response during pitching to lag the static normal force curve. This is in complete contrast to the two-dimensional case where the shed vorticity induces the opposite effect. The downwash also influences the incidence of lift stall but it does so in a manner that is dependent on the reduced pitch rate. Despite these effects, it is established that the flow behaviour in the mid-span region is almost two-dimensional prior to vortex inception. This provides an opportunity to examine the relationship between the generation of vorticity, or vorticity flux, in the leading edge region and the origins of the dynamic stall vortex at specific span locations in location. The vorticity flux distributions around the leading edges of the nominally two-dimensional NACA 0015 aerofoil and the two finite wings are then examined for pitching cases. On this basis a link is established between the peak vorticity flux and the dynamic stall vortex formation. This is confirmed by comparison of the vorticity flux measurements with a previous dynamic stall vortex detection method. The two methods are shown to five almost identical results in situations where the flow may be considered nominally two-dimensional. This suggests that monitoring vorticity flux may provide a practical method of dynamic stall vortex detection. In regions of the finite wings that exhibit strong three-dimensional flow effects, i.e. away from the mid-span, the peak vorticity flux is achieved after the dynamic stall vortex forms. This suggests that vortex formation is triggered by interference from adjacent sections of the wing. To examine this possibility, the vorticity flux is compared to a criterion used to detect the initial instability of the boundary layer at the leading edge. It is shown that the relationship between this criterion and the peak vorticity flux is the same along the span of the wing. This is a significant result as it demonstrates that, although the leading edge response determines the incidence of vortex onset near the mid-span, the formation of the vortex on sections of the wing closer to the tips occurs before the leading edge becomes critical. The implications of this for dynamic stall modelling of two-dimensional dynamic stall predictors with lifting line formulations will not capture this effect.
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Donaghy, Richard James. "Dimensional reduction of stress analysis models." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263368.
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Komanapalli, Golda Word. "Verifying influence diagrams using dimensional analysis." Thesis, London South Bank University, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606323.
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System Dynamics (SD) is an approach to modelling that has found wide application in systems modelling. Although originally rooted in the engineering discipline, SD models have been formulated for problems in diverse fields including management, health, education and the social sciences and has attracted interest from modellers with little mathematical or engineering training. Developing a valid model is of primary importance in the System Dynamics modelling process. To establish that a model produces the right behaviour for the right reasons, it is essential to ensure that the structure of the model represents the corresponding real world system. Amongst the verification procedures employed in the model building process, dimensional analysis is used to verify the syntactical correctness of the model’s equations. However, dimensional analysis is frequently not given the highest priority as a verification tool in the model building process especially among those less experienced in mathematical modelling or who lack confidence in the use of mathematics. Therefore, the potential lack of dimensional consistency within some Systems Dynamics model raises serious doubts about the validity of the model, the results generated and hence the policy decisions that follow. The aim of this research is to summarise the various problems related to validation and verification that can occur in the process of SD modelling and to suggest an alternative approach. Firstly, this research devises an algorithm, “TAID” (Tree Analysis of Influence Diagrams), which analyses influence diagrams and derives dimensionally correct equations. Secondly, a software tool “I, Model” is developed to demonstrate the utility of the algorithm. Finally the revised approach to SD modelling is evaluated to measure its impact on the learning and modelling experience of SD modellers. The outcomes of the small evaluation study indicate that the modellers preferred the TAID approach over the traditional SD modelling approach during the model implementation stage. The two principal benefits that this research can offer to the SD community are: firstly, a software tool based on this new approach that can ease the transition from a qualitative system model to a verified quantitative simulation model and thereby extend the benefits of quantitative SD modelling to a wider range of users; and, secondly, to improve the SD modelling experience of all users of SD methodology but especially for those modellers who have limited mathematical experience.
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Neate, Andrew. "A one dimensional analysis of singularities of the d-dimensional stochastic Burgers equation." Thesis, Swansea University, 2005. https://cronfa.swan.ac.uk/Record/cronfa42800.
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This thesis presents a one dimensional analysis of the singularities of the d- dimensional stochastic Burgers equation using the 'reduced action function'. In particular, we investigate the geometry of the caustic, the Maxwell set and the Hamilton-Jacobi level surfaces, and describe some turbulent phenomena. Chapter 1 begins by introducing the stochastic Burgers equation and its related Stratonovich heat equation. Some earlier geometric results of Davies, Truman and Zhao are presented together with the derivation of the reduced action function. In Chapter 2 we present a complete analysis of the caustic in terms of the derivatives of the reduced action function, which leads to a new method for identifying the singular (cool) parts of the caustic. Chapter 3 investigates the spontaneous formation of swallowtails on the caustic and Hamilton-Jacobi level surfaces. Using a circle of ideas due to Arnol'd, Cayley and Klein, we find necessary conditions for these swallowtail perestroikas and relate these conditions to the reduced action function. In Chapter 4 we find an explicit formula for the Maxwell set by considering the double points of the level surfaces in the two dimensional polynomial case. We extend this to higher dimensions using a double discriminant of the reduced action function and then consider the geometric properties of the Maxwell set in terms of the pre-Maxwell set. We conclude in Chapter 5 by using our earlier work to model turbulence in the Burgers fluid. We show that the number of cusps on the level surfaces can change infinitely rapidly causing 'real turbulence' and also that the number of swallowtails on the caustic can change infinitely rapidly causing 'complex turbulence'. These processes are both inherently stochastic in nature. We determine their intermittence in terms of the recurrent behaviour of two processes derived from the reduced action.
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Shin, Hyejin. "Infinite dimensional discrimination and classification." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5832.
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Modern data collection methods are now frequently returning observations that should
be viewed as the result of digitized recording or sampling from stochastic processes rather
than vectors of finite length. In spite of great demands, only a few classification methodologies
for such data have been suggested and supporting theory is quite limited. The focus of
this dissertation is on discrimination and classification in this infinite dimensional setting.
The methodology and theory we develop are based on the abstract canonical correlation
concept of Eubank and Hsing (2005), and motivated by the fact that Fisher's discriminant
analysis method is intimately tied to canonical correlation analysis. Specifically, we have
developed a theoretical framework for discrimination and classification of sample paths
from stochastic processes through use of the Loeve-Parzen isomorphism that connects a
second order process to the reproducing kernel Hilbert space generated by its covariance
kernel. This approach provides a seamless transition between the finite and infinite dimensional
settings and lends itself well to computation via smoothing and regularization. In
addition, we have developed a new computational procedure and illustrated it with simulated
data and Canadian weather data.
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Sleath, Leslie C. "The dimensional variation analysis of complex mechanical systems." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/13996.
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Dimensional variation analysis (DVA) is a computer based simulation process used to identify potential assembly process issues due the effects of component part and assembly variation during manufacture. The sponsoring company has over a number of years developed a DVA process to simulate the variation behaviour of a wide range of static mechanical systems. This project considers whether the current DVA process used by the sponsoring company is suitable for the simulation of complex kinematic systems. The project, which consists of three case studies, identifies several issues that became apparent with the current DVA process when applied to three types of complex kinematic systems. The project goes on to develop solutions to the issues raised in the case studies in the form of new or enhanced methods of information acquisition, simulation modelling and the interpretation and presentation of the simulation output Development of these methods has enabled the sponsoring company to expand the range of system types that can be successfully simulated and significantly enhances the information flow between the DVA process and the wider product development process.
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Karlsson, David. "Analysis of Three-Dimensional Cracks in Submodels." Thesis, Linköping University, Department of Management and Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8105.
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A common technique to evaluate load paths in complex structures is to perform FE-calculations with relative large elements. This procedure gives no information regarding stress concentrations at e.g. holes or radius but this phenomenon can later on be investigated in details with local individual submodels. Displacements is taken from the global model and used to analyse stress concentrations and crack driving parameters in the submodel.
Today, the crack controlling stress intensity factors are in general cases obtained from handbook solutions of elementary cases. This method requires engineering judgements in a conservative manner and one way to improve the solution is to model the crack in its correct surroundings in a local three-dimensional submodel.
This master thesis is focused on the development of an automated support for analysing three-dimensional cracks in submodels. The results from a global Nastran model can be imported to Trinitas and used for a more accurate stress and fatigue life analysis in a local model. Here a three-dimensional crack tip subdomain can be generated inside an eight point brick volume. The crack tip subdomain is specially designed and adjusted for accurate determination of stress intensity factors along the crack front. For example, all points are adjusted with respect to the brick volume and the crack size, triangular wedge elements are applied around the crack tip, the midpoints for these elements are moved to quarter points and the crack front is curved. The crack tip subdomain is validated against several reference cases and shows sufficiently good results with respect to the stress intensity factor.
Finally, the automated crack tip subdomain generation is applied to a geometrically complex part of a main wing carry-through bulkhead of a fighter aircraft in order to show the applicability of the procedure in an industrial environment.
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Inan, Ozgur. "Three Dimensional Fracture Analysis Of Fgm Coatings." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605299/index.pdf.
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The main objective of this study is to model the three dimensional surface cracking problem in Functionally Graded Material (FGM) coatings bonded to homogeneous substrates. The FGM coating is assumed to be a (ZrO2) &ndash(Ti-6Al-4V) layer. Homogeneous ceramic, metal &ndash
rich, ceramic &ndash
rich and linear variation material compositions are considered in the analyses. The surface crack is assumed to have a semi &ndash
circular crack front profile. The surface crack problem in the FGM coating &ndash
substrate system is examined under mechanical and transient thermal loading. Structural and thermal problems are modeled using three dimensional finite elements. Strain singularity around the crack front is simulated using collapsed 20 &ndash
node quarter &ndash
point brick elements. Three - dimensional displacement correlation technique is utilized to extract the stress intensity factors. The main results of the study are the stress intensity factors around the crack front for FGM coating - substrate structures subjected to uniform tension, bending, fixed &ndash
grip tension, three point bending and transient thermal loading.
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Ficici, Ferhan. "Three Dimensional Fracture Analysis Of Fillet Welds." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608351/index.pdf.
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The aim of this study is to model three dimensional surface crack problems in fillet welds. It is assumed that weld material has the same material properties with the sheet metals. The surface crack is considered to occur at two regionsone at the weld root and the other at the weld toe. The surface crack is assumed to have a semi &ndash
elliptical crack front profile. The surface crack problem is analyzed under mechanical loading and the models are built up by three dimensional finite elements. Around the crack front, strain singularity is taken into account by using degenerated 20 &ndash
node quarter &ndash
point solid elements. The main results of this work are the stress intensity factors around the crack front for the test specimen model subjected to axial and bending loads.
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Akgul, Gorkem. "Three Dimensional Fracture Analysis Of Orthotropic Materials." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614334/index.pdf.
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The main objective of this study is to examine the three-dimensional surface crack problems in orthotropic materials subjected to mechanical or thermal loading. The cracks are modeled and embedded in the orthotropic material by considering semielliptical crack front geometry. In the model special elements are embedded in the crack front region, in this way it is possible to include crack tip singular fields along the crack front. Three-dimensional finite element analyses are conducted to obtain mode I stress intensity factors. The stress intensity factor is calculated by using the displacement correlation technique. In the analysis, collapsed 20-node iso-parametric elements are utilized to simulate strain singularity around the semi-elliptical crack front. The surface crack problem is analyzed under both mechanical and thermal stresses. In the case of mechanical loading, uniform tension and fixed grip tension loading cases are applied on the model. In thermal analysis, thermal boundary conditions are defined. Comparisons of the results generated to those available in
the literature verify the developed techniques.
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Norris, Ryan. "Two-Dimensional Phononic Crystal Simulation and Analysis." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2792.
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This thesis presents the design of a two-dimensional phononic band gap crystal simulator, and phononic crystal analysis. Phononic crystals and their application to microwave acoustic filters are studied. Wave mechanics is introduced. A two-dimensional phononic crystal simulator is developed. Simulator operation is validated through comparison with published data. Design parameters for phononic crystal band gap engineering are outlined. Digital signal processing and wave mechanics are utilized to analyze fractal and circular inclusion based phononic crystals. Topics for further study are given.
Phononic crystal band structure is found to be sensitive to inclusion boundary geometry. Fractal inclusion based crystals provide multiple pass band characteristics. The evolution of a fractal inclusion in a phononic crystal may cause band gap widening and the formation of new band gaps. Circular inclusion based phononic crystals have piecewise-linear phase characteristics and quality factors up to 600.
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Janzen, Walter F. "Cable stayed bridges : nonlinear elastic dimensional analysis." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28388.
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Cable stayed bridges are the state of the art in long span bridges. Developments in cable response analysis and computer hardware and software have allowed engineers to design and build many cable stayed bridges. Bridges of many different configurations with longer and longer spans are being built. With the long spans and high axial loads in the deck, the stability of cable stayed bridges becomes a growing concern. Current analysis procedures use a parabolic approximation to the true catenary response of cables, which is quite accurate for tight cables; however, for near instability conditions with the accompanying large deflections and consequently loose cables, a catenary model is called for. Herein, a study is conducted on the elastic stability of cable stayed bridges utilizing a true catenary model of cable response. A dimensional analysis of cable stayed bridge stability is undertaken as well as deck maximum deflection and moment under service load conditions.
A computer program written by this author is the analysis tool used in this work. The program is given the acronym ULA which stands for Ultimate Load Analysis. ULA is a nonlinear plane frame program with catenary cable elements and an interactive graphics interface. The dimensional analysis is carried out by comparing the computer model of a cable stayed bridge to the theoretical model of a beam on an elastic foundation.
Two preliminary simplified cable stayed bridge backspan models are studied first in order to develop the dimensionless ratios that are applicable to the bridge response and to gain an insight into the cable stayed bridge behaviour. The final model is that of an entire cable stayed bridge. Because of the multitude of parameters governing cable stayed bridge behaviour it is not possible to describe all cable stayed bridges. Instead, the dimensionless behaviour of a standard model is examined and the sensitivity of this standard to various parameter variations is given in the form of dimensionless charts. Finally, a preliminary design and analysis aid is developed from the dimensionless charts and is then applied to two existing bridge designs.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Barnes, Jonathan D. "3-dimensional stress analysis of superheater headers." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/26841.
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Elizondo, Michael A. "Dimensional analysis of structural steel beam design." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28127.
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Clark, Jerome Adrian. "Dimensional analysis of the Quantified Judgement Model." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/26997.
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Approved for public release; distribution is unlimited.Quantitative analysis, specifically in this thesis which studies the Quantified Judgment Model (QJM), has been used consistently as a method of analyzing ground combat. If the QJM model is to be used as a basis for making' important ground combat decisions, then its internal mathematical consistency and military soundness must be fIrmly established. A universal requirement is that any model be both reasonable and valid, in which case the model itself must be able to withstand careful scrutiny. In the case of the QJM, a dimensional analysis to ensure ,.' mathematical consistency of the variables and submodels is one test of the reasonableness of the model. Dimensional analysis tests are applied in this thesis to examine the validity of the QJM. We also perfonn some analyses to determine how sensitive the outcomes predicted by the mooel are to the values of several of the coefficients appearing in its submodels. The fInal chapter presents our conclusions and recommendations for further investigation of the QJM.
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Ho, K. H. L. "Probabilistic scene analysis of two dimensional images." Thesis, University of Bristol, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303747.
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Hueting, Moos. "Cross-dimensional analysis for improved scene understanding." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10040861/.
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Visual data have taken up an increasingly large role in our society. Most people have instant access to a high quality camera in their pockets, and we are taking more pictures than ever before. Meanwhile, through the advent of better software and hardware, the prevalence of 3D data is also rapidly expanding, and demand for data and analysis methods is burgeoning in a wide range of industries. The amount of information about the world implicitly contained in this stream of data is staggering. However, as these images and models are created in uncontrolled circumstances, the extraction of any structured information from the unstructured pixels and vertices is highly non-trivial. To aid this process, we note that the 2D and 3D data modalities are similar in content, but intrinsically different in form. Exploiting their complementary nature, we can investigate certain problems in a cross-dimensional fashion - for example, where 2D lacks expressiveness, 3D can supplement it; where 3D lacks quality, 2D can provide it. In this thesis, we explore three analysis tasks with this insight as our point of departure. First, we show that by considering the tasks of 2D and 3D retrieval jointly we can improve performance of 3D retrieval while simultaneously enabling interesting new ways of exploring 2D retrieval results. Second, we discuss a compact representation of indoor scenes called a "scene map", which represents the objects in a scene using a top-down map of object locations. We propose a method for automatically extracting such scene maps from single 2D images using a database of 3D models for training. Finally, we seek to convert single 2D images to full 3D scenes using a database of 3D models as input. Occlusion is handled by modelling object context explicitly, allowing us to identify and pose objects that would otherwise be too occluded to make inferences about. For all three tasks, we show the utility of our cross-dimensional insight by evaluating each method extensively and showing favourable performance over baseline methods.
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Block, Philippe (Philippe Camille Vincent). "Thrust Network Analysis : exploring three-dimensional equilibrium." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/49539.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Architecture, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 145-153).
This dissertation presents Thrust Network Analysis, a new methodology for generating compression-only vaulted surfaces and networks. The method finds possible funicular solutions under gravitational loading within a defined envelope. Using projective geometry, duality theory and linear optimization, it provides a graphical and intuitive method, adopting the same advantages of techniques such as graphic statics, but offering a viable extension to fully three-dimensional problems. The proposed method is applicable for the analysis of vaulted historical structures, specifically in unreinforced masonry, as well as the design of new vaulted structures. This dissertation introduces the method and shows examples of applications in both fields. Thrust Network Analysis, masonry, historic structures, compression-only structures, limit analysis, equilibrium analysis, funicular design, form-finding, structural optimization, Gothic vaults, reciprocal diagrams.
by Philippe Block.
Ph.D.
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Sardouk, Khalil. "Analysis of dimensional control in 3D printing." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12146.
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Duranza, Sonia. "Three-dimensional image analysis using confocal microscopy." FIU Digital Commons, 1998. http://digitalcommons.fiu.edu/etd/3106.
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This thesis introduces imaging algorithms for three-dimensional data analysis and classification using confocal microscopy. The third dimension, depth information, is provided through the optical sectioning property of the confocal microscope. The theme of this thesis is to develop imaging techniques that extend beyond the traditional two-dimensional (2-D) spatial coordinate system into an augmented three-dimensional (3-D) world where analysis, interpretation, and the eventual classification of data is greatly enhanced. In the development of the proposed 3-D algorithms, three main objectives were sought: (1) establish proper 3-D mathematical extensions and practical implementations of 2-D standard formulations; (2) ensure that the process of classification overcomes the burden imposed by dependence in size and orientation through applications of the principal component transform and the log-spherical plot; and (3) address such issues as memory management and accelerated processing to reach the final objective of data recognition and classification effectively.
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Sun, Yizhi. "Statistical Analysis of Structured High-dimensional Data." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/97505.
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High-dimensional data such as multi-modal neuroimaging data and large-scale networks carry excessive amount of information, and can be used to test various scientific hypotheses or discover important patterns in complicated systems. While considerable efforts have been made to analyze high-dimensional data, existing approaches often rely on simple summaries which could miss important information, and many challenges on modeling complex structures in data remain unaddressed. In this proposal, we focus on analyzing structured high-dimensional data, including functional data with important local regions and network data with community structures.
The first part of this dissertation concerns the detection of ``important'' regions in functional data. We propose a novel Bayesian approach that enables region selection in the functional data regression framework. The selection of regions is achieved through encouraging sparse estimation of the regression coefficient, where nonzero regions correspond to regions that are selected. To achieve sparse estimation, we adopt compactly supported and potentially over-complete basis to capture local features of the regression coefficient function, and assume a spike-slab prior to the coefficients of the bases functions. To encourage continuous shrinkage of nearby regions, we assume an Ising hyper-prior which takes into account the neighboring structure of the bases functions. This neighboring structure is represented by an undirected graph. We perform posterior sampling through Markov chain Monte Carlo algorithms. The practical performance of the proposed approach is demonstrated through simulations as well as near-infrared and sonar data.
The second part of this dissertation focuses on constructing diversified portfolios using stock return data in the Center for Research in Security Prices (CRSP) database maintained by the University of Chicago. Diversification is a risk management strategy that involves mixing a variety of financial assets in a portfolio. This strategy helps reduce the overall risk of the investment and improve performance of the portfolio. To construct portfolios that effectively diversify risks, we first construct a co-movement network using the correlations between stock returns over a training time period. Correlation characterizes the synchrony among stock returns thus helps us understand whether two or multiple stocks have common risk attributes. Based on the co-movement network, we apply multiple network community detection algorithms to detect groups of stocks with common co-movement patterns. Stocks within the same community tend to be highly correlated, while stocks across different communities tend to be less correlated. A portfolio is then constructed by selecting stocks from different communities. The average return of the constructed portfolio over a testing time period is finally compared with the SandP 500 market index. Our constructed portfolios demonstrate outstanding performance during a non-crisis period (2004-2006) and good performance during a financial crisis period (2008-2010).PHD
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Klusman, Craig Raymond. "Two-Dimensional Analysis of Stacked Geosynthetic Tubes." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/35316.
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Geosynthetic tubes filled with a slurry-mix are considered. The mix is usually dredged from a nearby area and pumped directly into the tubes. The tubes are used in a variety of applications including breakwaters, groins, and temporary levees. This thesis considers single and stacked geosynthetic tubes resting on rigid and deformable foundations.
A two-dimensional analysis is performed on the cross-section of a very long tube. The program Mathematica is utilized for the analysis. A few assumptions are made regarding the general behavior of the tube. The tube is assumed to be an inextensible membrane with no bending stiffness. To allow for a closed-form integral solution, it is assumed that no friction exists between the tubes and at the foundation.
A single tube, two stacked tubes, and a 2-1 formation are studied. Both rigid and deformable foundations are considered. The deformable foundation is modeled as a tensionless Winkler foundation with normal forces proportional to the downward deflection of the ground. An external water load on one side is also investigated for a single tube and a 2-1 formation, with rigid blocks to prevent the structure from sliding along the ground. Example cross-sectional profiles are given. Results from the analysis include structure height, circumferential tension, and ground deflections.Master of Science
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Green, Brittany. "Ultra-high Dimensional Semiparametric Longitudinal Data Analysis." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1593171378846243.
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Longstaff, Wilmer Gregg. "Three-dimensional analysis of optical transition radiation." Thesis, Monterey, California. Naval Postgraduate School, 1988. http://hdl.handle.net/10945/23428.
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Approved for public release; distribution is unlimitedA three dimensional analysis of the intensity distribution of backward optical transition radiation has been performed. The effects of variations in electron energy and beam divergence and on material properties such as dielectric permittivities and the resultant coherence length upon the angular distribution and polarization of optical transition radiation has been investigated. A surprising observation important to the use of optical transition radiation as a diagnostic tool for high energy electron beams is the behavior of the perpendicular component of the intensity. In contrast to low energies where the parallel component dominates, at electron energies above 200 MeV, the perpendicular component dominates. This requires the use of a polarization filter to diagnose particle beam properties at high energies.
http://archive.org/details/threedimensional00long
Lieutenant, United States Navy
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Li, Jian-Chuan. "Three dimensional kinetic analysis of asymmetrical lifting." Thesis, Rhodes University, 1996. http://hdl.handle.net/10962/d1018240.
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Manual lifting is dynamic in nature and involves asymmetrical loading of the human body. This study investigated kinematic and kinetic characteristics of asymmetrical lifting in three dimensions, and then constructed a 3-D biomechanical force model of the lower back which is capable of quantifying torsional stress on the human spine. Eleven healthy adult male manual workers were recruited as subjects and lifted a 1 Okg load placed at the sagittal plane (0°) and at 30°, 60° and 90° lateral planes to the right, from 150mm and 500mm initial lift heights, respectively, to an 800mm high bench in the sagittal plane. Subjects' spinal motions and the trajectorial movements of the load in three-dimensional space were monitored simultaneously by a Lumbar Motion Monitor and a V-scope Motion Analyzer. Generally, the spinal motion factors increased as a function of increasing task asymmetry and differed (p < 0.05) between the lower (150mm) and higher (500mm) levels in the sagittal plane. In all asymmetrical conditions the motion factors showed a dramatic increase at the 500mm level compared to the increase at the 150mm level. The rates of increase in the horizontal and frontal planes were greater than those in the sagittal plane. Task asymmetry had a significant effect on the spinal kinematic parameters in the frontal plane at the two lift heights, and only at the high level (500mm) in the horizontal plane, with exception of average acceleration . Initial lift height exerted a significant effect on peak velocity and acceleration in both frontal and horizontal planes and on range of motion in the horizontal plane. Kinetic characteristics of the object being lifted in three-dimensions increased with an increase in task asymmetry. The increase was more dramatic in the lateral direction in the horizontal plane. However, motion factors in the vertical direction dominated the full range of the lift, irrespective of task asymmetry and lift height. The kinetic measures differed (p < 0.05) between the lower ( 1 50mm) and the higher (500mm) levels in the vertical direction except for average force. Task asymmetry had a significant effect on dynamic measures in the anterior-posterior direction. Both task asymmetry and lift height had a significant effect on dynamic motion factors in the lateral direction. From insights gained in the empirical study a three-dimensional biomechanical force model of the lower back was constructed based on a mechanism of muscle force re-orientation in the lumbar region. Acknowledging that the lower back is designed to be able to rotate around its longitudinal axis, the proposed model accounts for compression and shear forces and a torsional moment. The model has similar predictability to Schultz and Andersson's (1981) model when the human trunk exerts only a flexion-extension moment in the sagittal plane, but additionally predicts dramatic increases in shear forces, oblique muscle forces and torsional moment under asymmetrical lifting conditions which the Schultz-Andersson model does not. The increase rates in these forces and moment are not linearly related over task asymmetric angle.
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Gardner, Elizabeth Mary. "Two-dimensional infrared spectroscopy for protein analysis." Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/5602.
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A number of forms of coherent multi-dimensional vibrational spectroscopy (CMDVS) have been identified as being useful for addressing a range of biological problems. Here a particular member of this family of spectroscopies, electronvibration- vibration two-dimensional infrared (EVV 2DIR) spectroscopy (also known as DOubly-Vibrationally Enhanced InfraRed (DOVE-IR)), is explored for its possible utility for two particular bioanalytical applications; protein identification and the study of enzyme mechanisms. The main focus of this work is on the development of EVV 2DIR as a tool for high-throughput, label-free proteomics, in particular for protein identification and absolute quantification. The protein fingerprinting strategy is based on the identification of proteins through their spectroscopically determined amino acid compositions. To this end, spectral signatures of amino acid side chains (tyrosine, phenylalanine and tryptophan) have been identified, as well as those from CH2 and CH3 groups which have been found to be appropriate for use as internal references. The intensities of these cross peaks are measured to give proteins’ amino acid compositions in the form of amino acid / CHx ratios. Specialised databases comprising the amino acid / CHx ratios of proteins have been developed for achieving protein identifications using the EVV 2DIR data. The second strand of this research considers the potential of triply resonant EVV 2DIR for studying protein structures and mechanisms. It is possible to use the electronic polarising properties of EVV 2DIR to good effect to achieve significant enhancement of the signal size when probing a chromophore. Here this effect is demonstrated for the case of bacteriorhodopsin (bR) membranes isolated from Halobacterium salinarium. The signal enhancement that is achievable from the retinal chromophore at the heart of bR makes it possible to study this whilst avoiding the surrounding protein.
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Punyamurthula, Sujan. "Three-dimensional analysis of waste impoundment stability /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/10210.
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Conrad, Bryan Preston. "Three-dimensional kinematic analysis of spine motion." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0041210.
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Taiebat, Hossein Ali. "THREE DIMENSIONAL LIQUEFACTION ANALYSIS OF OFFSHORE FOUNDATIONS." Thesis, The University of Sydney, 1999. http://hdl.handle.net/2123/499.
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This thesis presents numerical techniques which have been developed to analyse three dimensional problems in offshore engineering. In particular, the three dimensional liquefaction analysis of offshore foundations on granular soils is the main subject of the thesis. The subject matter is broadly divided into four sections: 1)Development of an efficient method for the three dimensional elasto?plastic finite element analysis of consolidating soil through the use of a discrete Fourier representation of field quantities. 2)Validation of the three dimensional method through analyses of shallow offshore foundations subjected to three dimensional loading and investigation of the yield locus for foundations on purely cohesive soils. 3)Formulation of governing equations suitable for three dimensional liquefaction analyses of offshore foundations founded on granular soil, presentation of a method for liquefaction analyses, and application of the method in modified elastic liquefaction analyses of offshore foundations. 4)Application of a conventional elasto?plastic soil model in the liquefaction analyses of offshore foundations using the three dimensional finite element method. The finite element method developed in this thesis provides a rigorous and efficient numerical tool for the analysis of geotechnical problems subjected to three dimensional loading. The efficiency of the numerical tool makes it possible to tackle some of the problems in geotechnical engineering which would otherwise need enormous computing time and thus would be impractical. The accuracy of the numerical scheme is demonstrated by solving the bearing capacity problem of shallow foundations subjected to three dimensional loading. The generalized governing equations and the numerical method for liquefaction analyses presented in this thesis provide a solid base for the analysis of offshore foundations subjected to cyclic wave loading where they are founded on potentially liquefiable soil. The practicability of the numerical scheme is also demonstrated by a modified elastic liquefaction analysis of offshore foundations. The liquefaction phenomenon is redefined in the context of the conventional Mohr?Coulomb model, so that a relatively simple and practical model for elasto?plastic liquefaction analysis is presented. The three dimensional finite element method together with the numerical scheme for liquefaction analysis and the elasto?plastic soil model provide a suitable practical engineering tool for exploring the responses of offshore foundations subjected to cyclic wave loading.
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Taiebat, Hossein Ali. "THREE DIMENSIONAL LIQUEFACTION ANALYSIS OF OFFSHORE FOUNDATIONS." University of Sydney. Civil Engineering, 1999. http://hdl.handle.net/2123/499.
Full textAbstract:
This thesis presents numerical techniques which have been developed to analyse three dimensional problems in offshore engineering. In particular, the three dimensional liquefaction analysis of offshore foundations on granular soils is the main subject of the thesis. The subject matter is broadly divided into four sections: 1)Development of an efficient method for the three dimensional elasto?plastic finite element analysis of consolidating soil through the use of a discrete Fourier representation of field quantities. 2)Validation of the three dimensional method through analyses of shallow offshore foundations subjected to three dimensional loading and investigation of the yield locus for foundations on purely cohesive soils. 3)Formulation of governing equations suitable for three dimensional liquefaction analyses of offshore foundations founded on granular soil, presentation of a method for liquefaction analyses, and application of the method in modified elastic liquefaction analyses of offshore foundations. 4)Application of a conventional elasto?plastic soil model in the liquefaction analyses of offshore foundations using the three dimensional finite element method. The finite element method developed in this thesis provides a rigorous and efficient numerical tool for the analysis of geotechnical problems subjected to three dimensional loading. The efficiency of the numerical tool makes it possible to tackle some of the problems in geotechnical engineering which would otherwise need enormous computing time and thus would be impractical. The accuracy of the numerical scheme is demonstrated by solving the bearing capacity problem of shallow foundations subjected to three dimensional loading. The generalized governing equations and the numerical method for liquefaction analyses presented in this thesis provide a solid base for the analysis of offshore foundations subjected to cyclic wave loading where they are founded on potentially liquefiable soil. The practicability of the numerical scheme is also demonstrated by a modified elastic liquefaction analysis of offshore foundations. The liquefaction phenomenon is redefined in the context of the conventional Mohr?Coulomb model, so that a relatively simple and practical model for elasto?plastic liquefaction analysis is presented. The three dimensional finite element method together with the numerical scheme for liquefaction analysis and the elasto?plastic soil model provide a suitable practical engineering tool for exploring the responses of offshore foundations subjected to cyclic wave loading.
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Ostasevicius, Tomas. "Multi-dimensional data analysis in electron microscopy." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/269286.
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This thesis discusses various large multi-dimensional dataset analysis methods and their applications. Particular attention is paid to non-linear optimization analyses and general processing algorithms and frameworks when the datasets are significantly larger than the available computer memory. All new presented algorithms and frameworks were implemented in the HyperSpy analysis toolbox. A novel Smart Adaptive Multi-dimensional Fitting (SAMFire) algorithm is presented and applied across a range of scanning transmission electron microscope (STEM) experiments. As a result, the Stark effect in quantum disks was mapped in a cathodoluminescence STEM experiment, and fully quantifiable 3D atomic distributions of a complex boron nitride core-shell nanoparticle were reconstructed from an electron energy loss spectrum (EELS) tilt-series. The EELS analysis also led to the development of two new algorithms to extract EELS near-edge structure fingerprints from the original dataset. Both approaches do not rely on standards, are not limited to thin or constant thickness particles and do not require atomic resolution. A combination of the aforementioned fingerprinting techniques and SAMFire allows robust quantifiable EELS analysis of very large regions of interest. A very large dataset loading and processing framework, “LazySignal”, was developed and tested on scanning precession electron diffraction (SPED) data. A combination of SAMFire and LazySignal allowed efficient analysis of large diffraction datasets, successfully mapping strain across an extended (ca. 1 μm × 1 μm) region and classifying the strain fields around precipitate needles in an aluminium alloy.
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Dong, Kai. "High-dimensional covariance matrix estimation with application to Hotelling's tests." HKBU Institutional Repository, 2015. https://repository.hkbu.edu.hk/etd_oa/191.
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In recent years, high-dimensional data sets are widely available in many scientific areas, such as gene expression study, finance and others. Estimating the covariance matrix is a significant issue in such high-dimensional data analysis. This thesis focuses on high-dimensional covariance matrix estimation and its application. First, this thesis focuses on the covariance matrix estimation. In Chapter 2, a new optimal shrinkage estimation of the covariance matrices is proposed. This method is motivated by the quadratic discriminant analysis where many covariance matrices need to be estimated simultaneously. We shrink the sample covariance matrix towards the pooled sample covariance matrix through a shrinkage parameter. Some properties of the optimal shrinkage parameter are investigated and we also provide how to estimate the optimal shrinkage parameter. Simulation studies and real data analysis are also conducted. In Chapter 4, we estimate the determinant of the covariance matrix using some recent proposals for estimating high-dimensional covariance matrix. Specifically, a total of nine covariance matrix estimation methods will be considered for comparison. Through extensive simulation studies, we explore and summarize some interesting comparison results among all compared methods. A few practical guidelines are also made on the sample size, the dimension, and the correlation of the data set for estimating the determinant of high-dimensional covariance matrix. Finally, from a perspective of the loss function, the comparison study in this chapter also serves as a proxy to assess the performance of the covariance matrix estimation. Second, this thesis focuses on the application of high-dimensional covariance matrix estimation. In Chapter 3, we consider to estimate the high-dimensional covariance matrix based on the diagonal matrix of the sample covariance matrix and apply it to the Hotelling’s tests. In this chapter, we propose a shrinkage-based diagonal Hotelling’s test for both one-sample and two-sample cases. We also propose several different ways to derive the approximate null distribution under different scenarios of p and n for our proposed shrinkage-based test. Simulation studies show that the proposed method performs comparably to existing competitors when n is moderate or large, and it is better when n is small. In addition, we analyze four gene expression data sets and they demonstrate the advantage of our proposed shrinkage-based diagonal Hotelling’s test. Apart from the covariance matrix estimation, we also develop a new classification method for a specific type of high-dimensional data, RNA-sequencing data. In Chapter 5, we propose a negative binomial linear discriminant analysis for RNA-Seq data. By Bayes’ rule, we construct the classifier by fitting a negative binomial model, and propose some plug-in rules to estimate the unknown parameters in the classifier. The relationship between the negative binomial classifier and the Poisson classifier is explored, with a numerical investigation of the impact of dispersion on the discriminant score. Simulation results show the superiority of our proposed method. We also analyze four real RNA-Seq data sets to demonstrate the advantage of our method in real-world applications. Keywords: Covariance matrix, Discriminant analysis, High-dimensional data, Hotelling’s test, Log determinant, RNA-sequencing data.
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Barry, Sarah Jane Elizabeth. "Longitudinal analysis of three-dimensional facial shape data." Connect to e-thesis, 2008. http://theses.gla.ac.uk/190/.
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Thesis (Ph.D.) - University of Glasgow, 2008.Ph.D. thesis submitted to the Faculty of Information and Mathematical Sciences, Department of Statistics, University of Glasgow, 2008. Includes bibliographical references. Print version also available.
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Schurch, Brandt Roger. "Three-dimensional imaging and analysis of electrical trees." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/threedimensional-imaging-and-analysis-of-electrical-trees(73e032f6-3e6b-4ee9-9cc1-953a11f36cb3).html.
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Electrical trees are micrometre-size tubular channels of degradation in high voltage polymeric insulation, a precursor to failure of electrical power plant. Hence, electrical trees critically affect the reliability of power systems and the performance of new insulation designs. Imaging laboratory-grown electrical trees has been an important tool for studying how trees develop. Commonly, electrical trees prepared in transparent or translucent polymers are imaged using traditional optical methods. Consequently, most of the analysis has been based on two-dimensional (2D) images of trees, thus, valuable information may be lost. However, electrical trees are complex interconnected structures that require a tree-dimensional (3D) approach for more complete analysis. This thesis investigates a method for imaging and analysis of electrical trees to characterise their 3D structure and provide a platform for further modelling. Laboratory created electrical trees were imaged using X-ray Computed Tomography (XCT) and Serial Block-Face Scanning Electron Microscopy (SBFSEM), 3D imaging techniques that provide sub-micrometre spatial resolution. Virtual replicas of the trees, which are the 3D geometrical models representing the real electrical trees, were generated and new indices to characterise the 3D structure of electrical trees were developed. These parameters were indicative of differences in tree growth and thus, they can be used to investigate patterns and classify the structure of electrical trees. The progression of the tree was analysed using cross-sections of the tree that are orthogonal to the growth: the number of tree channels and area covered by them were measured. The fractal dimension of the tree was calculated from the 3D model and from the 2D projections, the latter being lower for all the tree-type structures studied. Parameters from the skeleton of the tree such as number of nodes, segment length, tortuosity and branch angle were measured. Most of the mean segment lengths ranged 6-13 µm, which is in accordance to the 10µm proposed by various tree-growth models. The capabilities of XCT and SBFSEM imaging techniques were evaluated in their application to electrical trees. Bush and branch trees, including early-growth electrical trees (of length 20-40 µm), were analysed and compared using the comprehensive tool of visualisation and characterisation developed. A two-stage tree-growth experiment was conducted to analyse the progression and development of tree branches using XCT: tree channels after the second stage of growth were wider than after the first, while the fractal dimension remained the same. The capabilities of XCT and SBFSEM were tested for imaging electrical trees in optically-opaque materials such as micro and nano-filled epoxy compounds. The general structure of trees in epoxy filled up to 20 wt% micro-silica was observed using both techniques. The use of a virtual replica as the 3D geometrical model for the simulation of the electric field distribution using Finite Element Analysis (FEA) was preliminary explored. A combination of the imaging techniques is proposed for a more complete structural analysis of trees. It is believed that a great impact towards understanding electrical treeing will be achieved using the 3D technical platform developed in this thesis.
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Vohra, Neeru Rani. "Three dimensional statistical graphs, visual cues and clustering." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ56213.pdf.
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Zhang, Xiang. "Dimensional analysis based CFD modelling for power transformers." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/dimensional-analysis-based-cfd-modelling-for-power-transformers(49cac27d-38b9-4f23-a6ec-b5106422420c).html.
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Reliable thermal modelling approaches are crucial to transformer thermal design and operation. The highest temperature in the winding, usually referred to as the hot-spot temperature, is of the greatest interest because the insulation paper at the hot-spot undergoes the severest thermal ageing, and determines the life expectancy of the transformer insulation. Therefore, the primary objective of transformer thermal design is to control the hot-spot temperature rise over the ambient temperature within certain limit. For liquid-immersed power transformers, the hot-spot temperature rise over the ambient temperature is controlled by the winding geometry, power loss distribution, liquid flow rate and liquid properties. In order to obtain universally applicable thermal modelling results, dimensional analysis is adopted in this PhD thesis to guide computational fluid dynamics (CFD) simulations for disc-type transformer windings in steady state and their experimental verification. The modelling work is split into two parts on oil forced and directed (OD) cooling modes and oil natural (ON) cooling modes. COMSOL software is used for the CFD simulation work For OD cooling modes, volumetric oil flow proportion in each horizontal cooling duct (Pfi) and pressure drop coefficient over the winding (Cpd) are found mainly controlled by the Reynolds number at the winding pass inlet (Re) and the ratio of horizontal duct height to vertical duct width. The correlations for Pfi and Cpd with the dimensionless controlling parameters are derived from CFD parametric sweeps and verified by experimental tests. The effects of different liquid types on the flow distribution and pressure drop are investigated using the correlations derived. Reverse flows at the bottom part of winding passes are shown by both CFD simulations and experimental measurements. The hot-spot factor, H, is interpreted as a dimensionless temperature at the hot-spot and the effects of operational conditions e.g. ambient temperature and loading level on H are analysed. For ON cooling modes, the flow is driven by buoyancy forces and hot-streak dynamics play a vital role in determining fluid flow and temperature distributions. The dimensionless liquid flow and temperature distributions and H are all found to be controlled by Re, Pr and Gr/Re2. An optimal design and operational regime in terms of obtaining the minimum H, is identified from CFD parametric sweeps, where the effects of buoyancy forces are balanced by the effects of inertial forces. Reverse flows are found at the top part of winding passes, opposite to the OD results. The total liquid flow rates of different liquids for the same winding geometry with the same power loss distribution in an ON cooling mode are determined and with these determined total liquid flow rates, the effects of different liquids on fluid flow and temperature distributions are investigated by CFD simulations. The CFD modelling work on disc-type transformer windings in steady state present in this PhD thesis is based on the dimensional analyses on the fluid flow and heat transfer in the windings. Therefore, the results obtained are universally applicable and of the simplest form as well. In addition, the dimensional analyses have provided insight into how the flow and temperature distribution patterns are controlled by the dimensionless controlling parameters, regardless of the transformer operational conditions and the coolant liquid types used.
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Li, Hao. "Feature cluster selection for high-dimensional data analysis." Diss., Online access via UMI:, 2007.
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Skantzos, Nikolaos Stavrou. "Statistical mechanical analysis of (1 + ∞) dimensional disordered systems." Thesis, King's College London (University of London), 2001. https://kclpure.kcl.ac.uk/portal/en/theses/statistical-mechanical-analysis-of-1--infinity-dimensional-disordered-systems(b16e7dd9-85df-4e71-b8c6-0c6c28062961).html.
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Strehl, Alexander. "Relationship-based clustering and cluster ensembles for high-dimensional data mining." Thesis, Full text (PDF) from UMI/Dissertation Abstracts International, 2002. http://wwwlib.umi.com/cr/utexas/fullcit?p3088578.
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Willemse, Chandre Monique. "Comprehensive two-dimensional liquid chromatographic analysis of anthocyanins." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96675.
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Thesis (PhD)--Stellenbosch University, 2015.ENGLISH ABSTRACT: Anthocyanins are naturally occurring pigments responsible for the colour of many natural products, including grapes and wine. These pigments are important to the food industry and have been recognised for their nutritional value since they play an important role in the reduced risk of various chronic diseases in humans. Anthocyanins also play an important role in the aesthetic perception and quality of red wine. However, due to the large structural diversity of grape-derived anthocyanins and the many derivatives formed from these during wine ageing, the accurate analysis of wine pigments is extremely challenging. Reversed-phase liquid chromatography (RP-LC) is mostly used for anthocyanin analysis, although the technique often provides insufficient resolving power for complex mixtures of anthocyanins. In addition, the lack of commercially available standards and identical mass spectral characteristics hampers identification of these compounds. The coupling of multiple orthogonal separation systems in comprehensive 2-dimensional liquid chromatography (LC×LC) offers a more powerful approach for the separation of complex mixtures. The current work therefore focussed on exploring the potential of LC×LC for the improved analysis of anthocyanins and derived pigments in natural products and wine. The first part of this work focussed on developing a hydrophilic interaction chromatography (HILIC) method as an alternative to RP-LC for the anthocyanin analysis. Following extensive optimisation, the method proved suitable for the analysis of a diverse range of anthocyanins in natural products. Significantly, it also showed alternative selectivity compared to RP-LC. The optimised HILIC method was then used in combination with RP-LC to develop an off-line LC×LC approach for anthocyanins. For this purpose, half-minute fractions of the HILIC effluent were collected and reinjected onto a RP-LC column. The off-line HILIC×RP-LC method demonstrated exceptionally high resolving power, as measured in terms of the practical peak capacity, with many compounds separated in two dimensions that co-eluted in 1-dimensional HPLC. Interestingly, group-type separation was also observed based on the degree and/or nature of glycosylation and acylation of anthocyanins. In the final part of the work, a systematic approach was used for the development and optimisation of and on-line HILIC×RP-LC method by using a 10-port switching valve to automatically transfer fractions between the two columns. This method was then coupled to high resolution mass spectrometry (MS) to allow the detailed investigation of anthocyanins and derived products in wine. Ninety four pigments were identified in one- and six-year old Pinotage wines based on HILIC×RPLC separation in combination with accurate mass MS data and fragmentation information. Significant differences in especially the content of derived pigments were observed between the wines. In summary, the methods developed in this work provide the means to improve anthocyanin analysis, and therefore also show promise for the detailed investigation of these important compounds and their alteration in natural products and their derived commodities.
AFRIKAANSE OPSOMMING: Antosianiene is natuurlike pigmente wat verantwoordelik is vir die kleur van baie natuurlike produkte, insluitende dié van druiwe en wyn. Hierdie pigmente is belangrik vir die voedsel industrie en word gereken vir hul voedingswaarde aangesien hulle 'n belangrike rol speel in die verlaagde risiko van verskeie chroniese siektes onder die mens. Antosianiene speel ook 'n belangrike rol in die estetiese persepsie en kwaliteit van rooiwyn. Desnieteenstaande, as gevolg van die groot strukturele diversiteit van druifgeproduseerde antosianiene en die vele chemiese afgeleides wat uit hulle gevorm kan word tydens wyn bereiding en veroudering, is die akkurate analise van natuurlike wyn-pigmente uiters uitdagend. Omgekeerde-fase vloeistofchromatografie (RP-LC) word meestal gebruik vir die analise van antosianiene. Dié tegniek bied egter dikwels onvoldoende skeidingsvermoë vir komplekse mengsels van antosianiene en verwante molekules. Verder belemmer die onbeskikbaarheid van kommersiële standaarde en identiese massa spektrale eienskappe die identifikasie van hierdie verbindings. Die kombinasie van verskillende ortogonale skeidings meganismes in omvattende 2- dimensionele vloeistofchromatografie (LC×LC) bied egter 'n baie kragtiger benadering vir die skeiding van komplekse mengsels. Die huidige werk fokus dus op die ontginning van die potensiaal van LC×LC vir die verbeterde ontleding van antosianiene en verwante afgeleide pigmente in natuurlike produkte en wyn. Die eerste deel van hierdie werk het gefokus op die ontwikkeling van 'n hidrofiliese interaksie chromatografiese (HILIC) metode as ʼn alternatief vir RP-LC analise van antosianiene. Na uitgebreide optimisering, is gevind dat die metode geskik is vir die ontleding van 'n verskeidenheid van antosianiene in natuurlike produkte. Van groot belang is dat dit ook alternatiewe selektiwiteit in vergelyking met RP-LC demonstreer. Hierdie geoptimiseerde HILIC metode word dan voorts gebruik in kombinasie met RP-LC vir die ontwikkeling van ʼn af-lyn LC×LC benadering vir die analise van antosianiene. Hiervoor is half-minuut fraksies van die HILIC uitvloei opgevang en her-ingespuit op 'n RP-LC kolom. Dié af-lyn HILIC×RP-LC metode toon buitengewoon hoë skeidingsvermoë, gemeet in terme van die bereikbare praktiese piek kapasiteit, met baie verbindings wat geskei is in die twee dimensies wat saam elueer in 1-dimensionele HPLC. Interessant genoeg is groep-tipe skeiding ook waargeneem gebaseer op die graad en / of aard van glukosilasie en asilering van die antosianiene. In die laaste deel van die werk, is 'n sistematiese benadering gevolg vir die ontwikkeling en optimisering van ʼn aan-lyn HILIC×RP-LC deur gebruik te maak van 'n 10-poort oorskakelingsklep wat fraksies outomaties oordra tussen die twee kolomme. Die bogenoemde metode is ook verder gekoppel aan hoë resolusie massaspektrometrie (HR-MS) om ʼn gedetailleerde ondersoek van antosianiene en hulle afgeleide verbindings in wyn moontlik te maak. Vier en negentig pigmente is in een- en ses jaar oue Pinotage wyne geïdentifiseer gebaseer op HILIC×RP-LC skeiding in kombinasie met akkurate massa MS data en fragmentasie inligting. Beduidende verskille in veral die inhoud van antosianien-afgeleide pigmente is tussen die wyne waargeneem. Ter samevatting, die metodes ontwikkel in hierdie werk baan die weg om antosianien ontleding te verbeter en stel gevolglik die moontlikheid van selfs meer gedetailleerde studies van hierdie belangrike verbindings in natuurlike produkte in die vooruitsig.
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Lee, Wai Hong. "Variable selection for high dimensional transformation model." HKBU Institutional Repository, 2010. http://repository.hkbu.edu.hk/etd_ra/1161.
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Choo, Jae gul. "Integration of computational methods and visual analytics for large-scale high-dimensional data." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49121.
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With the increasing amount of collected data, large-scale high-dimensional data analysis is becoming essential in many areas. These data can be analyzed either by using fully computational methods or by leveraging human capabilities via interactive visualization. However, each method has its drawbacks. While a fully computational method can deal with large amounts of data, it lacks depth in its understanding of the data, which is critical to the analysis. With the interactive visualization method, the user can give a deeper insight on the data but suffers when large amounts of data need to be analyzed.
Even with an apparent need for these two approaches to be integrated, little progress has been made. As ways to tackle this problem, computational methods have to be re-designed both theoretically and algorithmically, and the visual analytics system has to expose these computational methods to users so that they can choose the proper algorithms and settings. To achieve an appropriate integration between computational methods and visual analytics, the thesis focuses on essential computational methods for visualization, such as dimension reduction and clustering, and it presents fundamental development of computational methods as well as visual analytic systems involving newly developed methods.
The contributions of the thesis include (1) the two-stage dimension reduction framework that better handles significant information loss in visualization of high-dimensional data, (2) efficient parametric updating of computational methods for fast and smooth user interactions, and (3) an iteration-wise integration framework of computational methods in real-time visual analytics. The latter parts of the thesis focus on the development of visual analytics systems involving the presented computational methods, such as (1) Testbed: an interactive visual testbed system for various dimension reduction and clustering methods, (2) iVisClassifier: an interactive visual classification system using supervised dimension reduction, and (3) VisIRR: an interactive visual information retrieval and recommender system for large-scale document data.