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1
Peskett, Jonathan Paul. « The development of unsteady aerodynamic mathematical models ». Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299504.
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Jones, Bleddyn. « The development of mathematical models in radiation oncology ». Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430761.
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He, Yumei, et 何玉梅. « Essays on public infrastructure, industrial location and regional development ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B39707313.
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Dang, Van To Civil & Environmental Engineering Faculty of Engineering UNSW. « Development of a mathematical N-line model for simulation of beach changes ». Awarded by:University of New South Wales. School of Civil and Environmental Engineering, 2006. http://handle.unsw.edu.au/1959.4/27394.
Texte intégralRésumé :
The development of a new N-Line model, which provides a practical tool for simulating regional beach changes induced by short and long-term processes, is described in this thesis. The new N-Line model consists of four main modules that together describe the hydrodynamic and morphological responses. The four constituent modules have been integrated based on a wide range of research including the utility and function of commercial or freeware models. They are RCPWAVE wave module, time-averaged and depth-integrated current module, sediment transport module based on Bailard (1981) and contour change morphological module. Two different time-scales and two staggered grid systems for hydrodynamic and morphological simulations were adopted alternatively. For short-term 2D profile changes, new N-Line model applicability has been examined using data from the laboratory to the field. For ideal beaches, new N-Line can simulate an offshore storm bar generation or an onshore accretion due to high or low energy waves. For SUPERTANK large-scale flume data, the predicted profile matched the measured profile well, especially the bar height and position. For beach profile data from the Gold Coast, storm-induced variations of barred profiles were reasonably modelled. The new N-Line model compared well with other commonly used cross-shore models such as SBEACH and UNIBEST. A new schematisation for a non-monotonic profile and DUNED inclusion were introduced. Sensitivity tests on cross-shore sediment coefficient (Kq), smoothing parameter (??s) and water level fluctuations were performed. For long-term 3D beach changes, the new N-Line model applicability has been tested with various boundary conditions using idealized and real field data. Two periods, 17 and 16 months, of beach changes before and after a major bypass plant commenced operation in 2001 at Letitia Spit were simulated. The profile and shoreline changes were predicted reasonably well. Empirical model parameters were determined after a range of sensitivity and calibration testing. The new N-Line model showed its better performance compared to one-line models. It can handle various boundary conditions, especially bypass conditions. The N-Line model is not only capable of modelling planform variations but also cross-shore profile changes.
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Ahmed, Ishraq Uddin. « Multiphase models of early atherosclerotic plaque development ». Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/25883.
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Atherosclerosis is a complex disease caused by a cascade of interactions between the artery wall, immune cells, cholesterol-carrying lipoproteins, and a host of other cellular and chemical species. In this thesis, we build and investigate a series of partial differential equation models for the early atherosclerotic plaque based on a multiphase framework. We first develop a general approach for building multiphase PDE models that can account for cell crowding effects, while also supporting a variable domain size by using a free boundary. Using this framework, we build a series of increasingly complex models to address different aspects of early plaque development. The first is a simple two-phase model comprising macrophage foam cells and atherogenic low density lipoproteins (LDL). Subsequent models extend this basic model to incorporate spatial heterogeneity in macrophage lipid content, apoptotic cell death, the recycling of dead material via efferocytosis, and the atheroprotective role of high density lipoproteins (HDL). Where appropriate, we also make use of simplified ODE submodels for local plaque composition. We use these PDE models to address a number of phenomena, including the competing effects of LDL and HDL, the balance between cell death and recycling, the cytotoxic effects of intracellular cholesterol, the ability for inflammation to either relieve or exacerbate plaque growth, and the ability of HDL and foam cell emigration to slow plaque growth and potentially stabilise plaque size. The full model is also applied to several experimental setups. We first simulate therapies that affect blood lipid profiles, examining how their efficacy depends on when and how long they are administered. We also simulate mouse model studies involving bead-tagged macrophages, and we assess hypotheses regarding macrophage motility in the deep plaque by comparing simulated and experimental bead distributions.
6
Zoebelein, Till. « Development of an LU-scheme for the solution of hypersonic non-equilibrium flow ». Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/12509.
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Duan, Qingyun, Soroosh Sorooshian et Richard P. Ibbitt. « DEVELOPMENT AND VALIDATION OF A NEW MAXIMUM LIKELIHOOD CRITERION SUITABLE FOR DATA COLLECTED AT UNEQUAL TIME INTERVALS ». Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ), 1987. http://hdl.handle.net/10150/617640.
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A new Maximum Likelihood Criterion (MLE) suitable for data which are
recorded at unequal time intervals and contain auto-correlated errors is developed.
Validation of the new MLE criterion has been carried out both on a simple two -
parameter reservoir model using synthetical data and on a more complicated hillslope
model using real data from the Pukeiti Catchment in New Zealand. Comparison
between the new MLE criterion and the Simple Least Squares (SLS) criterion reveals
the superiority of the former over the latter. Comparison made between the new
MLE and the MLE for auto-correlated case proposed by Sorooshian in 1978 has
shown that both criteria would yield results with no practical difference if equal
time interval data were used. However, the new MLE can work on variable time
interval data which provide more information than equal time interval data, and
therefore produces better visual results in hydrologic simulations.
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Alavi, Hajar Karimi. « Development of mechanistic mathematical models for gene-mediated drug-drug interactions ». Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/development-of-mechanistic-mathematical-models-for-genemediated-drugdrug-interactions(b38da88a-bb2a-4667-9809-21a09c8feeeb).html.
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The glucocorticoid receptor (GR) is a member of the nuclear hormone receptors family and has been shown to exert significant effects on the induction of cytochrome P450 (CYP) enzymes responsible for the metabolism of many xenobiotics. CYP3A4/5 and CYP2C9 are important CYP enzymes which metabolise more that 60% of drugs. Induction or inhibition of the enzymatic activity and the levels of these enzymes can have significant effects on drug metabolism. Understanding the role of GR and other nuclear receptors, pregnane X receptor (PXR) and the constitutive androstane receptor (CAR), in the mechanisms effecting CYP3A4/5 and CYP2C9 levels and activity can aid in the development of in vitro and in vivo models which have become a target for scientists in the clinic and the industry. The commonly prescribed synthetic glucocorticoid (GC) drug, dexamethasone (Dex), can induce GR, PXR and CAR and was used in this study to analyse its effects on the CYP enzymes studied. The hypothesis of this project was that changes in CYP3A4/5 and CYP2C9 gene expression affect drug metabolism and changes in gene expression of these CYP enzymes was under GR, PXR and CAR control, thus affecting the concentration and therapeutic activity of drugs metabolized by these enzymes during chronic use of GCs in conditions such as rheumatoid arthritis and asthma. This study aimed to measure mRNA, protein, ROS and enzymatic activity levels in human HepG2 hepatocytes treated with Dex for 120 h and analyze the results for various time points to produce a mathematical model. Our study has shown that changes in mRNA, protein and enzymatic activity levels of CYP3A4/5 and CYP2C9 in HepG2 cells were induced by Dex at sub-micromolar (0.1 µM) and supra-micromolar (1.5 mM) concentrations. The induction of CYP3A4/5 and CYP2C9 enzymes during 120 h treatment with Dex may be affected by the NRs studied; GR, phosphorylated GR, PXR and CAR protein levels were also shown to be induced by Dex. The efflux transporter, P-gp’s protein levels were also induced by 0.1 µM Dex, highlighting the importance of considering bioavailability of other drugs co-administered with Dex. The results of some of these laboratory experiments have been used to produce mechanistic mathematical models by MATLAB software with reference to previous studies in rats concentrating on the effects of steroids on GR. The models developed were not effective at the lower Dex concentration of 0.1 µM but were better modelled at the higher Dex concentration of 1.5 mM. The basic mechanistic models developed using HepG2 cells in this study can be utilised to design and conduct drug-drug interaction (DDI) analyses of the induction of CYP3A4/5 and CYP2C9 in other human liver cells and starting pre-clinical studies in animals to aid in drug development.
9
Khan, Maudood Naeem. « Development and application of an adaptive grid air quality model ». Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/20824.
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Shestakova, Anzhela. « Development of mathematical models for freight cars subject to dynamic loading ». Thesis, Keele University, 2015. http://eprints.keele.ac.uk/2343/.
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This research is inspired by mathematical modelling of railcar dynamics and deals with developing a methodology for estimating the impact loads acting on freight cars using measured acceleration data in order to determine their limiting magnitudes for the alarm generation. The developed scheme consists of the following steps. First, artificial neural network technology (ANN) is adapted to predict longitudinal forces in freight cars. Impact tests data for accelerations and forces were used for training ANN. The issue related to the lack of experimental results for training the network is addressed. A possibility of alternative theoretical training using mathematical models is studied. A restricted scope of conventional mathematical models based on rigid body dynamics is discovered. In particular, these models ignore the effect of self-equilibrated loads and internal dissipation. Next, an advanced perturbation model is derived, taking into account low frequency internal motion with inhomogeneous stiffness, density, and viscosity incorporated. The developed advanced model is applied to the evaluation of impact forces arising at coupled impact. The aforementioned model follows from a low-frequency analysis of a viscoelastic inhomogeneous bar, subject to end loads. The longitudinal variation of the problem 2 parameters is taken into consideration. Explicit asymptotic corrections to the conventional equations of rigid body motion are derived in an integro-differential form. The refined equations incorporate the effect of an internal viscoelastic microstructure on the overall dynamic response. Comparison with the exact time-harmonic solutions for extension and bending of a bar demonstrates the efficiency of the developed approach.
11
Zhu, Dewei. « Development and validation of mathematical models for chemical vapor deposition processes / ». The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487686243822723.
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Kamnis, Spyros. « Development of multiphase and multiscale mathematical models for thermal spray process ». Thesis, Aston University, 2007. http://publications.aston.ac.uk/12243/.
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High velocity oxyfuel (HVOF) thermal spraying is one of the most significant developments in the thermal spray industry since the development of the original plasma spray technique. The first investigation deals with the combustion and discrete particle models within the general purpose commercial CFD code FLUENT to solve the combustion of kerosene and couple the motion of fuel droplets with the gas flow dynamics in a Lagrangian fashion. The effects of liquid fuel droplets on the thermodynamics of the combusting gas flow are examined thoroughly showing that combustion process of kerosene is independent on the initial fuel droplet sizes. The second analysis copes with the full water cooling numerical model, which can assist on thermal performance optimisation or to determine the best method for heat removal without the cost of building physical prototypes. The numerical results indicate that the water flow rate and direction has noticeable influence on the cooling efficiency but no noticeable effect on the gas flow dynamics within the thermal spraying gun. The third investigation deals with the development and implementation of discrete phase particle models. The results indicate that most powder particles are not melted upon hitting the substrate to be coated. The oxidation model confirms that HVOF guns can produce metallic coating with low oxidation within the typical standing-off distance about 30cm.
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Pepys, R. C. « Developing mathematical models of complex social processes : radicalisation and criminality development ». Thesis, University College London (University of London), 2016. http://discovery.ucl.ac.uk/1529407/.
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The purpose of this thesis is to examine the use to which mathematical modelling techniques can be put in answering hard questions in social science. The specific area that this thesis focuses on is the development of an individual's propensity for crime or terrorism, with the primary research question answered being: are the process by which an individual develops the propensity to commit crime and the radicalisation process indistinguishable? The answer to this question may assist policy makers and practitioners in the fields of counter-terrorism and crime prevention develop more effective interventions, but it is a difficult question to answer using techniques rooted in social science alone, as crime and terrorism are the outcomes of complex social processes that form part of large socio-ecological systems. The thesis answers this question through the use of mathematical modelling. A model is developed based on the Individual Vulnerability, Exposure and Emergence (IVEE) theoretical framework for radicalisation. This model is realised as a computer simulation imitating the process by which an individual develops the propensity to commit an act of crime or terrorism, and is parameterised using data from secondary sources. The behaviour of the simulation is then explored to determine whether, with sufficient data, it could potentially be of practical use to practitioners: for example, the simulation is used to explore whether crime prevention interventions might also be effective for countering radicalisation, or vice versa. It is concluded that while the simulations developed in this thesis are still theoretical, the models themselves have the potential for further development, and the methodology could be applied to a range of alternative fields.
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Smith, Nigel Stuart Allen. « Development of the conditional moment closure method for modelling turbulent combustion ». Phd thesis, Department of Mechanical and Mechatronic Engineering, 1994. http://hdl.handle.net/2123/8917.
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Jansson, Andreas Biotechnology & Biomolecular Sciences Faculty of Science UNSW. « Modelling T helper cell activation and development ». Awarded by:University of New South Wales. School of Biotechnology and Biomolecular Sciences, 2006. http://handle.unsw.edu.au/1959.4/30602.
Texte intégralRésumé :
T helper (Th) cell activation and development is one of the most critical events in regulating the adaptive immune response. Understanding its regulation could be of great therapeutical value as many severe diseases are associated with failure in controlling T cell activation and development. However, the regulation of T cell activation appears to be one of the most complex set of cellular and molecular interactions known in the immune system. There is therefore an urgent need for tools to unravel this complexity, and to make use of the quantitative experimental data. To address this issue, mathematical and computational models, based on rigorous biophysical and kinetic data, were developed to study the specific role of some of the major costimulatory molecules involved in Th cell activation, and others developed to investigate proposed theories about mechanisms involved in Th cell differentiation. The simulations of costimulation reveal new implications for the function of the costimulatory molecules CD28 and CTLA-4, and their ligands B7-1 and B7-2, and show how binding affinity, stoichiometric properties, expression levels, and, in particular, competition effects, all profoundly influence complex formation at the immunological synapse. The results support the concept that B7-2 and B7-1 are the dominant ligands of CD28 and CTLA-4, respectively, and indicate that the inability of B7-2 to recruit CTLA-4 to the synapse cannot be, as has been previously proposed, due to the different binding properties of B7-1 and B7-2. Simulations of Th cell development reveal that both instructive and selective processes are likely to be involved in Th cell differentiation. In addition, further simulations indicate that Th2 cells are more likely to become dominant by inhibiting Th1 cells (negative selection), rather than selecting their own growth (positive selection). This thesis also includes an experimental work in which the immunomodulatory role of the bacterial signalling molecule N-3-(oxododecanoyl)-L-homoserine lactone (OdDHL) was analysed. This study strongly suggests that OdDHL suppresses Th cell activation and development, and that it is likely targeting the intracellular signalling events involved in the early stages of Th cell activation.
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Thompson, Brett Morinaga. « Development, Implementation, and Analysis of a Contact Model for an Infectious Disease ». Thesis, University of North Texas, 2009. https://digital.library.unt.edu/ark:/67531/metadc9824/.
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With a growing concern of an infectious diseases spreading in a population, epidemiology is becoming more important for the future of public health. In the past epidemiologist used existing data of an outbreak to help them determine how an infectious disease might spread in the future. Now with computational models, they able to analysis data produced by these models to help with prevention and intervention plans. This paper looks at the design, implementation, and analysis of a computational model based on the interactions of the population between individuals. The design of the working contact model looks closely at the SEIR model used as the foundation and the two timelines of a disease. The implementation of the contact model is reviewed while looking closely at data structures. The analysis of the experiments provide evidence this contact model can be used to help epidemiologist study the spread of an infectious disease based on the contact rate of individuals.
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Erson, E. Zeynep. « Development, Integration and Simulation of Multiscale Mathematical Models of Physiological Processes : A Software Engineering Perspective ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1289789036.
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Drouven, Markus G. « Mixed Integer Programming Models for Shale Gas Development ». Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/874.
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Shale gas development is transforming the energy landscape in the United States. Advances in production technologies, notably the dual application of horizontal drilling and hydraulic fracturing, allow the extraction of vast deposits of trapped natural gas that, until recently, were uneconomic to produce. The objective of this work is to develop mixed-integer programming models to support upstream operators in making faster and better decisions that ensure low-cost and responsible natural gas production from shale formations. We propose a multiperiod mixed-integer nonlinear programming (MINLP) model along with a tailored solution strategy for strategic, quality-sensitive shale gas development planning. The presented model coordinates planning and design decisions to maximize the net present value of a field-wide development project. By performing a lookback analysis based on data from a shale gas producer in the Appalachian Basin, we find that return-to-pad operations are the key to cost-effective shale gas development strategies. We address impaired water management challenges in active development areas through a multiperiod mixed-integer linear programming (MILP) model. This model is designed to schedule the sequence of fracturing jobs and coordinate impaired- and freshwater deliveries to minimize water management expenses, while simultaneously maximizing revenues from gas sales. Based on the results of a real-world case study, we conclude that rigorous optimization can support upstream operators in cost-effectively reducing freshwater consumption significantly, while also achieving effective impaired water disposal rates of less than one percent. We also propose a multiperiod MINLP model and a tailor-designed solution strategy for line pressure optimization in shale gas gathering systems. The presented model determines when prospective wells should be turned in-line, and how the pressure profile within a gathering network needs to be managed to maximize the net present value of a development project. We find that backoff effects associated with turn-in line operations can be mitigated through preventive line pressure manipulations. Finally, we develop deterministic and stochastic MILP models for refracturing planning. These models are designed to determine whether or not a shale well should be restimulated, and when exactly to refracture it. The stochastic refracturing planning model explicitly considers exogenous price forecast uncertainty and endogenous well performance uncertainty. Our results suggest that refracturing is a promising strategy for combatting the characteristically steep decline curves of shale gas wells.
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Campbell, William James. « "When Mathematical Activity Moves You"| An Exploration of the Design and Use of Purposefully Embodied Mathematical Activities, Models, Contexts, and Environments ». Thesis, University of Colorado at Boulder, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10288604.
Texte intégralRésumé :
This dissertation describes a mathematics curriculum and instruction design experiment involving a series of embodied mathematical activities conducted in two Colorado elementary schools Activities designed for this experiment include multi-scalar number line models focused on supporting students’ understanding of elementary mathematics. Realistic Mathematics Education (RME) served as a roadmap for the development of models and problem contexts during the design process, and maintained the focus on mathematics as human activity. Key ideas and insights from scholars who have employed embodied, enactive, ecological, multimodal, and inclusive materialist theories of mathematical activity/cognition on spatiality, human vision, and perception also informed the work. Departing from the sedentary approach to U.S. elementary school mathematics learning and instruction, the designed activities intentionally required students to use their bodies and tools in space to coordinate solutions to mathematical problems. As a design experiment, the research took place in two phases over the course of a year. Phase 1 occurred over 17 days in a suburban 2nd grade public school classroom, and phase 2 consisted of six 55-minute clinical interviews with six student pairs from two 3 rd grade classrooms in an urban public school. Findings from this research included students using the designed models to support mathematical arguments and to increase levels of precision in their mathematical activity. Themes also emerged around the ways that students responded to affordances and constraints of the models, by shifting orientations, authority, and re-purposing and creating new tools. Multi-scalar mathematical models, activities, and activity spaces afforded novel and intentionally embodied ways for students to participate in model-centric mathematical activity.
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Graham, James. « Biomedical image computing : the development and application of mathematical and computational models ». Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/biomedical-image-computing-the-development-and-application-of-mathematical-and-computational-models(0e48e05c-3f86-40f2-932a-28df29292cb8).html.
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Biomedical images contain a great deal of information that is useful and a great deal that is not. Computational analysis and interpretation of biomedical images involves extraction of some or all of the useful information. The useless information can take the form of unwanted clutter or noise that can obscure the useful information or inhibit the interpretation. Various mathematical and computational processes may be applied to reduce the effects of noise and distracting content. The most successful approaches involve the use of mathematical or computational models that express the properties of the required information. Interpretation of images involves finding objects or structures in the image that match the properties of the model. This dissertation describes the development and application of different models required for the interpretation of a variety of different image types arising from clinical medicine or biomedical research. These include:* neural network models, * Point Distribution Models, and the associated Active Shape Models, which have become part of the research toolkit of many academic and commercial organisations, * models of the appearance of nerve fibres in noisy confocal microscope images,* models of pose changes in carpal bones during wrist motion, A number of different application problem are described, in which variants of these methods have been developed and used: * cytogenetics, * proteomics, * assessing bone quality, * segmentation of magnetic resonance images, * measuring nerve fibres * inferring 3D motion from 2D cinefluoroscopy sequences. The methods and applications represented here encompass the progression of biomedical image analysis from early developments, where computational power became adequate to the challenges posed by biomedical image data, to recent, highly computationally-intensive methods.
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Gill, Mandeep Singh. « Application of software engineering methodologies to the development of mathematical biological models ». Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:35178f3a-7951-4f1c-aeab-390cdd622b05.
Texte intégralRésumé :
Mathematical models have been used to capture the behaviour of biological systems, from low-level biochemical reactions to multi-scale whole-organ models. Models are typically based on experimentally-derived data, attempting to reproduce the observed behaviour through mathematical constructs, e.g. using Ordinary Differential Equations (ODEs) for spatially-homogeneous systems. These models are developed and published as mathematical equations, yet are of such complexity that they necessitate computational simulation. This computational model development is often performed in an ad hoc fashion by modellers who lack extensive software engineering experience, resulting in brittle, inefficient model code that is hard to extend and reuse. Several Domain Specific Languages (DSLs) exist to aid capturing such biological models, including CellML and SBML; however these DSLs are designed to facilitate model curation rather than simplify model development. We present research into the application of techniques from software engineering to this domain; starting with the design, development and implementation of a DSL, termed Ode, to aid the creation of ODE-based biological models. This introduces features beneficial to model development, such as model verification and reproducible results. We compare and contrast model development to large-scale software development, focussing on extensibility and reuse. This work results in a module system that enables the independent construction and combination of model components. We further investigate the use of software engineering processes and patterns to develop complex modular cardiac models. Model simulation is increasingly computationally demanding, thus models are often created in complex low-level languages such as C/C++. We introduce a highly-efficient, optimising native-code compiler for Ode that generates custom, model-specific simulation code and allows use of our structured modelling features without degrading performance. Finally, in certain contexts the stochastic nature of biological systems becomes relevant. We introduce stochastic constructs to the Ode DSL that enable models to use Stochastic Differential Equations (SDEs), the Stochastic Simulation Algorithm (SSA), and hybrid methods. These use our native-code implementation and demonstrate highly-efficient stochastic simulation, beneficial as stochastic simulation is highly computationally intensive. We introduce a further DSL to model ion channels declaratively, demonstrating the benefits of DSLs in the biological domain. This thesis demonstrates the application of software engineering methodologies, and in particular DSLs, to facilitate the development of both deterministic and stochastic biological models. We demonstrate their benefits with several features that enable the construction of large-scale, reusable and extensible models. This is accomplished whilst providing efficient simulation, creating new opportunities for biological model development, investigation and experimentation.
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Tang, Baobao. « Development of Mathematical and Computational Models to Design Selectively Reinforced Composite Materials ». Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10163313.
Texte intégralRésumé :
Different positions of a material used for structures experience different stresses, sometimes at both extremes, when undergoing processing, manufacturing, and serving. Taking the three-point bending as an example, the plate experiences higher stress in the middle span area and lower stress in both sides of the plate. In order to ensure the performance and reduce the cost of the composite, placement of different composite material with different mechanical properties, i.e. selective reinforcement, is proposed.
Very few study has been conducted on selective reinforcement. Therefore, basic understanding on the relationship between the selective reinforcing variables and the overall properties of composite material is still unclear and there is still no clear methodology to design composite materials under different types of loads.
This study started from the analysis of composite laminate under three point bending test. From the mechanical analysis and simulation result of homogeneously reinforced composite materials, it is found that the stress is not evenly distributed on the plate based on through-thickness direction and longitudinal direction. Based on these results, a map for the stress distribution under three point bending was developed. Next, the composite plate was selectively designed using two types of configurations. Mathematical and finite element analysis (FEA) models were built based on these designs. Experimental data from tests of hybrid composite materials was used to verify the mathematical and FEA models. Analysis of the mathematical model indicates that the increase in stiffness of the material at the top and bottom surfaces and middle-span area is the most effective way to improve the flexural modulus in three point bending test. At the end of this study, a complete methodology to perform the selective design was developed.
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Williams, Robert C. « The Development of Mathematical Models for Preliminary Prediction of Highway Construction Duration ». Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/29483.
Texte intégralRésumé :
Knowledge of construction duration is pertinent to a number of project planning functions prior to detailed design development. Funding, financing, and resource allocation decisions take place early in project design development and are significantly influenced by the construction duration. Currently, there is not an understanding of the project factors having a statistically significant relationship with highway construction duration. Other industry sectors have successfully used statistical regression analysis to identify and model the project parameters related to construction duration. While the need is seen for such work in highway construction, there are very few studies which attempt to identify duration-influential parameters and their relationship with the highway construction duration.
This research identifies the project factors, known early in design development, which influence highway construction duration. The factors identified are specific to their respective project types and are those factors which demonstrate a statistically-significant relationship with construction duration. This work also quantifies the relationship between the duration-influential factors and highway construction duration. The quantity, magnitude, and sign of the factor coefficient yields evidence regarding the importance of the project factor to highway construction duration. Finally, the research incorporates the duration-influential project factors and their relationship with highway construction duration into mathematical models which assist in the prediction of construction duration. Full and condensed models are presented for Full-Depth Section and Highway Improvement project types. This research uses statistical regression analysis to identify, quantify, and model these early-known, duration-influential project factors.
The results of this research contribute to the body of knowledge of the sponsoring organization (Virginia Department of Transportation), the highway construction industry, and the general construction industry at large.Ph. D.
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Egeh, Mohamud H. « Modeling corn growth, development and yield under Québec conditions ». Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21546.
Texte intégralRésumé :
The use of crop growth simulation models such asthose incorporated into Decision Support Systems for Agrotechnology Transfer (DSSAT) are useful tools for assessing the impacts of various management practices on crop productivity. The maize growth model of DSSAT is CERES-maize. To evaluate its predictive capability under western Quebec conditions, data on corn (Zea mays L.) yield and above-ground biomass were collected from a field-scale water table management experiment conducted during the 1996 and 1997 growing seasons at St. Emmanuel, Soulanges County, Quebec. The model was calibrated using various crop growth and development data observed during the 1996 growing season. Cultivar-specific coefficients were determined during the calibration. All measured data on phenology, grain yield and biomass collected in 1997 were used for model validation.Validation results showed good agreement between predicted and measured yields. In 1996, the Root Mean Square Error (RMSE) was 0.64 and 0.66 Mg/ha for the free drainage plots with 200 kg/ha N (FD200) and 120 kg/ha N (FD120), respectively. In 1997, the RMSE for FD200 and FD120 were 1.07 and 1.23 Mg/ha respectively. However, the model overpredicted the biomass for 1997, and grain number for both FD200 and FD120 treatments in both years. The mean difference (MD) between simulated and observed biomass at maturity was statistically significant at (P < 0.01) for both treatments. Sensitivity analyses showed that the CERES-Maize model was most sensitive to changes in air temperature. The model was also sensitive to soil water and crop genetic parameters.
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Wong, Chung-yin Philip, et 黃仲賢. « The development of pedestrian flow model ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B48194025.
Texte intégralRésumé :
This dissertation reported on the findings of the characteristics of the pedestrian
flows in Chinese New Year Eve Fair in Hong Kong and, the recommendations to its
crowd control measures. Since most of the pedestrian flow models were developed
for general purposes under normal condition, special models developed specifically
for major events such as bazaars, fairs and festivals in Hong Kong were required to
understand their pedestrian flow patterns. In this dissertation, pedestrian flows in the
Fair were videotaped and data was extracted for calibrating several pedestrian flow
models. These included the conventional models developed by Greenshields,
Greenberg, Pipes-Munjal, Underwood, Drake, Wong et al. and four modifications of
these models for simulating isotropic and bi-directional pedestrian flow scenarios.
The free flow speed of the pedestrians in the Chinese New Year Eve Fair was found
to be around 0.69-0.84 m/s, slower than those identified in other researches. Besides,
the results of these models showed the relationships between walking speed, density
and flow of the pedestrians in the Fair. Also, the effects of bi-directional flow to
pedestrian flows were assessed and quantified. These findings obtained from models
were then used as a basis for formulating crowd control strategy of major events in
Hong Kong.published_or_final_version
Transport Policy and Planning
Master
Master of Arts in Transport Policy and Planning
26
Banerjee, Soumitra. « Development of a procedure for predicting daylighting in square type atrium ». Thesis, Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/80103.
Texte intégralRésumé :
The popularity of the atria after its revival since the 1970's has caught the attention of designers and opened ways for new strategies of energy conservation for large buildings. Early atria were visual statements rather than integrated energy systems. But a growing recognition of the contribution of daylight for energy conservation in atria requires study in greater depth to exploit the potential of the atrium in the use of daylight for energy conservation. Present methods for calculating daylight distribution in conventionally designed buildings are not presently configured to deal with atria.
This study takes advantage of scale model simulation process to develop a mathematical model which will predict daylight distribution in a square atrium under an overcast sky. Data generated from twelve model studies representing thirty six cases were analyzed using statistical methods as a measure to develop the mathematical model.
The mathematical model developed has the ability to predict illumination level on the vertical surface at different floor locations in a square type atrium within the specified limitations. This model is reliable, as the predicted illumination levels have been found to have strong correlation with the values obtained from scale model studies. The mathematical model can be effectively used to assist designers in estimating illumination levels in an atrium and to provide opportunity to test design alternatives while the design is in the preliminary design stage.Master of Architecture
27
Xu, Wenwei. « Development of a Steady-State River Hydrodynamic and Temperature Model Based on CE-QUAL-W2 ». PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1619.
Texte intégralRésumé :
CE-QUAL-W2 is a 2-D hydrodynamic and water quality model that has been applied to reservoirs, lakes, river systems, and estuaries throughout the world. However, when this model is applied for shallow systems, this model requires a long calculation time to maintain numerical stability, compared to applications of reservoirs or deeper river systems.
To solve this problem, a new hydrodynamic and temperature model was built based on the framework of CE-QUAL-W2 but that allows for steady-state hydrodynamic computations. By calculating the hydrodynamics at steady-state, the time step for stability is relaxed and simulations can proceed at much higher time steps. The rest of the model framework is still used for water quality state variables, in this case, temperature. The algorithm used for computing the water surface elevation is Manning's equation.
This thesis study is one part of the Willamette Water 2100 project (Santelmann et al., 2012), which examines hydrological, ecological, and human factors affecting water scarcity in the Willamette River Basin. This study included three stages: (1) Convert six existing CE-QUAL-W2 V3.1 models into a newer version: CE-QUAL-W2 V3.7. (2) Develop the steady-state model code in FORTRAN. (3) Test the steady-state model on three river systems in the Willamette River Basin at Year 2001 and 2002.
The result proved that the steady-state model could reduce the computing time by 90% for river applications, while predicting dynamic river temperature with high accuracy at a two-minute time scale. This new model will be employed to simulate the future of the Willamette River System at a decadal or centennial timescales, addressing river temperature concerns and fish habitat issues.
28
Bouraoui, Faycal. « Development of a continuous, physically-based distributed parameter, nonpoint source model ». Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-10192006-115604/.
Texte intégral
29
Schiefelbein, Jon M. « Prototype development of machine-to-machine operational nephanalysis ». Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Mar%5FSchiefelbein.pdf.
Texte intégral
30
Giannessi, Massimo <1982>. « Development of Clinical Decision Support Systems based on Mathematical Models of Physiological Systems ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2655/1/MGiannessi_Dottorato.pdf.
Texte intégralRésumé :
In the last years of research, I focused my studies on different physiological problems. Together with my supervisors, I developed/improved different mathematical models in order to create valid tools useful for a better understanding of important clinical issues.
The aim of all this work is to develop tools for learning and understanding cardiac and cerebrovascular physiology as well as pathology, generating research questions and developing clinical decision support systems useful for intensive care unit patients.
I. ICP-model Designed for Medical Education
We developed a comprehensive cerebral blood flow and intracranial pressure model to simulate and study the complex interactions in cerebrovascular dynamics caused by multiple simultaneous alterations, including normal and abnormal functional states of auto-regulation of the brain.
Individual published equations (derived from prior animal and human studies) were implemented into a comprehensive simulation program. Included in the normal physiological modelling was: intracranial pressure, cerebral blood flow, blood pressure, and carbon dioxide (CO2) partial pressure. We also added external and pathological perturbations, such as head up position and intracranial haemorrhage.
The model performed clinically realistically given inputs of published traumatized patients, and cases encountered by clinicians. The pulsatile nature of the output graphics was easy for clinicians to interpret.
The manoeuvres simulated include changes of basic physiological inputs (e.g. blood pressure, central venous pressure, CO2 tension, head up position, and respiratory effects on vascular pressures) as well as pathological inputs (e.g. acute intracranial bleeding, and obstruction of cerebrospinal outflow).
Based on the results, we believe the model would be useful to teach complex relationships of brain haemodynamics and study clinical research questions such as the optimal head-up position, the effects of intracranial haemorrhage on cerebral haemodynamics, as well as the best CO2 concentration to reach the optimal compromise between intracranial pressure and perfusion.
We believe this model would be useful for both beginners and advanced learners. It could be used by practicing clinicians to model individual patients (entering the effects of needed clinical manipulations, and then running the model to test for optimal combinations of therapeutic manoeuvres).
II. A Heterogeneous Cerebrovascular Mathematical Model
Cerebrovascular pathologies are extremely complex, due to the multitude of factors acting simultaneously on cerebral haemodynamics.
In this work, the mathematical model of cerebral haemodynamics and intracranial pressure dynamics, described in the point I, is extended to account for heterogeneity in cerebral blood flow. The model includes the Circle of Willis, six regional districts independently regulated by autoregulation and CO2 reactivity, distal cortical anastomoses, venous circulation, the cerebrospinal fluid circulation, and the intracranial pressure-volume relationship.
Results agree with data in the literature and highlight the existence of a monotonic relationship between transient hyperemic response and the autoregulation gain. During unilateral internal carotid artery stenosis, local blood flow regulation is progressively lost in the ipsilateral territory with the presence of a steal phenomenon, while the anterior communicating artery plays the major role to redistribute the available blood flow. Conversely, distal collateral circulation plays a major role during unilateral occlusion of the middle cerebral artery.
In conclusion, the model is able to reproduce several different pathological conditions characterized by heterogeneity in cerebrovascular haemodynamics and can not only explain generalized results in terms of physiological mechanisms involved, but also, by individualizing parameters, may represent a valuable tool to help with difficult clinical decisions.
III. Effect of Cushing Response on Systemic Arterial Pressure.
During cerebral hypoxic conditions, the sympathetic system causes an increase in arterial pressure (Cushing response), creating a link between the cerebral and the systemic circulation.
This work investigates the complex relationships among cerebrovascular dynamics, intracranial pressure, Cushing response, and short-term systemic regulation, during plateau waves, by means of an original mathematical model.
The model incorporates the pulsating heart, the pulmonary circulation and the systemic circulation, with an accurate description of the cerebral circulation and the intracranial pressure dynamics (same model as in the first paragraph). Various regulatory mechanisms are included: cerebral autoregulation, local blood flow control by oxygen (O2) and/or CO2 changes, sympathetic and vagal regulation of cardiovascular parameters by several reflex mechanisms (chemoreceptors, lung-stretch receptors, baroreceptors). The Cushing response has been described assuming a dramatic increase in sympathetic activity to vessels during a fall in brain O2 delivery. With this assumption, the model is able to simulate the cardiovascular effects experimentally observed when intracranial pressure is artificially elevated and maintained at constant level (arterial pressure increase and bradicardia). According to the model, these effects arise from the interaction between the Cushing response and the baroreflex response (secondary to arterial pressure increase). Then, patients with severe head injury have been simulated by reducing intracranial compliance and cerebrospinal fluid reabsorption. With these changes, oscillations with plateau waves developed.
In these conditions, model results indicate that the Cushing response may have both positive effects, reducing the duration of the plateau phase via an increase in cerebral perfusion pressure, and negative effects, increasing the intracranial pressure plateau level, with a risk of greater compression of the cerebral vessels.
This model may be of value to assist clinicians in finding the balance between clinical benefits of the Cushing response and its shortcomings.
IV. Comprehensive Cardiopulmonary Simulation Model for the Analysis of Hypercapnic Respiratory Failure
We developed a new comprehensive cardiopulmonary model that takes into account the mutual interactions between the cardiovascular and the respiratory systems along with their short-term regulatory mechanisms.
The model includes the heart, systemic and pulmonary circulations, lung mechanics, gas exchange and transport equations, and cardio-ventilatory control.
Results show good agreement with published patient data in case of normoxic and hyperoxic hypercapnia simulations.
In particular, simulations predict a moderate increase in mean systemic arterial pressure and heart rate, with almost no change in cardiac output, paralleled by a relevant increase in minute ventilation, tidal volume and respiratory rate.
The model can represent a valid tool for clinical practice and medical research, providing an alternative way to experience-based clinical decisions.
In conclusion, models are not only capable of summarizing current knowledge, but also identifying missing knowledge. In the former case they can serve as training aids for teaching the operation of complex systems, especially if the model can be used to demonstrate the outcome of experiments. In the latter case they generate experiments to be performed to gather the missing data.
31
Giannessi, Massimo <1982>. « Development of Clinical Decision Support Systems based on Mathematical Models of Physiological Systems ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2655/.
Texte intégralRésumé :
In the last years of research, I focused my studies on different physiological problems. Together with my supervisors, I developed/improved different mathematical models in order to create valid tools useful for a better understanding of important clinical issues.
The aim of all this work is to develop tools for learning and understanding cardiac and cerebrovascular physiology as well as pathology, generating research questions and developing clinical decision support systems useful for intensive care unit patients.
I. ICP-model Designed for Medical Education
We developed a comprehensive cerebral blood flow and intracranial pressure model to simulate and study the complex interactions in cerebrovascular dynamics caused by multiple simultaneous alterations, including normal and abnormal functional states of auto-regulation of the brain.
Individual published equations (derived from prior animal and human studies) were implemented into a comprehensive simulation program. Included in the normal physiological modelling was: intracranial pressure, cerebral blood flow, blood pressure, and carbon dioxide (CO2) partial pressure. We also added external and pathological perturbations, such as head up position and intracranial haemorrhage.
The model performed clinically realistically given inputs of published traumatized patients, and cases encountered by clinicians. The pulsatile nature of the output graphics was easy for clinicians to interpret.
The manoeuvres simulated include changes of basic physiological inputs (e.g. blood pressure, central venous pressure, CO2 tension, head up position, and respiratory effects on vascular pressures) as well as pathological inputs (e.g. acute intracranial bleeding, and obstruction of cerebrospinal outflow).
Based on the results, we believe the model would be useful to teach complex relationships of brain haemodynamics and study clinical research questions such as the optimal head-up position, the effects of intracranial haemorrhage on cerebral haemodynamics, as well as the best CO2 concentration to reach the optimal compromise between intracranial pressure and perfusion.
We believe this model would be useful for both beginners and advanced learners. It could be used by practicing clinicians to model individual patients (entering the effects of needed clinical manipulations, and then running the model to test for optimal combinations of therapeutic manoeuvres).
II. A Heterogeneous Cerebrovascular Mathematical Model
Cerebrovascular pathologies are extremely complex, due to the multitude of factors acting simultaneously on cerebral haemodynamics.
In this work, the mathematical model of cerebral haemodynamics and intracranial pressure dynamics, described in the point I, is extended to account for heterogeneity in cerebral blood flow. The model includes the Circle of Willis, six regional districts independently regulated by autoregulation and CO2 reactivity, distal cortical anastomoses, venous circulation, the cerebrospinal fluid circulation, and the intracranial pressure-volume relationship.
Results agree with data in the literature and highlight the existence of a monotonic relationship between transient hyperemic response and the autoregulation gain. During unilateral internal carotid artery stenosis, local blood flow regulation is progressively lost in the ipsilateral territory with the presence of a steal phenomenon, while the anterior communicating artery plays the major role to redistribute the available blood flow. Conversely, distal collateral circulation plays a major role during unilateral occlusion of the middle cerebral artery.
In conclusion, the model is able to reproduce several different pathological conditions characterized by heterogeneity in cerebrovascular haemodynamics and can not only explain generalized results in terms of physiological mechanisms involved, but also, by individualizing parameters, may represent a valuable tool to help with difficult clinical decisions.
III. Effect of Cushing Response on Systemic Arterial Pressure.
During cerebral hypoxic conditions, the sympathetic system causes an increase in arterial pressure (Cushing response), creating a link between the cerebral and the systemic circulation.
This work investigates the complex relationships among cerebrovascular dynamics, intracranial pressure, Cushing response, and short-term systemic regulation, during plateau waves, by means of an original mathematical model.
The model incorporates the pulsating heart, the pulmonary circulation and the systemic circulation, with an accurate description of the cerebral circulation and the intracranial pressure dynamics (same model as in the first paragraph). Various regulatory mechanisms are included: cerebral autoregulation, local blood flow control by oxygen (O2) and/or CO2 changes, sympathetic and vagal regulation of cardiovascular parameters by several reflex mechanisms (chemoreceptors, lung-stretch receptors, baroreceptors). The Cushing response has been described assuming a dramatic increase in sympathetic activity to vessels during a fall in brain O2 delivery. With this assumption, the model is able to simulate the cardiovascular effects experimentally observed when intracranial pressure is artificially elevated and maintained at constant level (arterial pressure increase and bradicardia). According to the model, these effects arise from the interaction between the Cushing response and the baroreflex response (secondary to arterial pressure increase). Then, patients with severe head injury have been simulated by reducing intracranial compliance and cerebrospinal fluid reabsorption. With these changes, oscillations with plateau waves developed.
In these conditions, model results indicate that the Cushing response may have both positive effects, reducing the duration of the plateau phase via an increase in cerebral perfusion pressure, and negative effects, increasing the intracranial pressure plateau level, with a risk of greater compression of the cerebral vessels.
This model may be of value to assist clinicians in finding the balance between clinical benefits of the Cushing response and its shortcomings.
IV. Comprehensive Cardiopulmonary Simulation Model for the Analysis of Hypercapnic Respiratory Failure
We developed a new comprehensive cardiopulmonary model that takes into account the mutual interactions between the cardiovascular and the respiratory systems along with their short-term regulatory mechanisms.
The model includes the heart, systemic and pulmonary circulations, lung mechanics, gas exchange and transport equations, and cardio-ventilatory control.
Results show good agreement with published patient data in case of normoxic and hyperoxic hypercapnia simulations.
In particular, simulations predict a moderate increase in mean systemic arterial pressure and heart rate, with almost no change in cardiac output, paralleled by a relevant increase in minute ventilation, tidal volume and respiratory rate.
The model can represent a valid tool for clinical practice and medical research, providing an alternative way to experience-based clinical decisions.
In conclusion, models are not only capable of summarizing current knowledge, but also identifying missing knowledge. In the former case they can serve as training aids for teaching the operation of complex systems, especially if the model can be used to demonstrate the outcome of experiments. In the latter case they generate experiments to be performed to gather the missing data.
32
Wu, Simon. « Mathematical Modelling of Insulin Resistance Development Caused by Chronic Inflammation ». Thesis, Linköpings universitet, Institutionen för medicinsk teknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-158671.
Texte intégralRésumé :
Obesity has in recent times become a more serious health issue and was estimated to affect over 650 million people world-wide in 2016. Furthermore, the list of obesity-associated diseases is countless, many of which have severe consequences. Type 2 diabetes (T2D) is such a disease, and it was estimated to be over 1.5 million new cases in America alone in 2015. It is thought that insulin resistance development which causes T2D is associated with a low-level chronic inflammation in the adipose tissue. The inflammatory state is caused by the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α) which is secreted by macrophages. To further understand the complexity of the underlying mechanisms of both the adipocytes as well as the macrophages, mathematical models are being developed in the fields of systems biology. However, as of now, no mathematical model has been developed which can explain the association between chronic inflammation and the development of insulin resistance. Because of this, a first model will be presented which is able to describe the mechanisms of insulin resistance development caused by chronic inflammation. The model was fitted to data from intraperitoneal glucose tolerance test in mice and yielded a cost below the threshold of chi-square test, which suggests that the model cannot be rejected. Furthermore, the model was expanded, introducing more complexity in the intracellular cascade reaction of an activated macrophage. Once again, the model was fitted to the same data and yielded a cost below the threshold of chi-square test. Uncertainty tests were made to further validate the models and showed a low uncertainty for both models. These results increase the understanding regarding the association between adipocytes and macrophages, in the role of insulin resistance caused by chronic inflammation. This increased knowledge can help, for instance, in the development of new drugs which are able to prevent the development of insulin resistance and T2D.
33
Taylor, Peter. « Development of compartment models of epileptic spike-wave discharges ». Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/development-of-compartment-models-of-epileptic-spikewave-discharges(4f6f4ff6-f5cd-451f-a806-39590b58468e).html.
Texte intégralRésumé :
Background: Despite the so-called "generalised" nature of many epileptic seizures, patient specific spatio-temporal properties have been shown using imaging data at the macroscopic level of the cortex. Previous computational models have failed to account for spatial heterogeneities at the scale of the entire cortex. Furthermore, one of they key benefits of developing a model is the ability to easily test stimulation protocols. Previous studies of generalised spike-wave (the hallmark of absence epilepsy) have abstracted away from this.METHODSIn this work we develop a set of models of epileptic activity, one of which is at the scale of the entire cortex and incorporates anatomically relevant connectivity from human subjects. A similar model incorporating physiologically relevant thalamocortical circuitry is developed in order to test hypotheses regarding stimulation protocols.RESULTSWe show that the model can account for large-scale spatio-temporal dynamics similar to those seen in epileptic patients. We demonstrate, using the model of thalamocortical interaction, that such a modelling approach can be used for the evaluation of stimulation protocols which are shown to successfully abort the seizure prematurely.CONCLUSIONThis work highlights the importance of computational modelling to support existing data and to make specific predictions regarding testable hypotheses. For example, a stimulus given at the correct time with the correct amplitude will stop the seizure.
34
Li, Feng Engineering & Information Technology Australian Defence Force Academy UNSW. « Development of super resolution techniques for finer scale remote sensing image mapping ». Awarded by:University of New South Wales - Australian Defence Force Academy. Engineering & ; Information Technology, 2009. http://handle.unsw.edu.au/1959.4/44098.
Texte intégralRésumé :
In this thesis, methods for achieving finer scale multi-spectral classification through the use of super resolution (SR) techniques are investigated. A new super resolution algorithm Maximum a Posteriori based on the universal hidden Markov tree model (MAP-uHMT) is developed which can be applied successfully to super-resolve each multi-spectral channel before classification by standard methods. It is believed that this is the first time that a true super resolution algorithm has been applied to multi-spectral classification, and results are shown to be excellent. Image registration is an important step for SR in which misalignment can be measured for each of many low resolution images; therefore, a new and computationally efficient image registration is developed for this particular application. This improved elastic image registration method can deal with a global affine warping and local shift translations based on coarse to fine pyramid levels. The experimental results show that it can provide good registration accuracy in less computational time than comparable methods. Maximum a posteriori (MAP) is adopted to deal with the ill-conditioned problem of super resolution, wherein a prior is constructed based on the universal hidden Markov tree (uHMT) model in the wavelet domain. In order to test this prior for MAP estimation, it is first tested in the simpler and typically ill-conditioned problem of image denoising. Experimental results illustrate that this new image denoising method achieves good performance for the test images. The new prior is then extended to SR. By combining with the new elastic image registration algorithm, MAP-uHMT can super resolve both some natural video frames and remote sensing images. Test results with both synthetic data and real data show that this method achieves super resolution both visually and quantitatively. In order to show that MAPuHMT is also applicable more widely, it is tested on a sequence of long-range surveillance images captured under conditions of atmospheric turbulence distortion. The results suggest that super resolution may have been achieved in this application also.
35
Kim, Changkyun. « Development and evaluation of traffic prediction systems ». Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06062008-164007/.
Texte intégral
36
Al-Zubaidi, Hussein Ali Mahdi. « 3D Hydrodynamic, Temperature, and Water Quality Numerical Model for Surface Waterbodies : Development, Verification, and Field Case Studies ». PDXScholar, 2018. https://pdxscholar.library.pdx.edu/open_access_etds/4500.
Texte intégralRésumé :
Numerical modeling has become a major tool for managing water quality in surface waterbodies such as rivers, lakes, reservoirs, and estuaries. Since the two-dimensional longitudinal/vertical model CE-QUAL-W2 is a well-known model and it has been applied to thousands of waterbodies around the world successfully, its numerical scheme was adapted to develop a new three-dimensional numerical model for simulating hydrodynamics, temperature, and water quality in surface waterbodies. Finite difference approximations were used to solve the fluid dynamic governing equations of continuity, free water surface, momentums, and mass transport. No coordinate transformations were performed and the z-coordinate system has been used. Higher-order schemes (QUICK, QUICKEST, and ULTIMATE QUICKEST) in addition to the UPWIND scheme were used for the advective temperature and mass transport. A novel numerical approach was used for the numerical formulation of the three-dimensional scheme. This approach forced the numerical solution of the free surface equation to be a tri-diagonal matrix form rather than a more computationally intensive penta-diagonal matrix solution. This new approach was done by linking a method called line-by-line with the free water surface numerical solution. Another new approach was that the three-dimensional numerical scheme involved a simultaneous solution of hydrodynamics, temperature, and water quality at every model time level instead of saving the hydrodynamic results to be used later for water quality simulation. Hence, this scheme allowed feedback between the hydrodynamics and water quality every time step. In addition, various unique numerical algorithms were employed from CE-QUAL-W2 such as the W2 turbulence model, selective withdrawal theory, surface heat fluxes, and water quality sources and sinks, making the three-dimensional model built on well-tested algorithms.
To test the model structure and assumptions, an analytical verification was performed by comparing model predictions to known analytical exact solutions test cases. Good agreement was showed by the model for all of these tests. A computation of the volume balance over the simulation period was also incorporated within the model to assess how well the code performed. Sensitivity tests were also made varying bed and wind shear.
The model was also applied to three reservoirs in the USA as field case studies: Lake Chaplain in WA, Laurance Lake in OR, and Cooper Creek Reservoir in OR. The model was validated by comparing the model predictions of water levels, velocities, vertical temperature profiles, and dissolved oxygen with field data. Through these real applications, the numerical predictions of the 3D model showed good agreement with field data based on error statistics. The model results of each field case study were discussed separately. In the Lake Chaplain model application, the study was focused on the importance of the higher-order schemes compared to the first-order UPWIND scheme. The model predictions of temperature were determined by using the UPWIND, QUICK, and QUICKEST scheme and compared with field data. The Error statistics of the model predictions compared to field data were an absolute mean error (AME) of 0.065 m for the water level predictions and an overall AME of 1.62 °C, 1.09 °C, and 1.23 °C for the temperature predictions by using the UPWIND, QUICK, and QUICKEST scheme, respectively. In the Laurance Lake model application, a comparison was performed between the present 3D model and the 2D CE-QUAL-W2. Since the 3D model was build based on CE-QUAL-W2, differences between the two models were evaluated. Error statistics between the model predictions of water level and temperature compared to field data showed that both models were in good agreement with field data. However, the 3D model AME (0.30 m for the water level predictions and 0.48 °C for the temperature predictions) was higher than the 2D model (0.03 m for the water level predictions and 0.42 °C for the temperature predictions). Finally, the Cooper Creek Reservoir case study was done to show the model predictions of temperature and dissolved oxygen. In this application, vertical temperature profiles were covered the entire simulation period in order to show how the model transfer heat between stratification and non- stratification conditions. The model showed good agreement with field data (0.12 m AME for the water level predictions, 1.00 °C overall AME for the temperature predictions, and 1.32 g/m3 overall AME for the dissolved oxygen predictions).
Finally, comparisons were made between CE-QUAL-W2 and the 3D model. The 2D model generally performed better in the tests cases if the model user is unconcerned about lateral impacts. The 3D model is important to use when lateral currents and variation in the lateral dimension are important.
37
McCloud, Nadine. « Model misspecification theory and applications / ». Diss., Online access via UMI:, 2008.
Trouver le texte intégral
38
Lee, Haksu. « Development and performance analysis of a physically based hydrological model incorporating the effects of subgrid heterogeneity ». University of Western Australia. School of Environmental Systems Engineering, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0129.
Texte intégralRésumé :
[Truncated abstract] The balance equations of mass and momentum, defined at the scale of what has been defined as a Representative Elementary Watershed (REW) has been proposed by Reggiani et al. (1998, 1999). While it has been acknowledged that the REW approach and the associated balance equations can be the basis for the development of a new generation of distributed physically based hydrological models, four building blocks have been identified as necessary to transform the REW approach into, at the very least least, a workable modelling framework beyond the theoretical achievements. These are: 1) the development of reasonable closure relations for the mass exchange fluxes within and between various REW sub-regions that effectively parameterize the effects of sub-REW heterogeneity of climatic and landscape properties, 2) the design of numerical algorithms capable of generating numerical solutions of the REW-scale balance equations composed of a set of coupled ordinary differential and algebraic equations for the number of REWs constituting a study catchment and the sub-regions within the REWs, 3) applications of the resulting numerical model to real catchments to assess its performance in the prediction of any specified hydrological variables, and 4) the assessment of the model reliability through estimation of model predictive uncertainty and parameter uncertainty. This thesis is aimed at making substantial progress in developing each of these building blocks. Chapter 1 presents the background and motivation for the thesis, while Chapter 2 summarizes its main contributions. Chapter 3 presents a description of the closure problem that the REW approach faces, and presents and implements various approaches to develop closure relations needed for the completeness of balance equations of the REW approach. ... In addition, Chapter 4 also shows an initial application of CREW to a small catchment, Susannah Brook in the south-west of Western Australia. Chapter 5 presents the application of CREW to two meso-scale catchments in Australia, namely Collie and Howard Springs, located in contrasting climates. Chapter 6 presents results of the estimation of predictive uncertainty and parameter sensitivity through the application of CREW to two catchments in Australia, namely Susannah Brook and Howard Springs, by using the Generalized Likelihood Uncertainty Estimation (GLUE) methodology. Finally, Chapter 7 presents recommendations for future work for the further advancement of the REW approach. Through these exercises this PhD thesis has successfully transformed the REW-scale coupled balance equations derived by Reggiani et al. (1998, 1999) into a new, well tested numerical model blueprint for the development and implementation of distributed, physically based models applicable at the catchment, or REW scale.
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McManus, Christine D. « Development, verification and experimental analysis of high-fidelity mathematical models for control moment gyros ». Thesis, Monterey, California : Naval Postgraduate School, 2011. http://hdl.handle.net/10945/28670.
Texte intégralRésumé :
In the operation of CMGs there exists a concept called “back drive,” which represents a case where the coupling effects of the angular velocity of the body and the angular momentum of the CMG overwhelm the input torque and result in a lack of control. This effect is known but not well documented or studied in the literature. Starting from first principles, this thesis derives the full nonlinear dynamical equations for CMGs. These equations contain significantly more terms than are found in the literature. As a means to understand the implications of these terms, a reduced order model is derived. The full and reduced models are then validated by means of extensive simulations. Finally, experimental verification of the models confirms the finding that the reduced order model provides a reasonably high fidelity for dynamics.
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Correia, Sara Alexandra Chanoca. « Development of improved mathematical models for the design and control of gas-fired furnaces ». Thesis, University of South Wales, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369080.
Texte intégral
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Aguadé, Gorgorió Guim 1991. « Cancer as a complex adaptive system : Mathematical models of tumor ecology, evolution and development ». Doctoral thesis, TDX (Tesis Doctorals en Xarxa), 2021. http://hdl.handle.net/10803/672400.
Texte intégralRésumé :
Despite decades of scientific effort, cancer remains a major cause of death worldwide. Through the accumulation of genome alterations, tumor populations evolve the capacity to circumvent the selective barriers of tissue homeostasis, eventually adapting to resist therapeutic stress. Furthermore, extensive Darwinian evolution is accompanied by an ecological engineering of the surrounding tissue micro-environment together with the alteration of cellular maturation hierarchies. To understand cancer complexity, therefore, we need a picture that spans through the domains of ecology, evolution and development. In an effort to gain understanding of the underlying patterns of treatment resistance, the present PhD thesis introduces a mathematical approach to cancer complexity that takes into account its dynamical nature across these three axes. The resulting modeling endeavor is focused on two major fields of current research: immunotherapy and cancer epigenetics and differentiation, with the aim of providing both treatment design rationale and a comprehensive perspective that merges cancer ecological, evolutionary and developmental complexity.Malgrat dècades d’esforços científics, el càncer continua sent una de les principals causes de mort arreu del món. Mitjançant l’acumulació d’alteracions del genoma, les poblacions tumorals evolucionen la capacitat d’eludir les barreres selectives de l’homeòstasi del teixit, fins al punt d’adaptar-se per resistir l’estrès terapèutic. A més, l’extensa evolució darwiniana s’acompanya d’una enginyeria ecològica del teixit circumdant, juntament amb l’alteració de les jerarquies de maduració cel·lular. Per entendre la complexitat del càncer, per tant, necessitem una imatge que abasti els dominis de l’ecologia, l’evolució i el desenvolupament. En un esforç per comprendre els patrons subjacents de resistència al tractament, al llarg d’aquesta tesi doctoral introduı̈m un enfocament matemàtic de la complexitat del càncer que té en compte la seva naturalesa dinàmica en els tres eixos. L’esforç de modelització resultant se centra en dos grans camps de la investigació actual: la immunoteràpia i l’epigenètica i la diferenciació del càncer, amb l’objectiu d’oferir tant un fonament pel disseny terapèutic com una perspectiva integral que combini la complexitat ecològica, evolutiva i del desenvolupament del càncer.
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Du, Plessis Sydney Charles. « Investigation of process parameters and development of a mathematical model for the purposes of control design and implementation for a wastewater treatment process ». Thesis, Cape Peninsula University of Technology, 2009. http://hdl.handle.net/20.500.11838/1194.
Texte intégralRésumé :
Thesis (DTech (Electrical Engineering))--Cape Peninsula University of Technology, 2009The problem for effective and optimal control of wastewater treabnent plants is very important recently because of the increased requirements to the qualitY of the effluent The activated sludge process is a type of wastewater process characterized with complex dynamics and because of this proper control design and implementation strategies are necessary and important for its operation. Since the early seventies, when a major leap forward was made by the widespread introduction of dissolved oxygen control, little progress has been made. The most critical phase in the solution of any control problem is the modelling stage. The primary building block of any modem control exercise is to construct and identify a model for the system to be controlled. The existing full Activated Sludge Model 1 (ASM1) and especially University of Cape Town (UCT) models of the biological processes in the activated sludge process, called in the thesis biological models, are highly complex because they are characterised with a lot of variables that are difficult to be measured on-line, complex dependencies and nonlinear interconnections between the biological variables, many kinetic parameters that are difficult to be determined, . different time scales for the process dynamics. The project considers reduction of the impact of the complexity of the process model over the methods for control design and proposes a solution to the above difficulties by development of a reduced model with small number of variables, but still with the same characteristics as the original full model for the purposes of real time.
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Johnston, Susan Joy. « The development of an operational management procedure for the South African west coast rock lobster fishery ». Doctoral thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/22567.
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This thesis considers the development of an operational management procedure (OMP) to provide scientific recommendations for commercial TAC for the South African west coast rock lobster (Jasus lalandii) fishery. This fishery has been under considerable stress in recent years as a result of overfishing and low somatic growth rates. Present catch levels, less than 2000 MT, are substantially smaller than levels recorded in the past. The present biomass (above 75mm carapace length) is estimated to be only six percent of the pristine level. At the start of this research, no long-term management strategy for the resource existed. Neither was there any robust, tested, scientific method available for setting the annual TAC for the fishery, which resulted in a time-consuming and unsatisfactory scientific debate each year in developing a series of ad hoc TAC recommendations. The work presented in this thesis is thus aimed at answering two important questions. i) Can an adequate mathematical model be developed as a basis to simulate the resource and its associated fishery? ii) Can a self-correcting robust OMP be developed for the resource? The first phase of this thesis is the development of a size-structured population model of the resource and the associated fishery. A size-structured model is necessary as lobsters are difficult to age and hence most of the data collected are on a size basis. Furthermore, important management issues, such as the legal minimum size which has changed over time, require a model able to take size-structure into account. This model is fitted to a wide range of data from the fishery, including CPUE (catch-per-unit-effort) and catch-at-size information, by maximising a likelihood function. The model is shown to fit reasonably well to all data, and to provide biologically plausible estimates for its six estimable parameters.
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Zhou, Sida. « The Development and Evaluation of Aggregation Methods for Group Pairwise Comparison Judgments ». PDXScholar, 1996. https://pdxscholar.library.pdx.edu/open_access_etds/1222.
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The basic problem of decision making is to choose the best alternative from a set of competing alternatives that are evaluated under conflicting criteria. In general, the process is to evaluate decision elements by quantifying the subjective judgments. The Analytic Hierarchy Process (AHP) provides us with a comprehensive framework for solving such problems. As pointed out by Saaty, AHP "enables us to cope with the intuitive, the rational, and the irrational, all at the same time, when we make multicriteria and multiactor decisions". Furthermore, in most organizations decisions are made collectively, regardless of whether the organization is public or private. It is sometimes difficult to achieve consensus among group members, or for all members of a group to meet. The purpose of this dissertation was two-fold: First, we developed a new aggregation method - Minimum Distance Method (MDM) - to support group decision process and to help the decision makers achieve consensus under the framework of AHP. Second, we evaluated the performance of aggregation methods by using accuracy and group disagreement criteria. The evaluations were performed through simulation and empirical tests. MDM • employs the general distance concept, which is very appealing to the compromise nature of a group decision making. • preserves all of the characteristics of the functional equations approach proposed by Aczel and Saaty. • is based on a goal programming model, which is easy to solve by using a commercial software such as LINDO. • provides the weighted membership capability for participants. • allows for sensitivity analysis to investigate the effect of importance levels of decision makers in the group. The conclusions include the following: • Simulation and empirical tests show that the two most important factors in the aggregation of pairwise comparison judgments are the probability distribution of error terms and the aggregation method. • Selection of the appropriate aggregation method can result in significant improvements in decision quality. • The MDM outperforms the other aggregation methods when the pairwise comparison judgments have large variances. • Some of the prioritization methods, such as EV[AA'], EV[A'A], arithmetic and geometric mean of EV[AA'] and EV[A'A], can be dropped from consideration due to their poor performance
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Lau, Mei-wan, et 劉美雲. « On the early development of dispersion in flow through a tube with wall reactions ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B38994859.
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Yin, Jun, et 尹俊. « A continuum modeling approach to transport emission problems ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46603499.
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Rios-Estepa, Rigoberto. « Unraveling the regulation of mint monoterpene biosynthesis development and experimental testing of kinetic mathematical models / ». Pullman, Wash. : Washington State University, 2008. http://www.dissertations.wsu.edu/Dissertations/Fall2008/r_rios-estepa_111008.pdf.
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Thesis (Ph. D.)--Washington State University, December 2008.Title from PDF title page (viewed on Jan. 15, 2009). "The Gene and Linda Voiland School of Chemical Engineering and Bioengineering." Includes bibliographical references.
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Lund, Ohlsson Marie. « New methods for movement technique development in cross-country skiing using mathematical models and simulation ». Licentiate thesis, Sundsvall : Mittuniversitetet, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-10041.
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Yin, Xiaopeng 1963. « Endogenous growth, international trade and dynamics ». Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37914.
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This PhD. dissertation consists of three essays to fill some gaps in the recent research in international trade and endogenous growth theory. The first essay explores the dynamic effect of interaction of research and development (R&D) activities among countries on endogenous economic growth. It attempts to fill the gap between the current endogenous growth research focused on independent R&D activities and decision-making in the international competition and the interdependent R&D competition in reality. This paper finds that the growth rates, welfare, and investment on R&D in the world do differ between independent R&D activity and interdependent R&D activities among countries. The welfare for each country in the open-loop Nash equilibrium is higher than that of the Markov-perfect Nash equilibrium, and both are lower than that in the cooperative game. The model shows that the ability to commit turns out to make every country better off. The interesting results are that when an increase in the number of countries does increase the growth rate in the open-loop Nash equilibrium, it is very possible to have the negative effect on the growth rate in the Markov-perfect equilibrium. Particularly, the model shows that the tendency of free-ride rises with more countries in the competition. The more general models with durable physical capital, and with the endogenous rate of time preference following Uzawa-Epstein tradition, also prove these conclusions.The second essay turns to the Samuelson-Diamond overlapping generation paradigm, a finite-horizon overlapping generations model with education proposed by Michel (1993). The focus is shifted to the effect of trade on growth. It turns out that when trade affects the formation of human capital, endogenous growth is possible even in the simplest economy with a single sector and constant returns to scale technologies, which is opposite from Boldrin's (1992) and Jones and Manuelli's (1992) results.
While the existing theory of trade under oligopolistic competition is mostly static in nature, the third essay fills this gap by modeling international trade under oligopoly in a dynamic setting. This essay adopts the dynamics in the model provided by allowing the demand curve to shift over time as a result of "habit formation". It shows that when the importing country is committing to a policy of voluntary import expansions (VIEs), in the certain condition (i.e. k > 1), VIEs can improve the global welfare, the welfare of the importing country, and the profit of both firms. So, in a sense, voluntary import expansion is truly voluntary.
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Wilson, Amanda C. « Equivalent initial flaw size model development for turbine blades using in-service data ». Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/20006.
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