Dissertations / Theses on the topic 'Parameter'
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Aristizabal, Rodrigo J. "Estimating the Parameters of the Three-Parameter Lognormal Distribution." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/575.
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The three-parameter lognormal distribution is widely used in many areas of science. Some modifications have been proposed to improve the maximum likelihood estimator. In some cases, however, the modified maximum likelihood estimates do not exist or the procedure encounters multiple estimates.
The purpose of this research is focused on estimating the threshold or location parameter , because when is known, then the other two estimated parameters are obtained from the first two MLE equations. In this research, a method for constructing confidence intervals, confidence limits, and point estimator for the threshold parameter is proposed. Monte-Carlo simulation, bisection method, and SAS/IML were used to accomplish this objective. The bias of the point estimator and mean square error (MSE) criteria were used throughout extensive simulation to evaluate the performance of the proposed method. The result shows that the proposed method can provide quite accurate estimates.
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Nielsen, Mark A. "Parameter Estimation for the Two-Parameter Weibull Distribution." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2509.
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The Weibull distribution, an extreme value distribution, is frequently used to model survival, reliability, wind speed, and other data. One reason for this is its flexibility; it can mimic various distributions like the exponential or normal. The two-parameter Weibull has a shape (γ) and scale (β) parameter. Parameter estimation has been an ongoing search to find efficient, unbiased, and minimal variance estimators. Through data analysis and simulation studies, the following three methods of estimation will be discussed and compared: maximum likelihood estimation (MLE), method of moments estimation (MME), and median rank regression (MRR). The analysis of wind speed data from the TW Daniels Experimental Forest are used for this study to test the performance and flexibility of the Weibull distribution.
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Chen, Lu. "Computerized evaluation of parameters for HEMT DC and microwave S parameter models." Ohio : Ohio University, 1995. http://www.ohiolink.edu/etd/view.cgi?ohiou1179518920.
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Alana, Jorge Enrique. "Optimal measurement locations for parameter estimation of distributed parameter systems." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/optimal-measurement-locations-for-parameter-estimation-of-distributed-parameter-systems(fffa31d8-2b19-434b-a2b6-7809e314bb55).html.
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Identifying the parameters with the largest influence on the predicted outputs of a model revealswhich parameters need to be known more precisely to reduce the overall uncertainty on themodel output. A large improvement of such models would result when uncertainties in the keymodel parameters are reduced. To achieve this, new experiments could be very helpful,especially if the measurements are taken at the spatio-temporal locations that allow estimate the parameters in an optimal way. After evaluating the methodologies available for optimal sensor location, a few observations were drawn. The method based on the Gram determinant evolution can report results not according to what should be expected. This method is strongly dependent of the sensitivity coefficients behaviour. The approach based on the maximum angle between subspaces, in some cases, produced more that one optimal solution. It was observed that this method depends on the magnitude of outputs values and report the measurement positions where the outputs reached their extrema values. The D-optimal design method produces number and locations of the optimal measurements and it depends strongly of the sensitivity coefficients, but mostly of their behaviours. In general it was observed that the measurements should be taken at the locations where the extrema values (sensitivity coefficients, POD modes and/or outputs values) are reached. Further improvements can be obtained when a reduced model of the system is employed. This is computationally less expensive and the best estimation of the parameter is obtained, even with experimental data contaminated with noise. A new approach to calculate the time coefficients belonging to an empirical approximator based on the POD-modes derived from experimental data is introduced. Additionally, an artificial neural network can be used to calculate the derivatives but only for systems without complex nonlinear behaviour. The latter two approximations are very valuable and useful especially if the model of the system is unknown.
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Wandel, Simon. "Multi-parameter evidence synthesis /." Bern : [s.n.], 2009. http://www.zb.unibe.ch/download/eldiss/09wandel_s.pdf.
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Germund, Ingo. "Morphometrische Parameter des Radiuskopfes /." Köln, 2008. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000253310.
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Shin, Dong Ryong. "Parameter plane design method." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/26148.
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Lui, Jerome C. (Jerome Chun Lung). "Automated MOSFET parameter extraction." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36583.
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Jentschke, Christina. "Analyseteil 1: Elementare Parameter." Der Komponist Jan / Johann Zach aus zeitgenössischer und späterer Perspektive, 2007. https://slub.qucosa.de/id/qucosa%3A75309.
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Die vorliegende Arbeit wurde vom Fachbereich 2 (Lehrämter, Wissenschaft und Komposition) an der Hochschule für Musik und Darstellende Kunst Frankfurt am Main als Dissertation zur Erlangung des Grades einer Doktorin oder eines Doktors der Philosophie angenommen.
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Sundström, Dennis. "Automatized GARCH parameter estimation." Thesis, KTH, Matematisk statistik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-213725.
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This paper is about automatizing parameter estimation of GARCH type conditional volatility models for the sake of using it in an automated risk monitoring system. Many challenges arise with this task such as guaranteeing convergence, being able to yield reasonable results regardless of the quality of the data, accuracy versus speed of the algorithm to name a few. These problems are investigated and a robust framework for an algorithm is proposed, containing dimension reducing and constraint relaxing parameter space transformations with robust initial values. The algorithm is implemented in java with two models, namely the GARCH and gjr-GARCH model. By using real market data, performance of the algorithm are tested with various in-sample and out-of-sample measures, including backtesting of the widely used risk measure Value-at-Risk. The empirical studies conclude that the more complex gjr-sGARCH model with the conditional student’s t distribution was found to yield the most accurate results. However for the purpose of this paper the GARCH orgjr-GARCH seems more appropriate.Denna uppsats undersöker möjligheten att automatisera approximationen av GARCH parametrar, där syftet är att använda algoritmen till ett automatiserat riskhanteringssystem. Med detta uppstår flera utmaningar som att garantera konvergens, kunna erhålla rimliga resultat oavsett datakvalitet, avvägning mellan algoritmens snabbhet och precision för att nämna några. Uppsatsen undersöker dessa problem och föreslår ett robust ramverk för en algoritm som innehåller transformationer av parameterrymden. Där dessa transformationer reducerar dimensionen av problemet samt reducerar antalet randvillkor. Algoritmen är implementerad i java med två modeller, GARCH och gjr-GARCH. Vidare så är algoritmen testad genom att använda riktig marknadsdata, där olika metoder använts för att utvärdera algoritmen. Modellerna som används backtestas på historisk data och det empiriska resultatet av detta talar för att gjr-sGARCH modellen med student’s t fördelning levererar noggrannast resultat. Det är dock den mest komplexa modellen som används i denna uppsats och för denna uppsats ändamål anses GARCH eller gjr-GARCH modellerna mer passande.
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Wang, Feng. "Robust control of quasi-linear parameter-varying L2 point formation flying with uncertain parameters." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/6933.
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Robust high precision control of spacecraft formation flying is one of the most important techniques required for high-resolution interferometry missions in the complex deep-space environment. The thesis is focussed on the design of an invariant stringent performance controller for the Sun-Earth L2 point formation flying system over a wide range of conditions while maintaining system robust stability in the presence of parametric uncertainties. A Quasi-Linear Parameter-Varying (QLPV) model, generated without approximation from the exact nonlinear model, is developed in this study. With this QLPV form, the model preserves the transparency of linear controller design while reflecting the nonlinearity of the system dynamics. The Polynomial Eigenstructure Assignment (PEA) approach used for Linear Time-Invariant (LTI) and Linear Parameter-Varying (LPV ) models is extended to use the QLPV model to perform a form of dynamic inversion for a broader class of nonlinear systems which guarantees specific system performance. The resulting approach is applied to the formation flying QLPV model to design a PEA controller which ensures that the closed-loop performance is independent of the operating point. Due to variation in system parameters, the performance of most closed-loop systems are subject to model uncertainties. This leads naturally to the need to assess the robust stability of nonlinear and uncertain systems. This thesis presents two approaches to this problem, in the first approach, a polynomial matrix method to analyse the robustness of Multiple-Input and Multiple-Output (MIMO) systems for an intersectingD-region,which can copewith time-invariant uncertain systems is developed. In the second approach, an affine parameterdependent Lyapunov function based Linear Matrix Inequality (LMI) condition is developed to check the robust D-stability of QLPV uncertain systems.
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Schlegel, Patrick [Verfasser]. "Assessment of clinical voice parameters and parameter reduction using supervised learning approaches / Patrick Schlegel." Düren : Shaker, 2020. http://d-nb.info/1213473071/34.
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Zhang, Xiping. "Parameter-Dependent Lyapunov Functions and Stability Analysis of Linear Parameter-Dependent Dynamical Systems." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5270.
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The purpose of this thesis is to develop new stability conditions for several linear dynamic systems, including linear parameter-varying (LPV), time-delay systems (LPVTD), slow LPV
systems, and parameter-dependent linear time invariant (LTI) systems. These stability conditions are less conservative and/or computationally easier to apply than existing ones.
This dissertation is composed of four parts. In the first part of this thesis, the complete stability domain for LTI parameter-dependent (LTIPD) systems is synthesized by extending existing results in the literature. This domain is calculated through a guardian map which involves the determinant of the Kronecker sum of a matrix with itself. The stability domain is
synthesized for both single- and multi-parameter dependent LTI systems. The single-parameter case is easily computable, whereas the multi-parameter case is more involved. The determinant of the
bialternate sum of a matrix with itself is also exploited to reduce the computational complexity.
In the second part of the thesis, a class of parameter-dependent Lyapunov functions is proposed, which can be used to assess the stability properties of single-parameter LTIPD systems in a non-conservative manner. It is shown
that stability of LTIPD systems is equivalent to the existence of a Lyapunov function of a polynomial type (in terms of the parameter) of known, bounded degree satisfying two matrix inequalities. The bound of polynomial degree of the Lyapunov functions is then reduced by taking advantage of the fact that the Lyapunov matrices are symmetric. If the matrix multiplying the parameter is not full rank, the polynomial order
can be reduced even further. It is also shown that checking the feasibility of these matrix
inequalities over a compact set can be cast as a convex optimization problem. Such Lyapunov functions and stability conditions for affine single-parameter LTIPD systems are then generalized to single-parameter polynomially-dependent LTIPD systems and affine multi-parameter LTIPD systems.
The third part of the thesis provides one of the first attempts to derive computationally tractable criteria for analyzing the stability of LPV time-delayed systems. It presents both
delay-independent and delay-dependent stability conditions, which are derived using appropriately selected Lyapunov-Krasovskii functionals. According to the system parameter dependence, these functionals can be selected to obtain increasingly non-conservative results. Gridding techniques may be used to cast these tests as Linear Matrix Inequalities (LMI's). In cases when
the system matrices depend affinely or quadratically on the parameter, gridding may be avoided. These LMI's can be solved efficiently using available software. A numerical example of a
time-delayed system motivated by a metal removal process is used to demonstrate the theoretical results.
In the last part of the thesis, topics for future
investigation are proposed. Among the most interesting avenues for research in this context, it is proposed to extend the existing stability analysis results to controller synthesis, which will be based on the same Lyapunov functions used
to derive the nonconservative stability conditions. While designing the dynamic ontroller for linear and parameter-dependent systems, it is desired to take the advantage of the rank deficiency of the system matrix multiplying the parameter such that the controller is of lower dimension, or rank deficient without sacrificing the performance of closed-loop systems.
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Ramaisa, Motlalepula. "Inferring congestion from delay and loss characteristics using parameters of the three-parameter Weibull distribution." Diss., Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-08282007-112036.
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Blanchard, Emmanuel. "Polynomial Chaos Approaches to Parameter Estimation and Control Design for Mechanical Systems with Uncertain Parameters." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/26727.
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Mechanical systems operate under parametric and external excitation uncertainties. The polynomial chaos approach has been shown to be more efficient than Monte Carlo approaches for quantifying the effects of such uncertainties on the system response. This work uses the polynomial chaos framework to develop new methodologies for the simulation, parameter estimation, and control of mechanical systems with uncertainty.
This study has led to new computational approaches for parameter estimation in nonlinear mechanical systems. The first approach is a polynomial-chaos based Bayesian approach in which maximum likelihood estimates are obtained by minimizing a cost function derived from the Bayesian theorem. The second approach is based on the Extended Kalman Filter (EKF). The error covariances needed for the EKF approach are computed from polynomial chaos expansions, and the EKF is used to update the polynomial chaos representation of the uncertain states and the uncertain parameters. The advantages and drawbacks of each method have been investigated.
This study has demonstrated the effectiveness of the polynomial chaos approach for control systems analysis. For control system design the study has focused on the LQR problem when dealing with parametric uncertainties. The LQR problem was written as an optimality problem using Lagrange multipliers in an extended form associated with the polynomial chaos framework. The solution to the Hâ problem as well as the H2 problem can be seen as extensions of the LQR problem. This method might therefore have the potential of being a first step towards the development of computationally efficient numerical methods for Hâ design with parametric uncertainties.
I would like to gratefully acknowledge the support provided for this work under NASA Grant NNL05AA18A.Ph. D.
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Svensson, Emil. "Parameter estimation of biological pathways." Thesis, Linköping University, Department of Electrical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8430.
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To determine parameter values for models of reactions in the human body, like the glycolysis, good methods of parameter estimation are needed. Those models are often non-linear and estimation of the parameters can be very time consuming if it is possible at all. The goal of this work is to test different methods to improve the calculation speed of the parameter estimation of an example system. If the parameter estimation speed for the example system can be improved it is likely that the method could also be useful for systems similar to the example system.
One approach to improve the calculation speed is to construct a new cost function whose evaluation does not require any simulation of the system. Simulation free parameter estimation can be much quicker than using simulations to evaluate the cost function since the cost function is evaluated many times. Also a modication of the simulated annealing optimization method has been implemented and tested.
It turns out that some of the methods significantly reduced the time needed for the parameter estimations. However the quick methods have disadvantages in the form of reduced robustness. The most successful method was using a spline approximation together with a separation of the model into several submodels, and repeated use of the simulated annealing optimization algorithm to estimate the parameters.
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Shlapunov, Alexander, and Nikolai Tarkhanov. "Mixed problems with a parameter." Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2008/2667/.
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Let X be a smooth n -dimensional manifold and D be an open connected set in X with smooth boundary ∂D. Perturbing the Cauchy problem for an elliptic system Au = f in D with data on a closed set Γ ⊂ ∂D we obtain a family of mixed problems depending on a small parameter ε > 0. Although the mixed problems are subject to a non-coercive boundary condition on ∂DΓ in general, each of them is uniquely solvable in an appropriate Hilbert space DT and the corresponding family {uε} of solutions approximates the solution of the Cauchy problem in DT whenever the solution exists. We also prove that the existence of a solution to the Cauchy problem in DT is equivalent to the boundedness of the family {uε}. We thus derive a solvability condition for the Cauchy problem and an effective method of constructing its solution. Examples for Dirac operators in the Euclidean space Rn are considered. In the latter case we obtain a family of mixed boundary problems for the Helmholtz equation.
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Bejugam, Santosh. "Tremor quantification and parameter extraction." Thesis, Mittuniversitetet, Institutionen för informationsteknologi och medier, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-16021.
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Tremor is a neuro degenerative disease causing involuntary musclemovements in human limbs. There are many types of tremor that arecaused due to the damage of nerve cells that surrounds thalamus of thefront brain chamber. It is hard to distinguish or classify the tremors asthere are many reasons behind the formation of specific category, soevery tremor type is named behind its frequency type. Propermedication for the cure by physician is possible only when the disease isidentified.Because of the argument given in the above paragraph, there is a needof a device or a technique to analyze the tremor and for extracting theparameters associated with the signal. These extracted parameters canbe used to classify the tremor for onward identification of the disease.There are various diagnostic and treatment monitoring equipment areavailable for many neuromuscular diseases. This thesis is concernedwith the tremor analysis for the purpose of recognizing certain otherneurological disorders. A recording and analysis system for human’stremor is developed.The analysis was performed based on frequency and amplitudeparameters of the tremor. The Fast Fourier Transform (FFT) and higherorderspectra were used to extract frequency parameters (e.g., peakamplitude, fundamental frequency of tremor, etc). In order to diagnosesubjects’ condition, classification was implemented by statisticalsignificant tests (t‐test).
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Marcinkevicius, Tadas. "DRAM BASED PARAMETER DATABASE OPTIMIZATION." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-100332.
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This thesis suggests an improved parameter database implementation for one of Ericsson products. The parameter database is used during the initialization of the system as well as during the later operation. The database size is constantly growing because the parameter database is intended to be used with different hardware configurations. When a new technology platform is released, multiple revisions with additional features and functionalities are later created, resulting in introduction of new parameters or changes to their values. Ericsson provides support for old and new products. The entire parameter database is currently stored in DRAM memory as a hash map. Therefore an optimal parameter database implementation should have low memory footprint. The search speed and initialization speed for the target system are also important to allow high system availability and low downtime, since a reboot is a common fix for many problems. As many optimizations have to consider memory size – speed tradeoff, it has been decided to give preference to reducing memory footprint. This research seeks to: Analyze data-structures suitable for parameter database implementation (Hash map, Sparsehash, Judy hash, Binary search tree, Treap, Skip List, AssocVector presorted using std::map, Burst trie). Propose the best data-structure in terms of used memory area and speed. If possible, further optimize it for database size in memory and access speed. Create a prototype implementation. Test the performance of the new implementation. The results indicate that a more compact database implementation can be achieved using alternative data structures such as Presorted AssocVector an Sparsehash, however some search speed and build speed is lost when using these data structures instead of the original Gnu Hash Map implementation.
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Nordström, Didrik. "Declarative modelling of parameter setting." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171087.
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The parameter setting problem is part of a complex, automated process for customizing Scania's products; primarily trucks and buses. The problem is modelled as a stateless, acyclic graph of pure functions and variables. A subset of a deterministic, concurrent, demand-driven, declarative programming model is implemented under the Microsoft .NET framework. The implementation is evaluated based on suitability for solving the parameter setting problem, computational performance and general applicability within the organization. It is concluded that the model reduces the complexity of the parameter setting problem, mainly due to demand-driven (lazy) execution. The implementation scales as expected on sequential programs in time and memory with respect to input size. Parallel programs benefit partly from parallelism but bottlenecks in the .NET framework seem to limit the speedup. The general applicability of the programming model within the organization is potentially high and there are many extensions that can be added in the future, such as constraint programming.Parametersättning är en del av en komplex, automatiserad process för att specialanpassa Scanias produkter – primärt lastbilar och bussar. Problemet är modellerat som en tillståndslös acyklisk graf av rena funktioner och variabler. En deterministisk, parallel, behovstyrd deklarativ programmeringsmodell har implementeras under Microsoft .NET-ramverket. Implementationen utvärderas utifrån lämplighet för parametersättning, prestanda och generell nytta inom organisationen. Modellen lyckas med att reducera komplexiteten för parametersättning, primärt tack vare behovstyrd (lat) exekvering. Implementationen skalar i både tid och minne i enlighet med förväntningarna för sekventiella program. Parallella program har delvis nytta av multipla processorkärnor men flaskhalsar i .NET-ramverket verkar begränsa prestandan. Programmeringsmodellens generella nytta inom organisationen är potentiellt hög och det finns många tillbyggnader som kan läggas till i framtiden, såsom villkorsprogrammering.
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Stewart, Osamuyimen Thompson. "The serial verb construction parameter." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0021/NQ44600.pdf.
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Law, Nga Lam. "Parameter-free adaptive genetic algorithm /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202007%20LAW.
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Lee, Joonyong. "Parameter estimation for unsaturated flow." 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:1442901.
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Niedermeier, Rolf. "Invitation to fixed-parameter algorithms /." Oxford [u.a.] : Oxford Univ. Press, 2006. http://www.gbv.de/dms/ilmenau/toc/500666768niede.PDF.
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Hamilton, Brian. "Non-stationary sinusoidal parameter estimation." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106316.
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Parameter estimation is an essential step in sinusoidal modelling for additive sound synthesis, speech synthesis, and digital audio effects. This thesis investigates parameter estimation for a non-stationary sinusoidal signal model with a polynomial log-amplitude and a polynomial phase up to a given order. Two existing parameter estimation methods are investigated (the Reassignment Method and the Derivative Method) for the non-stationary sinusoidal model up to second-order. These methods are related to time-frequency reassignment for the spectrogram and they are shown to be biased by the effect of second-order log-amplitude and second-order phase modulations on spectrogram reassignment. Three generalized parameter estimations methods (the Distribution Derivative Method, the Generalized Reassignment Method, and the Generalized Derivative Method) that provide unbiased estimators for the non-stationary sinusoidal model up to any order are presented and formulated in a new, unified framework. These generalized methods are also related to spectrogram reassignment and it is shown that they correct the bias present in the second-order methods. Practical comparisons of the generalized methods and the theoretical lower limits of estimator performance, the Cramér-Rao bounds, are carried out in experimental tests with synthetic signals. For the sake of completeness, another state of the art method (the Quadratic Interpolated Fast Fourier Transform method) based the Fourier transform of a Gaussian windowed signal, is extended to second-order log-amplitude modulation and tested along with the generalized methods.L'estimation des paramètres est une étape essentielle de la modélisation sinusoïdale dans des domaines tels que la synthèse sonore additive, la synthèse vocale, et les effets audio numériques. Cette thèse examine ce problème dans le cas d'un modèle de signal sinusoïdal non-stationnaire, dont l'amplitude logarithmique et la phase sont représentées par deux polynômes d'ordre inférieur ou égal à un entier donné. Deux méthodes d'estimation d'un modèle non-stationnaire d'ordre inférieur ou égal à deux (méthode par réallocation et méthode de la dérivée), toutes deux reliées à la réallocation du spectrogramme dans le domaine temps-fréquence, sont étudiées. Nous démontrons la présence d'un biais d'estimation, conséquence des modulations conjointes au second ordre, d'amplitude logarithmique et de phase, du spectrogramme réalloué.Sont ensuite présentées et reformulées dans un formalisme unificateur trois méthodes d'estimation généralisées (la méthode des distributions dérivées, la méthode de réallocation généralisée, et la méthode de la dérivée généralisée). Nous démontrons que ces méthodes, également liées au spectrogramme réalloué, fournissent des estimateurs non-biaisés pour le modèle sinusoïdal non-stationnaire à tous les ordres et corrigent le biais existant dans le cas des méthodes à l'ordre deux. La comparaison pratique de ces méthodes généralisées, ainsi que l'établissement de la limite théorique de leur performance, sous forme de bornes de Cramér-Rao, sont établies lors de tests expérimentaux sur des signaux synthétiques. Par souci d'exhaustivité, une autre méthode d'estimation de paramètres du modèle sinusoïdal complétant l'état de l'art du domaine (la méthode par transformée de Fourier rapide avec interpolation quadratique), fondée sur la transformée de Fourier d'un signal pondéré par une fenêtre Gaussienne, est étudiée. Après avoir étendu sa formulation au modèle d'amplitude logarithmique d'ordre deux nous la testons et la comparons aux méthodes généralisées dans les mêmes conditions que précédemment.
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Armour, Bernard. "Structured covariance autoregressive parameter estimation." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59559.
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In this thesis, the problem of estimating the autoregressive (AR) parameters of a wide sense stationary process is studied for the application of spectrum estimation of short data records. The approach taken is to first estimate a structured covariance matrix satisfying an optimality criterion and then map the estimate into the AR parameter estimates. Most covariance estimators are based on a least squares prediction error criterion. The new approach taken in this thesis is the use of a maximum likelihood (ML) criterion to obtain better covariance estimates. Both approximate and exact ML algorithms are developed based on an iterative Newton-Raphson technique to maximize the loglikelihood functions. Testing reveals the symmetric centro-symmetric structured covariance provides superior estimates in comparison to the Toeplitz structure and that the exact ML AR parameter estimates are among the lowest variance. Full comparison of the ML and popular AR spectrum estimation techniques is included.
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Davidson, Colin H. "Caging with one-parameter grippers." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301807.
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Abu-Shanab, Reman Yousif. "Information Inequalities and Parameter Estimation." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505090.
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Al-Ballaa, Hind Rasheed. "Diagnosis via Qualitative parameter estimation." Thesis, University of Aberdeen, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493495.
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This thesis presents an approach for qualitative model based fault diagnosis via parameter estimation. Estimating parameters qualitatively in this research is based on the relationships among involved qualitative quantities. To maintain the consistency of ordinal relationships an inequality reasoner is developed. Existing inequality reasoners (or commonly in the AI community referred to as quantity lattices) infer relationships between quantities involved in a system (qualitative or quantitative) based on the real values associated with them. The novel feature of our inequality reasoner is that it infers and maintains relationships among pure qualitative quantities. Inferring ordinal relationships between sign based quantities removes the traditional drawback of qualitative domain, the lack of discriminating power.
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Manchu, Sreenivasarao. "Parameter Identification for Mechanical Joints." Thesis, Blekinge Tekniska Högskola, Avdelningen för maskinteknik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-4309.
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All but the simplest physical systems contains mechanical joints. The behavior of these joints is sometimes the dominant factor in over all system behavior. The potential for occurence of microslip and macroslip normally makes the behavior of joints non-linear. Accurate modeling of joints requires a non-linear ramework. As clamping pressures are typically random ad variable, the behavior of the joints becomes random. Joint geometries are random along with other unknowns of the joints. Two different methods for measuring the energy dissipation are explained. In the experimental method, the energy dissipation of a non-linear joint is calculated from the slope of the envelope of the time response of acceleration. The simulation work is carried out by considering a smooth hysteresis model with the help of Matlab programming. Finally, the parameters are extracted for a specific non-linear system by comparing analytical and experimental results.0736988322
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Ollikainen, Kati. "PARAMETER ESTIMATION IN LINEAR REGRESSION." Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4138.
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Today increasing amounts of data are available for analysis purposes and often times for resource allocation. One method for analysis is linear regression which utilizes the least squares estimation technique to estimate a model's parameters. This research investigated, from a user's perspective, the ability of linear regression to estimate the parameters' confidence intervals at the usual 95% level for medium sized data sets. A controlled environment using simulation with known data characteristics (clean data, bias and or multicollinearity present) was used to show underlying problems exist with confidence intervals not including the true parameter (even though the variable was selected). The Elder/Pregibon rule was used for variable selection. A comparison of the bootstrap Percentile and BCa confidence interval was made as well as an investigation of adjustments to the usual 95% confidence intervals based on the Bonferroni and Scheffe multiple comparison principles. The results show that linear regression has problems in capturing the true parameters in the confidence intervals for the sample sizes considered, the bootstrap intervals perform no better than linear regression, and the Scheffe method is too wide for any application considered. The Bonferroni adjustment is recommended for larger sample sizes and when the t-value for a selected variable is about 3.35 or higher. For smaller sample sizes all methods show problems with type II errors resulting from confidence intervals being too wide.Ph.D.
Department of Industrial Engineering and Management Systems
Engineering and Computer Science
Industrial Engineering and Management Systems
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Dyachenko, Evgeniya. "Elliptic problems with small parameter." Phd thesis, Universität Potsdam, 2014. http://opus.kobv.de/ubp/volltexte/2014/7205/.
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In this thesis we consider diverse aspects of existence and correctness of asymptotic solutions to elliptic differential and pseudodifferential equations.
We begin our studies with the case of a general elliptic boundary value problem in partial derivatives. A small parameter enters the coefficients of the main equation as well as into the boundary conditions. Such equations have already been investigated satisfactory, but there still exist certain theoretical deficiencies. Our aim is to present the general theory of elliptic problems with a small parameter. For this purpose we examine in detail the case of a bounded domain with a smooth boundary. First of all, we construct formal solutions as power series in the small parameter. Then we examine their asymptotic properties. It suffices to carry out sharp two-sided emph{a priori} estimates for the operators of boundary value problems which are uniform in the small parameter. Such estimates failed to hold in functional spaces used in classical elliptic theory. To circumvent this limitation we exploit norms depending on the small parameter for the functions defined on a bounded domain. Similar norms are widely used in literature, but their properties have not been investigated extensively. Our theoretical investigation shows that the usual elliptic technique can be correctly carried out in these norms. The obtained results also allow one to extend the norms to compact manifolds with boundaries. We complete our investigation by formulating algebraic conditions on the operators and showing their equivalence to the existence of a priori estimates.
In the second step, we extend the concept of ellipticity with a small parameter to more general classes of operators. Firstly, we want to compare the difference in asymptotic patterns between the obtained series and expansions for similar differential problems. Therefore we investigate the heat equation in a bounded domain with a small parameter near the time derivative. In this case the characteristics touch the boundary at a finite number of points. It is known that the solutions are not regular in a neighbourhood of such points in advance. We suppose moreover that the boundary at such points can be non-smooth but have cuspidal singularities. We find a formal asymptotic expansion and show that when a set of parameters comes through a threshold value, the expansions fail to be asymptotic.
The last part of the work is devoted to general concept of ellipticity with a small parameter. Several theoretical extensions to pseudodifferential operators have already been suggested in previous studies. As a new contribution we involve the analysis on manifolds with edge singularities which allows us to consider wider classes of perturbed elliptic operators. We examine that introduced classes possess a priori estimates of elliptic type. As a further application we demonstrate how developed tools can be used to reduce singularly perturbed problems to regular ones.In dieser Dissertation betrachten wir verschiedene Aspekte der Existenz und Korrektheit asymptotischer Lösungen für elliptische Differentialgleichungen und Pseudodifferentialgleichungen. Am Anfang betrachtet die Arbeit den Fall eines allgemeinen elliptischen Grenzwertproblems in partiellen Ableitungen. Hierbei hängen die Koeffizienten von einem kleinen Parameter ab. Solche Gleichungen wurden schon reichlich untersucht, aber es gibt immer noch theoretische Lücken. Unser Ziel ist eine allgemeine Theorie elliptischer Operatorklassen mit kleinen Parametern. Zu diesem Zweck untersuchen wir im Detail den Fall eines beschränkten Gebietes mit glattem Rand. Zuerst konstruieren wir formale Lösungen als Potenzreihe einer kleinen Variablen. Weiter untersuchen wir ihre asymptotischen Eigenschaften. Dazu reicht es aus, beidseitige A-Priori Abschätzungen für diejenigen Randwertproblemoperatoren zu bestimmen, die gleichmäßig stetig von den kleinen Parametern abhängen. Solche Abschätzungen gelten nicht in Funktionenräumen, die in der klassischen elliptischen Theorie benutzt werden. Um diese Beschränkungen zu überwinden, nutzen wir Normen abhängig vom kleinen Parameter. Änliche Normen finden sich oft in der Literatur, aber ihre Eigenschaften wurden unzureichend untersucht. Unsere theoretische Forschung zeigt, dass die gewöhnliche elliptische Methode korrekt durchgeführt werden kann. Die erhaltenen Abschätzungen erlauben das Fortsetzen der Normen auf kompakte Mannigfältigkeiten mit Rand. Unsere Forschung wird mit algebraischen Bedingungen für die Operatoren abgeschlossen. Wir zeigen, dass diese Bedingungen äquivalent zu der Existenz der A-Priori-Abschätzungen sind. Im zweiten Schritt erweitern wir das Konzept der Elliptizität mit kleinen Parametern zu allgemeineren Operatorklassen. Zuerst wollen wir den Unterschied in asymptotischen Mustern zwischen der erhaltenen Reihe und Lösungen ähnlicher Probleme untersuchen. Deshalb untersuchen wir die Wärmeleitungsgleichung in einem beschränkten Gebiet mit einem kleinen Parameter in der Zeitableitung. In diesem Fall tangiert der Rand die Charakteristik endlich oft. Es ist bekannt, dass die Lösungen unregulär im Allgemeinen in Umgebungen solcher Stellen sind. Wir nehmen an, dass der Rand an solchen Stellen nicht glätt sein kann und kaspydalische Singularitäten hat. Wir haben eine formale asymptotische Zerlegung gefunden und einen Schwellenwert gezeigt, sodass die asymptotische Eigenschaft der Reihe nicht mehr gilt, wenn der Randparameter diesen Schwellenwert übersteigt. Der letze Teil der Arbeit führt ein allgemeines Konzept der Elliptizit"at mit einem kleinen Parameter ein. Mehrere theoretische Erweiterungen auf Pseudodifferentialoperatoren wurden schon in früheren Studien vorgeschlagen. Als neuen Beitrag wenden wir die Analysis auf Manigfältigkeiten mit Kantensingularitäten an. Dies lässt es zu, allgemeinere gestörte Operatorklassen zu betrachten. Wir beobachten, dass die eingef"uhrten Klassen A-Priori-Abschätzungen elliptischer Gestalt haben. Als weitere Anwendung demonstrieren wir, wie die entwickelten Mittel zum Reduzieren singular gestörter Probleme zu regulären Fällen benutzt werden können.
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Haghpanah, Nima. "Optimal Multi-parameter Auction Design." Thesis, Northwestern University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3638183.
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This thesis studies the design of Bayesian revenue-optimal auctions for a class of problems in which buyers have general (non-linear and multi-parameter) preferences. This class includes the classical linear single-parameter problem considered by Myerson (1981), for which he provided a simple characterization of revenue proving optimality of a mechanism, leading to numerous applications in theory and practice. However, for fully general preferences no generic and practical solution is known (various negative computational or structural results exist for special cases), even for the problem of designing a mechanism for a single agent. This thesis sets to identifies key conditions implying that the optimal mechanism is practical. Our main results are different in that they identify different conditions implying different notions of practicality, but are all similar in adopting a modular view to the problem that separates the task of designing a solution for the single-agent problem as the main module, from the task of combining these modules to form an optimal multi-agent mechanism. For multi-parameter linear settings, we specify a large class of distributions over values that implies that the optimal single-agent mechanism is posted pricing, and the optimal multi-agent mechanism maximizes \emph{virtual values} for players' favorite items (e.g., when agents are identical, second price auction with reserve for favorite items). More generally, we specify a condition called revenue-linearity (defined beyond multi-parameter linear settings) that implies that optimizing agents' marginal revenue maximizes revenue. Finally, adopting efficient computability as the notion of practicality, we show that for any setting in which single-agent solutions are efficiently computable, multi-agent solutions are also computable.
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Bowtell, R. W. "Spatially localised NMR parameter measurement." Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381096.
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Kaye, R. W. "Diophantine and parameter-free induction." Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383189.
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Theed, Justin Edward. "Environmental parameter for cable ratings." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287344.
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Lahlou, Tarek A. (Tarek Aziz). "Parameter recovery for transient signals." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82406.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 115-118).
Transient signals naturally arise in numerous disciplines for which the decay rates and amplitudes carry some informational significance. Even when the decay rates are known, solving for the amplitudes results in an ill-conditioned formulation. Transient signals in the presence of noise are further complicated as the signal-to-noise ratio asymptotically decreases in time. In this thesis the Discrete-Time Transient Transform and the Discrete Transient Transform are defined in order to represent a general signal using a linear combination of decaying exponential signals. A common approach to computing a change of basis is to make use of the dual basis. Two algorithms are proposed for generating a dual basis: the first algorithm is specific to a general exponential basis, e.g., real exponential or harmonically related complex exponential bases are special cases of the general exponential basis, while the second algorithm is usable for any general basis. Several properties of a transient domain representation are discussed. Algorithms for computing numerically stable approximate transient spectra are additionally proposed. The inherent infinite bandwidth of a continuous-time transient signal motivates in part the development of a framework for recovering the decay rates and amplitudes of a discrete-time lowpass filtered transient signal. This framework takes advantage of existing parameter modeling, identification, and recovery techniques to determine the decay rates while an alternating projection method utilizing the Discrete Transient Transform determines the amplitudes.
by Tarek A. Lahlou.
S.M.
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Vélez-Reyes, Miguel. "Decomposed algorithms for parameter estimation." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12845.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1992.Includes bibliographical references (leaves 215-221). Includes bibliographical references (p. 215-221).
by Miguel Vélez-Reyes.
Ph.D.
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Blitvic, Natasa. "Two-parameter noncommutative Gaussian processes." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78440.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 225-237).
The reality of billion-user networks and multi-terabyte data sets brings forth the need for accurate and computationally tractable descriptions of large random structures, such as random matrices or random graphs. The modern mathematical theory of free probability is increasingly giving rise to analysis tools specifically adapted to such large-dimensional regimes and, more generally, non-commutative probability is emerging as an area of interdisciplinary interest. This thesis develops a new non-commutative probabilistic framework that is both a natural generalization of several existing frameworks (viz. free probability, q-deformed probability) and a setting in which to describe a broader class of random matrix limits. From the practical perspective, this new setting is particularly interesting in its ability to characterize the behavior of large random objects that asymptotically retain a certain degree of commutative structure and therefore fall outside the scope of free probability. The type of commutative structure considered is modeled on the two-parameter families of generalized harmonic oscillators found in physics and the presently introduced framework may be viewed as a two-parameter deformation of classical probability. Specifically, we introduce (1) a generalized Non-commutative Central Limit Theorem giving rise to a two-parameter deformation of the classical Gaussian statistics and (2) a two-parameter continuum of non-commutative probability spaces in which to realize these statistics. The framework that emerges has a remarkably rich combinatorial structure and bears upon a number of well-known mathematical objects, such as a quantum deformation of the Airy function, that had not previously played a prominent role in a probabilistic setting. Finally, the present framework paves the way to new types of asymptotic results, by providing more general asymptotic theorems and revealing new layers of structure in previously known results, notably in the "correlated process version" of Wigner's Semicircle Law.
by Natasha Blitvić.
Ph.D.
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MacLennan, Iain James. "Two parameter engineering fracture mechanics." Thesis, University of Glasgow, 1996. http://theses.gla.ac.uk/6756/.
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The object of this work was to investigate and expand on previously carried out research into elastic-plastic crack tip fields using the first two terms of the Williams expansion to characterise the degree of crack tip constraint. As a precursor to this research a history of fracture mechanics is also presented. In the present work crack tip fields in small scale yielding have been detennined using modified boundary layer formulations in an attempt to model the influence of the second order term of the Williams expansion, the T -stress. The prime object of this thesis was to investigate and expand on previously carried out research into a two parameter characterisation of elastic-plastic crack tip fields using the second parameter of the Williams expansion(T), which attempts to characterise the degree of crack tip constraint. Modified Boundary Layer formulations in conditions of plane strain were implemented to derive a suitable reference solutions, against which the effects of out of plane strains can be compared and the validity of presently established reference fields can be gauged. The effect of out of plane non-singular stress, S, on the crack tip stress field were also considered, where constraint was largely determined by T. A wide range of analyses have been carried out, from the microstructural scale to complete engineering components in an attempt to characterise crack tip stress fields. The ability to apply two parameter fracture concepts to real engineering structures requires methods for calculating T for complex components with realistic semi-elliptical defects. A simple engineering method for achieving this was developed making use of linespring elements in the finite element package ABAQUS. This approach was validated by the calculation of T for semi-elliptical cracks at the chord-brace intersection of a tubular welded joint, modelled using the mesh generation program PATRAN. The micromechanics of cleavage, using the Ritchie-Knott-Rice model have also been constructed. This work relates the ratio of J for unconstrained and constrained geometries to critical microstructural distance, critical cleavage stress and the toughness ratio on the strainhardening effect. The elastic-plastic behaviour of short and deeply cracked bend bars has previously been described by Betegon and Hancock based on the first two terms of the Williams expansion. A local cleavage criterion has been applied to these fields to indicate the effect of loss of constraint on lower shelf toughness of shallow cracked bend bars. The work models the maximum temperature at which cleavage can occur in these geometries to show the effect of constraint and aJW ratio of cracked bend bars on the ductile-brittle transition temperature. This has also been backed by a significant experimental research program. Finally constraint dependent toughness has been considered in relation to failure assessment methodologies. A simple engineering method for modifying these Failure Assesssment Diagrams has been presented, this consists of considering the constraint matched toughness of the strucutre. This procedure recovers the original Failure Assessment Line and unifies the constraint dependent fracture toughness within defect assessment schemes which utilise Failure Assessment Diagrams.
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Jais, Mathias. "Parameter identification for Maxwell's equations." Thesis, Cardiff University, 2006. http://orca.cf.ac.uk/54581/.
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In this work we present a variational algorithm to determine the parameters iir(x) and er(x) in the Maxwell system VxE + k xTH = 0, V x H - kerE = 0 in a body Q from boundary measurements of electromagnetic pairs (n x En dci,n x Hn dn), n= 1,2,…, where n is the outer unit normal. We show that this inverse problem can be solved by minimizing a positive functional C7(m,c) and using a conjugate gradient scheme. Apart from implementations with global boundary, we also consider the case of partial boundary, where we have only data available on a subset T C dQ. Further do we develop uniqueness results, to show that the given data (n x En dn, n x Hn dn), n = 1,2,…, is a sufficient basis to solve the inverse problem. We investigate the uniqueness properties of the inverse problem in the case of global boundary data as well as in the case of partial boundary data. To show the effectivness and the stability of our approach we present various numerical results with noisy data. Finally we outline an alternative method, where one is only interested in recovering the support of the functions fi l 1 and er 1.
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Cunningham, James. "Efficient, Parameter-Free Online Clustering." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1606762403895603.
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Salomonsson, Anders. "Accuracy of material parameter estimation." Licentiate thesis, Luleå tekniska universitet, 1999. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-25758.
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This thesis deals with material parameter estimation for non-linear material models, which is an extremely important part of a finite element analysis. The aim of this work is to both estimate parameters and to quantify the their accuracy. The latter enable a total assessment of how the accuracy at different stages in i.e. the life prediction process affects the final estimated life. Thereby it is also possible to estimate the cost and value of improvements in material data in the different stages of the calculation. The thesis comprises an introductory part and two appended papers. The first paper discusses the influence on parameters and estimated life dependent on the choice of cost-function in the optimisation process. In the second a method for stress integration with regard to transverse recovery is discussed.Godkänd; 1999; 20070320 (ysko)
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Pather, Vegan. "Parameter learning with particle filters." Master's thesis, Faculty of Commerce, 2021. http://hdl.handle.net/11427/32913.
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Common applications of asset-pricing models in practice rely on recalibrating model parameters periodically for effective risk management. Yet, these model parameters are often assumed to be constant over time, thereby countering the notion of readjusting these values. A possible solution to this problem is to recalibrate at times where observed market prices cannot realistically match model prices based on parameter values at those times. This dissertation aims to test the effectiveness of a possible algorithm which can be used in optimally identifying such times. An overview is provided of the recently proposed particle filter with accelerated adaptation which has demonstrated rapid time detection for changes in parameter values and has been applied to regime-shifting and stochastic volatility models. Numerical and graphical evidence of parameter and volatility estimation will be provided under regime-shifting parameters for the Heston (1993) stochastic volatility model. The filter demonstrates rapid adaptation in estimating parameter values and accurate estimation of the volatility process. Furthermore, we provide a discussion for possible extensions towards a metric for optimal recalibration times.
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Sun, Shuo. "Parameter Estimation of Microwave Filters." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc822826/.
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The focus of this thesis is on developing theories and techniques to extract lossy microwave filter parameters from data. In the literature, the Cauchy methods have been used to extract filters’ characteristic polynomials from measured scattering parameters. These methods are described and some examples are constructed to test their performance. The results suggest that the Cauchy method does not work well when the Q factors representing the loss of filters are not even. Based on some prototype filters and the relationship between Q factors and the loss, we conduct preliminary studies on alternative representations of the characteristic polynomials. The parameters in these new models are extracted using the Levenberg–Marquardt algorithm to accurately estimate characteristic polynomials and the loss information.
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Norris, Mark A. "Parameter identification in distributed structures." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/71164.
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This dissertation develops two new techniques for the identification of parameters in distributed-parameter systems. The first technique identifies the physical parameter distributions such as mass, damping and stiffness. The second technique identifies the modal quantities of self-adjoint distributed-parameter systems.
Distributed structures are distributed-parameter systems characterized by mass, damping and stiffness distributions. To identify the distributions, a new identification technique is introduced based on the finite element method. With this approach, the object is to identify "average" values of mass, damping and stiffness distributions over each finite element. This implies that the distributed parameters are identified only approximately, in the same way in which the finite element method approximates the behavior of a structure.
It is common practice to represent the motion of a distributed parameter system by a linear combination of the associated modes of vibration. In theory, we have an infinite set of modes although, in practice we are concerned with only a finite linear combination of the modes. The modes of vibration possess certain properties which distinguish them from one another. Indeed, the modes of vibration are uncorrelated in time and orthogonal in space. The modal identification technique introduced in this dissertation uses path these spatial properties. Because both the temporal and spatial properties are used, the method does not encounter problems when the natural frequencies are closely-spaced or repeated.Ph. D.
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Badayos, Noah Garcia. "Machine Learning-Based Parameter Validation." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/47675.
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As power system grids continue to grow in order to support an increasing energy demand, the system's behavior accordingly evolves, continuing to challenge designs for maintaining security. It has become apparent in the past few years that, as much as discovering vulnerabilities in the power network, accurate simulations are very critical. This study explores a classification method for validating simulation models, using disturbance measurements from phasor measurement units (PMU). The technique used employs the Random Forest learning algorithm to find a correlation between specific model parameter changes, and the variations in the dynamic response. Also, the measurements used for building and evaluating the classifiers were characterized using Prony decomposition. The generator model, consisting of an exciter, governor, and its standard parameters have been validated using short circuit faults. Single-error classifiers were first tested, where the accuracies of the classifiers built using positive, negative, and zero sequence measurements were compared. The negative sequence measurements have consistently produced the best classifiers, with majority of the parameter classes attaining F-measure accuracies greater than 90%. A multiple-parameter error technique for validation has also been developed and tested on standard generator parameters. Only a few target parameter classes had good accuracies in the presence of multiple parameter errors, but the results were enough to permit a sequential process of validation, where elimination of a highly detectable error can improve the accuracy of suspect errors dependent on the former's removal, and continuing the procedure until all corrections are covered.Ph. D.
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Koripalli, RadhaShilpa. "Parameter Tuning for Optimization Software." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/2862.
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Mixed integer programming (MIP) problems are highly parameterized, and finding parameter settings that achieve high performance for specific types of MIP instances is challenging. This paper presents a method to find the information about how CPLEX solver parameter settings perform for the different classes of mixed integer linear programs by using designed experiments and statistical models. Fitting a model through design of experiments helps in finding the optimal region across all combinations of parameter settings. The study involves recognizing the best parameter settings that results in the best performance for a specific class of instances. Choosing good setting has a large effect in minimizing the solution time and optimality gap.
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Sui, Liqi. "Uncertainty management in parameter identification." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2330/document.
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Afin d'obtenir des simulations plus prédictives et plus précises du comportement mécanique des structures, des modèles matériau de plus en plus complexes ont été développés. Aujourd'hui, la caractérisation des propriétés des matériaux est donc un objectif prioritaire. Elle exige des méthodes et des tests d'identification dédiés dans des conditions les plus proches possible des cas de service. Cette thèse vise à développer une méthodologie d'identification efficace pour trouver les paramètres des propriétés matériau, en tenant compte de toutes les informations disponibles. L'information utilisée pour l'identification est à la fois théorique, expérimentale et empirique : l'information théorique est liée aux modèles mécaniques dont l'incertitude est épistémique; l'information expérimentale provient ici de la mesure de champs cinématiques obtenues pendant l'essai ct dont l'incertitude est aléatoire; l'information empirique est liée à l'information à priori associée à une incertitude épistémique ainsi. La difficulté principale est que l'information disponible n'est pas toujours fiable et que les incertitudes correspondantes sont hétérogènes. Cette difficulté est surmontée par l'utilisation de la théorie des fonctions de croyance. En offrant un cadre général pour représenter et quantifier les incertitudes hétérogènes, la performance de l'identification est améliorée. Une stratégie basée sur la théorie des fonctions de croyance est proposée pour identifier les propriétés élastiques macro et micro des matériaux multi-structures. Dans cette stratégie, les incertitudes liées aux modèles et aux mesures sont analysées et quantifiées. Cette stratégie est ensuite étendue pour prendre en compte l'information à priori et quantifier l'incertitude associéeIn order to obtain more predictive and accurate simulations of mechanical behaviour in the practical environment, more and more complex material models have been developed. Nowadays, the characterization of material properties remains a top-priority objective. It requires dedicated identification methods and tests in conditions as close as possible to the real ones. This thesis aims at developing an effective identification methodology to find the material property parameters, taking advantages of all available information. The information used for the identification is theoretical, experimental, and empirical: the theoretical information is linked to the mechanical models whose uncertainty is epistemic; the experimental information consists in the full-field measurement whose uncertainty is aleatory; the empirical information is related to the prior information with epistemic uncertainty as well. The main difficulty is that the available information is not always reliable and its corresponding uncertainty is heterogeneous. This difficulty is overcome by the introduction of the theory of belief functions. By offering a general framework to represent and quantify the heterogeneous uncertainties, the performance of the identification is improved. The strategy based on the belief function is proposed to identify macro and micro elastic properties of multi-structure materials. In this strategy, model and measurement uncertainties arc analysed and quantified. This strategy is subsequently developed to take prior information into consideration and quantify its corresponding uncertainty
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Cho, Sung Don. "Parameter estimation for transformer modeling /." Available online. Click here, 2002. http://sunshine.lib.mtu.edu/ETD/DISS/chosd/SungCho.pdf.
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