Dissertations / Theses on the topic 'Free methods'
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Pekmen, Bengisen. "Derivative Free Multilevel Optimization Methods." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610853/index.pdf.
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Derivative free optimization algorithms are implementations of trust region based derivative-free methods using multivariate polynomial interpolation. These are designed to minimize smooth functions whose derivatives are not available or costly to compute. The trust region based multilevel optimization algorithms for solving large scale unconstrained optimization problems resulting by discretization of partial differential equations (PDEs), make use of different discretization levels to reduce the computational cost. In this thesis, a derivative free multilevel optimization algorithm is derived and its convergence behavior is analyzed. The effectiveness of the algorithms is demonstrated on a shape optimization problem.
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Mason, C. J. "Numerical methods for free boundary problems." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37775.
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Kubczyk, Tomasz Miroslaw. "Metal-free C-H functionalisation methods." Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27485.
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Rees, M. D. "Moving point, particle and free-Lagrange methods." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235079.
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Schopf, Patrick. "Development and application of free energy methods." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/366938/.
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The development of free energy simulation protocols for calculating relative binding free energies of ligands is presented in this thesis. To this end, the protein Dihydroorotate Dehydrogenase (DHODH), complexed to a highly congeneric series of compounds that show ambiguities in their binding modes, was studied in detail. To estimate the systematic error in force fields, relative free energies of hydration have been calculated using Replica-exchange Thermodynamic Integration (RETI) for sets of force field parameters and atomic partial charges in a classical molecular mechanics environment as well as a novel hybrid molecular mechanics/quantum mechanics model. The results demonstrated that all force fields and methods employed yield similar estimates of the relative free energies, while GAFF and OPLS-AA in conjunction with AM1BCC and AM1CM1A charges, respectively, performed best. To balance accuracy and ease of generating parameters, GAFF in conjunction with AM1BCC charges was selected to be the most valuable for describing the inhibitors in DHODH. To rigorously assess the thermodynamic end states for the ligands, crystal hydrates present in the binding site of DHODH have been investigated using the Just-Add-Water-molecules (JAWS) algorithm, Grand-canonical Monte Carlo (GCMC) simulations and the double-decoupling approach (DDM). These findings clearly suggested a change in hydration networks for both the inhibitors and their different binding modes, while all three approaches essentially yield identical results. This allowed us to construct free energy cycles using the single and dual topology approach in order to calculate the free energies of binding of the ligands as well as the stability of their binding modes. The results obtained were precise within the error of the methods, but not accurate, and allowed to complement the crystallographic findings.
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Yakutovich, Mikhail. "Mesh-free methods for liquid crystal simulation." Thesis, Sheffield Hallam University, 2009. http://shura.shu.ac.uk/20580/.
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The key aim of this Thesis is the development and implementation of a set of simulation techniques for LCs capable of tackling mesoscopic phenomena. In this, we concentrate only on mesh-free particle numerical techniques. Two broad approaches are used, namely bottom-up and top-down. While adopting the bottom-up approach, we employ the DPD method as a foundation for devising a novel LC simulation technique. In this, we associate a traceless symmetric order tensor, Q, with each DPD particle. We then further extend the DPD forces to directly incorporate the Q tensor description so as to recover a more complete representation of LC behaviour. The devised model is verified against a number of qualitative examples and applied to the simulation of colloidal particles immersed in a nematic LC. We also discuss advantages of the developed model for simulation of dynamic mesoscopic LC phenomena. In the top-down approach, we utilise recently emergent numerical mesh-free methods. Specifically, we use the SPH method and its variants. The developed method includes hydrodynamics, variable order parameter and external electric and magnetic fields. The developed technique is validated against a number of analytical and numerical solutions. Subsequently, we apply our top-down methods to the simulation of the complex 3D post-aligned bistable nematic (PABN) device. This includes a smooth geometry representation in order to fully exploit the developed mesh-free numerical techniques. We study both the static and dynamic behaviours of the PABN device for a number of distinct post shapes.
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Silverberg, Jon P. "On Lagrangian meshless methods in free-surface flows." Thesis, (1.7 MB), 2005. http://edocs.nps.edu/AR/topic/theses/2005/Jan/05Jan_Silverberg.pdf.
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Thesis (Master of Engineering in Ocean Engineering)--University of California at Berkeley, 2004."January 2005." Description based on title screen as viewed on May 25, 2010. DTIC Descriptor(s): Fluid Dynamics, Lagrangian Functions, Equations Of Motion, Acceleration, Formulations, Grids, Continuum Mechanics, Gaussian Quadrature, Derivatives (Mathematics), Compact Disks, Boundary Value Problems, Polynomials, Interpolation, Pressure, Operators (Mathematics). DTIC Identifier(s): Multimedia (CD-Rom), Moving Grids, Meshless Discretization, Lifs (Lagrange Implicit Fraction Step), Lagrangian Dynamics, Meshless Operators, Mlip (Multidimensional Lagrange Interpolating Polynomials), Flux Boundary Conditions, Radial Basis Functions Includes bibliographical references (58-59).
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Brummelen, Einar Harald van. "Numerical methods for steady viscous free-surface flows." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2002. http://dare.uva.nl/document/64507.
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Shaw, Katherine E. "Testing QM/MM Methods Using Free Energy Simulations." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525442.
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Schraeder, Daniela. "Analytically divergence-free discretization methods for Darcy's problem." Thesis, University of Sussex, 2010. http://sro.sussex.ac.uk/id/eprint/2327/.
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Radial basis functions are well known for their applications in scattered data approximation and interpolation. They can also be applied in collocation methods to solve partial differential equations. We develop and analyse a mesh-free discretization method for Darcy's problem. Our approximation scheme is based upon optimal recovery, which leads to a collocation scheme using divergence-free positive denite kernels. Besides producing analytically incompressible flow fields, our method can be of arbitrary order, works in arbitrary space dimension and for arbitrary geometries. Firstly we establish Darcy's problem. To introduce the scheme we review and study divergence-free and curl-free matrix-valued kernels and their reproducing kernel Hilbert spaces. After developing the scheme, we find the approximation error for smooth target functions and the optimal approximation orders. Furthermore, we develop Sobolev-type error estimates for target functions rougher than the approximating function and show that the approximation properties extend to those functions. To find these error estimates, we apply band-limited approximation. Finally, we illustrate the method with numerical examples.
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Bridgwater, Sally. "Accurate free energy methods for model organic solids." Thesis, University of Warwick, 2014. http://wrap.warwick.ac.uk/66466/.
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We discuss existing free energy methods for use with investigation of solid-solid polymorphism. An alternative implementation for phase switch Monte Carlo is introduced which samples from two synchronised Markov chains exploring both polymorphs, using a set of generalised coordinates to transform between Markov chains. This is validated against the existing results for face-centred cubic (fcc) and hexagonal close-packed (hcp) hard sphere crystals. The extension to more complex crystals including flexibility and constraints is explored. This extension is applied to a hard sphere model of linear alkanes. A phase transition in density is accurately located between two polymorphs of n-butane with increasing density; this is suggested as a rigorous benchmark for free energy methods. We also demonstrate the importance of including anisotropic volume moves when simulating crystalline solids. Generalised coordinates for any fully flexible molecular system of soft particles are presented. These are used to investigate a coarse-grain model of cholesterol in regards to the polymorphic transition between two anhydrous cholesterol crystals. A phase transition in temperature is found and the limitations in the model are discussed.
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Gao, Huina. "Analysis of distribution-free methods for revenue management." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8783.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2008.Thesis research directed by: Robert H. Smith School of Business. Dept. of Decision and Information Technologies. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Facchinetti, Alessandro <1991>. "Likelihood free methods for inference on complex models." Master's Degree Thesis, Università Ca' Foscari Venezia, 2020. http://hdl.handle.net/10579/17017.
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Complex models often have intractable likelihoods, so methods that involve evaluation of the likelihood function are infeasible. The aims of the research are
• to provide a review of the likelihood free methods (e.g., ABC or synthetic likelihood) used in fitting complex models large dataset;
• to use likelihood free methods to make inference on complex models such as random networks models;
• to develop the code for the analysis;
• to apply the model and methods for networks data from economics and finance such as trade, financial flows networks, financial contagion networks;
• to write a final report where methods and results are presented and discussed.
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Fernàndez, Méndez Sònia. ""Mesh-free methods and finite elements: friend or foe?"." Doctoral thesis, Universitat Politècnica de Catalunya, 2001. http://hdl.handle.net/10803/6705.
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This thesis is devoted to the numerical analysis of mesh-free methods and, in particular, to the study of the possible advantages of the EFG (Element Free Galerkin) mesh-free method against the well-known FE (Finite Element) method. More precisely, the EFG method and the FE method behavior are compared in two particular interesting problems: (1) analysis of volumetric locking in mechanical problems and (2) accurate resolution of transient convection dominated problems. In both cases the good properties and possibilities of mesh-free methods become apparent. However, in several situations the FE method is still more competitive: for instance, the computation of the FE shape functions and its integrals are less costly, and essential boundary conditions can be easily imposed. Thus, in order to take advantage of the good properties of both methods, a mixed interpolation combining FE and EFG is proposed. This formulation can be applied in two useful situations: (i) enrichment of finite elements with EFG, and (ii) coupling of FE and EFG. An a priori error estimate for the first one is presented and proved. Several examples show the applicability of the mixed interpolation in adaptive computations.
Aquesta tesi està dedicada a l'anàlisi numèrica dels mètodes sense malla i, en particular, a l'estudi dels possibles avantatges del mètode EFG (Element Free Galerkin) davant del ben conegut MEF (Mètode dels Elements Finits). Concretament, es comparen el mètode EFG i el MEF en dos problemes concrets d'interès: (1) l'anàlisi del bloqueig volumètric en problemes mecànics i (2) la resolució precisa de problemes transitoris amb convecció dominant. Les bones propietats i possibilitats dels mètodes sense malla es fan evidents en tots dos casos.
Tot i així, en varis aspectes el MEF resulta més competitiu: per exemple, el càlcul de les funcions de forma i de les seves integrals es menys costós, i les condicions de contorn essencials es poden imposar fàcilment. Amb l'objectiu d'aprofitar les bones qualitats dels dos mètodes, es proposa una interpolació mixta combinant elements finits y EFG, aplicable en dues situacions: (i) enriquiment d'elements finits amb EFG i (ii) acoblament d'elements finits i EFG. Per al primer cas, es presenta i demostra una cota a priori de l'error. L'aplicabilitat d'aquesta interpolació mixta en processos adaptatius es mostra amb varis exemples.
Esta tesis está dedicada al análisis numérico de los métodos sin malla y, en particular, al estudio de las posibles ventajas del método EFG (Element Free Galerkin) frente al bien conocido MEF (Método de los Elementos Finitos). Concretamente, se comparan el método EFG y el MEF en dos problemas concretos de interés: (1) el análisis del bloqueo volumétrico en problemas mecánicos y (2) la resolución precisa de problemas transitorios con convección dominante. Las buenas propiedades y posibilidades de los métodos sin malla se hacen evidentes en ambos casos.
Sin embargo, en varios aspectos el MEF resulta más competitivo: por ejemplo, el cálculo de las funciones de forma y sus integrales es menos costoso, y las condiciones de contorno esenciales se pueden imponer fácilmente. Con el objetivo de aprovechar las buenas cualidades de ambos métodos, se propone una interpolación mixta combinando elementos finitos y EFG, aplicable en dos situaciones: (i) enriquecimiento de elementos finitos con EFG, y (ii) acoplamiento de elementos finitos y EFG. Para el primer caso, se presenta y demuestra una cota a priori del error. La aplicabilidad de esta interpolación mixta en procesos adaptativos se muestra con varios ejemplos.
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Sidahmed, Abdelmgid Osman Mohammed. "Mesh free methods for differential models in financial mathematics." Thesis, University of the Western Cape, 2011. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_3917_1319185202.
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Many problems in financial world are being modeled by means of differential equation. These problems are time dependent, highly nonlinear, stochastic and heavily depend on the previous history of time. A variety of financial products exists in the market, such as forwards, futures, swaps and options. Our main focus in this thesis is to use the numerical analysis tools to solve some option pricing problems. Depending upon the inter-relationship of the financial derivatives, the dimension of the associated problem increases drastically and hence conventional methods (for example, the finite difference methods or finite element methods) for solving them do not provide satisfactory results. To resolve this issue, we use a special class of numerical methods, namely, the mesh free methods. These methods are often better suited to cope with changes in the geometry of the domain of interest than classical discretization techniques. In this thesis, we apply these methods to solve problems that price standard and non-standard options. We then extend the proposed approach to solve Heston' volatility model. The methods in each of these cases are analyzed for stability and thorough comparative numerical results are provided.
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Arnarson, Teitur. "PDE methods for free boundary problems in financial mathematics." Doctoral thesis, KTH, Matematik (Inst.), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4777.
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We consider different aspects of free boundary problems that have financial applications. Papers I–III deal with American option pricing, in which case the boundary is called the early exercise boundary and separates the region where to hold the option from the region where to exercise it. In Papers I–II we obtain boundary regularity results by local analysis of the PDEs involved and in Paper III we perform local analysis of the corresponding stochastic representation. The last paper is different in its character as we are dealing with an optimal switching problem, where a switching of state occurs when the underlying process crosses a free boundary. Here we obtain existence and regularity results of the viscosity solutions to the involved system of variational inequalities.QC 20100630
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Birkevold, Jens. "Divergence-free Isogeometric Methods for Flow in Porous Media." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for matematiske fag, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19546.
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This thesis is focused on solving the Darcy flow problem using divergence-free isogeometric methods, and comparing these results to the ones obtained using traditional finite element methods with Taylor Hood elements. A short introduction to B-splines is given, and a chapter is also about using repeated knots in the knot vectors to obtain a discontinuous basis for the finite element method. This can be useful when dealing with varying permeabilities.
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Söderström, Andreas. "Memory Efficient Methods for Eulerian Free Surface Fluid Animation." Doctoral thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-60852.
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This thesis focuses on improving and extending the available toolset for Eulerian, i.e. grid based, free surface fluid animation and level set based surface tracking in the context of computer graphics and visual effects. More specifically three novel methods are presented each aimed towards reducing the amount of computer memory required for producing high resolution animations of incompressible free surface fluids. Each method is primarily developed for, but not limited to, the popular Stable Fluids method. Eulerian free surface fluid animation has historically required a large amount of computer memory, especially when high resolution results are desired. This problem has recently been addressed through the development of dynamic computational grids like the Dynamic Tubular Grid (DT-Grid) for level set computations. However, when animating free surface fluids a large amount of tracker particles are often added to the level set geometry in order to provide more accurate tracking of fluid surfaces. As a result the particle level set (PLS) method typically requires two orders of magnitude more memory than a DT-Grid level set. In order to reduce the gap in memory requirement between the level set and the particles this thesis introduces a fast and efficient compression method for such tracker particles. This compression is optionally combined with a specialized external memory algorithm that allows particle and level set data to be efficiently streamed back and forth between primary memory and secondary storage devices such as hard disk drives. The particle compression scheme is able to reduce the size of a DT-Grid particle level set by more than 65% while only inducing a 5% penalty to performance. If combined with the external memory algorithm particle level sets of virtually any size and resolution can be used in free surface fluid animations. The induced performance penalty of the combined scheme depends on the performance of the external storage device, however when using a traditional hard disk drive a 70% increase in simulation time was measured. This thesis also presents a purely Eulerian alternative to the PLS method through the introduction of a dual resolution level set representation. The method replaces the tracker particles with a level set of higher resolution, thus significantly increasing surface tracking accuracy compared to the unaided level set. The scheme is able to produce high quality results using up to 94% less memory than a PLS. The core component of the method is the Spatially Adaptive Morphology (SAM) filter which connects the high resolution representation of the level set with the lower resolution fluid, thus providing plausable animation also for small and/or thin surface features. A sheet preserving extension to the SAM filter is also presented that is able to preserve thin sheets of fluid indefinitely if so desired. Although this method adds mass to the simulation it is highly useful for animating phenomena like splashes, fountains and waterfalls. The final method presented in this thesis concerns the efficient local animation of oceans and other very large free surface fluids.For such scenarios large amounts of memory and computation time can be saved by only computing accurate fluid physics in a local fluid region immediately surrounding a point of interest. The fluid outside this region can then be animated using less accurate but significantly faster and less memory demanding models. However, for this approach to be accurate the local fluid must be contained in such a way that it behaves as if still part of a larger fluid. This thesis enables the local simulation of a larger body of fluid by introducing three different non-reflective boundary conditions for free surface fluid animation using a modified Stable Fluids method. Two simple wave dampening boundaries are presented as well as a significantly more advanced wave absorbing boundary based on the Perfectly Matched Layer (PML) approach. All three boundaries are shown to be effective in preventing wave reflection given large enough boundary regions. However the PML boundary is significantly more efficient, typically absorbing waves at a fraction of the distance required by the other two methods.
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Bergström, Per. "Computational methods for shape verification of free-form surfaces." Doctoral thesis, Luleå tekniska universitet, Matematiska vetenskaper, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17878.
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Beräkningsmetoder för formverifiering av friformsytor utgör huvudinnehållet i denna doktorsavhandling. En gemensam egenskap för dessa metoder är att de möjliggör formverifiering online direkt i produktionslinan. Av den anledningen måste metoderna vara snabba och robusta. Ett av problemen som uppkommer i formverifieringen av friformsytor är registrering. Det är problemet med att matcha datapunkter i 3D-rymden, som representerar den uppmätta ytan, med ett CAD-objekt genom att ansätta en stelkropps transformation. En metod för att utföra registreringen snabbt och robust är utvecklad. Metoden är en utveckling av ”the iterative closest point method, ICP”. Vi förprocessar CAD-objektet genom att skapa en datastruktur för att möjliggöra snabb närmsta-punkt sökning. Initialt läggs mycket tid på att skapa datastrukturen för att de enskilda registreringarna skall gå snabbt. Den robusta registreringen baserar sig på teorier från robust statistik genom att tillämpa ”iteratively re-weighted least squares” i kombination med ICP metoden. Detta resulterar i en snabb registreringsmetod som är okänslig för avvikande data. Metoden med registreringen används i en tillämpning för att hitta avvikelser mellan formen för ett objekt och dess ideala form. Den ideala formen är känd och ges av ett CAD-objekt. En optisk formmätningsmetod, projicerade fransar med en enda mönsterdetektering, används för att skapa datapunkter av den uppmätta ytan. Denna metod är snabb och okänslig för vibrationer men datapunkterna kan innehålla fel i vissa regioner, vilket hanteras av registreringen. Ett inversproblem som uppkommer i många optiska formmätningsmetoder är fasuppvikning. Vi introducerar en uppvikningsmetod med regularisering genom att använda information från ett CAD-objekt. Formmätningsmetoden som vi använder oss av här baserar sig på två-våglängds holografi. Vår fasuppvikningsmetod funkar oberoende av diskoninuiteter men mätobjektet får inte avvika alltför mycket i form jämfört med CAD-objektet. En metod för att snabbt få fram den behövda forminformationen från CAD-objektet är också utvecklad. För att få fram lämplig forminformation från datapunkter kan en parametrisk kurva eller yta, t.ex. NURBS, anpassas till dessa punkter. Ett delproblem som uppstår vid NURBS-anpassning vid användandet av Gauss-Newton metoden är studerad. Beräkningsaspekter för att få fram en sökriktning är diskuterade. Vi behandlar också metoder för NURBS anpassning som baserar sig på en teknik för separabla icke-linjära minstakvadratproblem. Denna teknik använder sig av variabelprojektioner för att separera beräkningarna av de linjära parametrarna från beräkningarna av de icke-linjära parametrarna.Godkänd; 2011; Bibliografisk uppgift: Sammanläggningsavhandling bestående av sju artiklar och en tillhörande kappa.; 20110509 (berper); DISPUTATION Ämnesområde: Teknisk-vetenskapliga beräkningar/Scientific Computing Opponent: Professor Mårten Gulliksson, Institutionen för naturvetenskap, teknik och matematik, Mittuniversitetet, Sundsvall Ordförande: Docent Inge Söderkvist, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet, Luleå Tid: Tisdag den 27 september 2011, kl 10.30 Plats: D2214-15, Luleå tekniska universitet
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Brown, David. "The synthesis of amino acids by free radical methods." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670245.
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Alkhateeb, Osama. "Singularity-Free Boundary Methods for Electrostatics and Wave Scattering." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1334816052.
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Cummings, Rebecca. "Development and application of label free quantitative proteomic methods." Thesis, University of Liverpool, 2012. http://livrepository.liverpool.ac.uk/8313/.
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The aim of this Ph.D. was to develop advanced methods for quantitative proteomics and use these methods to investigate the presence of protein biomarkers of sperm performance, differential expression of sperm membrane proteins and differential expression of E.coli proteins. Quantitative analysis of E.coli generated analytical samples that were analysed with multiple mass spectrometers and with multiple software packages. Through these samples an optimal label free quantitative proteomic workflow was generated and software was thoroughly tested to determine the optimal software to be used for data analysis on varying biological questions. Identification of protein(s) that correlate with increased or decreased fertility would be economically beneficial. Currently semen samples are subject to quality control where general movement and morphological defects are studied, but this does not always correlate with the ejaculate passing a post cryopreservation quality control check or that specific bull generating offspring. Identification of a protein or set of proteins with abundance variation in bulls of known high or low fertility would allow lower fertility bulls to be removed from the breeding programme at an early age, reducing rearing costs, and would allow longitudinal health monitoring of individual bulls. Discovery of differentially expressed proteins in the membrane of sperm with the X or Y chromosome would allow the generation of a method to separate the two sperm populations. This will be beneficial as most livestock farmers would prefer offspring of a specific sex, either to sell or replenish animal stock. Quantitative analysis of proteins present in bovine seminal plasma led to the identification and quantitative comparison of the seminal plasma proteins present in two breeds of bull, Holstein and Belgian Blue and a quantitative comparison of the seminal plasma from two domestic farm animal species, bovine and porcine. Intra species comparisons determined no quantitative variation between the two breeds, while the inter species comparison determined variation between the proteins present in both species seminal plasma and the corresponding amounts of proteins present in both species. A quantitative comparison was performed to determine the expression of proteins from two strains of E.coli, a wild type strain (MG1655) and a genome depleted strain (MDS66), this led to the confirmation of gene deletions in the genome depleted strain due to their lack of protein products in mass spectrometric analysis, and the identification of proteins that were differentially expressed due to pleiotropic effects of these genome deletions. To investigate the proteins expressed in the sperm membrane a mass spectrometer compatible enrichment method was generated and membrane proteins were identified, quantified and compared between sperm expressing X and Y chromosomes. This study did not lead to the determination of any proteins with differential expression in the X or Y bearing sperm.
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Zhang, Yubo. "Moving mesh methods for viscoelastic flows with free boundaries." HKBU Institutional Repository, 2009. http://repository.hkbu.edu.hk/etd_ra/1072.
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Amon, Lynn. "Methods for calculating the free energy of atomic clusters /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/8595.
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Neuerman, Robert A. "Simulation and design methods for free-electron laser systems." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Dec/09Dec%5FNeuerman.pdf.
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Thesis (M.S. in Applied Physics)--Naval Postgraduate School, December 2009.Thesis Advisor(s): Colson, William B. ; Blau, Joseph. "December 2009." Description based on title screen as viewed on January 28, 2010. Author(s) subject terms: Free-electron lasers, FEL simulations, undulators, FEL oscillators, FEL amplifiers, diamond field-emitter arrays, field emission cathodes, cathode test cell. Includes bibliographical references (p. 45). Also available in print.
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Olsson, Per-Magnus. "Methods for Network Optimization and Parallel Derivative-free Optimization." Doctoral thesis, Linköpings universitet, Optimeringslära, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-104110.
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This thesis is divided into two parts that each is concerned with a specific problem. The problem under consideration in the first part is to find suitable graph representations, abstractions, cost measures and algorithms for calculating placements of unmanned aerial vehicles (UAVs) such that they can keep one or several static targets under constant surveillance. Each target is kept under surveillance by a surveillance UAV, which transmits information, typically real time video, to a relay UAV. The role of the relay UAV is to retransmit the information to another relay UAV, which retransmits it again to yet another UAV. This chain of retransmission continues until the information eventually reaches an operator at a base station. When there is a single target, then all Pareto-optimal solutions, i.e. all relevant compromises between quality and the number of UAVs required, can be found using an efficient new algorithm. If there are several targets, the problem becomes a variant of the Steiner tree problem and to solve this problem we adapt an existing algorithm to find an initial tree. Once it is found, we can further improve it using a new algorithm presentedin this thesis. The second problem is optimization of time-consuming problems where the objective function is seen as a black box, where the input parameters are sent and a function valueis returned. This has the important implication that no gradient or Hessian information is available. Such problems are common when simulators are used to perform advanced calculations such as crash test simulations of cars, dynamic multibody simulations etc. It is common that a single function evaluation takes several hours. Algorithms for solving such problems can be broadly divided into direct search algorithms and model building algorithms. The first kind evaluates the objective function directly, whereas the second kind builds a model of the objective function, which is then optimized in order to find a new point where it is believed that objective function has agood value. Then the objective function is evaluated in that point. Since the objective function is very time-consuming, it is common to focus on minimizing the number of function evaluations. However, this completely disregards the possibility to perform calculations in parallel and to exploit this we investigate different ways parallelization can be used in model-building algorithms. Some of the ways to do this is to use several starting points, generate several new points in each iteration, new ways of predicting a point’s value and more. We have implemented the parallel extensions in one of the state of the art algorithms for derivative-free optimization and report results from testing on synthetic benchmarksas well as from solving real industrial problems.
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Joussef, Antonio Carlos. "Free radical methods for synthesis of biologically important compounds." reponame:Repositório Institucional da UFSC, 1990. https://repositorio.ufsc.br/handle/123456789/111799.
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Akyazi, Fatma Dilay. "Element-free Galerkin Method For Plane Stress Problems." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611685/index.pdf.
Full textAbstract:
In this study, the Element-Free Galerkin (EFG) method has been used for the analysis of plane stress problems. A computer program has been developed by using FORTRAN language. The moving least squares (MLS) approximation has been used in generating shape functions. The results obtained by the EFG method have been compared with analytical solution and the numerical results obtained by MSC. Patran/Nastran. The comparisons show that the mesh free method gives more accurate results than the finite element approximation with less computational effort.
29
Minter, Sam. "Speech on College Campuses: Methods, Motives, and Movements." Scholarship @ Claremont, 2017. http://scholarship.claremont.edu/cmc_theses/1698.
Full textAbstract:
Are campus movements concerning free speech—from Berkeley in the 1960s to the campaign against political correctness today—really about speech? Are movements really concerned with civil liberties on campus or are their calls for free speech excited by partisan motives? While free speech movements are never purely driven by civil libertarian concerns, they should not be considered simply partisan either. Campus speech movements have frequently united activists across the ideological spectrum, which suggests that these movements aren’t only sectarian in nature. It also confirms that these movements are in fact about speech, because those advocating for it have a wide range of motives, but free speech is the point of agreement. However, this is not to say that there aren’t ulterior partisan underpinnings in these pushes for free speech.
30
Hursit, Adem E. "Applications of conformal methods to relativistic trace-free matter models." Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/36674.
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Conformal methods have proven to be very useful in the analysis global properties and stability of vacuum spacetimes in general relativity. These methods transform the physical spacetime into a different Lorentzian manifold known as the unphysical spacetime where the ideal points at infinity are located at a finite position. This thesis makes use of conformal methods and applies them to various problems involving trace-free matter models. In particular, it makes progress towards the understanding of the evolution of unphysical spacetimes perturbed by trace-free matter as well as the behaviour of the the matter itself. To this end, evolution equations (wave equations) are derived and analyzed for both the unphysical spacetime and the matter. To investigate the relation between solutions of these wave equations to the Einstein field equations, a suitable system of subsidiary evolution equations is also derived. Furthermore, this thesis looks in detail at the behaviour of an unphysical spacetime coupled to the simplest matter trace free model: the confomally invariant scalar field. Finally, the system of conformal wave equations is used to show that the deSitter spacetime is non-linearly stable under perturbations by trace-free matter.
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Zhang, Zan. "Numerial development of an improved element-free Galerkin method for engineering analysis /." access full-text access abstract and table of contents, 2009. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-bc-b23750613f.pdf.
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Thesis (Ph.D.)--City University of Hong Kong, 2009."Submitted to the Department of Building and Construction in partial fulfillment of the requirements for the degree of Doctor of Philosophy." Includes bibliographical references (leaves [170]-184)
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Lee, Haegyun. "Level-set finite element simulation of free-surface flow." Diss., University of Iowa, 2007. http://ir.uiowa.edu/etd/168.
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Vidal, Seguí Yolanda. "Mesh-Free Methods for Dynamic Problems. Incompressibility and Large Strain." Doctoral thesis, Universitat Politècnica de Catalunya, 2005. http://hdl.handle.net/10803/6709.
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This thesis makes two noteworthy contributions in the are of mesh-free methods: a Pseudo-Divergence-Free (PDF) Element Free Galerkin (EFG) method which alleviates the volumetric locking and a Stabilized Updated Lagrangian formulation which allows to solve fast-transient dynamic problems involving large distortions. The thesis is organized in the following way. First of all, this thesis dedicates one chapter to the state of the art of mesh-free methods. The main reason is because there are many mesh-free methods that can be found in the literature which can be based on different ideas and with different properties. There is a real need of classifying, ordering and comparing these methods: in fact, the same or almost the same method can be found with different names in the literature.
Secondly, a novel improved formulation of the (EFG) method is proposed in order to alleviate volumetric locking. It is based on a pseudo-divergence-free interpolation. Using the concept of diffuse derivatives an a convergence theorem of these derivatives to the ones of the exact solution, the new approximation proposed is obtained imposing a zero diffuse divergence. In this way is guaranteed that the method verifies asymptotically the incompressibility condition and in addition the imposition can be done a priori. This means that the main difference between standard EFG and the improved method is how is chosen the interpolation basis. Modal analysis and numerical results for two classical benchmark tests in solids corroborate that, as expected, diffuse derivatives converge to the derivatives of the exact solution when the discretization is refined (for a fixed dilation parameter) and, of course, that diffuse divergence converges to the exact divergence with the expected theoretical rate. For standard EFG the typical convergence rate is degrade as the incompressible limit is approached but with the improved method good results are obtained even for a nearly incompressible case and a moderately fine discretization. The improved method has also been used to solve the Stokes equations. In this case the LBB condition is not explicitly satisfied because the pseudo-divergence-free approximation is employed. Reasonable results are obtained in spite of the equal order interpolation for velocity and pressure.
Finally, several techniques have been developed in the past to solve the well known tensile instability in the SPH (Smooth Particle Hydrodynamics) mesh-free method. It has been proved that a Lagrangian formulation removes completely the instability (but zero energy modes exist). In fact, Lagrangian SPH works even better than the Finite Element Method in problems involving distortions. Nevertheless, in problems with very large distortions a Lagrangian formulation will need of frequent updates of the reference configuration. When such updates are incorporated then zero energy modes are more likely to be activated. When few updates are carried out the error is small but when updates are performed frequently the solution is completely spoilt because of the zero energy modes. In this thesis an updated Lagrangian formulation is developed. It allows to carry out updates of the reference configuration without suffering the appearance of spurious modes. To update the Lagrangian formulation an incremental approach is used: an intermediate configuration will be the new reference configuration for the next time steps. It has been observed that this updated formulation suffers from similar numerical fracture to the Eulerian case. A modal analysis has proven that there exist zero energy modes. In the paper the updated Lagrangian method is exposed in detail, a stability analysis is performed and finally a stabilization technique is incorporated to preclude spurious modes.
34
Arakelyan, Avetik. "The Finite Difference Methods for Multi-phase Free Boundary Problems." Doctoral thesis, KTH, Matematik (Avd.), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-33543.
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This thesis consist of an introduction and four research papers concerning numerical analysis for a certain class of free boundary problems. Paper I is devoted to the numerical analysis of the so-called two-phase membrane problem. Projected Gauss-Seidel method is constructed. We prove general convergence of the algorithm as well as obtain the error estimate for the finite difference scheme. In Paper II we have improved known results on the error estimates for a Classical Obstacle (One-Phase) Problem with a finite difference scheme. Paper III deals with the parabolic version of the two-phase obstacle-like problem. We introduce a certain variational form, which allows us to definea notion of viscosity solution. The uniqueness of viscosity solution is proved, and numerical nonlinear Gauss-Seidel method is constructed. In the last paper, we study a numerical approximation for a class of stationary states for reaction-diffusion system with m densities having disjoint support. The proof of convergence of the numerical method is given in some particular cases. We also apply our numerical simulations for the spatial segregation limit of diffusive Lotka-Volterra models in presence of high competition and inhomogeneous Dirichlet boundary conditions.QC 20110510
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Parkinson, Steven. "Modelling free-surface flow with bathymetry variation using spectral methods." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.570859.
Full textAbstract:
Generation of electricity, by harnessing tidal currents with turbines, has the potential to contribute to a more sustainable future. However, knowledge of the fluid velocity, at a certain depth, is required in order to predict the available energy resource. Therefore, a modelling framework is described, which is computationally efficient, with only a few tunable parameters, and yields good results in comparison to experimental work and computational fluid dynamics. Existing approximate analysis methods, which describe fluid flow over varying topography are discussed. It is found that these theories are incapable of satisfying our objective. From field measurements of a tidal channel, a model is developed that describes turbulent free-surface flow over varying bathymetry. The flow is modelled using the steady incompressible two- dimensional shallow water equations. Turbulence closure is achieved using the eddy-viscosity model. The equations are solved using spectral methods. Convergence of the method is tested by varying the number of modes and the mixing parameterisation. A comparison with experimental work and a regional scale ocean circulation model, for free-surface flow over a ridge, is made. Close agreement is found using pseudo spectral methods. The Galerkin method does not achieve the same level of accuracy. In addition, numerical instability is found to occur on the downstream face of the ridge. However, provided the bathymetry gradients are sufficiently shallow, the solution procedure performs well. A three-dimensional model is achieved by calculating the two-dimensional depth-averaged flow through a tidal channel. Upon calculation of the streamlines from the depth-averaged flow solution, the vertical structure of the flow is calculated. The full flow profile can be obtained by piecing together outputs from each streamline. This is then compared to a one-dimensional hydraulic model where good agreement is found. Finally, flow for a real channel is computed.
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Woods, Christopher J. "The development of free energy methods for protein-ligand complexes." Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396741.
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Wall, Ian. "New simulation methods for the prediction of binding free energies." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313217.
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Pihlblad, Alma. "Development and comparison of bioanalytical methods to measure free analyte." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-413669.
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Free analyte is measured to be able to understand the pharmacological effects of a drug in the body, the binding to its ligand, and the effective drug level among other things. Thereby, it is important with correct measurements of free analyte, although it is not that easy to achieve since overestimations can occur. In this project, several immunoassays were developed for the bioanalytical methods Gyrolab and ELISA to measure free analyte, where the biotherapeutics Avastin® and Lucentis®, and the ligand VEGF were used as analytes. One difference between the methods is the short contact time of just a few seconds for Gyrolab compared to the sample incubation time of a couple of hours for ELISA. One difference between the antibodies is that Lucentis is an affinity-matured Fab region, and therefore, has a stronger affinity to VEGF compared to Avastin. When free Avastin was measured, the difference was significant, with ELISA estimating higher concentrations compared to Gyrolab. However, this was not the case for all assays. In some cases, this was probably due to differences between the methods that could not be seen. Otherwise, the results with no difference between the methods, when measuring free analyte with Lucentis as the drug, were expected due to the stronger affinity and longer halftime of dissociation. However, the difference with the longer sample incubation time for ELISA compared to the short contact time for Gyrolab seems to influence the measurement of free analyte, depending on the affinity of the components being measured.
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Zhang, Jiapu. "Derivative-free hybrid methods in global optimization and their applications." Thesis, University of Ballarat, 2005. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/34054.
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In recent years large-scale global optimization (GO) problems have drawn considerable attention. These problems have many applications, in particular in data mining and biochemistry. Numerical methods for GO are often very time consuming and could not be applied for high-dimensional non-convex and / or non-smooth optimization problems. The thesis explores reasons why we need to develop and study new algorithms for solving large-scale GO problems .... The thesis presents several derivative-free hybrid methods for large scale GO problems. These methods do not guarantee the calculation of a global solution; however, results of numerical experiments presented in this thesis demonstrate that they, as a rule, calculate a solution which is a global one or close to it. Their applications to data mining problems and the protein folding problem are demonstrated.Doctor of Philosophy
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Shola, Peter Bamidele. "Numerical solution of a free-boundary viscous flow." Thesis, University of Essex, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.256393.
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Muthedath, Premkumar. "Numerical study of nonlinear free-surface flows." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-07212009-040300/.
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Dobie, Christopher George. "A Study of Bulk Free-Radical Photo Copolymerisation and Surfactant Free Emulsion Polymerisation Using Intensified Processing Methods." Thesis, University of Newcastle Upon Tyne, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512198.
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Artale, Valeria. "Level-Set Ghost Fluid Methods for Free Boundary Problems in Incompressible Euler and Navier-Stokes Equations." Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10761/1106.
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The present work is devoted to the study of free boundary problems for Euler and Navier-Stokes equations in primitive variables. The goal of the present work is to elaborate a methodology for numerical modeling of all kinds of incompressible viscous fluids, having in mind possible application to deep water, lava flow simulation and crust formation.
Our approach could be essentially divided in three fundamental components: finite difference for spatial approximation, second order accurate method for temporal discretization and level set methods for boundary representation.
The domain is discretized by a regular Cartesian grid. The boundary is described by level set methods. In this context the boundary is seen as a zero level set of a specific function. Navier-Stokes equations is solved starting from Semi-Lagrangian methods, achieving second order accuracy in time and space. Resolution of Navier-Stokes equations allows a Poisson problem for pressure as an intermediate step. This is solved by multigrid methods. The velocity and the pressure are computed by solving a single implicit system solved iteratively.
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Refsnæs, Runar Heggelien. "Matrix-Free Conjugate Gradient Methods for Finite Element Simulations on GPUs." Thesis, Norges Teknisk-Naturvitenskaplige Universitet, Institutt for fysikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10826.
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A block-structured approach for solving 2-dimensional finite element approximations of the Poisson equation on graphics processing units(GPUs) is developed. Linear triangular elements are used, and a matrix-free version of the conjugate gradient method is utilized for solving test problems with over 30 million elements. A speedup of 24 is achieved on a NVIDIA Tesla C1060 GPU when compared to a serial CPU version of the same solution approach, and a comparison is made with previous GPU implementations of the same problem.
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Akteke, Basak. "Derivative Free Optimization Methods: Application In Stirrer Configuration And Data Clustering." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606591/index.pdf.
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Recent developments show that derivative free methods are highly demanded by researches for solving optimization problems in various practical contexts.
Although well-known optimization methods that employ derivative information can be very effcient, a derivative free method will be more effcient in cases
where the objective function is nondifferentiable, the derivative information is
not available or is not reliable. Derivative Free Optimization (DFO) is developed
for solving small dimensional problems (less than 100 variables) in which
the computation of an objective function is relatively expensive and the derivatives
of the objective function are not available. Problems of this nature more
and more arise in modern physical, chemical and econometric measurements
and in engineering applications, where computer simulation is employed for the
evaluation of the objective functions.
In this thesis, we give an example of the implementation of DFO in an approach
for optimizing stirrer configurations, including a parametrized grid generator,
a flow solver, and DFO. A derivative free method, i.e., DFO is preferred because
the gradient of the objective function with respect to the stirrer&rsquos design variables is not directly available. This nonlinear objective function is obtained from the flow field by the flow solver. We present and interpret numerical results of this implementation. Moreover, a contribution is given to a survey and a distinction of DFO research directions, to an analysis and discussion of these. We also state a derivative free algorithm used within a clustering algorithm in combination with non-smooth optimization techniques to reveal the effectiveness of derivative free methods in computations. This algorithm is applied on some data sets from various sources of public life and medicine. We compare various methods, their practical backgrounds, and conclude with a summary and outlook. This work may serve as a preparation of possible future research.
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Cossins, Benjamin Philip. "The Use of Fast Free Energy Methods in Rational Drug Design." Thesis, University of Southampton, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485031.
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The computationally demanding nature and lack of generality of free energy methods are the main barriers to their common place use in rational drug design. This study investigates the possibility of producing protocols to accurately calculate the binding free energy of protein-ligand complexes more efficiently than presently established methods, using large scale distributed computing. There has been an explosion of useful nonequilibrium work methods recently, mainly due to the discovery of the Jarzynski equilibrium [Jarzynski(1997b)]. After an indepth investigation of these methods a subset, all with the possibility of large scale parallelisation, was chosen for further study. Also, replica exchange fast growth (REFG), was developed, a method which combines replica exchange and fast growth methods in a similar way to replica exchange thermodynamic integration (RET!) [Woods et al.(2003a)Woods, Essex & King]. These methods of interest-were applied to a large number of harmonic oscillator systems and compared to the established me~hod TI. Those methods deemed to perform best were then applied to some simple solute-solvent test systems and compared to the established method RET!. The best performing method from these studies was then.compared to RET! for the calculation of relative binding free energies of two sets of cogeneric inhibitors bound to their receptor proteins. REFG was found to perform as well as RET! and produce constantly predictive results. REFG was able to produce these results in significantly less wall clock time by using large scale distributed computing.
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Mjörner, Patrik, and Erik Bosrup. "Alternative methods of financing software : Replacing illegal copying with free copying." Thesis, Blekinge Tekniska Högskola, Avdelningen för programvarusystem, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-4177.
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The software industry’s largest and most severe problem is software piracy. Most attempts to stop illegal copying of software have failed. Alternative ways to remove software piracy must therefore be discovered and some are already being used. These ways include alternative methods of financing software products instead of trying to stop illegal copying. The alternative methods use the low cost of software duplication as an advantage to increase sales instead of seeing it as a problem. This requires a change in the business model to focus on other revenue sources than per-copy fees. Many different alternative financing methods exist. These are suitable under different conditions and there is no universal solution. The methods all have one thing in common. The user can legally copy and use the software product without purchasing a license. All have different positive and negative effects on the user and this can create the opportunity to use several business models to cater different market segments.Mjukvaruindustrins största och allvarligaste problem är piratkopiering. De flesta försökt att få bukt med piratkopieringsproblemet har misslyckats. Alternativa metoder för att försöka lösa piratkopieringsproblemet måste därför hittas. Ett alternativt sätt att lösa piratkopieringsproblemet på är med hjälp av alternativa finansieringsmetoder för programvara. De alternativa finansieringsmetoderna använder sig av mjukvaras speciella egenarter som extremt låg reproduktionskostnad och enkelheten att enkelt göra perfekta kopior. Dessa alternativa finansieringsmetoder försöker hitta andra källor för inkomst än försäljningen av licenser. Många alternativa finansieringsmetoder finns. Dessa är tillämpbara och lämpliga i olika situationer och ingen universell lösning finns. Det dessa metoder har gemensamt är att programvarans användare fritt kan kopiera programvaran och använda den utan att behöva köpa en licens. Då de alternativa finansieringsmetoderna har olika positiva och negative påverkningar på sina användare ges tillfälle att kunna kombinera modeller.
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Hasan, Salah. "Methods to extend the mold free shelf life of pizza crusts." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29712.pdf.
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Schug, Alexander. "Free energy simulations using stochastic optimization methods for protein structure prediction." Karlsruhe : FZKA, 2005. http://bibliothek.fzk.de/zb/berichte/FZKA7171.pdf.
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Ḥasan, Ṣalāḥ 1964. "Methods to extend the mold free shelf life of pizza crusts." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27337.
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In this research, initial studies were done to determine the effect of various methods of presentation involving chemical preservatives, water activity ($ rm a sb{w}$), and modified atmosphere packaging (MAP) on mold growth in an agar model system. Results showed that preservatives could completely inhibit mold growth for 2-40d depending on concentration and pH used. Gas packaging (60% or 80% CO$ sb2$), oxygen absorbents, alone or in combination with potassium sorbate, could also inhibit mold growth for $>$40d at ambient storage temperature using a Response Surface Methodology (RSM) approach.The effects of various methods of applying potassium sorbate into pizza crusts via direct incorporation into the batter, surface spraying, and impregnation of packaging material with potassium sorbate to control mold spoilage of pizza crusts were also investigated. Results showed that the antimicrobial effect of potassium sorbate was negligible when the packaging material was impregnated with the inhibitor but more pronounced when it was incorporated directly into the dough or sprayed onto the product's surface. The inhibitory effect of potassium sorbate increased as both the pH and the inoculum level decreased.
Shelf life studies using low concentrations of potassium sorbate (1000 and 2000 p.p.m.) and MAP, alone and in combination with each other, showed that potassium sorbate, gas packaging or oxygen absorbents (Ageless FX) could extend the shelf life of pizza crusts and decrease the growth rate of molds, bacteria and yeast. Furthermore, when pizza crusts were packaged in 60% CO$ sb2$ or with an oxygen absorbent, in combination with potassium sorbate (1000-2000 p.p.m.), a shelf life of 42d was possible without compromising the sensory shelf life of the product. (Abstract shortened by UMI.)