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Young, Todd Ray. "Saddle-node bifurcations with homoclinic orbits." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/29855.
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Ladenheim, Scott Aaron. "Constraint Preconditioning of Saddle Point Problems." Diss., Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/319906.
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MathematicsPh.D.
This thesis is concerned with the fast iterative solution of linear systems of equations of saddle point form. Saddle point problems are a ubiquitous class of matrices that arise in a host of computational science and engineering applications. The focus here is on improving the convergence of iterative methods for these problems by preconditioning. Preconditioning is a way to transform a given linear system into a different problem for which iterative methods converge faster. Saddle point matrices have a very specific block structure and many preconditioning strategies for these problems exploit this structure. The preconditioners considered in this thesis are constraint preconditioners. This class of preconditioner mimics the structure of the original saddle point problem. In this thesis, we prove norm- and field-of-values-equivalence for constraint preconditioners associated to saddle point matrices with a particular structure. As a result of these equivalences, the number of iterations needed for convergence of a constraint preconditioned minimal residual Krylov subspace method is bounded, independent of the size of the matrix. In particular, for saddle point systems that arise from the finite element discretization of partial differential equations (p.d.e.s), the number of iterations it takes for GMRES to converge for theses constraint preconditioned systems is bounded (asymptotically), independent of the size of the mesh width. Moreover, we extend these results when appropriate inexact versions of the constraint preconditioner are used. We illustrate this theory by presenting numerical experiments on saddle point matrices that arise from the finite element solution of coupled Stokes-Darcy flow. This is a system of p.d.e.s that models the coupling of a free flow to a porous media flow by conditions across the interface of the two flow regions. We present experiments in both two and three dimensions, using different types of elements (triangular, quadrilateral), different finite element schemes (continuous, discontinuous Galerkin methods), and different geometries. In all cases, the effectiveness of the constraint preconditioner is demonstrated.
Temple University--Theses
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Enniss, Harris. "A Refined Saddle Point Theorem and Applications." Scholarship @ Claremont, 2012. https://scholarship.claremont.edu/hmc_theses/33.
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Under adequate conditions on $g$, we show the density in $L^2((0,\pi),(0,2\pi))$ of the set of functions $p$ for which \begin{equation*} u_{tt}(x,t)-u_{xx}(x,t)= g(u(x,t)) + p(x,t) \end{equation*} has a weak solution subject to \begin{equation*} \begin{aligned} u(x,t)&=u(x,t+2\pi)\\ u(0,t)&=u(\pi,t)=0. \end{aligned} \end{equation*}
To achieve this, we prove a Saddle Point Principle by means of a refined variant of the deformation lemma of Rabinowitz.
Generally, inf-sup techniques allow the characterization of critical values by taking the minimum of the maximae on some particular class of sets. In this version of the Saddle Point Principle, we introduce sufficient conditions for the existence of a saddle-structure which is not restricted to finite-dimensional subspaces.
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Tahar, Guillaume. "Saddle connections of flat surfaces with poles." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC163/document.
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Dans cette thèse, nous étudions plusieurs problèmes géométriques concernant les liens-selles de surfaces plates définies par des formes différentielles méromorphes ayant des pôles de degré arbitrairement grand. Dans le cas des 1-formes holomorphes, les surfaces sont d'aire finie et ont une infinité de liens-selles. Au contraire, pour les 1-formes méromorphes ainsi que les différentielles d'ordre supérieur (quadratiques et au delà) ayant des pôles dont le degré est suffisamment grand, les surfaces sont d'aire infinie et il est courant que le nombre de liens-selles soit fini. Nous étudions trois problèmes au sujet de telles surfaces. Le premier problème est la caractérisation des strates de différentielles dont les surfaces plates correspondantes ont toujours un nombre fini de liens-selles. Nous sommes parvenus à réduire le problème à un simple critère combinatoire relatif au profil de singularités de la strate. Pour ce premier problème, nous nous plaçons dans le cadre le plus général possible : celui des k-différentielles (de la forme f(z)dz^{k}) ayant au moins un pôle d'ordre supérieur ou égal à k. Le deuxième problème est celui de la caractérisation des groupes de Veech des surfaces plates avec pôles. Dans le cas classique des surfaces de (demi)-translation, il s'agit d'un problème très difficile. Ici, au contraire, la rigidité induite par la présence de pôles permet de donner une réponse complète. Enfin, nous proposons une caractérisation complète des familles de nombres complexes pouvant apparaître comme résidus aux pôles d'une différentielle méromorphe appartenant à une strate donnée. Ainsi, la géométrie plate permet de donner une réciproque au théorème des résidus dans laquelle on contrôle la multiplicité des singularités. Ce dernier résultat est le fruit d'une collaboration avec Quentin GendronIn this thesis, we consider several geometric problems about saddle connections of flat surfaces defined by meromorphic differentials with poles of arbitrarily large degree. In the case of holomorphic 1-forms, surfaces are of finite area an have infinitely many saddle connections. On the contrary, if we consider meromorphic 1-forms and differentials of higher orders (quadratic and beyond) with at least one pole whose degree is large enough, flat surface are of infinite area and their number of saddle connections may be finite. We study three problems about such surfaces. The first problem is the characterization of the strata of differentials such that the corresponding flat surfaces always have a finite number of saddle connections. We achieved to reduce the problem to a to single combinatorial criterium depending on the singularity pattern of the stratum. When we deal with this problem, we adopt the most general framework of k-differentials (of the form f(z)dz^{k}) with at least one pole of order at least k. The second problem is characterization of Veech groups of flat surfaces with poles. In the classical case of (half)-translation surfaces, it is a very difficult problem. Here, rigidity induced by the poles makes possible to provide a complete answer. Finally, we provide a complete characterization of the families of complex numbers that can appear as residues at the poles of a meromorphic differential belonging to a gien stratum. Thus, flat geometry provides a reciprocal to the residue theorem in which we control the multiplicities of the singularities. This last result is the product of a collaboration with Quentin Gendron
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Claus, Lisa [Verfasser]. "Multigrid smoothers for saddle point systems / Lisa Claus." Wuppertal : Universitätsbibliothek Wuppertal, 2019. http://d-nb.info/1194196829/34.
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Schroeter, Klaus-Peter. "A business plan for Saddle Hill fishing company." Thesis, Stellenbosch : Stellenbosch University, 1994. http://hdl.handle.net/10019.1/72020.
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Thesis (MBA) -- Stellenbosch University, 1994.Stellenbosch University. Faculty of Economic and Management Sciences. University of Stellenbosch Business School.
ENGLISH ABSTRACT: The trawler industry is on the brink of proserity. This progress will result in both the trawler industry and the state amending their policy formulation to adapt to changing circumstances. The government will, for instance, have to consider subsidising the building of boats and the establishment of infrastructure, which is becoming increasingly expensive, and is already being done abroad. On the other hand, planning and organisation of trawler industries will have to be done in close consultation with the government, who is in fact responsible for fish sources. This will result in an enormous responsibility for the government, who will have to improve research on fish resources and availability of fish species. This information is of the utmost importance to trawler industries that have to plan for future production and sales. The progress of trawler industries is not just influenced by the government but also by their own internal planning. Future development will definitely require more capital outlay from industries in the form of modernized catching and processing equipment. In the present-day highly competitive and rapidly changing environment it is difficult to generate funds if no assets can be shown. Smaller enterprises that are not financially strong enough to establish their own infrastructure, should consider amalgamation with other small or large enterprises. The author is of the opinion that the possibility to obtain the necessary funds for the establishment of an own infrastructure without the required security, should exist with an efficient business plan. Insufficient planning in new enterprises is possibly the major contributing factor towards failure. Without investing capital at this early stage, new ideas can be tested on paper by means of planning. A literature study was undertaken to evaluate the opinions of various authors on a business plan. Factors for success in a good business plan were highlighted as follows: keep the business plan brief; do not over-diversify the enterprise; avoid describing technical products and manufacturing process in a way only comprehensible by an expert; organise and wrap the business plan effectively; the plan must be future orientated; avoid exageration; highlight critical risks; discuss and include any relevant problems; take care that the business plan is as complete as possible; and identify the target market and avoid ambiguous, vague and unrealistic statements. A business plan has been compiled for the purpose of this study. using the preceding information. Finally, a recommendation regarding future capital absorption and extension has been made to the company concerned.
AFRIKAANSE OPSOMMING: Die treilbedryf staan op die drumpel van vooruitgang. Hierdie vooruitgang gaan meebring dat beide die treilondernemings en die Staat hul beleidsformulering sodanig sal moet verander om aan Ie pas by die veranderende omstandighede. Die Staat sal byvoorbeeld daaraan moet dink om die bou van bote, wat at hoe duurder word, en die oprigting van infrastruktuur te subsidieer. iets wat weI in die buiteland gedoen word. Aan die anderkant sal beplanning en organisasie van treilondememings in nouer kontak met die Staat, wat verantwoordelik is vir die beheer van visbronne, moet geskied. Dit plaas 'n geweldige taak op die skouers van die Staat, want by sal beter navorsing moet doen oor visbronne en die beskikbaarheid van vissoorte. Hierdie inligting is van groot belang vir treilondememings wat moet beplan vir produksie en verkope in die toekoms. Die vooruitgang van treilondememings word egteT nie slegs deuT die Staat beinvloed nie, maar ook deur hul eie interne beplanning. Toekomstige ontwikkeling gaan definitief meer kapitaal van ondememings verg in die vorm van beter en meer modeme vang- en verwerkingstoerusting. In vandag se hoogs kompeterende en snelveranderende omgewing is dit moeilik om fondse te genereer veral as geen bates getoon kan word nie. Klein ondememings wat nie kapitaalkragtig genoeg is om 'n eie infrastruktuur op te rig nie, moet dit gewoonlik oorweeg om met ander klein of groot ondememings te amalgameer. Die navorser is van mening dat met behulp van 'n goeie besigheidsplan daar wei 'n moontlikheid behoort te bestaan om die nodige fondse, sonder die vereiste sekuriteit, te bekom om sodoende 'n eie infrastruktuur op te rig. 'n Gebrek aan beplanning by nuwe ondernemings is waarskynlik een van die grootste enkele bydraende faktore tot mislukking. Deur beplanning kan nuwe idees op papier op proef gestel word sonder om kapitaal op hierdie vroee stadium te investeer. 'n Literatuur ondersoek is onderneem om verskillende skrywers se menings ten opsigte van 'n besigheidsplan te evalueer. Suksesfaktore vir 'n goeie besigheidsplan is dan ook uitgelig: • hou die besigheidsplan kort; moet nie die onderneming oor-diversifiseer nie; venny dit om die tegniese produkte en vervaardigingsproses op so 'n manier, dat net 'n kundige dit kan verstaan, te beskryf; organiseer en verpak die besigheidsplan doelmatig; orienteer die plan volgens die toekoms; venny oordrewendheid; lig kritieke risiko's uit; bespreek en sluit enige toepaslike probleme in; sorg dat die besigheidsplan so kompleet as moontlik is; identifiseer die teikenmark en venny dubbelsinnige, vae en onwerklike stellings. Met hierdie kennis as agtergrond is 'n besigheidsplan opgestel wat vir die doel van hierdie studie gebruik is. Ten slotte is 'n aanbeveling aan die betrokke maatskappy gemaak met die oog op toekomstige kapitaalopneming en uitbreiding.
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ENGVALL, THERESE. "Pressure sensitive textiles for integration in saddle pads." Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-17397.
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: In this thesis, capacitive textile pressure sensors have been developed. The sensors were meant to be integrated into saddle pads and be able to measure the pressure between the saddle and horse. The aim of the thesis was to create a theoretical and practical based map on how a textile pressure sensor can be made. Capacitance was found to be the most suitable pressure sensitive technique to be implemented in a textile structure. The project was divided into two cycles, where the first cycle consisted of laminating capacitive textile pressure sensors of readymade fabrics in different thicknesses and sizes. After testing the pressure sensitivity of these laminates, it was concluded that a thin fabric with some compressibility was sufficient for making a textile capacitive pressure sensor. However, the area cannot be too small. The second cycle consisted of weaving capacitive pressure sensors as three layer structures. The pressure sensitivity of the sensors and the effect of moisture were tested. The results showed that most of the woven sensors were able to sense a 50g change in weight even after a 700g load was put on. The moisture and water tests showed that the pressure sensors must be protected from water and moisture. It was also discovered that there is a lack of knowledge in how textile structures and fibres behave under compression and release. Models of how textiles behave during pressure are needed to do correct transformations between compression and pressure and predict how the textile will behave during different pressures.Program: Masterutbildning i textilteknik
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Eksell, Per. "Imaging of bone spavin : a radiographic and scintigraphic study of degenerative joint disease in the distal tarsus in Icelandic horses /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5922-2.pdf.
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Axelsson, Mats. "Bone spavin : clinical and epidemiological aspects of degenerative joint disease in the distal tarsus in Icelandic horses /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5918-4.pdf.
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Borquez, Caballero Rodrigo Edgardo. "Calculating the Distance to the Saddle-Node Bifurcation Set." Thesis, KTH, Elektriska energisystem, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-119236.
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A power system will experience voltage collapse when the loads increase up to a certain critical limit, where the system physically cannot support the amount of connected load. This point identified as a Saddle- Node Bifurcation (SNB), corresponds to a generic instability of parameterized differential equation models and represents the intersection point where different branches of equilibria meet. At this point the jacobian matrix of the system is singular and the system loses stability bringing the typical scenario of voltage collapse. To prevent voltage instability and collapse, the computation of the closest distance from a present operating point to the saddle-node bifurcation set can be used as a loadability index useful in power system operation and planning. The power margin is determined by applying the iterative or direct method described in [16]. Numerical examples of both methods applied to IEEE 9-bus system and IEEE 39-bus system shows that the iterative method is more reliable although it requires a longer computation time. The stability of the system is negatively affected in two ways when generators reach their reactive power limits: the voltage stability margin is deteriorated, or immediate voltage instability and collapse is produced.
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Chan, Lung-chak. "Some analyses of HSS preconditioners on saddle point problems." View the Table of Contents & Abstract, 2006. http://sunzi.lib.hku.hk/hkuto/record/B36584939.
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Chan, Lung-chak, and 陳龍澤. "Some analyses of HSS preconditioners on saddle point problems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B37726900.
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Metsch, Bram [Verfasser]. "Algebraic Multigrid (AMG) for Saddle Point Systems / Bram Metsch." Bonn : Universitäts- und Landesbibliothek Bonn, 2013. http://d-nb.info/1045276421/34.
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Davenport, N. M. "Homoclinic bifurcation and saddle connections for Duffing type oscillators." Thesis, Keele University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381450.
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He, Yunlong. "Accelerated algorithms for composite saddle-point problems and applications." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53069.
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This dissertation considers the composite saddle-point (CSP) problem which is motivated by real-world applications in the areas of machine learning and image processing. Two new accelerated algorithms for solving composite saddle-point problems are introduced.
Due to the two-block structure of the CSP problem, it can be solved by any algorithm belonging to the block-decomposition hybrid proximal extragradient (BD-HPE) framework. The framework consists of a family of inexact proximal point methods for solving a general two-block structured monotone inclusion problem which, at every iteration, solves two prox sub-inclusions according to a certain relative error criterion. By exploiting the fact that the two prox sub-inclusions in the context of the CSP problem are equivalent to two composite convex programs, the first part of this dissertation proposes a new instance of the BD-HPE framework that approximately solves them using an accelerated gradient method. It is shown that this new instance has better iteration-complexity than the previous ones.
The second part of this dissertation introduces a new algorithm for solving a special class of CSP problems. The new algorithm is a special instance of the hybrid proximal extragradient (HPE) framework in which a Nesterov's accelerated variant is used to approximately solve the prox subproblems. One of the advantages of the this method is that it works for any constant choice of proximal stepsize. Moreover, a suitable choice of the latter stepsize yields a method with the best known (accelerated inner) iteration complexity for the aforementioned class of saddle-point problems.
Experiment results on both synthetic CSP problems and real-world problems show that the two method significantly outperform several state-of-the-art algorithms.
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Fuhrmann, G., M. Gröger, and T. Jäger. "Non-smooth saddle-node bifurcations II: Dimensions of strange attractors." Cambridge University Press, 2018. https://tud.qucosa.de/id/qucosa%3A70708.
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We study the geometric and topological properties of strange non-chaotic attractors created in non-smooth saddle-node bifurcations of quasiperiodically forced interval maps. By interpreting the attractors as limit objects of the iterates of a continuous curve and controlling the geometry of the latter, we determine their Hausdorff and box-counting dimension and show that these take distinct values. Moreover, the same approach allows us to describe the topological structure of the attractors and to prove their minimality.
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Fuhrmann, Gabriel. "Non-smooth saddle-node bifurcations I: existence of an SNA." Cambridge University Press, 2016. https://tud.qucosa.de/id/qucosa%3A70707.
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We study one-parameter families of quasi-periodically forced monotone interval maps and provide sufficient conditions for the existence of a parameter at which the respective system possesses a non-uniformly hyperbolic attractor. This is equivalent to the existence of a sink-source orbit, that is, an orbit with positive Lyapunov exponent both forwards and backwards in time. The attractor itself is a non-continuous invariant graph with negative Lyapunov exponent, often referred to as ‘SNA’. In contrast to former results in this direction, our conditions are C² -open in the fibre maps. By applying a general result about saddle-node bifurcations in skew-products, we obtain a conclusion on the occurrence of non-smooth bifurcations in the respective families. Explicit examples show the applicability of the derived statements.
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Stokes, Jack Wilson. "Saddle point evaluation of communications systems over ideal and wireless channels /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/5877.
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He, Niao. "Saddle point techniques in convex composite and error-in-measurement optimization." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54400.
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This dissertation aims to develop efficient algorithms with improved scalability and stability properties for large-scale optimization and optimization under uncertainty, and to bridge some of the gaps between modern optimization theories and recent applications emerging in the Big Data environment. To this end, the dissertation is dedicated to two important subjects -- i) Large-scale Convex Composite Optimization and ii) Error-in-Measurement Optimization. In spite of the different natures of these two topics, the common denominator, to be presented, lies in their accommodation for systematic use of saddle point techniques for mathematical modeling and numerical processing. The main body can be split into three parts.
In the first part, we consider a broad class of variational inequalities with composite structures, allowing to cover the saddle point/variational analogies of the classical convex composite minimization (i.e. summation of a smooth convex function and a simple nonsmooth convex function). We develop novel composite versions of the state-of-the-art Mirror Descent and Mirror Prox algorithms aimed at solving such type of problems. We demonstrate that the algorithms inherit the favorable efficiency estimate of their prototypes when solving structured variational inequalities. Moreover, we develop several variants of the composite Mirror Prox algorithm along with their corresponding complexity bounds, allowing the algorithm to handle the case of imprecise prox mapping as well as the case when the operator is represented by an unbiased stochastic oracle.
In the second part, we investigate four general types of large-scale convex composite optimization problems, including (a) multi-term composite minimization, (b) linearly constrained composite minimization, (c) norm-regularized nonsmooth minimization, and (d) maximum likelihood Poisson imaging. We demonstrate that the composite Mirror Prox, when integrated with saddle point techniques and other algorithmic tools, can solve all these optimization problems with the best known so far rates of convergences. Our main related contributions are as follows. Firstly, regards to problems of type (a), we develop an optimal algorithm by integrating the composite Mirror Prox with a saddle point reformulation based on exact penalty. Secondly, regards to problems of type (b), we develop a novel algorithm reducing the problem to solving a ``small series'' of saddle point subproblems and achieving an optimal, up to log factors, complexity bound. Thirdly, regards to problems of type (c), we develop a Semi-Proximal Mirror-Prox algorithm by leveraging the saddle point representation and linear minimization over problems' domain and attain optimality both in the numbers of calls to the first order oracle representing the objective and calls to the linear minimization oracle representing problem's domain. Lastly, regards to problem (d), we show that the composite Mirror Prox when applied to the saddle point reformulation circumvents the difficulty with non-Lipschitz continuity of the objective and exhibits better convergence rate than the typical rate for nonsmooth optimization. We conduct extensive numerical experiments and illustrate the practical potential of our algorithms in a wide spectrum of applications in machine learning and image processing.
In the third part, we examine error-in-measurement optimization, referring to decision-making problems with data subject to measurement errors; such problems arise naturally in a number of important applications, such as privacy learning, signal processing, and portfolio selection. Due to the postulated observation scheme and specific structure of the problem, straightforward application of standard stochastic optimization techniques such as Stochastic Approximation (SA) and Sample Average Approximation (SAA) are out of question. Our goal is to develop computationally efficient and, hopefully, not too conservative data-driven techniques applicable to a broad scope of problems and allowing for theoretical performance guarantees. We present two such approaches -- one depending on a fully algorithmic calculus of saddle point representations of convex-concave functions and the other depending on a general approximation scheme of convex stochastic programming. Both approaches allow us to convert the problem of interests to a form amenable for SA or SAA. The latter developments are primarily focused on two important applications -- affine signal processing and indirect support vector machines.
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Gerner, Anna-Lena [Verfasser]. "Certified reduced basis methods for parametrized saddle point problems / Anna-Lena Gerner." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2012. http://d-nb.info/1028004850/34.
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Tani, Mattia <1986>. "Spectral estimates and preconditioning for saddle point systems arising from optimization problems." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6977/.
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In this thesis, we consider the problem of solving large and sparse linear systems of saddle point type stemming from optimization problems. The focus of the thesis is on iterative methods, and new preconditioning srategies are proposed, along with novel spectral estimtates for the matrices involved.
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Nash, David Hugh. "Local loading and saddle supports on cylindrical vessels : some analytical and finite element studies of local load and saddle support problems with a special emphasis towards generating improved design methods." Thesis, University of Strathclyde, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325680.
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Zhu, Huaiping. "Finite cyclicity of graphics through a nilpotent singularity of elliptic or saddle type." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ52202.pdf.
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He, Lijuan. "Multiple phase transition path and saddle point search in computer aided nano design." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53967.
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Functional materials with controllable phase transitions have been widely used in devices for information storage (e.g. hard-disk, CD-ROM, memory) and energy storage (e.g. battery, shape memory alloy). One of the important issues to design such materials is to realize the desirable phase transition processes, in which atomistic simulation can be used for the prediction of materials properties. The accuracy of the prediction is largely dependent on searching the true value of the transition rate, which is determined by the minimum energy barrier between stable states, i.e. the saddle point on a potential energy surface (PES). Although a number of methods that search for saddle points on a PES have been developed, they intend to locate only one saddle point with the maximum energy along the transition path at a time. In addition, they do not consider the input uncertainty associated with the calculation of potential energy. To overcome the limitations, in this dissertation, new saddle point search methods are developed to provide a global view of energy landscape with improved efficiency and robustness. First, a concurrent search algorithm for multiple phase transition pathways is developed. The algorithm is able to search multiple local minima and saddle points simultaneously without prior knowledge of initial and final stable configurations. A new representation of transition paths based on parametric Bézier curves is introduced. A curve subdivision scheme is developed to dynamically locate all the intermediate local minima and saddle points along the transition path. Second, a curve swarm search algorithm is developed to exhaustively locate the local minima and saddle points within a region concurrently. The algorithm is based on the flocking of multiple groups of curves. A collective potential model is built to simulate the communication activities among curves. Third, a hybrid saddle-point search method using stochastic kriging models is developed to improve the efficiency of the search algorithm as well as to incorporate model-form uncertainty and numerical errors associated with density functional theory calculation. These algorithms are demonstrated by predicting the hydrogen diffusion process in FeTiH and body-centered iron Fe8H systems.
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Yao, Xudong. "Minimax methods for finding multiple saddle critical points in Banach spaces and their applications." Diss., Texas A&M University, 2004. http://hdl.handle.net/1969.1/2732.
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This dissertation was to study computational theory and methods for ?nding multiple saddle critical points in Banach spaces. Two local minimax methods were developed for this purpose. One was for unconstrained cases and the other was for constrained cases. First, two local minmax characterization of saddle critical points in Banach spaces were established. Based on these two local minmax characterizations, two local minimax algorithms were designed. Their ?ow charts were presented. Then convergence analysis of the algorithms were carried out. Under certain assumptions, a subsequence convergence and a point-to-set convergence were obtained. Furthermore, a relation between the convergence rates of the functional value sequence and corresponding gradient sequence was derived. Techniques to implement the algorithms were discussed. In numerical experiments, those techniques have been successfully implemented to solve for multiple solutions of several quasilinear elliptic boundary value problems and multiple eigenpairs of the well known nonlinear p-Laplacian operator. Numerical solutions were presented by their pro?les for visualization. Several interesting phenomena of the solutions of quasilinear elliptic boundary value problems and the eigenpairs of the p-Laplacian operator have been observed and are open for further investigation. As a generalization of the above results, nonsmooth critical points were considered for locally Lipschitz continuous functionals. A local minmax characterization of nonsmooth saddle critical points was also established. To establish its version in Banach spaces, a new notion, pseudo-generalized-gradient has to be introduced. Based on the characterization, a local minimax algorithm for ?nding multiple nonsmooth saddle critical points was proposed for further study.
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Basna, Rani. "Edgeworth Expansion and Saddle Point Approximation for Discrete Data with Application to Chance Games." Thesis, Linnaeus University, School of Computer Science, Physics and Mathematics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-8681.
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We investigate mathematical tools, Edgeworth series expansion and the saddle point method, which are approximation techniques that help us to estimate the distribution function for the standardized mean of independent identical distributed random variables where we will take into consideration the lattice case. Later on we will describe one important application for these mathematical tools where game developing companies can use them to reduce the amount of time needed to satisfy their standard requests before they approve any game
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Skufca, Joseph D. "Understanding a chaotic saddle with focus on a 9-variable model of Planar Couette flow." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2897.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Applied Mathematics Program. 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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Bailey, Leif Anthony. "Late Jurassic fault-hosted gold mineralization of the Golden Saddle deposit, White Gold district, Yukon Territory." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44517.
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The Golden Saddle deposit is a lithologically and structurally controlled gold deposit located in west-central Yukon Territory. The deposit is located near the Klondike district, which is best known for its rich history of placer gold mining. The discovery of the Golden Saddle deposit in 2008 was the first significant lode gold discovery in this region. Based upon the geology, structure, and age of the deposit, an amagmatic orogenic model is proposed to describe the genesis of the deposit.
The deposit area is underlain by Late Paleozoic amphibolite-grade metasiliciclastic, metavolcanic, metavolcaniclastic and metaplutonic rocks of the Yukon-Tanana terrane. Mineralization occurs at the intersection between a Jurassic east-striking sinistral transpressional fault system and an older north-striking thrust fault. Metavolcanic and metaplutonic rocks occur in the hanging wall of this thrust fault, whereas metasiliciclastic rocks occur in the footwall. Economic gold mineralization is hosted predominantly by a series of subparallel northeast-striking, northwest-dipping faults within the sinistral transpressional fault system. The gold-hosting faults are complex structures comprising early folds and shears that are crosscut by polyphase quartz-carbonate-sulphide veins, fracture zones, and breccias. Gold and related alteration minerals typically occur in brittle, dilational deformation zones. Some gold-bearing brittle deformation zones are oriented parallel to the fold-axial plane of ductile folds. This textural relationship is indicative of gold mineralization occurring near the brittle-ductile transition.
Gold mineralization is accompanied by a progression of alteration mineral assemblages, vein mineral assemblages, and vein textures. Pre-gold alteration and veins vary by host rock composition, whereas syn-gold alteration and veins are characterized by quartz-carbonate-illite and gold-bearing pyrite. Mineralization is accompanied by enrichment of Au-Ag-Pb-S-Te, with enrichment of other elements dependent upon host rock composition, and variably including As, Ba, Bi, Cu, Hg, Mo, Sb, Se, and Zn. Values of δ³⁴S for hydrothermal pyrite range from –9.8 to 6.8‰, whereas ratios of ²⁰⁸Pb/²⁰⁶Pb and ²⁰⁷Pb/ ²⁰⁶Pb range from 2.043-1.933 and 0.828-0.757, respectively. These sulphur and lead isotopic ratios are interpreted to vary in part based upon host rock composition. The age of mineralization is constrained by ¹⁸⁷Re/¹⁸⁷Os model ages of 163–155 Ma for molybdenite in gold-bearing veins within the deposit.
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Sagnes, Emmanuel. "Influence of DC saddle-field discharge deposition parameters on the structure of hydrogenated amorphous carbon semiconductor." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0008/NQ41501.pdf.
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Masters, Bernard Thomas. "An examination of the neuro-musculo-skeletal health of the horsewoman in relation to saddle design." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302635.
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Scheichl, Robert. "Iterative solution of saddle point problems using divergence-free finite elements with applications to groundwater flow." Thesis, University of Bath, 2000. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341106.
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Leung, Tsan-yan Amy. "A study on the electronic structure of a-C:H deposited using Saddle-field glow-discharge CVD." HKBU Institutional Repository, 1998. http://repository.hkbu.edu.hk/etd_ra/161.
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Mellberg, Anders. "Extension – Operator Environment for ForestHarvesters." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Maskinteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-21855.
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A forest harvester operator is today facing a stressful work environment with a high demand on coordination skills and effectiveness to run the operation with positive economical outcome. The learning phase is very long compared to similar work.The vision for this project was to transform the machine, through intuitive and innovative interface design, into an extension of the operator’s body. In this way it provides higher productivity as well as user friendliness, shorter learning phase and a healthier work situation.This was realized through the use of prior but yet not market available related research. Through market studies, applicable technology already available in other industries was found. The result is a complete seat with controls for a conceptual Gremo harvester realizable in the year 2023.
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Dogan, Gozde. "Development Of A 3-camera Vision System And The Saddle Motion Analysis Of Horses Via This System." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610877/index.pdf.
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One of the purposes of this study is to develop a vision system consisting of 3 inexpensive, commercial cameras. The system is intended to be used for tracking the motion of objects in a large calibration volume, typically 6.5 m. wide and 0.7 m. high. Hence, a mechanism is designed and constructed for the calibration of the cameras.
The second purpose of the study is to develop an algorithm, which can be used to obtain the kinematic data associated with a rigid body, using a vision system. Special filters are implemented in the algorithm to identify the 3 markers attached on the body. Optimal curves are fitted to the position data of the markers after smoothing the data appropriately. The outputs of the algorithm are the position, velocity and acceleration of any point (visible or invisible) on the body and the angular velocity and acceleration of the body. The singularities associated with the algorithm are also determined.
Using the vision setup and the developed algorithm for tracking the kinematics of a rigid body, the motions of the saddles of different horses are investigated for different gaits. Similarities and differences between horses and/or gaits are analyzed to lead to quantitative results. Using the limits induced by the whole body vibration of humans, for the first time in the world, daily, allowable riding time and riding distances are determined for different horses and gaits. Furthermore, novel, quantitative horse comfort indicators are proposed. Via the experiments performed, these indicators are shown to be consistent with the comfort assessment of experienced riders.
Finally, in order to implement the algorithms proposed in this study, a computer code is developed using MATLAB®.
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Chan, Wallace Chun Wai. "Deposition of doped hydrogenated diamond-like amorphous carbon films using a DC saddle-field glow-discharge system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0027/MQ51610.pdf.
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Liswaniso, Danny. "A study of pressure patterns beneath the saddle of riding horses using force sensing array (FSA) technology." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413081.
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Amdouni, Saber. "Numerical analysis of some saddle point formulation with X-FEM type approximation on cracked or fictitious domains." Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0007/document.
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Ce mémoire de thèse à été réalisée dans le cadre d'une collaboration scientifique avec "La Manufacture Française des Pneumatiques Michelin". Il porte sur l'analyse mathématique et numérique de la convergence et de la stabilité de formulations mixtes ou hybrides de problèmes d'optimisation sous contrainte avec la méthode des multiplicateurs de Lagrange et dans le cadre de la méthode éléments finis étendus (XFEM). Tout d'abord, nous essayons de démontrer la stabilité de la discrétisation X-FEM pour le problème d'élasticité linéaire incompressible en statique. Le deuxième axe, qui représente le contenu principal de la thèse est dédié à l'étude de certaines méthodes de multiplicateur de Lagrange stabilisées. La particularité de ces méthodes est que la stabilité du multiplicateur est assurée par l'ajout de termes supplémentaires dans la formulation faible. Dans ce contexte, nous commençons par l'étude de la méthode de stabilisation de Barbosa-Hughes appliquée au problème de contact unilatéral sans frottement avec XFEM cut-off. Ensuite, nous construisons une nouvelle méthode basée sur des techniques de projections locales pour stabiliser un problème de Dirichlet dans le cadre de X-FEM et une approche de type domaine fictif. Nous faisons aussi une étude comparative entre la stabilisation avec la technique de projection locale et la stabilisation de Barbosa-Hughes. Enfin, nous appliquons cette nouvelle méthode de stabilisation aux problèmes de contact unilatéral en élastostatique avec frottement de Tresca dans le cadre de X-FEMThis Ph.D. thesis was done in collaboration with "La Manufacture Française des Pneumatiques Michelin". It concerns the mathematical and numerical analysis of convergence and stability of mixed or hybrid formulation of constrained optimization problem with Lagrange multiplier method in the framework of the eXtended Finite Element Method (XFEM). First we try to prove the stability of the X-FEM discretization for incompressible elastostatic problem by ensured a LBB condition. The second axis, which present the main content of the thesis, is dedicated to the use of some stabilized Lagrange multiplier methods. The particularity of these stabilized methods is that the stability of the multiplier is provided by adding supplementary terms in the weak formulation. In this context, we study the Barbosa-Hughes stabilization technique applied to the frictionless unilateral contact problem with XFEM-cut-off. Then we present a new consistent method based on local projections for the stabilization of a Dirichlet condition in the framework of extended finite element method with a fictitious domain approach. Moreover we make comparative study between the local projection stabilization and the Barbosa-Hughes stabilization. Finally we use the local projection stabilization to approximate the two-dimensional linear elastostatics unilateral contact problem with Tresca frictional in the framework of the eXtended Finite Element Method X-FEM
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Rhodin, Marie. "A biomechanical analysis of relationship between the head and neck position, vertebral column and limbs in the horse at walk and trot /." Uppsala : Dept. of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, 2008. http://epsilon.slu.se/20081.pdf.
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Böger, Lukas [Verfasser], and Holger [Akademischer Betreuer] Steeb. "Saddle-point and minimization principles for diffusion in solids : phase separation, swelling and fracture / Lukas Böger ; Betreuer: Holger Steeb." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2020. http://d-nb.info/1209545128/34.
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Penet, Maxime. "Robust Nonlinear Model Predictive Control based on Constrained Saddle Point Optimization : Stability Analysis and Application to Type 1 Diabetes." Phd thesis, Supélec, 2013. http://tel.archives-ouvertes.fr/tel-00968899.
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This thesis deals with the design of a robust and safe control algorithm to aim at an artificial pancreas. More precisely we will be interested in controlling the stabilizing part of a classical cure. To meet this objective, the design of a robust nonlinear model predictive controller based on the solution of a saddle point optimization problem is considered. Also, to test the controller performances in a realistic case, numerical simulations on a FDA validated testing platform are envisaged.In a first part, we present an extension of the usual nonlinear model predictive controller designed to robustly control, in a sampled-data framework, systems described by nonlinear ordinary differential equations. This controller, which computes the best control input by considering the solution of a constrained saddle point optimization problem, is called saddle point model predictive controller (SPMPC). Using this controller, it is proved that the closed-loop is Ultimately Bounded and, with some assumptions on the problem structure, Input-to State practically Stable. Then, we are interested in numerically solving the corresponding control problem. To do so, we propose an algorithm inspired from the augmented Lagrangian technique and which makes use of adjoint model.In a second part, we consider the application of this controller to the problem of artificial blood glucose control. After a modeling phase, two models are retained. A simple one will be used to design the controller and a complex one will be used to simulate realistic virtual patients. This latter is needed to validate our control approach. In order to compute a good control input, the SPMPC controller needs the full state value. However, the sensors can only provide the value of blood glucose. That is why the design of an adequate observer is envisaged. Then, numerical simulations are performed. The results show the interest of the approach. For all virtual patients, no hypoglycemia event occurs and the time spent in hyperglycemia is too short to induce damageable consequences. Finally, the interest of extending the SPMPC approach to consider the control of time delay systems in a sampled-data framework is numerically explored.
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Chang, Fwu-Ranq. "Optimal Growth and Impatience: A Phase Diagram Analysis." 名古屋大学大学院経済学研究科附属国際経済政策研究センター, 2004. http://hdl.handle.net/2237/11954.
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Katrantsiotis, Christos. "Paleoenvironment and shore displacement since 3200 BC in the central part of the Långhundraleden Trail, SE Uppland." Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-89173.
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In this study, litho-, bio- and chronostratigraphic investigations combined with RTK GPSleveling have been carried out to reconstruct the paleoenvironment in the central part of theLånghundraleden Trail. The area displays four shallow lake basins of varyingmorphologies. The basins are now covered with peat as a result of infilling and overgrowth.The emergence of the saddle-point, i.e. the highest point of the underlying minerogenicsurface, was estimated to have occurred c. BC/AD. The isolation events of two basins, atc.12.4 and c.12.3 m a.s.l. west and east of the saddle-point, were dated to c.AD 20 andc.AD 30, respectively. By combining these isolation data with six previously investigatedbasins a shore displacement curve for the central part of the Långhundraleden Trail and thesurrounding area, i.e. east of the Ekoln basin was constructed. The curve indicates anaverage regressive shore displacement rate of c.6.2 mm/yr since c. 3200 BC. Around 1500BC, this trend was interrupted by a short period of retarded regression, correlated with theL4 event. The isolation ages of the basins in the Långhundraleden Trail appears relativelyyoung when compared to an average shore displacement rate of 5.6 mm/year in thenorthern part of L. Mälaren, west of the Ekoln basin. As the area is dominated by a fissurevalleylandscape, this discrepancy could be attributed to small-scale irregular tectonicmovements, which caused faster uplift rate, i.e. 6.2 mm/year, east of the Ekoln basin.
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Hesse, Janina. "Implications of neuronal excitability and morphology for spike-based information transmission." Doctoral thesis, Humboldt-Universität zu Berlin, 2017. http://dx.doi.org/10.18452/18583.
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Signalverarbeitung im Nervensystem hängt sowohl von der Netzwerkstruktur, als auch den zellulären Eigenschaften der Nervenzellen ab. In dieser Abhandlung werden zwei zelluläre Eigenschaften im Hinblick auf ihre funktionellen Anpassungsmöglichkeiten untersucht: Es wird gezeigt, dass neuronale Morphologie die Signalweiterleitung unter Berücksichtigung energetischer Beschränkungen verstärken kann, und dass selbst kleine Änderungen in biophysikalischen Parametern die Aktivierungsbifurkation in Nervenzellen, und damit deren Informationskodierung, wechseln können. Im ersten Teil dieser Abhandlung wird, unter Verwendung von mathematischen Modellen und Daten, die Hypothese aufgestellt, dass Energie-effiziente Signalweiterleitung als starker Evolutionsdruck für unterschiedliche Zellkörperlagen bei Nervenzellen wirkt. Um Energie zu sparen, kann die Signalweiterleitung vom Dendrit zum Axon verstärkt werden, indem relativ kleine Zellkörper zwischen Dendrit und Axon eingebaut werden, während relativ große Zellkörper besser ausgelagert werden. Im zweiten Teil wird gezeigt, dass biophysikalische Parameter, wie Temperatur, Membranwiderstand oder Kapazität, den Feuermechanismus des Neurons ändern, und damit gleichfalls Aktionspotential-basierte Informationsverarbeitung. Diese Arbeit identifiziert die sogenannte "saddle-node-loop" (Sattel-Knoten-Schlaufe) Bifurkation als den Übergang, der besonders drastische funktionale Auswirkungen hat. Neben der Änderung neuronaler Filtereigenschaften sowie der Ankopplung an Stimuli, führt die "saddle-node-loop" Bifurkation zu einer Erhöhung der Netzwerk-Synchronisation, was möglicherweise für das Auslösen von Anfällen durch Temperatur, wie bei Fieberkrämpfen, interessant sein könnte.Signal processing in nervous systems is shaped by the connectome as well as the cellular properties of nerve cells. In this thesis, two cellular properties are investigated with respect to the functional adaptations they provide: It is shown that neuronal morphology can improve signal transmission under energetic constraints, and that even small changes in biophysical parameters can switch spike generation, and thus information encoding. In the first project of the thesis, mathematical modeling and data are deployed to suggest energy-efficient signaling as a major evolutionary pressure behind morphological adaptations of cell body location: In order to save energy, the electrical signal transmission from dendrite to axon can be enhanced if a relatively small cell body is located between dendrite and axon, while a relatively large cell body should be externalized. In the second project, it is shown that biophysical parameters, such as temperature, membrane leak or capacitance, can transform neuronal excitability (i.e., the spike onset bifurcation) and, with that, spike-based information processing. This thesis identifies the so-called saddle-node-loop bifurcation as the transition with particularly drastic functional implications. Besides altering neuronal filters and stimulus locking, the saddle-node-loop bifurcation leads to an increase in network synchronization, which may potentially be relevant for the initiation of seizures in response to increased temperature, such as during fever cramps.
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Li, Jixin. "Saddle point approximation." 2009. http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.000051043.
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JHAO, YOU-SHENG, and 趙佑昇. "Establishment of Saddle Performance Index Data Base and Bicycle Saddle Design Modification." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/j6a5qc.
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碩士國立雲林科技大學
機械工程系
105
Safety and performance of saddle is very important. Safety of saddle is requested by every country standard with rigorous test procedures, but performance testing of saddle can’t be well-defined. The purpose of the research is to setup a complete saddle data base and test method regard to saddle performance, and provide design side reference in the beginning of the design and use the data base to improve the saddle design. The saddles performance testing method is the comparison result between different saddles, the performance of saddle with regard to cyclist user comfort index and how saddles support cyclist when ridding, and these two things are related to deformation distribution of the saddle. The deformation and hardness of the saddles and the shells are analyzed by the test points planned by this paper. Before the test, saddles details data of geometric size and shape were recorded to provide design side reference in the beginning design process. Using several of models of saddle and shell the test data to setup the database can provide useful and convenient reference on design side. The research is done by a finite element analysis software. The simulation analysis is carried out by using the planning test points in the data base. The simulation analysis of the other shell is compared difference from data base control models with the experimental shell. And if the original shell deformation is larger than data base shell, then change the rib of geometry to reduce deformation of the shell, but change the rib of geometry on the shell will also increase the weight of shell, understanding change the rib of geometry on the shell after correlate with deformation and mass, and then find the best to solution to evaluate the rib of geometry on the shell.
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Thayer, Casey. "Self-portrait as western saddle." 2009. 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:1462731.
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Siefert, Christopher Martin. "Preconditioners for generalized saddle-point problems /." 2006. 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:3223718.
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Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006.Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3915. Adviser: Eric de Sturler. Includes bibliographical references (leaves 117-121) Available on microfilm from Pro Quest Information and Learning.
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Chern, Huey Ling, and 陳惠玲. "Moreau-Rockafellar Formular for Saddle Functions." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/93935221256688410931.
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Greene, Scott. "Constraint at a saddle node bifurcation." 1993. http://catalog.hathitrust.org/api/volumes/oclc/32710270.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1993.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 56-58).
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Liu, Ji-Jung, and 劉繼中. "The Bike Saddle Design with Mechanical Analysis." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/ey67sw.
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碩士國立雲林科技大學
機械工程系
103
Bicycle is a convenient tool in transportation for modern people, such as the highly promoted YouBike. The convenience and comfort of riding is getting more and more remarkable. One of the crucial factors in riding comfort is saddle. The purpose of this study is discussing how to design saddles by means of mechanical analysis. A finite element software named ANSYS workbench by Swanson Analysis System, Inc. is mainly used as simulation software for designers to analyze mode, stress and deformation. It shows designers if resonance happens in riding; if fracture happens because of stress, or if deformation generates discomfort. Therefore, designers can modify the paddles purposefully, so that the cost and time will be saved, and the quality and performance of saddles will be elevated.