Dissertations / Theses: 'Tangent'

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Gargano, John Thomas. "A tangent between spheres." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1327001471.

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Martin, Adrian. "Density bounds and tangent measures." Thesis, University of Sussex, 2013. http://sro.sussex.ac.uk/id/eprint/45279/.

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A major theme in geometric measure theory is establishing global properties, such as rectifiability, of sets or measures from local ones, such as densities or tangent measures. In establishing sufficient conditions for rectifiability it is useful to know what local properties are possible in a given setting, and this is the theme of this thesis. It is known, for 1-dimensional subsets of the plane with positive lower density, that the tangent measures being concentrated on a line is sufficient to imply rectifiability. It is shown here that this cannot be relaxed too much by demonstrating the existence of a 1-dimensional subset of the plane with positive lower density whose tangent measures are concentrated on the union of two halflines, and yet the set is unrectiable. A class of metrics are also defined on R, which are functions of the Euclidean metric, to give spaces of dimension s (s > 1), where the lower density is strictly greater than 21-s, and a method for gaining an explicit lower bound for a given dimension is developed. The results are related to the generalised Besicovitch 1/2 conjecture. Set functions are defined that measure how easily the subsets of a set can be covered by balls (of any radius) with centres in the subset. These set functions are studied and used to give lower bounds on the upper density of subsets of a normed space, in particular Euclidean spaces. Further attention is paid to subsets of R, where more explicit bounds are given.

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Franch, Bullich Jaume. "Flatness, tangent systems and flat outputs." Doctoral thesis, Universitat Politècnica de Catalunya, 1999. http://hdl.handle.net/10803/6730.

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En esta tesis doctoral se presentan diversos métodos para la linealización de sistemas de control no lineales o para el estudio de la platitud. Se utilizan dos aproximaciones diferentes, en concreto: geometría diferencial y álgebra diferencial.

En el marco de álgebra diferencial, se presenta un estudio de los sistemas lineales de control desde la perspectiva de la teoría de módulos. A pesar de que los resultados han sido establecidos previamente por otros autores, algunas demostraciones y ejemplos son originales.

Entre las nuevas demostraciones cabe resaltar la que se refiere a la equivalencia entre sistemas de control lineales en representación de variables de estado, y los módulos sobre un anillo de operadores diferenciales. Los resultados de este estudio son ampliamente utilizados en el desarrollo de otros capítulos de la tesis en los que se usa el álgebra diferencial. En este contexto las principales contribuciones son:

Una nueva demostración del hecho, bien conocido, que la linealización por realimentación estática y la linealización por realimentación dinámica son equivalentes en el caso de sistemas de entrada simple. Para la linealización de este tipo de sistemas, se desarrolla un nuevo algoritmo.

Un procedimiento teórico para linealizar sistemas de entrada múltiple, basado en el cociente de módulos. También se ha hecho un paquete informático para llevar a cabo los cálculos necesarios. Debe mencionarse que este procedimiento es válido para linealizar sistemas mediante realimentación estática, así como para sistemas que sólo puedan linealizarse mediante realimentación dinámica.

Una condición para comprobar si las salidas linealizantes encontradas pueden obtenerse mediante prolongaciones. Como aplicación, se muestran algunos ejemplos de sistemas linealizables por prolongaciones. Algunos de estos sistemas se creían que no eran linealizables mediante esta técnica.

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Whited, Brian Scott. "Tangent-ball techniques for shape processing." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31670.

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Thesis (Ph.D)--Computing, Georgia Institute of Technology, 2010.
Committee Chair: Jarek Rossignac; Committee Member: Greg Slabaugh; Committee Member: Greg Turk; Committee Member: Karen Liu; Committee Member: Maryann Simmons. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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Lokteva, Elizaveta. "On Smooth Knots and Tangent Lines." Thesis, Uppsala universitet, Algebra och geometri, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-354484.

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6

Knight, R. W. "Generalized tangent-disc spaces and Q-sets." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257958.

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Hennion, Benjamin. "Formal loops spaces and tangent Lie algebras." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS160/document.

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L'espace des lacets lisses C(S^1,M) associé à une variété symplectique M se voit doté d'une structure (quasi-)symplectique induite par celle de M.Nous traiterons dans cette thèse d'un analogue algébrique de cet énoncé.Dans leur article, Kapranov et Vasserot ont introduit l'espace des lacets formels associé à un schéma. Il s'agit d'un analogue algébrique à l'espace des lacets lisses.Nous generalisons ici leur construction à des lacets de dimension supérieure. Nous associons à tout schéma X -- pas forcément lisse -- l'espace L^d(X) de ses lacets formels de dimension d.Nous démontrerons que ce dernier admet une structure de schéma (dérivé) de Tate : son espace tangent est de Tate, c'est-à-dire de dimension infinie mais suffisamment structuré pour se soumettre à la dualité.Nous définirons également l'espace B^d(X) des bulles de X, une variante de l'espace des lacets, et nous montrerons que le cas échéant, il hérite de la structure symplectique de X. Notons que ces résultats sont toujours valides dans des cas plus généraux : X peut être un champs d'Artin dérivé.Pour démontrer nos résultats, nous définirons ce que sont les objets de Tate dans une infinie-catégorie C stable et complète par idempotence.Nous prouverons au passage que le spectre de K-théorie non-connective de Tate(C) est équivalent à la suspension de celui de C, donnant une version infini-catégorique d'un résultat de Saito.Dans le dernier chapitre, nous traiterons d'un problème différent. Nous démontrerons l'existence d'une structure d'algèbre de Lie sur le tangent décalé de n'importe quel champ d'Artin dérivé X. Qui plus est, ce tangent agit sur tout quasi-cohérent E, l'action étant donnée par la classe d'Atiyah de E.Ces résultats sont par exemple valides dans le cas d'un schéma X sans hypothèse de lissité
If M is a symplectic manifold then the space of smooth loops C(S^1,M) inherits of a quasi-symplectic form. We will focus in this thesis on an algebraic analogue of that result.In their article, Kapranov and Vasserot introduced and studied the formal loop space of a scheme X. It is an algebraic version of the space of smooth loops in a differentiable manifold.We generalize their construction to higher dimensional loops. To any scheme X -- not necessarily smooth -- we associate L^d(X), the space of loops of dimension d. We prove it has a structure of (derived) Tate scheme -- ie its tangent is a Tate module: it is infinite dimensional but behaves nicely enough regarding duality.We also define the bubble space B^d(X), a variation of the loop space.We prove that B^d(X) is endowed with a natural symplectic form as soon as X has one.To prove our results, we develop a theory of Tate objects in a stable infinity category C. We also prove that the non-connective K-theory of Tate(C) is the suspension of that of C, giving an infinity categorical version of a result of Saito.The last chapter is aimed at a different problem: we prove there the existence of a Lie structure on the tangent of a derived Artin stack X. Moreover, any quasi-coherent module E on X is endowed with an action of this tangent Lie algebra through the Atiyah class of E. This in particular applies to not necessarily smooth schemes X

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Webber, Nicholas Jon. "Local tangent space approximation in canonical quantization." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/38183.

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Fahlaoui, Rachid. "Stabilité du fibré tangent des surfaces algébriques." Paris 11, 1989. http://www.theses.fr/1989PA112170.

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Cette thèse a pour sujet la stabilité du fibré tangent des surfaces algébriques. On y étudie les deux notions de stabilité, à savoir, la stabilité au sens de Mumford-Takemoto et la Tstabilité (ou stabilité au sens de Bogomolov). Pour les surfaces à fibré canonique (resp anti-canonique) positif, l'existence d'une métrique de Kähler-Einstein implique la semistabilité du fibré tangent par rapport à la classe canonique (resp anti-canonique). Si K est positif, une telle métrique existe, ce qui implique la K-semi-stabilité du fibré tangent. Ceci nous conduit à étudier le cas des surfaces à fibré canonique négatif. Nous donnons une démonstration algébrique valable en caractéristique quelconque, de la semi-stabilité du fibré tangent par rapport à la classe anti-canonique. Nous généralisons ce résultat aux surfaces à fibré canonique numériquement négatif vérifiant : si le rang du groupe de Picard de S est 9, alors le système linéaire anticanonique est à modules variables. Puis nous passons à l'étude de la T-stabilité en distinguant trois cas : les surfaces elliptiques, les surfaces à première classe de Chern nulle et les surfaces géométriquement réglées. On caractérise celles dont le fibré tangent est T-semi-stable et dans les deux derniers cas celles dont le fibré tangent est T-stable
This thesis is concerned with the stability of the tangent bundle of algebraic surfaces. We consider two notions of stability: stability in the sense of Mumford-Takemoto and T-stability (Bogomolov stability). For surfaces with positive canonical (resp. Anti-canonical) bundle, the existence of a Kähler-Einstein metric implies the semi-stability of the tangent bundle with respect to the canonical (resp. Anti-canonical) class. If K is positive, such a metric exists, which implies K-semi-stability. This leads us to study the case of surfaces with negative canonical bundle. We give an algebraic proof, valid in any characteristic, of the semi-stability of the tangent bundle with respect to the canonical class. We generalize this result to surfaces with numerically negative canonical bundle satisfying: if the rank of the Picard group is nine, the anti-canonical linear system contains a singular semi-stable curve. Then we turn to T-stability, distinguishing three cases: elliptic surfaces, surfaces with vanishing first Chern class and geometrically ruled surfaces. We characterize the ones for which the tangent bundle is T-semi-stable and, in the last two cases, the ones for which the tangent bundle is T-stable

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Moerters, Peter. "Tangent measure distributions and the geometry of measures." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307661.

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Fernandes, Antonio Ramires. "Robustness and generalisation : tangent hyperplanes and classification trees." Thesis, University of St Andrews, 1997. http://hdl.handle.net/10023/13468.

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The issue of robust training is tackled for fixed multilayer feedforward architectures. Several researchers have proved the theoretical capabilities of Multilayer Feedforward networks but in practice the robust convergence of standard methods like standard backpropagation, conjugate gradient descent and Quasi-Newton methods may be poor for various problems. It is suggested that the common assumptions about the overall surface shape break down when many individual component surfaces are combined and robustness suffers accordingly. A new method to train Multilayer Feedforward networks is presented in which no particular shape is assumed for the surface and where an attempt is made to optimally combine the individual components of a solution for the overall solution. The method is based on computing Tangent Hyperplanes to the non-linear solution manifolds. At the core of the method is a mechanism to minimise the sum of squared errors and as such its use is not limited to Neural Networks. The set of tests performed for Neural Networks show that the method is very robust regarding convergence of training and has a powerful ability to find good directions in weight space. Generalisation is also a very important issue in Neural Networks and elsewhere. Neural Networks are expected to provide sensible outputs for unseen inputs. A framework for hyperplane based classifiers is presented for improving average generalisation. The framework attempts to establish a trained boundary so that there is an optimal overall spacing from the boundary to training points closest to this boundary. The framework is shown to provide results consistent with the theoretical expectations.

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Giles, Flores Arturo. "Spécialisation sur le cône tangent et équisingularité à la Whitney." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2011. http://tel.archives-ouvertes.fr/tel-00631426.

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Cette thèse porte sur l'étude de la géométrie de l'espace de spécialisation φ : (X, 0) → (C, 0) d'un germe de singularité analytique complexe (X, 0) sur son cône tangent (CX,0 , 0) du point de vue de l'équisingularité à la Whitney. L'application φ nous donne une famille plate des germes avec section tel que pour chaque t =! 0 le germe φ−1 (t) est isomorphe à (X, 0) et la fibre spéciale est isomorphe au cône tangent. Le but est de établir des conditions sur les strates de la stratification de Whitney minimale de (X, 0) qui assurent l'équisingularité du germe et son cône tangent, generalisant ainsi le résultat de Lê et Teissier pour les hypersurfaces de C3 qui prouve que l'absence des tangentes exceptionnelles est suffisant. Dans ce travail on montre que cette condition est nécessaire et suffisante dans le cas général pour la strate de codimension zero. L'un des ingrédients clés dans la preuve est la théorie de la dépendance integrale sur des ideaux et des modules développé par Teissier, Lejeune, Gaffney, Kleiman, etc, qu'on rappelle au troisième chapitre et où l'on obtient des résultats spécifiques pour cette situation. Les deux premiers chapitres correspondent aux préliminaires, on commence par rappeller la modification de Nash et l'espace conormal d'un espace analytique plongé dans ses versions absolues et relatives à un morphisme et on donne une description explicite de la relation entre le conormal (Nash) relatif de φ : (X, 0) → (C, 0) et le conormal (Nash) de (X, 0). Dans le deuxième chapitre on définit le diagram normal/conormal, l'auréole du germe (X, 0), les cônes exceptionnelles, et on énonce les résultats principaux correspondant à l'équisingularité à la Whitney en incluant la caractérisation des conditions de Whitney en termes du diagramme normal/conormal.

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David, Chantal. "From discrete tangent fields to global curves : dynamic coverings." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61904.

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Constantin, Elena. "Optimization and flow invariance via high order tangent cones." Ohio : Ohio University, 2005. http://www.ohiolink.edu/etd/view.cgi?ohiou1125418579.

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Nsanzamahoro, Pierre Claver. "Métrique sur le fibré unitaire tangent au plan hyperbolique." Mémoire, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/9469.

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RÉSUMÉ: Toute variété différentiable $M$ admet une métrique dite métrique riemannienne.\\ En définissant $\mathbb{H}=\lbrace z\in\mathbb{C}: Im(z)>0\rbrace$, on peut munir de $\mathbb{H}$ d'une métrique riemannienne $ds^{2}=\frac{dzd\bar{z}}{(Im(z))^{2}}=\frac{dx^{2}+dy^{2}}{y^{2}}$.\\ Muni de cette métrique, $\mathbb{H}$ est une variété riemannienne à la quelle on associe le fibré tangent, $T\mathbb{H}$ ainsi que le fibré unitaire tangent, $T^{1}\mathbb{H}$. Les éléments de $T^{1}\mathbb{H}$ peuvent être exprimés, de façon bijective, en termes des éléments du groupe PSL(2,$\mathbb{R}$) dont l'action sur $T^{1}\mathbb{H}$ est transitive et libre.\\ La métrique définie sur $M$ (en particulier sur $M=\mathbb{H}$) permet de définir sur $TM$ (en particulier sur $T^{1}\mathbb{H}$) une métrique connue sous le nom de métrique de Sasaki.

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Majumdar, Apala. "Liquid crystals and tangent unit-vector fields in polyhedral geometries." Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425119.

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Aujogue, Kelig. "Little Earth Experiment : a journey toward the Earth's Tangent Cylinder." Thesis, Coventry University, 2016. http://curve.coventry.ac.uk/open/items/afbec38d-5613-4c2e-94ed-e3574043a0d4/1.

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This dissertation presents a theoretical contribution on the onset of rotating magneto-convection and a new experimental setup built to study the onset and the development of convection in the Earth Tangent Cylinder (TC). The theoretical contribution is a linear stability analysis of the onset of convection for an electrically conducting fluid in rotation and permeated by a magnetic field. This work highlighted the importance of the magnetic field as it enforces a specific mode of convection at onset for a certain range of parameters. The apparatus was designed to show for the first time experimentally the significant role played by the magnetic field on the flow structures and bring forward the first evidence of a polar vortex in the TC with a quantitative measurement technique such as particle image velocimetry (PIV). In order to reach these goals, the experimental setup consisted in an hemispherical dome filled with a transparent conducting fluid heated at the center, cooled on the outside and spun inside a high external magnetic field. The hemispherical dome is approximatively 30cm diameter. The fluid used is sulphuric acid at 30% mass concentration, because of its conductivity of approximatively 80S/m and its transparency, allowing both interactions with the magnetic field and visualization for PIV measurements. To compensate against the weak conductivity of sulphuric acid we used a unique 10T magnet. As a result, we were able to study the difference in the convective flow between the magnetic and nonmagnetic case. It has been shown that convective structures under a magnetic field at onset become much larger leading to one off axis vortex. Above onset it has also been highlighted that this structure is maintained whereas without magnetic field the flow is very different between onset and developed convection. Indeed at the onset we observe numerous structures that coalesce into one large centered structure far from the onset of convection.

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Reynolds, Gregory Thomas. "On the use of molecular envelopes in medium resolution protein x-ray crystallography." Thesis, University of York, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250621.

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Hindeleh, Firas. "Tangent and cotangent bundles automorphism groups and representations of Lie groups /." See Full Text at OhioLINK ETD Center (Requires Adobe Acrobat Reader for viewing), 2006. http://www.ohiolink.edu/etd/view.cgi?acc_num=toledo1153933389.

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Thesis (Ph.D.)--University of Toledo, 2006.
Typescript. "A dissertation [submitted] as partial fulfillment of the requirements of the Doctor of Philosophy degree in Mathematics." Bibliography: leaves 79-82.

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Jiang, J.-S. "Direct methods and least-squares tangent formula in crystal structure determination." Thesis, University of York, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234963.

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Hindeleh, Firas Y. "Tangent and Cotangent Bundles, Automorphism Groups and Representations of Lie Groups." University of Toledo / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1153933389.

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22

Pumberger, David. "Uniqueness of tangent cones for calibrated 2-cycles and other regularity problems /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17792.

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Mohammadi, Shakiba Fatemeh. "CMOS BASED IMPLEMENTATION OF HYPERBOLIC TANGENT ACTIVATION FUNCTION FOR ARTIFICIAL NEURAL NETWORK." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/theses/2310.

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FATEMEH MOHAMMADI SHAKIBA, for the Master of Science degree in MAJOR Electrical and Computer Engineering, presented on 4/11/2018, at Southern Illinois Uni- versity Carbondale. TITLE: CMOS BASED IMPLEMENTATION OF HYPERBOLIC TANGENT ACTIVA- TION FUNCTION FOR ARTIFICIAL NEURAL NETWORK MAJOR PROFESSOR: Dr.Spyros Tragoudas In this thesis, an efficient implementation for the established hyperbolic tangent acti- vation function is proposed. The efficiency of this design is considered in multiple aspects such as power consumption, simplicity of implementing, compatibility with different designs and accuracy. Considering all of these parameters, CMOS technology is chosen to be used for its implementation. This activation function is designed to resemble its mathematical definition, to reach the highest possible extent. Existing CMOS-based designs for hyperbolic tangent activation function is either power consuming for satisfying a reliable accuracy, or not compatible with both digital and ana- log circuits. Hence, we tried to implement a super fast, low power design to solve these problems. We experimented the shallow and deep neural networks with various parameters for two image processing open datasets, the MNIST and notMNIST with more than 60000 images, to present the classification accuracy of the proposed design. [5, 8] This activation function is suited for current based artificial neural networks architectures. According to symmetry feature of hyperbolic tangent function, we proposed a tricky method to have a very small circuit to simulate just half of the function, which is much faster and needs less power than existing circuits that produce a complete form of hyperbolic tangent.

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Mouzali, Mokhtar. "Conditions suffisantes pour l'existence du cône tangent à un courant positif fermé." Grenoble 1, 1989. http://www.theses.fr/1989GRE10044.

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On se propose dans ce travail d'etudier un probleme souleve par r. Harvey (6) en 1977: un courant theta positif et ferme, admet-il toujours un cone tangent. C. O. Kiselman (8) a montre recemment que la reponse generale est negative: il existe un courant theta =id rond d rond phi de bidegre (1, 1), ou phi est une fonction plurisousharmonique, qui n'admet pas de cone tangent. M. Blel (2) a obtenu une condition suffisante pour l'existence d'une limite pour les homothetiques de theta , par les homotheties de rapport r>0. Nous etendons ici cette condition suffisante au cas des homotheties de rapport complexe, puis nous donnons une deuxieme condition suffisante plus naturelle. Bien que les deux conditions soient apparentees, nous montrerons par des exemples qu'aucune des deux n'entraine l'autre, ce qui prouve aussi qu'elles ne sont pas necessaires

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Doyle, Alexander Benjamin. "Algorithms and computational techniques for robot path planning." Thesis, Bangor University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295278.

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Liu, Jie. "Géométrie des variétés de Fano : sous-faisceaux du fibré tangent et diviseur fondamental." Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4038/document.

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Cette thèse est consacrée à l'étude de la géométrie des variétés de Fano complexes en utilisant les propriétés des sous-faisceaux du fibré tangent et la géométrie du diviseur fondamental. Les résultats principaux compris dans ce texte sont : (i) Une généralisation de la conjecture de Hartshorne: une variété lisse projective est isomorphe à un espace projectif si et seulement si son fibré tangent contient un sous-faisceau ample.(ii) Stabilité du fibré tangent des variétés de Fano lisses de nombre de Picard un : à l'aide de théorèmes d'annulation sur les espaces hermitiens symétriques irréductibles de type compact M, nous montrons que pour presque toute intersection complète générale dans M, le fibré tangent est stable. La même méthode nous permet de donner une réponse sur la stabilité de la restriction du fibré tangent de l'intersection complète à une hypersurface générale.(iii) Non-annulation effective pour des variétés de Fano et ses applications : nous étudions la positivité de la seconde classe de Chern des variétés de Fano lisses de nombre de Picard un. Ceci nous permet de montrer un théorème de non-annulation pour les variétés de Fano lisses de dimension n et d'indice n-3. Comme application, nous étudions la géométrie anticanonique des variétés de Fano et nous calculons les constantes de Seshadri des diviseurs anticanoniques des variétés de Fano d'indice grand.(iv) Diviseurs fondamentaux des variétés de Moishezon lisses de dimension trois et de nombre de Picard un : nous montrons l'existence d'un diviseur lisse dans le système fondamental dans certain cas particulier
This thesis is devoted to the study of complex Fano varieties via the properties of subsheaves of the tangent bundle and the geometry of the fundamental divisor. The main results contained in this text are:(i) A generalization of Hartshorne's conjecture: a projective manifold is isomorphic to a projective space if and only if its tangent bundle contains an ample subsheaf.(ii) Stability of tangent bundles of Fano manifolds with Picard number one: by proving vanishing theorems on the irreducible Hermitian symmetric spaces of compact type M, we establish that the tangent bundles of almost all general complete intersections in M are stable. Moreover, the same method also gives an answer to the problem of stability of the restriction of the tangent bundle of a complete intersection on a general hypersurface.(iii) Effective non-vanishing for Fano varieties and its applications: we study the positivity of the second Chern class of Fano manifolds with Picard number one, this permits us to prove a non-vanishing result for n-dimensional Fano manifolds with index n-3. As an application, we study the anticanonical geometry of Fano varieties and calculate the Seshadri constants of anticanonical divisors of Fano manifolds with large index.(iv) Fundamental divisors of smooth Moishezon threefolds with Picard number one: we prove the existence of a smooth divisor in the fundamental linear system in some special cases

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May, Paul. "Improved sequential and batch learning in neural networks using the tangent plane algorithm." Thesis, University of Bolton, 2012. http://ubir.bolton.ac.uk/554/.

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The principal aim of this research is to investigate and develop improved sequential and batch learning algorithms based upon the tangent plane algorithm for artificial neural networks. A secondary aim is to apply the newly developed algorithms to multi-category cancer classification problems in the bio-informatics area, which involves the study of dna or protein sequences, macro-molecular structures, and gene expressions.

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Makki, Naciri Abderrahim. "Approximation par son cône tangent d'une partie définie par des égalités et des ingalités." Lille 1, 1994. http://www.theses.fr/1994LIL10197.

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Santos, Maria Inês Valente Pereira Trindade. "Evolution of tangent portfolios : an analysis of the european industries from 2000 to 2014." Master's thesis, Instituto Superior de Economia e Gestão, 2015. http://hdl.handle.net/10400.5/10704.

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Mestrado em Finanças
O objetivo do presente estudo é analisar o impacto de quatro grandes choques financeiros no mercado europeu de ações, por setor. Em particular, são analisadas as variações no ótimo de Markowitz (1952) de Carteiras Tangentes de Investidores Europeus. Estes são carteiras reais, sem erros de estimação. O período em análise é de 2000 a 2014, que compreende os seguintes choques financeiros: (i) 11 de Setembro, 2001; (ii) a crise Dot-Com, entre 2000 e 2001; (iii) a crise de hipotecas do sub-prime, entre 2007 e 2008; e (iv) a crise da dívida soberana europeia, durante 2011. Para o efeito, são utilizados como ativos subjacentes 16 índices de setores Europeus que incluem empresas de 16 países Europeus. A diminuição da diversificação em períodos de crise, embora mais suave para períodos de investimento mais curtos são alguns dos resultados desta investigação. No sentido de complementar a análise desenvolvida neste estudo, sugere-se que se componham Carteiras Tangentes reais através de índices de referência de países Europeus. Além disso, também se propõe uma extensão do período de tempo analisado, pelo menos até ao final de 2015, tendo em consideração os últimos desenvolvimentos em matéria de choques que têm afetado a Europa.
The aim of this study is to analyze the impact of four major financial shocks on European stock markets by sector. In particular, we analyze the variations in the optimal Markowitz (1952) Tangent Portfolios of European investors. These are real life portfolios, with no estimation errors. The period under analysis is from 2000 to 2014, which comprises the following shocks: (i) the 11th September, 2001; (ii) the Dot-Com crisis, during 2000-2001; (iii) the sub-prime mortgages crisis, during 2007-2008; and (iv) the European sovereign debt crisis, during 2011. We use 16 European sector indices as underlying assets, including companies from 16 European countries. Decreased diversification in crisis periods, although milder for shorter investment horizons are some of the findings of this investigation. Also, to complement the analysis carried out in this investigation, we suggest to compose real life Tangent Portfolios using reference indices of European countries. We also propose an extension of the data-range, at least until the end of 2015, given the latest developments regarding shocks affecting Europe.

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Cardoso, João Nuno Martins. "Robust mean variance." Master's thesis, Instituto Superior de Economia e Gestão, 2015. http://hdl.handle.net/10400.5/10706.

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Mestrado em Finanças
Este estudo empírico tem como objectivo avaliar o impacto da estimação robusta nos portefólios de média variância. Isto foi conseguido fazendo uma simulação do comportamento de 15 acções do SP500. Esta simulação inclui dois cenários: um com amostras que seguem uma distribuição normal e outro com amostras contaminadas não normais. Cada cenário inclui 200 reamostragens. O performance dos portefólios estimados usando a máxima verosimilhança (clássicos) e dos portefólios estimados de forma robusta são comparados, resultando em algumas conclusões: Em amostras normais, portefólios robustos são marginalmente menos eficientes que os portefólios clássicos. Contudo, em amostras não normais, os portefólios robustos apresentam um performance muito superior que os portefólios clássicos. Este acréscimo de performance está positivamente correlacionado com o nível de contaminação da amostra. Em suma, assumindo que os retornos financeiros têm uma distribuição não normal, podemos afirmar que os estimadores robustos resultam em portefólios de média variância mais estáveis.
This empirical study's objective is to evaluate the impact of robust estimation on mean variance portfolios. This was accomplished by doing a simulation on the behavior of 15 SP500 stocks. This simulation includes two scenarios: One with normally distributed samples and another with contaminated non-normal samples. Each scenario includes 200 resamples. The performance of maximum likelihood (classical) estimated portfolios and robustly estimated portfolios are compared, resulting in some conclusions: On normally distributed samples, robust portfolios are marginally less efficient than classical portfolios. However, on non-normal samples, robust portfolios present a much higher performance than classical portfolios. This increase in performance is positively correlated with the level of contamination present on the sample. In summary, assuming that financial returns do not present a normal distribution, we can state that robust estimators result in more stable mean variance portfolios.

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Khodabandehlou, Taraneh. "Application de la méthode du système simple tangent à l'étude du comportement viscoélastique du sang." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37598768j.

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32

Rammal, Jamal. "Capteurs microondes en bande ISM pour la caractérisation de matériaux en champ proche et pour le suivi de l’évolution de la corrosion." Thesis, Limoges, 2014. http://www.theses.fr/2014LIMO0049/document.

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Les travaux de thèse sont axés sur le développement de nouvelles techniques de caractérisation basées sur la variation de la réponse d’un résonateur, réponse modifiée par les propriétés diélectriques ou métalliques d’un matériau sous test. La première méthode utilise la microscopie microonde en champ proche pour la caractérisation résonante et non destructive de matériaux diélectriques dans la bande ISM (2,45 GHz).Celle-ci permet de déterminer les propriétés électromagnétiques (permittivité relative, tangente de pertes) des échantillons diélectriques solides de faible volumepar rapport à la longueur d’onde de mesure, et cela sans aucun traitement préalable. La connaissance de ces paramètres est essentielle pour fournir des informations critiques nécessaires pour la conception, la modélisation et la fabrication de circuits microondes. Une deuxième approche vise l’étude et le développement d’un nouveau capteur à base de céramique, économique, sensible, et pouvant s’intégrer dans un système sans fil pour la détection et la caractérisation du degré de corrosion. Ces nouveaux capteurs fournissent des informations sur l'état de l'équipement opérationnel d’une structure cible afin d'assurer la sécurité de cette dernière et par conséquent celle de leurs utilisateurs. Pour ces deux axes d’études, des simulations sur des logiciels de calcul électromagnétique ont été effectuées puis validées par des mesures expérimentales
This Ph. D thesis focuses on the development of new characterization techniques of dielectric and metallic materials in the ISM band (2.45 GHz). The first proposed method is based on non-destructive near field microave microscopy. This technique allows the determination of the electromagnetic properties (permittivity, loss tangent) of solid dielectric samples of small volume without prior treatment. The knowledge of these parameters is essential to provide critical information needed for accurately designing, modeling and manufacturing microwave circuits. A second study focuses on the development of a new, ceramic based, sensitive and economic sensor that can be integrated in a wireless system for the detection and characterization of the corrosion evolution. These new sensors provide information about the state of the operational equipment of the target structure in order to ensure the safety of these structures and therefore that of their users. In these two studies, simulations on electromagnetic calculation software have been performed and validated by experimental measurements

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Eddy, Scott M. "Lie Groups and Lie Algebras." Youngstown State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1320152161.

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Lima, Jessé Américo Gomes de. "Otimização em Meteorologia: cálculo de perturbações condicionais não-lineares ótimas." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/45/45134/tde-25052012-170217/.

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Neste trabalho estudamos as aplicações do método do Gradiente Espectral Projetado (SPG) em Meteorologia nos campos de previsibilidade, estabilidade e sensibilidade. Inicialmente revisamos os Vetores Singulares Lineares (LSVs) e em seguida apresentamos a teoria das Perturbações Condicionais Não-Lineares Ótimas (CNOPs). Enquanto os métodos clássicos estão baseados no Modelo Tangente Linear, as CNOPs são uma formulação do mesmo problema baseado em Programação Não-Linear. As CNOPs são descritas na literatura como responsáveis por melhorias em relação aos métodos anteriores. Finalmente analisamos três exemplos de aplicação do método à problemas de previsibilidade, estabilidade e sensibilidade.
A revision about applications of Spectral Projected Gradient (SPG) in meteorology is done in the fields of predictability, stability and sensitivity. Initially we review about Linear Singular Vectos (LSVs) and we present the Conditional Nonlinear Optimal perturbations (CNOPs). While the classic methods are based on the Tangent Linear Model, CNOPs are another formulation of the problem based on Nonlinear Programming. CNOPs are described in bibliography as responsible by better results than older methods. Finally we analyze three applications in predictability, stability and sensibility.

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Podkorytov, Sergey. "Espaces tangents pour les formes auto-similaires." Phd thesis, Université de Bourgogne, 2013. http://tel.archives-ouvertes.fr/tel-01005330.

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Nous nous intéressons à la modélisation de formes complexes de type structures arborescences, formes lacunaires ou surfaces rugueuses. Ces formes sont intéressantes de par leurs propriétés physiques particulières :objets légers, économie de matière, résistance mécanique, absorption acoustique importante. Les modèles basés sur le concept de la géométrie fractale permettent de générer de telles formes et notamment les formes auto-similaires. A partir des travaux de Barnsley sur les systèmes itérés de fonctions, Tosan et al, ont proposé une extension, Boundary Controled Iterated Funcions Systems (BCIFS) pour contrôler plus facilement les formes et faciliter leur description. Nous nous intéressons aux propriétés différentielles des formes décrites par BCIFS. Nous proposons une définition plus générale d'espace tangent qui permet de caractériser le comportement de cas non-classiquement différentiables.Nous montrons que l'étude du comportement différentiel peut alors se faire simplement par analyse des valeurs propres et vecteurs propres généralisés des opérateurs de subdivision. Il devient alors possible de contrôler ces propriétés différentielles. Nous présentons une application de nos résultats, en proposant une méthode pour construire des raccords entre deux structures définies par des processus de subdivision différents. Cette méthode est appliquée pour la construction d'un raccord entre une surface de subdivision de Doo-Sabin(schéma dual) et une surface de subdivision de Catmull-Clark (schéma primal)

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Lorrain, Jean-Paul Maurice Alfred. "Critère de ductilité basé sur la perte d'ellipticité du module tangent élastoplastique déduit d'un modèle autocohérent." Paris, ENSAM, 2005. https://pastel.archives-ouvertes.fr/pastel-00001207.

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Cette thèse a pour but de modéliser un critère de perte de ductilité. Pour cela, ce travail a été fait en trois étapes. Dans un premier temps, le comportement à l'échelle locale (qui est celle d'un grain ou d'un monocristal) est modélisé par une loi micromécanique écrite dans le cadre des grandes déformations. L'écrouissage étant quant à lui pris en compte par une matrice dont la variable interne est la densité de dislocations moyenne par système de glissement. Cette modélisation est apte à reproduire le comportement de monocristaux de ferrite ou d'alliage fer-silicium pour des trajets simples et complexes. Dans un deuxième temps la transition d'échelles entre le comportement local et celui d'un agrégat polycristallin est réalisée grâce au schéma autochérent au sens de Hill. A cette étape il es montré que la modélisation adoptée est capable de prédire le comportement pour des aciers monophasés, biphasés et monphasés contenant des précipités pour des trajets simples et complexes. De plus, le modèle donne aussi de bons résultats dans le calcul de coefficient de Lankford et des surfaces de charge ainsi que pour la prédiction de l'évolution des textures. La troisème étape consiste à introduire un critère de perte de ductilité basé sur la perte d'ellipticité du module tangent élastoplasique, c'est le critère de Rice. Ce critère est ensuite utilisé pour tracer des courbes limite de formage et il est montré que de bons résultats sont obtenus
The aim of this phd thesis is to model a ducitlity loss criterion. To do that, this work has been done in three steps. In a first time, the behavior at the local scale (which is the one of a grain or a single crystal) has been modeled by a micromechanical law written in the large strain framework. Hardening is, as for it, taken into acount by a matrix which internal variable is the mean dislocation density on a slip system. This modelisation is able tio reproduce the behavior of ferrite and iron-silicium single crystals for simple and complex loading paths. In a second time, the scale transition between the local behavior and the one of a polycrystalline aggregate is realized thanks to the self-consistent scheme at the sense of hill. It is shown that, at this step, the adopted model is able to predict the behavior for single-phase, dual-phase ferrite and martensite and single-phase with precipitates steels for simple and complex loading paths. In plus, this model gives also good results for calculus of lankford coefficient and yield surface and also for predicting texture evolution. The third step conists in the introduction of a ductility loss criterion based on the ellipticity loss of the elastic-plastic tangent modulus, this is rice's criterion. This criterion is used to plot forming limit diagrams and it is shown that good results can be given

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Sharma, Divya [Verfasser], and Michael [Akademischer Betreuer] Weiß. "Tangent spaces to the Teichmüller space from the energy-conscious perspective / Divya Sharma ; Betreuer: Michael Weiß." Münster : Universitäts- und Landesbibliothek Münster, 2021. http://d-nb.info/1240312415/34.

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38

Lindqvist, Stina, and Ida Lindstedt. "Från penna till tangent : En systematisk litteraturstudie om hur digitala verktyg påverkar elevers skrivande i grundskolan." Thesis, Linnéuniversitetet, Institutionen för svenska språket (SV), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-91124.

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I denna systematiska litteraturstudie ska tidigare forskning analyseras och presenteras. Syftet med studien är att belysa hur användningen av digitala verktyg påverkar elevers skrivande och deras skrivutveckling från förskoleklass till årskurs 6. Studiens frågeställningar handlar om hur digitala verktyg påverkar elevers skrivutveckling, kvalitén på elevers texter och elevers motivation att skiva. Materialet som ligger till grund för studien är 13 vetenskapliga publikationer, där fem är forskningsöversikter och åtta är empiriska studier. Majoriteten av forskningen utgår från den sociokulturella teorin, den kognitiva teorin och pragmatismen. Dessa publikationer har analyserats med en innehållsanalys och sedan kategoriserats in i olika scheman. Resultatet visar att digitala verktyg påverkar elevers skrivande såväl positivt som negativt. De positiva aspekter forskningen presenterar är bland annat att elever kan få stöttning av verktyget i form av olika program och applikationer. De påverkar även elevers motivation, och engagemanget till uppgiften blir större. Dock kan verktygens lekfulla funktioner bli ett störningsmoment. Andra negativa aspekter är att färre delar av hjärnan stimuleras och att elever inte utvecklar sin finmotorik i användningen av digitala verktyg. Många forskare presenterar även vikten av lärares digitala kompetens för att skapa en gynnsam undervisning. Forskningen är samstämd om att elever bör använda såväl penna och papper som digitala verktyg i sitt textskapande.

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39

Phuksuwan, Ouamporn. "On the primality conjecture for certain elliptic divisibility sequences." Thesis, University of East Anglia, 2009. https://ueaeprints.uea.ac.uk/10608/.

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This thesis is devoted to investigating some properties of the sequence (Wn) of the denominators. This is a divisibility sequence; that is, Wm | Wn whenever m | n. Our task here is to examine a conjecture on the number of prime terms in (Wn), well known as the Primality conjecture. We will prove that there is a uniform lower bound on n beyond such that all terms Wn have at least two distinct prime factors. In some cases, the bound is as low as n = 2.

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Brothers, Michael. "A comparison of different methods for calculating tangent-stifess matrices in a massively parallel computational peridynamics code." Thesis, The University of Texas at San Antonio, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1550324.

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In order to maintain the quadratic convergence properties of the first-order Newton's method in quasi-static nonlinear analysis of solid structures it is crucial to obtain accurate, algorithmically consistent tangent-stiffness matrices. For an extremely small class of nonlinear material models, these consistent tangent-stiffness operators can be derived analytically; however, most often in practice, they are found through numerical approximation of derivatives. A goal of the study de- scribed in this thesis was to establish the suitability of an under-explored method for computing tangent-stiffness operators, referred to here as 'complex-step'. Compared are four methods of nu- merical derivative calculation: automatic differentiation, complex-step, forward finite difference, and central finite difference in the context of tangent-stiffness matrix calculation in a massively parallel computational peridynamics code. The complex-step method was newly implemented in the peridynamics code for the purpose of this comparison. The methods were compared through in situ profiling of the code for Jacobian accuracy, solution accuracy, speed, efficiency, Newton's method convergence rate and parallel scalability. The performance data was intended to serve as practical guide for code developers and analysts faced with choosing which method best suit the needs of their application code. The results indicated that complex-step produces Jacobians very similar, as measured by a low l 2 norm of element wise difference, to automatic differentiation. The values for this accuracy metric computed for forward finite difference and central finite differ- ence indicated orders of magnitude worse Jacobian accuracy than complex-step, but convergence vstudy results showed that convergence rate and solution was not strongly affected. Ultimately it was speculated that further studies on the effect of Jacobian accuracy may better accompany experiments conducted on plastic material models or towards the evaluation of approximate and Quasi-Newton's methods.

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El, Boukharia Abderrahman. "Détermination explicite du cône tangent à une variété de niveau en un point singulier : application à l'optimisation." Lille 1, 1985. http://www.theses.fr/1985LIL10093.

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Soient E et F des espaces de Banach, U un ouvert de E et f une application de classe C(k), k >ou égal à 2, de U dans F. On donne une suite de conditions (Mn) n >ou égal à 1, de plus en plus faibles, relatives à une application bilinéaire symétrique continue, telles que, si en un point a de U la différentielle Df(a) est un morphisme direct et la différentielle seconde intrinsèque Delta²f(a) vérifie l'une des conditions (Mn), alors le cône tangent en a à la variété de niveau f passant par a est égal au cône isotrope de Delta²f(a). Cette détermination explicite du cône tangent est exploitée pour donner des conditions nécessaires d'optimalité pour un problème avec contraintes bilatérales vérifiant (Mn). On trouve dans tous les cas des conditions d'ordre 1; des conditions d'ordre 2 sont explicitées dans le cas (M(2)).

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Hoggard, John W. "Accuracy of Computer Generated Approximations to Julia Sets." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/28647.

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A Julia set for a complex function $f$ is the set of all points in the complex plane where the iterates of $f$ do not form a normal family. A picture of the Julia set for a function can be generated with a computer by coloring pixels (which we consider to be small squares) based on the behavior of the point at the center of each pixel. We consider the accuracy of computer generated pictures of Julia sets. Such a picture is said to be accurate if each colored pixel actually contains some point in the Julia set. We extend previous work to show that the pictures generated by an algorithm for the family $lambda e^z$ are accurate, for appropriate choices of parameters in the algorithm. We observe that the Julia set for meromorphic functions with polynomial Schwarzian derivative is the closure of those points which go to infinity under iteration, and use this as a basis for an algorithm to generate pictures for such functions. A pixel in our algorithm will be colored if the center point becomes larger than some specified bound upon iteration. We show that using our algorithm, the pictures of Julia sets generated for the family $lambda an(z)$ for positive real $lambda$ are also accurate. We conclude with a cautionary example of a Julia set whose picture will be inaccurate for some apparently reasonable choices of parameters, demonstrating that some care must be exercised in using such algorithms. In general, more information about the nature of the function may be needed.
Ph. D.

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Anel, Mathieu. "Champs de modules des catégories linéaires et abéliennes." Phd thesis, Université Paul Sabatier - Toulouse III, 2006. http://tel.archives-ouvertes.fr/tel-00085627.

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Les catégories linéaires ont naturellement plusieurs notions d'identification : l'isomorphie, l'équivalence de catégories et l'équivalence de Morita. On construit les champs classifiant les catégories pour ces trois structures ($\ukcatiso$, $\ukcateq$, $\ukcatmor$) ainsi que le champ classifiant les catégories abéliennes ($\ukab$), l'originalité étant que les trois derniers champs sont des champs supérieurs.

Le résultat principal de la thèse est que, sous des conditions de finitude des objets classifiés, ces champs sont géométriques au sens de C.~Simpson. En particulier, on trouve que les complexes tangents de ces champs en une catégorie $C$, i.e. les objets classifiant les déformations au premier ordre de $C$, sont donnés par des tronqués du complexe de cohomologie de Hochschild de $C$.

En plus, il existe une suite naturelle de morphismes surjectifs de champs :
$$\ukcatiso \tto \ukcateq \tto \ukcatmor \tto \ukab$$
dont on montre que celui du milieu est étale, et celui de droite une équivalence.

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Mickutė, Laura. "Apie trečios eilės liestinių sluoksniuočių geometriją." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2005. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2005~D_20050623_101559-72938.

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In this work is analysed the tangent bundle geometry order 3. Those bundles are defined like 3 - jet space. Co - ordinates transformation formulas of those bundles are received, how the object of linear connection inducted affine connections is demonstrated. In this work the theorem how the object of linear connection of tangent bundle inducted linear connection of tangent bundle order 3 is proved.

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Cruzado, Fábio Leandro. "Atividades práticas para o ensino do conceito de tangente no 9° ano." Universidade Federal de São Carlos, 2016. https://repositorio.ufscar.br/handle/ufscar/8266.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
We introduce some geometric experiments to the students, and particularly the handling of right-angled triangles, with the clear purpose of inserting, firming and emphasizing the importance, historical and practical, of the concept and meaning of the geometric tangent in an entire acute angle in triangle. Later, the students built a rudimentary theodolite that was used to measure vertical angles of tops inaccessible objects from the ground and consequently the estimate of their heights. The prospect objects were trees, poles, masts, antennas, spotlights, among other more familiar to the students of the ninth grade in elementary school.
Neste trabalho apresentamos aos alunos alguns experimentos geométricos e, sobretudo, a manipulação de triângulos retângulos, com o claro objetivo de inserir, fixar e ressaltar a importância, histórica e prática, do conceito e do significado geométrico da tangente de um ângulo agudo. Posteriormente, os alunos construíram um teodolito rudimentar que foi utilizado para medir ângulos verticais de topos de objetos inacessíveis em relação ao solo e consequentemente o cálculo de suas alturas. Os objetos explorados foram árvores, postes, mastros, antenas, refletores, entre outros mais familiares para os estudantes do nono ano do Ensino Fundamental.

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Ferreira, Daiane Gonçalves 1988. "Métodos de otimização de terceira ordem." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306029.

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Orientadores: Margarida Pinheiro Mello, Maria Aparecida Diniz Ehrhardt
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica
Made available in DSpace on 2018-08-22T15:49:27Z (GMT). No. of bitstreams: 1 Ferreira_DaianeGoncalves_M.pdf: 1441315 bytes, checksum: 1196d8b21c6254dbdd0e0d68266fa707 (MD5) Previous issue date: 2013
Resumo: Métodos de Otimização de terceira ordem, embora de longa tradição, eram considerados, até passado recente, impraticáveis, devido à taxa com que o esforço computacional cresce em função da dimensão do problema. Avanços no desenvolvimento de estruturas de dados, rotinas que trabalham com estas estruturas e a exploração da esparsidade de grande parte dos problemas encontrados na prática já permitem implementações destes métodos que podem torná-los competitivos com métodos de segunda ordem. O objeto desta dissertação é a apresentação do método de Halley, um método de terceira ordem, sua implementação em MATLAB e a realização de testes computacionais, visando uma comparação empírica de sua eficiência frente ao método de Newton, o método de segunda ordem mais empregado na atualidade
Abstract: Higher order optimization methods, though of long-standing tradition, until recently have been deemed impractical, due to the rate of increase of the computational effort as a function of the size of the problem. Advances in the development of data structures, routines that work with these structures and the use of the sparsity of a vast range of practical problems have led to implementations of these methods that are competitive with second order methods. The object of this dissertation is the study of Halley's method, a thirdorder method, the development of a MATLAB implementation thereof and its testing, aiming at an empirical comparison of its efficiency against that of Newton's method, the second-order method most widely used today
Mestrado
Matematica Aplicada
Mestra em Matemática Aplicada

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Martins, Rodrigo. "Singularidades das Superfícies Regradas em R3." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/55/55135/tde-18052004-174739/.

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Estudaremos as singularidades genéricas de superfécies regradas em R3. O objetivo do trabalho é mostrar que as singularidades genéricas que ocorrem no conjunto das superfícies regradas são as mesmas que ocorrem no conjunto das aplicações diferenciáveis de R2 em R3, enquanto que as singularidades genéricas das superfícies desenvolvíveis, que formam um subconjunto das superfícies regradas, são mais degeneradas.
We study generic singularities of ruled surfaces in R3. In this work we show that generic singularities appearing in the set of ruled surfaces are the same that occur in the set of map germs from R2 to R3, while the generic singularities of developable surfaces are more degenerate.

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48

Wang, Hongyuan. "On a class of algebraic surfaces with numerically effective cotangent bundles." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1154450131.

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49

D'Augustine, Anthony Frank. "MATLODE: A MATLAB ODE Solver and Sensitivity Analysis Toolbox." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/83081.

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Abstract:

Sensitivity analysis quantifies the effect that of perturbations of the model inputs have on the model's outputs. Some of the key insights gained using sensitivity analysis are to understand the robustness of the model with respect to perturbations, and to select the most important parameters for the model. MATLODE is a tool for sensitivity analysis of models described by ordinary differential equations (ODEs). MATLODE implements two distinct approaches for sensitivity analysis: direct (via the tangent linear model) and adjoint. Within each approach, four families of numerical methods are implemented, namely explicit Runge-Kutta, implicit Runge-Kutta, Rosenbrock, and single diagonally implicit Runge-Kutta. Each approach and family has its own strengths and weaknesses when applied to real world problems. MATLODE has a multitude of options that allows users to find the best approach for a wide range of initial value problems. In spite of the great importance of sensitivity analysis for models governed by differential equations, until this work there was no MATLAB ordinary differential equation sensitivity analysis toolbox publicly available. The two most popular sensitivity analysis packages, CVODES [8] and FATODE [10], are geared toward the high performance modeling space; however, no native MATLAB toolbox was available. MATLODE fills this need and offers sensitivity analysis capabilities in MATLAB, one of the most popular programming languages within scientific communities such as chemistry, biology, ecology, and oceanogra- phy. We expect that MATLODE will prove to be a useful tool for these communities to help facilitate their research and fill the gap between theory and practice.
Master of Science

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Halim-Dihardja, Marjammanda K. "Diagenesis and sedimentology of the late Devonian (Famennian) Wabamun group in the Tangent, Normandville, and Eaglesham fields, north-central Alberta." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63807.

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Dissertations / Theses on the topic 'Tangent'

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