MATHEMATICS (3)

Author: HERNÁNDEZ ABREU DOMINGO.
Year: 2005.
University: LA LAGUNA [More theses of this university] [www.ull.es].
Place of defense: FACULTAD DE MATEMATICAS.
Place of preparation: UNIVERSIDAD DE LA LAGUNA.

Summary: In this thesis is carrying out a numerical and theoretical treatment of various types of ordinary differential equations. After an introductory first chapter in which he gives readers an insight into the fundamentals that will be discussed in subsequent chapters, we study first the differential system with balances semiestables possessing a variety dimensional center. This is discussed in the second chapter of the memory unconditional stability of the methods and evidence that in practice the method of Euler implicit is the only one who has such a property. To regain stability for many kinds Runge-Kutta implicit methods, as well as methods of Rosenbrock, are considered in the third and fourth chapters integrations on temporary networks for the reasons sizes between consecutive steps are acostadas for some constant greater than one . Thus, in these chapters shows that A-estabilidad source of the methods is a sufficient condition for achieving integration in stable environments balances semiestables. In addition, numerical experiments conducted shows that the A-estabilidad strength of the General Linear methods applied to problems at intervals disipativos strictly temporary semi-infinitos. Specifically results are obtained from contractividad and convergence results generalize known for the classical methods of family type Runge-Kutta. This thesis concludes in the sixth chapter, which examines the conservation of invariants through methods Runge-Kutta explicit. Considering pairs explicit methods embedded strategy gives a projection methods type Runge-Kutta allowing retain invariants known for a differential system with a self-low cost, so the new technique can be considered in adaptive codes not affected the reliability and accuracy of the method basis.

Author: Fernández Delgado Isabel.
Year: 2005.
University: GRANADA [More theses of this university] [www.ugr.es].
Place of defense: Facultad de Ciencias.
Place of preparation: Facultad de Ciencias. Universidad de Granada.

Summary: This memory is dedicated to the areas with maximal singularities isolated in the space of Lorentz-Minkowski Dimension 3 and more generally in any 3-variedad Lorentziana complete and flat. Results are obtained on the behavior of these surfaces around the singularities, according structure and asymptotic behavior. Based on the existing Weierstrass representation for these areas, we take a theorem representacrón, which allows the construction of examples, and we get a formula linking the topology of the surface with the behavior of Weierstrass data and the number of singularities. Lastly, if we study the structure of embedded corresponding moduli space, demonstrating that it is a real analytic variety. There is a system of coordinates for this variety and considers the underlying topology.

Author: Lozano Palacio Antonio José.
Year: 2005.
University: SEVILLA [More theses of this university] [www.us.es].
Place of defense: Escuela Técnica Superior de Ingenieros.
Place of preparation: Escuela Técnica Superior de Ingenieros.

Summary: Two of the criteria used in the model attractive location, is the approach the center and the median. When the facility to locate brings unwanted effects were inverse problems of anticentro and antimediana. While the problems center / anticentro only takes into account the distance from the furthest point / P close of a set of n points in the criteria medium / antimediana is considered the sum of distances to all points of P. An intermediate approach is to consider the sum of distances from ak No points. Thus, to minimize the sum of distances to the most distant points k P leads to the problem of k-Centrum, while maximizing the sum of distances to the closest points k leads to the problem of Anti-k-Centrum. These criteria are individual cases to the center and anticentro, as well as the criteria and medium antimediana, and are in turn two cases for more general criteria: the criterion median and orderly approach antimediana sorted. However, the geometric properties underlying problems k-Centrum and Anti-k-Centrum allow more precise results and develop algorithms more efficient than those obtained by direct application of which are already known to the criteria and medium antimediana sorted . This memory is dedicated to studying the problems k-Centrum and Anti-k-Centrum in situations that have a combinatorial nature. Chapters 2 and 3 deal with the location, using the criterion Anti-k-Centrum, a punctual service in the plane and in a network. In both cases described a series dominant finite or, alternatively, are conditions that can find a solution, and develop algorithms to solve problems efficiently. In the case of timely location on the plane, using the criterion Anti-k-Centrum, evaluating the objective function in each candidate can be a very costly task. For this reason develop remarks on the objective function, which reduces the number of candidates that need to evaluate it. In both contexts explores the validity, when the points P are in no position overall, the results for the general case and describes the changes that must be made in the algorithms for solving various problems. Proposed alternatives and settled on issues such as distance used when the problem arose on the plane, or the location of users at the edges and the existence of edges directed, in the case of location networks. Chapter 4 is devoted to locating straight to the criteria k-Centrum and Anti-k-Centrum. In the first case there is a finite set dominant while the second provides conditions that allow finding a solution to the problem. It establishes strong characterizations, on the set of solutions, by imposing additional conditions on the problem data. Efficient algorithms are developed in both cases and explores the validity, when the points P are in position degenerate, the results obtained in the general case. It describes the changes in the algorithms necessary to solve the relevant problems, in the case degenerated, and proposes alternatives and decide on the objective function and the distance used. Moreover, the results are distinguished, for the problems k-Centrum and Anti-k-Centrum, where k = 1 or k = n which has enabled to establish the conditions to be met by a line antimediana and develop the corresponding algorithm. These results are especially important when one considers that, until now, for 8 issue of 318 the straight antimediana was the only classical problem of locating lines whose decision was unknown.

Author: BIADES CAPÓ ANTONIO.
Year: 2005.
University: ISLAS BALEARES [More theses of this university] [www.uib.es].
Place of defense: ESCULA POLITÉCNICA SUPERIOR.
Place of preparation: ESCUELA POLITÉCNICA SUPERIOR.

Summary: The main focus of this thesis is, first, define a mathematical method and an experimental methodology for comparing and classifying methods of eliminating noise in digital images. Secondly, we propose an algorithm (Non-Local means), capable of preserving the details of the image during the process of eliminating noise. Comparing all the details of the original image are preserved can be done by calculating the difference between the image and degraded version restored. This difference should not contain any structure or visible features and should resemble as closely as possible a noise. This difference is called "method noise" and has been mathematically and visually compared to the main methods of eliminating noise. We also propose to implement algorithms restoration pure noise. This new image should continue resembling a pure noise with a magnitude of the swings lower. Creating structure from noise means creating devices when the algorithm is applied to a real image. Second, we have proposed an algorithm (Non-Local means), fijandonos in the same image without making any assumptions about its regularity. This new algorithm replaces the value of a pixel by a weighted average of all the pixels of the image. Weights are oscillations and retains all the information as it is only an average delos similar pixels. Therefore, the NL-means used auto-similitudes of the image to reduce noise. The algorithm NL-means is particularly well suited to the image sequences. For a long time researchers in restoring video have restored each pixel along its path through the stream. This fact combined with static restoration of motion compensation. However, so far no one has managed to design an algorithm able to effectively trajectories of the objects. This is due to the ambiguity of trajectories. The NL-means need not calculate trajectories. Simply looking the more pixels that are similar no matter where they are. The experiment has demonstrated that it NL-means shows a greater ability to reduce noise at the same time is able to preserve more details and information of the original image that the major algorithms known.

Author: San José Nieto Luis Augusto.
Year: 2006.
University: VALLADOLID [More theses of this university] [www.uva.es].
Place of defense: Facultad de Ciencias.
Place of preparation: Facultad de Ciencias.

Summary: The Theory Inventory is one of the branches of the Operations Research that more scientific work has generated over the years. The reason is the significant benefits that the model can produce inventory management in the business. This work focuses on the development of new models deterministic inventory allowed the shortage or rupture stock. The thesis is organized as follows. In Chapter 1 presents six models EOQ (Economic Order Quantity) with extreme situations of scarcity (and cumulative demand completely lost sales) and quantitative discounts in the purchase price (discounts on all units and incremental discount). It identifies the best policies for each of these six models and perform various extensions of the findings to other situations, most notably the case known as composite lot size model. In Chapter 2 discusses inventory systems with ruptured where the fraction of cumulative demand is described by a function that depends only time a client should or should wait until the arrival of the next order. It develops a comprehensive approach to solve the optimization problem raised. It identifies policies efficient inventory for various functions and impatience is a sensitivity analysis with respect to several of the parameters considered. Finally, in Chapter 3 introduces a new conceptual perspective to model the behavior of customers address the shortage. Three new models are developed based on this perspective and proposes explicit algorithms to find the best policies for.

Author: Donoso Salgado Sergio.
Year: 2006.
University: GRANADA [More theses of this university] [www.ugr.es].
Place of defense: Univ. Tecno. Metropo. Santiago de Chile.
Place of preparation: Universidad de Granada, Universidad Tecnologica Metropolitana, Santiago de.

Summary: THE REGRESION DIFFUSE ALLOWED TO ESTABLISH RELATIONS BETWEEN AND VARIABLES PRECISAS

Author: MERILLAS SANTOS IVAN.
Year: 2006.
University: POLITÉCNICA DE CATALUÑA [More theses of this university] [www.upc.edu].
Place of defense: SALA PI I CALLEJA DE L'ETSAB.
Place of preparation: U FACULTAT DE MATEMATIQUES I ESTADISTICA SUD.

Summary: This thesis is concerned with the modeling and numerical study of nonsmooth dynamical systems (NSDS). The first part of the thesis deals with the modeling of some DC-DC power converters using the complementarity formalism. This mathematical theoretical framework allows us to ensure existence and uniqueness of solutions in a ânatural' and synthetic way. Specifically, it works pretty well in power electronic converters because it incorporates generalized discontinuous conduction modes (GDCM), characterized by a reduction of the dimension of the effective dynamics. For systems with a single diode, analytical state-space conditions for the presence of a GDCM are stated and simulation results, showing a variety of behaviours, such as persistent or re-entering GDCM, are also presented. Furthermore, the analysis and simulation of a parallel resonant converter (PRC), which has four diodes, illustrate the convenience of the complementarity formalism to simulate electrical systems with a large number of ideal diodes. We also present the simulation of a boost converter with a sliding mode control, even though a general control theory for complementarity systems is not still developed. In the second part of the thesis we focus on the bifurcation analysis in NSDS, and in particular, we have studied different mechanical systems which involve impacts and dry-friction. It is known that nonsmooth or discontinuous dynamical systems can exhibit the bifurcations also exhibited by smooth systems. In addition to these, there are also some novel transitions so-called discontinuity-induced bifurcations (DIBs) which are unique to these systems. We have investigated the complex behaviour occurring in an impacting mechanical system. DIBs such as corner impact bifurcations and transitions from complete to uncomplete chattering motions have been analysed in detail. Another type of DIBs recently classified are the so-called sliding bifurcations. Such bifurcations are a characteristic feature of so-called Filippov systems. We present detailed examples of all the different sliding bifurcation scenarios in a dry friction oscillator using a measured friction characteristic firstly introduced by Popp. Furthermore, a codimension-two degenerate switching-sliding bifurcation is displayed. In this case of degenerate switching-sliding bifurcation two curves of codimension-one sliding bifurcations, crossing-sliding and adding-sliding, branch out from the codimension-two point. Also, a cusp smooth codimension-two bifurcation is shown and coexistence of periodic orbits in the region between both fold codimension-one curves is studied. We have also investigated the dynamic behaviour of the two-block Burridge model for earthquake simulations. Previous numerical studies investigated by Ruina verified that, with a friction force of Coulomb type, the system presents only periodic behaviour. We show that chaotic regions can be observed in a symmetric configuration even if a Coulomb friction is considered with the relaxation of one of the assumptions assumed in the seismological literature. Furthermore, we have studied the behaviour of the system with asymmetric configuration. Different periodic solutions and regions of chaos can be observed varying the asymmetry of the system. With respect to the bifurcation point of view, we have analysed several smooth bifurcations (smooth and DIBs) observed in this system. Chapter 6 of this thesis presents the SICONOS software platform dedicated to simulation of NSDS. We give an overview of the SICONOS software and the way NSDS are modeled and simulated within the platform. Routines for analysis (stability, bifurcations, invariant manifolds,â¦) of NSDS implemented in the platform are explained in detail. To conclude this part, several representative samples are shown in order to illustrate the SI 8 CONOS pl 2de atform abilities. Conclusion and some open problems are presented in the last chapter.

Author: MARIA CINTA CABALLER VIVES.
Year: 2006.
University: PAÍS VASCO [More theses of this university] [www.ehu.es].
Place of defense: FACULTAD DE CIENCIA Y TECNOLOGÍA.
Place of preparation: FACULTAD DE CIENCIA Y TECNOLOGÍA.

Summary: In this dissertation shows knowledge of algebra which were transmitted to the students in the secondary school in Spain in the nineteenth century and the first third of the twentieth century. In addition, as it has developed this work, it has been possible to identify a large number of community members mathematical Spanish responsible for the transmission of that knowledge. The core of the memory is divided into seven chapters. The first gives an overview of the development of algebra over the nineteenth century and early decades of the twentieth century, giving news of some eminent mathematicians who participated in the process. Once exposed progress in algebra, interested in knowing how it occurred in Spain incorporating them. That is the subject of the second chapter. Focusing on the theme secondary education in the third chapter deals with the study of the institutes are designed as educational establishments under which should provide secondary education. In one of the paragraphs of this chapter shows the scientific biographies three instituís, emphasizing lessons in mathematics and the faculty responsible for them. The fourth chapter examines the contents of the course of algebra in secondary education through a range of programs and textbooks. The institute professors, authors of these programs and algebra textbooks, getting the job stability through contests movement and the opposition. In the fifth chapter files are reviewed several of these competitions, outlining in all cases the presence of algebra over the same. Since the Act Moyano obtaining a professorship in property accounted for admission to the roster of professors institute. An examination of several echelons which identify a good number of members of the mathematical community Spanish, shown in the sixth chapter. While in the preceding chapters, is giving news of a good number of professors of Mathematics, in the seventh chapter, on the one hand, sets out in detail the biographies académico-científicas seventeen professors, authors of textbooks algebra. Furthermore, it has produced a table of 321 entries that reflect aspects of the subject of this report, not covered in the previous chapters. The core of the report draws conclusions that culminate with the task of inquiry. The report is supplemented with four appendices. In the first two sets out a catalog of works of math (including algebra) collected over the drafting of this report, published in the nineteenth century and much of the twentieth century. In the following two are reproduced indexes programs and textbooks algebra studied in the fourth chapter.

Author: REDONDO LOPEZ JOSE MANUEL.
Year: 2006.
University: OVIEDO [More theses of this university] [www.uniovi.es].
Place of defense: E.U. INGENIERIA TECNICA INFORMATICA.
Place of preparation: DEPARTAMENTO DE INFORMATICA.

Summary: Dynamic languages such as Python or Ruby, usually run on a virtual machine implemented as an interpreter, taking advantage of the benefits they offer. This, together with the largest number of operations to be performed during the execution, which involves the performance of applications made with these lenjuajes is lower than that offered by the static languages. There are techniques that improve the performance of the aplicacones that run on virtual machines, such as the compilation Justo a Tiempo (Just in Time, JIT), allowing use these platforms for the development of commercial systems. This thesis used the same principle described to optimize dynamic languages. Based on a virtual machine with professional JIT compilation set modifications to their computational model to incorporate the characteristics of reflection offered by the structural dynamic languages, evaluating the performance gains at runtime. It will try to provide an efficient and integrated support for these features for the machine, so that we can use it to implement and support dynamic languages on the mass, improving their performance at runtime regard to other existing implementations. Compatibility with the code will remain fully inherited. For that reason, designing a new model that adds to the computational model based on object-oriented classes machine game, another model that uses principles of object oriented model based on prototypes. Additionally, we design a set of primitives to support the structural characteristics of reflection offered by the dynamic languages. These primitives are implemented in an integrated manner in its structure, making these new capabilities are part of the core functionality offered by the system extended. Change is also the semantics of some intermediate language instructions of the virtual machine, so that the JIT compiler can process according to the new model. Any language is translated directly to a common intermediate language, which would interact with dynamic and static languages. Finally, he examines both the profit performance at runtime and memory usage compared to other systems in dynamic scenarios representative, as well as the cost of providing greater flexibility to the static machine, and validating the theory of departure.

Author: HERRANZ CUADRADO MARIA VICTORIA.
Year: 2006.
University: MIGUEL HERNÁNDEZ DE ELCHE [More theses of this university] [www.umh.es].
Place of defense: CENTRO DE INVESTIGACION OPERATIVA.
Place of preparation: CENTRO DE INVESTIGACION OPERATIVA.

Summary: The objective of this report is the construction of convolutional codes through techniques drilled and networking. The technique applies drilled for the purpose of making powerful codes so that the Viterbi decoding is simplified considerably. In this work, as well as providing the classification of convolutional codes based on the construction of Justesen in terms of ownership MDS, new codes are obtained by applying the previous drilling, using the description of the code through its parent generation. The rest of the work is focused primarily in the construction, from the point of view of systems, new codes from the concatenation of others. While many authors have proposed building codes concatenation, they have not been studied using the theory of control. Furthermore, in this report we are working on finite bodies arbitrary, unlike most buildings concatenated codes, which are based on binary bodies. Over memory, the effects are conditions for obtaining representations entrada-estado-salida minimales different models cascading series of convolutional codes on a Galois arbitrary body, which knows the value of the complexity of the code and therefore, we can compare the distance free of these codes with the bound Singleton widespread. In addition, under certain conditions, which are modeled concatenated codes are not catastrophic. It was also shown that certain concatenations have free distance exceeding that of the constituent codes. This represents an important step forward because some codes constructed from concatenated codes whose distance is far from the peak Singleton, codes are found to be optimal, and therefore with a great capacity for error correction. After modeling different concatenations serial convolutional codes, drop to the characterization of the concatenation of a code block and a code convolucional used, for example, in consolidation channel in GSM technology. It analyzes representations entrada-estado-salida of different models, from the representations of the codes constituents. Also provides conditions for obtaining a code convolucional not catastrophic, based on a minimal representation. It also shows that networking can lead to convolutional codes heavily MDS under certain conditions, although concatenen a code block is not MDS and a code convolucional not MDS. It concludes by modeling different types of networking in parallel convolutional codes, providing conditions for the representations and minimales so that the codes are concatenated not catastrophic. It also discusses the properties of the different models, comparing them with each other. The fact working convolutional codes within modules yields intrinsic properties of the code rather than the parent generation, giving it shape tools to learn the complexity of the code, as well as to obtain codes not catastrophic with representations minimales whose distance free below is limited both as superiorly. In addition, linkages can be combined in series and in parallel concatenations of convolutional codes, both studied separately at work. This is a step prior to the implementation of these codes (as concatenated codes seek to achieve the highest rates of transmission possible from the Theory Shannon), as well as the introduction of efficient decoding algorithms that exploit the properties of algebraic these codes.

Author: Fernández Ascariz Pablo.
Year: 2006.
University: SANTIAGO DE COMPOSTELA [More theses of this university] [www.usc.es].
Place of defense: Facultad de Matemáticas.
Place of preparation: Facultad de Matemáticas de la Universidad de Santiago de Compostela.

Summary: This thesis examines the status of modules Crusaders commutative algebra, which generalizes simultaneously two different structures, and commutative algebra module. The first chapter gives the basics and built some limits. Furthermore, it was shown several properties in the category, for example, evidence that is semiabeliana and also that there is tripleable (basic fact in order to build a theory of (co) homology), ie there is a adjunción between modules Crusaders and September . It then examines in depth the unbalanced nature of the category and provides several definitions equivalent to the module crossover, which will be useful for later able to more easily manage various concepts. In the second chapter defines several buildings associated with the category: actor crossfire of a module, module cross unique switch, the tensor product, the product semidirecto, the category (C, R, f) -módulos and derivations. In addition, we study the properties of these objects, linking with each other and with their analogues in the category of commutative algebra. In the third chapter develops a theory of (co) homology blocks Crusaders, and discusses their properties getting some results of interest. It also addresses extensions modules Crusaders, they relate to cohomología defined and there are two successions on the exact differential. Finally, it identifies the (co) homology Crusaders certain modules, the modules Crusaders aspherical, with a particular class of (co) homology on algebra. The final chapter makes calculations troops homology groups nilpotentes free through its associated Lie algebra. It is noted that this method is faster and less demanding with respect to the computational resources that are needed, which so far has been in use, calculating this homology directly through a resolution of the group. This will get some homologías estimate that had not been computed so far. To make these calculations is used GAP (Groups, Algorithms, Programming), a system-oriented computer algebra and discreet are scheduled several functions that are included in one of his packages, PAHs (Homological Algebra Programming).

Author: Mosquera Rodríguez Manuel Alfredo.
Year: 2006.
University: SANTIAGO DE COMPOSTELA [More theses of this university] [www.usc.es].
Place of defense: Facultad de Matemáticas.
Place of preparation: Facultad de Matemáticas.

Summary: This thesis is divided into two distinct parts. The first of these is devoted to the study of three models of cooperative games with transferable utility arising from two operations research problems. The first model is the inventory of the games, where a rule is characterized splitting using a property immunity to manipulation through coalitions. The other two models are two new models: Plays and Plays Highway sequencing online proportional; these models are analyzed in depth. The second part is devoted to an analysis of the behavior problems cautious decision. We studied and characterized the behavior maximin and protective.

Author: SUÁREZ DE LA FUENTE JESÚS.
Year: 2006.
University: EXTREMADURA [More theses of this university] [www.unex.es].
Place of defense: UNIVERSIDAD DE EXTREMADURA.
Place of preparation: FACULTAD DE CIENCIAS, UNIVERSIDAD DE EXTREMADURA.

Author: Valero i Bayà Jordi.
Year: 2006.
University: AUTÓNOMA DE BARCELONA [More theses of this university] [www.uab.es].
Place of defense: Departament de Matemàtiques.
Place of preparation: Facultat de Ciències.

Summary: The thesis is compendium of the following articles: Puig, P. And Valero, J. (2006). Count data distributions: some characterizations with applications. J. Amer. Statist. Assoc., 101, 332 -- 340. Puig, P. And Valero, J. (2007). Characterization of count data distributions involving additivity and Binomial subsampling. Bernoulli, 13 (2), 544 -- 555. Both models are characterized distributions recount that meet certain conditions as to be closed by the addition or that the sample average is the maximum likelihood estimator of hope, or others which are defined in these articles. In the article "Count data distributions: some characterizations with applications," characterize all models biparamétricos distributions counting (met some very general technical conditions) that are partially covered by the addition. There are also those for which the maximum likelihood estimator of the average population is the sample average. Likewise, some are completely mixed Poisson models that meet these properties. Among these models are the Binomial negative Poisson-inversa Gaussiana and others who are also trained by known distributions. You can also build new distributions using the techniques employed in these characterizations. We show three examples of applications of the theoretical results of this work. In the article "Characterization of count data distributions involving additivity and Binomial subsampling," characterize all families r-paramétricas distributions count (under certain technical conditions very generic), which are closed by adding and Binomial subsampling. Surprisingly, there are few families that meet both conditions, and families are resulting in the univariate models of Hermite order r. Among these are the Poisson (r = 1) and Hermite normal distributions (r = 2). Also, as a secondary outcome, but no less important, are widespread results Wiuf, C. And Stumpf, MPH (2006) (Binomial subsampling. Proc. R. Soc. A 462, 1181 -- 1195), which characterize the functions generating probability distributions counting closed under Binomial subsampling.