La Ingeniería Geomática en la Antártida

El estudio de los frentes glaciares combina diferentes técnicas geomáticas de medida como el levantamiento clásico usando estación total o teodolito, técnicas GNSS (Global Navigation Satellite System), usando láser-escáner y mediante fotogrametría (aérea o terrestre). La medida por métodos directos (levantamiento clásico y GNSS) resulta útil y rápida cuando la accesibilidad a los frentes glaciares lo permite, mientras que es prácticamente imposible de realizar, en el caso de frentes glaciares que acaban en mar. En esta presentación, se estudia una metodología que combina los métodos fotogramétricos y otras técnicas para el levantamiento del frente del glaciar Johnsons, de difícil acceso. Las imágenes obtenidas del frente, provienen de una cámara digital no métrica; su georreferenciación a un sistema global de coordenadas se lleva a cabo midiendo puntos de apoyo por GNSS en las zonas laterales accesibles del frente glaciar y aplicando métodos de intersección directa en puntos inaccesibles de dicho frente, realizando medidas con teodolito. El resultado de las observaciones obtenidas se aplicará al estudio de la evolución temporal (1957-2014) de la posición del frente del glaciar Johnsons y de la posición de los frentes Argentina, Las Palmas y Sally Rocks del glaciar Hurd.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Integración de modelos numéricos de glaciares y procesado de datos de georradar en un sistema de información geográfica

Los modelos de termomecánica glaciar están definidos mediante sistemas de ecuaciones en derivadas parciales que establecen los principios básicos de conservación de masa, momento lineal y energía, acompañados por una ley constitutiva que define la relación entre las tensiones a las que está sometido el hielo glaciar y las deformaciones resultantes de las mismas. La resolución de estas ecuaciones requiere la definición precisa del dominio (la geometría del glaciar, obtenido a partir de medidas topográficas y de georradar), así como contar con un conjunto de condiciones de contorno, que se obtienen a partir de medidas de campo de las variables implicadas y que constituyen un conjunto de datos geoespaciales. El objetivo fundamental de esta tesis es desarrollar una serie de herramientas que nos permitan definir con precisión la geometría del glaciar y disponer de un conjunto adecuado de valores de las variables a utilizar como condiciones de contorno del problema. Para ello, en esta tesis se aborda la recopilación, la integración y el estudio de los datos geoespaciales existentes para la Península Hurd, en la Isla Livingston (Antártida), generados desde el año 1957 hasta la actualidad, en un sistema de información geográfica. Del correcto tratamiento y procesamiento de estos datos se obtienen otra serie de elementos que nos permiten realizar la simulación numérica del régimen termomecánico presente de los glaciares de Península Hurd, así como su evolución futura. Con este objetivo se desarrolla en primer lugar un inventario completo de datos geoespaciales y se realiza un procesado de los datos capturados en campo, para establecer un sistema de referencia común a todos ellos. Se unifican además todos los datos bajo un mismo formato estándar de almacenamiento e intercambio de información, generándose los metadatos correspondientes. Se desarrollan asimismo técnicas para la mejora de los procedimientos de captura y procesado de los datos, de forma que se minimicen los errores y se disponga de estimaciones fiables de los mismos. El hecho de que toda la información se integre en un sistema de información geográfica (una vez producida la normalización e inventariado de la misma) permite su consulta rápida y ágil por terceros. Además, hace posible efectuar sobre ella una serie de operaciones conducentes a la obtención de nuevas capas de información. El análisis de estos nuevos datos permite explicar el comportamiento pasado de los glaciares objeto de estudio y proporciona elementos esenciales para la simulación de su comportamiento futuro. ABSTRACT Glacier thermo-mechanical models are defined by systems of partial differential equations stating the basic principles of conservation of mass, momentum and energy, accompanied by a constitutive principle that defines the relationship between the stresses acting on the ice and the resulting deformations. The solution of these equations requires an accurate definition of the model domain (the geometry of the glacier, obtained from topographical and ground penetrating radar measurements), as well as a set of boundary conditions, which are obtained from measurements of the variables involved and define a set of geospatial data. The main objective of this thesis is to develop tools able to provide an accurate definition of the glacier geometry and getting a proper set of values for the variables to be used as boundary conditions of our problem. With the above aim, this thesis focuses on the collection, compilation and study of the geospatial data existing for the Hurd Peninsula on Livingston Island, Antarctica, generated since 1957 to present, into a geographic information system. The correct handling and processing of these data results on a new collection of elements that allow us to numerically model the present state and the future evolution of Hurd Peninsula glaciers. First, a complete inventory of geospatial data is developed and the captured data are processed, with the aim of establishing a reference system common to all collections of data. All data are stored under a common standard format, and the corresponding metadata are generated to facilitate the information exchange. We also develop techniques for the improvement of the procedures used for capturing and processing the data, such that the errors are minimized and better estimated. All information is integrated into a geographic information system (once produced the standardization and inventory of it). This allows easy and fast viewing and consulting of the data by third parties. Also, it is possible to carry out a series of operations leading to the production of new layers of information. The analysis of these new data allows to explain past glacier behavior, and provides essential elements for explaining its future evolution

Random samples generation with Stata from continuous and discrete distributions

Simulations are nowadays a very important way of analyzing new improvements in different areas before the physical implementation, which may require hard resources which could only be affronted in case of a high probability of success. The use of random samples from different distributions are a must in simulations. In this talk we introduce new Stata functions for generating random samples from continuous and discrete distributions that are not considered in the defined Stata random-number generation functions. In addition, we will also introduce new Stata functions for generating random samples as an alternative of the build-in Stata functions. The goodness of the generated samples will be checked using the mean squared error (MSE) of the differences between the frequencies of the sample and the theoretical expected ones. We will also provide bar charts which will allow the user to compare graphically the sample with the exact distribution function of the random distribution which is being sampled.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Teaching Partial Differential Equations with CAS

Partial Differential Equations (PDE) are one of the topics where Engineering students find more difficulties when facing Math subjects. A basic course in Partial Differential Equations (PDE) in Engineering, usually deals at least, with the following PDE problems: 1. Pfaff Differential Equations 2. Quasi-linear Partial Differential Equations 3. Using Lagrange-Charpit Method for finding a complete integral for a given general first order partial differential equation 4. Heat equation 5. Wave equation 6. Laplace’s equation In this talk we will describe how we introduce CAS in the teaching of PDE. The tasks developed combine the power of a CAS with the flexibility of programming with it. Specifically, we use the CAS DERIVE. The use of programming allows us to use DERIVE as a Pedagogical CAS (PECAS) in the sense that we do not only provide the final result of an exercise but also display all the intermediate steps which lead to find the solution of a problem. This way, the library developed in DERIVE serves as a tutorial showing, step by step, the way to face PDE exercises. In the process of solving PDE exercises, first-order Ordinary Differential Equations (ODE) are needed. The programs developed can be grouped within the following blocks: - First-order ODE: separable equations and equations reducible to them, homogeneous equations and equations reducible to them, exact differential equations and equations reducible to them (integrating factor technique), linear equations, the Bernoulli equation, the Riccati equation, First-order differential equations and nth degree in y’, Generic programs to solve first order differential equations. - First-order PDE: Pfaff Differential Equations, Quasi-linear PDE, Lagrange-Charpit Method for First-order PDE. - Second-order PDE: Heat Equation, Wave Equation, Laplace’s Equation. We will remark the conclusions obtained after using these techniques with our Engineering students.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Using extensions of the residue theorem for improper integrals computations with CAS

The computation of improper integrals of the rst kind (integrals on unbounded domain) are used in di erent applications in Engineering (for example in Kynetic Energy, electric potential, probability density functions, Gamma and Beta functions, Laplace and Fourier Transforms, Di erential Equations, . . . ). Nowadays, Computer Algebra Systems (CAS) are being used for developing such computations. But in many cases, some CAS lack of the appropriate rules for computing some of these improper integrals. In a previous talk in ESCO 2016 and a later extension, we introduced new rules for computing improper integrals of the rst kind using some results from Advanced Calculus Theories (Residue Theorem, Laplace and Fourier Transforms) aimed to improve CAS capabilities on this topic. In this talk, we develop new rules for computing other types of improper integrals using different applications from extended versions of the Residue Theorem. We will show some examples of such improper integrals that current CAS can not compute. Using extensions of the Residue Theorem in Complex Analysis, we will be able to develop new rules schemes for these improper integrals. These new rules will improve the capabilities of CAS, making them able to compute more improper integrals.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

LiDARgrammetry: A New Method for Generating Synthetic Stereoscopic Products from Digital Elevation Models

There are currently several new technologies being used to generate digital elevation models that do not use photogrammetric techniques. For example, LiDAR (Laser Imaging Detection and Ranging) and RADAR (RAdio Detection And Ranging) can generate 3D points and reflectivity information of the surface without using a photogrammetric approach. In the case of LiDAR, the intensity level indicates the amount of energy that the object reflects after a laser pulse is transmitted. This energy mainly depends on the material and the wavelength used by LiDAR. This intensity level can be used to generate a synthetic image colored by this attribute (intensity level), which can be viewed as a RGB (red, green and blue) picture. This work presents the outline of an innovative method, designed by the authors, to generate synthetic pictures from point clouds to use in classical photogrammetric software (digital restitution or stereoscopic vision). This is conducted using available additional information (for example, the intensity level of LiDAR). This allows mapping operators to view the LiDAR as if it were stereo-imagery, so they can manually digitize points, 3D lines, break lines, polygons and so on

SFOPDES: A stepwise tutorial for teaching Partial Differential Equations using a CAS

Partial Differential Equations (PDE) are one of the most difficult topics that Engineering and Sciences students have to study in the different Math subjects in their degree. In this talk we introduce SFOPDES (Stepwise First Order Partial Differential Equations Solver) aimed to be used as a tutorial for helping both the teacher and the students in the teaching and learning process of PDE. The type of problems that SFOPDES solves can be grouped in the following three blocks: 1. Pfaff Differential Equations, which consists on finding the general solution for: P(x; y; z) dx + Q(x; y; z) dy + R(x; y; z) dz = 0 (a) General method. (b) Particular cases: i. Separable equations. ii. Exact Pfaff equations. iii. One-separated variable equations. 2. Quasi-linear Partial Differential Equations, which consists on finding the general solution for: P(x; y; x) p + Q(x; y; z) q = R(x; y; z) (a) General method. (b) Particular solution which contents a given curve. 3. Using Lagrange-Charpit Method for finding a complete integral for a given general first order partial differential equation: F(x; y; z; p; q) = 0. (a) General method. (b) Particular cases: i. F(p; q) = 0 ii. g1(x; p) = g2(y; q) iii. z = px + qy + g(p; q)Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Improving CAS Capabilities: New Rules for Computing Improper Integrals

There are diferent applications in Engineering that require to compute improper integrals of the first kind (integrals defined on an unbounded domain) such as: the work required to move an object from the surface of the earth to in nity (Kynetic Energy), the electric potential created by a charged sphere, the probability density function or the cumulative distribution function in Probability Theory, the values of the Gamma Functions(wich useful to compute the Beta Function used to compute trigonometrical integrals), Laplace and Fourier Transforms (very useful, for example in Differential Equations).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

SPDES: A Stepwise Solver for Teaching Partial Differential Equations

Partial Differential Equations (PDE) are an important topic within the Engineering Degrees syllabus. In addition, many students find some dificulties in the learning process of this topic. Therefore, the use of didactical tools to improve the teaching and learning process of PDE is very helpful. In this talk, we introduce the solver SPDES (Stepwise Partial Differential Equation Solver), an extension of SFOPDES introduced in [1] where only first order PDE were considered. This new solver SPDES deals also with some second order PDE. It can be used as a self tutorial for PDE since it solves, step by step, the typical exercises within the topic. Specifically, the type of PDE that SPDES can solve are: 1. Pfaff Differential Equations. 2. Quasi-linear PDE. 3. Lagrange-Charpit Method for first order PDE. 4. Heat equation. 5. Wave equation. 6. Laplace's equation. where the fi rst three types where considered in SFOPDES and the last three types are new in SPDES. SPDES has been developed using the programming capabilities of a Computer Algebra System (CAS), displaying step by step the solution of the problem to be solved. This way, we potentiate the use of the CAS as a Pedagogical CAS (PeCAS). This fact makes SPDES to be an important tool for students which can use it as a tutorial for their learning process.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Advanced techniques to compute improper integrals using a CAS

Let us consider the following types of improper integrals: $$\int_0^\infty f(t)\:{\rm d}t \qquad ; \qquad \int_{-\infty}^0 f(t)\:{\rm d}t \qquad {\rm and} \qquad \int_{-\infty}^\infty f(t)\:{\rm d}t$$ \medskip Let $F$ be an antiderivative of $f$. The basic approach to compute such integrals involves the following computations: \medskip \begin{eqnarray*} \int_0^\infty f(t)\:{\rm d}t & = & \lim_{m\to\infty} \int_0^m f(t)\:{\rm d}t = \lim_{m\to\infty} \big(F(m)-F(0)\big) \\ \\ \int_{-\infty}^0 f(t)\:{\rm d}t & = & \lim_{m\to-\infty} \int_m^0 f(t)\:{\rm d}t = \lim_{m\to-\infty} \big(F(0)-F(m)\big) \\ \\ \int_{-\infty}^\infty f(t)\:{\rm d}t & = & \int_{-\infty}^0 f(t)\:{\rm d}t + \int_0^\infty f(t)\:{\rm d}t \qquad \mbox{or, in case of convergence,} \\ \\ \int_{-\infty}^\infty f(t)\:{\rm d}t & = & \lim_{m\to\infty} \int_{-m}^m f(t)\:{\rm d}t = \lim_{m\to\infty} \big(F(m)-F(-m)\big) \qquad \mbox{(Cauchy principal value)} \end{eqnarray*} \medskip \noindent But, what happens if an antiderivative $F$ for $f$ or the above limits do not exist? \medskip \noindent For example, for \quad $\displaystyle\int_0^\infty\frac{{\rm sin}(at)}{t}\:{\rm d}t$ \quad ; \quad $\displaystyle\int_0^\infty\frac{{\rm cos}(at)-{\rm cos}(bt)}{t}\:{\rm d}t$ \quad {\rm or} \quad $\displaystyle\int_{-\infty}^\infty\frac{{\rm cos}(at)}{t^2+1}\:{\rm d}t$ \qquad the antiderivatives can not be computed. Hence, the above procedures cannot be used for these examples. \medskip In this work we will deal with advance techniques to compute this kind of improper integrals using a {\sc Cas}. Laplace and Fourier transforms or Residue Theorem in Complex Analysis are some advance techniques which can be used for this matter. \medskip We will introduce the file \textbf{\tt ImproperIntegrals.mth}, developed in {\sc Derive} 6, which deals with such computations. \medskip Some {\sc Cas} use different rules for computing integrations. For example {\sc Rubi} system, a {\bf ru}le-{\bf b}ased {\bf i}ntegrator developed by Albert Rich (see {\tt http://www.apmaths.uwo.ca/\~{ }arich/}), is a very powerful system for computing integrals using rules. We will be able to develop new rules schemes for some improper integrals using {\tt ImproperIntegrals.mth}. These new rules can extend the types of improper integrals that a {\sc Cas} can compute.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech