Guia de desarrollo de Android por Anaya

Guia de desarrollo de Android por Anaya: "

En Enero, la editorial Anaya ha lanzado al mercado un libro de desarrollo para Android.

Sinopsis

La aparición de teléfonos móviles equipados con Android ha acelerado el interés y la demanda de esta plataforma. Además de trabajar con la creación y recepción de llamadas telefónicas, la recepción de mensajes SMS, o la forma de gestionar y definir alarmas, el uso de Android permite el manejo de bibliotecas OpenGL ES para crear sofisticados gráficos 2D y 3D. Este manual le proporcionará los conocimientos necesarios sobre la plataforma Android, incluida la arquitectura y configuración del entorno de desarrollo. Analizará los principales componentes de la interfaz gráfica, como View y Layout, así como la reproducción de elementos multimedia y el uso de la cámara y el micrófono para grabar archivos.

Las partes del libros constan de:

Parte I: Fundamentos

Parte II: El entorno de programación

Parte III: Combinar todas las piezas

Parte IV: Apéndices

Convenciones

Código fuente

Requisitos de software

El coste del libro es de 33,80 euros, estando disponible para su compra, en el siguiente link

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Graph realizations associated with minimizing the maximum eigenvalue of the Laplacian

Graph realizations associated with minimizing the maximum eigenvalue of the Laplacian: "

Abstract

In analogy to the absolute algebraic connectivity of Fiedler, we study the problem of minimizing the maximum eigenvalue of
the Laplacian of a graph by redistributing the edge weights. Via semidefinite duality this leads to a graph realization problem
in which nodes should be placed as close as possible to the origin while adjacent nodes must keep a distance of at least one.
We prove three main results for a slightly generalized form of this embedding problem. First, given a set of vertices partitioning
the graph into several or just one part, the barycenter of each part is embedded on the same side of the affine hull of the
set as the origin. Second, there is an optimal realization of dimension at most the tree-width of the graph plus one and this
bound is best possible in general. Finally, bipartite graphs possess a one dimensional optimal embedding.

• Content Type Journal Article
• Category Full Length Paper
• DOI 10.1007/s10107-010-0344-z
• Authors
  
  
  • Frank Göring, Technische Universität Chemnitz Fakultät für Mathematik 09107 Chemnitz Germany
  • Christoph Helmberg, Technische Universität Chemnitz Fakultät für Mathematik 09107 Chemnitz Germany
  • Susanna Reiss, Technische Universität Chemnitz Fakultät für Mathematik 09107 Chemnitz Germany
  
  

• Journal Mathematical Programming
• Online ISSN 1436-4646
• Print ISSN 0025-5610

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Randomized Kaczmarz solver for noisy linear systems

Randomized Kaczmarz solver for noisy linear systems: "

Abstract

The Kaczmarz method is an iterative algorithm for solving systems of linear equations Ax=b. Theoretical convergence rates for this algorithm were largely unknown until recently when work was done on a randomized
version of the algorithm. It was proved that for overdetermined systems, the randomized Kaczmarz method converges with expected
exponential rate, independent of the number of equations in the system. Here we analyze the case where the system Ax=b is corrupted by noise, so we consider the system Ax≈b+r where r is an arbitrary error vector. We prove that in this noisy version, the randomized method reaches an error threshold dependent
on the matrix A with the same rate as in the error-free case. We provide examples showing our results are sharp in the general context.

• Content Type Journal Article
• DOI 10.1007/s10543-010-0265-5
• Authors
  
  
  • Deanna Needell, Stanford University Department of Statistics Stanford CA 94305-4065 USA
  
  

• Journal BIT Numerical Mathematics
• Online ISSN 1572-9125
• Print ISSN 0006-3835

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Fast transforms for high order boundary conditions in deconvolution problems

Fast transforms for high order boundary conditions in deconvolution problems: "

Abstract

We study strategies to increase the precision in deconvolution models, while maintaining the complexity of the related numerical
linear algebra procedures (matrix-vector product, linear system solution, computation of eigenvalues, etc.) of the same order
of the celebrated fast Fourier transform. The key idea is the choice of a suitable functional basis to represent signals and
images. Starting from an analysis of the spectral decomposition of blurring matrices associated to the antireflective boundary
conditions introduced in Serra Capizzano (SIAM J. Sci. Comput. 25(3):1307–1325, 2003), we extend the model for preserving polynomials of higher degree and fast computations also in the nonsymmetric case.

We apply the proposed model to Tikhonov regularization with smoothing norms and the generalized cross validation in order
to choose the regularization parameter. A selection of numerical experiments shows the effectiveness of the proposed techniques.

• Content Type Journal Article
• DOI 10.1007/s10543-010-0266-4
• Authors
  
  
  • Marco Donatelli, Università dell’Insubria Dipartimento di Fisica e Matematica Via Valleggio 11 22100 Como Italy
  
  

• Journal BIT Numerical Mathematics
• Online ISSN 1572-9125
• Print ISSN 0006-3835

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Adaptive mesh refinement applied to the scalar transported PDF equation in a turbulent jet

Adaptive mesh refinement applied to the scalar transported PDF equation in a turbulent jet: "This paper describes a novel solution method for the transported probability density function (PDF) equation for scalars (compositions). In contrast to conventional solution methods based on the Monte Carlo approach, we use a finite-volume method combined with adaptive mesh refinement (AMR) applied in both physical and compositional space. The obvious advantage of this over a uniform grid is that fine meshes are only used where the solution requires high resolution. The efficiency of the method is demonstrated by a number of tests involving a turbulent jet flow with up to two scalars (both reacting and non-reacting). We find that the AMR calculation can be at a fraction of the computer cost of a uniform grid calculation with the same accuracy. Copyright © 2010 John Wiley & Sons, Ltd."

The Leaning Tower(s) of Pisa

The Leaning Tower(s) of Pisa: "

You may be familiar with the story behind the famous Tower of Hanoi puzzle, as related by Henri de Parville in 1884:

In the great temple at Benares beneath the dome which marks the centre of the world, rests a brass plate in which are fixed three diamond needles, each a cubit high and as thick as the body of a bee. On one of these needles, at the creation, God placed sixty-four discs of pure gold, the largest disc resting on the brass plate, and the others getting smaller and smaller up to the top one. This is the Tower of Bramah. Day and night unceasingly the priests transfer the discs from one diamond needle to another according to the fixed and immutable laws of Bramah, which require that the priest on duty must not move more than one disc at a time and that he must place this disc on a needle so that there is no smaller disc below it. When the sixty-four discs shall have been thus transferred from the needle on which at the creation God placed them to one of the other needles, tower, temple, and Brahmins alike will crumble into dust, and with a thunderclap the world will vanish.

A less familiar chapter in the temple's history is its brief relocation to Pisa in the early 13th century. The relocation was organized by the wealthy merchant-mathematician Leonardo Fibonacci, at the request of the Holy Roman Emperor Frederick II, who had heard reports of the temple from soldiers returning from the Crusades. The Towers of Pisa and their attendant monks became famous, helping to establish Pisa as a dominant trading center on the Italian peninsula.

Unfortunately, almost as soon as the temple was moved to Pisa, one of the diamond needles began to lean to one side. To avoid the possibility of the leaning tower falling over from too much use, Fibonacci convinced the priests to adopt a more relaxed rule: Any number of disks on the leaning needle can be moved together to another needle in a single move. It was still forbidden to place a larger disk on top of a smaller disk, and disks had to be moved one at a time onto the leaning needle or between the two vertical needles.

Thanks to Fibonacci's new rule, the priests could bring about the end of the universe somewhat more quickly from Pisa then they could than could from Benares. Fortunately, the temple was moved from Pisa back to Benares after the newly crowned Pope Gregory IX excommunicated Frederick II, making the local priests less sympathetic to hosting foreign heretics with strange mathematical habits. Soon afterward, a bell tower was erected on the spot where the temple once stood; it too began to lean almost immediately.

Describe an algorithm to transfer a stack of n disks from one vertical needle to the other vertical needle, using the smallest possible number of moves. Exactly how many moves does your algorithm perform, as a function of n?

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A Statistical Framework for Hierarchical Methods in Molecular Simulation and Design

A Statistical Framework for Hierarchical Methods in Molecular Simulation and Design: "Journal of Chemical Theory and Computation, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable)."

Stopping Criteria for Anisotropic PDEs in Image Processing

Stopping Criteria for Anisotropic PDEs in Image Processing: "

Abstract

A number of nonlinear diffusion-like equations have been proposed for filtering noise, removing blurring and other applications.
These equations are usually developed as time independent equations. An artificial time is introduced to change these equations
to parabolic type equations which are then marched to a steady state. In practice the time iteration is stopped before the
steady state is reached. The time when to stop the iteration is usually determined manually for each case. In this study we
develop a more automatic procedure for stopping the time integration.

• Content Type Journal Article
• DOI 10.1007/s10915-010-9361-6
• Authors
  
  
  • A. Ilyevsky, Tel-Aviv University Department of Mathematics Tel-Aviv Israel
  • E. Turkel, Tel-Aviv University Department of Mathematics Tel-Aviv Israel
  
  

• Journal Journal of Scientific Computing
• Online ISSN 1573-7691
• Print ISSN 0885-7474

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Colisiones múltiples en el LHC del CERN o los algoritmos de reconstrucción de trayectorias

Colisiones múltiples en el LHC del CERN o los algoritmos de reconstrucción de trayectorias: "

Preciosa imagen de una colisión doble (con dos vértices primarios) observada en el experimento ATLAS del LHC del CERN el 30 de marzo de 2010. En el LHC a 7 TeV la mayoría de las veces en el punto de colisión de dos “paquetes” (bunches) de protones se produce una colisión con múltiples vértices primarios (a 14 TeV se esperan hasta 24, con un más de 3500 partículas involucradas). En la figura, una colisión doble, dos protones de un paquete chocan simultáneamente con dos protones del paquete que incide en dirección opuesta. Una colisión típica, ver más abajo, contiene un vértice primario (que produce varios vértices secundarios), que corresponde a la colisión protón-protón más energética, y varios vértices primarios adicionales de poca energía (llamados vértices pile up, porque producen señales en los calorímetros que se apilan sobre las del vértice primario). Los algoritmos de seguimiento de trayectorias están preparados para discernir todas las trayectorias con precisión separando el grano (el vértice primario más energético) de la paja (resto de los vértices). En la figura de arriba, no me he molestado en contarlas, habrá unas 64 trayectorias de partículas. Imagina, por un momento, que hubiera 512 o 1024 trayectorias. Obviamente, lo más difícil para los algoritmos de detección de vértices y seguimiento de trayectorias son las colisiones con múltiples vértices primarios. En mi opinión, esta figura ilustra a la perfección que los algoritmos de análisis de trayectorias de ATLAS están funcionando de forma excelente. Los interesados en más detalles técnicos sobre estos algoritmos (implementados en C++ utilizando programación orientada a objetos) disfrutarán con E. Bouhova-Thacker, V. Kostyukhin, T. Koffas, W. Liebig, M. Limper, G. Piacquadio, K. Prokoiev, C. Weiser, A. Wildauer, on behalf of the ATLAS Collaboration, “Vertex Reconstruction in the ATLAS Experiment at the LHC,” CDS CERN, 29 may 2009.

Archivado bajo:Ciencia, Física, Physics, Science Tagged: Ciencia, curiosidades, experimento, Física, LHC - CERN, Noticias, partículas elementales "

Computational Complexity of Iterated Maps on the Interval. (arXiv:1003.6036v1 [cs.NA])

Computational Complexity of Iterated Maps on the Interval. (arXiv:1003.6036v1 [cs.NA]): "

The exact computation of orbits of discrete dynamical systems on the interval
is considered. Therefore, a multiple-precision floating point approach based on
error analysis is chosen and a general algorithm is presented. The correctness
of the algorithm is shown and the computational complexity is analyzed. As a
main result, the computational complexity measure considered here is related to
the Ljapunow exponent of the dynamical system under consideration.

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