Nodal collocation method for the multidimensional PL equations applied to neutron transport source problems

A PL spherical harmonics-nodal collocation method is applied to the solution of the multidimensional neutron source transport equation. Vacuum boundary conditions are approximated by setting Marshak's conditions. The method is applied to several 1D, 2D and 3D problems with isotropic fixed source and with isotropic and anisotropic scattering. These problems are chosen to test this method in limit conditions, showing that in some cases a high order $P_L$ approximation is required to obtain accurate results and convergence. Results are also compared with the ones provided by several reference codes showing good agreement. It is also shown that Marshak's approximation to vacuum boundary conditions gives the same results that simulating vacuum with a purely absorbing medium and setting zero flux boundary conditions.This work has been partially supported by the Spanish Ministerio de Economia y Competitividad under project ENE2011-22823, and the Generalitat Valenciana under project PROMETEO11/2014/008.Capilla Romá, MT.; Talavera Usano, CF.; Ginestar Peiro, D.; Verdú Martín, GJ. (2016). Nodal collocation method for the multidimensional PL equations applied to neutron transport source problems. Annals of Nuclear Energy. 87:89-100. https://doi.org/10.1016/j.anucene.2015.07.040S891008

A study of the radiative transfer equation using a spherical harmonics-nodal collocation method

[EN] Optical tomography has found many medical applications that need to know how the photons interact with the different tissues. The majority of the photon transport simulations are done using the diffusion approximation, but this approximation has a limited validity when optical properties of the different tissues present large gradients, when structures near the photons source are studied or when anisotropic scattering has to be taken into account. As an alternative to the diffusion model, the PL equations for the radiative transfer problem are studied. These equations are discretized in a rectangular mesh using a nodal collocation method. The performance of this model is studied by solving different 1D and 2D benchmark problems of light propagation in tissue having media with isotropic and anisotropic scattering.This work has been partially supported by the Spanish Ministerio de Economia y Competitividad under project ENE-2014-59442-P and by the Generalitat Valenciana under project PRO-METE II/2014/008.Capilla Romá, MT.; Talavera Usano, CF.; Ginestar Peiro, D.; Verdú Martín, GJ. (2017). A study of the radiative transfer equation using a spherical harmonics-nodal collocation method. Journal of Quantitative Spectroscopy and Radiative Transfer. 189:25-36. https://doi.org/10.1016/j.jqsrt.2016.11.008S253618

A new well-balanced non-oscillatory central scheme for the shallow water equations on rectangular meshes

This paper is concerned with the development of high-order well-balanced central schemes to solve the shallow water equations in two spatial dimensions. A Runge Kutta scheme is applied for time discretization. A Gaussian quadrature rule is used to evaluate time integrals and a three-degree polynomial which calculates point-values or flux values. A new procedure has been defined to evaluate the flux integrals and to approach the 2D source term integrals in order to verify the exact C-property, using the water surface elevation instead of the water depth as a variable. Numerical experiments have confirmed the high-resolution properties of our numerical scheme in 2D test problems.This work was partially funded by the "Programa de Apoyo a la Investigacion y Desarrollo" (PAID-06-10) and (PAID-05-12) of the Universidad Politecnica de Valencia. Angel Balaguer-Beser thanks the support of the Spanish Ministry of Education and Science in the framework of the Projects CGL2009-14220-C02-01 and CGL2010-19591. The authors express their gratitude to the anonymous reviewers for their helpful comments.Capilla Romá, MT.; Balaguer Beser, ÁA. (2013). A new well-balanced non-oscillatory central scheme for the shallow water equations on rectangular meshes. Journal of Computational and Applied Mathematics. 252:62-74. https://doi.org/10.1016/j.cam.2013.01.014S627425

Evaluación continua, clase inversa y cooperación activa en Matemáticas para ingenieros

La Universitat Politècnica de Valencia (UPV) facilita la creación de equipos de innovación y calidad educativa (EICE). Uno de dichos equipos es GRIM4E (GRoup of Innnovative Methodologies and Assessment For Engineering education) que comenzó a realizar innovaciones metodológicas al adaptar las asignaturas de matemáticas a los grados surgidos dentro del proceso de Bolonia. Algunas de dichas innovaciones ya habían sido iniciadas con anterioridad como una evaluación continua de todas las actividades de aprendizaje desarrolladas durante el curso, con más de 30 actos de evaluación en la actualidad en las asignaturas anuales y 10 en las semestrales. Otras fueron pioneras como el empleo sistemático de la clase inversa en las prácticas informáticas de las asignaturas involucradas. Una innovación reciente destacada en nuestro ámbito ha sido el fomento de una actitud activa y colaborativa de los alumnos en la preparación de los actos de evaluación más relevantes.En este trabajo presentamos estas líneas desarrolladas por GRIM4E e incluimos resultados de encuestas anónimas realizadas para recabar la percepción de los alumnos sobre la metodología mixta empleada

Effective Tool Support for Architectural Knowledge Sharing

Abstract. Knowledge management plays an important role in the software architecting process. Recently, this role has become more apparent by a paradigm shift that views a software architecture as the set of architectural design decisions it embodies. This shift has sparked the discussion in both research and practice on how to best facilitate sharing of so-called architectural knowledge, and how tools can best be employed. In order to design successful tool support for architectural knowledge sharing it is important to take into account what software architecting really entails. To this end, in this paper we define the main characteristics of architecting, based on observations in a large software development organization, and state-of-the-art literature in software architecture. Based on the defined characteristics, we determine how best practices known from knowledge management could be used to improve architectural knowledge sharing. This results in the definition of a set of desired properties of architectural knowledge sharing tools. To improve the status quo of architectural knowledge sharing tools, we present the design of an architectural knowledge sharing platform.