Analysis of a chemo-repulsion model with nonlinear production: The continuous problem and unconditionally energy stable fully discrete schemes

We consider the following repulsive-productive chemotaxis model: Let $p\in (1,2)$, find $u \geq 0$, the cell density, and $v \geq 0$, the chemical concentration, satisfying \begin{equation}\label{C5:Am} \left\{ \begin{array} [c]{lll} \partial_t u - \Delta u - \nabla\cdot (u\nabla v)=0 \ \ \mbox{in}\ \Omega,\ t>0,\\ \partial_t v - \Delta v + v = u^p \ \ \mbox{in}\ \Omega,\ t>0, \end{array} \right. \end{equation} in a bounded domain $\Omega\subseteq \mathbb{R}^d$, $d=2,3$. By using a regularization technique, we prove the existence of solutions of this problem. Moreover, we propose three fully discrete Finite Element (FE) nonlinear approximations, where the first one is defined in the variables $(u,v)$, and the second and third ones by introducing ${\boldsymbol\sigma}=\nabla v$ as an auxiliary variable. We prove some unconditional properties such as mass-conservation, energy-stability and solvability of the schemes. Finally, we compare the behavior of the schemes throughout several numerical simulations and give some conclusions.Comment: arXiv admin note: substantial text overlap with arXiv:1807.0111

Monetary Policy Forecasting in a DSGE Model with Data that is Uncertain, Unbalanced and About the Future

If theory-consistent models can ever hope to forecast well and to be useful for policy, they have to relate to data which though rich in information is uncertain, unbalanced and sometimes forecasts from external sources about the future path of other variables. One example from many is financial market data, which can help but only after smoothing out irrelevant short-term volatility. In this paper we propose combining different types of useful but awkward data set with a linearised forward-looking DSGE model through a Kalman Filter fixed-interval smoother to improve the utility of these models as policy tools. We apply this scheme to a model for Colombia.Monetary Policy, DSGE, Forecast, Kalman Filter Classification JEL: F47, E01, C61.

Segregation-induced grain boundary electrical potential in ionic oxide materials: A first principles model

A first principles continuum analytical model for cationic segregation to the grain boundaries in complex ceramic oxides is presented. The model permits one to determine the electric charge density and the segregation-induced electric potential profiles through the grain and can be extrapolated to the range of nanostructured grain sizes. The theoretical predictions are compared with existing data for yttria-stabilized tetragonal zirconia polycrystals. The implications for physical properties (mainly high temperature plasticity and hardening behaviour) are then discussed.Gobierno de España MAT2009-14351-C02-01, MAT2009-14351-C02-0

4 and 7-bit Labeling for Projective and Non-Projective Dependency Trees

We introduce an encoding for parsing as sequence labeling that can represent any projective dependency tree as a sequence of 4-bit labels, one per word. The bits in each word's label represent (1) whether it is a right or left dependent, (2) whether it is the outermost (left/right) dependent of its parent, (3) whether it has any left children and (4) whether it has any right children. We show that this provides an injective mapping from trees to labels that can be encoded and decoded in linear time. We then define a 7-bit extension that represents an extra plane of arcs, extending the coverage to almost full non-projectivity (over 99.9% empirical arc coverage). Results on a set of diverse treebanks show that our 7-bit encoding obtains substantial accuracy gains over the previously best-performing sequence labeling encodings.Comment: Accepted for publication at EMNLP 202

Apoyo a colectivos vulnerables en la universidad. El proyecto ACCEDES

Texto apresentado no XII CIOIE - Congreso Interuniversitario de Organización de Instituciones Educativas, Simposio 7 - Organización y atención a grupos vulnerables, coordenado por Joaquín Gairín

Manual de guías de laboratorio enfocadas al control de calidad de materiales y tecnología del concreto

Trabajo de InvestigaciónEn la actualidad el laboratorio de Ingeniería Civil no cuenta con manuales de consulta que ilustren los ensayos que se ejecutan a los componentes del concreto hidráulico siguiendo los parámetros de las normar técnicas colombianas. Para una adecuada formación académica de los estudiantes es fundamental contar con herramientas que ayuden a minimizar y aclarar ciertos conceptos y procedimientos en los ensayos de laboratorio que manejan el concreto hidráulico. En consideración a esto, surge la proposición del presente trabajo. Este documento corresponde a la investigación y elaboración de un Manual de Guías de Laboratorio Enfocadas al Control de Calidad de Materiales y Tecnología de Concreto. Es un manual de guías de laboratorio es de gran importancia ya que constituye un material de apoyo para las asignaturas que tengan relación con el manejo de materiales para concreto hidráulico, también sirve de herramienta de consulta para todos los estudiantes de Ingeniería Civil y carreras afines. Estas guías de laboratorio especifican los procedimientos para cada ensayo y también los materiales que son objeto de estudio de acuerdo con las normas técnicas colombianas.PregradoIngeniero Civi