Search results for " Programming"
showing 10 items of 1616 documents
On sampling error in evolutionary algorithms
2021
The initial population in evolutionary algorithms (EAs) should form a representative sample of all possible solutions (the search space). While large populations accurately approximate the distribution of possible solutions, small populations tend to incorporate a sampling error. A low sampling error at initialization is necessary (but not sufficient) for a reliable search since a low sampling error reduces the overall random variations in a random sample. For this reason, we have recently presented a model to determine a minimum initial population size so that the sampling error is lower than a threshold, given a confidence level. Our model allows practitioners of, for example, genetic pro…
EMERGING PROPERTIES IN POPULATION DYNAMICS WITH DIFFERENT TIME SCALES
1995
The aim of this work is to show that at the population level, emerging properties may occur as a result of the coupling between the fast micro-dynamics and the slow macrodynamics. We studied a prey-predator system with different time scales in a heterogeneous environment. A fast time scale is associated to the migration process on spatial patches and a slow time scale is associated to the growth and the interactions between the species. Preys go on the spatial patches on which some resources are located and can be caught by the predators on them. The efficiency of the predators to catch preys is patch-dependent. Preys can be more easily caught on some spatial patches than others. Perturbat…
On the Bias of Syntactic Geometric Recombination in Genetic Programming and Grammatical Evolution
2015
For fixed-length binary representations as used in genetic algorithms, standard recombination operators (e.g.,~one-point crossover) are unbiased. Thus, the application of recombination only reshuffles the alleles and does not change the statistical properties in the population. Using a geometric view on recombination operators, most search operators for fixed-length strings are geometric, which means that the distances between offspring and their parents are less than, or equal to, the distance between their parents. In genetic programming (GP) and grammatical evolution (GE), the situation is different since the recombination operators are applied to variable-length structures. Thus, most r…
The Tax Justice Network-Africa v Cabinet Secretary for National Treasury & 2 Others: A Big Win for Tax Justice Activism?
2019
This paper develops an optimization model for selecting a large subsample that improves the representativeness of a simple random sample previously obtained from a population larger than the population of interest. The problem formulation involves convex mixed-integer nonlinear programming (convex MINLP) and is therefore NP-hard. However, the solution is found by maximizing the “constant of proportionality” – in other words, maximizing the size of the subsample taken from a stratified random sample with proportional allocation – and restricting it to a p-value high enough to achieve a good fit to the population of interest using Pearson’s chi-square goodness-of-fit test. The beauty of the m…
The Fluid City Experience: An Update
2016
This chapter describes the actual status of thirteen European cities that become fluid cities through their strategies for urban regeneration. These cities are divided into three groups: the large port-cities, the medium rank “city-port” cities, the riverfront cities. For every city, we define the status of urban environment and population, the trend for port and airport traffic and the strategies for urban regeneration.
Asymptotic Hölder regularity for the ellipsoid process
2020
We obtain an asymptotic Hölder estimate for functions satisfying a dynamic programming principle arising from a so-called ellipsoid process. By the ellipsoid process we mean a generalization of the random walk where the next step in the process is taken inside a given space dependent ellipsoid. This stochastic process is related to elliptic equations in non-divergence form with bounded and measurable coefficients, and the regularity estimate is stable as the step size of the process converges to zero. The proof, which requires certain control on the distortion and the measure of the ellipsoids but not continuity assumption, is based on the coupling method.
Convergence of dynamic programming principles for the $p$-Laplacian
2018
We provide a unified strategy to show that solutions of dynamic programming principles associated to the $p$-Laplacian converge to the solution of the corresponding Dirichlet problem. Our approach includes all previously known cases for continuous and discrete dynamic programming principles, provides new results, and gives a convergence proof free of probability arguments.
Educación XX1 : revista de la Facultad de Educación
2019
Aprender a aprender es una de las competencias claves fijadas por la Comisión Europea (CE, 2005 y 2006) para los sistemas educativos de los países miembros. Las últimas investigaciones ponen de relieve la importancia de que los estudiantes universitarios aprendan a aprender, por lo que este estudio se ubica en la universidad. El objetivo es concretar un modelo teórico sobre dicha competencia que permita su operacionalización en los grados universitarios. Para ello se ha realizado una revisión de la literatura sobre el tema. Después de estudiar su fundamentación científica y la normativa reguladora, se analizaron múltiples modelos -especialmente provenientes de la literatura europea- y se pr…
Metodología innovadora en la universidad: sus efectos sobre los procesos de aprendizaje de los estudiantes universitarios
2015
Se pretendía evaluar el impacto de metodología centrada en el aprendizaje sobre las estrategias de aprendizaje y los enfoques de aprendizaje de un grupo de alumnos de Química, de 1º curso de Ingeniería, de la Universitat Politécnica de Valencia. Se utilizó un diseño preexperimental, con medidas de pretest y postest, tomadas mediante el cuestionario CEVEAPEU y el CPE. La muestra estaba constituida por 20 alumnos. Los métodos docentes utilizados integraban metodología expositiva, preguntas, resolución de problemas, elaboración de una monografía, exposiciones orales, prácticas de laboratorio, trabajo en grupo, tutorías en el aula y un sistema de evaluación que hacía uso de procedimientos forma…
An evolutionary perspective on stress responses, damage and repair
2022
Variation in stress responses has been investigated in relation to environmental factors, species ecology, life history and fitness. Moreover, mechanistic studies have unravelled molecular mechanisms of how acute and chronic stress responses cause physiological impacts (‘damage’), and how this damage can be repaired. However, it is not yet understood how the fitness effects of damage and repair influence stress response evolution. Here we study the evolution of hormone levels as a function of stressor occurrence, damage and the efficiency of repair. We hypothesise that the evolution of stress responses depends on the fitness consequences of damage and the ability to repair that damage. To o…