Método de exploración secuencial cuasi equilibrado en muestreo en poblaciones finitas

En este trabajo se propone un procedimiento de muestreo de tipo secuencial que proporciona probabilidades de inclusión de primer orden proporcionales al tamaño, sobre bloques de la población, siendo las de segundo orden nulas para pares de elementos similares, lo que se traduce en una disminución del error de muestreo. Para la estimación de la varianza se usa un esquema de replicación que puede ser aplicado en paralelo, bastando una única exploración de la población. Se realiza un estudio computacional comparativo con procedimientos existentes de tipo IIPS, tanto de naturaieza secuencial como no secuencial, mediante estimaciones repetidas sobre poblaciones construidas por simulación.In this paper we propose a sampling sequential procedure with first-order inclusion probabilities wich are proportiona! to size over subpopulations from the entire popuiation, and second-order inclusion probabilities equal to zero for pairs of similar units. We show that this method reduces the sampling error with respect to similar methodolagies. A replication method is used to estimate the variance. Its main advantage is that all the sampling replicatíons are obtained with only one sequential exploration of the population. The relative performance of this method, in relation with another unequal probability sampling schemes, either sequential-type or not, is studied. For that, using simulated populations, the relative errors are calculated under different sampting schemes

The use of relative priorities in optimizing the performance of a queueing system

Relative priorities in an n-class queueing system can reduce server and customer costs. This property is demonstrated in a single server Markovian model where the goal is to minimize a non-linear cost function of class expected waiting times. Special attention is given to minimizing server’s costs when the expected waiting time of each class is restricted

Localización óptima de estaciones de medición de humedad del suelo mediante clasificaciones del relieve a partir de modelos digitales del terreno

Las formas del relieve están directamente relacionadas con los procesos ambientales que sobre ellas se desarrollan, como los hidrológicos. Para estudiar estos procesos se utilizan numerosas técnicas, como la instalación de estaciones de medición de la humedad del suelo, las cuales tienen un alto coste, tanto instrumental como asociado a su montaje. A partir de Modelos Digitales del Terreno (MDT) se han realizado una serie de análisis espaciales para obtener clasificaciones geomorfométricas de las formas del relieve. Estas clasificaciones han permitido la delimitación de áreas que pueden diferenciarse por tener una humedad edáfica distinta y por desarrollar procesos hidrológicos diferentes, según el tipo de unidad geomorfométrica que representen. De esta forma se ha facilitado la selección de zonas para la instalación de las estaciones. Los resultados se han corroborado con trabajo de campo. Esta técnica se presenta como una herramienta eficaz para la obtención de la localización potencial de zonas con distinta humedad edáfica según su posición en las áreas de estudio, lo que permite reducir el tiempo y costes asociados al trabajo de campo, y permite delimitar de antemano las áreas óptimas para la instalación de las estaciones.Landforms are directly related to environmental processes that are developed on them, such as hydrology. To study these processes many techniques are used, as installation of monitoring stations for soil moisture, which have a high cost associated with both instrumental and assembly. From Digital Terrain Models (DTM) spatial analyses have been conducted in order to obtain geomorphometric landform classifications. These classifications have allowed the delimitation of areas of different soil moisture content and hydrological processes, according to the type of geomormophetric units. This has facilitated the selection of sites for the installation of soil moisture monitoring stations. Results have been verified by fieldwork. This technique appears as an effective tool for obtaining the potential location of different soil moisture content areas reducing time and economical costs associated with fieldwork and allow defining in advance the optimal areas for soil moisture monitoring installation

Investment in public transport projects in cities: What do citizens think about it?

In recent years, important public transport infrastructures projects have been carried out in Andalusia (Spain), some of them having an important impact on life in the metropolitan areas. Nevertheless, no studies have been done to know the citizens’ opinion concerning these projects. This article presents an analysis about the citizens’ perception on this matter, based on a 2015 survey with a sample of 1,200 individuals living in the Andalusian capital cities. Citizens’ perceptions about public transport infrastructures are analyzed, based on citizens’ mobility preferences, on their opinion about transport infrastructures’ social impact and about their adequation to the city they live in. Results indicate that people living in cities which already have underground have a larger preference for underground means of transport than those who live in cities that only have transit on surface. In addition, it is proved that light rail is the most unpopular transport mode among citizens.Agencia de Obra Pública de Andalucía y Unión Europea a través de "Herramienta para la evaluación previa de infraestructuras de transporte público" con código GGI3003IDIE con la colaboración de la Universidad de Granada y el Departamento de Ingeniería Civil de la Universidad de Granada

A refinement of the concept of equilibrium in multiple objective continuous games

First published in Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales in 93, 4, 1999 published by the Real Academia de Ciencias Exactas, Físicas y Naturales.This paper considers a perfection refinement of the concept of equihbrium for multiple objective non-zero sum games. Based on the ideas of van Damme (1991) on perturbed games and stability the concept of perfect equilibrium is extended to a class of continuous games with multiple objetives. Existence is shown and several relationships that exist with the corresponding concept of scalar games are stated.Dirección General de Investigación Científica y Técnic

Set-valued TU-games

The goal of this paper is to explore solution concepts for set-valued TU-games. Several stability conditions can be defined since one can have various interpretations of an improvement within the multicriteria framework. We present two different core solution concepts and explore the relationships among them. These concepts generalize the classic core solution for scalar games and can be considered under different preference structures. We give characterizations for the non-emptiness of these core sets and apply the results to four multiobjective operational research games

Clasificación de problemas verbales de álgebra elemental a partir de su resolución mediante un modelo geométrico-lineal

En el siguiente artículo presentamos los resultados de un estudio exploratorio descriptivo sobre la resolución gráfica de problemas de álgebra elemental. El estudio plantea la caracterización de un modelo de resolución gráfico, que hemos denominado modelo geométrico – lineal, y una clasificación de los problemas presentes en libros de texto a partir de su resolución utilizando dicho modelo.In the following article we show the results of a descriptive exploratory study on the elementary algebra problem solving by a graphic method. The study raises the characterization of a graphical model of resolution, that we have denominated geometrical – linear model, and a classification of the text book´s problems from its resolution using this model.No seguinte artigo apresentamos os resultados de um estudo exploratorio descritivo sobre a resolução gráfica de problemas de álgebra elementar. O estudo propõe a caracterização de um modelo de resolução gráfico, chamado modelo geométrico – lineal, e uma classificação dos problemas presentes em livros de texto a partir de sua resolução utilizando dito modelo

Multi-criteria minimum cost spanning tree games

The minimum cost spanning tree game (mcst-game) is a well-known model within operations research games that has been widely studied in the literature. In this paper we introduce the multi-criteria version of the mcst-game as a set-valued TU-game. We prove that the extension of Bird's cost allocation rule provides dominance core elements in this game. We also give a family of core solutions that are different from the previous one; these solutions are based on proportional allocations obtained using scalar solutions of the multi-criteria spanning tree problem. Besides, we prove necessary and sufficient conditions ensuring that the preference core of this game is not empty