Estimación de un modelo de comportamiento exportador para la empresa española: aplicación del método LISREL

El presente estudio parte de dos aseveraciones. En primer lugar, es admitido que la exportación constituye una de las variables estratégicas básicas en el comportamiento dinámico de una economía moderna. La segunda aseveración tiene que ver con un cambio percibido en la forma de estudiar este ámbito de la realidad económica: existe la convicción, cada vez más generalizada, de que para detectar las ventajas comerciales de un país no basta con investigar, de forma agregada, las bases de su especialización sectorial. Es necesario complementar esa óptica con un análisis más detallado de las ventajas específicas atribuidas a sus empresas; pues, en efecto, son las empresas las encargadas de proyectar las ventajas genéricas de un país en forma de ventajas competitivas en los mercados internacionales. Es más, la creciente interconexión entre los mercados no hace sino revalorizar el papel que la empresa tiene como portador específico de capacidades competitivas

Calidad institucional y cohesión social: El corrosivo efecto de la desigualdad

El artículo persigue mostrar que la desigualdad, especialmente cuando afecta a grupos sociales (desigualdad horizontal) y se acompaña de baja movilidad social, constituye un importante factor que deteriora la calidad de las instituciones. Para ello, analiza el papel que la desigualdad tiene entre los criterios de evaluación de la calidad institucional y discute el tipo de desigualdad que es más relevante por su impacto sobre las instituciones. A través del recurso a dos ejercicios empíricos, empleando métodos econométricos diferentes, se comprueba que la desigualdad es un determinante relevante (con signo negativo) de la calidad institucional. Las estimaciones sugieren que es difícil construir buenas instituciones en sociedades altamente fragmentadas, con niveles de desigualdad elevado y cronificado en el tiempo. Esos resultados inspiran una reflexión sobre el caso español en los años más recientes

Learning Bayesian network classifiers for multidimensional supervised classification problems by means of a multiobjective approach

A classical supervised classification task tries to predict a single class variable based on a data set composed of a set of labeled examples. However, in many real domains more than one variable could be considered as a class variable, so a generalization of the single-class classification problem to the simultaneous prediction of a set of class variables should be developed. This problem is called multi-dimensional supervised classification. In this paper, we deal with the problem of learning Bayesian net work classifiers for multi-dimensional supervised classification problems. In order to do that, we have generalized the classical single-class Bayesian network classifier to the prediction of several class variables. In addition, we have defined new classification rules for probabilistic classifiers in multi-dimensional problems. We present a learning approach following a multi-objective strategy which considers the accuracy of each class variable separately as the functions to optimize. The solution of the learning approach is a Pareto set of non-dominated multi-dimensional Bayesian network classifiers and their accuracies for the different class variables, so a decision maker can easily choose by hand the classifier that best suits the particular problem and domain

Radio does not die on the air: Podcasting and on-demand broadcast strategies among speech-based radio stations

In recent decades, speech-based radio stations in Spain, whose programmes have been aimed at the general public, have transformed their on-demand content broadcasting strategy by incorporating audio processes in the form of podcasts, followed by transmission through websites, aggregators and applications. The overall objective of this article is to provide a detailed account of the evolution and scope of the podcast as an on-demand distribution channel for speech-based Spanish radio broadcasters, and to reveal how this format is changing the approaches taken by the most prominent national radio stations [Cadena SER, COPE, Onda Cero, and Radio Nacional de España (RNE)], with special emphasis on prime-time morning shows. The methodology employed combines quantitative and qualitative techniques along with an analysis of the content uploaded to the website of these morning programmes, which are part of the weekly programming cycle, together with semi-structured interviews using closed-ended questions that have been given to the main heads of programming and digital areas of the broadcasters under study. The results show that radio stations have incorporated podcast distribution into their usual routine in order to give new life to the content emitted, with the aim of serving both traditional users as well as new generations of digitised native listeners. In addition, they process daily content in an increasingly systematic way, on the basis of a model of mixed management coordination between programmes and digital areas. Similarly, broadcasters have made considerable progress in the measurement and analysis of the time-shifted audience, as well as in broadcast multiplication techniques using push notifications, social media, and monetisation

Aportaciones Metodológicas de la Investigación a la Docencia

La presente ponencia constituye un ejercicio de aplicación de la metodología de investigación a la docencia. De este modo se identificarán las principales actividades de la metodología investigadora, y se verá cómo éstas se pueden utilizar para construir en torno a ellas una asignatura. Se realizará también un análisis de las capacidades, habilidades y conocimientos generales que potencia este tipo de metodología

Advanced titanium scaffolds obtained by directional freeze-drying: on the influence of processing conditions

Ministry of Science and Innovation of Spain under Grant No. MAT2010-20855Junta de Andalucía (Spain) / FEDER (EU), through the project Ref. P12-TEP-140

A sensitivity study of bias and variance of k-fold cross-validation in prediction error estimation

In the machine learning field the performance of a classifier is usually measured in terms of prediction error. In most real-world problems, the error cannot be exactly calculated and it must be estimated. Therefore, it’s important to choose an appropriate estimator of the error. This paper analyzes the statistical properties (bias and variance) of the k-fold cross-validation classification error estimator (k-cv). Our main contribution is a novel theoretical decomposition of the variance of the k-cv considering its sources of variance: sensitivity to changes in the training set and sensitivity to changes in the folds. The paper also compares the bias and variance of the estimator for different values of k. The empirical study has been performed in artificial domains because they allow the exact computation of the implied quantities and we can specify rigorously the conditions of experimentation. The empirical study has been performed for two different classifiers (naïve Bayes and nearest neighbor), different number of folds (2, 5, 10, n) and sample sizes, and training sets coming from assorted probability distributions

Flipped Learning Approach as Educational Innovation in Water Literacy

Water literacy has become a fundamental aspect in today’s society, as its conservation, preservation and management is key to ensuring human survival. The purpose of this paper was to analyze the effectiveness of flipped learning methodology on a traditional training practice in water literacy at the first level of secondary education. The flipped learning method consisted in providing the contents to the students before the class sessions, encouraging an active learning. A descriptive study was adopted with two experimental groups, two control groups and only post-test. An ad hoc questionnaire was used as an instrument to measure the parameters: Socio-educational, Motivation, Interactions, Autonomy, Collaboration; Deepening of contents; Problem solving, Class time and Ratings. The final sample was composed of 120 students, divided into four groups of 30 students each. The application of the treatment in the experimental groups lasted 10 sessions of 55 min. The results indicate that the use of time in class, the autonomy and the deepening of the contents were the aspects that improved most with the flipped learning approach. However, no significant differences in ratings were found. Finally, the main findings and their implications for water literacy are discussed.Ministry of Education, Culture and Sport of the Government of Spain (Project reference: FPU16/01762)