Improving NDT with Automatic Test Case Generation

The model-driven development defi nes the software development process as a set of iterations to create models and a set of transformations to obtain new models. From this point of view, this paper presents the enhancement of a model- driven approach, called navigational development techniques (NDT), by means of new models and transformations in order to generate test cases. It also states some conclusions from the research work and practical cases in which this approach was used.Ministerio de Ciencia e Innovación TIN2010-20057-C03-02Ministerio de Ciencia e Innovación TIN 2010-12312-

The euro effect on trade: evidence in gravity equations using panel cointegration techniques

In this paper we present new evidence on the effect of the Euro on trade. We use a data set containing all bilateral combinations in a panel of 26 countries covering the period 1967-2008. We estimate the equation using two sets of variables: a standard one and a second one built according to the criticisms stated by Baldwin and Taglioni (2006). We implement a new generation of tests that allow us to solve some of the problems derived from the non-stationary nature of the data usually present in the macroeconomic variables used in gravitational equations (GDP, trade). To this aim we use some panel tests that account for the presence of cross-section dependence as well as discontinuities in the non-stationary panel data series. We test for cointegration between the variables using panel cointegration tests, especially the ones proposed by Banerjee and Carrión-i-Silvestre (2004, 2010). We also efficiently estimate the long-run relationships using the CUP-BC and CUP-FM estimators proposed in Bai et al. (2009). The results obtained are in line with those of Bun and Klaassen (2007). We argue that the creation of the European Monetary Union is best interpreted as a culmination of a series of policy changes that have been increasing economic integration in Europe during over four decades. En este trabajo presentamos nueva evidencia del efecto del Euro sobre el comercio. En este trabajo presentamos nueva evidencia del efecto del Euro sobre el comercio. Para ello utilizamos una base de datos que contiene todas las combinaciones bilaterales en un panel de 26 países para el periodo 1967-2008. Estimamos la ecuación de gravedad usando dos tipos de variables: la estándar en la literatura y la que recoge las críticas de Baldwin y Taglioni (2006), aplicando una nueva generación de contrastes que nos permiten resolver los principales problemas derivados de la naturaleza no estacionaria de las series. Con este propósito utilizamos algunos contrastes de panel que tienen en cuenta la presencia de dependencia cross-section así como de rupturas en las series. Para realizar el análisis de cointegración cabe destacar el uso del contraste de Banerjee y Carrion-i-Silvestre (2006, 2010). También estimamos de forma eficiente las relaciones de largo plazo mediante los estimadores CUPpc y CUPfm propuestos por Bai et al. (2009). Los resultados obtenidos están en línea con los de Bun y Klaassen (2007). Nuestro argumento es que la creación de la Unión Monteria Europea se debe interpretar como la culminación de un conjunto de cambios de política que han ido dando lugar a un proceso de integración económica en Europa durante las últimas cuatro décadas.modelos de gravedad; comercio; cointegración con paneles; factores comunes; cambios estructurales; dependencia. gravity models; trade; panel cointegration; common factors; structural breaks, cross-section dependence.

Statistical Complexity and Nontrivial Collective Behavior in Electroencephalografic Signals

We calculate a measure of statistical complexity from the global dynamics of electroencephalographic (EEG) signals from healthy subjects and epileptic patients, and are able to stablish a criterion to characterize the collective behavior in both groups of individuals. It is found that the collective dynamics of EEG signals possess relative higher values of complexity for healthy subjects in comparison to that for epileptic patients. To interpret these results, we propose a model of a network of coupled chaotic maps where we calculate the complexity as a function of a parameter and relate this measure with the emergence of nontrivial collective behavior in the system. Our results show that the presence of nontrivial collective behavior is associated to high values of complexity; thus suggesting that similar dynamical collective process may take place in the human brain. Our findings also suggest that epilepsy is a degenerative illness related to the loss of complexity in the brain.Comment: 13 pages, 3 figure

An Analysis of Model-Driven Web Engineering Methodologies

In the late 1990’s there was substantial activity within the “Web engineering” research community and a multitude of new Web approaches were proposed. However, numerous studies have revealed major gaps in these approaches, including coverage and interoperability. In order to address these gaps, the Model-Driven Engineering (MDE) paradigm offers a new approach which has been demonstrated to achieve good results within applied research environments. This paper presents an analysis of a selection of Web development methodologies that are using the MDE paradigm in their development process and assesses whether MDE can provide an effective solution to address the aforementioned problems. This paper presents a critical review of previous studies of classical Web methodologies and makes a case for the potential of the MDWE paradigm as a means of addressing long-standing problems of Web development, for both research and enterprise. A selection of the main MDWE development approaches are analyzed and compared in accordance with criteria derived from the literature. The paper concludes that this new trend opens an interesting new way to develop Web systems within practical projects and argues that some classical gaps can be improved with MDWE.Ministerio de Educación y Ciencia TIN2010-12312-EJunta de Andalucía TIC-578

PROPIEDADES CÍCLICAS Y CAMBIOS ESTRUCTURALES EN LAS SERIES FISCALES MACROECONÓMICAS DE LA ECONOMÍA ESPAÑOLA

En este trabajo se estudian las propiedades cíclicas de las variables fiscales macroeconómicas de la economía española utilizando la metodología de los "hechos estilizados" de los ciclos económicos. Además, se intenta clasificar los distintos cambios de régimen de la política fiscal española, utilizando recientes contrastes econométricos capaces de captar la existencia de cambios estructurales y detectar endógenamente el posible punto en que se producen. Classification-JEL : E3, E6, H3, H6.finanzas, ciclo económico, propiedades cíclicas, cambios estructurales

Minimal approach to neuro-inspired information processing

© 2015 Soriano, Brunner, Escalona-Morán, Mirasso and Fischer. To learn and mimic how the brain processes information has been a major research challenge for decades. Despite the efforts, little is known on how we encode, maintain and retrieve information. One of the hypothesis assumes that transient states are generated in our intricate network of neurons when the brain is stimulated by a sensory input. Based on this idea, powerful computational schemes have been developed. These schemes, known as machine-learning techniques, include artificial neural networks, support vector machine and reservoir computing, among others. In this paper, we concentrate on the reservoir computing (RC) technique using delay-coupled systems. Unlike traditional RC, where the information is processed in large recurrent networks of interconnected artificial neurons, we choose a minimal design, implemented via a simple nonlinear dynamical system subject to a self-feedback loop with delay. This design is not intended to represent an actual brain circuit, but aims at finding the minimum ingredients that allow developing an efficient information processor. This simple scheme not only allows us to address fundamental questions but also permits simple hardware implementations. By reducing the neuro-inspired reservoir computing approach to its bare essentials, we find that nonlinear transient responses of the simple dynamical system enable the processing of information with excellent performance and at unprecedented speed. We specifically explore different hardware implementations and, by that, we learn about the role of nonlinearity, noise, system responses, connectivity structure, and the quality of projection onto the required high-dimensional state space. Besides the relevance for the understanding of basic mechanisms, this scheme opens direct technological opportunities that could not be addressed with previous approaches.The authors acknowledge support by MINECO (Spain) under Projects TEC2012-36335 (TRIPHOP) and FIS2012-30634 (Intense@cosyp), FEDER and Govern de les Illes Balears via the program Grups Competitius. The work of MS was supported by the Conselleria d'Educació, Cultura i Universitats del Govern de les Illes Balears and the European Social Fund.Peer Reviewe

Vortices and domain walls in a Chern-Simons theory with magnetic moment interaction

We study the structure and properties of vortices in a recently proposed Abelian Maxwell-Chern-Simons model in $2 +1$ dimensions. The model which is described by gauge field interacting with a complex scalar field, includes two parity and time violating terms: the Chern-Simons and the anomalous magnetic terms. Self-dual relativistic vortices are discussed in detail. We also find one dimensional soliton solutions of the domain wall type. The vortices are correctly described by the domain wall solutions in the large flux limit.Comment: To be published in Phys RevD 23 pages, RevTex, 5 figure

Applying Model-Driven Paradigm for the Improvement of Web Requirement Validation

This paper proposes an approach for Web requirements validation by applying the model-driven paradigm in classical requirements validation techniques. In particular, we present how the Navigational Development Techniques (NDT) approach exploits the model-driven paradigm to improve its requirements validation task by exploring tool cases that systematize or even automate the application of requirements validation techniques. Our solution is validated by applying it in a real industrial environment. The results and the learned lessons are presented accordingly