Can FDI promote export diversification and sophistication of host countries? : dynamic panel system GMM analysis

Recent trade literature highlights the importance of export diversification and upgrading in fostering faster and sustainable economic growth. This study investigates the impact of FDI inflow and stock on the level of export diversification and sophistication in host country's export baskets. By utilizing the dynamic panel data model, we find that the five-year lagged FDI inflow correlates positively with both export diversification and sophistication, and FDI stock makes the positive contribution to export sophistication. These findings provide support for the possibility of successful capabilities transfer to and building by local firms. We also find that these positive impacts of FDI exist only in developing countries.

Parallel execution of Prolog programs: a survey

Since the early days of logic programming, researchers in the field realized the potential for exploitation of parallelism present in the execution of logic programs. Their high-level nature, the presence of nondeterminism, and their referential transparency, among other characteristics, make logic programs interesting candidates for obtaining speedups through parallel execution. At the same time, the fact that the typical applications of logic programming frequently involve irregular computations, make heavy use of dynamic data structures with logical variables, and involve search and speculation, makes the techniques used in the corresponding parallelizing compilers and run-time systems potentially interesting even outside the field. The objective of this article is to provide a comprehensive survey of the issues arising in parallel execution of logic programming languages along with the most relevant approaches explored to date in the field. Focus is mostly given to the challenges emerging from the parallel execution of Prolog programs. The article describes the major techniques used for shared memory implementation of Or-parallelism, And-parallelism, and combinations of the two. We also explore some related issues, such as memory management, compile-time analysis, and execution visualization.

Generating Awareness from Collaborative Working Environment using Social Data

Nowadays, Internet is a place where social networks have reached an important impact in collaboration among people over the world in different ways. This article proposes a new paradigm for building CSCW business tools following the novel ideas provided by the social web to collaborate and generate awareness. An implementation of these concepts is described, including the components we provide to collaborate in workspaces, (such as videoconference, chat, desktop sharing, forums or temporal events), and the way we generate awareness from these complex social data structures. Figures and validation results are also presented to stress that this architecture has been defined to support awareness generation via joining current and future social data from business and social networks worlds, based on the idea of using social data stored in the cloud.

Cloud Computing Service for Managing Large Medical Image Data-Sets Using Balanced Collaborative Agents

Managing large medical image collections is an increasingly demanding important issue in many hospitals and other medical settings. A huge amount of this information is daily generated, which requires robust and agile systems. In this paper we present a distributed multi-agent system capable of managing very large medical image datasets. In this approach, agents extract low-level information from images and store them in a data structure implemented in a relational database. The data structure can also store semantic information related to images and particular regions. A distinctive aspect of our work is that a single image can be divided so that the resultant sub-images can be stored and managed separately by different agents to improve performance in data accessing and processing. The system also offers the possibility of applying some region-based operations and filters on images, facilitating image classification. These operations can be performed directly on data structures in the database.

Parallelizing irregular and pointer-based computations automatically: perspectives from logic and constraint programming

Irregular computations pose sorne of the most interesting and challenging problems in automatic parallelization. Irregularity appears in certain kinds of numerical problems and is pervasive in symbolic applications. Such computations often use dynamic data structures, which make heavy use of pointers. This complicates all the steps of a parallelizing compiler, from independence detection to task partitioning and placement. Starting in the mid 80s there has been significant progress in the development of parallelizing compilers for logic pro­gramming (and more recently, constraint programming) resulting in quite capable paralle­lizers. The typical applications of these paradigms frequently involve irregular computations, and make heavy use of dynamic data structures with pointers, since logical variables represent in practice a well-behaved form of pointers. This arguably makes the techniques used in these compilers potentially interesting. In this paper, we introduce in a tutoríal way, sorne of the problems faced by parallelizing compilers for logic and constraint programs and provide pointers to sorne of the significant progress made in the area. In particular, this work has resulted in a series of achievements in the areas of inter-procedural pointer aliasing analysis for independence detection, cost models and cost analysis, cactus-stack memory management, techniques for managing speculative and irregular computations through task granularity control and dynamic task allocation such as work-stealing schedulers), etc.

Sharing analysis of arrays, collections, and recursive structures

Precise modeling of the program heap is fundamental for understanding the behavior of a program, and is thus of signiflcant interest for many optimization applications. One of the fundamental properties of the heap that can be used in a range of optimization techniques is the sharing relationships between the elements in an array or collection. If an analysis can determine that the memory locations pointed to by different entries of an array (or collection) are disjoint, then in many cases loops that traverse the array can be vectorized or transformed into a thread-parallel versión. This paper introduces several novel sharing properties over the concrete heap and corresponding abstractions to represent them. In conjunction with an existing shape analysis technique, these abstractions allow us to precisely resolve the sharing relations in a wide range of heap structures (arrays, collections, recursive data structures, composite heap structures) in a computationally efflcient manner. The effectiveness of the approach is evaluated on a set of challenge problems from the JOlden and SPECjvm98 suites. Sharing information obtained from the analysis is used to achieve substantial thread-level parallel speedups.

Automatic parallelization of irregular and pointer-based computations: perspectives from logic and constraint programming

Irregular computations pose some of the most interesting and challenging problems in automatic parallelization. Irregularity appears in certain kinds of numerical problems and is pervasive in symbolic applications. Such computations often use dynamic data structures which make heavy use of pointers. This complicates all the steps of a parallelizing compiler, from independence detection to task partitioning and placement. In the past decade there has been significant progress in the development of parallelizing compilers for logic programming and, more recently, constraint programming. The typical applications of these paradigms frequently involve irregular computations, which arguably makes the techniques used in these compilers potentially interesting. In this paper we introduce in a tutorial way some of the problems faced by parallelizing compilers for logic and constraint programs. These include the need for inter-procedural pointer aliasing analysis for independence detection and having to manage speculative and irregular computations through task granularity control and dynamic task allocation. We also provide pointers to some of the progress made in these áreas. In the associated talk we demónstrate representatives of several generations of these parallelizing compilers.

Análisis dinámico experimental de edificios esbeltos

Es conocido que la variación del comportamiento dinámico de las estructuras puede ser empleado dentro de un sistema de monitorización de su integridad estructural. Así, este estudio tiene como objetivo comprender el comportamiento dinámico de edificios esbeltos, frente a diferentes agentes ambientales como la temperatura y/o dirección y velocidad del viento. En el marco de esta investigación, se estudian dos edificios: la Torre de la ETSI (Escuela Técnica Superior de Ingenieros) de Caminos, Canales y Puertos de la UPM (Universidad Politécnica de Madrid) y un edificio de viviendas situado en la calle de Arturo Soria de Madrid. Los datos medioambientales antes mencionados, se registraron con sendas estacionales meteorológicas situadas en las azoteas de ambos edificios. Se realiza el análisis modal operacional de ambas estructuras. Este análisis se realiza a partir de las mediciones de las aceleraciones ante excitaciones ambientales, es un análisis basado sólo en la respuesta de la estructura. Por tanto, no es necesario interrumpir el funcionamiento en servicio de la instalación, obteniendo su comportamientos en este estado. A partir de este análisis, se obtienen las frecuencias naturales, los amortiguamientos modales y las formas modales. Así, en este trabajo se ha estudiado la relación existente entre la variación en la estimación de las frecuencias naturales y la variación de los agentes ambientales (fundamentalmente la temperatura). Los ensayos dinámicos en los dos edificios mencionados anteriormente, se han realizado utilizando acelerómetros de alta sensibilidad sincronizados inalámbricamente, lo cual ha simplificado el trabajo experimental si lo comparamos con los sistemas tradicionales. Como resultado del trabajo realizado se pueden destacar los siguientes puntos: (i) se ha visto que con el equipamiento disponible se pueden realizar análisis dinámicos de edificios, (ii) se ha mejorado el conocimiento dinámico de estas estructuras, y (iii) se ha visto la importancia que pueden tener los agentes ambientales dependiendo por un lado del tipo estructura del edificio. A partir del trabajo, se podrían actualizar modelos matemáticos que sirvan para la predicción de daños en las estructuras, y por otro, se podrán eliminar los efectos de los agentes ambientales, lo cual es un punto vital si se quiere emplear los parámetros modales para el cálculo de indices de daño. La aplicación de este tipo de investigación ayudará a tener una información mayor sobre el comportamiento de las estructuras y así, en el futuro, poder realizar distintos tipos de procesos, como la formulación de modelos matemáticos que reflejen con mayor fidelidad el comportamiento real. De esta forma, la monitorización de los agentes medioambientales permitirán valorar la influencia de estas variaciones sobre la estructura pudiéndose eliminar estos efectos. Con ello, se mejora la incertidumbre en la variación de frecuencias que puede ser utilizada como un sistema de activación de alarmas frente a la detección de daños estructurales. It is known that the variation of the dynamic behavior of structures can be used within a system to monitor structural integrity. So, this study aims to understand the dynamic behavior of slender buildings, against different environmental agents such as temperature and / or wind direction and velocity. As part of this investigation, two buildings are studied: the ETSI's (Escuela Técnica Superior de Ingenieros) main tower of Escuela de Caminos, Canales y Puertos of UPM (Universidad Politécnica de Madrid) and a residential building located in the streets Arturo Soria Madrid. The environmental data were recorded with weather stations located on the roof of both buildings. In both structures a modal operational analysis has been carried out. This analysis is performed from the measurements of the acceleration to the environmental excitation, this analysis is based only on the response of the structure. Therefore, it is not necessary to interrupt the operation of the structure, getting its behavior in this state. From this analysis, the natural frequencies, modal damping and mode shapes are obtained. So, in this work we have studied the existing relationship between the variation in the estimate of the natural frequencies and the variation of environmental agents (mainly temperature). The dynamic tests in the two buildings mentioned above, have been made using high-sensitivity accelerometers wirelessly synchronized, which has simplified the experimental work when compared to traditional systems. As a result of work performed can highlight the following points: (i) it has been found that with the available equipment can perform dynamic analysis of buildings, (ii) has improved dynamic knowledge of these structures, and, (iii) can be seen the potential importance of environmental agents depending on the type of building structure. From the work, mathematical models can be updated that serve to prediction of damage to structures, and on the other side, may eliminate the effects of environmental agents, which is a vital point if you want to use the modal parameters for calculating damage ratings. The application of this type of research will help to have more information about the behavior of structures and so, in the future, conduct various processes, as the formulation of mathematical models that reflect more accurately an actual behavior. In this way the monitoring of environmental agents will allow evaluate the influence of these variations on the structure being possible eliminate these effects. Thereby, improvement the uncertainty in the frequencies variation that can be used as an alarm activation system from detection of structural damage.

Influencia de un fluido en las características dinámicas de placas circulares y casicirculares

La influencia de un fluido en las características dinámicas de estructuras se ha estudiado desde hace tiempo. Sin embargo muchos estudios se refieren a aplicaciones bajo el agua, como es el caso del sonar de un submarino por lo que el fluido circundante se considera líquido (sin efectos de compresibilidad). Más recientemente en aplicaciones acústicas y espaciales tales como antenas o paneles muy ligeros, ha sido estudiada la influencia en las características dinámicas de una estructura rodeada por un fluido de baja densidad. Por ejemplo se ha mostrado que el efecto del aire en el transmisor-reflector del Intelsat VI C-B con un diámetro de 3,2 metros y con un peso de sólo 34,7 kg disminuye la primera frecuencia en torno a un 20% con respecto a su valor en vacío. Por tanto es importante en el desarrollo de estas grandes y ligeras estructuras disponer de un método con el que estimar el efecto del fluido circundante sobre las frecuencias naturales de éstas. De esta manera se puede evitar el ensayo de la estructura en una cámara de vacío que para el caso de una gran antena o panel puede ser difícil y costoso. Se ha desarrollado un método de elementos de contorno (BEM) para la determinación del efecto del fluido en las características dinámicas de una placa circular. Una vez calculados analíticamente los modos de vibración de la placa en vacío, la matriz de masa añadida debido a la carga del fluido se determina por el método de elementos de contorno. Este método utiliza anillos circulares de manera que el número de elementos para obtener unos resultados precisos es muy bajo. Se utiliza un procedimiento de iteración para el cálculo de las frecuencias naturales del acoplamiento fluido-estructura para el caso de fluido compresible. Los resultados del método se comparan con datos experimentales y otros modelos teóricos mostrando la precisión y exactitud para distintas condiciones de contorno de la placa. Por otro lado, a veces la geometría de la placa no es circular sino casi-circular y se ha desarrollado un método de perturbaciones para determinar la influencia de un fluido incompresible en las características dinámicas de placas casi-circulares. El método se aplica a placas con forma elíptica y pequeña excentricidad. Por una parte se obtienen las frecuencias naturales y los modos de deformación de la placa vibrando en vacío. A continuación, se calculan los coeficientes adimensionales de masa virtual añadida (factores NAVMI). Se presentan los resultados de estos factores y el efecto del fluido en las frecuencias naturales. ABSTRACT The influence of the surrounding fluid on the dynamic characteristics of structures has been well known for many years. However most of these works were more concerned with underwater applications, such as the sonar of a submarine and therefore the surrounding fluid was considered a liquid (negligible compressibility effects). Recently for acoustical and spatial applications such as antennas or very light panels the influence on the dynamic characteristics of a structure surrounded by a fluid of low density has been studied. Thus it has been shown that the air effect for the Intelsat VI C-B transmit reflector with a diameter of 3,2 meters and weighting only 34,7 kg decreases the first modal frequency by 20% with respect to the value in vacuum. It is important then, in the development of these light and large structures to have a method that estimates the effect that the surrounding fluid will have on the natural frequencies of the structure. In this way it can be avoided to test the structure in a vacuum chamber which for a large antenna or panel can be difficult and expensive A BEM method for the determination of the effect of the surrounding fluid on the dynamic characteristics of a circular plate has been developed. After the modes of the plate in vacuum are calculated in an analytical form, the added mass matrix due to the fluid loading is determined by a boundary element method. This method uses circular rings so the number of elements to obtain an accurate result is very low. An iteration procedure for the computation of the natural frequencies of the couple fluid-structure system is presented for the case of the compressibility effect of air. Comparisons of the present method with various experimental data and other theories show the efficiency and accuracy of the method for any support condition of the plate. On the other hand, sometimes the geometry of the plate is not circular but almost-circular, so a perturbation method is developed to determine the influence of an incompressible fluid on the dynamic characteristics of almost-circular plates. The method is applied to plates of elliptical shape with low eccentricity. First, the natural frequencies and the mode shapes of the plate vibrating in vacuum are obtained. Next, the nondimensional added virtual mass coefficients (NAVMI factors) are calculated. Results of this factors and the effect of the fluid on the natural frequencies are presented.

LiDAR remote sensing applied to forest resources assessment

Disponer de información precisa y actualizada de inventario forestal es una pieza clave para mejorar la gestión forestal sostenible y para proponer y evaluar políticas de conservación de bosques que permitan la reducción de emisiones de carbono debidas a la deforestación y degradación forestal (REDD). En este sentido, la tecnología LiDAR ha demostrado ser una herramienta perfecta para caracterizar y estimar de forma continua y en áreas extensas la estructura del bosque y las principales variables de inventario forestal. Variables como la biomasa, el número de pies, el volumen de madera, la altura dominante, el diámetro o la altura media son estimadas con una calidad comparable a los inventarios tradicionales de campo. La presente tesis se centra en analizar la aplicación de los denominados métodos de masa de inventario forestal con datos LIDAR bajo diferentes condiciones y características de masa forestal (bosque templados puros y mixtos) y utilizando diferentes bases de datos LiDAR (información proveniente de vuelo nacionales e información capturada de forma específica). Como consecuencia de lo anterior, se profundiza en la generación de inventarios forestales continuos con LiDAR en grandes áreas. Los métodos de masa se basan en la búsqueda de relaciones estadísticas entre variables predictoras derivadas de la nube de puntos LiDAR y las variables de inventario forestal medidas en campo con el objeto de generar una cartografía continua de inventario forestal. El rápido desarrollo de esta tecnología en los últimos años ha llevado a muchos países a implantar programas nacionales de captura de información LiDAR aerotransportada. Estos vuelos nacionales no están pensados ni diseñados para fines forestales por lo que es necesaria la evaluación de la validez de esta información LiDAR para la descripción de la estructura del bosque y la medición de variables forestales. Esta información podría suponer una drástica reducción de costes en la generación de información continua de alta resolución de inventario forestal. En el capítulo 2 se evalúa la estimación de variables forestales a partir de la información LiDAR capturada en el marco del Plan Nacional de Ortofotografía Aérea (PNOA-LiDAR) en España. Para ello se compara un vuelo específico diseñado para inventario forestal con la información de la misma zona capturada dentro del PNOA-LiDAR. El caso de estudio muestra cómo el ángulo de escaneo, la pendiente y orientación del terreno afectan de forma estadísticamente significativa, aunque con pequeñas diferencias, a la estimación de biomasa y variables de estructura forestal derivadas del LiDAR. La cobertura de copas resultó más afectada por estos factores que los percentiles de alturas. Considerando toda la zona de estudio, la estimación de la biomasa con ambas bases de datos no presentó diferencias estadísticamente significativas. Las simulaciones realizadas muestran que las diferencias medias en la estimación de biomasa entre un vuelo específico y el vuelo nacional podrán superar el 4% en áreas abruptas, con ángulos de escaneo altos y cuando la pendiente de la ladera no esté orientada hacia la línea de escaneo. En el capítulo 3 se desarrolla un estudio en masas mixtas y puras de pino silvestre y haya, con un enfoque multi-fuente empleando toda la información disponible (vuelos LiDAR nacionales de baja densidad de puntos, imágenes satelitales Landsat y parcelas permanentes del inventario forestal nacional español). Se concluye que este enfoque multi-fuente es adecuado para realizar inventarios forestales continuos de alta resolución en grandes superficies. Los errores obtenidos en la fase de ajuste y de validación de los modelos de área basimétrica y volumen son similares a los registrados por otros autores (usando un vuelo específico y parcelas de campo específicas). Se observan errores mayores en la variable número de pies que los encontrados en la literatura, que pueden ser explicados por la influencia de la metodología de parcelas de radio variable en esta variable. En los capítulos 4 y 5 se evalúan los métodos de masa para estimar biomasa y densidad de carbono en bosques tropicales. Para ello se trabaja con datos del Parque Nacional Volcán Poás (Costa Rica) en dos situaciones diferentes: i) se dispone de una cobertura completa LiDAR del área de estudio (capitulo 4) y ii) la cobertura LiDAR completa no es técnica o económicamente posible y se combina una cobertura incompleta de LiDAR con imágenes Landsat e información auxiliar para la estimación de biomasa y carbono (capitulo 5). En el capítulo 4 se valida un modelo LiDAR general de estimación de biomasa aérea en bosques tropicales y se compara con los resultados obtenidos con un modelo ajustado de forma específica para el área de estudio. Ambos modelos están basados en la variable altura media de copas (TCH por sus siglas en inglés) derivada del modelo digital LiDAR de altura de la vegetación. Los resultados en el área de estudio muestran que el modelo general es una alternativa fiable al ajuste de modelos específicos y que la biomasa aérea puede ser estimada en una nueva zona midiendo en campo únicamente la variable área basimétrica (BA). Para mejorar la aplicación de esta metodología es necesario definir en futuros trabajos procedimientos adecuados de medición de la variable área basimétrica en campo (localización, tamaño y forma de las parcelas de campo). La relación entre la altura media de copas del LiDAR y el área basimétrica (Coeficiente de Stock) obtenida en el área de estudio varía localmente. Por tanto es necesario contar con más información de campo para caracterizar la variabilidad del Coeficiente de Stock entre zonas de vida y si estrategias como la estratificación pueden reducir los errores en la estimación de biomasa y carbono en bosques tropicales. En el capítulo 5 se concluye que la combinación de una muestra sistemática de información LiDAR con una cobertura completa de imagen satelital de moderada resolución (e información auxiliar) es una alternativa efectiva para la realización de inventarios continuos en bosques tropicales. Esta metodología permite estimar altura de la vegetación, biomasa y carbono en grandes zonas donde la captura de una cobertura completa de LiDAR y la realización de un gran volumen de trabajo de campo es económica o/y técnicamente inviable. Las alternativas examinadas para la predicción de biomasa a partir de imágenes Landsat muestran una ligera disminución del coeficiente de determinación y un pequeño aumento del RMSE cuando la cobertura de LiDAR es reducida de forma considerable. Los resultados indican que la altura de la vegetación, la biomasa y la densidad de carbono pueden ser estimadas en bosques tropicales de forma adecuada usando coberturas de LIDAR bajas (entre el 5% y el 20% del área de estudio). ABSTRACT The availability of accurate and updated forest data is essential for improving sustainable forest management, promoting forest conservation policies and reducing carbon emissions from deforestation and forest degradation (REDD). In this sense, LiDAR technology proves to be a clear-cut tool for characterizing forest structure in large areas and assessing main forest-stand variables. Forest variables such as biomass, stem volume, basal area, mean diameter, mean height, dominant height, and stem number can be thus predicted with better or comparable quality than with costly traditional field inventories. In this thesis, it is analysed the potential of LiDAR technology for the estimation of plot-level forest variables under a range of conditions (conifer & broadleaf temperate forests and tropical forests) and different LiDAR capture characteristics (nationwide LiDAR information vs. specific forest LiDAR data). This study evaluates the application of LiDAR-based plot-level methods in large areas. These methods are based on statistical relationships between predictor variables (derived from airborne data) and field-measured variables to generate wall to wall forest inventories. The fast development of this technology in recent years has led to an increasing availability of national LiDAR datasets, usually developed for multiple purposes throughout an expanding number of countries and regions. The evaluation of the validity of nationwide LiDAR databases (not designed specifically for forest purposes) is needed and presents a great opportunity for substantially reducing the costs of forest inventories. In chapter 2, the suitability of Spanish nationwide LiDAR flight (PNOA) to estimate forest variables is analyzed and compared to a specifically forest designed LiDAR flight. This study case shows that scan angle, terrain slope and aspect significantly affect the assessment of most of the LiDAR-derived forest variables and biomass estimation. Especially, the estimation of canopy cover is more affected than height percentiles. Considering the entire study area, biomass estimations from both databases do not show significant differences. Simulations show that differences in biomass could be larger (more than 4%) only in particular situations, such as steep areas when the slopes are non-oriented towards the scan lines and the scan angles are larger than 15º. In chapter 3, a multi-source approach is developed, integrating available databases such as nationwide LiDAR flights, Landsat imagery and permanent field plots from SNFI, with good resultos in the generation of wall to wall forest inventories. Volume and basal area errors are similar to those obtained by other authors (using specific LiDAR flights and field plots) for the same species. Errors in the estimation of stem number are larger than literature values as a consequence of the great influence that variable-radius plots, as used in SNFI, have on this variable. In chapters 4 and 5 wall to wall plot-level methodologies to estimate aboveground biomass and carbon density in tropical forest are evaluated. The study area is located in the Poas Volcano National Park (Costa Rica) and two different situations are analyzed: i) available complete LiDAR coverage (chapter 4) and ii) a complete LiDAR coverage is not available and wall to wall estimation is carried out combining LiDAR, Landsat and ancillary data (chapter 5). In chapter 4, a general aboveground biomass plot-level LiDAR model for tropical forest (Asner & Mascaro, 2014) is validated and a specific model for the study area is fitted. Both LiDAR plot-level models are based on the top-of-canopy height (TCH) variable that is derived from the LiDAR digital canopy model. Results show that the pantropical plot-level LiDAR methodology is a reliable alternative to the development of specific models for tropical forests and thus, aboveground biomass in a new study area could be estimated by only measuring basal area (BA). Applying this methodology, the definition of precise BA field measurement procedures (e.g. location, size and shape of the field plots) is decisive to achieve reliable results in future studies. The relation between BA and TCH (Stocking Coefficient) obtained in our study area in Costa Rica varied locally. Therefore, more field work is needed for assessing Stocking Coefficient variations between different life zones and the influence of the stratification of the study areas in tropical forests on the reduction of uncertainty. In chapter 5, the combination of systematic LiDAR information sampling and full coverage Landsat imagery (and ancillary data) prove to be an effective alternative for forest inventories in tropical areas. This methodology allows estimating wall to wall vegetation height, biomass and carbon density in large areas where full LiDAR coverage and traditional field work are technically and/or economically unfeasible. Carbon density prediction using Landsat imaginery shows a slight decrease in the determination coefficient and an increase in RMSE when harshly decreasing LiDAR coverage area. Results indicate that feasible estimates of vegetation height, biomass and carbon density can be accomplished using low LiDAR coverage areas (between 5% and 20% of the total area) in tropical locations.

Fénix: a flexible information exchange data model for natural language processing

In this paper we describe Fénix, a data model for exchanging information between Natural Language Processing applications. The format proposed is intended to be flexible enough to cover both current and future data structures employed in the field of Computational Linguistics. The Fénix architecture is divided into four separate layers: conceptual, logical, persistence and physical. This division provides a simple interface to abstract the users from low-level implementation details, such as programming languages and data storage employed, allowing them to focus in the concepts and processes to be modelled. The Fénix architecture is accompanied by a set of programming libraries to facilitate the access and manipulation of the structures created in this framework. We will also show how this architecture has been already successfully applied in different research projects.

Deterministic mathematical morphology for CAD/CAM

Purpose – The purpose of this paper is to present a new geometric model based on the mathematical morphology paradigm, specialized to provide determinism to the classic morphological operations. The determinism is needed to model dynamic processes that require an order of application, as is the case for designing and manufacturing objects in CAD/CAM environments. Design/methodology/approach – The basic trajectory-based operation is the basis of the proposed morphological specialization. This operation allows the definition of morphological operators that obtain sequentially ordered sets of points from the boundary of the target objects, inexistent determinism in the classical morphological paradigm. From this basic operation, the complete set of morphological operators is redefined, incorporating the concept of boundary and determinism: trajectory-based erosion and dilation, and other morphological filtering operations. Findings – This new morphological framework allows the definition of complex three-dimensional objects, providing arithmetical support to generating machining trajectories, one of the most complex problems currently occurring in CAD/CAM. Originality/value – The model proposes the integration of the processes of design and manufacture, so that it avoids the problems of accuracy and integrity that present other classic geometric models that divide these processes in two phases. Furthermore, the morphological operative is based on points sets, so the geometric data structures and the operations are intrinsically simple and efficient. Another important value that no excessive computational resources are needed, because only the points in the boundary are processed.

Does the Common Agricultural Policy Reduce Farm Labour Migration? Panel data analysis across EU regions. Factor Markets Working Paper No. 28, July 2012

This paper deals with the determinants of labour out-migration from agriculture across 149 EU regions over the 1990–2008 period. The central aim is to shed light on the role played by payments from the common agricultural policy (CAP) on this important adjustment process. Using static and dynamic panel data estimators, we show that standard neoclassical drivers, like relative income and the relative labour share, represent significant determinants of the intersectoral migration of agricultural labour. Overall, CAP payments contributed significantly to job creation in agriculture, although the magnitude of the economic effect was rather moderate. We also find that pillar I subsidies exerted an effect approximately two times greater than that of pillar II payments.

Characterization of a distributed data base system /

Thesis--University of Illinois at Urbana-Champaign.

A PLATO lesson on information structures /

"UIUCDCS-R-74-615"