Towards a unified sentiment lexicon based on graphics processing units

This paper presents an approach to create what we have called a Unified Sentiment Lexicon (USL). This approach aims at aligning, unifying, and expanding the set of sentiment lexicons which are available on the web in order to increase their robustness of coverage. One problem related to the task of the automatic unification of different scores of sentiment lexicons is that there are multiple lexical entries for which the classification of positive, negative, or neutral {P, Z, N} depends on the unit of measurement used in the annotation methodology of the source sentiment lexicon. Our USL approach computes the unified strength of polarity of each lexical entry based on the Pearson correlation coefficient which measures how correlated lexical entries are with a value between 1 and -1, where 1 indicates that the lexical entries are perfectly correlated, 0 indicates no correlation, and -1 means they are perfectly inversely correlated and so is the UnifiedMetrics procedure for CPU and GPU, respectively. Another problem is the high processing time required for computing all the lexical entries in the unification task. Thus, the USL approach computes a subset of lexical entries in each of the 1344 GPU cores and uses parallel processing in order to unify 155802 lexical entries. The results of the analysis conducted using the USL approach show that the USL has 95.430 lexical entries, out of which there are 35.201 considered to be positive, 22.029 negative, and 38.200 neutral. Finally, the runtime was 10 minutes for 95.430 lexical entries; this allows a reduction of the time computing for the UnifiedMetrics by 3 times.

3D simulation of complex shading affecting PV systems taking benefit from the power of graphics cards developed for the video game industry

Shading reduces the power output of a photovoltaic (PV) system. The design engineering of PV systems requires modeling and evaluating shading losses. Some PV systems are affected by complex shading scenes whose resulting PV energy losses are very difficult to evaluate with current modeling tools. Several specialized PV design and simulation software include the possibility to evaluate shading losses. They generally possess a Graphical User Interface (GUI) through which the user can draw a 3D shading scene, and then evaluate its corresponding PV energy losses. The complexity of the objects that these tools can handle is relatively limited. We have created a software solution, 3DPV, which allows evaluating the energy losses induced by complex 3D scenes on PV generators. The 3D objects can be imported from specialized 3D modeling software or from a 3D object library. The shadows cast by this 3D scene on the PV generator are then directly evaluated from the Graphics Processing Unit (GPU). Thanks to the recent development of GPUs for the video game industry, the shadows can be evaluated with a very high spatial resolution that reaches well beyond the PV cell level, in very short calculation times. A PV simulation model then translates the geometrical shading into PV energy output losses. 3DPV has been implemented using WebGL, which allows it to run directly from a Web browser, without requiring any local installation from the user. This also allows taken full benefits from the information already available from Internet, such as the 3D object libraries. This contribution describes, step by step, the method that allows 3DPV to evaluate the PV energy losses caused by complex shading. We then illustrate the results of this methodology to several application cases that are encountered in the world of PV systems design. Keywords: 3D, modeling, simulation, GPU, shading, losses, shadow mapping, solar, photovoltaic, PV, WebGL

Parallel Computer Vision Algorithms for Graphics Processing Units

La evolución de los teléfonos móviles inteligentes, dotados de cámaras digitales, está provocando una creciente demanda de aplicaciones cada vez más complejas que necesitan algoritmos de visión artificial en tiempo real; puesto que el tamaño de las señales de vídeo no hace sino aumentar y en cambio el rendimiento de los procesadores de un solo núcleo se ha estancado, los nuevos algoritmos que se diseñen para visión artificial han de ser paralelos para poder ejecutarse en múltiples procesadores y ser computacionalmente escalables. Una de las clases de procesadores más interesantes en la actualidad se encuentra en las tarjetas gráficas (GPU), que son dispositivos que ofrecen un alto grado de paralelismo, un excelente rendimiento numérico y una creciente versatilidad, lo que los hace interesantes para llevar a cabo computación científica. En esta tesis se exploran dos aplicaciones de visión artificial que revisten una gran complejidad computacional y no pueden ser ejecutadas en tiempo real empleando procesadores tradicionales. En cambio, como se demuestra en esta tesis, la paralelización de las distintas subtareas y su implementación sobre una GPU arrojan los resultados deseados de ejecución con tasas de refresco interactivas. Asimismo, se propone una técnica para la evaluación rápida de funciones de complejidad arbitraria especialmente indicada para su uso en una GPU. En primer lugar se estudia la aplicación de técnicas de síntesis de imágenes virtuales a partir de únicamente dos cámaras lejanas y no paralelas—en contraste con la configuración habitual en TV 3D de cámaras cercanas y paralelas—con información de color y profundidad. Empleando filtros de mediana modificados para la elaboración de un mapa de profundidad virtual y proyecciones inversas, se comprueba que estas técnicas son adecuadas para una libre elección del punto de vista. Además, se demuestra que la codificación de la información de profundidad con respecto a un sistema de referencia global es sumamente perjudicial y debería ser evitada. Por otro lado se propone un sistema de detección de objetos móviles basado en técnicas de estimación de densidad con funciones locales. Este tipo de técnicas es muy adecuada para el modelado de escenas complejas con fondos multimodales, pero ha recibido poco uso debido a su gran complejidad computacional. El sistema propuesto, implementado en tiempo real sobre una GPU, incluye propuestas para la estimación dinámica de los anchos de banda de las funciones locales, actualización selectiva del modelo de fondo, actualización de la posición de las muestras de referencia del modelo de primer plano empleando un filtro de partículas multirregión y selección automática de regiones de interés para reducir el coste computacional. Los resultados, evaluados sobre diversas bases de datos y comparados con otros algoritmos del estado del arte, demuestran la gran versatilidad y calidad de la propuesta. Finalmente se propone un método para la aproximación de funciones arbitrarias empleando funciones continuas lineales a tramos, especialmente indicada para su implementación en una GPU mediante el uso de las unidades de filtraje de texturas, normalmente no utilizadas para cómputo numérico. La propuesta incluye un riguroso análisis matemático del error cometido en la aproximación en función del número de muestras empleadas, así como un método para la obtención de una partición cuasióptima del dominio de la función para minimizar el error. ABSTRACT The evolution of smartphones, all equipped with digital cameras, is driving a growing demand for ever more complex applications that need to rely on real-time computer vision algorithms. However, video signals are only increasing in size, whereas the performance of single-core processors has somewhat stagnated in the past few years. Consequently, new computer vision algorithms will need to be parallel to run on multiple processors and be computationally scalable. One of the most promising classes of processors nowadays can be found in graphics processing units (GPU). These are devices offering a high parallelism degree, excellent numerical performance and increasing versatility, which makes them interesting to run scientific computations. In this thesis, we explore two computer vision applications with a high computational complexity that precludes them from running in real time on traditional uniprocessors. However, we show that by parallelizing subtasks and implementing them on a GPU, both applications attain their goals of running at interactive frame rates. In addition, we propose a technique for fast evaluation of arbitrarily complex functions, specially designed for GPU implementation. First, we explore the application of depth-image–based rendering techniques to the unusual configuration of two convergent, wide baseline cameras, in contrast to the usual configuration used in 3D TV, which are narrow baseline, parallel cameras. By using a backward mapping approach with a depth inpainting scheme based on median filters, we show that these techniques are adequate for free viewpoint video applications. In addition, we show that referring depth information to a global reference system is ill-advised and should be avoided. Then, we propose a background subtraction system based on kernel density estimation techniques. These techniques are very adequate for modelling complex scenes featuring multimodal backgrounds, but have not been so popular due to their huge computational and memory complexity. The proposed system, implemented in real time on a GPU, features novel proposals for dynamic kernel bandwidth estimation for the background model, selective update of the background model, update of the position of reference samples of the foreground model using a multi-region particle filter, and automatic selection of regions of interest to reduce computational cost. The results, evaluated on several databases and compared to other state-of-the-art algorithms, demonstrate the high quality and versatility of our proposal. Finally, we propose a general method for the approximation of arbitrarily complex functions using continuous piecewise linear functions, specially formulated for GPU implementation by leveraging their texture filtering units, normally unused for numerical computation. Our proposal features a rigorous mathematical analysis of the approximation error in function of the number of samples, as well as a method to obtain a suboptimal partition of the domain of the function to minimize approximation error.

South America, 1807 (Image 2 of 7) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Colombia Prima or South America : in which it has been attempted to delineate the extent of our knowledge of that continent, extracted chiefly from the original manuscript maps of ... Pinto, likewise fom those of João Joaquin da Rocha, João da Costa Ferreira ... Francisco Manuel Sobreviela &c. and from the most authentic edited accounts of those countries, digested & constructed by ... Louis Stanislas D'Arcy Delarochette. It was published by William Faden geographer to His Majesty and to His Royal Highness the Prince of Wales in June 4th, 1807. Scale [ca. 1:3,000,000]. This layer is image 2 of 7 total images of the eight sheet map, representing the northern portion of the map.The image inside the map neatline is georeferenced to the surface of the earth and fit to the South America Lambert Conformal Conic projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, roads, territorial boundaries, shoreline features, mines, tribes, and more. Relief shown by hachures. Includes notes.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

South America, 1807 (Image 3 of 7) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Colombia Prima or South America : in which it has been attempted to delineate the extent of our knowledge of that continent, extracted chiefly from the original manuscript maps of ... Pinto, likewise fom those of João Joaquin da Rocha, João da Costa Ferreira ... Francisco Manuel Sobreviela &c. and from the most authentic edited accounts of those countries, digested & constructed by ... Louis Stanislas D'Arcy Delarochette. It was published by William Faden geographer to His Majesty and to His Royal Highness the Prince of Wales in June 4th, 1807. Scale [ca. 1:3,000,000]. This layer is image 3 of 7 total images of the eight sheet map, representing the eastern portion of the map.The image inside the map neatline is georeferenced to the surface of the earth and fit to the South America Lambert Conformal Conic projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, roads, territorial boundaries, shoreline features, mines, tribes, and more. Relief shown by hachures. Includes notes.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

South America, 1807 (Image 4 of 7) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Colombia Prima or South America : in which it has been attempted to delineate the extent of our knowledge of that continent, extracted chiefly from the original manuscript maps of ... Pinto, likewise fom those of João Joaquin da Rocha, João da Costa Ferreira ... Francisco Manuel Sobreviela &c. and from the most authentic edited accounts of those countries, digested & constructed by ... Louis Stanislas D'Arcy Delarochette. It was published by William Faden geographer to His Majesty and to His Royal Highness the Prince of Wales in June 4th, 1807. Scale [ca. 1:3,000,000]. This layer is image 4 of 7 total images of the eight sheet map, representing the northeast portion of the map.The image inside the map neatline is georeferenced to the surface of the earth and fit to the South America Lambert Conformal Conic projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, roads, territorial boundaries, shoreline features, mines, tribes, and more. Relief shown by hachures. Includes notes.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

South America, 1807 (Image 5 of 7) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Colombia Prima or South America : in which it has been attempted to delineate the extent of our knowledge of that continent, extracted chiefly from the original manuscript maps of ... Pinto, likewise fom those of João Joaquin da Rocha, João da Costa Ferreira ... Francisco Manuel Sobreviela &c. and from the most authentic edited accounts of those countries, digested & constructed by ... Louis Stanislas D'Arcy Delarochette. It was published by William Faden geographer to His Majesty and to His Royal Highness the Prince of Wales in June 4th, 1807. Scale [ca. 1:3,000,000]. This layer is image 5 of 7 total images of the eight sheet map, representing the southwest portion of the map.The image inside the map neatline is georeferenced to the surface of the earth and fit to the South America Lambert Conformal Conic projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, roads, territorial boundaries, shoreline features, mines, tribes, and more. Relief shown by hachures. Includes notes.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

South America, 1807 (Image 6 of 7) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Colombia Prima or South America : in which it has been attempted to delineate the extent of our knowledge of that continent, extracted chiefly from the original manuscript maps of ... Pinto, likewise fom those of João Joaquin da Rocha, João da Costa Ferreira ... Francisco Manuel Sobreviela &c. and from the most authentic edited accounts of those countries, digested & constructed by ... Louis Stanislas D'Arcy Delarochette. It was published by William Faden geographer to His Majesty and to His Royal Highness the Prince of Wales in June 4th, 1807. Scale [ca. 1:3,000,000]. This layer is image 6 of 7 total images of the eight sheet map, representing the western portion of the map.The image inside the map neatline is georeferenced to the surface of the earth and fit to the South America Lambert Conformal Conic projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, roads, territorial boundaries, shoreline features, mines, tribes, and more. Relief shown by hachures. Includes notes.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

South America, 1807 (Image 7 of 7) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Colombia Prima or South America : in which it has been attempted to delineate the extent of our knowledge of that continent, extracted chiefly from the original manuscript maps of ... Pinto, likewise fom those of João Joaquin da Rocha, João da Costa Ferreira ... Francisco Manuel Sobreviela &c. and from the most authentic edited accounts of those countries, digested & constructed by ... Louis Stanislas D'Arcy Delarochette. It was published by William Faden geographer to His Majesty and to His Royal Highness the Prince of Wales in June 4th, 1807. Scale [ca. 1:3,000,000]. This layer is image 7 of 7 total images of the eight sheet map, representing the southern portion of the map.The image inside the map neatline is georeferenced to the surface of the earth and fit to the South America Lambert Conformal Conic projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, roads, territorial boundaries, shoreline features, mines, tribes, and more. Relief shown by hachures. Includes notes.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

South America, 1819 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: South America : from the latest Spanish and Portuguese surveys. It was published by W. Faden in Jany. 1, 1819. Scale [ca. 1:77,500,000]. The image inside the map neatline is georeferenced to the surface of the earth and fit to the South America Lambert Conformal Conic projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial boundaries, shoreline features, and more. Relief shown by hachures and pictorially.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

South America, 1825 (Image 1 of 2) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: General-Charte von Süd-America = Carte générale de L'Amerique Méridionale : en deux grandes feuilles. d'après les observations et les cartes spéciales, rapportées du Voyage dans l'intérieur du Brèsil, pendant les années 1817-1820..., par les Docteurs de Spix et de Martius, Chevaliers de L'Ordre civil de la Couronne de Bavière, membres de L'Académie Royale de Munich ; gestochen von Joh. Bapt. Seitz, Kupferstecher im topographischen Bureau des Kön. baier. General-Quartiermeister Stab. It was published by [M. Lindauer] in 1825. Scale [ca. 1:7,000,000]. This layer is image 1 of 2 total images of the two sheet source map, representing the southern portion of the map. Map in German and French. The image inside the map neatline is georeferenced to the surface of the earth and fit to the South America Lambert Conformal Conic projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial boundaries, roads, shoreline features, and more. Relief shown by hachures.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

South America, 1825 (Image 2 of 2) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: General-Charte von Süd-America = Carte générale de L'Amerique Méridionale : en deux grandes feuilles. d'après les observations et les cartes spéciales, rapportées du Voyage dans l'intérieur du Brèsil, pendant les années 1817-1820..., par les Docteurs de Spix et de Martius, Chevaliers de L'Ordre civil de la Couronne de Bavière, membres de L'Académie Royale de Munich ; gestochen von Joh. Bapt. Seitz, Kupferstecher im topographischen Bureau des Kön. baier. General-Quartiermeister Stab. It was published by [M. Lindauer] in 1825. Scale [ca. 1:7,000,000]. This layer is image 2 of 2 total images of the two sheet source map, representing the northern portion of the map. Map in German and French.The image inside the map neatline is georeferenced to the surface of the earth and fit to the South America Lambert Conformal Conic projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial boundaries, roads, shoreline features, and more. Relief shown by hachures.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.