960 resultados para Televisió digital terrestre
Resumo:
In this paper we present the methodological procedures involved in the digital imaging in mesoscale of a block of travertines rock of quaternary age, originating from the city of Acquasanta, located in the Apennines, Italy. This rocky block, called T-Block, was stored in the courtyard of the Laboratório Experimental Petróleo "Kelsen Valente" (LabPetro), of Universidade Estadual de Campinas (UNICAMP), so that from it were performed Scientific studies, mainly for research groups universities and research centers working in brazilian areas of reservoir characterization and 3D digital imaging. The purpose of this work is the development of a Model Solid Digital, from the use of non-invasive techniques of digital 3D imaging of internal and external surfaces of the T-Block. For the imaging of the external surfaces technology has been used LIDAR (Light Detection and Range) and the imaging surface Interior was done using Ground Penetrating Radar (GPR), moreover, profiles were obtained with a Gamma Ray Gamae-spectômetro laptop. The goal of 3D digital imaging involved the identification and parameterization of surface geological and sedimentary facies that could represent heterogeneities depositional mesoscale, based on study of a block rocky with dimensions of approximately 1.60 m x 1.60 m x 2.70 m. The data acquired by means of terrestrial laser scanner made available georeferenced spatial information of the surface of the block (X, Y, Z), and varying the intensity values of the return laser beam and high resolution RGB data (3 mm x 3 mm), total points acquired 28,505,106. This information was used as an aid in the interpretation of radargrams and are ready to be displayed in rooms virtual reality. With the GPR was obtained 15 profiles of 2.3 m and 2 3D grids, each with 24 sections horizontal of 1.3 and 14 m vertical sections of 2.3 m, both the Antenna 900 MHz to about 2600 MHz antenna. Finally, the use of GPR associated with Laser Scanner enabled the identification and 3D mapping of 3 different radarfácies which were correlated with three sedimentary facies as had been defined at the outset. The 6 profiles showed gamma a low amplitude variation in the values of radioactivity. This is likely due to the fact of the sedimentary layers profiled have the same mineralogical composition, being composed by carbonate sediments, with no clay in siliciclastic pellitic layers or other mineral carrier elements radioactive
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Pós-graduação em Comunicação - FAAC
Resumo:
In Brazil, the discussion about thereplacement of analog television signals to digitaland its impact on society, in media companies andgovernment began in the 90s. Embryonic steps towardsdigitalisation of the television signal ground were thegovernment of Fernando Collor de Mello (1990-1992),with advances during the government of FernandoHenrique Cardoso (1994-2001) and in the governmentof Luiz Inacio Lula da Silva (2002). The academy startsthe discussion in 1996. This article aims to bring to lightthe results obtained from the survey Digital television:a historical perspective , which received the supportof CNPq for funding of two scholarships for scientifi cinitiation between August 2008 and July 2009. Theproject sought to identify what has been published onthe subject in the fi eld of Social Sciences and from threemacrodescritores (information management, publicpolicy and value chain), providing the li ing of a virtualcollection Zotero bibliographic innovative platform.The mapping serves to show the growing interest anddevelopment of research in the country during theperiod - when the number jumped to three works inthe fi rst seven years (1995-2001) to 198 in the last sevenyears (2002-2008). The research sought to identify themajor authors and works related to digital televisionand published in the country. The survey took intoaccount books, articles published in books, journals,Annals of Compós and Intercom, and dissertations andtheses. Data and refl ections on the survey are containedin this communication.
Resumo:
In questo elaborato, dopo una descrizione delle procedure per la creazione degli standard per il il broadcasting numerico adottate dal DVB forum, vengono presi in considerazione i trends del mercato del broadcasting numerico e analizzato in dettaglio lo standard utilizzato per la diffusione televisiva terrestre DVB-T e la sua evoluzione DVB-T2.
Resumo:
This thesis presents the outcomes of a Ph.D. course in telecommunications engineering. It is focused on the optimization of the physical layer of digital communication systems and it provides innovations for both multi- and single-carrier systems. For the former type we have first addressed the problem of the capacity in presence of several nuisances. Moreover, we have extended the concept of Single Frequency Network to the satellite scenario, and then we have introduced a novel concept in subcarrier data mapping, resulting in a very low PAPR of the OFDM signal. For single carrier systems we have proposed a method to optimize constellation design in presence of a strong distortion, such as the non linear distortion provided by satellites' on board high power amplifier, then we developed a method to calculate the bit/symbol error rate related to a given constellation, achieving an improved accuracy with respect to the traditional Union Bound with no additional complexity. Finally we have designed a low complexity SNR estimator, which saves one-half of multiplication with respect to the ML estimator, and it has similar estimation accuracy.
Resumo:
El objetivo de este Proyecto Fin de Carrera (PFC) es la obtención de un modelo tridimensional de “La Puerta de la Latina”, ubicada en el aparcamiento delantero de la Escuela Técnica Superior de Arquitectura de la Universidad Politécnica de Madrid. El levantamiento se realiza con el equipo láser escáner terrestre Riegl LMS-Z420i. Tras la toma de datos se efectuará el tratamiento de la nube de puntos y se obtendrá una “imagen realista” del modelo, entendiendo por “imagen realista”una representación final en la que, partiendo del modelo digital triangulado, se realiza una asignación de texturas a partir de imágenes obtenidas in situ. Este proyecto pretende ser un ensayo de las posibilidades de esta tecnología en el proceso de la representación tridimensional de edificios de interés arquitectónico e histórico.
Resumo:
Se está produciendo en la geodesia un cambio de paradigma en la concepción de los modelos digitales del terreno, pasando de diseñar el modelo con el menor número de puntos posibles a hacerlo con cientos de miles o millones de puntos. Este cambio ha sido consecuencia de la introducción de nuevas tecnologías como el escáner láser, la interferometría radar y el tratamiento de imágenes. La rápida aceptación de estas nuevas tecnologías se debe principalmente a la gran velocidad en la toma de datos, a la accesibilidad por no precisar de prisma y al alto grado de detalle de los modelos. Los métodos topográficos clásicos se basan en medidas discretas de puntos que considerados en su conjunto forman un modelo; su precisión se deriva de la precisión en la toma singular de estos puntos. La tecnología láser escáner terrestre (TLS) supone una aproximación diferente para la generación del modelo del objeto observado. Las nubes de puntos, producto del escaneo con TLS, pasan a ser tratadas en su conjunto mediante análisis de áreas, de forma que ahora el modelo final no es el resultado de una agregación de puntos sino la de la mejor superficie que se adapta a las nubes de puntos. Al comparar precisiones en la captura de puntos singulares realizados con métodos taquimétricos y equipos TLS la inferioridad de estos últimos es clara; sin embargo es en el tratamiento de las nubes de puntos, con los métodos de análisis basados en áreas, se han obtenido precisiones aceptables y se ha podido considerar plenamente la incorporación de esta tecnología en estudios de deformaciones y movimientos de estructuras. Entre las aplicaciones del TLS destacan las de registro del patrimonio, registro de las fases en la construcción de plantas industriales y estructuras, atestados de accidentes y monitorización de movimientos del terreno y deformaciones de estructuras. En la auscultación de presas, comparado con la monitorización de puntos concretos dentro, en coronación o en el paramento de la presa, disponer de un modelo continuo del paramento aguas abajo de la presa abre la posibilidad de introducir los métodos de análisis de deformaciones de superficies y la creación de modelos de comportamiento que mejoren la comprensión y previsión de sus movimientos. No obstante, la aplicación de la tecnología TLS en la auscultación de presas debe considerarse como un método complementario a los existentes. Mientras que los péndulos y la reciente técnica basada en el sistema de posicionamiento global diferencial (DGPS) dan una información continua de los movimientos de determinados puntos de la presa, el TLS permite ver la evolución estacional y detectar posibles zonas problemáticas en todo el paramento. En este trabajo se analizan las características de la tecnología TLS y los parámetros que intervienen en la precisión final de los escaneos. Se constata la necesidad de utilizar equipos basados en la medida directa del tiempo de vuelo, también llamados pulsados, para distancias entre 100 m y 300 m Se estudia la aplicación del TLS a la modelización de estructuras y paramentos verticales. Se analizan los factores que influyen en la precisión final, como el registro de nubes, tipo de dianas y el efecto conjunto del ángulo y la distancia de escaneo. Finalmente, se hace una comparación de los movimientos dados por los péndulos directos de una presa con los obtenidos del análisis de las nubes de puntos correspondientes a varias campañas de escaneos de la misma presa. Se propone y valida el empleo de gráficos patrón para relacionar las variables precisión o exactitud con los factores distancia y ángulo de escaneo en el diseño de trabajos de campo. Se expone su aplicación en la preparación del trabajo de campo para la realización de una campaña de escaneos dirigida al control de movimientos de una presa y se realizan recomendaciones para la aplicación de la técnica TLS a grandes estructuras. Se ha elaborado el gráfico patrón de un equipo TLS concreto de alcance medio. Para ello se hicieron dos ensayos de campo en condiciones reales de trabajo, realizando escaneos en todo el rango de distancias y ángulos de escaneo del equipo. Se analizan dos métodos para obtener la precisión en la modelización de paramentos y la detección de movimientos de estos: el método del “plano de mejor ajuste” y el método de la “deformación simulada”. Por último, se presentan los resultados de la comparación de los movimientos estacionales de una presa arco-gravedad entre los registrados con los péndulos directos y los obtenidos a partir de los escaneos realizados con un TLS. Los resultados muestran diferencias de milímetros, siendo el mejor de ellos del orden de un milímetro. Se explica la metodología utilizada y se hacen consideraciones respecto a la densidad de puntos de las nubes y al tamaño de las mallas de triángulos. A shift of paradigm in the conception of the survey digital models is taking place in geodesy, moving from designing a model with the fewer possible number of points to models of hundreds of thousand or million points. This change has happened because of the introduction of new technologies like the laser scanner, the interferometry radar and the processing of images. The fast acceptance of these new technologies has been due mainly to the great speed getting the data, to the accessibility as reflectorless technique, and to the high degree of detail of the models. Classic survey methods are based on discreet measures of points that, considered them as a whole, form a model; the precision of the model is then derived from the precision measuring the single points. The terrestrial laser scanner (TLS) technology supposes a different approach to the model generation of the observed object. Point cloud, the result of a TLS scan, must be treated as a whole, by means of area-based analysis; so, the final model is not an aggregation of points but the one resulting from the best surface that fits with the point cloud. Comparing precisions between the one resulting from the capture of singular points made with tachometric measurement methods and with TLS equipment, the inferiority of this last one is clear; but it is in the treatment of the point clouds, using area-based analysis methods, when acceptable precisions have been obtained and it has been possible to consider the incorporation of this technology for monitoring structures deformations. Among TLS applications it have to be emphasized those of registry of the cultural heritage, stages registry during construction of industrial plants and structures, police statement of accidents and monitorization of land movements and structures deformations. Compared with the classical dam monitoring, approach based on the registry of a set of points, the fact having a continuous model of the downstream face allows the possibility of introducing deformation analysis methods and behavior models that would improve the understanding and forecast of dam movements. However, the application of TLS technology for dam monitoring must be considered like a complementary method with the existing ones. Pendulums and recently the differential global positioning system (DGPS) give a continuous information of the movements of certain points of the dam, whereas TLS allows following its seasonal evolution and to detect damaged zones of the dam. A review of the TLS technology characteristics and the factors affecting the final precision of the scanning data is done. It is stated the need of selecting TLS based on the direct time of flight method, also called pulsed, for scanning distances between 100m and 300m. Modelling of structures and vertical walls is studied. Factors that influence in the final precision, like the registry of point clouds, target types, and the combined effect of scanning distance and angle of incidence are analyzed. Finally, a comparison among the movements given by the direct pendulums of a dam and the ones obtained from the analysis of point clouds is done. A new approach to obtain a complete map-type plot of the precisions of TLS equipment based on the direct measurement of time of flight method at midrange distances is presented. Test were developed in field-like conditions, similar to dam monitoring and other civil engineering works. Taking advantage of graphic semiological techniques, a “distance - angle of incidence” map based was designed and evaluated for field-like conditions. A map-type plot was designed combining isolines with sized and grey scale points, proportional to the precision values they represent. Precisions under different field conditions were compared with specifications. For this purpose, point clouds were evaluated under two approaches: the standar "plane-of-best-fit" and the proposed "simulated deformation”, that showed improved performance. These results lead to a discussion and recommendations about optimal TLS operation in civil engineering works. Finally, results of the comparison of seasonal movements of an arc-gravity dam between the registered by the direct pendulums ant the obtained from the TLS scans, are shown. The results show differences of millimeters, being the best around one millimeter. The used methodology is explained and considerations with respect to the point cloud density and to the size of triangular meshes are done.
Resumo:
Essa pesquisa discorre sobre possibilidades e entraves na aplicação do Sistema Brasileiro de Televisão Digital Interativa Terrestre (SBTVDI-T) nos Sistemas de Ensino a Distância (EAD) de nível superior. Justifica-se a importância da pesquisa pelas especulações que o nascimento do SBTVDI gera quanto a suas contribuições tecnológicas, algumas delas voltadas especificamente para o sistema de ensino. Objetiva-se coletar e analisar as possibilidades e impasses da nova tecnologia em relação a EAD de nível superior, considerando a visão dos profissionais envolvidos na implantação da nova TV brasileira. A metodologia da dissertação está composta de pesquisas documentais e bibliográficas que fundamentam a televisão digital brasileira, interatividade e EAD relacionadas com entrevistas em profundidade com os desenvolvedores e pesquisadores da nova tecnologia, sistematizadas pelo método da análise interpretativa. Concluí-se que TV digital pode ser aliada à EAD, independente do grau de ensino, mas ainda é inconclusiva sua participação específica na convergência entre as tecnologias da informação e da comunicação (TIC) disponíveis.
Resumo:
The objective of this Doctoral Thesis was monitoring, in trimestral scale, the coastal morphology of the Northeastern coast sections of Rio Grande do Norte State, in Brazil, which is an area of Potiguar Basin influenced by the oil industry activities. The studied sections compose coastal areas with intense sedimentary erosion and high environmental sensitivity to the oil spill. In order to achieve the general objective of this study, the work has been systematized in four steps. The first one refers to the evaluation of the geomorphological data acquisition methodologies used on Digital Elevation Model (DEM) of sandy beaches. The data has been obtained from Soledade beach, located on the Northeastern coast of Rio Grande Norte. The second step has been centered on the increasing of the reference geodetic infrastructure to accomplish the geodetic survey of the studied area by implanting a station in Corta Cachorro Barrier Island and by conducting monitoring geodetic surveys to understand the beach system based on the Coastline (CL) and on DEM multitemporal analysis. The third phase has been related to the usage of the methodology developed by Santos; Amaro (2011) and Santos et al. (2012) for the surveying, processing, representation, integration and analysis of Coastlines from sandy coast, which have been obtained through geodetic techniques of positioning, morphological change analysis and sediment transport. The fourth stage represents the innovation of surveys in coastal environment by using the Terrestrial Laser Scanning (TLS), based on Light Detection and Ranging (LiDAR), to evaluate a highly eroded section on Soledade beach where the oil industry structures are located. The evaluation has been achieved through high-precision DEM and accuracy during the modeling of the coast morphology changes. The result analysis of the integrated study about the spatial and temporal interrelations of the intense coastal processes in areas of building cycles and destruction of beaches has allowed identifying the causes and consequences of the intense coastal erosion in exposed beach sections and in barrier islands
Resumo:
Language is a unique aspect of human communication because it can be used to discuss itself in its own terms. For this reason, human societies potentially have superior capacities of co-ordination, reflexive self-correction, and innovation than other animal, physical or cybernetic systems. However, this analysis also reveals that language is interconnected with the economically and technologically mediated social sphere and hence is vulnerable to abstraction, objectification, reification, and therefore ideology – all of which are antithetical to its reflexive function, whilst paradoxically being a fundamental part of it. In particular, in capitalism, language is increasingly commodified within the social domains created and affected by ubiquitous communication technologies. The advent of the so-called ‘knowledge economy’ implicates exchangeable forms of thought (language) as the fundamental commodities of this emerging system. The historical point at which a ‘knowledge economy’ emerges, then, is the critical point at which thought itself becomes a commodified ‘thing’, and language becomes its “objective” means of exchange. However, the processes by which such commodification and objectification occurs obscures the unique social relations within which these language commodities are produced. The latest economic phase of capitalism – the knowledge economy – and the obfuscating trajectory which accompanies it, we argue, is destroying the reflexive capacity of language particularly through the process of commodification. This can be seen in that the language practices that have emerged in conjunction with digital technologies are increasingly non-reflexive and therefore less capable of self-critical, conscious change.