844 resultados para geographical location
Resumo:
Accurate data of the natural conditions and agricultural systems with a good spatial resolution are a key factor to tackle food insecurity in developing countries. A broad variety of approaches exists to achieve precise data and information about agriculture. One system, especially developed for smallholder agriculture in East Africa, is the Farm Management Handbook of Kenya. It was first published in 1982/83 and fully revised in 2012, now containing 7 volumes. The handbooks contain detailed information on climate, soils, suitable crops and soil care based on scientific research results of the last 30 years. The density of facts leads to time consuming extraction of all necessary information. In this study we analyse the user needs and necessary components of a system for decision support for smallholder farming in Kenya based on a geographical information system (GIS). Required data sources were identified, as well as essential functions of the system. We analysed the results of our survey conducted in 2012 and early 2013 among agricultural officers. The monitoring of user needs and the problem of non-adaptability of an agricultural information system on the level of extension officers in Kenya are the central objectives. The outcomes of the survey suggest the establishment of a decision support tool based on already available open source GIS components. The system should include functionalities to show general information for a specific location and should provide precise recommendations about suitable crops and management options to support agricultural guidance on farm level.
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We present a low cost and easily deployed infrastructure for location aware computing that is built using standard Bluetooth® technologies and personal computers. Mobile devices are able to determine their location to room-level granularity with existing bluetooth technology, and to even greater resolution with the use of the recently adopted bluetooth 1.2 specification, all while maintaining complete anonymity. Various techniques for improving the speed and resolution of the system are described, along with their tradeoffs in privacy. The system is trivial to implement on a large scale – our network covering 5,000 square meters was deployed by a single student over the course of a few days at a cost of less than US$1,000.
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SAGA (System for Automated Geographic Analysis) es un SIG libre con capacidades para el manejo y análisis de información tanto vectorial como ráster, con un especial enfoque en esta última. Asimismo, es su enfoque analítico el que constituye su característica más destacable, siendo una herramienta de primer orden para la extracción de información a partir de todo tipo de capas de datos georeferenciados. (...)
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This paper presents and compares two approaches to estimate the origin (upstream or downstream) of voltage sag registered in distribution substations. The first approach is based on the application of a single rule dealing with features extracted from the impedances during the fault whereas the second method exploit the variability of waveforms from an statistical point of view. Both approaches have been tested with voltage sags registered in distribution substations and advantages, drawbacks and comparative results are presented
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This paper focus on the problem of locating single-phase faults in mixed distribution electric systems, with overhead lines and underground cables, using voltage and current measurements at the sending-end and sequence model of the network. Since calculating series impedance for underground cables is not as simple as in the case of overhead lines, the paper proposes a methodology to obtain an estimation of zero-sequence impedance of underground cables starting from previous single-faults occurred in the system, in which an electric arc occurred at the fault location. For this reason, the signal is previously pretreated to eliminate its peaks voltage and the analysis can be done working with a signal as close as a sinus wave as possible
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Fault location has been studied deeply for transmission lines due to its importance in power systems. Nowadays the problem of fault location on distribution systems is receiving special attention mainly because of the power quality regulations. In this context, this paper presents an application software developed in Matlabtrade that automatically calculates the location of a fault in a distribution power system, starting from voltages and currents measured at the line terminal and the model of the distribution power system data. The application is based on a N-ary tree structure, which is suitable to be used in this application due to the highly branched and the non- homogeneity nature of the distribution systems, and has been developed for single-phase, two-phase, two-phase-to-ground, and three-phase faults. The implemented application is tested by using fault data in a real electrical distribution power system
Resumo:
The work presented in this paper belongs to the power quality knowledge area and deals with the voltage sags in power transmission and distribution systems. Propagating throughout the power network, voltage sags can cause plenty of problems for domestic and industrial loads that can financially cost a lot. To impose penalties to responsible party and to improve monitoring and mitigation strategies, sags must be located in the power network. With such a worthwhile objective, this paper comes up with a new method for associating a sag waveform with its origin in transmission and distribution networks. It solves this problem through developing hybrid methods which hire multiway principal component analysis (MPCA) as a dimension reduction tool. MPCA reexpresses sag waveforms in a new subspace just in a few scores. We train some well-known classifiers with these scores and exploit them for classification of future sags. The capabilities of the proposed method for dimension reduction and classification are examined using the real data gathered from three substations in Catalonia, Spain. The obtained classification rates certify the goodness and powerfulness of the developed hybrid methods as brand-new tools for sag classification
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Background: Multi-drug resistance and severe/ complicated cases are the emerging phenotypes of vivax malaria, which may deteriorate current anti-malarial control measures. The emergence of these phenotypes could be associated with either of the two Plasmodium vivax lineages. The two lineages had been categorized as Old World and New World, based on geographical sub-division and genetic and phenotypical markers. This study revisited the lineage hypothesis of P. vivax by typing the distribution of lineages among global isolates and evaluated their genetic relatedness using a panel of new mini-satellite markers. Methods: 18S SSU rRNA S-type gene was amplified from 420 Plasmodium vivax field isolates collected from different geographical regions of India, Thailand and Colombia as well as four strains each of P. vivax originating from Nicaragua, Panama, Thailand (Pak Chang), and Vietnam (ONG). A mini-satellite marker panel was then developed to understand the population genetic parameters and tested on a sample subset of both lineages. Results: 18S SSU rRNA S-type gene typing revealed the distribution of both lineages (Old World and New World) in all geographical regions. However, distribution of Plasmodium vivax lineages was highly variable in every geographical region. The lack of geographical sub-division between lineages suggests that both lineages are globally distributed. Ten mini-satellites were scanned from the P. vivax genome sequence; these tandem repeats were located in eight of the chromosomes. Mini-satellites revealed substantial allelic diversity (7-21, AE = 14.6 +/- 2.0) and heterozygosity (He = 0.697-0.924, AE = 0.857 +/- 0.033) per locus. Mini-satellite comparison between the two lineages revealed high but similar pattern of genetic diversity, allele frequency, and high degree of allele sharing. A Neighbour-Joining phylogenetic tree derived from genetic distance data obtained from ten mini-satellites also placed both lineages together in every cluster. Conclusions: The global lineage distribution, lack of genetic distance, similar pattern of genetic diversity, and allele sharing strongly suggested that both lineages are a single species and thus new emerging phenotypes associated with vivax malaria could not be clearly classified as belonging to a particular lineage on basis of their geographical origin.
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Este estudio busca mostrar la utilidad del modelado basado en agentes (MbA) para estudiar diferentes fenómenos sociales. Dicha herramienta economiza tiempo y recursos, permitiendo analizar muchas variables para posteriormente seleccionar las más significativas y proseguir así con la investigación. Lo anterior se ilustra con un modelo que analiza el tiempo requerido para encontrar y atender enfermos según sea su tratamiento: domiciliario u hospitalario, si el personal puede compartir o no información sobre localización de enfermos y si estos residen densamente o no. Los resultados revelan que compartir información acorta significativamente el tiempo sólo para tratamientos hospitalarios y que la densidad no tiene impacto. Concluimos que MbA tiene grandes ventajas para el diseño de investigaciones sociales y asiste a la toma de decisiones en contextos profesionales.
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Estudio de caso que busca evaluar el uso del gas natural dentro de la política exterior rusa como recurso estratégico en las relaciones con Ucrania. Se describe y analiza cómo la importancia geoestratégica de Ucrania genera una percepción de seguridad y relevancia económica en Rusia, por esta razón la Federación utiliza el gas natural como mecanismo de presión frente al Estado ucraniano para satisfacer sus intereses nacionales en función de los elementos mencionados anteriormente.Todo lo anterior a través de la Teoría del Heartland desarrollada por Halford Mackinder y El Concepto de Área Pivote de Zbigniew Brzezinski para determinar cómo se genera la importancia del Estado ucraniano frente a Rusia
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El trabajo de perfil de importaciones de Canadá desde Colombia fue un trabajo realizado con el objetivo de ser una guía para los empresarios tanto canadienses como colombianos para tener una idea clara de los principales productos importados y exportados de estos dos países, así mismo de los proveedores más importantes de cada uno de estos productos. El trabajo en un principio expone un marco teórico de que se debe tener en cuenta para exportar e importar productos o servicios desde un país a otro. Seguidamente se puede encontrar información general de Canadá y de todas sus provincias incluyendo descripción económica, logística y geográfica. Igualmente incluye información acerca de los principales productos exportados del mundo hacia cada provincia y los principales competidores. En la segunda parte, se provee información de los productos exportados con sus respectivos competidores hacia Canadá desde cada uno de los departamentos de Colombia. Y finalmente se muestran algunas recomendaciones y conclusiones acerca del trabajo anteriormente realizado.
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Proporciona los contenidos y prácticas necesarios para el examen de General Certificate Secondary Education (GCSE) realizado por el organismo Edexcel para el año 2009. Permite a los alumnos conocer y comprender el mundo en el que viven, realizar trabajos prácticos fuera del aula y desarrollar habilidades geográficas, aprender a trabajar en equipo y aprender mediante la investigación. Tiene como material de apoyo el recurso para el profesor.
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Geographical distribution, habitat and reproductive phenology of the Genus Kallymenia (Gigartinales, Rhodophyta) from Catalonia, Spain
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Los Centros de Investigación de Geografía son por lo general productores de un gran volumen de Información Geográfica (IG), los cuales generan tanto proyectos financiados como iniciativas de investigación individuales. El Centro de Estudos de Geografia e Planeamento Regional (e-GEO) ha estado involucrado en varios proyectos a escala local, regional, nacional e internacional. Recientemente, dos cuestiones fueron objeto de debate. Una de ellas fue el hecho de que la información espacial obtenida a partir del desarrollo de tales proyectos de investigación no ha tenido la visibilidad que se esperaba. En la mayoría de las veces, la IG de estos proyectos no estaba en el formato adecuado para que los investigadores -o incluso el público en general o grupos de interés- pudieran pesquisar fácilmente. La segunda cuestión era sobre cómo hacer que estos resultados pudieran ser accesibles al alcance de todos, en todos los lugares, fácilmente y con los mínimos costes para el Centro, teniendo en cuenta el actual contexto económico portugués y los intereses de e-GEO. Estas dos cuestiones se resuelven con una sola respuesta: la puesta en marcha de un WebGIS en una plataforma Open Source. En este trabajo se ilustra la producción de un instrumento para la difusión de las indicaciones geográficas en el World Wide Web, utilizando únicamente software libre y freeware. Esta herramienta permite a todos los investigadores del Centro publicar su IG, la cual aparece como plenamente accesible a cualquier usuario final. Potencialmente, el hecho de permitir que este tipo de información sea plenamente accesible debería generar un gran impacto, acortando las distancias entre el trabajo realizado por los académicos y el usuario final. Creemos que es una óptima manera para que el público pueda acceder e interpretar la información espacial. En conclusión, esta plataforma debería servir para cerrar la brecha entre productores y usuarios de la información geográfica, permitiendo la interacción entre todas las partes así como la carga de nuevos datos dado un conjunto de normas destinadas a control de calidad