3,363 research outputs found

    Achieving Identity-based cryptography in a personal digital assistant

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    Continuous technological advances have allowed that mobile devices, such as Personal Digital Assistants (PDAs), can execute sophisticated applications that more often than not must be equipped with a layer of security that should include the confidentiality and the authentication services within its repertory. Nevertheless, when compared against front-end computing devices, most PDAs are still seen as constrained devices with limited processing and storage capabilities. In order to achieve Identity-Based Cryptography (IBC), which was an open problem proposed by Adi Shamir in 1984, Boneh and Franklin presented in Crypto 2001, a solution that uses bilinear pairings as its main building block. Since then, IBC has become an active area of investigation where many efficient IBC security protocols are proposed year after year. In this paper, we present a cryptographic application that allows the secure exchange of documents from a Personal Digital Assistant (PDA) that is wirelessly connected to other nodes. The architecture of our application is inspired by the traditional PGP (Pretty Good Privacy) email security protocol. Our application achieves identity-based authentication and confidentiality functionalities at the 80-bit security level through the usage of a cryptographic library that was coded in C++. Our library can perform basic primitives such as bilinear pairings defined over the binary field and the ternary field , as well as other required primitives known as map-to-point hash functions. We report the timings achieved by our application and we show that they compare well against other similar works published in the open literature

    Heavy metals in water and stream sediments from the Auriferous District of Ginebra, Colombian Andes

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    Se determinaron concentraciones de metales pesados tóxicos en aguas, sedimentos de corriente y sedimentos en suspensión del Distrito Aurífero de Ginebra, un área minera de pequeña escala en el Departamento de Valle del Cauca (Colombia), mediante técnicas de espectrometría de absorción atómica. Los datos mostraron anomalías positivas relacionadas con las colas de mina, cuyas concentraciones decayeron hasta por debajo de los límites máximos permitidos para agua potable, como resultado de un efecto buffer del agua natural del área de estudio. Sin embargo, se debe considerar el riesgo potencial de polución severa aguas abajo, así como la introducción de metales pesados tóxicos en la cadena alimenticia, por contaminación de aguas y productos agrícolas. También se presentan algunas recomendaciones

    Reconstructing Secondary Data based on Air Quality, Meteorological and Traffic Data Considering Spatiotemporal Components

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    This paper introduces the reconstructed dataset along with procedures to implement air quality prediction, which consists of air quality, meteorological and traffic data over time, and their monitoring stations and measurement points. Given the fact that those monitoring stations and measurement points are located in different places, it is important to incorporate their time series data into a spatiotemporal dimension. The output can be used as input for various predictive analyses, in particular, we used the reconstructed dataset as input for grid-based (Convolutional Long Short-Term Memory and Bidirectional Convolutional Long Short-Term Memory) and graph-based (Attention Temporal Graph Convolutional Network) machine learning algorithms. The raw dataset is obtained from the Open Data portal of the Madrid City Council

    Late Cretaceous uplift in the Malargüe fold-and-thrust belt (35°S), Southern Central Andes of Argentina and Chile

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    The Cordillera de los Andes is the typical example of a subduction-related orogen. Its present topography is the result of post-Miocene uplift, however, Andean compressional deformation and uplift started in the Late Cretaceous, as increasingly recognized in different sectors of the mountain belt. We present evidences of a Late Cretaceous event of compressional deformation in the southern Central Andes (35ºS), reflected in syn-orogenic foreland basin deposits assigned to the Neuquén Group in Argentina and the Brownish-Red Clastic Unit in Chile. Comparison of the facies of these units allows us to recognize a sector proximal to the Late Cretaceous orogenic front, a distal sector with sediment provenance from the forebulge and a western sector where the sediments where deposited within the Late Cretaceous mountain belt. On this basis, we assign the orogenic front to an inverted Jurassic normal fault, the Río del Cobre fault, and reconstruct the structure of the easternmost Late Cretaceous Andes at this latitude. The change in the location of the orogenic front north and south of 35ºS allows us to recognize a long-lived change in behavior in Andean evolution in this sector, which correlates with a change in the shape and the deposits of Mesozoic Neuquén basin.Levantamiento Cretácico Tardío en la faja plegada y corrida de Malargüe (35oS), Andes Centrales del sur, Argentina y Chile. La Cordillera de los Andes es el ejemplo típico de un orógeno asociado a subducción. Si bien su topografía actual es el resultado del levantamiento posterior al Mioceno, la deformación y el levantamiento ándicos comenzaron a partir del Cretácico Tardío, como se reconoce actualmente en diversos sectores de la faja montañosa. En este trabajo se presentan evidencias de un evento de deformación compresiva durante el Cretácico Tardío en los Andes Centrales del sur (35oS) reconocido a partir de los depósitos sinorogénicos asociados, que se asignan al Grupo Neuquén en Argentina y la ʻUnidad Clástica Café-Rojiza’ (BRCU) en Chile. Mediante las variaciones de facies en estos depósitos se pueden reconocer un sector proximal cercano al frente orogénico Cretácico Tardío, un sector distal con aporte desde el dorso periférico, y un sector occidental en el que los depósitos se produjeron dentro del cordón montañoso. De esta manera, se puede ubicar el frente orogénico Cretácico Tardío, el que asignamos a la inversión tectónica de una falla normal jurásica, la falla Río del Cobre. El cambio en la ubicación del frente orogénico Cretácico al norte y sur de 35oS permite reconocer a este sector como un límite entre sectores con diferencias en su evolución andina, que se interpreta como heredado de la evolución de la cuenca Neuquina.Fil: Mescua, Jose Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina;Fil: Giambiagi, Laura Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina;Fil: Ramos, Victor Alberto. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología. Laboratorio de Tectónica Andina; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

    Influence of pre-Andean history over Andean foreland deformation: structural styles in the Malargüe fold-and-thrust belt at 35ºS, Andes of Argentina

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    We present the first complete balanced cross-section of the Argentinean Andes at 35ºS. Based on an extensive field survey and limited sub-surface information, we constructed a structural model in which both the tectonic inversion of Mesozoic normal faults and the formation of Cenozoic Andean thrusts play a role in the deformation. We obtained a shortening of 26.2 km, equivalent to 22% of the initial length. This value is lower than previous estimates obtained from partial cross-sections using non-inversion structural models. Comparison of our results with a geophysical model of the crust indicates that: (i) crustal thickness was not constant across the orogen before Andean shortening, but a thick (~45 km) crustal block was interpreted? in the west as a remnant of a Late Paleozoic orogeny, and a thinner sector (~32 km) was located in the east as a result of Mesozoic stretching; and (ii) the structural model presented in this work is more consistent with the regional shortening and crustal thickness trends than models which do not take into account tectonic inversion.Fil: Mescua, Jose Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Giambiagi, Laura Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Tassara Oddo, Andres Humberto. Universidad de Concepción; ChileFil: Gimenez, Mario Ernesto. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ramos, Victor Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

    The Andean movements of Groeber and the tectonic evolution of the southern Central Andes

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    Uno de los aportes más significativos de Pablo Groeber al conocimiento de los Andes fue su estudio de los movimientos tectónicos asociados al levantamiento de la cordillera. Los datos recogidos por Groeber en más de 40 años de trabajos de campo en los Andes de Neuquén, Mendoza y San Juan fueron sistematizados en un esquema de la evolución andina basado en el concepto de ?fases tectónicas? siguiendo en esa época las ideas dominantes de Stille. En este trabajo se analizan las propuestas realizadas por Groeber en función del conocimiento actual. Una lectura atenta de los trabajos de Groeber permite observar que era consciente de las limitaciones del método que utilizaba, debidas a la dificultad para establecer la edad de las unidades y al enfoque litoestratigráfico con él que intentó correlacionar las unidades abarcando áreas lejanas entre sí. Aún con estas limitaciones, pudo identificar la naturaleza episódica de esos levantamientos en sucesivas fases, que marcó un gran avance y constituyó la base para el progreso del conocimiento actual de la evolución tectónica de los Andes Centrales del Sur. La base de datos actual permite descartar la hipótesis simplista que asignaba a una fase diastrófica determinada una edad específica, reconociendo una serie no coetánea de deformaciones episódicas como responsable del levantamiento de los Andes, como lo vislumbrara Groeber con sus cuatro movimientos andinos con sus respectivas fases de diferente intensidad.The Andean movements of Groeber and the tectonic evolution of the southern Central Andes One of Pablo Groeber's most significant contributions to the knowledge of the Andes was his study of the tectonic movements associated with the uplift of the Andean Cordillera. The data collected by Groeber in more than 40 years of fieldwork in the Andes of Neuquén, Mendoza and San Juan were systematized in a scheme of Andean evolution based on the concept of "tectonic phases" following at that time the dominant ideas of Stille. In this paper we analyze the proposals made by Groeber based on our current knowledge. A careful reading of Groeber's work shows that he was aware of the limitations of the method he used, due to the difficulty in establishing the age of the units, and the lithostratigraphic approach with which he tried to correlate the units exposed in distant areas. Even with these limitations, he was able to identify the episodic nature of these uplifts in successive phases, which marked a great advance and constituted the basis for the progress of the current knowledge of the tectonic evolution of the southern Central Andes. The present database allows us to discard the simplistic hypothesis that assigned a specific age to a diastrophic phase, recognizing a non-coeval series of episodic deformations as responsible for the uplift of the Andes, as Groeber anticipated with his four Andean movements with their respective phases of different intensity.Fil: Mescua, Jose Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Giambiagi, Laura Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Ramos, Victor Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

    Uma análise empírica do impacto do balanced scorecard no desempenho de organizações Brasileiras

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    T35: a small automatic telescope for long-term observing campaigns

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    The T35 is a small telescope (14") equipped with a large format CCD camera installed in the Sierra Nevada Observatory (SNO) in Southern Spain. This telescope will be a useful tool for the detecting and studying pulsating stars, particularly, in open clusters. In this paper, we describe the automation process of the T35 and show also some images taken with the new instrumentation.Comment: 13 pages, 9 figures. Accepted for publication in the special issue "Robotic Astronomy" of Advances of Astronom

    Distributed robotic architecture based on smart services

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    This paper presents an approach for designing robots and robotic systems based on the application of models, architectures, techniques and tools that have contributed valid solutions in other areas, such as e-business. Before applying these solutions, the physical elements that make up a robotic system are subjected to a normalization process in order to characterize their functional contributions. In this way, the conceptual model and the technical architecture of the service-oriented architecture robotic system is established. The paper also includes a simple implementation enabling the proposal to be validated, together with the main conclusions reached and future lines of study
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