Search results for "INFORMATION"
showing 10 items of 14916 documents
A Nonisovelocity Geometry-Based Underwater Acoustic Channel Model
2018
This paper proposes a new geometry-based shallow underwater acoustic (UWA) channel model allowing for nonisovelocity ocean conditions. The fact that the isovelocity assumption does not hold in many real-world scenarios motivates the need for developing channel models for nonisovelocity UWA propagation environments. Starting from a geometrical model, we develop a stochastic channel model for a single-input single-output (SISO) vehicle-to-vehicle UWA channel assuming that the ocean surface and bottom are rough and that the speed of sound varies with depth. The effect of the nonisovelocity condition has been assessed regarding its influence on the temporal autocorrelation function, the frequen…
Performance analysis of Alamouti-coded OFDM systems over spatio-temporally correlated underwater acoustic channels
2017
In this paper, we analyze the performance of Alamouti-coded orthogonal frequency division multiplexing (OFDM) systems over time-varying underwater acoustic (UWA) channels. A realistic UWA channel model has been considered, which can be correlated in either time or space or simultaneously in both domains. An exact analytical expression for the bit error probability (BEP) is necessary to analyze accurately the performance of Alamouti-coded OFDM systems over the spatio-temporally correlated UWA channel model. Hence, by using this UWA channel model, an expression has been derived for the BEP of Alamouti-coded OFDM systems assuming that the receiver knows perfectly the channel state information.…
Entorno 3D para el análisis y la recreación virtual de las actuaciones arqueológicas en Cueva de la Cocina (Dos Aguas, Valencia, España)
2017
Con este trabajo pretendemos presentar nuestro procedimiento de digitalización de información de campo (gestión de datos) y su imbricación en la reconstrucción estratigráfica virtual (virtualización) de la Cueva de la Cocina (Dos Aguas, Valencia, España). La herramienta principal para la implementación del Sistema de Información Geográfica (SIG) ha sido OpenJUMP, mientras que para la recreación tridimensional (3D) del entorno virtual de la cueva se han utilizado MeshLab, ParaView, CloudCompare y R. De acuerdo con los datos recuperados durante las excavaciones de los últimos años en la cueva -2015 y 2016-, se presenta el estado actual de la virtualización de la estratigrafía en los sectores …
Improving the accuracy of small vertebrate-based palaeoclimatic reconstructions derived from the Mutual Ecogeographic Range. A case study using geogr…
2019
Abstract Understanding past climate and the mechanisms of climate change remain major challenges in scientific research. The Mutual Ecogeographic Range (MER) method for climatic reconstruction uses the current geographical distribution of fossil assemblages to infer palaeoclimatic conditions. Current species distributions used in the MER method are usually obtained from biogeographic atlases that record the absence/presence of species in a 10 × 10 km grid. A 10 × 10 km area is quite broad and the method only records presence/absence, without considering the real area occupied by any given species. Thus, the method overlooks the fact that environmental heterogeneity is strongly related to to…
Tracking archaeological and historical mines using mineral prospectivity mapping.
2014
13 pages; International audience; The present study proposes a technological transfer from modern mining prospection to the field of archaeology, providing a methodology to facilitate the discovery of ancient mining sites. This method takes advantage of the thousands of geochemical analyses of streambed sediments, performed by national geological surveys to inventory mineral substances. In order to delineate geochemical anomalies, the datasets are treated following two different approaches: Exploratory Data Analysis and a fractal-based method often recognised as more powerful. Mineral prospectivity maps are then obtained by combining the results with a geographical information system. The s…
Current Wildland Fire Patterns and Challenges in Europe: A Synthesis of National Perspectives
2021
Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-scale wildland fire statistics across European countries, there is still a crucial need to collect and summarize in-depth local analysis and understanding of the wildland fire condition and associated challenges across Europe. This article aims to provide a general overview of the current wildland fire patterns and challenges as perceived by natio…
Linking theories, past practices, and archaeological remains of movement through ontological reasoning
2020
The amount of information available to archaeologists has grown dramatically during the last ten years. The rapid acquisition of observational data and creation of digital data has played a significant role in this &ldquo
Imidazolium Based Ionic Liquids: A Promising Green Solvent for Water Hyacinth Biomass Deconstruction.
2018
Water hyacinth (WH) is a troublesome aquatic weed of natural and artificial water bodies of India and other tropical countries and causing severe ecological problems. The WH biomass is low in lignin content and contains high amount of cellulose and hemicellulose, making it suitable material for conversion into liquid fuels for energy production. This study highlighted that, how different imidazolium based ionic liquids (ILs) [1-alkyl-3-methylimidazolium bromide, [Cnmim]Br (n = 2, 4, 6, 8, and 10)] with tunable properties can be employed for the degradation of WH biomass. Different characterizations techniques, such as XRD, FT-IR, SEM, and DSC are used to unravel the interplay between ILs an…
Interaction Capabilities of a Robotic Receptionist
2017
A system aimed at facilitating the interaction between a human user and an humanoid robot is presented. The system is suited to answer questions about laboratories activities, people involved, projects, research themes and collaborations among employees. The task is accomplished by the HermiT reasoner invoked by a speech recognition module. The system is capable of navigating a specific ontology making inference on it. The presented system is part of a broader social robot framework whose goal is to give the user a fulfilling social interaction experience, driven by the perception of the robot internal state and involving intuitive and computational creativity capabilities.
Chloroplast genomes of Rubiaceae: Comparative genomics and molecular phylogeny in subfamily Ixoroideae.
2020
In Rubiaceae phylogenetics, the number of markers often proved a limitation with authors failing to provide well-supported trees at tribal and generic levels. A robust phylogeny is a prerequisite to study the evolutionary patterns of traits at different taxonomic levels. Advances in next-generation sequencing technologies have revolutionized biology by providing, at reduced cost, huge amounts of data for an increased number of species. Due to their highly conserved structure, generally recombination-free, and mostly uniparental inheritance, chloroplast DNA sequences have long been used as choice markers for plant phylogeny reconstruction. The main objectives of this study are: 1) to gain in…