Evaluation of the Electromagnetic Environment Around Underground HVDC Lines

This paper analyses the magnetic-field emissions of a high-voltage dc transmission line constituted by two couples of underground cables laid along a highway. The transmission system, including all its components (transformers, converters filters, and line), is modeled through a circuital approach, which provides the distribution of the current harmonics along the line length. The magnetic field produced in the environment is then estimated by a hybrid finite element/boundary element method. The electromagnetic interferences with existing appliances and the human exposure to magnetic fields are investigated considering different laying configurations, conductor dispositions, and supply conditions. Compliance with regulations limiting human exposure and technical standards ensuring electromagnetic compatibility of appliances and devices are assessed

Quantum Interference and Decoherence in Single-Molecule Junctions: How Vibrations Induce Electrical Current

Quantum interference effects and decoherence mechanisms in single-molecule junctions are analyzed employing a nonequilibrium Green's function approach. Electrons tunneling through quasi-degenerate states of a nanoscale molecular junction exhibit interference effects. We show that electronic-vibrational coupling, inherent to any molecular junction, strongly quenches such interference effects. As a result, the electrical current can be significantly larger than without electronic-vibrational coupling. The analysis reveals that the quenching of quantum interference is particularly pronounced if the junction is vibrationally highly excited, e.g. due to current-induced nonequilibrium effects in the resonant transport regime.Comment: 11 pages, 4 figure

Optimization of the e-e- option for the ILC

The e-e- running mode is one of the interesting physics options at the International Linear Collider (ILC). The luminosity for e-e- collisions is reduced by the beam-beam effects. The resulting beamstrahlung energy loss and beam-beam deflection angles as function of the vertical transverse offset are different compared to the e+e- collisions. In this paper, the dependence of these observables with the offset for different beam sizes has been analyzed to optimize performances for the e-e- mode, taking into account the requirements of the beam-beam deflection based intra-train feedback system. A first study of the implications for the final focus and extraction line optics is also presented for the cases of the 20 mrad and 2 mrad ILC base line crossing angle geometries

Uso de Sentinel-2 y datos auxiliares para la generación, mediante clasificación de imágenes, del Mapa de Usos y Cubiertas del Suelo de Cataluña 2017

[EN] This paper details the process of generating the 2017 Land Use/Land Cover Map of Catalonia (MUCSC) using automatic classification of satellite imagery and auxiliary cartographic and remote sensing data. A total of 60 images (6 dates for each of the 10 tiles covering Catalonia) captured by the Sentininel-2A and Sentinel-2B satellites were used. These images as well as texture variables, terrain models derived from lidar processing, and vegetation and wetness indices were classified using the k-Nearest Neighbor algorithm (kNN) to obtain a map with 25 categories. The categories related to urbanized areas (urban areas, urbanizations and industrial zones/ commercial areas), road infrastructures and burned areas were edited using official cartographic datasets of the Catalan Government [Generalitat]. The results have an overall accuracy greater than 98 %, which was evaluated with a set of more than 8.6 million independent test pixels. This work represents an important milestone in terms of the computational effort it involves due to the territorial extension (32 000 km2), the spatial detail of between 2 and 20 m, the use of up to 58 variables, the relative completeness of the legend and the level of success achieved. The MUCSC 2017, which is part of a 30-year quinquennial series beginning in 1987, can be downloaded in different formats (also in MMZX: new ISO 19165-2) and at resolutions of 10 m and 30 m pixel side from the Ministry of Territory and Sustainability website of the Catalan Government.[ES] En este artículo se detalla el proceso de generación del Mapa de Usos y Cubiertas del Suelo de Cataluña (MUCSC) 2017 mediante clasificación automática de imágenes de satélite y datos cartográficos y de teledetección auxiliares. Con este propósito se han utilizado un total de 60 imágenes (6 fechas sobre cada una de las 10 teselas que cubren Cataluña) captadas por los satélites 2A y 2B de la constelación Sentinel-2. Estos datos, junto con variables de textura, modelos del terreno derivados del procesado lidar para todo el territorio e índices de vegetación y humedad, han sido clasificados con el algoritmo de inteligencia artificial kNN para obtener un mapa de 25 categorías, de las cuales las referentes a zonas urbanizadas (zonas urbanas, urbanizaciones y zonas industriales y comerciales), vías de comunicación y zonas quemadas han sido editadas utilizando bases cartográficas oficiales de la Generalitat [Gobierno] de Catalunya. Los resultados muestran un acierto global superior al 98 % evaluado mediante un conjunto de más de 8,6 millones de píxeles independientes de test. Este trabajo representa un hito importante tanto por el esfuerzo de cálculo que ha supuesto (extensión territorial de 32.000 km2, detalle espacial de entre 2 y 20 m y uso de hasta 58 variables), como por la relativa completitud de la leyenda y por el nivel de acierto conseguido. El MUCSC 2017, que forma parte de una serie quinquenal de 30 años desde 1987, está disponible para descarga en distintos formatos (también en MMZX: nueva ISO 19165-2) y a resoluciones de 10 m y 30 m de lado de píxel a través de la página web en el Departamento de Territorio y Sostenibilidad de la Generalitat de Catalunya.This study was funded by the Generalitat (Grumets SGR2014-1491) and by the Spanish MCIU through the NEWFORLAND project (RTI2018-099397-B-C21 MCIU/AEI/ERDF, EU). X. Pons is the recipient of an ICREA Academia 2016 -2020 Excellence in Research Grant.González-Guerrero, O.; Pons, X. (2020). The 2017 Land Use/Land Cover Map of Catalonia based on Sentinel-2 images and auxiliary data. Revista de Teledetección. 0(55):81-92. https://doi.org/10.4995/raet.2020.13112OJS8192055Cea, C., Cristóbal, J., Pons, X. 2007. An improved methodology to map snow cover by means of Landsat and MODIS imagery. En: Geoscience and Remote Sensing Symposium, 2007. IGARSS 2007. Barcelona. IEEE International, 4217-4220. DOI https://doi.org/10.1109/IGARSS.2007.4423781Elvidge, C.D., Sutton, P.C., Wagner, T.W., Ryznar, R., Goetz, S.J., Smith, A.J., Jantz, C., Seto, K., Imhoff, M.L., Vogelmann, J., wang, Y.Q., Milesi, C., Nemani, R. 2004. Urbanization. En: Gutman, G. et al. (ed.). Land change science: Observing, monitoring, and understanding trajectories of change on the earth's surface. Dordrecht, Países Bajos: Kluwer Academic Publishers, pp. 315-328. https://doi.org/10.1007/978-1-4020-2562-4_18ESA. 2015. Sentinel-2 User Handbook. Recuperado de https://sentinel.esa.int/documents/247904/685211/ Sentinel-2_User_Handbook Último acceso: 4 de febrero, 2020.González-Guerrero, O., Pons-Fernández, X., Bassols- Morey, R., Camps-Fernandez, F.J. 2019. Dinàmica de les superfícies de conreu a Catalunya mitjançant Teledetecció en el període 1987-2012. Quaderns Agraris, 46, 59-91.Hansen, M.C., Loveland, T.R. 2012. A review of large area monitoring of land cover change using Landsat data. Remote Sensing of Environment, 122, 66-74. https://doi.org/10.1016/j.rse.2011.08.024ICC. 1992. Mapa d'usos del sòl de Catalunya. Institut Cartogràfic de Catalunya. Barcelona. 118 p.ICGC (2017). Datos lidar. Institut Cartogràfic i Geològic de Catalunya. Recuperado de https://www.icgc.cat/ es/Descargas/Elevaciones/Datos-lidar Último acceso: 1 de mayo, 2020.Loveland, T.R., Dwyer, J.L. 2012. Landsat: Building a strong future. Remote Sensing of Environment, 122, 22-29. https://doi.org/10.1016/j.rse.2011.09.022Moré, G., Pons, X. 2007. Influencia del número de imágenes en la calidad de la cartografía detallada de vegetación forestal. Revista de Teledetección, 28, 61- 68. Recuperado de http://www.aet.org.es/revistas/ revista28/7-111_More_revisado.pdf Último acceso: 1 de mayo, 2020.Padial, M., Vidal-Macua, J.J., Serra, P., Ninyerola, M., Pons, X. 2019. Aplicación de filtros multicriterio basados en NDVI para la extracción de áreas de entrenamiento desde la base de datos SIOSE. Ruiz L.A., Estornell J., Calle A., Antuña-Sánchez J.C. (eds) Teledetección: hacia una visión global del cambio climático, pp. 311-314. ISBN: 978- 84-1320-038-5. Libro de actas XVIII Congreso de la Asociación Española de Teledetección, 24 - 27 Septiembre, Valladolid (Spain).Padró, J.C., Pons, X., Aragonés, D., Díaz-Delgado, R., García, D., Bustamante, J., Pesquer, L., Domingo- Marimon, C., González-Guerrero, O., Cristóbal, J., Doktor, D., Lange, M. 2017. Radiometric Correction of Simultaneously Acquired Landsat-7/Landsat-8 and Sentinel-2A Imagery Using Pseudoinvariant Areas (PIA): Contributing to the Landsat Time Series Legacy. Remote Sensing, 9(12), 1319. https://doi.org/10.3390/rs9121319Padró, J.C., Muñoz, F.J., Ávila, L.A., Pesquer, L., Pons, X. 2018. Radiometric Correction of Landsat-8 and Sentinel-2A Scenes Using Drone Imagery in Synergy with Field Spectroradiometry. Remote Sensing, 10(11), 1687. https://doi.org/10.3390/rs10111687Pons, X. 2004. MiraMon. Sistema de Información Geográfica y software de Teledetección. Centre de Recerca Ecològica i Aplicacions Forestals, CREAF. Bellaterra. ISBN: 84-931323-4-9. Recuperado de http://www.miramon.cat/Index_es.htm Último acceso: 1 de mayo, 2020.Pons, X., Ninyerola, M. 2008. Mapping a topographic global solar radiation model implemented in a GIS and refined with ground data. International Journal of Climatology, 28(13), 1821-1834. https://doi.org/10.1002/joc.1676Pons, X., Pesquer, L., Cristóbal, J., González- Guerrero, O. 2014. Automatic and improved radiometric correction of Landsat imagery using reference values from MODIS surface reflectance images. International Journal of Applied Earth Observation and Geoinformation, 33, 243-254. https://doi.org/10.1016/j.jag.2014.06.002Pons X., Masó J. 2016. A comprehensive open package format for preservation and distribution of geospatial data and metadata. Computers & Geosciences, 97, 89-97. https://doi.org/10.1016/j.cageo.2016.09.001Townshend, J.R., Masek, J.G., Huang, C., Vermote, E.F., Gao, F., Channan, S., Sexton, J.O., Feng, M., Narasimhan, R., Kim, D., Song, K., Song, D., Song, X. P., Noojipady, P., Tan, B., Hansen, M.C., Li, M., Wolfe, R.E. 2012. Global characterization and monitoring of forest cover using Landsat data: Opportunities and challenges. International Journal of Digital Earth, 5(5), 373-397. https://doi.org/10.1080/17538947.2012.713190Woodcock, C.E., Allen, R., Anderson, M., Belward, A., Bindschadler, R., Cohen, W., Gao, F., Goward, S.N., Helder, D., Helmer, E., Nemani, R., Oreopoulos, L., Schott, J., Thenkabail, P.S., Vermote, E.F., Vogelmann, J., Wulder, M.A., Wynne, R. 2008. Free access to Landsat imagery. Science, 320(5879), 1011. https://doi.org/10.1126/science.320.5879.1011aWulder, M.A., Masek, J.G., Cohen, W.B., Loveland, T.R., Woodcock, C.E. 2012. 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Switching the Conductance of a Molecular Junction using a Proton Transfer Reaction

A novel mechanism for switching a molecular junction based on a proton transfer reaction triggered by an external electrostatic field is proposed. As a specific example to demonstrate the feasibility of the mechanism, the tautomers [2,5-(4-hydroxypyridine)] and {2,5-[4(1H)-pyridone]} are considered. Employing a combination of first-principles electronic structure calculations and Landauer transport theory, we show that both tautomers exhibit very different conductance properties and realize the "on" and "off" states of a molecular switch. Moreover, we provide a proof of principle that both forms can be reversibly converted into each other using an external electrostatic field.Comment: 14 pages, 5 figure

Near-threshold high-order harmonic spectroscopy with aligned molecules

We study high-order harmonic generation in aligned molecules close to the ionization threshold. Two distinct contributions to the harmonic signal are observed, which show very different responses to molecular alignment and ellipticity of the driving field. We perform a classical electron trajectory analysis, taking into account the significant influence of the Coulomb potential on the strong-field-driven electron dynamics. The two contributions are related to primary ionization and excitation processes, offering a deeper understanding of the origin of high harmonics near the ionization threshold. This work shows that high harmonic spectroscopy can be extended to the near-threshold spectral range, which is in general spectroscopically rich.Comment: 4 pages, 4 figure

XNect: Real-time Multi-person 3D Human Pose Estimation with a Single RGB Camera

We present a real-time approach for multi-person 3D motion capture at over 30 fps using a single RGB camera. It operates in generic scenes and is robust to difficult occlusions both by other people and objects. Our method operates in subsequent stages. The first stage is a convolutional neural network (CNN) that estimates 2D and 3D pose features along with identity assignments for all visible joints of all individuals. We contribute a new architecture for this CNN, called SelecSLS Net, that uses novel selective long and short range skip connections to improve the information flow allowing for a drastically faster network without compromising accuracy. In the second stage, a fully-connected neural network turns the possibly partial (on account of occlusion) 2D pose and 3D pose features for each subject into a complete 3D pose estimate per individual. The third stage applies space-time skeletal model fitting to the predicted 2D and 3D pose per subject to further reconcile the 2D and 3D pose, and enforce temporal coherence. Our method returns the full skeletal pose in joint angles for each subject. This is a further key distinction from previous work that neither extracted global body positions nor joint angle results of a coherent skeleton in real time for multi-person scenes. The proposed system runs on consumer hardware at a previously unseen speed of more than 30 fps given 512x320 images as input while achieving state-of-the-art accuracy, which we will demonstrate on a range of challenging real-world scenes