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End date: 2015 × Start date: 2015 × DDC: 004 ×

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    Precise Navigation of Small Agricultural Robots in Sensitive Areas with a Smart Plant Camera
    (Basel : MDPI, 2015) Dworak, Volker; Huebner, Michael; Selbeck, Joern
    Most of the relevant technology related to precision agriculture is currently controlled by Global Positioning Systems (GPS) and uploaded map data; however, in sensitive areas with young or expensive plants, small robots are becoming more widely used in exclusive work. These robots must follow the plant lines with centimeter precision to protect plant growth. For cases in which GPS fails, a camera-based solution is often used for navigation because of the system cost and simplicity. The low-cost plant camera presented here generates images in which plants are contrasted against the soil, thus enabling the use of simple cross-correlation functions to establish high-resolution navigation control in the centimeter range. Based on the foresight provided by images from in front of the vehicle, robust vehicle control can be established without any dead time; as a result, off-loading the main robot control and overshooting can be avoided.
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    Simple, accurate, and efficient implementation of 1-electron atomic time-dependent Schrödinger equation in spherical coordinates
    (Amsterdam : North Holland Publ. Co., 2015) Patchkovskii, Serguei; Müller, Harm Geert
    Modelling atomic processes in intense laser fields often relies on solving the time-dependent Schrödinger equation (TDSE). For processes involving ionisation, such as above-threshold ionisation (ATI) and high-harmonic generation (HHG), this is a formidable task even if only one electron is active. Several powerful ideas for efficient implementation of atomic TDSE were introduced by H.G. Muller some time ago (Muller, 1999), including: separation of Hamiltonian terms into tri-diagonal parts; implicit representation of the spatial derivatives; and use of a rotating reference frame. Here, we extend these techniques to allow for non-uniform radial grids, arbitrary laser field polarisation, and non-Hermitian terms in the Hamiltonian due to the implicit form of the derivatives (previously neglected). We implement the resulting propagator in a parallel Fortran program, adapted for multi-core execution. Cost of TDSE propagation scales linearly with the problem size, enabling full-dimensional calculations of strong-field ATI and HHG spectra for arbitrary field polarisations on a standard desktop PC.
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    Rapid aggregation of global gridded crop model outputs to facilitate cross-disciplinary analysis of climate change impacts in agriculture
    (Amsterdam [u.a.] : Elsevier Science, 2015) Villoria, Nelson B.; Elliott, Joshua; Müller, Christoph; Shin, Jaewoo; Zhao, Lan; Song, Carol
    We discuss an on-line tool that facilitates access to the large collection of climate impacts on crop yields produced by the Agricultural Model Intercomparison and Improvement Project. This collection comprises the output of seven crop models which were run on a global grid using climate data from five different general circulation models under the current set of representative pathways. The output of this modeling endeavor consists of more than 36,000 publicly available global grids at a spatial resolution of one half degree. We offer flexible ways to aggregate these data while reducing the technical barriers implied by learning new download platforms and specialized formats. The tool is accessed trough any standard web browser without any special bandwidth requirement.
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    The Open Quantum Materials Database (OQMD): assessing the accuracy of DFT formation energies
    (London : Nature Publ. Group, 2015) Kirklin, Scott; Saal, James E.; Meredig, Bryce; Thompson, Alex; Doak, Jeff W.; Aykol, Muratahan; Rühl, Stephan; Wolverton, Chris
    The Open Quantum Materials Database (OQMD) is a high-throughput database currently consisting of nearly 300,000 density functional theory (DFT) total energy calculations of compounds from the Inorganic Crystal Structure Database (ICSD) and decorations of commonly occurring crystal structures. To maximise the impact of these data, the entire database is being made available, without restrictions, at www.oqmd.org/download. In this paper, we outline the structure and contents of the database, and then use it to evaluate the accuracy of the calculations therein by comparing DFT predictions with experimental measurements for the stability of all elemental ground-state structures and 1,670 experimental formation energies of compounds. This represents the largest comparison between DFT and experimental formation energies to date. The apparent mean absolute error between experimental measurements and our calculations is 0.096 eV/atom. In order to estimate how much error to attribute to the DFT calculations, we also examine deviation between different experimental measurements themselves where multiple sources are available, and find a surprisingly large mean absolute error of 0.082 eV/atom. Hence, we suggest that a significant fraction of the error between DFT and experimental formation energies may be attributed to experimental uncertainties. Finally, we evaluate the stability of compounds in the OQMD (including compounds obtained from the ICSD as well as hypothetical structures), which allows us to predict the existence of ~3,200 new compounds that have not been experimentally characterised and uncover trends in material discovery, based on historical data available within the ICSD.
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    Digital Humanities Handbuch
    (2015-08-12) Hahn, Helene; Kalman, Tibor; Pielström, Steffen; Puhl, Johanna; Kolbmann, Wibke; Kollatz, Thomas; Neuschäfer, Markus; Stiller, Juliane; Tonne, Danah
    Um das Handbuch möglichst praxisnah zu gestalten, haben wir uns entschieden, zuerst einzelne DH-Projekte vorzustellen, um die Möglichkeiten der DH den Lebringen und ihnen zu zeigen, was in der Praxis in dem Bereich derzeit schon umgesetzt wurde. So zeigen wir in Kapitel 2, wie mit TextGrid Texte editiert und meCodicology Handschriften analysiert werden. Die folgenden drei Kapitel beschäftigen sich mit den drei Säulen, die jedes Projekt in den Digital Humanities trag Methoden und Werkzeuge, und Infrastruktur. Die Kapitel bieten erste Einführungen in die jeweilige Thematik und vermitteln den Lesern an die Praxis angelehntsie in eigenen DH-Projekten anwenden können. Die Kapitel Daten und Alles was Recht ist - Urheberrecht und Lizenzierung von Forschungsdaten weisen in die Grundlage wissenschaftlichen Forschens ein und bieten Hilfestellungen im Umgang mit Lizenzen und Dateiformaten. Das Kapitel Methoden und Werkzeuge ze Digital Humanities auf und verweist beispielhaft auf digitale Werkzeuge, die für die Beantwortung geisteswissenschaftlicher Forschungsfragen herangezogen weKapitel Infrastruktur werden Digitale Infrastrukturen, deren Komponenten und Zielstellungen näher beschrieben. Sie sind unerlässlich, um die digitale Forschunund nachhaltig zu gestalten.
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    RADAR-Team stellt Testsystem auf zweitem Projekt-Workshop in Frankfurt vor
    (Karlsruhe : KIT, 2015) Potthoff, Jan; Razum, Matthias; Kraft, Angelina
    Im Rahmen des Projekts "Research Data Repository" (RADAR) wurde am 23. Juni 2015 auf dem zweiten Projekt-Workshop der aktuelle Stand des Testsystems, das zur Archivierung und Publikation von Forschungsdaten genutzt werden kann, vorgestellt. Außerdem wurden weitere Anforderungen an das System und allgemeine Fragen des Forschungsdatenmanagements mit den Workshop-Teilnehmern diskutiert.