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Search Results: 1 - 10 of 5182 matches for " Maurice Sch?nert "
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Automatic Generation of Water Masks from RapidEye Images  [PDF]
Gideon Okpoti Tetteh, Maurice Schnert
Journal of Geoscience and Environment Protection (GEP) , 2015, DOI: 10.4236/gep.2015.310003

Water is a very important natural resource and it supports all life forms on earth. It is used by humans in various ways including drinking, agriculture and for scientific research. The aim of this research was to develop a routine to automatically extract water masks from RapidEye images, which could be used for further investigation such as water quality monitoring and change detection. A Python-based algorithm was therefore developed for this particular purpose. The developed routine combines three spectral indices namely Simple Ratios (SRs), Normalized Green Index (NGI) and Normalized Difference Water Index (NDWI). The two SRs are calculated between the NIR and green band, and between the NIR and red band. The NGI is calculated by rationing the green band to the sum of all bands in each image. The NDWI is calculated by differencing the green to the NIR and dividing by the sum of the green and NIR bands. The routine generates five intermediate water masks, which are spatially intersected to create a single intermediate water mask. In order to remove very small waterbodies and any remaining gaps in the intermediate water mask, morphological opening and closing were performed to generate the final water mask. This proposed algorithm was used to extract water masks from some RapidEye images. It yielded an Overall Accuracy of 95% and a mean Kappa Statistic of 0.889 using the confusion matrix approach.

Theorie der (literarischen) Satire. Ein funktionales Modell zur Beschreibung von Textstruktur und kommunikativer Wirkung
J?rg Schnert
Textpraxis : Digitales Journal für Philologie , 2011,
Abstract: Das entworfene Modell der literarischen Satire geht davon aus, dass satirische Kommunikation innerhalb der institutionalisierten Handlungen literarischer Kommunikation durch eine besondere Funktionalisierung von textuellem System und au ertextuellen Bezügen gekennzeichnet ist, die für die Textstruktur Relevanz hat. Der Beitrag verfolgt dabei auch ein theorie- und fachgeschichtliches Ziel und dokumentiert, wie in den sp ten 1960er und im Laufe der 1970er Jahre in der deutschsprachigen Literaturwissenschaft für den Gegenstandsbereich Theorie und Geschichte der Satire der Anschluss an die internationale Diskussion hergestellt wurde.
LArGe: Background suppression using liquid argon (LAr) scintillation for 0$νββ$ decay search with enriched germanium (Ge) detectors
M. Di Marco,P. Peiffer,S. Schnert
Physics , 2006, DOI: 10.1016/j.nuclphysbps.2007.07.019
Abstract: Measurements with a bare p-type high purity germanium diode (HPGe) submerged in a 19 kg liquid argon (LAr) scintillation detector at MPIK Heidelberg are reported. The liquid argon--germanium system (LArGe) is operated as a 4$\pi$ anti-Compton spectrometer to suppress backgrounds in the HPGe. This R&D is carried out in the framework of the GERDA experiment which searches for 0$\nu\beta\beta$ decays with HPGe detectors enriched in $^{76}$Ge. The goal of this work is to develop a novel method to discriminate backgrounds in 0$\nu\beta\beta$ search which would ultimately allow to investigate the effective neutrino mass free of background events down to the inverse mass hierarchy scale. Other applications in low-background counting are expected.
Pulse Shape Analysis with a Broad-Energy Germanium Detector for the GERDA experiment
Du?an Budjá?,Marik Barnabé Heider,Oleg Chkvorets,Stefan Schnert,Nikita Khanbekov
Physics , 2008,
Abstract: To reduce background in experiments looking for rare events, such as the GERDA double beta decay experiment, it is necessary to employ active background-suppression techniques. One of such techniques is the pulse shape analysis of signals induced by the interaction of radiation with the detector. Analysis of the time-development of the impulses can distinguish between an interaction of an electron and an interaction of a multiple-scattered photon inside the detector. This information can be used to eliminate background events from the recorded data. Results of pulse-shape analysis of signals from a commercially available broad-energy germanium detector are presented and the pulse-shape discrimination capability of such detector configuration for use in low-background experiments is discussed.
Microscopic Model for the Scintillation-Light Generation and Light-Quenching in CaWO$_4$ single crystals
S. Roth,F. v. Feilitzsch,J. -C. Lanfranchi,W. Potzel,S. Schnert,A. Ulrich
Physics , 2015,
Abstract: Scintillators are employed for particle detection and identification using light-pulse shapes and light quenching factors. We developed a comprehensive model describing the light generation and quenching in CaWO$_4$ single crystals used for direct dark matter search. All observed particle-dependent light-emission characteristics can be explained quantitatively, light-quenching factors and light-pulse shapes are calculated on a microscopic basis. This model can be extended to other scintillators such as inorganic crystal scintillators, liquid noble gases or organic liquid scintillators.
Pulse shape discrimination studies with a Broad-Energy Germanium detector for signal identification and background suppression in the GERDA double beta decay experiment
Du?an Budjá?,Marik Barnabé Heider,Oleg Chkvorets,Nikita Khanbekov,Stefan Schnert
Physics , 2009, DOI: 10.1088/1748-0221/4/10/P10007
Abstract: First studies of event discrimination with a Broad-Energy Germanium (BEGe) detector are presented. A novel pulse shape method, exploiting the characteristic electrical field distribution inside BEGe detectors, allows to identify efficiently single-site events and to reject multi-site events. The first are typical for neutrinoless double beta decays (0-nu-2-beta) and the latter for backgrounds from gamma-ray interactions. The obtained survival probabilities of backgrounds at energies close to Q(76Ge) = 2039 keV are 0.93% for events from 60Co, 21% from 226Ra and 40% from 228Th. This background suppression is achieved with 89% acceptance of 228Th double escape events, which are dominated by single site interactions. Approximately equal acceptance is expected for 0-nu-2-beta-decay events. Collimated beam and Compton coincidence measurements demonstrate that the discrimination is largely independent of the interaction location inside the crystal and validate the pulse-shape cut in the energy range of Q(76Ge). The application of BEGe detectors in the GERDA and the Majorana double beta decay experiments is under study.
PMT Test Facility at MPIK Heidelberg and Double Chooz Super Vertical Slice
J. Haser,F. Kaether,C. Langbrandtner,M. Lindner,B. Reinhold,S. Schnert
Physics , 2012, DOI: 10.1016/j.nuclphysbps.2012.09.093
Abstract: Proceedings supplement for conference poster at Neutrino 2010, Athens, Greece.
Attenuation of vacuum ultraviolet light in pure and xenon-doped liquid argon - an approach to an assignment of the near-infrared emission from the mixture
A. Neumeier,T. Dandl,A. Himpsl,L. Oberauer,W. Potzel,S. Schnert,A. Ulrich
Physics , 2015, DOI: 10.1209/0295-5075/111/12001
Abstract: Results of transmission experiments of vacuum ultraviolet light through a 11.6 cm long cell filled with pure and xenon-doped liquid argon are described. Pure liquid argon shows no attenuation down to the experimental short-wavelength cut-off at 118nm. Based on a conservative approach, a lower limit of 1.10 m for the attenuation length of its own scintillation light could be derived. Adding xenon to liquid argon at concentrations on the order of parts per million leads to strong xenon-related absorption features which are used for a tentative assignment of the recently found near-infrared emission observed in electron-beam excited liquid argon-xenon mixtures. Two of the three absorption features can be explained by perturbed xenon transitions and the third one by a trapped exciton (Wannier-Mott) impurity state. A calibration curve connecting the equivalent width of the absorption line at 140 nm with xenon concentration is provided.
Prototype scintillator cell for an In-based solar neutrino detector
Dario Motta,Christian Buck,Francis Xavier Hartmann,Thierry Lasserre,Stefan Schnert,Ute Schwan
Physics , 2005, DOI: 10.1016/j.nima.2005.03.166
Abstract: We describe the work carried out at MPIK to design, model, build and characterize a prototype cell filled with a novel indium-loaded scintillator of interest for real-time low energy solar neutrino spectroscopy. First, light propagation in optical modules was studied with experiments and Monte Carlo simulations. Subsequently a 5 cm x 5 cm x 100 cm prototype detector was set up and the optical performances of several samples were measured. We first tested a benchmark PXE-based scintillator, which performed an attenuation length of ~ 4.2 m and a photo-electron yield of ~ 730 pe/MeV. Then we measured three In-loaded samples. At an In-loading of 44 g/l, an energy resolution of ~ 11.6 % and a spatial resolution of ~ 7 cm were attained for 477 keV recoil electrons. The long-range attenuation length in the cell was ~1.3 m and the estimated photo-electron yield ~ 200 pe/MeV. Light attenuation and relative light output of all tested samples could be reproduced reasonably well by MC. All optical properties of this system have remained stable over a period of > 1 y.
Hereditarily rigid relations
Miguel Couceiro,Lucien Haddad,Maurice Pouzet,Karsten Sch?lzel
Mathematics , 2015,
Abstract: An $h$-ary relation $\r$ on a finite set $A$ is said to be \emph{hereditarily rigid} if the unary partial functions on $A$ that preserve $\r$ are the subfunctions of the identity map or of constant maps. A family of relations ${\mathcal F}$ is said to be \emph{hereditarily strongly rigid} if the partial functions on $A$ that preserve every $\r \in {\mathcal F}$ are the subfunctions of projections or constant functions. In this paper we show that hereditarily rigid relations exist and we give a lower bound on their arities. We also prove that no finite hereditarily strongly rigid families of relations exist and we also construct an infinite hereditarily strongly rigid family of relations.
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