Multi-Paradigm Reasoning for Access to Heterogeneous GIS

Accessing and querying geographical data in a uniform way has become easier in recent years. Emerging standards like WFS turn the web into a geospatial web services enabled place. Mediation architectures like VirGIS overcome syntactical and semantical heterogeneity between several distributed sources. On mobile devices, however, this kind of solution is not suitable, due to limitations, mostly regarding bandwidth, computation power, and available storage space. The aim of this paper is to present a solution for providing powerful reasoning mechanisms accessible from mobile applications and involving data from several heterogeneous sources. By adapting contents to time and location, mobile web information systems can not only increase the value and suitability of the service itself, but can substantially reduce the amount of data delivered to users. Because many problems pertain to infrastructures and transportation in general and to way finding in particular, one cornerstone of the architecture is higher level reasoning on graph networks with the Multi-Paradigm Location Language MPLL. A mediation architecture is used as a “graph provider” in order to transfer the load of computation to the best suited component – graph construction and transformation for example being heavy on resources. Reasoning in general can be conducted either near the “source” or near the end user, depending on the specific use case. The concepts underlying the proposal described in this paper are illustrated by a typical and concrete scenario for web applications

AlScN: A III-V semiconductor based ferroelectric

Ferroelectric switching is unambigiously demonstrated for the first time in a III-V semiconductor based material: AlScN -- A discovery which could help to satisfy the urgent demand for thin film ferroelectrics with high performance and good technological compatibility with generic semiconductor technology which arises from a multitude of memory, micro/nano-actuator and emerging applications based on controlling electrical polarization. The appearance of ferroelectricity in AlScN can be related to the continuous distortion of the original wurtzite-type crystal structure towards a layered-hexagonal structure with increasing Sc content and tensile strain, which is expected to be extendable to other III-nitride based solid solutions. Coercive fields which are systematically adjustable by more than 3 MV/cm, high remnant polarizations in excess of 100 \mu C/cm$^2$ which constitute the first experimental estimate of the previously inaccessible spontaneous polarization in a III-nitride based material, an almost ideally square-like hysteresis resulting in excellent piezoelectric linearity over a wide strain interval from -0.3% to +0.4% as well as a paraelectric transition temperature in excess of 600{\deg}C are confirmed. This intriguing combination of properties is to our knowledge as of now unprecedented in the field of polycrystalline ferroelectric thin films and promises to significantly advance the commencing integration of ferroelectric functionality to micro- and nanotechnology, while at the same time providing substantial insight to one of the central open questions of the III-nitride semiconductors - that of their actual spontaneous polarization

Pressure Effect on the Superconducting and Magnetic Transitions of the Superconducting Ferromagnet RuSr2GdCu2O8

The superconducting ferromagnet RuSr2GdCu2O8 was investigated at high pressure. The intra-grain superconducting transition temperature, Tc, is resolved in ac-susceptibility as well as resistivity measurements. It is shown that the pressure shift of Tc is much smaller than that of other high-Tc compounds in a similar doping state. In contrast, the ferromagnetic transition temperature, Tm, increases with pressure at a relative rate that is about twice as large as that of Tc. The high-pressure data indicate a possible competition of the ferromagnetic and superconducting states in RuSr2GdCu2O8

Focus Mediocene

This issue, following an international conference held at the IKKM in September 2017, is devoted to what may very well be the broadest media-related topic possible, even if it is accessible only through exemplary and experimental approaches: Under the title of the »Mediocene«, it presents contributions which discuss the operations and functions that intertwine media and Planet Earth. The specific relation of media and Planet Earth likely found its most striking and iconic formula in the images of the earth from outer space in 1968/69, showing the earth—according to contemporaneous descriptions—in its brilliance and splendor as the »Blue Marble«, but also in its fragility and desperate loneliness against the black backdrop of the cosmic void. Not only the creation but also the incredible distribution of this image across the globe was already at the time clearly recognized as a media eff ect. In light of space fl ight and television technology, which had expanded the reach of observation, communication, and measurement beyond both the surface of the Earth and its atmosphere, it also became clearly evident that the Planet had been a product of the early telescope by the use of which Galileo found the visual proof for the Copernican world model. Nevertheless, the »Blue Marble« image of the planet conceives of Earth not only as a celestial body, but also as a global, ecological, and economic system. Satellite and spacecraft technology and imaging continue to move beyond Earth’s orbit even as they enable precise, small-scale procedures of navigation and observation on the surface of the planet itself. These instruments of satellite navigation aff ect practices like agriculture, urban planning, and political decision-making. Most recently, three-dimensional images featuring the planet’s surface (generated from space by Synthetic Aperture Radar) or pictures from space probes have been cir-culating on the Web, altering politico-geographical practices and popular and scientifi c knowledge of the cosmos. Today, media not only participate in the shaping of the planet, but also take place on a planetary scale. Communication systems have been installed that operate all over the globe

High-resolution supernova neutrino spectra represented by a simple fit

To study the capabilities of supernova neutrino detectors, the instantaneous spectra are often represented by a quasi-thermal distribution of the form f(E) = E^alpha e^{-(alpha+1)E/E_{av}} where E_{av} is the average energy and alpha a numerical parameter. Based on a spherically symmetric supernova model with full Boltzmann neutrino transport we have, at a few representative post-bounce times, re-converged the models with vastly increased energy resolution to test the fit quality. For our examples, the spectra are well represented by such a fit in the sense that the counting rates for a broad range of target nuclei, sensitive to different parts of the spectrum, are reproduced very well. Therefore, the mean energy and root-mean-square energy of numerical spectra hold enough information to provide the correct alpha and to forecast the response of multi-channel supernova neutrino detection.Comment: 6 pages, including 4 figures and 2 tables. Clarifying paragraphs added; results unchanged. Matches published version in PR

Core-Collapse Supernovae: Reflections and Directions

Core-collapse supernovae are among the most fascinating phenomena in astrophysics and provide a formidable challenge for theoretical investigation. They mark the spectacular end of the lives of massive stars and, in an explosive eruption, release as much energy as the sun produces during its whole life. A better understanding of the astrophysical role of supernovae as birth sites of neutron stars, black holes, and heavy chemical elements, and more reliable predictions of the observable signals from stellar death events are tightly linked to the solution of the long-standing puzzle how collapsing stars achieve to explode. In this article our current knowledge of the processes that contribute to the success of the explosion mechanism are concisely reviewed. After a short overview of the sequence of stages of stellar core-collapse events, the general properties of the progenitor-dependent neutrino emission will be briefly described. Applying sophisticated neutrino transport in axisymmetric (2D) simulations with general relativity as well as in simulations with an approximate treatment of relativistic effects, we could find successful neutrino-driven explosions for a growing set of progenitor stars. First results of three-dimensional (3D) models have been obtained, and magnetohydrodynamic simulations demonstrate that strong initial magnetic fields in the pre-collapse core can foster the onset of neutrino-powered supernova explosions even in nonrotating stars. These results are discussed in the context of the present controversy about the value of 2D simulations for exploring the supernova mechanism in realistic 3D environments, and they are interpreted against the background of the current disagreement on the question whether the standing accretion shock instability (SASI) or neutrino-driven convection is the crucial agency that supports the onset of the explosion.Comment: 36 pages, 20 figures (43 eps files); submitted to Progress of Theoretical and Experimental Physics (PTEP

Une histoire de la langue de bois

La sagesse, le bon sens, l’intérêt du gouvernement, c’est d’être constamment tonifié par une opposition sérieuse, solide, constructive (J. Lang). Théâtre et politique – même combat. La scène politique peut être vue comme l’arène du monde politique en action, et les acteurs politiques sont les acteurs de ce théâtre et jouent les têtes d’affiche, ou plutôt, les têtes de liste. Ces acteurs ne sont pourtant rien sans les mots, sans un discours dont les paroles enjolivent, cachent la réalité, la m..

« La vie est brève, le désir sans fin »

Le titre du livre de Patrick Lapeyre a récemment capté mon attention dans une librairie, le bandeau « Prix Fémina 2010 » me faisant signe et je ne me suis pas fait prier pour soutenir l’économie éditoriale française. Je vous le dis d’entrée de jeu, à mon goût, le roman n’a pas été à la hauteur de mes espérances, mais je ne l’ai pas lâché en cours de route, attaché que j’étais, mine de rien, à un des personnages centraux du livre : Louis Blériot-Ringuet, 41 ans et traducteur fauché. « Il s’est..

Une histoire de la langue de bois

La sagesse, le bon sens, l’intérêt du gouvernement, c’est d’être constamment tonifié par une opposition sérieuse, solide, constructive (J. Lang). Théâtre et politique – même combat. La scène politique peut être vue comme l’arène du monde politique en action, et les acteurs politiques sont les acteurs de ce théâtre et jouent les têtes d’affiche, ou plutôt, les têtes de liste. Ces acteurs ne sont pourtant rien sans les mots, sans un discours dont les paroles enjolivent, cachent la réalité, la m..