32 research outputs found
Performance study of fixed and moving relays for vehicular users with multi-cell handover under co-channel interference
In this paper, we investigate the power outage probability (OP) of a vehicular user equipment (VUE) device served by half-duplex decode-and-forward relay nodes (RNs) under co-channel interference. Both moving RNs (MRNs) and fixed RNs (FRNs) are studied, and compared with the baseline, base station (BS) to VUE direct transmission. In order to understand the benefit for vehicular users served by an RN, we consider practical channel models for different involved links as well as the impact of handover (HO) between the BS and the RNs. For an accurate comparison, we present a comprehensive framework to optimize the HO parameters, as well as we numerically optimize the FRN position which minimizes the average power OP at the VUE. FRN shows its advantage to serve its nearby VUEs. However, when vehicular penetration loss is moderate to high, MRN assisted transmission greatly outperforms transmission assisted by an FRN as well as direct transmission. Hence, the use of MRNs is very promising for improving the quality-of-service (QoS) of VUEs in future mobile communication systems
VADER - A Satellite Mission Concept For High Precision Dark Energy Studies
We present a satellite mission concept to measure the dark energy equation of
state parameter w with percent-level precision. The Very Ambitious Dark Energy
Research satellite (VADER) is a multi-wavelength survey mission joining X-ray,
optical, and IR instruments for a simultaneous spectral coverage from 4microns
(0.3eV) to 10keV over a field of view (FoV) of 1 square degree. VADER combines
several clean methods for dark energy studies, the baryonic acoustic
oscillations in the galaxy and galaxy cluster power spectrum and weak lensing,
for a joint analysis over an unrivalled survey volume. The payload consists of
two XMM-like X-ray telescopes with an effective area of 2,800cm^2 at 1.5keV and
state-of-the-art wide field DEPFET pixel detectors (0.1-10keV) in a curved
focal plane configuration to extend the FoV. The X-ray telescopes are
complemented by a 1.5m optical/IR telescope with 8 instruments for simultaneous
coverage of the same FoV from 0.3 to 4 microns. The 8 dichroic-separated bands
(u,g,r,z,J,H,K,L) provide accurate photometric galaxy redshifts, whereas the
diffraction-limited resolution of the central z-band allows precise shape
measurements for cosmic shear analysis.
The 5 year VADER survey will cover a contiguous sky area of 3,500 square
degrees to a depth of z~2 and will yield accurate photometric redshifts and
multi-wavelength object parameters for about 175,000 galaxy clusters, one
billion galaxies, and 5 million AGN. VADER will not only provide unprecedented
constraints on the nature of dark energy, but will additionally extend and
trigger a multitude of cosmic evolution studies to very large (>10 Gyrs)
look-back times.Comment: 14 pages, 7 figures, accepted for publication in the SPIE conference
proceeding
Ja spinnen die denn, die Myonen?
Das Myon-g-2-Experiment am Fermilab hat eine Abweichung des anomalen magnetischen Moments des Myons von der theoretischen Vorhersage gemessen, die nun zusammen mit dem Resultat des Brookhaven National Laboratory auf mehr als vier Sigma gestiegen ist – ein spannender Hinweis auf Physik jenseits des Standardmodells. Und die Kollaboration ist auf sehr gutem Weg, eine noch höhere experimentelle Präzision von 0,14 ppm zu erreichen, eine etwa vierfache Verbesserung gegenüber dem Vorgängerexperiment. Wichtig zu wissen ist auch, dass japanische Kollegen am J-PARC in der Nähe von Tokio daran arbeiten, ein neues Myon-g-2-Experiment aufzubauen, das ein deutlich anderes Design verwendet und damit als unabhängig angesehen werden kann. Eine zusätzliche Bestätigung der Messungen am Fermilab durch dieses neue Experiment wäre ein weiterer wichtiger Schritt, das Vertrauen in die experimentelle Bestimmung des anomalen magnetischen Momentes des Myons weiter zu erhöhen. Auf jeden Fall bleibt es spannend zu sehen, wie sich die Abweichung zwischen Experiment und Theorie in den kommenden Jahren entwickeln wird. Bleiben Sie also am Ball, um zu sehen, wer spinnt: die Myonen oder die Theorie!
Multiple Sklerose Therapie Konsensus Gruppe (MSTKG): Positionspapier zur verlaufsmodifizierenden Therapie der Multiplen Sklerose 2021 (White Paper)
Multiple sclerosis is a complex, autoimmune-mediated disease of the central nervous system characterized by inflammatory demyelination and axonal/neuronal damage. The approval of various disease-modifying therapies and our increased understanding of disease mechanisms and evolution in recent years have significantly changed the prognosis and course of the disease. This update of the Multiple Sclerosis Therapy Consensus Group treatment recommendation focuses on the most important recommendations for disease-modifying therapies of multiple sclerosis in 2021. Our recommendations are based on current scientific evidence and apply to those medications approved in wide parts of Europe, particularly German-speaking countries (Germany, Austria, Switzerland)