Learning an Orchestra Conductor's Technique Using a Wearable Sensor Platform

Our study focuses on finding new input devices for a system allowing users with any skill to configure and conduct a virtual orchestra in real-time. As a first step, we conducted a user study to learn more about the interaction between a conductor's gestures and the orchestra 's reaction. During an orchestra rehearsal session, we observed a conductor's timing and gestures using the eWatch, a wrist-worn wearable computer and sensor platform. The gestures are analyzed and compared to the music of the orchestra

The on-orbit performance of the Orbiting Carbon Observatory-2 (OCO-2) instrument and its radiometrically calibrated products

The Orbiting Carbon Observatory-2 (OCO-2) carries and points a three-channel imaging grating spectrometer designed to collect high-resolution, co-boresighted spectra of reflected sunlight within the molecular oxygen (O_2) A-band at 0.765 microns and the carbon dioxide (CO_2) bands at 1.61 and 2.06 microns. These measurements are calibrated and then combined into soundings that are analyzed to retrieve spatially resolved estimates of the column-averaged CO_2 dry-air mole fraction, XCO_2. Variations of XCO_2 in space and time are then analyzed in the context of the atmospheric transport to quantify surface sources and sinks of CO_2. This is a particularly challenging remote-sensing observation because all but the largest emission sources and natural absorbers produce only small (< 0.25 %) changes in the background XCO_2 field. High measurement precision is therefore essential to resolve these small variations, and high accuracy is needed because small biases in the retrieved XCO_2 distribution could be misinterpreted as evidence for CO_2 fluxes. To meet its demanding measurement requirements, each OCO-2 spectrometer channel collects 24 spectra s^(−1) across a narrow ( 17 000), dynamic range (∼ 10^4), and sensitivity (continuum signal-to-noise ratio > 400). The OCO-2 instrument performance was extensively characterized and calibrated prior to launch. In general, the instrument has performed as expected during its first 18 months in orbit. However, ongoing calibration and science analysis activities have revealed a number of subtle radiometric and spectroscopic challenges that affect the yield and quality of the OCO-2 data products. These issues include increased numbers of bad pixels, transient artifacts introduced by cosmic rays, radiance discontinuities for spatially non-uniform scenes, a misunderstanding of the instrument polarization orientation, and time-dependent changes in the throughput of the oxygen A-band channel. Here, we describe the OCO-2 instrument, its data products, and its on-orbit performance. We then summarize calibration challenges encountered during its first 18 months in orbit and the methods used to mitigate their impact on the calibrated radiance spectra distributed to the science community

The extreme HBL behaviour of Markarian 501 during 2012

A multiwavelength campaign was organized to take place between March and July of 2012. Excellent temporal coverage was obtained with more than 25 instruments, including the MAGIC, FACT and VERITAS Cherenkov telescopes, the instruments on board the Swift and Fermi spacecraft, and the telescopes operated by the GASP-WEBT collaboration. Mrk 501 showed a very high energy (VHE) gamma-ray flux above 0.2 TeV of $\sim$0.5 times the Crab Nebula flux (CU) for most of the campaign. The highest activity occurred on 2012 June 9, when the VHE flux was $\sim$3 CU, and the peak of the high-energy spectral component was found to be at $\sim$2 TeV. This study reports very hard X-ray spectra, and the hardest VHE spectra measured to date for Mrk 501. The fractional variability was found to increase with energy, with the highest variability occurring at VHE, and a significant correlation between the X-ray and VHE bands. The unprecedentedly hard X-ray and VHE spectra measured imply that their low- and high-energy components peaked above 5 keV and 0.5 TeV, respectively, during a large fraction of the observing campaign, and hence that Mrk 501 behaved like an extreme high-frequency- peaked blazar (EHBL) throughout the 2012 observing season. This suggests that being an EHBL may not be a permanent characteristic of a blazar, but rather a state which may change over time. The one-zone synchrotron self-Compton (SSC) scenario can successfully describe the segments of the SED where most energy is emitted, with a significant correlation between the electron energy density and the VHE gamma-ray activity, suggesting that most of the variability may be explained by the injection of high-energy electrons. The one-zone SSC scenario used reproduces the behaviour seen between the measured X-ray and VHE gamma-ray fluxes, and predicts that the correlation becomes stronger with increasing energy of the X-rays

An intermittent extreme BL Lac: MWL study of 1ES 2344+514 in an enhanced state

Extreme high-frequency BL Lacs (EHBL) feature their synchrotron peak of the broad-band spectral energy distribution (SED) at nu(s) >= 10(17) Hz. The BL Lac object 1ES 2344+514 was included in the EHBL family because of its impressive shift of the synchrotron peak in 1996. During the following years, the source appeared to be in a low state without showing any extreme behaviours. In 2016 August, 1ES 2344+514 was detected with the groundbased gamma-ray telescope FACT during a high gamma-ray state, triggering multiwavelength (MWL) observations. We studied the MWL light curves of 1ES 2344+514 during the 2016 flaring state, using data from radio to very-high-energy (VHE) gamma-rays taken with OVRO, KAIT, KVA, NOT, some telescopes of the GASP-WEBT collaboration at the Teide, Crimean, and St. Petersburg observatories, Swift-UVOT, Swift-XRT, Fermi-LAT, FACT, and MAGIC. With simultaneous observations of the flare, we built the broad-band SED and studied it in the framework of a leptonic and a hadronic model. The VHE gamma-ray observations show a flux level of 55 per cent of the Crab Nebula flux above 300 GeV, similar to the historical maximum of 1995. The combination of MAGIC and Fermi-LAT spectra provides an unprecedented characterization of the inverse-Compton peak for this object during a flaring episode. The Gamma index of the intrinsic spectrum in the VHE gamma-ray band is 2.04 +/- 0.12(stat) +/- 0.15(sys). We find the source in an extreme state with a shift of the position of the synchrotron peak to frequencies above or equal to 1018 Hz

Ueber die Eigenschaften der oberflaechennahen Zirkulation im zentralen Nordatlantik. Analyse eines Driftbojendatensatzes

An analysis of a drifting buoy data set is presented. The objective is to arrive at a self contained description of the properties of the near-surface circulation (drogue depth 100m) in the central North Atlantic Ocean. A necessary pre-analysis step was the removal of all data from undrogued buoys. The physical parameters are deduced by averaging the data in 2 x 3 boxes. The minimum amount of data that is necessary to get nearly statistically stable results is determined by an empirical quality criterion. All important currents in the investigation area are reproduced by the near surface mean velocity field. Using a stream function approach a separation of the mean velocity field into a divergent and a non-divergent part shows that the flow is nearly non-divergent. The distribution of eddy kinetic energy (EKE) is very inhomogeneous. EKE is isotropic and concentrated along the mean currents which therefore determine its distribution. The greatest part of the total kinetic energy consists of EKE, but there are regional variations. A comparison of the deduced mean velocity field and the EKE distribution with the results of an eddy-resolving model reveals qualitative and quantitative discrepancies. The analysis of the Reynolds stress terms shows an energy transfer from the eddy field to the mean circulation in the vicinity of North Atlantic Current. Meridional sections along 30 W reveal significant seasonal variations of EKE in many regions of the North Atlantic Ocean. Regional differences in their seasonal cycle are also noticeable. The spectral energy distribution of Lagrangian and Eulerian spectra with equal total energy level is different. Due to the shorter Lagrangian time scale the cut-off frequency is at higher frequencies as in the Eulerian case. The position of the cut-off frequency varies depending on the area under consideration and characterises a special current regime. It turns out that it is not possible to analyse tidal currents with drifting buoy data. A basinwide distribution of the energy of inertia motions is deduced by complex demodulation. (orig.)SIGLEAvailable from TIB Hannover: RN 3292(244) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman