2,453 research outputs found
Smart Signs: Showing the way in Smart Surroundings
This paper presents a context-aware guidance and messaging
system for large buildings and surrounding venues. Smart Signs are
a new type of electronic door- and way-sign based on wireless sensor networks.
Smart Signs present in-situ personalized guidance and messages,
are ubiquitous, and easy to understand. They combine the easiness of
use of traditional static signs with the flexibility and reactiveness of navigation
systems. The Smart Signs system uses context information such
as user’s mobility limitations, the weather, and possible emergency situations
to improve guidance and messaging.
Minimal infrastructure requirements and a simple deployment tool make
it feasible to easily deploy a Smart Signs system on demand.
An important design issue of the Smart Signs system is privacy: the
system secures communication links, does not track users, allow almost
complete anonymous use, and prevent the system to be used as a tool
for spying on users
Planet Population Synthesis
With the increasing number of exoplanets discovered, statistical properties
of the population as a whole become unique constraints on planet formation
models provided a link between the description of the detailed processes
playing a role in this formation and the observed population can be
established. Planet population synthesis provides such a link. The approach
allows to study how different physical models of individual processes (e.g.,
proto-planetary disc structure and evolution, planetesimal formation, gas
accretion, migration, etc.) affect the overall properties of the population of
emerging planets. By necessity, planet population synthesis relies on
simplified descriptions of complex processes. These descriptions can be
obtained from more detailed specialised simulations of these processes. The
objective of this chapter is twofold: 1) provide an overview of the physics
entering in the two main approaches to planet population synthesis and 2)
present some of the results achieved as well as illustrate how it can be used
to extract constraints on the models and to help interpret observations.Comment: 23 pages, 8 figures, accepted for publication as a chapter in
Protostars and Planets VI, University of Arizona Press (2014), eds. H.
Beuther, R. Klessen, C. Dullemond, Th. Henning. Updated references relative
to v
Trends in U.S. Public Awareness of Racial and Ethnic Health Disparities (1999-2010): 2009 General Population Toplines
Not provided
Spectral and spatial observations of microwave spikes and zebra structure in the short radio burst of May 29, 2003
The unusual radio burst of May 29, 2003 connected with the M1.5 flare in AR
10368 has been analyzed. It was observed by the Solar Broadband Radio
Spectrometer (SBRS/Huairou station, Beijing) in the 5.2-7.6 GHz range. It
proved to be only the third case of a neat zebra structure appearing among all
observations at such high frequencies. Despite the short duration of the burst
(25 s), it provided a wealth of data for studying the superfine structure with
millisecond resolution (5 ms). We localize the site of emission sources in the
flare region, estimate plasma parameters in the generation sites, and suggest
applicable mechanisms for interpretating spikes and zebra-structure generation.
Positions of radio bursts were obtained by the Siberian Solar Radio Telescope
(SSRT) (5.7 GHz) and Nobeyama radioheliograph (NoRH) (17 GHz). The sources in
intensity gravitated to tops of short loops at 17 GHz, and to long loops at 5.7
GHz. Short pulses at 17 GHz (with a temporal resolution of 100 ms) are
registered in the R-polarized source over the N-magnetic polarity
(extraordinary mode). Dynamic spectra show that all the emission comprised
millisecond pulses (spikes) of 5-10 ms duration in the instantaneous band of 70
to 100 MHz, forming the superfine structure of different bursts, essentially in
the form of fast or slow-drift fibers and various zebra-structure stripes. Five
scales of zebra structures have been singled out. As the main mechanism for
generating spikes (as the initial emission) we suggest the coalescence of
plasma waves with whistlers in the pulse regime of interaction between
whistlers and ion-sound waves. In this case one can explain the appearance of
fibers and sporadic zebra-structure stripes exhibiting the frequency splitting.Comment: 11 pages, 5 figures, in press; A&A 201
Odd Association and Range Extension of Caligus rufimaculatus Wilson, 1905; Caligidae, Siphonostomatoida, Copepoda
The Caligidae (Siphonostomatoida, Copepoda) comprises more than 465 parasitic species, over 250 of which belong to Caligus Müller, 1785 (Boxshall and Halsey 2004). Caligus spp. are primarily marine; but some representatives routinely inhabit brackish or fresh water (Margolis et al. 1975). Some Caligus spp. have been widely reported from several oceans, others have been documented from a single location, and a few have only been collected as free-swimming individuals not associated with a host (Margolis et al. 1975). Caligus spp. range from being stenoxenous to euryxenous, with most species infecting actinopterygians (Actinopterygii), a much smaller group exclusively or non-exclusively infecting chondrichthyans (primarly elasmobranchs; Elasmobranchii, Chondrichthyes) (Margolis et al. 1975, Tang and Newbound 2004), and one species non-exclusively infecting an invertebrate (Ruangpan and Kabata 1984). Herein, we report a modest range extension for Caligus rufimaculatus Wilson, 1905 based on specimens collected in an odd association with a dead dolphin in the northern Gulf of Mexico (GOM) and we contribute new details regarding the morphology of the parasite
Spatial analysis of solar type III events associated with narrow band spikes at metric wavelengths
The spatial association of narrow band metric radio spikes with type III
bursts is analyzed. The analysis addresses the question of a possible causal
relation between the spike emission and the acceleration of the energetic
electrons causing the type III burst. The spikes are identified by the
Phoenix-2 spectrometer (ETH Zurich) from survey solar observations in the
frequency range from 220 MHz to 530 MHz. Simultaneous spatial information was
provided by the Nancay Radioheliograph (NRH) at several frequencies. Five
events were selected showing spikes at one or two and type III bursts at two or
more Nancay frequencies. The 3-dimensional geometry of the single events has
been reconstructed by applying different coronal density models. As a working
hypothesis it is assumed that emission at the plasma frequency or its harmonic
is the responsible radiation process for the spikes as well as for the type III
bursts. It has been found that the spike source location is consistent with the
backward extrapolation of the trajectory of the type III bursts, tracing a
magnetic field line. In one of the analyzed events, type III bursts with two
different trajectories originating from the same spike source could be
identified. These findings support the hypothesis that narrow band metric
spikes are closely related to the acceleration region.Comment: 11 pages, 9 figure
Screening current effects in Josephson junction arrays
The purpose of this work is to compare the dynamics of arrays of Josephson
junctions in presence of magnetic field in two different frameworks: the so
called XY frustrated model with no self inductance and an approach that takes
into account the screening currents (considering self inductances only). We
show that while for a range of parameters the simpler model is sufficiently
accurate, in a region of the parameter space solutions arise that are not
contained in the XY model equations.Comment: Figures available from the author
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