23,479 research outputs found
Models of Dynamic Data for Emergency Response: A Comparative Study
The first hours after a disaster happens are very chaotic and difficult but perhaps the most important for successfully fighting the consequences, saving human lives and reducing damages in private and public properties. Despite some advances, complete inventory of the information needed during the emergency response remains challenging. In the last years several nationally and internationally funded projects have concentrated on inventory of emergency response processes, structures for storing dynamic information and standards and services for accessing needed data sets. A good inventory would clarify many aspects of the information exchange such as data sets, models, representations; a good structuring would facilitate the fast access to a desired piece of information, as well as the automation of analysis of the information. Consequently the information can be used better in the decision-making process.\ud
This paper presents our work on models for dynamic data for different disasters and incidents in Europe. The Dutch data models are derived from a thorough study on emergency response procedure in the Netherlands. Two more models developed within the project HUMBOLDT reflect several cross border disaster management scenarios in Europe. These models are compared with the Geospatial Data Model of the Department of Homeland Security in USA. The paper draws conclusions about the type of geographical information needed to perform emergency response operations and the possibility to have a generic model to be used world-wide
Massive galaxies with very young AGN
Gigahertz Peaked Spectrum (GPS) radio galaxies are generally thought to be
the young counterparts of classical extended radio sources and live in massive
ellipticals. GPS sources are vital for studying the early evolution of
radio-loud AGN, the trigger of their nuclear activity, and the importance of
feedback in galaxy evolution. We study the Parkes half-Jansky sample of GPS
radio galaxies of which now all host galaxies have been identified and 80% has
their redshifts determined (0.122 < z < 1.539). Analysis of the absolute
magnitudes of the GPS host galaxies show that at z > 1 they are on average a
magnitude fainter than classical 3C radio galaxies. This suggests that the AGN
in young radio galaxies have not yet much influenced the overall properties of
the host galaxy. However their restframe UV luminosities indicate that there is
a low level of excess as compared to passive evolution models.Comment: To appear in the proceedings of "Formation and Evolution of Galaxy
Bulges", IAUS 245; M. Bureau, E. Athanassoula & B. Barbuy, ed
Persistence of the valence bond glass state in the double perovskites Ba2-xSrxYMoO6
Peer reviewedPublisher PD
Disordering to Order: de Vries behavior from a Landau theory for smectics
We show that Landau theory for the isotropic, nematic, smectic A, and smectic
C phases generically, but not ubiquitously, implies de Vries behavior. I.e., a
continuous AC transition can occur with little layer contraction; the
birefringence decreases as temperature T is lowered above this transition, and
increases again below the transition. This de Vries behavior occurs in models
with unusually small orientational order, and is preceded by a first order I
− A transition. A first order AC transition with elements of de Vries
behavior can also occur. These results correspond well with experimental work
to date.Comment: 4 pages, 2 page appendi
Passivity-based harmonic control through series/parallel damping of an H-bridge rectifier
Nowadays the H-bridge is one of the preferred solutions to connect DC loads or distributed sources to the single-phase grid. The control aims are: sinusoidal grid current with unity power factor and optimal DC voltage regulation capability. These objectives should be satisfied, regardless the conditions of the grid, the DC load/source and the converter nonlinearities. In this paper a passivity-based approach is thoroughly investigated proposing a damping-based solution for the error dynamics. Practical experiments with a real converter validate the analysis.
Open Transactions on Shared Memory
Transactional memory has arisen as a good way for solving many of the issues
of lock-based programming. However, most implementations admit isolated
transactions only, which are not adequate when we have to coordinate
communicating processes. To this end, in this paper we present OCTM, an
Haskell-like language with open transactions over shared transactional memory:
processes can join transactions at runtime just by accessing to shared
variables. Thus a transaction can co-operate with the environment through
shared variables, but if it is rolled-back, also all its effects on the
environment are retracted. For proving the expressive power of TCCS we give an
implementation of TCCS, a CCS-like calculus with open transactions
Scaling of polymers in aligned rods
We study the behavior of self avoiding polymers in a background of vertically
aligned rods that are either frozen into random positions or free to move
horizontally. We find that in both cases the polymer chains are highly
elongated, with vertical and horizontal size exponents that differ by a factor
of 3. Though these results are different than previous predictions, our results
are confirmed by detailed computer simulations.Comment: 4 pages, 4 figure
Valence bond glass on an fcc lattice in the double perovskite Ba2YMoO6
Peer reviewedPublisher PD
Processing multiple non-adjacent dependencies: evidence from sequence learning
Processing non-adjacent dependencies is considered to be one of the hallmarks of human language. Assuming that sequence-learning tasks provide a useful way to tap natural-language-processing mechanisms, we cross-modally combined serial reaction time and artificial-grammar learning paradigms to investigate the processing of multiple nested (A(1)A(2)A(3)B(3)B(2)B(1)) and crossed dependencies (A(1)A(2)A(3)B(1)B(2)B(3)), containing either three or two dependencies. Both reaction times and prediction errors highlighted problems with processing the middle dependency in nested structures (A(1)A(2)A(3)B(3-)B(1)), reminiscent of the 'missing-verb effect' observed in English and French, but not with crossed structures (A(1)A(2)A(3)B(1-)B(3)). Prior linguistic experience did not play a major role: native speakers of German and Dutch-which permit nested and crossed dependencies, respectively-showed a similar pattern of results for sequences with three dependencies. As for sequences with two dependencies, reaction times and prediction errors were similar for both nested and crossed dependencies. The results suggest that constraints on the processing of multiple non-adjacent dependencies are determined by the specific ordering of the non-adjacent dependencies (i.e. nested or crossed), as well as the number of non-adjacent dependencies to be resolved (i. e. two or three). Furthermore, these constraints may not be specific to language but instead derive from limitations on structured sequence learning.Netherlands Organisation of Scientific Research (NWO) [446-08-014]; Max Planck Institute for Psycholinguistics; Donders Institute for Brain, Cognition and Behaviour; Fundacao para a Ciencia e Tecnologia (IBB/CBME, LA, FEDER/POCI) [PTDC/PSI-PCO/110734/2009]; Stockholm Brain Institute; Vetenskapsradet; Swedish Dyslexia Foundation; Hedlunds Stiftelse; Stockholm County Council (ALF, FoUU)info:eu-repo/semantics/publishedVersio
17O NMR study of the intrinsic magnetic susceptibility and spin dynamics of the quantum kagome antiferromagnet ZnCu3(OH)6Cl2
We report through 17O NMR, an unambiguous local determination of the
intrinsic kagome lattice spin susceptibility as well as that created around
non-magnetic defects issued from natural Zn/ Cu exchange in the S=1/2 (Cu2+)
herbertsmithite ZnCu3(OH)6Cl2 compound. The issue of a singlet-triplet gap is
addressed. The magnetic response around a defect is found to markedly differ
from that observed in non-frustrated antiferromagnetic materials. Finally, we
discuss our relaxation measurements in the light of Cu and Cl NMR data
[cond-mat 070314] and suggest a flat q-dependence of the excitations.Comment: Accepted for publication in Phys. Rev. Lett., 3 jan. 2008 Figure 1
has been modified to include a two-components fit of the 17O NMR spectru
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