24,766 research outputs found
RAPID WEBGIS DEVELOPMENT FOR EMERGENCY MANAGEMENT
The use of spatial data during emergency response and management helps to make faster and better decisions. Moreover spatial data should be as much updated as possible and easy to access. To face the challenge of rapid and updated data sharing the most efficient solution is largely considered the use of internet where the field of web mapping is constantly evolving. ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action) is a non profit association founded by Politecnico di Torino and SITI (Higher Institute for the Environmental Systems) as a joint project with the WFP (World Food Programme). The collaboration with the WFP drives some projects related to Early Warning Systems (i.e. flood and drought monitoring) and Early Impact Systems (e.g. rapid mapping and assessment through remote sensing systems). The Web GIS team has built and is continuously improving a complex architecture based entirely on Open Source tools. This architecture is composed by three main areas: the database environment, the server side logic and the client side logic. Each of them is implemented respecting the MCV (Model Controller View) pattern which means the separation of the different logic layers (database interaction, business logic and presentation). The MCV architecture allows to easily and fast build a Web GIS application for data viewing and exploration. In case of emergency data publication can be performed almost immediately as soon as data production is completed. The server side system is based on Python language and Django web development framework, while the client side on OpenLayers, GeoExt and Ext.js that manage data retrieval and user interface. The MCV pattern applied to javascript allows to keep the interface generation and data retrieval logic separated from the general application configuration, thus the server side environment can take care of the generation of the configuration file. The web application building process is data driven and can be considered as a view of the current architecture composed by data and data interaction tools. Once completely automated, the Web GIS application building process can be performed directly by the final user, that can customize data layers and controls to interact with the
QCD calculations for jet substructure
We present results on novel analytic calculations to describe invariant mass
distributions of QCD jets with three substructure algorithms: trimming, pruning
and the mass-drop taggers. These results not only lead to considerable insight
into the behaviour of these tools, but also show how they can be improved. As
an example, we discuss the remarkable properties of the modified mass-drop
tagger.Comment: Talk presented at various conferences including: ESI Program on Jets
and QFT, Beyond the LHC Nordita Workshop, Boost 2013, QCD@LHC 2013, LC 2013
and Radcor 201
Observation of Solitonic Vortices in Bose-Einstein Condensates
We observe solitonic vortices in an atomic Bose-Einstein condensate after
free expansion. Clear signatures of the nature of such defects are the twisted
planar density depletion around the vortex line, observed in absorption images,
and the double dislocation in the interference pattern obtained through
homodyne techniques. Both methods allow us to determine the sign of the
quantized circulation. Experimental observations agree with numerical
simulations. These solitonic vortices are the decay product of phase defects of
the BEC order parameter spontaneously created after a rapid quench across the
BEC transition in a cigar-shaped harmonic trap and are shown to have a very
long lifetime.Comment: 7 pages, 7 figure
Solitonic Vortices in Bose-Einstein Condensates
We analyse, theoretically and experimentally, the nature of solitonic
vortices (SV) in an elongated Bose-Einstein condensate. In the experiment, such
defects are created via the Kibble-Zurek mechanism, when the temperature of a
gas of sodium atoms is quenched across the BEC transition, and are imaged after
a free expansion of the condensate. By using the Gross-Pitaevskii equation, we
calculate the in-trap density and phase distributions characterizing a SV in
the crossover from an elongate quasi-1D to a bulk 3D regime. The simulations
show that the free expansion strongly amplifies the key features of a SV and
produces a remarkable twist of the solitonic plane due to the quantized
vorticity associated with the defect. Good agreement is found between
simulations and experiments.Comment: 6 pages, 4 figure
Electroweak lights from Dark Matter annihilations
The energy spectra of Standard Model particles originated from Dark Matter
annihilations can be significantly altered by the inclusion of electroweak
gauge boson radiation from the final state. A situation where this effect is
particularly important is when a Majorana Dark Matter particle annihilates into
two light fermions. This process is in p-wave and hence suppressed by the small
value of the relative velocity of the annihilating particles. The inclusion of
electroweak radiation eludes this suppression and opens up a potentially
sizeable s-wave contribution to the annihilation cross section. I will discuss
the impact of this effect on the fluxes of stable particles resulting from the
Dark Matter annihilations, which are relevant for Dark Matter indirect
searches.Comment: 4 pages, 2 figures. Contribution to the conference proceedings of
TAUP 2011, Munich - Germany (5-9 September 2011
How to Suppress Dark States in Quantum Networks and Bio-Engineered Structures
Transport across quantum networks underlies many problems, from state
transfer on a spin network to energy transport in photosynthetic complexes.
However, networks can contain dark subspaces that block the transportation, and
various methods used to enhance transfer on quantum networks can be viewed as
equivalently avoiding, modifying, or destroying the dark subspace. Here, we
exploit graph theoretical tools to identify the dark subspaces and show that
asymptotically almost surely they do not exist for large networks, while for
small ones they can be suppressed by properly perturbing the coupling rates
between the network nodes. More specifically, we apply these results to
describe the recently experimentally observed and robust transport behaviour of
the electronic excitation travelling on a genetically-engineered
light-harvesting cylinder (M13 virus) structure. We believe that these mainly
topological tools may allow us to better infer which network structures and
dynamics are more favourable to enhance transfer of energy and information
towards novel quantum technologies.Comment: 9 pages, 6 figure
Towards an understanding of jet substructure
We present first analytic, resummed calculations of the rates at which
widespread jet substructure tools tag QCD jets. As well as considering
trimming, pruning and the mass-drop tagger, we introduce modified tools with
improved analytical and phenomenological behaviours. Most taggers have double
logarithmic resummed structures. The modified mass-drop tagger is special in
that it involves only single logarithms, and is free from a complex class of
terms known as non-global logarithms. The modification of pruning brings an
improved ability to discriminate between the different colour structures that
characterise signal and background. As we outline in an extensive
phenomenological discussion, these results provide valuable insight into the
performance of existing tools and help lay robust foundations for future
substructure studies.Comment: 52 pages, 18 figures. Version to be published in JHEP: added an
Appendix about Y-trimming and addressed several points raised by the refere
Lattice QCD Production on Commodity Clusters at Fermilab
We describe the construction and results to date of Fermilab's three
Myrinet-networked lattice QCD production clusters (an 80-node dual Pentium III
cluster, a 48-node dual Xeon cluster, and a 128-node dual Xeon cluster). We
examine a number of aspects of performance of the MILC lattice QCD code running
on these clusters.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 6 pages, LaTeX, 8 eps figures. PSN
TUIT00
- …