637,201 research outputs found
Analysing Temporal Relations – Beyond Windows, Frames and Predicates
This article proposes an approach to rely on the standard
operators of relational algebra (including grouping and ag-
gregation) for processing complex event without requiring
window specifications. In this way the approach can pro-
cess complex event queries of the kind encountered in appli-
cations such as emergency management in metro networks.
This article presents Temporal Stream Algebra (TSA) which
combines the operators of relational algebra with an analy-
sis of temporal relations at compile time. This analysis de-
termines which relational algebra queries can be evaluated
against data streams, i. e. the analysis is able to distinguish
valid from invalid stream queries. Furthermore the analysis
derives functions similar to the pass, propagation and keep
invariants in Tucker's et al. \Exploiting Punctuation Seman-
tics in Continuous Data Streams". These functions enable
the incremental evaluation of TSA queries, the propagation
of punctuations, and garbage collection. The evaluation of
TSA queries combines bulk-wise and out-of-order processing
which makes it tolerant to workload bursts as they typically
occur in emergency management. The approach has been
conceived for efficiently processing complex event queries on
top of a relational database system. It has been deployed
and tested on MonetDB
Searches for phenomena beyond the Standard Model at the LHC with the ATLAS and CMS detectors
The LHC has delivered several fb-1 of data in spring and summer 2011, opening
new windows of opportunity for discovering phenomena beyond the Standard Model.
A summary of the searches conducted by the ATLAS and CMS experiments based on
about 1 fb-1 of data is presented.Comment: Presented at Lepton-Photon 2011, Mumbai, India; 10 pages, 11 figure
Coherent acceleration of material wavepackets in modulated optical fields
We study the quantum dynamics of a material wavepacket bouncing off a
modulated atomic mirror in the presence of a gravitational field. We find the
occurrence of coherent accelerated dynamics for atoms beyond the familiar
regime of dynamical localization. The acceleration takes place for certain
initial phase space data and within specific windows of modulation strengths.
The realization of the proposed acceleration scheme is within the range of
present day experimental possibilities
Axions - Motivation, limits and searches
The axion solution of the strong CP problem provides a number of possible
windows to physics beyond the standard model, notably in the form of searches
for solar axions and for galactic axion dark matter, but in a broader context
also inspires searches for axion-like particles in pure laboratory experiments.
We briefly review the motivation for axions, astrophysical limits, their
possible cosmological role, and current searches for axions and axion-like
particles.Comment: Contribution to IRGAC 06, Barcelona. New figure for allowed axion
parameters, including hot dark matter limit
Gauss-Bonnet Black Holes at the LHC : Beyond the Dimensionality of Space
The Gauss - Bonnet invariant is one of the most promising candidates for a
quadratic curvature correction to the Einstein action in expansions of
supersymmetric string theory. We study the evaporation of such Schwarzschild -
Gauss - Bonnet black holes which could be formed at future colliders if the
Planck scale is of order a TeV, as predicted by some modern brane world models.
We show that, beyond the dimensionality of space, the corresponding coupling
constant could be measured by the LHC. This opens new windows for physics
investigation in spite of the possible screening of microphysics due to the
event horizon.Comment: Accepted by Phys. Lett.
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