6,040 research outputs found
Electron/Photon identification in ATLAS and CMS
Recent studies in ATLAS and CMS experiments for the reconstruction and
identification of electrons and photons using full Monte Carlo and testbeam
data are reportedComment: Talk given at the Hadron Collider Physic Symposium 2006 (HCP2006),
Durham, NC on behalf of ATLAS and CMS collaboration
Twelve Ways to Build CMS Crossings from ROOT Files
The simulation of CMS raw data requires the random selection of one hundred
and fifty pileup events from a very large set of files, to be superimposed in
memory to the signal event. The use of ROOT I/O for that purpose is quite
unusual: the events are not read sequentially but pseudo-randomly, they are not
processed one by one in memory but by bunches, and they do not contain orthodox
ROOT objects but many foreign objects and templates. In this context, we have
compared the performance of ROOT containers versus the STL vectors, and the use
of trees versus a direct storage of containers. The strategy with best
performances is by far the one using clones within trees, but it stays hard to
tune and very dependant on the exact use-case. The use of STL vectors could
bring more easily similar performances in a future ROOT release.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 8 pages, LaTeX, 1 eps figures. PSN
TUKT00
OVAL: the CMS Testing Robot
Oval is a testing tool which help developers to detect unexpected changes in
the behavior of their software. It is able to automatically compile some test
programs, to prepare on the fly the needed configuration files, to run the
tests within a specified Unix environment, and finally to analyze the output
and check expectations. Oval does not provide utility code to help writing the
tests, therefore it is quite independant of the programming/scripting language
of the software to be tested. It can be seen as a kind of robot which apply the
tests and warn about any unexpected change in the output. Oval was developed by
the LLR laboratory for the needs of the CMS experiment, and it is now
recommended by the CERN LCG project.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 5 pages, LaTeX, 0 eps figures. PSN
MOJT00
Abundance patterns in early-type galaxies: is there a 'knee' in the [Fe/H] vs. [alpha/Fe] relation?
Early-type galaxies (ETGs) are known to be enhanced in alpha elements, in
accordance with their old ages and short formation timescales. In this
contribution we aim to resolve the enrichment histories of ETGs. This means we
study the abundance of Fe ([Fe/H]) and the alpha-element groups ([alpha/Fe])
separately for stars older than 9.5 Gyr ([Fe/H]o, [alpha/Fe]o) and for stars
between 1.5 and 9.5 Gyr ([Fe/H]i, [alpha/Fe]i). Through extensive simulation we
show that we can indeed recover the enrichment history per galaxy. We then
analyze a spectroscopic sample of 2286 early-type galaxies from the SDSS
selected to be ETGs. We separate out those galaxies for which the abundance of
iron in stars grows throughout the lifetime of the galaxy, i.e. in which
[Fe/H]o < [Fe/H]i. We confirm earlier work where the [Fe/H] and [alpha/Fe]
parameters are correlated with the mass and velocity dispersion of ETGs. We
emphasize that the strongest relation is between [alpha/Fe] and age. This
relation falls into two regimes, one with a steep slope for old galaxies and
one with a shallow slope for younger ETGs. The vast majority of ETGs in our
sample do not show the 'knee' in the plot of [Fe/H] vs. [alpha/Fe] commonly
observed in local group galaxies. This implies that for the vast majority of
ETGs, the stars younger than 9.5 Gyrs are likely to have been accreted or
formed from accreted gas. The properties of the intermediate-age stars in
accretion-dominated ETGs indicate that mass growth through late (minor) mergers
in ETGs is dominated by galaxies with low [Fe/H] and low [alpha/Fe]. The method
of reconstructing the stellar enrichment histories of ETGs introduced in this
paper promises to constrain the star formation and mass assembly histories of
large samples of galaxies in a unique way.Comment: 22 pages, 25 figures, accepted for publication by A&
Un procedimiento y una herramienta de ayuda a la decisión para desarrollar estrategias de rehabilitación energética sostenibles para la Directiva Europea (EPBD) 2010
The 2010 EPBD asks for an economic and social analysis in order to preserve social equity and to promote innovation and building productivity. This is possible with a life cycle energy cost (LCEC) analysis, such as with the SEC (Sustainable Energy Cost) model whose bottom up approach begins with a building typology including inhabitants. Then the analysis of some representative buildings includes the identification of a technico-economical optimum and energy retrofitting scenarios for each retrofitting programme and the extrapolation for the whole building stock. An extrapolation for the whole building stock allows to set up the strategy and to identify the needed means for reaching the objectives.
SEC is a decision aid tool for optimising sustainable energy retrofitting strategies for buildings at territorial and patrimonial scales inside a sustainable development approach towards the factor 4. Various versions of the SEC model are now available for housing and for tertiary buildings.La directiva europea de 2010 sobre eficiencia energética en los edificios exige un análisis económico y social con el objetivo de preservar la equidad social, promover la innovación y reforzar la productividad en la construcción.
Esto es posible con el análisis del coste global ampliado y especialmente con el modelo SEC. El análisis “bottom up” realizado con la SEC se basa en una tipología de edificio/usuario y en el análisis de edificios representativos: la identificación del óptimo técnico-económico y elaboración de escenarios antes de hacer una extrapolación al conjunto del parque.
SEC es una herramienta de ayuda a la decisión para desarrollar estrategias territoriales o patrimoniales de rehabilitación energética. Existen diversas versiones del modelo: para edificios residenciales (unifamiliares y plurifamiliares, públicos y privados) y para edificios terciarios
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