12,385 research outputs found
Experience with the Open Source based implementation for ATLAS Conditions Data Management System
Conditions Data in high energy physics experiments is frequently seen as
every data needed for reconstruction besides the event data itself. This
includes all sorts of slowly evolving data like detector alignment, calibration
and robustness, and data from detector control system. Also, every Conditions
Data Object is associated with a time interval of validity and a version.
Besides that, quite often is useful to tag collections of Conditions Data
Objects altogether. These issues have already been investigated and a data
model has been proposed and used for different implementations based in
commercial DBMSs, both at CERN and for the BaBar experiment. The special case
of the ATLAS complex trigger that requires online access to calibration and
alignment data poses new challenges that have to be met using a flexible and
customizable solution more in the line of Open Source components. Motivated by
the ATLAS challenges we have developed an alternative implementation, based in
an Open Source RDBMS. Several issues were investigated land will be described
in this paper:
-The best way to map the conditions data model into the relational database
concept considering what are foreseen as the most frequent queries.
-The clustering model best suited to address the scalability problem.
-Extensive tests were performed and will be described.
The very promising results from these tests are attracting the attention from
the HEP community and driving further developments.Comment: 8 pages, 4 figures, 3 tables, conferenc
The two-echelon capacitated vehicle routing problem: models and math-based heuristics
Multiechelon distribution systems are quite common in supply-chain and logistics. They are used by public administrations in their transportation and traffic planning strategies, as well as by companies, to model own distribution systems. In the literature, most of the studies address issues relating to the movement of flows throughout the system from their origins to their final destinations. Another recent trend is to focus on the management of the vehicle fleets required to provide transportation among different echelons. The aim of this paper is twofold. First, it introduces the family of two-echelon vehicle routing problems (VRPs), a term that broadly covers such settings, where the delivery from one or more depots to customers is managed by routing and consolidating freight through intermediate depots. Second, it considers in detail the basic version of two-echelon VRPs, the two-echelon capacitated VRP, which is an extension of the classical VRP in which the delivery is compulsorily delivered through intermediate depots, named satellites. A mathematical model for two-echelon capacitated VRP, some valid inequalities, and two math-heuristics based on the model are presented. Computational results of up to 50 customers and four satellites show the effectiveness of the methods developed
Global aspects of gravitomagnetism
We consider global properties of gravitomagnetism by investigating the
gravitomagnetic field of a rotating cosmic string. We show that although the
gravitomagnetic field produced by such a configuration of matter vanishes
locally, it can be detected globally. In this context we discuss the
gravitational analogue of the Aharonov-Bohm effect.Comment: 10 pages - Typeset using REVTE
Recomendações técnicas para a criação de peixes no Baixo São Francisco.
Recomendações técnicas para criação de algumas espécies de valor econômico para os sistemas de produção de peixes da região do baixo São Francisco.bitstream/item/46754/1/CPATC-DOCUMENTOS-11-RECOMENDACOES-TECNICAS-PARA-A-CRIACAO-DE-PEIXES-NO-BAIXO-SAO-FRANCISCO-FL-131.pd
Time-Reversal Symmetry Breaking and Decoherence in Chaotic Dirac Billiards
In this work, we perform a statistical study on Dirac Billiards in the
extreme quantum limit (a single open channel on the leads). Our numerical
analysis uses a large ensemble of random matrices and demonstrates the
preponderant role of dephasing mechanisms in such chaotic billiards. Physical
implementations of these billiards range from quantum dots of graphene to
topological insulators structures. We show, in particular, that the role of
finite crossover fields between the universal symmetries quickly leaves the
conductance to the asymptotic limit of unitary ensembles. Furthermore, we show
that the dephasing mechanisms strikingly lead Dirac billiards from the extreme
quantum regime to the semiclassical Gaussian regime
Uso da ressonância magnética nuclear de baixo campo na determinação rápida do teor de umidade em madeiras.
Neste trabalho é apresentada uma recomendação da utilização da técnica de ressonância magnética nuclear (RMN) de baixo campo como método alternativo na determinação rápida da umidade em madeiras. Este método utiliza o espectrômetro de RMN desenvolvido pela Embrapa Instrumentação Agropecuária e transferido para a Empresa GIL Equipamentos Especiais.bitstream/CNPDIA/9437/1/RT12_99.pd
Lagoas de estabilização natural para armazenamento de dejetos líquidos de suínos.
Desenvolvimento das lagoas de bioestabilizacao; Impermeabilizacao de lagoas com manta de plastico.bitstream/item/37501/1/doc-9.pd
Classification of areas using pixel-by-pixel and sample classifiers
There are no author-identified significant results in this report
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