968 research outputs found
Hacia la obtención de un modelo de base de datos relacional desde sistemas heredados: un caso de estudio
Hoy en día muchas organizaciones tienen Sistemas de Información Heredados que soportan una buena parte de la operación cotidiana de las mismas. En estos sistemas es posible encontrar uso de tecnología no relacional para administrar los datos, como por ejemplo archivos planos, bases de datos jerárquicas y de redes. Cuando se necesita evolucionar el software, esto puede significar grandes desventajas. Una manera de enfrentar esta situación es generar un nuevo esquema para los datos del sistema heredado que corresponda a un modelo relacional. En este artículo se presenta un caso de estudio en el cual se aplicó un método que permite crear esquemas de bases de datos relacionales a partir de diversas fuentes de información de un sistema de información heredado.VI Workshop Bases de Datos y Minería de Datos (WBD)Red de Universidades con Carreras en Informática (RedUNCI
Hacia la obtención de un modelo de base de datos relacional desde sistemas heredados: un caso de estudio
Hoy en día muchas organizaciones tienen Sistemas de Información Heredados que soportan una buena parte de la operación cotidiana de las mismas. En estos sistemas es posible encontrar uso de tecnología no relacional para administrar los datos, como por ejemplo archivos planos, bases de datos jerárquicas y de redes. Cuando se necesita evolucionar el software, esto puede significar grandes desventajas. Una manera de enfrentar esta situación es generar un nuevo esquema para los datos del sistema heredado que corresponda a un modelo relacional. En este artículo se presenta un caso de estudio en el cual se aplicó un método que permite crear esquemas de bases de datos relacionales a partir de diversas fuentes de información de un sistema de información heredado.VI Workshop Bases de Datos y Minería de Datos (WBD)Red de Universidades con Carreras en Informática (RedUNCI
Single-phase five-level multilevel inverter based on a transistors six-pack module
This article introduces a single-phase five-level multilevel inverter based on six switches and two transformers. The proposed converter requires a single dc input source with low voltage. The disposition of switches makes it possible to build the converter with a transistors six-pack module off-the-shelves, traditionally used to build three-phase inverters, which simplifies the manufacturing process. The converter increases the voltage with two transformers; for that reason, it does not require an auxiliary step-up converter. The use of transformers (with the transformer’s turns ratio) allows for using the same topology for several input voltage levels. To verify the operation of the proposed multilevel inverter, a computer-based simulation was performed with PSIM, a software that considers parasitic components. The results show that the proposed converter can work properly
The fourth-order single-switch improved super-boost converter with reduced input current ripple
This paper introduces a new single switch DC-DC fourth-order boost converter. The proposed converter is the improved version of an existing converter known as the super-boost converter. The improved super-boost ISP converter achieves a smaller input current ripple than the super-boost converter when the same parameters in passive components are used. Conversely, smaller components can be used to achieve the same input current ripple, which leads to a compact and cheaper design. A comparative evaluation showed a reduction of 37.3% of stored energy in inductors to comply with a required input current ripple in comparison with the super-boost converter for a particular design. Experimental results are provided to corroborate this benefit of the ISB proposed topology
A step-up converter with large voltage gain and low voltage rating on capacitors
Step-up converters are widely used in many applications, such as renewable energy generation with photovoltaic panels and fuel cell stacks. In many cases, the required voltage gain is larger for those applications than a traditional boost converter can achieve. Several large-voltage gain converters have been recently studied. This paper introduces a converter topology in which the voltage gain is larger than a traditional boost converter. The main advantages of the proposed topology are: (i) it provides a large voltage gain without the use of an extreme duty cycle; (ii) its capacitors require a smaller voltage to be sustained compared with other, similar state-of-the-art converters; (iii) the voltage among the ground input and output is not pulsating; and (iv) it can be synthesized with commercial, off-the-shelf half-bridge packed transistors. The proposed converter can be employed in different applications, such as distributed generation and microgrids. This paper presents the steady-state analysis of the proposed converter in the continuous conduction mode, a short comparison with similar topologies, and their voltage on capacitors. Computer-based simulation results are provided to verify the principle of the proposed converter in different operating conditions
A role for caspase-8 and TRAIL-R2/DR5 in ER-stress induced apoptosis
Glab and colleagues examine in a recent paper apoptosis induced by some driverss of
endoplasmic reticulum (ER) stress. They conclude that in contrast to a previously published
report2
, DR5/TRAIL-R2 and caspase-8 are universally dispensable in ER stress-induced
apoptosis. We argue here that their own data and other published reports indicate that in
many models, DR5 and/or caspase-8 are essential players in apoptosis mediated by the
unfolded protein response (UPR), upon chronic ER stress
Charge separation relative to the reaction plane in Pb-Pb collisions at TeV
Measurements of charge dependent azimuthal correlations with the ALICE
detector at the LHC are reported for Pb-Pb collisions at TeV. Two- and three-particle charge-dependent azimuthal correlations in
the pseudo-rapidity range are presented as a function of the
collision centrality, particle separation in pseudo-rapidity, and transverse
momentum. A clear signal compatible with a charge-dependent separation relative
to the reaction plane is observed, which shows little or no collision energy
dependence when compared to measurements at RHIC energies. This provides a new
insight for understanding the nature of the charge dependent azimuthal
correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286
Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at = 5.02 TeV
Two-particle angular correlations between unidentified charged trigger and
associated particles are measured by the ALICE detector in p-Pb collisions at a
nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum
range 0.7 5.0 GeV/ is examined,
to include correlations induced by jets originating from low
momen\-tum-transfer scatterings (minijets). The correlations expressed as
associated yield per trigger particle are obtained in the pseudorapidity range
. The near-side long-range pseudorapidity correlations observed in
high-multiplicity p-Pb collisions are subtracted from both near-side
short-range and away-side correlations in order to remove the non-jet-like
components. The yields in the jet-like peaks are found to be invariant with
event multiplicity with the exception of events with low multiplicity. This
invariance is consistent with the particles being produced via the incoherent
fragmentation of multiple parton--parton scatterings, while the yield related
to the previously observed ridge structures is not jet-related. The number of
uncorrelated sources of particle production is found to increase linearly with
multiplicity, suggesting no saturation of the number of multi-parton
interactions even in the highest multiplicity p-Pb collisions. Further, the
number scales in the intermediate multiplicity region with the number of binary
nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/161
A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE
In this small note we are concerned with the solution of Forward-Backward
Stochastic Differential Equations (FBSDE) with drivers that grow quadratically
in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem
is a comparison result that allows comparing componentwise the signs of the
control processes of two different qgFBSDE. As a byproduct one obtains
conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio
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