834 research outputs found
Comparison between different electrical configurations of emergency diesel generators for redundancy and reliability improving
The failure of an emergency diesel generator could cause a blackout with economic or human losses, especially if it occurs in a hospital.
The authors performed an up to date statistic on diesel generators fails has been investigated in a hundred of hospitals. Although
standard maintenance operation has been correctly performed, it has been found a 6 % of failures for the genset per year. MTBF of
generators and main components have been investigated and updated values are reported in this paper. Components reliability is
proved to be at its maximum technological value, consequently an innovative solution is here proposed. Often neighboring buildings
or different electrical systems have separated emergency generators. Nowadays, in case of genset failure, most of the electrical
installations are not designed to be fed from other generators. Several electrical configurations for diesel generators interconnections
have been studied, in order to guarantee the mutual succor between them and therefore improving reliability. Two innovative schemes
for emergency generators connection are here proposed for a more reliable electrical design
Timed Soft Concurrent Constraint Programs: An Interleaved and a Parallel Approach
We propose a timed and soft extension of Concurrent Constraint Programming.
The time extension is based on the hypothesis of bounded asynchrony: the
computation takes a bounded period of time and is measured by a discrete global
clock. Action prefixing is then considered as the syntactic marker which
distinguishes a time instant from the next one. Supported by soft constraints
instead of crisp ones, tell and ask agents are now equipped with a preference
(or consistency) threshold which is used to determine their success or
suspension. In the paper we provide a language to describe the agents behavior,
together with its operational and denotational semantics, for which we also
prove the compositionality and correctness properties. After presenting a
semantics using maximal parallelism of actions, we also describe a version for
their interleaving on a single processor (with maximal parallelism for time
elapsing). Coordinating agents that need to take decisions both on preference
values and time events may benefit from this language. To appear in Theory and
Practice of Logic Programming (TPLP)
Superadiabatic driving of a three-level quantum system
We study superadiabatic quantum control of a three-level quantum system whose
energy spectrum exhibits multiple avoided crossings. In particular, we
investigate the possibility of treating the full control task in terms of
independent two-level Landau-Zener problems. We first show that the time
profiles of the elements of the full control Hamiltonian are characterized by
peaks centered around the crossing times. These peaks decay algebraically for
large times. In principle, such a power-law scaling invalidates the hypothesis
of perfect separability. Nonetheless, we address the problem from a pragmatic
point of view by studying the fidelity obtained through separate control as a
function of the intercrossing separation. This procedure may be a good approach
to achieve approximate adiabatic driving of a specific instantaneous eigenstate
in realistic implementations.Comment: 11 pages, 7 figure
Biometric Standards Survey
This document presents a quick survey on the most important standards regarding biometric technologies, concentrating mainly in those concerning the smartcard environment
I Documenti Elettronici nel Panorama Italiano
This document presents a short survey on the Italian electronic identity documents using biometric technology: \u27Carta d\u27Identit? Elettronica\u27 (CIE), \u27Carta Multiservizi della Difesa\u27 (CMD), \u27Permesso di Soggiorno Elettronico\u27 (PSE) and \u27Passaporto Elettronico\u27 (E-Passport)
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