3,692 research outputs found
A Graph-Based Semantics Workbench for Concurrent Asynchronous Programs
A number of novel programming languages and libraries have been proposed that
offer simpler-to-use models of concurrency than threads. It is challenging,
however, to devise execution models that successfully realise their
abstractions without forfeiting performance or introducing unintended
behaviours. This is exemplified by SCOOP---a concurrent object-oriented
message-passing language---which has seen multiple semantics proposed and
implemented over its evolution. We propose a "semantics workbench" with fully
and semi-automatic tools for SCOOP, that can be used to analyse and compare
programs with respect to different execution models. We demonstrate its use in
checking the consistency of semantics by applying it to a set of representative
programs, and highlighting a deadlock-related discrepancy between the principal
execution models of the language. Our workbench is based on a modular and
parameterisable graph transformation semantics implemented in the GROOVE tool.
We discuss how graph transformations are leveraged to atomically model
intricate language abstractions, and how the visual yet algebraic nature of the
model can be used to ascertain soundness.Comment: Accepted for publication in the proceedings of FASE 2016 (to appear
Recomendação de variedades de milho para o Sul do Brasil: rede de ensaios preliminares-Safra 2009/10.
bitstream/item/45104/1/circular-99.pd
Hubbard band or oxygen vacancy states in the correlated electron metal SrVO?
We study the effect of oxygen vacancies on the electronic structure of the
model strongly correlated metal SrVO. By means of angle-resolved
photoemission (ARPES) synchrotron experiments, we investigate the systematic
effect of the UV dose on the measured spectra. We observe the onset of a
spurious dose-dependent prominent peak at an energy range were the lower
Hubbard band has been previously reported in this compound, raising questions
on its previous interpretation. By a careful analysis of the dose dependent
effects we succeed in disentangling the contributions coming from the oxygen
vacancy states and from the lower Hubbard band. We obtain the intrinsic ARPES
spectrum for the zero-vacancy limit, where a clear signal of a lower Hubbard
band remains. We support our study by means of state-of-the-art ab initio
calculations that include correlation effects and the presence of oxygen
vacancies. Our results underscore the relevance of potential spurious states
affecting ARPES experiments in correlated metals, which are associated to the
ubiquitous oxygen vacancies as extensively reported in the context of a
two-dimensional electron gas (2DEG) at the surface of insulating
transition metal oxides.Comment: Manuscript + Supplemental Material, 12 pages, 9 figure
Long-lived non-equilibrium superconductivity in a non-centrosymmetric Rashba semiconductor
We report non-equilibrium magnetodynamics in the Rashba-superconductor GeTe,
which lacks inversion symmetry in the bulk. We find that at low temperature the
system exhibits a non-equilibrium state, which decays on time scales that
exceed conventional electronic scattering times by many orders of magnitude.
This reveals a non-equilibrium magnetoresponse that is asymmetric under
magnetic field reversal and, strikingly, induces a non-equilibrium
superconducting state distinct from the equilibrium one. We develop a model of
a Rashba system where non-equilibrium configurations relax on a finite
timescale which captures the qualitative features of the data. We also obtain
evidence for the slow dynamics in another non-superconducting Rashba system.
Our work provides novel insights into the dynamics of non-centrosymmetric
superconductors and Rashba systems in general
Data protection risk modeling into business process analysis
We present a novel way to link business process model with data protection risk management. We use established body of knowledge regarding risk manager concepts and business process towards data protections. We try to contribute to the problems that today organizations should find a suitable data protection model that could be used in as a risk framework. The purpose of this document is to define a model to describe data protection in the context of risk. Our approach including the identification of the main concepts of data
protection according to the scope of the with EU directive data protection regulation. We outline data protection model as a continuous way of protection valued organization information regarding personal identifiable information. Data protection encompass the preservation of personal data information from unauthorized access, use, modification, recording or destruction. Since this kind of service is offered in a continuous way, it is
important to stablish a way to measure the effectiveness of awareness of data subject discloses regrading personal identifiable information.info:eu-repo/semantics/publishedVersio
Second harmonic generation in SiC polytypes
LMTO calculations are presented for the frequency dependent second harmonic
generation (SHG) in the polytypes 2H, 4H, 6H, 15R and 3C of SiC. All
independent tensor components are calculated. The spectral features and the
ratios of the 333 to 311 tensorial components are studied as a function of the
degree of hexagonality. The relationship to the linear optical response and the
underlying band structure are investigated. SHG is suggested to be a sensitive
tool for investigating the near band edge interband excitations.Comment: 12 pages, 10 figure
2,3,5-Triphenyl-2H-tetrazolium chloride as a reagent for the determination of sugar mixtures by a differential reaction-rate technique
The rates of reaction of 2,3,5-triphenyl-2H-tetrazolium chloride with the more common hexoses (glucose, fructose, mannose, sorbose and galactose) and pentoses (xylose and ribose) have been studied. Under certain conditions, over a limited range of reaction, the extent of the reaction is directly proportional to the time of reaction (a "pseudo zero-order" reaction). Also, the rates of reaction of the sugars are quite different in most cases. Thus, the behaviour of this reagent is quite satisfactory for the determination of binary mixtures of most of the sugars tested, by a simple differential rate technique developed for "zero-order" competitive reactions. The rates of reaction of 2,3,5-triphenyl-2H-tetrazolium chloride with ascorbic acid, creatinine and glutathione, often found in blood serum, which interfere with most blood serum sugar analysis methods, have also been examined to determine if they would interfere with the determination. Glutathione and creatinine do not react with the reagent and do not interfere with the analysis of sugar mixtures. Ascorbic acid, however, reacts rapidly, and as little as 1-2% leads to error in the sugar-mixture determination.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32056/1/0000100.pd
The structure of Chariklo's rings from stellar occultations
Two narrow and dense rings (called C1R and C2R) were discovered around the
Centaur object (10199) Chariklo during a stellar occultation observed on 2013
June 3. Following this discovery, we planned observations of several
occultations by Chariklo's system in order to better characterize the physical
properties of the ring and main body. Here, we use 12 successful occulations by
Chariklo observed between 2014 and 2016. They provide ring profiles (physical
width, opacity, edge structure) and constraints on the radii and pole position.
Our new observations are currently consistent with the circular ring solution
and pole position, to within the km formal uncertainty for the ring
radii derived by Braga-Ribas et al. The six resolved C1R profiles reveal
significant width variations from to 7.5 km. The width of the fainter
ring C2R is less constrained, and may vary between 0.1 and 1 km. The inner and
outer edges of C1R are consistent with infinitely sharp boundaries, with
typical upper limits of one kilometer for the transition zone between the ring
and empty space. No constraint on the sharpness of C2R's edges is available. A
1 upper limit of m is derived for the equivalent width of
narrow (physical width <4 km) rings up to distances of 12,000 km, counted in
the ring plane
FACT -- The G-APD revolution in Cherenkov astronomy
Since two years, the FACT telescope is operating on the Canary Island of La
Palma. Apart from its purpose to serve as a monitoring facility for the
brightest TeV blazars, it was built as a major step to establish solid state
photon counters as detectors in Cherenkov astronomy. The camera of the First
G-APD Cherenkov Telesope comprises 1440 Geiger-mode avalanche photo diodes
(G-APD), equipped with solid light guides to increase the effective light
collection area of each sensor. Since no sense-line is available, a special
challenge is to keep the applied voltage stable although the current drawn by
the G-APD depends on the flux of night-sky background photons significantly
varying with ambient light conditions. Methods have been developed to keep the
temperature and voltage dependent response of the G-APDs stable during
operation. As a cross-check, dark count spectra with high statistics have been
taken under different environmental conditions. In this presentation, the
project, the developed methods and the experience from two years of operation
of the first G-APD based camera in Cherenkov astronomy under changing
environmental conditions will be presented.Comment: Proceedings of the Nuclear Science Symposium and Medical Imaging
Conference (IEEE-NSS/MIC), 201
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