3,455 research outputs found
Feature-Aware Verification
A software product line is a set of software products that are distinguished
in terms of features (i.e., end-user--visible units of behavior). Feature
interactions ---situations in which the combination of features leads to
emergent and possibly critical behavior--- are a major source of failures in
software product lines. We explore how feature-aware verification can improve
the automatic detection of feature interactions in software product lines.
Feature-aware verification uses product-line verification techniques and
supports the specification of feature properties along with the features in
separate and composable units. It integrates the technique of variability
encoding to verify a product line without generating and checking a possibly
exponential number of feature combinations. We developed the tool suite
SPLverifier for feature-aware verification, which is based on standard
model-checking technology. We applied it to an e-mail system that incorporates
domain knowledge of AT&T. We found that feature interactions can be detected
automatically based on specifications that have only feature-local knowledge,
and that variability encoding significantly improves the verification
performance when proving the absence of interactions.Comment: 12 pages, 9 figures, 1 tabl
Incommensurate-Commensurate Magnetic Phase Transition in SmRuAl
Magnetic properties of single crystalline SmRuAl have been
investigated by electrical resistivity, magnetic susceptibility, and specific
heat. We have confirmed the successive magnetic phase transitions at
K and K. Resonant x-ray diffraction has
also been performed to study the magnetic structures. Below , the
Sm moments order in an incommensurate structure with . The magnetic moments are oriented along the orthorhombic axis, which
coincides with the magnetization easy axis in the paramagnetic phase. A very
weak third harmonic peak is also observed at . The
transition at is a lock-in transition to the commensurate
structure described by . A well developed third harmonic peak
is observed at . From the discussion of the magnetic
structure, we propose that the long-range RKKY interaction plays an important
role, in addition to the strong nearest neighbor antiferromagnetic interaction.Comment: 11 pages, 12 figures, accepted in PR
CBR and MBR techniques: review for an application in the emergencies domain
The purpose of this document is to provide an in-depth analysis of current reasoning engine practice and the integration strategies of Case Based Reasoning and Model Based Reasoning that will be used in the design and development of the RIMSAT system.
RIMSAT (Remote Intelligent Management Support and Training) is a European Commission funded project designed to:
a.. Provide an innovative, 'intelligent', knowledge based solution aimed at improving the quality of critical decisions
b.. Enhance the competencies and responsiveness of individuals and organisations involved in highly complex, safety critical incidents - irrespective of their location.
In other words, RIMSAT aims to design and implement a decision support system that using Case Base Reasoning as well as Model Base Reasoning technology is applied in the management of emergency situations.
This document is part of a deliverable for RIMSAT project, and although it has been done in close contact with the requirements of the project, it provides an overview wide enough for providing a state of the art in integration strategies between CBR and MBR technologies.Postprint (published version
Stellar intensity interferometry over kilometer baselines: Laboratory simulation of observations with the Cherenkov Telescope Array
A long-held astronomical vision is to realize diffraction-limited optical
aperture synthesis over kilometer baselines. This will enable imaging of
stellar surfaces and their environments, show their evolution over time, and
reveal interactions of stellar winds and gas flows in binary star systems. An
opportunity is now opening up with the large telescope arrays primarily erected
for measuring Cherenkov light in air induced by gamma rays. With suitable
software, such telescopes could be electronically connected and used also for
intensity interferometry. With no optical connection between the telescopes,
the error budget is set by the electronic time resolution of a few nanoseconds.
Corresponding light-travel distances are on the order of one meter, making the
method practically insensitive to atmospheric turbulence or optical
imperfections, permitting both very long baselines and observing at short
optical wavelengths. Theoretical modeling has shown how stellar surface images
can be retrieved from such observations and here we report on experimental
simulations. In an optical laboratory, artificial stars (single and double,
round and elliptic) are observed by an array of telescopes. Using high-speed
photon-counting solid-state detectors and real-time electronics, intensity
fluctuations are cross correlated between up to a hundred baselines between
pairs of telescopes, producing maps of the second-order spatial coherence
across the interferometric Fourier-transform plane. These experiments serve to
verify the concepts and to optimize the instrumentation and observing
procedures for future observations with (in particular) CTA, the Cherenkov
Telescope Array, aiming at order-of-magnitude improvements of the angular
resolution in optical astronomy.Comment: 18 pages, 11 figures; Presented at SPIE conference on Astronomical
Telescopes + Instrumentation in Montreal, Quebec, Canada, June 2014. To
appear in SPIE Proc.9146, Optical and Infrared Interferometry IV
(J.K.Rajagopal, M.J.Creech-Eakman, F.Malbet, eds.), 201
Long-baseline optical intensity interferometry: Laboratory demonstration of diffraction-limited imaging
A long-held vision has been to realize diffraction-limited optical aperture
synthesis over kilometer baselines. This will enable imaging of stellar
surfaces and their environments, and reveal interacting gas flows in binary
systems. An opportunity is now opening up with the large telescope arrays
primarily erected for measuring Cherenkov light in air induced by gamma rays.
With suitable software, such telescopes could be electronically connected and
also used for intensity interferometry. Second-order spatial coherence of light
is obtained by cross correlating intensity fluctuations measured in different
pairs of telescopes. With no optical links between them, the error budget is
set by the electronic time resolution of a few nanoseconds. Corresponding
light-travel distances are approximately one meter, making the method
practically immune to atmospheric turbulence or optical imperfections,
permitting both very long baselines and observing at short optical wavelengths.
Previous theoretical modeling has shown that full images should be possible to
retrieve from observations with such telescope arrays. This project aims at
verifying diffraction-limited imaging experimentally with groups of detached
and independent optical telescopes. In a large optics laboratory, artificial
stars were observed by an array of small telescopes. Using high-speed
photon-counting solid-state detectors, intensity fluctuations were
cross-correlated over up to 180 baselines between pairs of telescopes,
producing coherence maps across the interferometric Fourier-transform plane.
These measurements were used to extract parameters about the simulated stars,
and to reconstruct their two-dimensional images. As far as we are aware, these
are the first diffraction-limited images obtained from an optical array only
linked by electronic software, with no optical connections between the
telescopes.Comment: 13 pages, 9 figures, Astronomy & Astrophysics, in press. arXiv admin
note: substantial text overlap with arXiv:1407.599
Application of a Lamb waves based technique for structural health monitoring of GFRP undercyclic loading
A Lamb wave based ultrasonic technique as well as optical image characterization was utilized to estimate a current mechanical state of glass fiber reinforced polymers (GFRP) under cyclic tension. The ultrasonic acoustic method was applied in a 'pitch-catch' mode using piezoelectric transducers adhesively bonded onto a specimen surface. Numerical evaluation of acoustic data was performed by calculating two informative parameters: maximum of amplitude of the received signal and variance of signal envelopes. Optical images were registered and then analysed by calculating Shannon entropy that makes it possible to characterize changing of GFRP specimen translucency. The obtained results were treated in order to find out the relation between the current mechanical state of a specimen and informative parameter values being computed from the acoustic and optical signals
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