290 research outputs found
Accessible user interface support for multi-device ubiquitous applications: architectural modifiability considerations
The market for personal computing devices is rapidly expanding from PC, to mobile, home entertainment systems, and even the automotive industry. When developing software targeting such ubiquitous devices, the balance between development costs and market coverage has turned out to be a challenging issue. With the rise of Web technology and the Internet of things, ubiquitous applications have become a reality. Nonetheless, the diversity of presentation and interaction modalities still drastically limit the number of targetable devices and the accessibility toward end users. This paper presents webinos, a multi-device application middleware platform founded on the Future Internet infrastructure. Hereto, the platform's architectural modifiability considerations are described and evaluated as a generic enabler for supporting applications, which are executed in ubiquitous computing environments
Multi-device application middleware: leveraging the ubiquity of the Web with webinos
The broad range of connected devices has turned the Internet into a ubiquitous concept. In addition to desktop and laptop PCs, the Internet currently connects mobile devices, home entertainment systems, and even in-car units. From this ubiquitous evolution towards sensor-rich devices, the opportunity arises for various new types of innovative software application. However, alongside rises the issue of managing the increasing diversity of device characteristics and capabilities. As device fragmentation grows, application developers are facing the need to cover a wider variety of target devices and usage scenarios. In result, maintaining a viable balance between development costs and market coverage has turned out to be an important challenge when developing applications for a ubiquitous ecosystem. In this article, we present the webinos platform, a distributed Web runtime platform that leverages the Web for supporting self-adaptive cross-device applications. In order to enable the development of such immersive ubiquitous applications, we introduce and evaluate the concept of a context-aware federated overlay architecture
Conditions for proton temperature anisotropy to drive instabilities in the solar wind
Using high-resolution data from Solar Orbiter, we investigate the plasma
conditions necessary for the proton temperature anisotropy driven mirror-mode
and oblique firehose instabilities to occur in the solar wind. We find that the
unstable plasma exhibits dependencies on the angle between the direction of the
magnetic field and the bulk solar wind velocity which cannot be explained by
the double-adiabatic expansion of the solar wind alone. The angle dependencies
suggest that perpendicular heating in Alfv\'enic wind may be responsible. We
quantify the occurrence rate of the two instabilities as a function of the
length of unstable intervals as they are convected over the spacecraft. This
analysis indicates that mirror-mode and oblique firehose instabilities require
a spatial interval of length greater than 2 to 3 unstable wavelengths in order
to relax the plasma into a marginally stable state and thus closer to
thermodynamic equilibrium in the solar wind. Our analysis suggests that the
conditions for these instabilities to act effectively vary locally on scales
much shorter than the correlation length of solar wind turbulence.Comment: 16 pages, 8 figures. Accepted for publication in Ap
Evaluation of the marginal fit of three margin designs of resin composite crowns using CAD/CAM
OBJECTIVES:
To examine the marginal fit of resin composite crowns manufactured with the CEREC 3 system employing three different margin designs; bevel, chamfer and shoulder, by means of a replica technique and a luting agent.
METHODS:
Three master casts were fabricated from an impression of a typodont molar tooth and a full-coverage crown prepared with a marginal finish of a bevel, a chamfer and a shoulder. Each cast was replicated 10 times (n = 10). Scanning of the replicas and crown designing was performed using the CEREC ScanTM system. The crowns were milled from Paradigm MZ100TM composite resin blocks. The marginal fit of the crowns was evaluated with a replica technique (AquasilTM LV, Dentsply), and with a resin composite cement (RelyXTM Unicem, AplicapTM) and measured with a travelling microscope. Statistical analysis was performed using two-way ANOVA.
RESULTS:
For the replica technique the average marginal gaps recorded were: Bevel Group 105±34 mm, Chamfer Group 94±27 mm and Shoulder Group 91±22 mm. For the resin composite cement the average marginal gaps were: Bevel Group 102±28 mm, Chamfer Group 91±11 mm and Shoulder Group 77±8 mm. Two-way ANOVA analysis showed that there was no statistically significant difference between the three groups of finishing lines regardless of the cementation technique used.
CONCLUSIONS:
The marginal gap of resin composite crowns manufactured with the CEREC 3 system is within the range of clinical acceptance, regardless of the finishing line prepared or the cementation technique used
Timeless path integral for relativistic quantum mechanics
Starting from the canonical formalism of relativistic (timeless) quantum
mechanics, the formulation of timeless path integral is rigorously derived. The
transition amplitude is reformulated as the sum, or functional integral, over
all possible paths in the constraint surface specified by the (relativistic)
Hamiltonian constraint, and each path contributes with a phase identical to the
classical action divided by . The timeless path integral manifests the
timeless feature as it is completely independent of the parametrization for
paths. For the special case that the Hamiltonian constraint is a quadratic
polynomial in momenta, the transition amplitude admits the timeless Feynman's
path integral over the (relativistic) configuration space. Meanwhile, the
difference between relativistic quantum mechanics and conventional
nonrelativistic (with time) quantum mechanics is elaborated on in light of
timeless path integral.Comment: 41 pages; more references and comments added; version to appear in
CQ
Formal matched asymptotics for degenerate Ricci flow neckpinches
Gu and Zhu have shown that Type-II Ricci flow singularities develop from
nongeneric rotationally symmetric Riemannian metrics on , for all . In this paper, we describe and provide plausibility arguments for a
detailed asymptotic profile and rate of curvature blow-up that we predict such
solutions exhibit
Acceleration of the Solar Wind as a Result of the Reconnection of Open Magnetic Flux with Coronal Loops
There are compelling observations of a clear anti‐correlation between solar wind flow speed and coronal electron temperature, as determined from solar wind ionic charge states. A simple theory is presented which can account for these observations, including the functional form of the correlation: Solar wind flow speed squared varies essentially linearly as the inverse of the coronal electron temperature. In this theory, magnetic field lines in the corona that open into the heliosphere reconnect with coronal loops near their base. This process displaces the open field line, and disturbs and imparts energy into the overlying corona, thereby determining the Poynting vector into the corona. This process releases mass from the loop into the corona, and determines the mass flux of the solar wind. The Poynting and mass flux into the corona determine the final speed of the solar wind, and yield a relationship that provides an excellent fit to observations. © 2003 American Institute of PhysicsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87652/2/287_1.pd
On "many black hole" space-times
We analyze the horizon structure of families of space times obtained by
evolving initial data sets containing apparent horizons with several connected
components. We show that under certain smallness conditions the outermost
apparent horizons will also have several connected components. We further show
that, again under a smallness condition, the maximal globally hyperbolic
development of the many black hole initial data constructed by Chrusciel and
Delay, or of hyperboloidal data of Isenberg, Mazzeo and Pollack, will have an
event horizon, the intersection of which with the initial data hypersurface is
not connected. This justifies the "many black hole" character of those
space-times.Comment: several graphic file
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