1,873 research outputs found
SAT based Enforcement of Domotic Effects in Smart Environments
The emergence of economically viable and efficient sensor technology provided impetus to the development of smart devices (or appliances). Modern smart environments are equipped with a multitude of smart devices and sensors, aimed at delivering intelligent services to the users of smart environments. The presence of these diverse smart devices has raised a major problem of managing environments. A rising solution to the problem is the modeling of user goals and intentions, and then interacting with the environments using user defined goals. `Domotic Effects' is a user goal modeling framework, which provides Ambient Intelligence (AmI) designers and integrators with an abstract layer that enables the definition of generic goals in a smart environment, in a declarative way, which can be used to design and develop intelligent applications. The high-level nature of domotic effects also allows the residents to program their personal space as they see fit: they can define different achievement criteria for a particular generic goal, e.g., by defining a combination of devices having some particular states, by using domain-specific custom operators. This paper describes an approach for the automatic enforcement of domotic effects in case of the Boolean application domain, suitable for intelligent monitoring and control in domotic environments. Effect enforcement is the ability to determine device configurations that can achieve a set of generic goals (domotic effects). The paper also presents an architecture to implement the enforcement of Boolean domotic effects, and results obtained from carried out experiments prove the feasibility of the proposed approach and highlight the responsiveness of the implemented effect enforcement architectur
Graded contractions of bilinear invariant forms of Lie algebras
We introduce a new construction of bilinear invariant forms on Lie algebras,
based on the method of graded contractions. The general method is described and
the -, -, and -contractions are
found. The results can be applied to all Lie algebras and superalgebras (finite
or infinite dimensional) which admit the chosen gradings. We consider some
examples: contractions of the Killing form, toroidal contractions of ,
and we briefly discuss the limit to new WZW actions.Comment: 15 page
Casimir invariants for the complete family of quasi-simple orthogonal algebras
A complete choice of generators of the center of the enveloping algebras of
real quasi-simple Lie algebras of orthogonal type, for arbitrary dimension, is
obtained in a unified setting. The results simultaneously include the well
known polynomial invariants of the pseudo-orthogonal algebras , as
well as the Casimirs for many non-simple algebras such as the inhomogeneous
, the Newton-Hooke and Galilei type, etc., which are obtained by
contraction(s) starting from the simple algebras . The dimension of
the center of the enveloping algebra of a quasi-simple orthogonal algebra turns
out to be the same as for the simple algebras from which they come by
contraction. The structure of the higher order invariants is given in a
convenient "pyramidal" manner, in terms of certain sets of "Pauli-Lubanski"
elements in the enveloping algebras. As an example showing this approach at
work, the scheme is applied to recovering the Casimirs for the (3+1)
kinematical algebras. Some prospects on the relevance of these results for the
study of expansions are also given.Comment: 19 pages, LaTe
Controlling shot noise in double-barrier magnetic tunnel junctions
We demonstrate that shot noise in Fe/MgO/Fe/MgO/Fe double-barrier magnetic
tunnel junctions is determined by the relative magnetic configuration of the
junction and also by the asymmetry of the barriers. The proposed theoretical
model, based on sequential tunneling through the system and including spin
relaxation, successfully accounts for the experimental observations for bias
voltages below 0.5V, where the influence of quantum well states is negligible.
A weak enhancement of conductance and shot noise, observed at some voltages
(especially above 0.5V), indicates the formation of quantum well states in the
middle magnetic layer. The observed results open up new perspectives for a
reliable magnetic control of the most fundamental noise in spintronic
structures.Comment: 8 pages, 4 figure
An optimal filter for the detection of galaxy clusters through weak lensing
We construct a linear filter optimised for detecting dark-matter halos in
weak-lensing data. The filter assumes a mean radial profile of the halo shear
pattern and modifies that shape by the noise power spectrum. Aiming at
separating dark-matter halos from spurious peaks caused by large-scale
structure lensing, we model the noise as being composed of weak lensing by
large-scale structures and Poisson noise from random galaxy positions and
intrinsic ellipticities. Optimal filtering against the noise requires the
optimal filter scale to be smaller than typical halo sizes. Although a perfect
separation of halos from spurious large-scale structure peaks is strictly
impossible, we use numerical simulations to demonstrate that our filter
produces substantially more sensitive, reliable and stable results than the
conventionally used aperture-mass statistic.Comment: 9 pages, 6 figures, A&A submitte
Non-standard quantum so(3,2) and its contractions
A full (triangular) quantum deformation of so(3,2) is presented by
considering this algebra as the conformal algebra of the 2+1 dimensional
Minkowskian spacetime. Non-relativistic contractions are analysed and used to
obtain quantum Hopf structures for the conformal algebras of the 2+1 Galilean
and Carroll spacetimes. Relations between the latter and the null-plane quantum
Poincar\'e algebra are studied.Comment: 9 pages, LaTe
Dynamical response and confinement of the electrons at the LaAlO3/SrTiO3 interface
With infrared ellipsometry and transport measurements we investigated the
electrons at the interface between LaAlO3 and SrTiO3. We obtained a sheet
carrier density of Ns~5-9x 10E13 cm^-2, an effective mass of m*~3m_e, and a
strongly frequency dependent mobility. The latter are similar as in bulk
SrTi1-xNbxO3 and therefore suggestive of polaronic correlations of the confined
carriers. We also determined the vertical density profile which has a strongly
asymmetric shape with a rapid initial decay over the first 2 nm and a
pronounced tail that extends to about 11 nm.Comment: 4 pages, 3 figures, 1 EPAPS file (3 figures
Quantum two-photon algebra from non-standard U_z(sl(2,R)) and a discrete time Schr\"odinger equation
The non-standard quantum deformation of the (trivially) extended sl(2,R)
algebra is used to construct a new quantum deformation of the two-photon
algebra h_6 and its associated quantum universal R-matrix. A deformed one-boson
representation for this algebra is deduced and applied to construct a first
order deformation of the differential equation that generates the two-photon
algebra eigenstates in Quantum Optics. On the other hand, the isomorphism
between h_6 and the (1+1) Schr\"odinger algebra leads to a new quantum
deformation for the latter for which a differential-difference realization is
presented. From it, a time discretization of the heat-Schr\"odinger equation is
obtained and the quantum Schr\"odinger generators are shown to be symmetry
operators.Comment: 12 pages, LaTe
Towards two-dimensional metallic behavior at LaAlO3/SrTiO3 interfaces
Using a low-temperature conductive-tip atomic force microscope in
cross-section geometry we have characterized the local transport properties of
the metallic electron gas that forms at the interface between LaAlO3 and
SrTiO3. At low temperature, we find that the carriers do not spread away from
the interface but are confined within ~10 nm, just like at room temperature.
Simulations taking into account both the large temperature and electric-field
dependence of the permittivity of SrTiO3 predict a confinement over a few nm
for sheet carrier densities larger than ~6 10^13 cm-2. We discuss the
experimental and simulations results in terms of a multi-band carrier system.
Remarkably, the Fermi wavelength estimated from Hall measurements is ~16 nm,
indicating that the electron gas in on the verge of two-dimensionality.Comment: Accepted for publication in Physical Review Letter
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