1,022 research outputs found
Probabilistic computing with future deep sub-micrometer devices: a modelling approach
An approach is described that investigates the potential of probabilistic "neural" architectures for computation with deep sub-micrometer (DSM) MOSFETs. Initially, noisy MOSFET models are based upon those for a 0.35 /spl mu/m MOS technology with an exaggerated 1/f characteristic. We explore the manifestation of the 1/f characteristic at the output of a 2-quadrant multiplier when the key n-channel MOSFETs are replaced by "noisy" MOSFETs. The stochastic behavior of this noisy multiplier has been mapped on to a software (Matlab) model of a continuous restricted Boltzmann machine (CRBM) - an analogue-input stochastic computing structure. Simulation of this DSM CRBM implementation shows little degradation from that of a "perfect" CRBM. This paper thus introduces a methodology for a form of "technology-downstreaming" and highlights the potential of probabilistic architectures for DSM computation
Torque magnetometry of an amorphous-alumina/strontium-titanate interface
We report torque magnetometry measurements of an oxide heterostructure consisting of an amorphous Al2O3 thin film grown on a crystalline SrTiO3 substrate (a-AO/STO) by atomic layer deposition. We find a torque response that resembles previous studies of crystalline LaAlO3/SrTiO3 (LAO/STO) heterointerfaces, consistent with strongly anisotropic magnetic ordering in the plane of the interface. Unlike crystalline LAO, amorphous Al2O3 is nonpolar, indicating that planar magnetism at an oxide interface is possible without the strong internal electric fields generated within the polarization catastrophe model. We discuss our results in the context of current theoretical efforts to explain magnetism in crystalline LAO/STO.Chemistry and Chemical Biolog
Inactivation of dispatched 1 by the chameleon mutation disrupts Hedgehog signalling in the zebrafish embryo
AbstractSearches of zebrafish EST and whole genome shotgun sequence databases for sequences encoding the sterol-sensing domain (SSD) protein motif identified two sets of DNA sequences with significant homology to the Drosophila dispatched gene required for release of secreted Hedgehog protein. Using morpholino antisense oligonucleotides, we found that inhibition of one of these genes, designated Disp1, results in a phenotype similar to that of the “you-type” mutants, previously implicated in signalling by Hedgehog proteins in the zebrafish embryo. Injection of disp1 mRNA into embryos homozygous for one such mutation, chameleon (con) results in rescue of the mutant phenotype. Radiation hybrid mapping localised disp1 to the same region of LG20 to which the con mutation was mapped by meiotic recombination analysis. Sequence analysis of disp1 cDNA derived from homozygous con mutant embryos revealed that both mutant alleles are associated with premature termination codons in the disp1 coding sequence. By analysing the expression of markers of specific cell types in the neural tube, pancreas and myotome of con mutant and Disp1 morphant embryos, we conclude that Disp1 activity is essential for the secretion of lipid-modified Hh proteins from midline structures
The Schrodinger equation with Hulthen potential plus ring-shaped potential
We present the solutions of the Schrdinger equation with the
Hulthn potential plus ring-shape potential for states
within the framework of an exponential approximation of the centrifugal
potential.Solutions to the corresponding angular and radial equations are
obtained in terms of special functions using the conventional Nikiforov-Uvarov
method. The normalization constant for the Hulthn potential is also
computed.Comment: Typed with LateX,12 Pages, Typos correcte
Gazeau-Klauder type coherent states for hypergeometric type operators
The hypergeometric type operators are shape invariant, and a factorization
into a product of first order differential operators can be explicitly
described in the general case. Some additional shape invariant operators
depending on several parameters are defined in a natural way by starting from
this general factorization. The mathematical properties of the eigenfunctions
and eigenvalues of the operators thus obtained depend on the values of the
involved parameters. We study the parameter dependence of orthogonality, square
integrability and of the monotony of eigenvalue sequence. The obtained results
allow us to define certain systems of Gazeau-Klauder coherent states and to
describe some of their properties. Our systematic study recovers a number of
well-known results in a natural unified way and also leads to new findings.Comment: An error occurring in Theorem 12 and Theorem 13 has been correcte
Photonic realization of the relativistic Kronig-Penney model and relativistic Tamm surface states
Photonic analogues of the relativistic Kronig-Penney model and of
relativistic surface Tamm states are proposed for light propagation in fibre
Bragg gratings (FBGs) with phase defects. A periodic sequence of phase slips in
the FBG realizes the relativistic Kronig-Penney model, the band structure of
which being mapped into the spectral response of the FBG. For the semi-infinite
FBG Tamm surface states can appear and can be visualized as narrow resonance
peaks in the transmission spectrum of the grating
A new approach to the exact solutions of the effective mass Schrodinger equation
Effective mass Schrodinger equation is solved exactly for a given potential.
Nikiforov-Uvarov method is used to obtain energy eigenvalues and the
corresponding wave functions. A free parameter is used in the transformation of
the wave function. The effective mass Schrodinger equation is also solved for
the Morse potential transforming to the constant mass Schr\"{o}dinger equation
for a potential. One can also get solution of the effective mass Schrodinger
equation starting from the constant mass Schrodinger equation.Comment: 14 page
Fourier Acceleration of Langevin Molecular Dynamics
Fourier acceleration has been successfully applied to the simulation of
lattice field theories for more than a decade. In this paper, we extend the
method to the dynamics of discrete particles moving in continuum. Although our
method is based on a mapping of the particles' dynamics to a regular grid so
that discrete Fourier transforms may be taken, it should be emphasized that the
introduction of the grid is a purely algorithmic device and that no smoothing,
coarse-graining or mean-field approximations are made. The method thus can be
applied to the equations of motion of molecular dynamics (MD), or its Langevin
or Brownian variants. For example, in Langevin MD simulations our acceleration
technique permits a straightforward spectral decomposition of forces so that
the long-wavelength modes are integrated with a longer time step, thereby
reducing the time required to reach equilibrium or to decorrelate the system in
equilibrium. Speedup factors of up to 30 are observed relative to pure
(unaccelerated) Langevin MD. As with acceleration of critical lattice models,
even further gains relative to the unaccelerated method are expected for larger
systems. Preliminary results for Fourier-accelerated molecular dynamics are
presented in order to illustrate the basic concepts. Possible extensions of the
method and further lines of research are discussed.Comment: 11 pages, two illustrations included using graphic
Method Families Concept: Application to Decision-Making Methods
International audienceThe role of variability in Software engineering grows increasingly as it allows developing solutions that can be easily adapted to a specific context and reusing existing knowledge. In order to deal with variability in the method engineering (ME) domain, we suggest applying the notion of method families. Method components are organized as a method family, which is configured in the given situation into a method line. In this paper, we motivate the concept of method families by comparing the existing approaches of ME. We detail then the concept of method families and illustrate it with a family of decision-making (DM) methods that we call MADISE
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