10,201 research outputs found
WAVELET BASED NONLINEAR SEPARATION OF IMAGES
This work addresses a real-life problem corresponding
to the separation of the nonlinear mixture of images which
arises when we scan a paper document and the image from
the back page shows through.
The proposed solution consists of a non-iterative procedure
that is based on two simple observations: (1) the high
frequency content of images is sparse, and (2) the image
printed on each side of the paper appears more strongly in
the mixture acquired from that side than in the mixture acquired from the opposite side.
These ideas had already been used in the context of nonlinear denoising source separation (DSS). However, in that method the degree of separation achieved by applying these ideas was relatively weak, and the separation had to be improved by iterating within the DSS scheme. In this paper the application of these ideas is improved by changing the competition function and the wavelet transform that is used. These improvements allow us to achieve a good separation in one shot, without the need to integrate the process into an iterative DSS scheme. The resulting separation process is both nonlinear and non-local.
We present experimental results that show that the method
achieves a good separation quality
Spin(7)-manifolds in compactifications to four dimensions
We describe off-shell M-theory compactifications down to four
dimensions in terms of eight-dimensional manifolds equipped with a topological
-structure. Motivated by the exceptionally generalized geometry
formulation of M-theory compactifications, we consider an eight-dimensional
manifold equipped with a particular set of tensors
that allow to naturally embed in a family of
-structure seven-dimensional manifolds as the leaves of a
codimension-one foliation. Under a different set of assumptions,
allows to make into a principal bundle, which is
equipped with a topological -structure if the base is equipped with a
topological -structure. We also show that can be
naturally used to describe regular as well as a singular elliptic fibrations on
, which may be relevant for F-theory applications, and prove
several mathematical results concerning the relation between topological
-structures in seven dimensions and topological -structures in
eight dimensions.Comment: 50 pages. We have included Proposition 6.4 about elliptic fibrations
in relation to a pair of vector fields. We have also included Remark 5.13,
thanks to an internal communication by Dominic Joyce. Discussion about the
relation of singular foliations and D7-branes include
National Policies to Attract FDI in R&D: An Assessment of Brazil and Selected Countries
This paper is part of a project based on a broad data collection of policies in selected countries, with a special focus on the attraction of foreign R&D investments. The purpose of the research is to contribute to effective policy-making, capable of fostering multinational corporations? (MNCs) investments in Brazil. In this context, the paper aims at identifying and examining the main policies to attract MNC technological activities in China, India, Ireland, Israel, Singapore, and Taiwan, in order to illustrate successful experiences and, based on them, to analyse the Brazilian case. The experiences and, based on them, to analyse the Brazilian case. The international experiences are analysed bearing in mind that foreign direct investment (FDI) attraction policies are part of industrial and development policies, and should not be assessed or used in isolation. ...industrial policy, technology, foreign direct investment, MNC R&D activites
THE USE OF BUDGETS IN FORECASTING THE ACTIVITY OF THE FIRM
The firm’s activity is recommended to develop in a permanent equilibrium between incomes and expenses. In the actual stage of transition of Romanian economy, the firms can not maintain this equilibrium because the expenses determined by the achievement of production overtake the level of the incomes obtained from the selling of production even when certain branches of activity are subsidized from the public budget. In these conditions, finding the methods that allow the sizing and control of the equilibrium relation between expenses and incomes represents a problem with which the firm’s management confronts. From this point of view the budget can become an instrument of correlation and especially of turning to good account the relation between incomes and expenses. Budgeting becomes a systematic economic practice that assumes the development of a process of formal assignment of financial resources that aim at the achievement of some established objectives for the future periods.budget, budgeting, forecasting, management by using budgets, expenditure budget, budget holders, manufacturing costs.
The Unusual Super-Luminous Supernovae SN 2011kl and ASASSN-15lh
Two recently discovered very luminous supernovae (SNe) present stimulating
cases to explore the extents of the available theoretical models. SN 2011kl
represents the first detection of a supernova explosion associated with an
ultra-long duration gamma ray burst. ASASSN-15lh was even claimed as the most
luminous SN ever discovered, challenging the scenarios so far proposed for
stellar explosions. Here we use our radiation hydrodynamics code in order to
simulate magnetar powered SNe. To avoid explicitly assuming neutron star
properties we adopt the magnetar luminosity and spin-down timescale as free
parameters of the model. We find that the light curve (LC) of SN 2011kl is
consistent with a magnetar power source, as previously proposed, but we note
that some amount of 56^Ni (> 0.08 M_sun) is necessary to explain the low
contrast between the LC peak and tail. For the case of ASASSN-15lh we find
physically plausible magnetar parameters that reproduce the overall shape of
the LC provided the progenitor mass is relatively large (a mass of the ejecta
approx 6 M_sun). The ejecta hydrodynamics of this event is dominated by the
magnetar input, while the effect is more moderate for SN 2011kl. We conclude
that a magnetar model may be used for the interpretation of these events and
that the hydrodynamic modeling is necessary to derive the properties of
powerful magnetars and their progenitors.Comment: Accepted by Astrophysical Journal Letters, 5 pages, 5 figure
Multiscale Fractal Descriptors Applied to Nanoscale Images
This work proposes the application of fractal descriptors to the analysis of
nanoscale materials under different experimental conditions. We obtain
descriptors for images from the sample applying a multiscale transform to the
calculation of fractal dimension of a surface map of such image. Particularly,
we have used the}Bouligand-Minkowski fractal dimension. We applied these
descriptors to discriminate between two titanium oxide films prepared under
different experimental conditions. Results demonstrate the discrimination power
of proposed descriptors in such kind of application
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