28 research outputs found
Denoising strategies for general finite frames
Overcomplete representations such as wavelets and windowed Fourier expansions have become mainstays of modern statistical data analysis. In the present work, in the context of general finite frames, we derive an oracle expression for the mean quadratic risk of a linear diagonal de-noising procedure which immediately yields the optimal linear diagonal estimator. Moreover, we obtain an expression for an unbiased estimator of the risk of any smooth shrinkage rule. This last result motivates a set of practical estimation procedures for general finite frames that can be viewed as the generalization of the classical procedures for orthonormal bases. A simulation study verifies the effectiveness of the proposed procedures with respect to the classical ones and confirms that the correlations induced by frame structure should be explicitly treated to yield an improvement in estimation precision
automatic and noninvasive indoor air quality control in hvac systems
This paper presents a methodology for assessing and monitoring the cleaning state of a heating, ventilation, and air conditioning (HVAC) system of a building. It consists of a noninvasive method for measuring the amount of dust in the whole ventilation system, that is, the set of filters and air ducts. Specifically, it defines the minimum amount of measurements, their time table, locations, and acquisition conditions. The proposed method promotes early intervention on the system and it guarantees high indoor air quality and proper HVAC working conditions. The effectiveness of the method is proved by some experimental results on different study cases
Phase Information and Space Filling Curves in Noisy Motion Estimation
Abstract This paper presents a novel approach for translational motion estimation based on the phase of the Fourier Transform. It exploits the equality between the averaging of a group of successive frames and the convolution of the reference one with an impulse train function. The use of suitable space filling curves allows to reduce the error in motion estimation making the proposed approach robust under noise. Experimental results show that the proposed approach outperforms available techniques in terms of objective (PSNR) and subjective quality with a lower computational effort. Edics: MDE-TRNS, MDE-OTH
Hydrolyzed rice formula. an appropriate choice for the treatment of cow’s milk allergy
Cow’s milk allergy (CMA) is a common condition in the pediatric population. CMA can induce a diverse range of symptoms of variable intensity. It occurs mainly in the first year of life, and if the child is not breastfed, hypoallergenic formula is the dietary treatment. Extensively hydrolyzed cow’s milk formulas (eHF) with documented hypo-allergenicity can be recommended as the first choice, while amino acid-based formulas (AAF) are recommended for patients with more severe symptoms. Hydrolyzed rice-based formulas (HRFs) are a suitable alternative for infants with CMA that cannot tolerate or do not like eHF and in infants with severe forms of CMA. In the present paper, we reviewed the nutritional composition of HRFs as well as studies regarding their efficacy and tolerance in children, and we provided an updated overview of the recent evidence on the use of HRFs in CMA. The available studies provide evidence that HRFs exhibit excellent efficacy and tolerance and seem to be adequate in providing normal growth in healthy children as well as in children with CMA
178Hg and asymmetric fission of neutron-deficient pre-actinides
International audienceFission at low excitation energy is an ideal playground to probe the impact of nuclear structure on nuclear dynamics. While the importance of structural effects in the nascent fragments is well established in the (trans-)actinide region, the observation of asymmetric fission in several neutron-deficient pre-actinides can be explained by various mechanisms. To deepen our insight into that puzzle, an innovative approach based on inverse kinematics and an enhanced version of the VAMOS++ heavy-ion spectrometer was implemented at the GANIL facility, Caen. Fission of Hg178 was induced by fusion of Xe124 and Fe54. The two fragments were detected in coincidence using VAMOS++ supplemented with a new SEcond Detection arm. For the first time in the pre-actinide region, access to the pre-neutron mass and total kinetic energy distributions, and the simultaneous isotopic identification of one the fission fragment, was achieved. The present work describes the experimental approach, and discusses the pre-neutron observables in the context of an extended asymmetric-fission island located southwest of Pb208. A comparison with different models is performed, demonstrating the importance of this new asymmetric-fission island for elaborating on driving effects in fission
Shape coexistence in neutron-deficient Hg-188 investigated via lifetime measurements
Shape coexistence in the region has been established in
mercury, lead and polonium isotopes. Even-even mercury isotopes with present multiple fingerprints of this phenomenon, which seems to be
no longer present for . According to a number of theoretical
calculations, shape coexistence is predicted in the Hg isotope. The
Hg nucleus was populated using two different fusion-evaporation
reactions with two targets, Gd and Gd, and a beam of S,
provided by the Tandem-ALPI accelerators complex at the Laboratori Nazionali di
Legnaro. The channels of interest were selected using the information from the
Neutron Wall array, while the rays were detected using the GALILEO
-ray array. The lifetimes of the excited states were determined using
the Recoil Distance Doppler-Shift method, employing the dedicated GALILEO
plunger device. Using the two-bands mixing and rotational models, the
deformation of the pure configurations was obtained from the experimental
results. The extracted transition strengths were compared with those calculated
with the state-of-the-art symmetry-conserving configuration-mixing (SCCM) and
five-dimentional collective Hamiltonian (5DCH) approaches in order to shed
light on the nature of the observed structures in the Hg nucleus. An
oblate, a normal- and a super-deformed prolate bands were predicted and their
underlying shell structure was also discussed.Comment: v1: 13 pages, 10 figures, comparison between IBM-CM and SCCM
calculations; v2: 16 pages, 13 figures, discussion on the mixing amplitudes
from the experimental B(E2) values, comparison between SCCM and 5DCH
calculation
Time-scale energy based analysis of contours of real-world shapes
This paper presents a novel approach for the local analysis of the contour of a planar real world shape. The 1D representation of that contour is a very complicated signal with several non isolated and oscillating singularities, which represent the micro-structure of the shape. The analysis of such a signal is usually difficult because of the presence of spurious phenomena in its time-scale representation, typical of oscillating singularities. The aim of the proposed model is to exploit the time-scale behavior of the energy of wavelet coefficients to extract a particular sequence of scales where those spurious phenomena are strongly reduced. The locality of the wavelet transform is then used to segment the contour into meaningful subregions, in agreement with their local spectral properties. Experimental results show that the proposed model overcomes some limits of existing methods for the analysis of real-world shapes micro-structur