Search results for "Combination"
showing 10 items of 1379 documents
A revision of Helichrysum panormitanum s.l. (Asteraceae) in the Italian and Maltese floras
2016
As part of the ongoing researches on Asteraceae for the new edition of the Italian Flora, a revision of Helichrysum panormitanum s.l. is presented here. On the basis of previously published morphological and chemical data, as well as our morphological and chorological observations, we hereby propose to recognize six subspecies under H. panormitanum: subsp. panormitanum, subsp. stramineum, subsp. brulloi subsp. nov., subsp. messeriae, subsp. latifolium, and subsp. melitense comb. nov. All these taxa are endemic to Sicily and Egadi Islands (Italy), except H. panormitanum subsp. melitense which is endemic to Gozo island (Maltese archipelago). A diagnostic key for the six accepted subspecies is…
SVM approximation for real-time image segmentation by using an improved hyperrectangles-based method
2003
A real-time implementation of an approximation of the support vector machine (SVM) decision rule is proposed. This method is based on an improvement of a supervised classification method using hyperrectangles, which is useful for real-time image segmentation. The final decision combines the accuracy of the SVM learning algorithm and the speed of a hyperrectangles-based method. We review the principles of the classification methods and we evaluate the hardware implementation cost of each method. We present the combination algorithm, which consists of rejecting ambiguities in the learning set using SVM decision, before using the learning step of the hyperrectangles-based method. We present re…
Revisitation of Nonorthogonal Spin Adaptation in Coupled Cluster Theory.
2015
The benefits of what is alternatively called a nonorthogonally spin-adapted, spin-free, or orbital representation of the coupled cluster equations is discussed relative to orthogonally spin-adapted, spin-orbital, and spin-integrated theories. In particular, specific linear combinations of the orbital cluster amplitudes, denoted spin-summed amplitudes, are shown to reduce the number of contractions that must be explicitly performed and to simplify the expressions and their derivation. The computational efficiency of the spin-summed approach is discussed and compared to orthogonally spin-adapted and spin-integrated approaches. The spin-summed approach is shown to have significant computationa…
Experimental validation for spectrum cartography using adaptive multi-kernels
2017
This paper validates the functionality of an algorithm for spectrum cartography, generating a radio environment map (REM) using adaptive radial basis functions (RBF) based on a limited number of measurements. The power at all locations is estimated as a linear combination of different RBFs without assuming any prior information about either power spectral densities (PSD) of the transmitters or their locations. The RBFs are represented as centroids at optimized locations, using machine learning to jointly optimize their positions, weights and Gaussian decaying parameters. Optimization is performed using expectation maximization with a least squares loss function and a quadratic regularizer. …
''Investigating reduction of dimensionality during single-joint elbow movements: a case study on muscle synergies''
2013
Chiovetto, Enrico | Berret, Bastien | Delis, Ioannis | Panzeri, Stefano | Pozzo, Thierry; International audience; ''A long standing hypothesis in the neuroscience community is that the central nervous system (CNS) generates the muscle activities to accomplish movements by combining a relatively small number of stereotyped patterns of muscle activations, often referred to as" muscle synergies." Different definitions of synergies have been given in the literature. The most well-known are those of synchronous, time-varying and temporal muscle synergies. Each one of them is based on a different mathematical model used to factor some EMG array recordings collected during the execution of variety…
Concerted Evolution of Multigene Families and Homoeologous Recombination
2012
The dynamism of genomes is one of the most thoroughly documented paradigms in the genomic era, envisaged by the cytogenetic school during middle decades of the twentieth century. Such dynamism refers not just to the evolutionary changes that take place across deep time but also to the myriad changes at different levels (from SNPs to large structural rearrangements) that shape and adjust genomes over a smaller time scale. This chapter reviews two of the many forces that provide genome dynamism in plants. These two forces, concerted evolution of multigene families and homoeologous recombination of hybridized genomes, in principle contribute to shape the plant genomes through opposite effects …
LCAO calculation of neutral defects in GaN
2005
Four well known HF, LDA, GGA and B3LYP Hamiltonians in LCAO approximation have been used in band structure calculations to obtain the main properties of the perfect GaN crystal with hexagonal lattice (C space group). Calculated lattice parameters, elastic constants and the band gap have been compared with the experimental data and the results of other calculations. As a consequence, the GGA Hamiltonian has been chosen, giving the lattice parameters a = 3.20 A, c = 5.20 A, u = 0.377, the bulk modulus B = 206 GPa and the energy gap Eg = 2.7 eV. These results reasonably reproduce the experimental data. For the point defects calculation (VGa, VN, MgGa, ZnGa, CN, and SiN) the supercell model was…
Exciton recombination dynamics in InAs∕InP self-assembled quantum wires
2005
In this work we investigate the exciton recombination dynamics in InAs∕InP semiconductor self-assembled quantum wires, by means of continuous wave and time resolved photoluminescence. The continuous wave photoluminescence results seem to indicate that the temperature quenching of the emission band seems to be more probably due to unipolar thermal escape of electrons towards the InP barrier. On the other hand, the analysis of time resolved photoluminescence reveals that the temperature dependence of the radiative and nonradiative recombination times is mainly determined by the dynamics of excitons localized by disorder (high energy tail of the PL band) and strongly localized (low energy tail…
Self-trapped exciton formation through photo-induced recombination of F and H centers in alkali iodides
1997
The photo-induced conversion of the primary F, H center pairs into self-trapped excitons have been proposed and studied in alkali iodides.
Formation of self-trapped excitons through stimulated recombination of radiation-induced primary defects in alkali halides
1998
Abstract A self-trapped exciton formation through photostimulated recombination of an F and an H center — the exciton-created primary defect pair, is proposed and experimentally examined in alkali halides at low temperatures.