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101.
Simone Fiori 《Neural Processing Letters》2007,25(3):187-198
Neural independent component learning algorithms based on optimization on manifolds have attracted interest in the neural
network community. In the past years, we have developed learning algorithms specialized for the orthogonal group of matrices
as parameters manifold. Here, we sketch a view of these algorithms by the help of ‘retractions’ on manifolds. 相似文献
102.
Vittorio Sgrigna Francesco Altamura Simone Ascani Roberto Battiston Raffaele Bencardino Sandor Blasko Aurora Buzzi Marco Casolino Livio Conti Stefano Lucidi Mauro Minori Andrea Papi Piergiorgio Picozza Stefano Rossi Carlo Stagni David Zilpimiani 《Microgravity science and technology》2007,19(5-6):70-74
EGLE is a wide frequency band search- coil magnetometer designed and built at the Roma Tre University. It has been installed onboard the ISS by the Italian astronaut Roberto Vittori on April 25, 2005 within the LAZIO- EGLE experiment carried out during the ENEIDE Soyuz mission. The scope of the experiment is to test EGLE in space and to investigate geomagnetic field variations. The main applications of EGLE are the study of electromagnetic environment inside the ISS, the correlation of magnetic field data with particle fluxes detected by LAZIO particle detector, and the monitoring of ionospheric perturbations possibly caused by Earth seismic activity. Since continuous electromagnetic field measurements on board the ISS are important for diverse space applications, a magnetometer with a suitable design is requested. Appropriate solutions for these applications, which have been adopted by EGLE, are in particular the use of 1- Wire technology and the possibility to detect by means of a search- coil magnetometer a large portion of the ULF frequency band, usually measured by flux- gate probes. To investigate the topside ionosphere electromagnetic environment and stability of Van Allen radiation belts in relation with seismic and anthropogenic electromagnetic emissions, a specific satellite mission (the ESPERIA project) has been designed for the Italian Space Agency (ASI), and up to now a few instruments of its payload have been built and tested in space. One of them is exactly the EGLE search- coil magnetometer. The first magnetic observations performed by this instrument reveal to be promising and demand for a further and deeper analysis based on a longer time series of data. 相似文献
103.
Leticia Rittner Jennifer S. W. Campbell Pedro F. Freitas Simone Appenzeller G. Bruce Pike Roberto A. Lotufo 《Journal of Mathematical Imaging and Vision》2013,45(3):214-226
Diffusion tensor imaging (DTI) is a powerful technique for imaging axonal anatomy in vivo and its automatic segmentation is important for quantitative analysis and visualization. Application of the watershed transform is a recent approach for robustly segmenting diffusion tensor images. Since an important step of the watershed-based segmentation is the gradient computation, this paper investigates scalar maps from DTI and their ability to enhance borders and, therefore, their usefulness in gradient calculation. A comparison between existing scalar maps is conducted in the context of segmentation. New diffusion scalar maps, inspired by mathematical morphology concepts are proposed and included in the comparison. The watershed transform is then applied to segment the corpus callosum, based on the computed scalar maps. 相似文献
104.
105.
Novella Bartolini Tiziana Calamoneri Emanuele Guido Fusco Annalisa Massini Simone Silvestri 《Wireless Networks》2010,16(3):607-625
Mobile sensor networks are important for several strategic applications devoted to monitoring critical areas. In such hostile
scenarios, sensors cannot be deployed manually and are either sent from a safe location or dropped from an aircraft. Mobile
devices permit a dynamic deployment reconfiguration that improves the coverage in terms of completeness and uniformity. In
this paper we propose a distributed algorithm for the autonomous deployment of mobile sensors called Push & Pull. According
to our proposal, movement decisions are made by each sensor on the basis of locally available information and do not require
any prior knowledge of the operating conditions or any manual tuning of key parameters. We formally prove that, when a sufficient
number of sensors are available, our approach guarantees a complete and uniform coverage. Furthermore, we demonstrate that
the algorithm execution always terminates preventing movement oscillations. Numerous simulations show that our algorithm reaches
a complete coverage within reasonable time with moderate energy consumption, even when the target area has irregular shapes.
Performance comparisons between Push & Pull and one of the most acknowledged algorithms show how the former one can efficiently
reach a more uniform and complete coverage under a wide range of working scenarios. 相似文献
106.
FLOQUET-MUHR Laurence DURAND-BOURLIER Laurence TONDEUR Daniel CHANEL Simone 《Drying Technology》2013,31(9):2325-2341
Abstract A method making use of a gas chromatograph was investigated to acquire bound solvent drying rates. The solid to be dried was used as stationary phase in a chromatographic column, and the TCD detector was used to follow the decrease of solvent content of the effluent as inert gas was flown through the column. The measurement of the break-through curve allows the evolution of drying rate with time or solvent content to be obtained. The comparison of the experimental results with numerical simulation leads to the determination, through parametric adjustment, of the internal mass-transfer coefficient as a function of the solvent content during the second stage of bound solvent drying period. This parameter can lead to the value of the diffusivity as a function of solvent content. 相似文献
107.
108.
Voltage-contrast scanning electron microscopy is demonstrated as a new technique to locate and characterize defects in single-walled carbon nanotubes. This method images the surface potential along and surrounding a nanotube in device configuration and it is used here to study the following: (a) structural point-defects formed during nanotube growth, (b) nano-scale gap formed by high-current electrical breakdown, (c) electronic defect such as electron-irradiation induced metal-insulator transition, and (d) charge injection into the substrate which causes hysteresis in nanotube devices. The in situ characterization of defect healing under high bias is also shown. The origin of voltage-contrast, the influence of the above defects on the contrast profiles and optimum imaging conditions are discussed. 相似文献
109.
Chiara Bignardi Monica Mattarozzi Andrea Penna Simone Sidoli Lisa Elviri Maria Careri Alessandro Mangia 《Food Analytical Methods》2013,6(4):1144-1152
Enhanced sensitivity for the simultaneous determination of five nut allergens in biscuit and in dark chocolate complex matrices was obtained by introduction of a rapid size-exclusion solid-phase extraction-based step before liquid chromatography–electrospray ionization-tandem mass spectrometry (LC-ESI-MS2) analysis. A very fast and efficient separation (<12 min) of marker peptides with selected reaction monitoring detection was obtained. Limits of detection in the 0.1–1.3 mg nut/kg and 5–15 mg nut/kg ranges for biscuit and dark chocolate samples as well as high recoveries (84(±6)–106(±4)% for biscuits and 98(±5)–108(±6)% for dark chocolate) proved the excellent capabilities of the exploited sample treatment method combined with the LC-MS2 analysis. Good precision in terms of intra- and inter-day repeatability was calculated, being always lower than 19 % (n?=?75). Linearity was demonstrated up to four and three orders of magnitude for biscuit and dark chocolate, respectively. Finally, the validated method was successfully applied to the investigation of hidden nut trace allergens in commercially available biscuits and chocolates of different brands aiming to ascertain possible discrepancies between allergen content and food allergen labelling. 相似文献
110.
This study examined three visual strategies for timing the initiation of the landing flare based on perceptions of either: (a) a critical height above ground level; (b) a critical runway width angle (Ψ); or (c) a critical time-to-contact (TTC) with the runway. Visual displays simulated landing approaches with trial-to-trial variations in glideslope, lighting, and scene detail. Twenty-four participants (8 private pilots, 8 student pilots, and 8 nonpilots) were instructed to initiate the flare when they perceived that their TTC with the runway (30 m wide by 840 m long) had reached a critical value of 2 seconds. Our results demonstrated a significant effect of flight experience on flare timing accuracy and dominance of the height-based strategy over the runway-width-angle and TTC-based strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献