Search results for "RETRIEVAL"
showing 10 items of 1176 documents
Self and N-2 collisional broadening of far-infrared methane lines measured at the SOLEIL synchrotron
2012
International audience; Following our recent study devoted to measurements of intensities of pure rotation lines of methane, room temperature far infrared spectra of methane diluted in nitrogen at five total pressures between 100 and 800 hPa have been recorded at the AILES beamline of the SOLEIL synchrotron. One hundred and five N-2 broadening coefficients of methane pure rotation lines have been measured in the 83-261 cm(-1) spectral range using multi-spectrum non-linear least squares fitting of Voigt profiles. Pressure-induced line shifts were not needed to fit the spectra to the noise level and line mixing effects were neglected. One hundred and seventy-six self broadening coefficients h…
Mechanochemical Synthesis of Sn(II) and Sn(IV) Iodide Perovskites and Study of Their Structural, Chemical, Thermal, Optical and Electrical Properties
2019
Phase‐pure CsSnI3, FASnI3, Cs(PbSn)I3, FA(PbSn)I3 perovskites (FA = formamidinium = HC(NH2)2+) as well as the analogous so‐called vacancy‐ordered double perovskites Cs2SnI6 and FA2SnI6 are mechanochemically synthesized. The addition of SnF2 is found to be crucial for the synthesis of Cs‐containing perovskites but unnecessary for hybrid ones. All compounds show an absorption onset in the near‐infrared (NIR) region, which makes them especially relevant for photovoltaic applications. The addition of Pb(II) and SnF2 is crucial to improve the electronic properties in 3D Sn(II)‐based perovskites, in particular their charge carriers mobility (≈0.2 cm2 Vs−1) which is enhanced upon reduction of the …
Quantitative phase imaging by single-shot Hilbert-Huang phase microscopy.
2016
We propose a novel single-shot Hilbert-Huang transform-based algorithm applied to digital holographic microscopy (DHM) for robust, fast, and accurate single-shot quantitative phase imaging in on-axis and off-axis configurations. Fringe pattern with possible defects and closed fringes are adaptively filtered and accurately phase demodulated using local fringe direction estimation. Experimental validation of the proposed techniques is presented as the DHM study of microbeads and red blood cells phase samples. Obtained results compare very favorably with the Fourier approach (off-axis) and temporal phase shifting (on-axis).
Resolution enhancement and orders separation in on-axis nanoparticles based digital holography
2013
A method for eliminating the unwanted terms in an on axis hologram is presented. Free randomly distributed nanoparticles are used to encode and later on to decode/separate the desired term from the unwanted aberrations.
Tabu search for the Max–Mean Dispersion Problem
2015
In this paper, we address a variant of a classical optimization model in the context of maximizing the diversity of a set of elements. In particular, we propose heuristics to maximize the mean dispersion of the selected elements in a given set. This NP-hard problem was recently introduced as the maximum mean dispersion problem (MaxMeanDP), and it models several real problems, from pollution control to ranking of web pages. In this paper, we first review the previous methods for the MaxMeanDP, and then explore different tabu search approaches, and their influence on the quality of the solutions obtained. As a result, we propose a dynamic tabu search algorithm, based on three different neighb…
Upper and lower bounds for the vehicle-routing problem with private fleet and common carrier
2019
Abstract The vehicle-routing problem with private fleet and common carrier (VRPPC) extends the capacitated VRP by considering the option of outsourcing customers to subcontractors at a customer-dependent cost instead of serving them with the private fleet. The VRPPC has important applications in small package shipping and manufacturing, but despite its relevance, no exact solution approach has been introduced so far. We propose a branch-price-and-cut algorithm that is able to solve small to medium-sized instances and provides tight lower bounds for larger instances from the literature. In addition, we develop a large neighborhood search that shows a decent solution quality and competitive r…
Bounded geometry, growth and topology
2010
We characterize functions which are growth types of Riemannian manifolds of bounded geometry.
Tunnel effect and symmetries for Kramers–Fokker–Planck type operators
2011
AbstractWe study operators of Kramers–Fokker–Planck type in the semiclassical limit, assuming that the exponent of the associated Maxwellian is a Morse function with a finite number n0 of local minima. Under suitable additional assumptions, we show that the first n0 eigenvalues are real and exponentially small, and establish the complete semiclassical asymptotics for these eigenvalues.
Use of Guided Regularized Random Forest for Biophysical Parameter Retrieval
2018
This paper introduces a feature selection method based on random forest -the Guided Regularized Random Forest (GRRF)- which can be used in classification and regression tasks. The method is based on the regularization of the information gain in the random forest nodes to obtain a subset of relevant and non-redundant features. The proposed method is used as a preliminary step In the process of retrieving biophysical parameters from a hyperspectral image. Preliminary experiments show that we can reduce the RMSE of the retrievals by around 7% for the Leaf Area Index and around 8% for the fraction of vegetation cover when compared to the results using random forest features.
A survey of serendipity in recommender systems
2016
We summarize most efforts on serendipity in recommender systems.We compare definitions of serendipity in recommender systems.We classify the state-of-the-art serendipity-oriented recommendation algorithms.We review methods to assess serendipity in recommender systems.We provide the future directions of serendipity in recommender systems. Recommender systems use past behaviors of users to suggest items. Most tend to offer items similar to the items that a target user has indicated as interesting. As a result, users become bored with obvious suggestions that they might have already discovered. To improve user satisfaction, recommender systems should offer serendipitous suggestions: items not …