Search results for " edge"
showing 10 items of 226 documents
A red-edge spectral index for remote sensing estimation of green LAI over agroecosystems
2013
Abstract Leaf area index (LAI) is a key biophysical parameter for the monitoring of agroecosystems. Conventional two-band vegetation indices based on red and near-infrared relationships such as the normalized difference vegetation index (NDVI) are well known to suffer from saturation at moderate-to-high LAI values (3–5). To bypass this saturation effect, in this work a robust alternative has been proposed for the estimation of green LAI over a wide variety of crop types. By using data from European Space Agency (ESA) campaigns SPARC 2003 and 2004 (Barrax, Spain) experimental LAI values over 9 different crop types have been collected while at the same time spaceborne imagery have been acquir…
Tools, Human Development and Mathematics
2016
This chapter raises a number of issues from pre-history and history that one mathematics educator considers ‘worthy of mention’ with regard to tools and mathematics. These issues are: tool use in the development of the human species (phylogenesis); tool use in a mathematical culture, ancient Greek mathematics that goes beyond the obvious tools; an example from ancient Indian mathematics that bears some resemblances to Jon’s experimental mathematics described in Chap. 3; the mutual support of hand, mind and artefact in expert use of an abacus; a consideration of a period (sixteenth-century Europe) where there was a rapid advance in the development of mathematical tools.
An Automatic Three-Dimensional Fuzzy Edge Detector
2009
Three-dimensional object analysis is of particular interest in many research fields. In this context, the most common data representation is boundary mesh, namely, 2D surface embedded in 3D space. We will investigate the problem of 3D edge extraction, that is, salient surface regions characterized by high flexure. Our automatic edge detection method assigns a value, proportional to the local bending of the surface, to the elements of the mesh. Moreover, a proper scanning window, centered on each element, is used to discriminate between smooth zones of the surface and its edges. The algorithm does not require input parameters and returns a set of elements that represent the salient features …
Editorial: Activation, functions, and generation of immunological memory in γδ T lymphocytes: lessons from nonhuman primates
2014
T cells constitute an unconventional lymphocyte population with distinct functions complementary to those of CD4 and CD8 T cells. As such, they have both adaptive features, such as expression of the TCR, and innate-like functions reminiscent of NK cells, with whom they share extensive repertoires of activating and inhibitory receptors [1, 2]. Although most antigens recognized by murine T cells remain obscure, advances have been made in identifying ligands for human T cells. The majority of circulating human T lymphocytes expresses a TCR formed by the preferentially-paired V 9 and V 2 chains (here and thereafter, called V 9V 2 T cells). Instead of binding peptides associated with molecules b…
Popolamenti marginali di faggio e cambiamenti climatici: criticità dell’applicazione di pratiche colturali classici in ambiente mediterraneo (Sicilia)
2013
Il faggio (Fagus sylvatica) è tra le specie forestali più importanti d’Europa per distribuzione, selvicoltura, rilevanza paesaggistica. Il faggio in Sicilia raggiunge il limite meridionale del proprio areale, nonché le quote altitudinali più elevate in Europa (timberline intorno a 2000 s.l.m.), localizzandosi sui Monti Nebrodi, Madonie ed Etna. La maggior parte di questi soprassuoli è stata tradizionalmente governata a ceduo semplice matricinato, seppur raramente all’interno di un quadro di interventi pianificati di lungo periodo, e molti popolamenti recentemente hanno subito primi interventi di avviamento alla conversione a fustaia. L’assetto attuale di questi soprassuoli è tuttavia destin…
X-ray absorption near edge spectroscopy at the Mn K-edge in highly homogeneous GaMnN diluted magnetic semiconductors
2006
We have studied by X-ray absorption spectroscopy the local environment of Mn in highly homogeneous Ga 1-x Mn x N (0.06 <x<0.14) thin epilayers grown by molecular beam epitaxy on [0001] SiC substrates. The measurements were performed in fluorescence mode around the Ga and Mn K-edges. In this report, we focus our attention to the X-ray absorption near edge spectroscopy (XANES) results. The comparison of the XANES spectra corresponding to the Ga and Mn edges indicates that Mn is substitutional to Ga in all samples studied. The XANES spectra measured at the Mn absorption edge shows in the near-edge region a double peak and a shoulder below the absorption edge and the main absorption peak after …
Energy-Efficient Edge Computing Service Provisioning for Vehicular Networks: A Consensus ADMM Approach
2019
In vehicular networks, in-vehicle user equipment (UE) with limited battery capacity can achieve opportunistic energy saving by offloading energy-hungry workloads to vehicular edge computing nodes via vehicle-to-infrastructure links. However, how to determine the optimal portion of workload to be offloaded based on the dynamic states of energy consumption and latency in local computing, data transmission, workload execution and handover, is still an open issue. In this paper, we study the energy-efficient workload offloading problem and propose a low-complexity distributed solution based on consensus alternating direction method of multipliers. By incorporating a set of local variables for e…
Decremental 2- and 3-connectivity on planar graphs
1996
We study the problem of maintaining the 2-edge-, 2-vertex-, and 3-edge-connected components of a dynamic planar graph subject to edge deletions. The 2-edge-connected components can be maintained in a total ofO(n logn) time under any sequence of at mostO(n) deletions. This givesO(logn) amortized time per deletion. The 2-vertex- and 3-edge-connected components can be maintained in a total ofO(n log2n) time. This givesO(log2n) amortized time per deletion. The space required by all our data structures isO(n). All our time bounds improve previous bounds.
Structural-relaxation phenomena in As–S glasses as probed by combined PAL/DBAR technique
2015
Abstract Experimental techniques exploring phenomena of positron–electron interaction, namely the positron annihilation lifetime spectroscopy and Doppler broadening of annihilation radiation, are shown to be very informative tools to study radiation- and thermally-induced phenomena in chalcogenide glasses of binary As–S system. Time-dependent processes of free-volume voids agglomeration (expansion), fragmentation (refining) and disappearing (contraction) are identified as main stages of physical aging in S-rich glasses, while a competitive channel of coordination topological defects formation associated with void charging becomes significant in a vicinity of near-stoichiometric glass compos…
Transient attosecond soft-X-ray spectroscopy in layered semi-metals (Conference Presentation)
2020
X-ray absorption fine-structure (XAFS) spectroscopy is a well-established technique capable of extracting information about a material’s electronic and lattice structure with atomic resolution. While the near-edge region (XANES) of a XAFS spectrum provides information about the electronic configuration, structural information is extracted from the extended XAFS (EXAFS) spectrum, consisting of several hundreds of eV above the absorption edge. With the advent of high harmonic sources, reaching photon energies in soft x-ray (SXR) region, it now becomes possible to connect the spectroscopic capabilities of XAFS to the unprecedented attosecond temporal resolution of a high harmonic source allowi…