Search results for " Depth"

3D shape extraction of internal and external surfaces of glass objects

2013

Three-dimensional (3D) digitization of manufactured objects has been investigated for several years and consequently, many techniques have been proposed. Even if some techniques have been successfully commercialized, most of them assume a diffuse or near diffuse reflectance of the object’s surface, and difficulties remain for the acquisition of “optically non cooperative” surfaces, such as transparent or specular ones. To address such surfaces, we propose a non conventional technique, called “Scanning from Heating” (SfH). In contrast to classical active triangulation techniques that acquire the reflection of visible light, we measure the thermal emission of the heated surface. The aim of th…

Relationship between vegetation microwave optical depth and cross-polarized backscatter from multiyear Aquarius observations

2017

Soil moisture retrieval algorithms based on passive microwave remote sensing observations need to account for vegetation attenuation and emission, which is generally parameterized as vegetation optical depth (VOD). This multisensor study tests a new method to retrieve VOD from cross-polarized radar backscattering coefficients. Three years of Aquarius/SAC-D data were used to establish a relationship between the cross-polarized backscattering coefficient σ HV and VOD derived from a multitemporal passive dual-channel algorithm (VODMT). The dependence of the correspondence is analyzed for different land use classes. There are no systematic differences in the slope for woody versus nonwoody vege…

Nitrous oxide fluxes from permafrost regions

2020

This dataset is a synthesis of published nitrous oxide (N2O) fluxes from permafrost-affected soils in Arctic, Antarctic, and Alpine permafrost regions. The data includes mean N2O flux rates measured under field (in situ) conditions and in intact plant-soil systems (mesocosms) under near-field conditions. The dataset further includes explanatory environmental parameters such as meteorological data, soil physical-chemical properties, as well as site and experimental information. Data has been synthesized from published studies (see 'Further details'), and in some cases the authors of published studies have been contacted for additional site-level information. The dataset includes studies publ…

Unexpected vertical structure of the Saharan Air Layer and giant dust particles during AER-D

2018

The Saharan Air Layer (SAL) in the summertime eastern Atlantic is typically well mixed and 3–4 km deep, overlying the marine boundary layer (MBL). In this paper, we show experimental evidence that at times a very different structure can be observed. During the AERosol properties – Dust (AER-D) airborne campaign in August 2015, the typical structure described above was observed most of the time, and was associated with a moderate dust content yielding an aerosol optical depth (AOD) of 0.3–0.4 at 355 nm. In an intense event, however, an unprecedented vertical structure was observed close to the eastern boundary of the basin, displaying an uneven vertical distribution and a very …

L’innovazione tecnologica e il Faculty Development.

2023

La crisi pandemica ha accelerato la diffusione di ambienti di apprendimento caratterizzati dall'uso intensivo della tecnologia. Questa novità rappresenta un obiettivo trasversale della professionalizzazione del docente universitario, con una particolare declinazione sul versante pedagogico-didattico-valutativo quale questione strategica per lo sviluppo dell’alta formazione. Il contributo illustra i risultati di una ricerca condotta con 119 docenti universitari neoassunti e 20 Direttori di dipartimento. La finalità della ricerca è stata, da una parte, rilevare la percezione dei docenti neoassunti relativa alle proprie competenze didattiche, metacognitive e valutative, con riferimento alla di…

Time-of-flight - Energy spectrometer for elemental depth profiling - Jyväskylä design

2014

Abstract A new time-of-flight elastic recoil detection spectrometer has been built, and initially the main effort was focused in getting good timing resolution and high detection efficiency for light elements. With the ready system, a 154 ps timing resolution was recorded for scattered 4.8 MeV 4 He 2+ ions. The hydrogen detection efficiency was from 80% to 20% for energies from 100 keV to 1 MeV, respectively, and this was achieved by having an additional atomic layer deposited Al 2 O 3 coating on the first timing detector’s carbon foil. The data acquisition system utilizes an FPGA-card to time-stamp every time-of-flight and energy event with 25 ns resolution. The different origins of the ba…

Improvement of time-of-flight spectrometer for elastic recoil detection analysis

2013

Sample–tip coupling efficiencies of the photon-scanning tunneling microscope

1991

The photon-scanning tunneling microscope is the photon analog to the electron-scanning tunneling microscope. It uses the evanescent field due to the total internal reflection of a light beam in a prism, modulated by a sample attached to the prism. The exponential decay of the evanescent field is characterized by the penetration depth dp and depends on the angle of incidence θ, the wavelength, and the polarization of the incident beam. The 1/e decay lengths range from 150 to 265 nm as deduced from the expression of the electric-field intensity in the rarer medium for θ = π/2. If we place another optically transparent medium near the surface, frustrated total reflection occurs. It is shown th…

Fuzzified Tree Search in Real Domain Games

2011

Fuzzified game tree search algorithm is based on the idea that the exact game tree evaluation is not required to find the best move. Therefore, pruning techniques may be applied earlier resulting in faster search and greater performance. Applied to an abstract domain, it outperforms the existing ones such as Alpha-Beta, PVS, Negascout, NegaC*, SSS*/ Dual* and MTD(f). In this paper we present experimental results in real domain games, where the proposed algorithm demonstrated 10 percent performance increase over the existing algorithms.

Column-integrated aerosol optical properties in the free troposphere: case study-Sierra Nevada, Spain

2004

From spectral solar irradiance extinction measurements in the visible range carried out at Sierra Nevada (2950 m a.s.l.) during July 1998, the characteristics of the aerosol column in the free troposphere have been measured. The results show that in stable atmospheric conditions, the column-integrated aerosol takes an optical depth (AOD) at 500 nm of 0.02 /spl plusmn/ 0.02, and an average radius in the accumulation mode of 0.15 /spl mu/m, with a likely Atlantic origin. In unstable situations, the AOD at 500 nm can increase by more than an order of magnitude, and the aerosols' origin is uncertain, since air masses can arrive from different sources at different altitudes.