Search results for "Data type"
showing 10 items of 1183 documents
Thermal–infrared emissivities of natural surfaces: improvements on the experimental set-up and new measurements
2003
Ground measurements of thermal infrared emissivities of terrestrial surfaces are required to derive accurate temperatures from radiometric measurements, and also to apply and validate emissivity models using satellite sensor observations. This paper focuses on the demanding aspects that are involved in the field measurement of emissivity using the box method and a hand-held radiometer. Measuring emissivities in field conditions can be hampered by external factors such as wind and solar irradiance. This can increase the time spent on the field campaign but, most importantly, it can cause no-sense fluctuations between consecutive observations. Here we propose original developments for the exp…
ChemInform Abstract: Topologically Complex Molecules Obtained by Transition Metal Templation: It Is the Presentation that Determines the Synthesis St…
2013
Topological constructions made from closed curves range from simple links to intricate knots and started to capture the chemists' attention in the early sixties. These mathematical objects result from particular embeddings of a single or a set of closed curves in the three-dimensional space that show an infinite variety of presentations. Simple catenanes, higher order interlocked macrocycles, and molecular knots can be synthesized via the metal template approach, just as simple macrocycles. However, this requires that rigid presentations with appropriate geometrical characteristics be identified prior to molecular design, and those selected for the metal-templated synthesis of some of these…
Two-Sided Estimates of the Solution Set for the Reaction–Diffusion Problem with Uncertain Data
2009
We consider linear reaction–diffusion problems with mixed Dirichlet–Neumann–Robin conditions. The diffusion matrix, reaction coefficient, and the coefficient in the Robin boundary condition are defined with an uncertainty which allow bounded variations around some given mean values. A solution to such a problem cannot be exactly determined (it is a function in the set of “possible solutions” formed by generalized solutions related to possible data). The problem is to find parameters of this set. In this paper, we show that computable lower and upper bounds of the diameter (or radius) of the set can be expressed throughout problem data and parameters that regulate the indeterminacy range. Ou…
Regression with Imputed Covariates: A Generalized Missing Indicator Approach
2011
A common problem in applied regression analysis is that covariate values may be missing for some observations but imputed values may be available. This situation generates a trade-off between bias and precision: the complete cases are often disarmingly few, but replacing the missing observations with the imputed values to gain precision may lead to bias. In this paper we formalize this trade-off by showing that one can augment the regression model with a set of auxiliary variables so as to obtain, under weak assumptions about the imputations, the same unbiased estimator of the parameters of interest as complete-case analysis. Given this augmented model, the bias-precision trade-off may then…
Validation of a temperature emissivity separation hybrid method from airborne hyperspectral scanner data and ground measurements in the SEN2FLEX fiel…
2008
This paper presents an assessment of the performance of a hybrid method that allows a simultaneous retrieval of land-surface temperature (LST) and emissivity (LSE) from remotely-sensed data. The proposed method is based on a synergistic usage of the split-window (SW) algorithm and the two-temperature method (TTM) and combines the advantages of both procedures while mitigating their drawbacks. The method was implemented for thermal channels 76 (10.56 µm) and 78 (11.72 µm) of the Airborne Hyperspectral Scanner (AHS), which was flown over the Barrax test site (Albacete, Spain) in the second week of July 2005, within the framework of the Sentinel-2 and Fluorescence Experiment (SEN2FLEX) field c…
Comparison of theory and experiment
1991
In this section we are finally going to confront experimental data on total cross section, angular distributions and polarization observables with theoretical results in order to establish the present status of our knowledge of this important process. We hope this will enable us to set directions and guidelines for future experimental and theoretical studies, which kind of experiments are needed and what accuracy should be aimed for, where theoretical studies should be extended, on what they should focus and whether some basic assumptions need to be modified. For the comparison we shall use mostly the data of experiments selected in sections 6.3 and 6.4, the relative quantities and the best…
On Using “Stochastic Learning on the Line” to Design Novel Distance Estimation Methods
2018
In this paper, we consider the problem of Distance Estimation (DE) when the inputs are the x and y coordinates of the points under consideration. The aim of the problem is to yield an accurate value for the real (road) distance between the points specified by the latter coordinates. This problem has, typically, been tackled by utilizing parametric functions called Distance Estimation Functions (DEFs). The parameters are learned from the training data (i.e., the true road distances) between a subset of the points under consideration. We propose to use Learning Automata (LA)-based strategies to solve the problem. In particular, we resort to the Adaptive Tertiary Search (ATS) strategy, propose…
Looking Beyond Genres: Identifying Meaningful Semantic Layers from Tags in Online Music Collections
2011
A scheme for identifying the semantic layers of music-related tags is presented. Arguments are provided why the applications of the tags cannot be effectively pursued without a reasonable understanding of their semantic qualities. The identification scheme consists of a set of filters. The first is related with social consensus, user-count ratio, and n-gram properties of tags. The next relies on look-up functions across multiple databases to determine the probable semantic layer of each tag. Examples of the semantic layers with prevalence rates are given based on application of the scheme to a subset of the Million Song Dataset. Finally, a validation of the results was carried out with an i…
Application of adaptive models for the determination of the thermal behaviour of a photovoltaic panel
2013
The use of reliable forecasting models for the PV temperature is necessary for a more correct evaluation of energy and economic performances. Climatic conditions certainly have a remarkable influence on thermo-electric behaviour of the PV panel but the physical system is too complex for an analytical representation. A neural-network-based approach for solar panel temperature modelling is here presented. The models were trained using a set of data collected from a test facility. Simulation results of the trained neural networks are presented and compared with those obtained with an empirical correlation.
Springback Evaluation In Basic Sheet Metal Stamping Processes
2000
In the present paper a measurement technique based on the shadow moire method has been set up in order to evaluate the springback phenomenon in deep drawing operations. Two proper coefficients are introduced to quantitatively describe the effect considered. In particular the proposed technique is able to acquire the final profile of the drawn parts along one or more generatrices, once extracted out from the dies and to compare such profile with the ideal one derived from the dies CAD geometry. The proposed technique has been applied to an axysimmetrical deep drawing operation and moreover the influence of the blankholder force level and of the lubricating conditions have been taken into acc…