Search results for " Regression"
showing 10 items of 1835 documents
Relationship between socioeconomic factors and intelligence of preschoolers: A cohort study in the Serbian context
2020
The aim of the current research is to analyse the relationship between the socioeconomic status (SES) of parents and intellectual abilities (IQ) of preschool children of Serbian territory, and in particular how SES factors relate to preschool children’s IQ measured with Raven’s Coloured Progressive Matrices (CPM), in the different age groups. The research included 430 parents and 430 preschool children. A confirmatory factor analysis of the SES questionnaire revealed five factors: educational and professional status of father and mother, residential and educational status of the family, sport status of parents and comfort of family housing. No gender differences in IQ levels were found in c…
Análisis de la realidad sociolingüística del valenciano
2011
Se analiza la situación actual del uso y la percepción social del valenciano entre los habitantes del País Valenciano a partir de los estudios realizados por el Centro de Investigaciones Sociológicas. Para ello, se presta especial atención a variables sociodemográficas a partir de análisis estadístico multivariante con distribuciones de frecuencias bivariadas, análisis de segmentación y regresión logística. El estudio concluye que se produce un estancamiento en el porcentaje de hablantes del valenciano y que las personas de izquierdas y con mayor nivel de estudios son quienes se postulan más a favor de la unidad del valenciano con el catalán. Palabras clave: sociolingüística; diglosia; esta…
Predictors of time famine among Finnish employees - Work, family or leisure?
2009
The recent survey data indicates that the time famine is a common experience among employees, while the data of time use indicates increased leisure time. Similarly, there are different views on the causes of time famine. Firstly, in working life research time famine is usually explained by increasing requirements of work life. Secondly, in gender studies time famine is considered to be a product of family obligations. Thirdly, some authors interpret time famine as a phenomenon relating to the intensification of leisure. The aim of the study was to examine the extent and causes of time famine among Finnish employees. The analysis was based on the Finnish Use of Time data (1999–2000) and foc…
What keeps young adults in permanent poverty? A comparative analysis using ECHP
2009
Abstract Previous studies suggest that there are strong differences in the rates of youth poverty across European countries. Rather surprisingly, it is found to be high in Scandinavian countries, and relatively speaking, lower in Mediterranean and Anglo-Saxon countries. This somewhat unexpected finding prompts the question whether the incidence of poverty is an appropriate measure of youth disadvantage. Instead of considering poverty rates we consider the length of recorded poverty spells, taking into account explicitly the temporal sequencing of the episodes of poverty. Using the European Community Household Panel, individuals are classified into different groups of poverty permanence, eac…
A spectroscopic method for determining lignin content of softwood and hardwood kraft pulps
1998
Abstract A rapid method for determining the kappa number of unbleached and oxygen-delignified kraft pulps in the range 3–35 is presented. This novel method was based on the multivariate analysis of VIS spectral data on pulp samples. The calculated models and the test results indicated that partial least squares (PLS) and principal component regression (PCR) models yielded similar results, PLS being slightly more accurate. It was also found that for practical purposes a separate model for each wood feedstock and delignification process is needed.
FTIR Monitoring of Chemical Changes in Softwood During Heating
2000
Abstract A multivariate chemometric method for monitoring the mass loss of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) by IR spectroscopic determination of chemical changes occurring during the heat treatment (160 - 260 °C, 2 - 8 h) of these wood materials was developed. The method was based on the handling of FTIR data on treated and untreated wood powder samples by the partial least squares (PLS) method. In addition, unknown samples (treated and untreated pine and spruce) were classified into separate groups by the principal component analysis (PCA) method. The chemical changes occurring in the wood samples during heating were also briefly discussed.
The Yearly Land Cover Dynamics (YLCD) method: An analysis of global vegetation from NDVI and LST parameters
2009
NDVI (Normalized Difference Vegetation Index) has been widely used to monitor vegetation changes since the early eighties. On the other hand, little use has been made of land surface temperatures (LST), due to their sensitivity to the orbital drift which affects the NOAA (National Oceanic and Atmospheric Administration) platforms flying AVHRR sensor. This study presents a new method for monitoring vegetation by using NDVI and LST data, based on an orbital drift corrected dataset derived from data provided by the GIMMS (Global Inventory Modeling and Mapping Studies) group. This method, named Yearly Land Cover Dynamics (YLCD), characterizes NDVI and LST behavior on a yearly basis, through the…
Integrating geophysical and geostatistical techniques to map the spatial variation of clay
2012
Abstract The development of subsoil models represents an important aspect of land resource evaluation, because they can provide an accurate description of the spatial variability in soil properties. Although direct soil sampling provides the best information in terms of soil properties, sample density is rarely adequate to accurately describe the horizontal and vertical variability of the physical properties of soil. Geophysical methods, such as Ground Penetrating Radar (GPR) and electromagnetic induction (EMI) sensors, provide rapid, non-invasive and exhaustive ways for subsoil characterization. Moreover, geophysical methods can be integrated with geostatistics to map soil properties. This…
Optimization criteria in sample selection step of local regression for quantitative analysis of large soil NIRS database
2012
International audience; Large soil spectral libraries compiling thousands of NIR (Near Infrared) reflectance spectra have been created encompassing a wide diversity and heterogeneity of spectra. Among the many chemometric approaches to the calibration of chemical and physical properties from these large libraries, local calibrations have the advantage of being able to select the most similar spectra to the spectrum of a target sample. This is particularly relevant when dealing with highly heterogeneous media such as soils, where the mineral matrix has a strong influence on spectral features. A crucial step in the implementation of local calibration procedures is the construction of local ne…
A simplified approach to estimate water retention for Sicilian soils by the Arya-Paris model
2014
Application of the Arya and Paris (AP) model to estimate the soil water retention curve requires a detailed description of the particle-size distribution (PSD) because the scale factor a, relating the pore length of an ideal soil to that of the natural one, depends on the particle size distribution parameters. For a dataset of 140 Sicilian soils that were grouped in five texture groups, the logistic and linear models were applied to evaluate a, and the water retention values predicted by the AP model were compared with the measured ones. Using the parameters proposed by Arya et al. (1999), the two models yielded similar unsystematic root mean error of estimate (RMSEu). Therefore, their pote…