2 resultados para Time-dependent variables
em Universidade Complutense de Madrid
Resumo:
There is a growing concern about the poor quality of the writing of children and teenagers because of the continuous and constant exposure to the new technologies. Increasingly parents complain that their children spend too much time with their phones, tablets, computers, video games, etc. There is also an increase in the number of teachers who complain about their students’ writing skills. Some of the most prominent criticisms are loss of vocabulary, simplified syntax and the poor spelling of the compositions. To verify if these criticisms are motivated or not by the use of information and communication technologies (ICT) is what moved us to initiate this doctoral dissertation entitled “The influence of ICT on ratings of syntactic maturity: a comparative study between pre- and post-internet generations”. We aim to know if a daily and constant exposure to the ICT can affect the syntactic maturity rates of children and teenagers. We also want to find out if there are differences between the levels of syntactic maturity of today’s students and those of the 1990s, when there were no ICT and internet. In order to do this, we have carried out a quantitative analysis taking as a reference previous studies by generativist researchers in the Anglo-Saxon and Hispanic world and we have used the same units of measure (T-unit and clause). We collected a corpus of 382 essays, half argumentative and half descriptive, from 191 individuals. We have analyzed them according to ten dependent variables or syntactic maturity rates and other independent variables (Hours in internet, Course, Sex, Location, Type of school) by applying techniques of descriptive and inferential statistics...
Resumo:
Photothermal imaging allows to inspect the structure of composite materials by means of nondestructive tests. The surface of a medium is heated at a number of locations. The resulting temperature field is recorded on the same surface. Thermal waves are strongly damped. Robust schemes are needed to reconstruct the structure of the medium from the decaying time dependent temperature field. The inverse problem is formulated as a weighted optimization problem with a time dependent constraint. The inclusions buried in the medium and their material constants are the design variables. We propose an approximation scheme in two steps. First, Laplace transforms are used to generate an approximate optimization problem with a small number of stationary constraints. Then, we implement a descent strategy alternating topological derivative techniques to reconstruct the geometry of inclusions with gradient methods to identify their material parameters. Numerical simulations assess the effectivity of the technique.