Controllability of time-invariant singular linear systems

We consider triples of matrices (E; A;B), representing singular linear time invariant systems in the form Ex_ (t) = Ax(t) + Bu(t), with E;A 2 Mn(C) and B 2 Mn£m(C), under proportional and derivative feedback. Structural invariants under equivalence relation characterizing singular linear systems are used to obtain conditions for controllability of the systems.Postprint (published version

Analysis of behavior of the eigenvalues and eigenvectors of singular linear systems

Let E(p)x˙ = A(p)x + B(p)u be a family of singular linear systems smoothly dependent on a vector of real parameters p = (p1, . . . , pn). In this work we construct versal deformations of the given differentiable family under an equivalence relation, providing a special parametrization of space of systems, which can be effectively applied to perturbation analysis. Furthermore in particular, we study the behavior of a simple eigenvalue of a singular linear system family E(p)x˙ = A(p)x + B(p)u.Postprint (published version

Herramientas de álgebra lineal para la ingeniería. Problemas resueltos

Postprint (published version

Output observability of time-invariant singular linear systems

In this paper finite-dimensional singular linear discrete-time-invariant systems in the form Ex(k + 1) = Ax(k) + Bu(k), y(k) = Cx(k) where E;A 2 M = Mn(C), B 2 Mn£m(C), C 2 Mp£n(C), describing convolutional codes are considered and the notion of output observability is analyzed.Postprint (published version

Eigenstructure of of singular systems. Perturbation analysis of simple eigenvalues

The problem to study small perturbations of simple eigenvalues with a change of parameters is of general interest in applied mathematics. After to introduce a systematic way to know if an eigenvalue of a singular system is simple or not, the aim of this work is to study the behavior of a simple eigenvalue of singular linear system familyPostprint (published version

Perturbation analysis of simple eigenvalues of singular linear systems

In this work a study of the behavior of a simple eigenvalue of singular linear system family E ( p )_ x = A ( p ) x + B ( p ) u , y = C ( p ) x smoothly dependent on a vector of real parameters p = ( p 1 ;:::;p n ) is pre- sentedPostprint (published version

Perturbation analysis of eigenvalues of polynomial matrices smoothly depending on parameters

Polynomial matrix, Eigenvalues, Perturbation.Let P(¸) = Pk i=0 ¸iAi(p) be a family of monic polyomial matrices smoothly dependent on a vector of real parameters p = (p1; : : : ; pn). In this work we study behavior of a multiple eigenvalue of the monic polynomial family P(¸).Postprint (published version

Recycling of residual IGCC slags and their benefits as degreasers in ceramics

This work studies the evolution of IGCC slag grains within a ceramic matrix fired at different temperatures to investigate the effect of using IGCC slag as a degreaser. Pressed ceramic specimens from two clay mixtures are used in this study. The M1 mixture is composed of standard clays, whereas the M2 mixture is composed of the same clay mixture as M1 mixture but contains 15% by weight IGCC slag. The amount of IGCC slag added coincides with the amount of slag typically used as a degreaser in the ceramic industry. Specimens are fired at 950 ºC, 1000 ºC, 1050 ºC, 1100 ºC and 1150 ºC. The mineralogical composition and the IGCC slag grain shape within the ceramic matrix are determined by X-ray diffraction, polarized light microscopy and scanning electron microscopy. The results reveal that the surface of the slag grains is welded to the ceramic matrix while the quartz grains are separated, which causes increased water absorption and reduces the mechanical strength. IGCC slag, however, reduces water absorption. This behaviour is due to the softening temperature of the slag. This property is quite important from an industrial viewpoint because IGCC slag can serve as an alternative to traditional degreasing agents in the ceramic building industry. Additionally, using IGCC slag allows for the transformation of waste into a secondary raw material, thereby avoiding disposal at landfills; moreover, these industrial wastes are made inert and improve the properties of ceramics

Word Reading: the influence of phonological awareness and teaching methods

Phonological awareness and teaching methods implemented in the classroom can influence the development of early reading skills. Specifically, this paper aims at identifying which specific linguistic factors influence reading skills and how the context of classroom instruction can affect this learning process. Data have been collected from a sample composed of children belonging to the last year of Childhood Education of two different schools in Seville (State and Private schools) following a quantitative and qualitative methodology. On the one hand, tests related to the students' level of phonological awareness, speed naming and reading comprehension were carried out. On the other hand, interviews and observations to the teachers were conducted in order to get a deeper understanding of their teaching methods, activities and resources used inside the classroom. Results confirm that phonological awareness, letter and pseudo-word reading are strong predictors of word reading. Furthermore, students with a higher level of phonological awareness and reading have received formal instruction through a mixed teaching method combining the phonic and global method. It is evident that these students present a more advanced level of automation. In conclusion, this specific mixed teaching method undoubtedly favours children's reading development.La conciencia fonológica y el método de lectura usado en el aula pueden influir en el desarrollo de habilidades lectoras en edades tempranas. Este estudio tiene como objetivos principales determinar qué factores lingüísticos pueden influir en el aprendizaje lector y conocer el papel en que dicho aprendizaje juega el contexto de instrucción. Se han recogido datos a través de una metodología cuantitativa y cualitativa en una muestra compuesta por el alumnado del segundo ciclo de Educación Infantil de dos centros educativos de la provincia de Sevilla, uno público y otro privado. Se han realizado pruebas sobre el nivel de procesamiento fonológico, velocidad en denominación y nivel de lectura del alumnado participante, además de observaciones y entrevistas al profesorado para conocer su método de enseñanza de lectura, así como las actividades y los recursos utilizados en el aula. Los resultados muestran que el procesamiento fonológico y la lectura de letras y pseudopalabras son buenos predictores de la lectura de palabras. Además, los discentes que presentan un mayor nivel de conciencia fonológica y de lectura y han recibido instrucción formal, a partir de un método combinado fónico y global, muestran un grado más avanzado de automatización lectora. Concluimos que este método combinado favorece el desarrollo lector del alumnado