http://hdl.handle.net/2117/3232 2013-06-18T22:51:15Z http://hdl.handle.net/2117/18256 Title: Convolutional codes under control theory point of view. Analysis of output-observability Authors: García Planas, María Isabel; Souidi, El Mamoun; Um, Laurence E. Abstract: In this work we make a detailed look at the algebraic structure of convolutional codes using techniques of linear systems theory. The connection between these concepts help to better understand the properties of convo- lutional codes, in particular the concepts of controllability and observability of linear systems can be translated into the context of convolutional codes relating these properties with the noncatastrophicity of the codes. We examine the output-observability property and we give conditions for this property. 2013-03-13T12:48:29Z http://hdl.handle.net/2117/18162 Title: Factorization of the transfer matrix of a singular linear systems Authors: García Planas, María Isabel; López Cabeceira, M. Montserrat Abstract: Given a linear dynamic time invariant represented by x + ( t ) = Ax ( t ) Bu ( t ) , y ( t ) = Cx ( t ) , we analyze con- ditions for obtention of a coprime factorization of trans- fer matrices of singular linear systems defined over commutative rings R with element unit. The problem presented is related to the existence of solutions of a matrix equation XE ° NXA = Z . 2013-03-11T08:34:20Z http://hdl.handle.net/2117/16880 Title: Learning automation to teach mathematics Authors: Ferrer Llop, Josep; Peña Carrera, Marta; Ortiz Caraballo, Carmen 2012-11-12T09:29:49Z http://hdl.handle.net/2117/15829 Title: Input Observability Analysis of Fixed Speed Wind Turbine Authors: García Planas, María Isabel; Domínguez García, José Luís; Mediano Valiente, Begoña Abstract: This paper deals with the concept of input observability in a fixed speed wind turbine. A linear system has been calculated from the nonlinear equations of the squirrel cage induction generator, supposing it connected directly to the grid and assuming a steady state operating point. The observability of the input from the output of the system could be an interesting way to know if its possible to develop some new controls without introduce special sensors in the system. Furthermore, it is interesting to analyse which is the parameter variation margin of the wind turbine from input-observable state to non-input observable, in order to obtain some restrictions to design future controllers, or limit the operating points. 2012-05-11T09:56:05Z http://hdl.handle.net/2117/14096 Title: Output observability of time-invariant singular linear systems Authors: García Planas, María Isabel; Tarragona Romero, Sonia Abstract: 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. 2011-11-28T11:24:26Z http://hdl.handle.net/2117/14095 Title: Solving disturbance decoupling for singular systems by p&d-feedback and p&d-output injection Authors: García Planas, María Isabel Abstract: Singular systems are an important class of systems from both point of view theoretical and practical. In this paper we analyze the problem of constructing feedbacks and/or output injections that suppress this disturbance in the sense that it does not affect the inputoutput behavior of the system and makes the resulting closed-loop system regular and of index at most one. All results are based on the canonical reduced forms that they can be computed using a complete system of invariants and can be implemented in a numerically stable way. 2011-11-28T11:19:02Z http://hdl.handle.net/2117/13231 Title: Perturbation analysis of eigenvalues of polynomial matrices smoothly depending on parameters Authors: García Planas, María Isabel; Tarragona Romero, Sonia Abstract: 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(¸). Description: Polynomial matrix, Eigenvalues, Perturbation. 2011-09-19T09:46:49Z http://hdl.handle.net/2117/11093 Title: Controllability of time-invariant singular linear systems Authors: García Planas, María Isabel; Tarragona Romero, Sonia; Díaz, Adolfo Abstract: 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 lin- ear systems are used to obtain conditions for controllability of the systems. 2011-01-18T16:04:43Z http://hdl.handle.net/2117/11079 Title: An alternative complete system of invariants for matrix pencils under strict equivalence Authors: García Planas, María Isabel; Díaz, Adolfo Abstract: 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 Mp£n(C) and B 2 Mn£m(C), un- der proportional and derivative feedback. Using geometrical techniques we obtain miniversal deformations that permit us to study sensivity and structural stability of singular systems. 2011-01-18T11:56:10Z http://hdl.handle.net/2117/11077 Title: Sensivity and stability of singular systems under proportional and derivative Authors: García Planas, María Isabel Abstract: 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 Mp£n(C) and B 2 Mn£m(C), un- der proportional and derivative feedback. Using geometrical techniques we obtain miniversal deformations that permit us to study sensivity and structural stability of singular systems. 2011-01-18T11:50:06Z http://hdl.handle.net/2117/8187 Title: Disturbance decoupling for singulars systems by proportional and derivate feedback and proportional and derivate outputm injection Authors: García Planas, María Isabel Abstract: We study the disturbance decoupling problem for linear time invariant singular systems. We give necessary and su±cient conditions for the existence of a solution to the disturbance decoupling problem with or without stability via a proportional and derivative feedback and proportional and derivative output injection that also makes the resulting closed-loop system regular and/or of index at most one. All results are based on canonical reduced forms that can be computed using a complete system of invariants that can be implemented in a numerically stable way. 2010-07-16T06:37:23Z http://hdl.handle.net/2117/833 Title: Linearization of local cohomology modules Authors: Álvarez Montaner, Josep; Zarzuela Armengou, Santiago Abstract: The aim of this work is to describe the linear structure of regular holonomic $\mathcal D$-modules with support a normal crossing with variation zero introduced in [Local cohomology, arrangements of subspaces and monomial ideals, to appear in Adv. in Math.] with special regard to the case of local cohomology modules supported on monomial ideals. 2007-05-02T15:57:27Z