Invariance principles for switched systems with restrictions

In this paper we consider switched nonlinear systems under average dwell time switching signals, with an otherwise arbitrary compact index set and with additional constraints in the switchings. We present invariance principles for these systems and derive by using observability-like notions some convergence and asymptotic stability criteria. These results enable us to analyze the stability of solutions of switched systems with both state-dependent constrained switching and switching whose logic has memory, i.e., the active subsystem only can switch to a prescribed subset of subsystems.Comment: 29 pages, 2 Appendixe

The influence of crack-imbalance orientation and orbital evolution for an extended cracked Jeffcott rotor

Vibration peaks occurring at rational fractions of the fundamental rotating critical speed, here named Local Resonances, facilitate cracked shaft detection during machine shut-down. A modified Jeffcott-rotor on journal bearings accounting for gravity effects and oscillating around nontrivial equilibrium points is employed. Modal parameter selection allows this linear model to represent first mode characteristics of real machines. Orbit evolution and vibration patterns are analyzed, yielding useful results. Crack detection results indicate that, instead of 1x and 2x components, analysis of the remaining local resonances should have priority; this is due to crack-residual imbalance interaction and to 2x multiple induced origins. Therefore, local resonances and orbital evolution around 1/2, 1/3 and 1/4 of the critical speed are emphasized for various crack-imbalance orientations

Moment tensor solutions for the Iberian-Maghreb region during the IberArray deployment (2009–2013)

AbstractWe perform regional moment tensor inversion for 84 earthquakes that occurred in the Iberian-Maghreb region during the second and third leg of IberArray deployment (2009–2013). During this period around 300 seismic broadband stations were operating in the area, reducing the interstation spacing to ~50km over extended areas. We use the established processing sequence of the IAG moment tensor catalogue, increasing to 309 solutions with this update. New moment tensor solutions present magnitudes ranging from Mw 3.2 to 6.3 and source depths from 2 to 620km. Most solutions correspond to Northern Algeria, where a compressive deformation pattern is consolidated. The Betic-Rif sector shows a progression of faulting styles from mainly shear faulting in the east via predominantly extension in the central sector to reverse and strike-slip faulting in the west. At the SW Iberia margin, the predominance of strike-slip and reverse faulting agrees with the expected transpressive character of the Eurasian-Nubia plate boundary. New strike-slip and oblique reverse solutions in the Trans-Alboran Shear Zone reflect its left-lateral regime. The most significant improvement corresponds to the Atlas Mountains and the surroundings of the Gibraltar Arc with scarce previous solutions. Reverse and strike-slip faulting solutions in the Atlas System display the accommodation of plate convergence by shortening in the belt. At the Gibraltar Arc, several new solutions were obtained at lower crustal and subcrustal depths. These mechanisms show substantial heterogeneity, covering the full range of faulting styles with highly variable orientations of principal stress axes, including opposite strike slip faulting solutions at short distance. The observations are not straightforward to explain by a simple geodynamic scenario and suggest the interplay of different processes, among them plate convergence in old oceanic lithospheric with large brittle thickness at the SW Iberia margin, as well as delamination of thickened continental lithosphere beneath the Betic-Rif arc

An Easy Laboratory Method for Optimizing the Parameters for the Mechanical Densification Process: An Evaluation with an Extruder

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 8 (2006): An Easy Laboratory Method for Optimizing the Parameters for the Mechanical Densification Process: An Evaluation with an Extruder. Manuscript PM 06 015. Vol. VIII. July, 2006

Strong exponential stability of switched impulsive systems with mode-constrained switching

Strong stability, defined by bounds that decay not only over time but also with the number of impulses, has been established as a requirement to ensure robustness properties for impulsive systems with respect to inputs or disturbances. Most existing results, however, only consider weak stability. In this paper, we provide a method for calculating the maximum overshoot and the decay rate for strong (and weak) global uniform exponential stability bounds for non-linear switched impulsive systems. We consider the scenario of mode-constrained switching where not all transitions between subsystems are allowed, and where subsystems may exhibit unstable dynamics in the flow and jump maps. Based on direct and reverse mode-dependent average dwell-time and activation-time constraints, we derive stability bounds that can be improved by considering longer switching sequences for computation. We provide numerical examples that illustrate the weak and strong exponential stability bounds and also how the results can be employed to ensure the stability robustness of nonlinear systems that admit a global state weak linearization.Comment: 23 pages, 4 figure

Historiografía musical de las parroquias en España: estado de la cuestión

Most of the studies carried out in Spain about religious music have taken the cathedrals and collegiate churches as their source of study, classifying and transcribing works, analyzing the musical resources of the centers, the circulation of interpreters among them, the way the ecclesiastical economy affected their music or the evolution and acceptance of the different styles. However, the musical study of the parish churches did not have the same success, although it was there where the works that most of the people listened were played and sometimes they had the material and human resources typical of churches with collegiate and even cathedral standing. So in this article it is covered the Spanish musical historiography about parish churches, determining the state of the topic and thus favoring future studies about the subject.La mayoría de los trabajos realizados en España sobre música religiosa han tomado como objeto de estudio las catedrales y colegiatas, catalogando y transcribiendo obras, analizando los recursos musicales de los centros, la circulación de intérpretes entre ellos, la forma en que la economía eclesiástica afectó a su música o la evolución y aceptación de los diferentes estilos. Sin embargo, el estudio musical de las iglesias parroquiales no ha tenido la misma suerte, a pesar de que era en éstas donde se interpretaban las obras que escuchaba la mayoría de la población y que, en ocasiones, dispusieron de recursos materiales y humanos propios de templos con rango colegial e incluso catedralicio. Por ello, en este artículo se hace un recorrido a la historiografía musical española sobre parroquias, determinando el estado de la cuestión y favoreciendo así la realización de futuros estudios sobre el tema

La Música, pero también Música: nuevos cánones de Tomás de Iriarte

Tomás de Iriarte has gone down in history as one of the most important Spanish Neoclassicism writers. Beyond, he contributed to the theory of sound art in the 18th century with his didactic poem La música. However, Iriarte was also an amateur player of instruments like the viola and he had important activity as a composer. In spite of this, until now we only know the music of his melologist Guzmán el Bueno and a collection of seventeen canons. These canons are preserved in a source of the Superior Music Conservatory of Madrid and they have been published only a decade ago. Nevertheless, in this research, we present another oldest and most complete canons collection than the aforementioned. It is unpublished to date and it contains more than twenty works different from those collected in the Madrid source.Tomás de Iriarte ha pasado a la historia como uno de los escritores más relevantes del neoclasicismo español, pero también por haber contribuido decididamente a la teoría del arte de los sonidos en el siglo XVIII con su poema didáctico La música. No obstante, también fue un intérprete aficionado de instrumentos como la viola y desarrolló una significativa actividad como compositor, aunque hasta el momento solo se conozca la música de su melólogo Guzmán el Bueno y una colección de diecisiete cánones, estos últimos conservados en una fuente del Conservatorio Superior de Música de Madrid publicada hace solo una década. Sin embargo, en este trabajo de investigación damos a conocer otra colección de cánones más antigua y completa que la citada, inédita hasta la fecha, que contiene una veintena más de obras distintas a las recogidas en la fuente madrileña

Propuestas para la atención a la diversidad del alumnado de Educación Secundaria Obligatoria de Andalucía en música a través de la optatividad

Este artículo estudia la atención a la diversidad como uno de los principios básicos del sistema educativo español y, en consecuencia, también de la educación en la Comunidad Autónoma de Andalucía. En concreto, a lo largo del trabajo se hacen diversas propuestas para atender a la diversidad del alumnado ofertando materias optativas de música en los cuatro cursos de la Educación Secundaria Obligatoria, de forma que se dé respuesta a las necesidades educativas específicas y a los intereses y expectativas de los alumnos/as