Control of Discrete-event Systems provides a survey of the most important topics in the discrete-event systems theory with particular focus on finite-state automata, Petri nets and max-plus algebra. Coverage ranges from introductory material on the basic notions and definitions of discrete-event systems to more recent results. Special attention is given to results on supervisory control, state estimation and fault diagnosis of both centralized and distributed/decentralized systems developed in the framework of the Distributed Supervisory Control of Large Plants (DISC) project. Later parts of the text are devoted to the study of congested systems though fluidization, an over approximation allowing a much more efficient study of observation and control problems of timed Petri nets. Finally, the max-plus algebraic approach to the analysis and control of choice-free systems is also considered. Control of Discrete-event Systems provides an introduction to discrete-event systems for readers that are not familiar with this class of systems, but also provides an introduction to research problems and open issues of current interest to readers already familiar with them. Most of the material in this book has been presented during a Ph.D. school held in Cagliari, Italy, in June 2011.

M. Silva Significant changes have been occurring in industrialized countries since the Second World War. Production is moving towards sophisticated high qUality products, economy of scale has been replaced by economy of scope, jerky demands are progressively replacing steady demands, and competi tiveness is becoming a worldwide phenomenon. These trends require highly automated manufacturing systems with small set-up times and high flex ibility. As a consequence, implementation and running costs of modem manufacturing systems are drastically increasing, whereas their fields of application remain limited, and every day become even narrower, which increases the risk of early obsolescence. This is the reason why designers are trying to improve the preliminary design phase, also known as the 'paper study phase'. The preliminary design phase includes, but is not limited to, the func tional specification, and the evaluation of the system. Many tools exist to support the functional specification of manufactur ing systems. IDEFO is one of these tools. It leads, using a top-down ap proach, to a precise functional description of the required system. However, its use cannot be extended further. In general, the evaluation starts with a modeling step, which depends on the evaluation tool used, and ends by applying the model to find out its main dynamic characteristics. Two main approaches can be used to perform this task, namely simulation and math ematical approach. Using simulation, the modeling tool is either a classical computer language, or a simulation language."

This volume contains the proceedings of the 19th annual International Conference on Application and Theory of Petri Nets. The aim of the Petri net conference is to create a forum for the dissemination of the latest results in the application and theory of Petri nets. It always takes place in the last week of June. Typically there are 150 - 200 participants. About one third of these come from industry while the rest are from universities and research institutions. The conferences and a number of other activities are coordinated by a steering committee with the following members: G. Balbo (Italy), J. Billington (Australia), G. DeMichelis(Italy),C. Girault(France),K. Jensen (Denmark), S. Kumagai (Japan), T. Murata (USA), C. A. Petri (Germany; honorary member), W. Reisig (Germany), G. Roucairol (France), G. Rozenberg (The Netherlands; chairman), M. Silva (Spain). The 19th conference has been organized for the rst time in Portugal, by the Department of Electrical Engineering of the Faculty of Sciences and Technology of the New University of Lisbon, together with the Center for Intelligent Robotics of UNINOVA. It takes place in Lisbon at the same time as EXPO'98, the last world exhibition of the 20th century.

Esta peque a obra es un di logo dirigido a ni os y ni as, y en el cual enlazo los Diez Mandamientos de Dios con temas de mis fil sofos favoritos: S crates, Ren Descartes, Friedrich Nietzsche, Conny M ndez y otros.
Soy de la opini n que en la Sagrada Biblia y ciertos libros de filosof a existen pensamientos de gran inspiraci n, y en los cuales se puede hallar tranquilidad y la superaci n personal. Y por qu no empezar con esta base a nuestros peque os?
Por lo contrario, nuestro tiempo e intereses propios nunca alcanzan para educar de manera personal a nuestros hijos; siempre tenemos excusas de ser padres muy ocupados. Y tantito peor, de manera indiferente aunque no mal intencionada, mejor permitimos que ellos se envicien en el mundo virtual del internet y el omnipresente texting, aunado a un terrible fanatismo a la tecnolog a de los I-pads, smart phones, el Wii, y dem s.
Mientras tanto, tristemente, los libros son relegados al olvido, abandonados y llenos de polvo en alg n estante, y eso es que si acaso algunos pocos existan en el hogar. Hasta las bibliotecas parecen haber desaparecido de nuestra cultura debido al famoso Google. El concepto del libro me parece haberse perdido.
Sin embargo, mi motivaci n principal en escribir esta peque a obra, adem?'s de regalar a mis seres queridos un libro, es hacer notar a mi bella nieta Cassandra y sobrinos, Liz, Ricardo, Fanny, M a y Azul, que Dios existe, y que adem?'s hay mentes sabias que hacen notar su sabidur a.
Quiz?'s algunos temas filos ficos sean algo complicados para una audencia tan joven, pero reto a los padres que se atrevan a leer con sus peque os el alcance de esta obra, y expliquen donde se requiera.
Por ltimo, este libro no es una sopa a cucharadas de religi n con sabor a metaf sica, y tampoco favorece alguna secta u organizacion religiosa; y mucho menos pretendo hacerme notar como un experto en el basto y complej simo universo de la filosof a. Es s lo una introducci n a los mandatos de Dios contrastados con la filosof a, y dirigido a nuestros peque os gigantes del futuro.
Manuel Silva Escalera
Marzo 2012 El Paso, Texas, E.U.A.

This is an EXACT reproduction of a book published before 1923. This IS NOT an OCR'd book with strange characters, introduced typographical errors, and jumbled words. This book may have occasional imperfections such as missing or blurred pages, poor pictures, errant marks, etc. that were either part of the original artifact, or were introduced by the scanning process. We believe this work is culturally important, and despite the imperfections, have elected to bring it back into print as part of our continuing commitment to the preservation of printed works worldwide. We appreciate your understanding of the imperfections in the preservation process, and hope you enjoy this valuable book.

This is a reproduction of a book published before 1923. This book may have occasional imperfections such as missing or blurred pages, poor pictures, errant marks, etc. that were either part of the original artifact, or were introduced by the scanning process. We believe this work is culturally important, and despite the imperfections, have elected to bring it back into print as part of our continuing commitment to the preservation of printed works worldwide. We appreciate your understanding of the imperfections in the preservation process, and hope you enjoy this valuable book.

En el presente trabajo de investigacion, trato de abordar como problema principal, la determinacion de la naturaleza juridica del contrato de servicios no personales; para lo cual esquematizo mi analisis en tres capitulos: el primero de ellos versa sobre los distintos regimenes de contratacion estatal de personas naturales. En el segundo capitulo, nos centramos en el estudio del contrato de servicios no personales, desde sus antecedentes historicos, pasando por su tratamiento legislativo en las sucesivas leyes anuales de presupuesto, la Ley N 28411, la Ley N 24041, la Ley de Contrataciones y Adquisiciones del Estado y su Reglamento, y las directivas dictadas por el Ministerio de Economia y Finanzas; asi como su tratamiento jurisprudencial. La tercera parte, a su vez, esta dedicada al analisis comparativo del contrato de servicios no personales con las modalidades contractuales estudiadas en el capitulo primero; de tal forma que logremos determinar la naturaleza juridica de este tipo de contrato."