Necrológica / Obituary

 

Laura Recalde Frisón

Caparroso, Navarra, 1971 - Zaragoza, 2008

Universidad de Zaragoza
Profesora titular de Ingeniería de Sistemas y Automática en el Centro Politécnico Superior (CPS) de la Universidad de Zaragoza desde 2003, miembro del Grupo de Ingeniería de Sistemas de Eventos Discretos (GISED) del Instituto de Investigación en Ingeniería de Aragón (I3A) y del Departamento de Informática e Ingeniería de Sistemas (DIIS), nos ha dejado durante las pasadas fiestas navideñas. Fallecía el 27 de diciembre, tras una dura batalla que desde el mes de mayo entabló contra un difícil tercer y diferente episodio de cáncer.

Matemática de formación, le fue concedida una beca INTERCAMPUS/E.AL, lo que le permitió trabajar en Colombia en 1994, año en que se graduó con premio extraordinario en la Facultad de Ciencias. En ese mismo mes de octubre, inició su andadura como investigadora en el Grupo de Ingeniería de Sistemas de Eventos Discretos (GISED), en el marco de la ESPRIT Basic Research Action (EBRA) «Quantitative Modelling in Parallel Systems» (QMIPS), pasando a participar de inmediato y muy activamente en el Human Capital and Mobility, también financiado por la Unión Europea, sobre «Modelling and Analysis of Time Constrained and Hierarchical Systems» (MATCH). En 1998 se doctoró brillantemente en Ingeniería de Sistemas e Informática. Finalista para el premio extraordinario de la Universidad de Zaragoza, su tesis versó sobre el análisis y diseño de sistemas discretos concurrentes descritos con redes de Petri. Poco después evolucionó para comprender y controlar el comportamiento de las redes fluidas o fluidificadas, siendo co-directora de las tesis doctorales de Jorge Júlvez, sobre Algebraic Techniques for the Analysis and Control of Continuous Petri Nets (abril 2005), y Cristian Mahulea, sobre Timed Continuous Petri Nets: Quantitative Analysis, Observability and Control (septiembre 2008).

Profesora de cursos como Teoría de Sistemas, Control de Procesos Químicos y Sistemas de Eventos Discretos, ha participado en muy diversos proyectos nacionales e internacionales de investigación, en particular en tres acciones integradas, dos hispano-italianas (con las universidades de Turín, sobre métodos formales para la evaluación de prestaciones, y de Cagliari, sobre observabilidad y observadores, acción esta última de la que ha sido investigadora principal) y una hispano-francesa (PICASSO, con el LAAS/CNRS, sobre técnicas estructurales y modulares para el análisis de sistemas híbridos). La muerte le alcanzó cuando se contaba con su importante implicación en DISC, Distributed Supervisory Control of Complex Plants, un «Specific Targeted Research Project» (Unión Europea) que acaba de comenzar en el pasado septiembre.

Editora asociada del IEEE Transactions on Automation, Science and Engineering desde enero de 2006, ha actuado como revisora de artículos en revistas como Theoretical Computer Science, IEEE Transactions on Automatic Control, IEEE Transactions on Robotics and Automation, IEEE Transactions on Systems, Man, and Cybernetics o The Computer Journal. En seis ocasiones ejerció como miembro del IPC de la Int. Conf. on Application and Theory of Petri Nets (ICAT PN), en tres de los Int. Workshop on Petri Nets and Performance Models (PNPM, hoy integrados en QEST), en dos de los Int. Workshop on Discrete Event Systems (WODES, en los años 2002 y 2004), así como de otras muy diversas conferencias internacionales.

Su trabajo de investigación se ha centrado en el modelado de sistemas discretos y en el desarrollo de técnicas estructurales para su análisis y síntesis, línea característica del grupo en las que el estado inicial se considera de forma paramétrica, integrando conceptos y procedimientos de automática (estabilidad, controlabilidad, observabilidad, optimización dinámica…), informática (transformaciones, decidabilidad…) e investigación de operaciones (evaluación de prestaciones, optimización paramétrica…). Su rigor, su claridad de pensamiento y su extrema habilidad construyendo contraejemplos ante demostraciones de propiedades que «se resistían» han sido excepcionales.

Con un pequeño acento en su último año, se relaciona a continuación una reducida lista de sus trabajos que solo pretende ofrecer una primera impresión de sus dominios de interés (para una lista más completa: GISED).

Pero si Laura ha brillado singularmente como profesional, mucho más estimables han sido sus cualidades personales. Los que gozamos de la suerte de tratarla siempre hemos admirado su capacidad de lucha ante la adversidad y su tenacidad, lo que le ha permitido enfrentarse con entereza a circunstancias vitales muy difíciles, que la mayoría creemos insuperables. Sin duda, esto le hizo desarrollar una rara habilidad, la de saber concentrarse en las cosas positivas e importantes de la vida, en las que contribuyen a la felicidad, no solo personal, también la de su entorno. Singular ha sido también su coraje, el de quien, por ejemplo, con una pierna ortopédica ha subido en el Parque Nacional de Ordesa hasta la Cola de Caballo y bajado por la Senda de los Cazadores, ante la admiración de colegas y alumnos de muy diversos países. En fin, nunca podremos olvidar su curiosidad insaciable, su mesura, su entrañable cercanía, su hechizante sonrisa, tan frecuente, sincera y contagiosa. Por ello siempre estará viva entre nosotros. 		Associate Professor of Systems Engineering and Automatic Control at the University of Zaragoza since 2003, member of the Group of Discrete Event Systems Engineering (GISED), of the Aragón Institute for Engineering Research (I3A) and the Department of Computer Science and Systems Engineering (DIIS), has left us over the past holiday season. She passed away on December 27, after a tough battle since May against a difficult and different third episode of cancer.

As a student in mathematics, she received a scholarship INTERCAMPUS / E.AL, which allowed her to work in Colombia in 1994. In that year, she obtained her degree in mathematics with honours from the Faculty of Sciences in Zaragoza. In the same month of October, she began as a researcher at the GISED under the ESPRIT Basic Research Action (EBRA) "Quantitative Modelling in Parallel Systems” (QMIPS) taking immediately after a very active part in the Human Capital and Mobility, which was funded by the European Union on "Modelling and Analysis of Time Constrained and Hierarchical Systems” (MATCH). In 1998 she defended a brilliant Ph.D. thesis in Systems Engineering and Computer Science. Finalist for the special award from the University of Zaragoza, her thesis focused on the analysis and design of concurrent discrete systems described with Petri nets. Shortly after she evolved to understand and develop control techniques for fluid Petri nets. She was co-advisor of the Ph.D. thesis of Jorge Júlvez entitled Algebraic Techniques for the Analysis and Control of Continuous Petri Nets (April 2005), and Cristian Mahulea entitled Timed Continuous Petri Nets: Quantitative Analysis, Observability and Control (September 2008).

She was teacher in courses such as: System Theory, Control Systems of Chemical Processes, and Discrete Event Systems. She has participated in many different national and international research projects, particularly in three integrated actions, two Spanish-Italian (with the University of Turin, on formal methods for the performance evaluation of systems, and Cagliari on observability and observers, in which she was the coordinator) and a Spanish-French (PICASSO with LAAS / CNRS, on modular techniques for structural analysis of hybrid systems). She passed away when it was expected to play an important role in DISC, “Distributed Supervisory Control of Complex Plants”, a Specific Targeted Research Project (EU) which has just started last September.

Associate editor of the IEEE Transactions on Automation Science and Engineering since January 2006, she was reviewer for the following journals: Theoretical Computer Science, IEEE Transactions on Automatic Control, IEEE Transactions on Robotics and Automation, IEEE Transactions on Systems, Man, and Cybernetics and The Computer Journal. She served six times as an IPC member of the International Conference on Application and Theory of Petri Nets (ICATPN), three times of that of the International Workshop on Petri Nets and Performance Models (PNPM now integrated into QEST), twice of the International Workshop on Discrete Event Systems (WODES) and a wide variety of other international conferences.

Her research has focused on the modelling of discrete event systems and the development of techniques for structural analysis and synthesis. This is one of the main research lines of GISED in which the initial state is taken as a parameter in order to integrate different concepts and procedures of Automatic Control (stability, controllability, observability, dynamic optimization ...), Computer Science (transformations, decidability issues...) and Operations Research (performance evaluation, parametric optimization...). Her thoroughness, clarity of thought and her extreme ability to build counter-examples for tough properties have been exceptional.

In order to give an idea about her academic research, a small list of publications with some emphasis on her last year, is presented below (for a more complete list see: GISED).

Anyway, if Laura has shone particularly as a professional, much more remarkable are her personal qualities. We who were lucky of having dealt with her, we have always admired its ability to fight adversity, and its tenacity, which has enabled her to face with integrity difficult life circumstances, which many of us consider insurmountable. Undoubtedly, this made Laura develop an uncommon ability, to concentrate on the positive and important things in life, the ones which contribute to happiness, not only at personal level, but also for everyone around her. Its courage was so outstanding that, for example, she went up the Cola de Caballo in the Ordesa National Park and down by the Senda de los Cazadores with an orthopaedic leg, what caused the admiration of colleagues and students from different countries. Anyway, we can never forget its insatiable curiosity, moderation, endearing closeness and bewitching smile, so frequent, sincere and contagious. Therefore she always will be alive among us.
Co-autora con una quincena de colegas de España, Estados Unidos, Francia, Italia, México, Reino Unido, Rumania y Singapur, entre sus trabajos cabe mencionar: Co-author with some fifteen colleagues from France, Italy, Mexico, Romania, Singapore, Spain, United Kingdom, United States, among her works we can mention:
  • «Modelling and Análisis of Sequential Processes that cooperate through buffers» (IEEE Transactions on Robotics and Automation: 14/2: 267-277, 1998).
  • «On linear algebraic techniques for liveness analysis of P/T systems» (Journal of Circuits, Systems, and Computers, 8/1: 223-265, 1998).
  • «Autonomous Continuous PT systems» (Application and Theory of Petri Nets, Springer, LNCS, 1639: 107—126, 1999).
  • «Structure Theory of Multi-Level Deterministically Synchronized Sequential Processes» (Theoretical Computer Science, 254/1-2: 1-33, 2001).
  • «Petri Nets fluidification revisited: Semantics and Steady State» (APII-JESA, Hermes Science, 35/4: 435-449, 2001).
  • «Petri nets and integrality relaxations: A view of continuous Petri nets» (IEEE Trans. On Systems, Man, and Cybernetics. Part C, 32/4: 314 -327, 2002).
  • «A Deadlock Avoidance Approach for Non-Sequential Resource Allocation Systems» (IEEE Trans. on Systems, Man, and Cybernetics, 34/1: 93-101, 2004).
  • «Petri nets and manufacturing systems: An examples-driven tour» (Springer-Verlag, Lectures on Concurrency and Petri Nets, LNCS, vol. 3098: 742-788, 2004).
  • «On reachability in autonomous continuous Petri net systems» (Applications and Theory of Petri Nets,, Springer-Verlag, LNCS 2679: 221-240).
  • «On fluidification of Petri net models: from discrete to hybrid and continuous models» (Annual Reviews in Control, 28/2: 253-266, 2004).
  • «Steady-state performance evaluation of continuous mono-T-semiflow Petri nets» (Automatica, 41/4: 605-616, 2005).
  • «Deadlock-freeness analysis of continuous mono-T-semiflow Petri nets» (IEEE Trans. On Automatic Control, 51/9: 1472-1481, 2006).
  • «On sampling continuous timed Petri nets: reachability, “equivalente” under infinite servers semantics» (Analysis and Design of Irbid Systems, ADHS’06, pp. 37-43, 2006).
  • «On the computational power of Timed Differentiable Petri nets» (Formal Modeling and Analysis of Timed Systems, FORMATS 2006, Springer, LNCS, 4202: 230-244, 2006).
  • «Continuous Petri Nets: Expressive Power and Decidability Issues» (International Symposium on Automated Technology for Verification and Analysis, Springer, LNCS, 4762: 362-377, 2007).
  • «Redes de Petri Continuas: Expresividad, Análisis y Control de una Clase de Sistemas Lineales Conmutados» (Revista Iberoamericana de Automática e Informática Industrial, RIAI, 4/3: 5-33, 2007).
  • «Tracking Control of Join-Free Timed Continuous Petri Net Systems under Infinite Servers Semantics» (Journal of Discrete Event Dynamic Systems, 18/2: 263 – 283, 2008).
  • «Steady state control reference and token conservation laws in continuous Petri net systems» (IEEE Trans. on Automation Science and Engineering, 5/2: 307-320, 2008).
  • «On controllability of timed continuous Petri nets» (Hybrid Systems: Computational and Control, HSCC 2008, Springer, LNCS 4981: 528-541, 2008).
  • «Observability of Timed Continuous Petri nets: a class of Hybrid Systems» (IFAC World Congress, Seul, Korea, 2008).
  • «Timing and deadlock-freeness in Continuous Petri nets» (IFAC World Congress, Seul, Korea, 2008).
  • «Stochastic State-Continuous Approximation of Markovian Petri Nets Systems» (IEEE CDC’ 08, Cancun, México, 2008).
  • «Formal analysis of timed continuous Petri nets» (IEEE CDC’ 08, Cancun, México, 2008).
  • «On observability and design of observers in timed continuous Petri net systems» (IEEE Transactions on Automation Science and Engineering, 5/3: 532-537, 2008).
  • «Optimal model predictive control of Timed Continuous Petri nets» (IEEE Transactions on Automatic Control, 7/53: 1731–1735, 2008).
  • «Basic Server Semantics and Performance Monotonicity of Continuous Petri Nets», (Journal of Discrete Event Dynamic Systems, SpringerLink, sept. 2008).

A ti Laura

Palabras leídas por Manuel Silva en las honras fúnebres el 29 de diciembre de 2008.
Words read by Manuel Silva at the funeral the past December 29.

In memoriam of prof. Laura Recalde


Mensajes de condolencia / Condolence messages