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On May 23–25, 2011, a workshop took place at the DIMACS Cen-ter at Rutgers University to cele-

brate the accomplishments of Eduardo D. Sontag on the occasion of his 60th birthday. The organizers of the work-shop were Murat Arcak from the Uni-versity of California, Berkeley, a close collaborator of Eduardo’s, Patrick De Leenheer from the University of Flori-da, a former postdoc, and Yuan Wang, from Florida Atlantic University, a for-mer Ph.D. student.

Eduardo D. Sontag was born in Buenos Aires on April 16, 1951. His father Bruno Sontag, who passed away one month after the workshop, was a jeweler who immigrated to Argentina in 1938 from Vienna at the age of 11, immediately after the Anschluss and thus barely escaping the Nazi death camps. His mother Sofia was born in Argentina from Eastern European par-ents. His wife Fran is retired from the IT industry, and his daughter Laura and son David, born on the 4th of July in 1982 and 1984, respectively, have Ph.D.s from MIT in systems biology and computer science, respectively.

Eduardo received the Licenciado degree in mathematics from the Uni-versity of Buenos Aires in 1972, with a thesis on algebraic theory of linear systems and automata, and a pub-lished book on artificial intelligence. Upon graduation, he was invited by Rudolf Kalman to become a graduate student at the University of Florida, where he defended his Ph.D. thesis on algebraic systems theory in December 1976. Since 1977, Eduardo has been a faculty member at Rutgers, the State University of New Jersey, with the rank of professor II (distinguished) since 1990. He is also a member of the

graduate faculties of the Department of Computer Science and the Depart-ment of Electrical and Computer Engi-neering, a cofounder and member of the Advisory Committee of the Bio-MaPS Institute for Quantitative Biol-ogy, the director of the undergraduate biomathematics major, and a member of the Cancer Institute of New Jersey at the Robert Wood Johnson Medical School. He was the recipient of the SIAM’s Reid Prize in Applied Math-ematics in 2001, the IEEE Control Sys-tems Society’s Bode Lecture Prize in 2002, and the IEEE Control Systems Award in 2011, as well as two major prizes from Rutgers, namely, the Board of Trustees Award for Excel-lence in Research in 2002 and the Scholar/Teacher Award in 2005.

Eduardo has had an impact on systems and control theory since his thesis on algebraic-geometric meth-ods in nonlinear observability and realization theory and his work, also started as a graduate student, on lin-ear control systems over rings. In a 1982 paper in IEEE Transactions in Automatic Control, he developed a formalism for the analysis of hybrid

controllers that combines continuous variables and discrete mathemat-ics with computer science and logic tools. In related work, he applied computational complexity ideas in a proof of the NP-hardness of check-ing nonlinear controllability. In 1981, in collaboration with his colleague Hector Sussmann, he obtained basic results on discontinuous stabiliza-tion. In 1989 he formulated the notion of input-to-state stability (ISS) and developed universal formulas for sta-bilization based on control Lyapunov functions.

During the 1990s, Eduardo and his students and collaborators contrib-uted to computational learning the-ory and neural networks, formulated a theory of analog computational complexity, designed methods based on nonsmooth analysis for feedback stabilization, obtained Lie-theoretic characterizations of controllability of discrete-time nonlinear systems, provided an approach to stabiliza-tion with saturated actuators, stud-ied the optimal control of robotic systems, and developed theoretical foundations of ISS and its variants.

Perspectives and Future Directions in Systems and Control TheoryA WORKSHOP IN HONOR OF EDUARDO D. SONTAG

Digital Object Identifier 10.1109/MCS.2011.942559 Date of publication: 11 November 2011

Eduardo Sontag (center) with former Ph.D. students (from left) German Enciso, Liming Wang, Madalena Chaves, Brian Ingalls, Renee Koplon, Misha Krichman, and Yuan Wang (coorganizer of workshop).

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Starting in 2000, a large part of Eduardo’s research effort has focused on molecular systems biology, with contributions to reverse engineer-ing of signaling pathways and gene and protein networks in living cells, a collaboration with David Angeli on monotone i/o systems, and work on unraveling the dynamical complexity of biochemical cellular networks. He also contributed to graph-theoretic bioinformatics algorithms for ana-lyzing transcription factor binding

and network structure, as well as the quantification of robustness of biolog-ical networks. The workshop presen-tations reflected many of Eduardo’s past and present research interests.

The workshop’s invited partici-pants were junior, mid-career, and senior researchers in the fields of sys-tems and control, signal processing, and systems biology, including Eyad Abed, Frank Allgower, David Angeli, Thanos Antoulas, Zvi Artstein, John Baras, Vincent Blondel, Peter Caines,

Madalena Chaves, Yacine Chitour, Jean-Michel Coron, Munther Dahleh, Domitilla DelVecchio, German Enciso, Jim Ferrell, Tryphon Georgiou, Lars Gruene, Bill Helton, Joao Hespanha, Moe Hirsch, Pablo Iglesias, Bronislaw Jakubczyk, Matthias Kawski, Mustafa Khammash, Pramod Khargonekar, Art Krener, Miroslav Krstic, Gerardo Lafferriere, Yuri Ledyaev, Naomi Leonard, Daniel Liberzon, Steve Marcus, Nuno Martins, Sanjoy Mit-ter, Steve Morse, Dragan Nesic, Pablo

Attendees of the workshop honoring Eduardo Sontag.

Eduardo Sontag (center) with his daughter Laura, wife Frances, son David, and their spouses Matt (left) and Violeta (right).

Eduardo with (from left) Jean-Michel Coron, Yacine Chitour, and Hector Sussmann.

Roger Brockett, Pramod Khargonekar, Jan Willems, Thanos Antoulas, and Yutaka Yamamoto.

Eduardo with current Ph.D. students Michael de Freitas, Zahra Aminzare, and Maja Skataric.

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Parrilo, Bozenna Pasik-Duncan, Jack Rugh, Rodolphe Sepulchre, Hal Smith, Hector Sussmann, Andy Teel, Jan van-Schuppen, M. Vidyasagar, Liming Wang, Jan Willems, and Yutaka Yama-moto. The total of about 100 attendees also included graduate students from several institutions, many of whom presented posters, as well as addi-tional former students and research collaborators of Eduardo’s.

The workshop consisted of half-hour lectures as well as spirited and some-

times controversial discussion panels on theoretical challenges, new application areas, and control education. The top-ics covered in the lectures represented a cross section of theoretical fields, from well-established areas (sampled-data control and signal processing, control of PDEs, hybrid and switched systems, singular perturbations, model reduction, model predictive control, nonlinear stabi-lization, monotone systems, differential-geometric aspects of nonlinear control systems), to emerging application direc-

tions, such as systems biology (models of the cell cycle, biological adaptation, chemotaxis, stochastic and deterministic modeling and analysis of biochemical networks, noise attenuation in molecu-lar biology signaling pathways, gene regulatory networks, synthetic biology), social networks, swarming and flocking in animal behavior, systems-theoretic ap -proaches to optimization, and the rela-tions between computation, control, and information theory. On the two days fol-lowing the formal workshop, about two

(From left) Murat Arcak (workshop coorganizer), Dragan Nesic, Nuno Martins, and Lars Gruene.Frank Allgower, Andy Teel, and Joao Hespanha.

Vincent Blondel, Pablo Parillo, and Munther Dahleh.Jack Rugh and Eduardo Sontag.

Tryphon Georgiou, Rodolphe Sepulchre, and Murat Arcak. Rodolphe Sepulchre and Miroslav Krstic.

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dozen participants stayed on for infor-mal discussion sessions, on topics rang-ing from automated traffic management and models of cell movement to control under actuator saturation.

Social occasions included group dinners on Sunday through Thursday, with a formal banquet on Tuesday night that was hosted by Yutaka Yama-

moto and featured personal remarks by many of Eduardo’s colleagues and former students.

A grant from the National Science Foundation is gratefully acknowl-edged for support of travel and local expenses for junior research-ers, graduate students, and invited participants. The workshop Web

site http://dimacs.rutgers.edu/ Workshops/ControlTheory has com-plete information, including the final program and slides of most of the presentations.

Yuan WangFlorida Atlantic University

David Angeli, Jean-Michel Coron, and Hal Smith. Zvi Artstein, Frank Allgower, and Peter Caines.

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