ieee control systems magazinemaeweb.ucsd.edu/sites/mae.ucsd.edu/files/jorge+mac...four ieee fellows...

4 IEEE CONTROL SYSTEMS MAGAZINE » AUGUST 2014

24 APPLICATIONS OF CONTROL Leak Localization in Water Networks

37 PEOPLE IN CONTROL Jorge Cortés Ali Jadbabaie William “Mac” M. McEneaney Anna G. Stefanopoulou

98 HISTORICAL PERSPECTIVES Reflections on My Involvement with the CSS

100 BOOKSHELF Book Announcements

107 CONFERENCE REPORT International Workshop on Smart City:

Control and Automation Perspectives

112 CONFERENCE CALENDAR

114 CSS BUSINESS Consent Agenda of the IEEE Control Systems Society

Board of Governors Meeting

118 ON THE LIGHTER SIDE Chicken or Fish?

120 RANDOM INPUTS Past and Future ACCs

» D E PA R T M E N T S

MISSION STATEMENT AND SCOPE: As the official means of communication for the IEEE Control Systems Society, IEEE Control Systems Magazine publishes interesting, useful, and informative material on all aspects of control system technology for the benefit of control educators, practitioners, and researchers. With this mission statement in mind, IEEE Control Systems Magazine encour-ages submissions, both feature articles and columns, on all aspects of control system technology. SUBMISSION OF MANUSCRIPTS: A feature article typically provides an in-depth treatment of either an application of control tech-nology, a tutorial on some area of control theory, or an innovation in control education.

IEEE Control Systems Magazine publishes a variety of columns. “Applications of Control” columns are industrially oriented sum-maries of innovations in control technology. “Focus on Education” typically describes some aspect of education such as novel control experiments. “Lecture Notes” can be theoretical in nature as long as they have clear tutorial value and intent. See recent issues for examples of these and other types of columns. Authors are encouraged to contact the editor-in-chief about the suitability of potential columns.

A detailed Author’s Guide, a sample formatted manuscript, and LATEX template can be found at http://www.ieeecss.org/publica-tions/csm/submissions. The specifications in this Guide should be followed by all submissions.

All manuscripts should be submitted electronically to the IEEE Control Systems Magazine Web site, https://css.paperplaza.net/conferences/scripts/start.pl, with inquiries on appropriateness of content emailed to [email protected] ISSUES: IEEE Control Systems Magazine encourages proposals for special issues. Proposers are encouraged to contact the editor-in-chief to discuss potential topics.BOOKS AND CONFERENCES: Submit information about recently published books to the associate editor for book reviews. Sub-mit information about past and future conferences to the corresponding editor for conferences. ADVERTISING: IEEE Control Systems Magazine accepts advertising for educational products, books, software, conferences, employment, and control-related technology. For information about advertising, contact Susan Schneiderman, Business De-velopment Manager, IEEE Magazines, 445 Hoes Lane, Piscataway, NJ 08854 USA; +1 732 562 3946; fax: +1 732 981 1855; [email protected] CONTROL SYSTEMS MAGAZINE—(ISSN 1066-033X) (ISMAD7) is published bimonthly by The Institute of Electrical and Elec-tronics Engineers, Inc. Headquarters: 3 Park Avenue, 17th Floor, New York, NY 10016-5997, U.S.A. +1 212 419 7900. Responsibility for the contents rests upon the authors and not upon the IEEE, the Society, or its members. The magazine is a membership benefit of the IEEE Control Systems Society, and subscriptions are US$4.00 per member per year (included in Society fee). Replacement cop-ies for members are available for US$20 (one copy only). Nonmembers can purchase individual copies for US$92.00. Nonmember subscription prices are available on request. Copyright and Reprint Permissions: Abstracting is permitted with credit to the source. Libraries are permitted to photocopy beyond the limits of the U.S. Copyright law for private use of patrons: 1) those post-1977 articles that carry a code at the bottom of the first page, provided the per-copy fee indicated in the code is paid through the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01970, U.S.A.; and 2) pre-1978 articles without fee. For other copying, reprint, or republication permission, write to: Copyrights and Permissions Department, IEEE Service Center, 445 Hoes Lane, Piscataway NJ 08854, U.S.A. Copyright © 2014 by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Periodicals postage paid at New York, NY and at additional mailing offices. Postmaster: Send address changes to IEEE Control Systems Magazine, IEEE, 445 Hoes Lane, Piscataway, NJ 08854 U.S.A. Canadian GST #125634188 Printed in U.S.A

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AUGUST 2014 « IEEE CONTROL SYSTEMS MAGAZINE 37

P E O P L E I N C O N T R O L «

Four IEEE Fellows doing research in control are interviewed in this column.Jorge Cortés is an associate professor at the University

of California, San Diego (UCSD). He received a Licenciatura degree in mathematics from Universidad de Zaragoza, Spain, in 1997 and a Ph.D. in engineering mathematics from the Uni-versidad Carlos III de Madrid, Spain, in 2001. He was a post-doctoral research associate at the University of Twente, The Netherlands, and the University of Illinois at Urbana-Cham-paign before joining the faculty at the University of Califor-nia, Santa Cruz, in 2004. He moved to UCSD in 2007. He has served or currently serves as an associate editor for many jour-nals, including IEEE Transactions on Automatic Control, SIAM Journal on Control and Optimization, and Systems & Control Letters. He is the author of more than 150 journal and proceed-ings papers and of the book Geometric, Control and Numerical Aspects of Nonholonomic Systems (Springer-Verlag, 2002) and coauthor of the book Distributed Control of Robotic Networks (Princeton University Press, 2009). His research interests are in multiagent systems, distributed optimization, and networked games with applications to robotics, adaptive sampling, and cyberphysical systems.

Ali Jadbabaie is the Alfred Fitler Moore Professor of Net-work Science at the University of Pennsylvania (Penn), cur-rently on sabbatical as a visiting scientist at the Laboratory for Information and Decision Systems at the Massachusetts Institute of Technology. He received a B.S. with high honors from Sharif University of Technology, Tehran, Iran, in February 1995, an M.S. in electrical and computer engineering from the University of New Mexico in Albuquerque in December 1998, and a Ph.D. in control and dynamical systems from the Cali-fornia Institute of Technology (Caltech) in December 2000. He was a postdoctoral scholar at Caltech and Yale before joining the faculty at Penn in July 2002. At Penn, he has secondary appointments in the Departments of Computer and Information Science and Operations and Information Management in the Wharton School. He is a faculty member of the General Robot-ics, Automation, Sensing, and Perception (GRASP) laboratory

and is the cofounder and director of the Raj and Neera Singh Program in Networked and Social Systems at Penn, which is a new undergraduate interdisciplinary degree program focused on network science and engineering, operations research, and computational social science. He is the inaugural editor-in-chief of IEEE Transactions on Network Science and Engineer-ing, a new interdisciplinary IEEE transactions cosponsored by IEEE Computer, Communications, and Circuits and Systems Societies, that launched in 2014. He has served as an associ-ate editor of IEEE Transactions on Control of Network Systems and the Informs Journal Operations Research. His research interests are in multiagent coordination and control, distributed optimization, network science, network economics, and collec-tive robotics.

William “Mac” M. McEneaney is a professor at UCSD. He received his B.S. and M.S. degrees in mathematics from Rens-selaer Polytechnic Institute in 1979 and 1983, respectively, and the M.S. and Ph.D. degrees in applied mathematics from Brown University in 1990 and 1993, respectively. He was an analyst at PAR Technology from 1980 to 1982 and an analyst at the Jet Propulsion Laboratory from 1984 to 1989. Since receiving his Ph.D., he has been at Carnegie Mellon University, North Caro-lina State University, and, currently, at UCSD. He also acted as a program manager in dynamics and controls at AFOSR during 2008–2009. He has served as an associate editor of several journals including IEEE Transactions on Automatic Control, Systems & Control Letters, and SIAM Journal of Control and Optimization. He has consulted with many defense contractors, including Lockheed-Martin, Draper Laboratories, United Tech-nologies, Northrop-Grumman, and Tempest Technologies. He has edited two books, Stochastic Analysis, Control, Optimiza-tion and Applications (with George Yin and Qing Zhang) and Adversarial Reasoning: Computational Approaches to Reading the Opponent’s Mind (with Alexander Kott) and is the author of Max-Plus Methods for Nonlinear Control and Estimation (Birkhäuser, Basel, 2006). He has also authored/coauthored more than 75 journal and proceedings papers. His current research interests are in nonlinear control and game theory and their application to defense, space, and quantum systems.

Anna G. Stefanopoulou is a professor of mechanical engi-neering and naval architecture and marine engineering at

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the University of Michigan and the director of the Automotive Research Center, which is a U.S. Army Center of Excellence in Modeling and Simulation of Ground Vehicles. She earned her diploma in naval architecture and marine engineering in 1991 from the National Technical University of Athens, Greece, and her Ph.D. in electrical engineering and computer science in 1996 from the University of Michigan. She was a technical specialist at Ford Motor Company in 1996–1997 and an assis-tant professor at the University of California, Santa Barbara, in 1998–2000. She is the inaugural chair of the ASME Dynamic Systems and Control Division (DSCD) Energy Systems Tech-nical Committee, a member of the SAE Dynamic System Mod-eling Standards Committee, and a member of a U.S. National Academies Committee on Vehicle Fuel Economy Standards.

She has served as an associate editor of ASME Journal of Dynamic Systems Control and Measurements, IEEE Trans-actions in Control Systems Technology, and International Journal of Vehicle Autonomous Systems. She served as the vice-chair for Industry and Applications for the 2008 Ameri-can Control Conference and as vice-chair and chair of the Transportation Panel of the ASME DSCD in 1997–1999 and 1999–2002, respectively. She has coauthored a book, Control of Fuel Cell Power Systems: Principles, Modeling, Analysis, and Feedback Design (Springer Verlag, London, 2004), ten U.S. patents, five best paper awards, and 200 publications on the estimation and control of internal combustion engines and electrochemical systems such as fuel cells, batteries, and capacitors.

JORGE CORTÉSQ. How did your education and early career lead to your initial and con-tinuing interest in the control field?

Jorge: That is an interesting ques-tion, because I am sort of a latecomer to the control field. I have always had an inclination for mathematics. My father being an engineer probably also helped shape an appreciation for taking an an-alytical perspective on practical prob-lems. My undergraduate degree was in mathematics. During my senior year, I had the opportunity to do some under-graduate research with Prof. Manuel de León and Prof. David Martín de Diego at the High Council of Scien-tific Research in Spain, who combined differential geometry and analyti-cal mechanics to study the dynamics of a variety of physical systems. This opened a more applied perspective on

the use of mathematics for me, and I ended up doing my Ph.D. in engineer-ing mathematics.

The topic of my Ph.D. thesis was mechanical systems subject to non-holonomic constraints, which are a rich family of systems with a lot of structure that naturally lend themselves to basic control questions such as controllabil-ity, motion planning, optimal control, and stabilization. This eventually got me in touch with all the exciting activ-ity on geometric mechanics and con-trol that was taking place at the time at the California Institute of Technol-ogy (Caltech), work done either physi-cally there or connected in one way or another to Caltech.

I was hooked by the elegant ap-proach to address such fundamental questions, and I wanted to be part of this activity, so I took advantage of funds for

research stays abroad pro-vided by the fellowship I had from the Spanish gov-ernment to visit Prof. Jim Ostrowski at the GRASP Laboratory at the Univer-sity of Pennsylvania in 2000 and Prof. Francesco Bullo at the Coordinated Sciences Laboratory at the University of Illinois at Urbana-Cham-paign (UIUC) in 2001. Both of them were super fun vis-its that opened my eyes to the control field, and by the

time I finished my Ph.D., I was a new convert. I was fortunate enough to get the opportunity to work as a postdoc with Arjan van der Schaft at the Uni-versity of Twente on gradient realiza-tions of nonlinear control systems. My second postdoc was back in the United States with Francesco at UIUC, right at the time when the field of cooperative control of multiagent systems was tak-ing off, and that put me on the path that I am currently on.

Q. What are some of your research interests?

Jorge: My current research inter-ests revolve around different aspects of networked multiagent systems, focused on algorithm design and analysis motivated by concrete appli-cations. I am interested in distrib-uted optimization problems, where the decisions of individual agents are coupled through their objective func-tions, the constraints on the network, or both. In such scenarios, agents must collaborate with each other to attain a global optimum. I look for prov-ably correct distributed dynamics that scale gracefully with the number of agents and are robust to disturbances, changes in the network, and such. I am focusing on power networks, although this class of problems finds applica-tions in numerous domains.

A more strategic take on this natu-rally leads to another area of interest

Jorge Cortés with his family in their home’s backyard in San Diego, California.


to my group right now, which is networked games. These are games that involve either networked enti-ties as players, forces that operate over networks, or both, and where information is distributed across multiple layers and only partially available to individual players. I find quite fascinating how the interaction between cooperation and competition shapes the behav-ior in these strategic scenarios. Another area of recent interest is real-time implementation of con-trollers in distributed setups and, in particular, self- and event-trig-gered control of cyberphysical sys-tems. The main thrust is to under-stand to what degree agents can be opportunistic in the transmission and acquisition of information with two goals in mind.

One goal is to preserve guar-antees on task completion and robust-ness of the networked controllers, and the other goal is to make sure that the resulting implementation efficiently uses the sensing, communication, actu-ator, and computing resources available to the network. I have found the combi-nation of these aspects and the distrib-uted nature of networked multiagent systems to be a fertile area that brings up numerous issues of interest such as autonomy, robustness to uncertainty, and tradeoffs in implementation.

I am also excited about an ongo-ing NSF-funded collaborative project with the Scripps Institute of Oceanog-raphy, where we look at the estimation of ocean flow fields and, in particular, internal waves. These waves are impor-tant in oceanography because, as they travel, they are capable of displacing small animals, such as plankton, larvae, and fish. We use a group of buoyancy-controlled drogues that can change their depth in the water column and “be displaced” the same way that small animals are. While underwater, indi-vidual drogues do not have access to absolute position information and rely only on inter-drogue measurements to estimate the parameters that define the internal wave. These scenarios

have been a source of really interesting control problems. Finally, I maintain ongoing research collaborations on geometric mechanics and control with researchers in Spain going back to the time of my Ph.D.

Q. What courses do you teach relat-ing to control? Do you have a favor-ite course? How would you describe your teaching style?

Jorge: Most of the courses related to control that I have taught are at the graduate level: Nonlinear Systems, Nonlinear Control, Hybrid Systems, Cooperative Control of Multiagent Sys-tems, and next year, I hope to be able to teach Game Theory for Engineers. It is really difficult to select a favorite. I love the basics of systems and dynamics, and I always seem to learn or realize a new thing every time I teach Nonlinear Systems or Nonlinear Control. I have developed the other courses I teach at some point in time based on my research interests, and they are indeed close to my heart, as each one is con-nected with a specific time frame and some paper, set of papers, or book.

The question about the teaching style is interesting. I guess I aim to present things in a way that is as simple and clear

as possible (don’t we all?). I don’t shy away from difficult concepts, but I always attempt (students should tell you if I succeed!) to give the students something they can hang on to get through the abstractions. Another thing I always try to keep in mind is the fact that students are new to the concepts, and I try to take the per-spective of how it felt when I was first introduced to them, and what the difficulties in grasping them where, so that I can better frame the exposi-tion. Finally, I try to make the class engaging, with as many questions from students as possible, because it keeps the class’s attention up, allows me to calibrate where exactly they are in terms of understanding, and it is more fun. Depending on the course, I like to ask them to do a final project that somehow combines the main take-away messages from the

course to make sure they know how to use what they have learned.

Q. What are some of the most prom-ising opportunities you see in the control field?

Jorge: I should start by stating the obvious: my opinion is biased by my own research interests and the areas where I believe that we, as a society, face greater challenges in the future. In terms of areas, I think there are many where control should play an impor-tant role. Energy is the first area that comes to mind, with a great variety of control-related problems in applica-tions such as the smart grid, power networks, renewables, and smart build-ings. The environment and the sustain-able use of the limited resources of the planet is another important area where I believe control could contribute, par-ticularly to things such as water irriga-tion, precision farming, and ecosystem management. Another area where I also see an increased role for control is transportation systems. The increasing availability of real-time information to all actors involved (consumers, authori-ties) enables many possibilities, includ-ing more efficient choices, better trans-portation options, and more intelligent

Jorge during a trip to Sequoia National Park.


Profile of Jorge CortésCurrent position: associate professor, University of California, San Diego.Visiting and research positions: University of California, Santa Cruz.Contact information: University of California, San Diego, Mailstop 0411, 9500 Gilman Drive, La Jolla, California 92093 USA, +1 858 822 7930, [email protected], http://tintoretto.ucsd.edu/jorge.IEEE Control Systems Society experience highlights: associate editor, Con-ference Editorial Board, 2005–2009; chair, Technical Committee on Manu-facturing Automation and Robotic Control, 2009–2012; associate editor, IEEE Transactions on Automatic Control, 2009–2012; associate editor, IEEE Con-trol Systems Magazine, 2012–present.Notable awards: Young Researcher Prize, Spanish Society of Applied Math-ematics, 2006; IEEE Control Systems Magazine Outstanding Paper Award, 2008; SIAM Review SIGEST selection from the SIAM Journal on Control and Optimization, 2009; IEEE Control Systems Society Distinguished Lecturer, 2010–present; O. Hugo Schuck Best Paper Award, American Automatic Con-trol Council, 2012; IEEE Fellow, 2014.

infrastructure. The list could go beyond these areas to include social networks, biology, advanced manufacturing, smart medical devices, healthcare, and many others.

A theme that strikes me as common across many of these areas is the obser-vation that, as access to large amounts of information becomes more perva-sive, the interconnection and interac-tion between agents (understood in a broad sense, such as individuals, clus-ters of individuals, or modes) becomes increasingly significant, unpredictable, and complex. I think systems and con-trol theory can have a significant impact in network science, and specifically in guaranteeing the reliable and safe operation of networked systems across multiple disciplines where autonomy and decisions at the individual level affect the overall system behavior and its performance.

Q. You are the author of two books in the control field. What topics do these books cover?

Jorge: The first book I wrote is Geo-metric, Control, and Numerical Aspects of Nonholonomic Systems, and it is a spin-off of my Ph.D. thesis. The book presents a differential geometric approach to the study of the dynamics of mechanical systems subject to nonholonomic con-straints. The term nonholonomic refers to the fact that the constraints cannot be expressed in terms only of the con-figuration variables of the system but

instead truly require configuration and velocities. Nonholonomic systems are present in multiple domains, including robotics, locomotion, and multibody dynamics. What motivated me to write the book is the conviction that a better understanding of the geometric struc-tures of mechanical systems helps both analysis and design to solve standing problems and identify new challenges.

The book starts from the derivation of the equations of motion via the clas-sical Lagrange-d’Alembert principle and builds on tools from differential geometry to develop intrinsic, coordi-nate-free formulations of them. This sets the stage for the study of a variety

of classical topics in mechanics; such as symmetry, reduction, and reconstruc-tion of the dynamics, and integrabil-ity and control, such as controllability, series expansions, and motion plan-ning. The “geometric emphasis” pays off in many of the results presented in the book, but perhaps this is more apparent in the new class of numerical integration schemes proposed in the manuscript. The book illustrates how the geometric perspective adopted in the design of these integrators explains their provable superior performance with respect to standard numerical methods for nonholonomic systems. These schemes are called nonholonomic integrators and have sparked what today is an area of active research in geometric mechanics.

The second book is Distributed Control of Robotic Networks, which was cowritten with Prof. Francesco Bullo now at UC, Santa Barbara, and Prof. Sonia Martínez at UCSD. The book is the culmination of a fruitful and prolific collaboration over the years. (I can still remember the fun we had together while writing the book and our endless joint working sessions at coffee shops of Santa Cruz, Santa Barbara, and San Diego.) The book is a self-contained introduction to the coop-erative control of networked systems with a distinctive blend of computer

Jorge and his research group, with UCSD’s Geisel Library in the background.


ALI JADBABAIEQ. How did your education and early career lead to your ini-tial and continuing interest in the control field?

Ali: My choice of control systems as a major happened some-what through serendip-ity. I entered college in 1990. At the time, elec-trical engineering was the hottest engineering discipline in Iran and was divided into four branches: elec-tronics, communications, control, and power systems. The top 20–30 students (out of roughly 250,000) in the National Entrance mostly selected electronics at Sharif University. Following the herd mentality, I did the same. For my second choice, I chose control systems because I had heard it was more “math based” and I liked math. I ranked 45 in the exam, so I did not make it to my first choice.


Ali: My interests are broadly on the interplay of network dynamics and opti-

mization, in a variety of contexts. Early on in my career, I worked on coordination

and control of multiro-bot formations. Later I became interested in net-works, learning, opinion dynamics, and applica-tions to social and eco-nomic systems.

Q. What courses do you teach relating to control?

Ali: I have been mostly teaching opti-

mization courses over the last six years. In the fall semester, I teach a course on

linear programming, duality, integer programming, and network flows. In the spring, I teach a course on con-vex optimization theory, applications, and algorithms. I have also taught special topics courses on networked dynamic systems.


Ali: I think ideas from decision the-ory and control, interpreted broadly, have an important role to play in many applications ranging from robotics to data science, network science, and economics, as well as synthetic and

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science, control theory, and robotics. The first two chapters cover fairly gen-eral concepts and techniques currently used for distributed and multiagent sys-tems, such as graph theory, distributed algorithms, matrix theory, and geomet-ric notions. The book also puts forth a model for robotic networks, including complexity measures, to help rigorously formalize coordination algorithms run-ning on them. The remaining chapters present cooperative strategies to achieve a variety of coordination tasks, such as connectivity maintenance, rendez-vous, deployment, and estimation. The book is freely available online—from its inception, we were sure about this

choice to maximize its accessibility and impact —and based on the feedback we have received from the community, I am very glad that we made this choice.

I would really like to write a third book, on discontinuous dynamics and nonsmooth systems. I have not found the time yet but I hope I will; a few years ago I wrote a tutorial on the topic for IEEE Control Systems Maga-zine that many people have found use-ful, so that would be for sure my start-ing point.

Q. What are some of your interests and activities outside of your profes-sional career?

Jorge: I like reading modern litera-ture; watching good-quality TV series on Netflix; playing and watching soc-cer; running, hiking, exercising in gen-eral; and swimming in the hot days of summer. Over the last few years, I have not practiced these activities as much as I used to because of the arrival of my son (four years old) and daughter (one year old). My wife and I love spending time with them, and I would say they are our main activity, professional or otherwise!

Q. Thank you for your comments.Jorge: Thank you for the invitation

and the opportunity to reach the IEEE Control Systems Magazine readership.

Ali Jadbabaie.

Ali in his office.


systems biology. However, this poten-tial can only materialize if ideas from decision and control are connected to domain-specific expertise.


Ali: My major extracurricular activity is playing classical guitar. I even have a YouTube channel that you can check out. Also, I am an avid fan of politics and movies.

Q. Thank you for your comments.Ali: My pleasure, thank you!

WILLIAM “MAC” M. McENEANEYQ. How did your education and early career lead to your initial and con-tinuing interest in the control field?

Mac: As an undergraduate at Rensselaer, I had no concept of con-trol theory. Then, at my first pro-fessional position after my B.S., I encountered the concept of optimal estimation, particularly in relation to tracking and defense applica-tions. When I returned to Rensselaer for graduate work, I took an interest in functional analysis. This led to a special topics course with Andrzej Manitius on optimization, mainly oriented toward the Pontryagin max-imum principle, and that is perhaps where I first came into contact with academic-grade research in control theory. I left Rensselaer after my mas-ter’s, taking a position in the warm climate of southern California at the Jet Propulsion Laboratory. There, I was able to apply my understanding of control and estimation in a variety of space applications, including civil-ian air traffic monitoring, the space defense initiative, and aeromaneu-vering guidance for Mars missions.

Although the applications were inter-esting, I developed a longing to make a more fundamental contribution. I returned, again, to graduate school, this time to Brown, with a specific intent to work in the general area of control theory, including stochastic processes and math/finance. Work-ing with Wendell Fleming, I became deeply involved in nonlinear sto-chastic control and games, and I have never regretted the turn to funda-mental research.


Mac: My current interests are in sev-eral areas, with perhaps the most well known being the application of max-plus algebra to the solution of problems in optimal control and estimation, with the surprising result that the dynamic pro-gramming operator is max-plus linear, even in the case of nonlinear systems. Other recent interests have included game theory, quantum control, and fundamen-tal solutions for Riccati equations and two-point,

boundary-value problems in conserva-tive systems.

Q. What courses do you teach relating to control? How would you describe your teaching style?

Mac: I enjoy teaching both Optimal Control and Analysis. As a teacher, I try to give the students a sense of the abstract beauty to be found in sub-jects, while at the same time adding some sense of how advances in the theory have lead to the breakthroughs in applications that the community has made over the recent decades.


Profile of Ali JadbabaieCurrent position: Alfred Fitler Moore Professor of Network Science, University of Pennsylvania. Visiting and research positions: currently at the Laboratory for Information and Decision Systems, Massachusetts Institute of Technology, as a visiting scientist.Contact information: University of Pennsylvania, Department of Electrical and Systems Engineering, Levine 372, 3330 Walnut Street, Philadelphia, Pennsylva-nia 19104 USA, http://www.seas.upenn.edu/~jadbabai.IEEE Control Systems Society experience highlights: member of the Conference Editorial Board for many American Control Conferences and IEEE Conferences on Decision and Control (CDC); associate editor, IEEE Transactions on Control of Network Systems; semiplenary speaker, CDC 2009.Notable awards: NSF Career Award; ONR Young Investigator Award; O. Hugo Schuck Best Paper Award, American Automatic Control Council; George S. Axelby Best Paper Award, IEEE Control Systems Society; IEEE Fellow.

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Date of publication: 14 July 2014 Mac enjoying lunch during a meeting in Italy.


Mac: The field is at another cross-roads. In recent years, there has been somewhat of a boost from new appli-cation areas, the one I am most aware being that of the new opportunities en-gendered by networked, autonomous, and semiautonomous system applica-tions, such as applications regarding the coordinated use of unmanned aerial vehicles. In some large-scale ap-plications, we are now competing with alternative approaches, such as out-growths of expert systems and so on. In addition to the stimulation of com-petition, this is also causing us to re-think some of the fundamental issues regarding our point of view, which is certainly a good thing.

At the same time, in spite of the huge theoretical advances of earlier decades, where the maximum princi-ple and dynamic programming were first conceived, we have failed to cap-italize on those advances because the computational requirements were (and remain) well beyond our capa-bilities. Some new application areas, such as quantum systems, where the state dimension is extremely high, highlight this difficulty. In fact, one could argue that entire subdis-ciplines have since arisen as means of circumventing the computational infeasibility of the early theory. The challenge of computation remains one of the biggest obstacles that we have yet to overcome.

Q. You are the editor and author of books in the control field. What is the topic of the books that you authored?

Mac: Although I have edited a couple of volumes, the only proper book I have written regards application of the max-plus algebra to the solution of problems in nonlinear control and estimation. The max-plus algebra is truly the way to view optimal control, and dynamic programming in particular. The reason is that, even for nonlinear control and estimation problems, the dynamic pro-gramming operator is max-plus linear.

This opens up a tremendous set of lin-ear systems tools for application in non-linear problems—with the caveat that it is required to think in terms of max-plus addition and multiplication instead of our traditional operations.


Mac: I live for control.

Q. Thank you for your comments.Mac: Thank you for taking the

time to do this.

Mac with Prof. Hidehiro Kaise while visiting Nagoya University.

Mac outside a pie shop while visiting the University of Melbourne.

Profile of William M. McEneaneyCurrent position: professor, University of California, San Diego.Visiting and research positions: PAR Technology, Jet Propulsion Laboratory, Carnegie Mellon University, North Carolina State University, AFOSR.Contact information: Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093 USA, +1 858 822 5835, [email protected], http://maeresearch.ucsd.edu/mceneaney/. Notable awards: IEEE Fellow, 2014.

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