Tom Schriber (left) and Robert Sargent

Robert G. Sargent, Professor Emeritus of Electrical Engineering and Computer Science at Syracuse University, received the 2002 Lifetime Professional Achievement Award from the Institute for Operations Research and the Management Sciences-College on Simulation (INFORMS-CS). The award was presented to Dr. Sargent at the Opening Session of the 2002 Winter Simulation Conference, which was held in San Diego, California, on December 9, 2002.

The Lifetime Professional Achievement Award is the highest honor given by INFORMS-CS, and it is given at most once a year. The award recognizes major contributions to the field of simulation that are sustained over most of a professional career, with the critical consideration being the total impact of those contributions on the field. An individual's contributions may fall in one or more of the following areas:

1. contributions to research,
2. contributions to practice,
3. dissemination of knowledge,
4. development of software or hardware,
5. service to the profession, and
6. advancement of the status or visibility of the field.

Bob Sargent first became involved with discrete-event simulation in the early 1960s as a graduate student at The University of Michigan, where he studied simulation methodology and developed simulation models. After completing his Ph.D. at Michigan in 1966, Bob joined the faculty at Syracuse University and taught simulation there until he retired in the late 1990s. Bob contributed significantly in several areas of simulation during his professional career. He made important research contributions to simulation methodology, many having a practical flavor. His sustained service to the simulation profession is well known and has been formally recognized with several service awards. He disseminated information about simulation and advanced its visibility through numerous presentations and tutorials at major international conferences and through his work with the U.S. Air Force. Bob was also one of the first individuals to initiate the modeling of computer systems for performance evaluation. His most significant professional achievements in simulation are detailed below.

1. Contributions to Research
Bob has made major research contributions in several areas of simulation methodology.

• In the modeling area, he coauthored the definitive paper on hybrid analytic/simulation modeling. He made important contributions subsequent to the original development of Event Graph Models, which are graphical representations of the event world view. Bob led the development of Control Flow Graph Models, which are graphical representations of the process world view. He and one of his students later extended these graphical representations by evolving Hierarchical Control Flow Graph Models to facilitate development, maintenance, execution, and reuse of complex simulation models. Bob and another of his students updated and extended the experimental frame concept.
• In the area of computational speedup of simulation model execution, he and his students made contributions to event-list processing, the use of associative processors (associative processing), and the use of parallel computers (parallel simulation).
• In the output analysis area, Bob's contributions include the following: development of new statistical estimators; a comprehensive theoretical and experimental comparison of confidence interval estimators; creation of a methodology for fitting and validating metamodels that use different types of basis functions; and the development of the cyclic regenerative method.
• In the verification and validation (V&V) area, he raised the visibility and understanding of the roles of verification and validation and the distinction between them. He developed a graphical view of how V&V relates to the modeling process, which is known as the "simplified view of the modeling process," and which has become widely used. He and a student developed a statistical framework within which to view validation. He also developed numerous validation techniques, approaches, and methodologies.
• In the area of the theory of simulation, he and a student developed a general framework for discrete-event modeling and simulation based on formal logic.

2. Contributions to Practice
Bob was involved with some of the first data collection, data analysis, and modeling of computer systems for performance evaluation. Some of this work is contained in his publications. Much of Bob's research work was directed toward obtaining results that can be used by practitioners. Furthermore, he worked with the U.S. Air Force on military problems, as well as serving on some Department of Defense committees.

3. Dissemination of Knowledge
Bob has been an active disseminator of simulation knowledge to practitioners and researchers alike. He started giving tutorials on "Introduction to Simulation Languages" and "Output Analysis" in the 1970s and later gave tutorials on "Verification and Validation." These presentations were made at Winter Simulation Conferences (WSCs); Symposia on the Simulation of Computer Systems; NATO meetings; joint international conferences of The Institute of Management Sciences (TIMS) and the Operations Research Society of America (ORSA) [now merged to form the Institute for Operations Research and the Management Sciences (INFORMS)]; meetings of local professional societies; and seminars at universities. Bob also disseminated state-of-the-art knowledge on simulation through numerous presentations at conferences and universities around the world. He was a coeditor of the 1976 and 1977 Proceedings of the Winter Simulation Conference; coeditor of a special issue of Operations Research on simulation, (1983, Vol. 31, No. 6); and coauthor of state-of-the-art bibliographies. He was a National Lecturer with the Association for Computing Machinery (ACM) during the period 1985-1989, giving numerous talks on simulation at ACM chapters. In addition, he taught simulation credit-courses at Syracuse University for over thirty years; and he chaired the dissertations of nine Ph.D. students, six of whom did their Ph.D. work in the area of simulation.

4. Development of Software Bob and his students developed prototype simulation systems, including the Hierarchical Modeling and Simulation System-Java (HiMASS-j), to demonstrate the concept and workability of using the paradigm of the Hierarchical Control Flow Graph Model together with visual interactive simulation model building and an updated approach to experimental frames. Some of these developments were done on behalf of the U.S. Air Force.

5. Service to the Profession
Bob made many significant service contributions to the simulation community in a variety of areas. Bob was and still is very active in TIMS/College on Simulation and Gaming, now known as INFORMS-College on Simulation. He held all the offices in the College, including the position of president (1978-1980). He served on most of the College's committees, and was involved in establishing all the awards given by the College.

Bob's contributions in service to WSC over the past four decades deserve special mention. He was the representative of the Institute of Industrial Engineers (IIE) to the conference committee of each annual WSC from 1974 to 1984. Bob was instrumental in initiating the rebirth of WSC in 1976, serving as the Associate Program Chair for the 1976 WSC, and then as the General Chair for the 1977 WSC. He played a key role in the establishment of the WSC Board of Directors; and he drafted a set of bylaws for the WSC Board, coordinating three revisions of that document that culminated in final Board of approval of its by-laws in 1979. Bob also formulated the duties of the various officers of the Board. He continued as the IIE representative to the Board from 1976 to 1984, and he served as Board Chair from 1979 to 1981. Bob has also served various annual WSCs as a track coordinator and session organizer.

Bob's editorial work is commensurate with the other dimensions of his service to the simulation community. He helped establish the Simulation Department of Management Science in the mid-1970s; and then he played a critical role in saving that department from closure on three separate occasions in the late 1970s and the early 1980s. He was the Departmental Editor for Simulation Modeling and Statistical Computing (Research Contributions) of the Communications of the ACM, serving from 1980 to 1985. Bob was involved in establishing the ACM Transactions on Modeling and Computer Simulation (TOMACS); and he served on the TOMACS Editorial Advisory Board from 1989 to 1997. Over the years, he served as a referee for numerous archival journals in the fields of industrial engineering, operations research, and computer science. For the special fiftieth anniversary issue of Operations Research (2002, Vol. 50, No. 1), Bob coauthored an invited article on the past, present, and future of the field of simulation that was titled "Perspectives on the Evolution of Simulation."

Bob service to the simulation community has spanned numerous professional societies and major international conferences. Bob gave the Keynote Address at the 1998 Conference on Simulation and Visualization (in Magdeburg, Germany); and he gave the Doctoral Colloquium Keynote Address at the 2000 WSC. He was a Director-at-Large of the Society for Computer Simulation (now the Society for Modeling and Simulation International, or SCS) from 1984 to 1987; he was a member of the Executive Committee for Simulation of the Institute of Electrical and Electronics Engineers (IEEE) Computer Society for several years; and he was an active member of the ACM Special Interest Group on Simulation (SIGSIM), serving on committees and performing various tasks. Bob organized numerous sessions on simulation at various national and international meetings. Bob has also provided service to the National Science Foundation, much of which had to do with the field of simulation. In addition, he served various professional societies in areas other than simulation. For his service work, Bob received awards from the following organizations: ACM; IIE; the WSC Board of Directors; and the INFORMS-College on Simulation (in particular, he received the College's Distinguished Service Award in 1988).

6. Advancement of the Visibility of Simulation
Over the past four decades, Bob has increased the visibility of simulation through his numerous presentations at a broad range of professional meetings-in particular, the national and international conferences of ACM, IEEE, IIE, INFORMS, and SCS-and in his work with the U.S. Air Force, where he promoted simulation as a problem solving technique.

7. Summary
The nomination of Bob Sargent for the INFORMS-CS Lifetime Professional Achievement Award was accompanied by letters of endorsement from ten distinguished individuals who can evaluate authoritatively various facets of Bob's remarkable career. A common theme running through the ten letters of endorsement is that in all his professional activities, Bob has set a standard for uncompromising integrity and a commitment to excellence that many people in the international simulation community have tried to emulate. Perhaps Lee Schruben expressed this sentiment most forcefully in his letter of endorsement:

At critical points in my career and life, he has been the most supportive voice. Above all else, Bob is always the teacher. He is direct but constructive in his criticisms, and with high but attainable standards. Even after losing an argument with Bob, he somehow makes me feel better than before the exchange. In academics, where arrogance and negativity often mask themselves as a commitment to high standards, Bob stands out as positive, able to see and add value. He tries to look for what is right as well as what may be wrong with any new idea. There are several lines of research that I would have abandoned without Bob's encouragement and some that I did abandon, or should have, for lack of it.

If it is possible for someone to be everyone's friend, then Bob has done it by being a best friend to our profession. I am happy to count him among mine. Bob's accomplishments stem from one core value: he cares, and by doing so makes us all care.

Lifetime Professional Achievement Award Winners