The INFORMS simulation section became the INFORMS Simulation Society in November 2004. While we are the newest 'Society' in INFORMS, the section was started as the College on Simulation and Gaming in The Institute for Management Science (TIMS) in 1963, long before the ORSA/TIMS merger to form INFORMS in 1995. The Societies page on the INFORMS web site describes our mission in brief:
"The INFORMS Simulation Society provides a focus within INFORMS for the field of simulation; encourages the development and dissemination of knowledge in simulation and related fields; recognizes outstanding contributions both in technical innovation and in service to the profession; promotes communication and interaction among individuals and organizations who share an interest in simulation, including the sponsoring of conferences on simulation and sessions at INFORMS meetings; encourages students to study topics in simulation and to pursue related professional careers; and supports the continuing education of all simulation professionals."

There are about 500 members of the Society, including students, academics, and people employed in industry, government and the military. Our members are from all over the world. Our current Vice-President resides in France and our Newsletter Editor in Singapore! Before describing the activities of the Society, it helps to understand a bit about the special meaning of simulation for our group.

What is Simulation?
Fundamentally, simulation is the imitation of a real process or system. The emphasis in our society has some additional characteristics. Almost always, the following characteristics apply: i) the imitation is produced using a computer program, ii) the simulation is dynamic, modeling changes in the system or process over time, and iii) the simulation is stochastic, having randomly varying performance. Dynamic changes may be continuous (such as a temperature or position) or discrete (such as a customer arrival or a machine breakdown). Our Society's primary focus has been on simulations whose changes are discrete, either entirely or in part. A commonly used name for this type of simulation is Discrete-Event Dynamic Simulation (DEDS). Surprisingly, many systems with continuously varying characteristics are modeled using the DEDS approach. Examples include manufacturing lines, computer hardware, hospital services and call centers.

What is Simulation Used For?
Simulation is one of the most useful tool sets in the OR field. A number of surveys of OR practitioners show simulation as near the top (after statistics) in frequency of use. Simulation models reproduce some key behavioral aspects of the real system being modeled. For a hospital services simulation model, these might include the time patients wait before seeing a nurse, the amount of time the receptionist is busy, and the percent of time that examination and operating rooms are used. The key benefit of such simulations is to provide insight, in a number of ways: how the current system or process behaves, how behavior will be affected by changes in the environment (for example, average patient arrival rate) or changes in its design (for example, the number of nurses on duty), And how much variability one can expect. Simulation can also provide insight on expected behavior for a system not yet built. This last capability is useful for evaluating alternative designs for a system or process.

The insight provided by simulation leads to three key benefits. First, a better understanding of the system can lead to changes in the management and/or structure of the system that provide improved performance and reduced cost. Second, this understanding is achieved using experimentation with a low-cost computer model. Experimenting with the real system might be risky, costly or even impossible. Third, simulations generally run much faster than their real counterparts. Thus, once the simulation model is constructed, fast evaluation of design alternatives can speed the time to design and implement a new process, product or system.

Activities of the INFORMS Simulation Society
The INFORMS Simulation Society activities fall in several main categories: publications, conference organization and participation, sharing information with our membership, and sponsorship of awards.

While our Society has no journal of its own, our members play active roles as simulation area editors for the top journals in our field, including the INFORMS journals Operations Research, Management Science, the INFORMS Journal on Computing. In addition, our Society plays a key role for the annual publication, the Proceedings of the Winter Simulation Conference.

The Winter Simulation Conference (WSC) is the primary international conference for disseminating recent advances in the field of discrete-event and combined discrete- and continuous-simulation. The INFORMS Simulation Society is one of eight sponsors of this annual event. This conference attracts more than 500 simulation practitioners, researchers, and vendors, representing industry, government, the military and academia. The conference produces a refereed Proceedings. Recent Proceedings have had more than 200 papers and approximately 2,000 pages. They are available on-line at our Simulation Society web site, www.i-sims.org. The 2004 conference was held in Washington, D.C. and is described on the conference web site (www.wintersim.org). As part of the Winter Simulation Conference, our Society has sponsored (since 1988) a Ph.D. student colloquium on the Sunday of the conference. At the colloquium, doctoral students learn about career aspects and present their research. The colloquium is open to all conference attendees. The college provides a small honorarium for these students. We also support the attendance of women and underrepresented minorities (generally students).

Simulation is an important topic at other INFORMS conferences as well, especially the Fall INFORMS Conference, the Spring Practitioner Conference, and the INFORMS International Conference held in the Summer, jointly with other international organizations. Our Society sponsors simulation sessions at the Fall and Summer conferences. Information on these conferences is available at the INFORMS web site: www.informs.org/Conf/. Our Society's Vice-President (Stephen Chick, stephen.chick@insead.edu ) arranges the sponsored sessions.

The Simulation Society shares information with its members in a number of ways: through our email distribution list, our Fall and Spring Newsletters, and our web page. Our business meetings also provide information sharing and networking opportunities. These are held in the early evening at the Fall INFORMS meeting and the Winter Simulation Conference, and occasionally at other INFORMS conferences.

How are We Organized?
The INFORMS Simulation Society officers are President, Vice-president/President-Elect, Secretary and Treasurer, but there are many other volunteers who are involved in coordinating and facilitating the many activities of our Society. We have nine committees covering membership, communications, and awards, and an advisory council composed of the officers, past president, and four elected members. In addition, we have a Newsletter Editor and Associate Newsletter Editor who prepare the newsletters found on our web site. More than 30 people participate in one or more of these roles.

How Can You Participate?
Student members of INFORMS can join one section or society at no additional charge - just check the box on your membership application. If you are already a member of INFORMS and want to join our Society, the easiest way is to call the 1-800-4INFORM(s) number. There are significant benefits to joining a section, whatever it may be. Attending an INFORMS national conference can be daunting for a student, in terms of trying to meet people with similar interests, identifying high-quality talks, and making a circle of acquaintances and friends. Joining a section or society gives you an opportunity to connect with a smaller group with similar interests, to meet people who can become your future colleagues and mentors.

As a member of the INFORMS Simulation Society, you will be joining an especially friendly and active group. You will be notified of Society-sponsored sessions at major conferences. You will be invited to our business meetings, where you can help shape the activities of our Society and make new friends. These meetings typically have between 20-120 attendees, a much smaller group than the overall conference. You can volunteer to participate on one of our committees, and meet other students and professionals. You might get an idea for a presentation or a paper, or even organize a session of talks for an INFORMS meeting. We look forward to your participation!

For More Information
"Perspectives on the Evolution of Simulation," by Richard E Nance and Robert G Sargent. Operations Research. Jan/Feb 2002.Vol.50, pp. 161-174.

Winter Simulation Conference Web Site: www.wintersim.org