2019 Simulation Software Survey

The Apollo program and its historic first landing on the surface of the moon got a lot of attention in the news this year in commemoration of its 50th anniversary. We all applauded the achievement, and we can honor the drive and ingenuity that were required to achieve such a single goal. One glimpse of how computations were performed that guaranteed the travel to that distant target and safely back again was provided in the book (and movie) “Hidden Figures” [1]. Then, as now, a successful mission requires the ability to model – to simulate – the systems that are needed to bring the mission to its ultimate conclusion.

By coincidence, commercial simulation is also a half century old. In the interim since the last biennial survey of simulation products [2], the Winter Simulation Conference celebrated its 50th anniversary in 2017. That conference had its origins in the intellectual excitement and opportunities afforded by the earliest commercial simulation products (particularly GPSS), though it quickly grew to include any commercial simulation tool [3]. These tools held the promise to simplify the construction and running of models that had largely been hand-crafted programming efforts over the preceding decade.

Military Operations

The idea of modeling, simulating or gaming processes beset by uncertainty as a means of analysis is surely not a new idea. Consider, for example, the idea of reducing military operations to symbolic units whose movements were constrained by the mobility of the units, the type of terrain and logistical constraints while operating in the presences of enemy units. These war games had been a staple of staff colleges for more than a century. For the simulation to be useful, the representation of units and their operations had to at least mimic their actual performance. In short, one had to represent not merely the units and their positions but define the rules of their operation and their interaction with other units whether it was in combat or in movement over terrain.

As noted in Hill and Miller [4], the use of such gaming gained credence after the Franco-Prussian War because of its use by the German General Staff. Gaming of this type also was used by the United States Naval War College during the interwar period [5]. These studies are asserted to have had a large impact on the evolution of naval doctrine during WWII as operations evolved from battleship fleets to carrier battle groups, which came to dominate the war in the Pacific. A recent publication asserts that this evolution was largely fixed by 1933, laying the template for the fleet that did not come into being until near the end of the decade [5].

Of course, WWII gave rise to many new methods of analysis, including operations research and management science: the application of models and optimization to study and to improve both military and business processes. Simulation was among the tools developed during this time, given a boost, perhaps, from the Monte Carlo methods employed by the Manhattan Project to solve problems that were analytically intractable but capable of estimation using statistical sampling. All of these tools could be considered symbiotic with developments in computing machinery, for each required substantial computational power. All likewise benefitted from improvements in fundamental algorithms which permitted large-scale numerical operations that were accurate and reliable.

Yet for all of its versatility, simulation lagged behind the other tools in terms of respect. In one sense, this is a reflection that analytic models, where feasible, provide an exact solution, whereas simulation output is by its nature an uncertain, statistical estimate. In his survey of simulation, Robert Sargent [6] provides other reasons for this lesser status. One is the oft-printed advice that simulation was a brute force tool of last resort. This reflected the effort that was once required to build models. It may have also reflected the primitive nature and the limitations in analysis of those early days. And of course, until computational power increased, the number of replications and the size of simulation experiments would have been limited. Simulation analysis now has decades of development in theory and practice, and the range and versatility of the areas of application continues to grow.

Moreover, the last half century has also witnessed continual development in tools and in commercial products available to implement simulation. A plethora of simulation languages have been developed and refined and, in many cases, eventually superseded by newer and improved tools built on the old. This development echoes similar upwelling among programming languages and paradigms. As an aside, the OR/MS Today simulation surveys now cover a quarter century of reporting on available products, and are a source of information about the evolution of products within the field over that period.

The theoretical infrastructure of simulation has blossomed in parallel to this commercial development. There have been improvements in foundational components such as pseudo-random numbers, random variate generation, input modeling, output analysis and optimization. Since many of the simulation developers have academic roots or close ties to academics, these improvements have continually been incorporated into successive generations of commercial products.

Sophisticated Animations

Today we take for granted that simulation can generate increasingly sophisticated animations of the process being studied. This is one of the greatest assets of simulation, to convey visually the look and feel of the process being studied. This is not merely a matter of selling the model, though the ancient adage might be updated to observe that an animation might be worth thousands of statistics. Likewise, a good visualization is in effect a Turing test for the model: If it acts and looks like the real process, then the underlying model should be sound.

Animation also makes simulation suitable for training, gaming and entertainment. The latter is likely the greatest market for simulation and a driver for innovation in the realism and computational efficiency that makes increasingly realistic displays needed for virtual reality application. Simulation has long been used for training pilots and by the military. In both cases it is possible to include dangerous and complex scenarios that would be impossible or too costly to manage otherwise. After all, only one’s ego is hurt in a simulated crash, or in a simulated battle that is lost. Simulation in training is being extended to more mundane areas such as management and human resources, where one can practice giving a performance evaluation, for instance.

Not all objects that we wish to model in a simulation are passive elements, and these active elements may make their own decisions based on the context: Drivers on the road do not operate according to inflexible rules, and individual pedestrians may choose their own path based on the presence of other pedestrians. Agent-based simulation capabilities make it possible to include decision-making in simulated objects for models that can more faithfully model the behavior of autonomous entities.

In addition, a simulation is akin to a heavily instrumented test device; it is a generator of a vast number of measurements that may provide numerous measurements of location, utilization, temporary instances of congestion and many other statistics over time or location and as a function of multiple factors. In an era of data analytics, this means that simulation analysis has the tools to make use of such observations. Commercial simulation tools increasingly have the means to collect, store and make available this kind of detailed data for further analysis.

Simulation excels above all because it can be applied to such a diverse set of applications. Applications in manufacturing, healthcare, military and business operations, and transportation were among the applications presented at the earliest Winter Simulation Conferences [3]. They remain important areas of interest to this day based upon both conference papers and the applications cited on the developer’s webpages as case studies, white papers or tutorials. More recent applications have included homeland security and the threat of terrorist attacks, all modes of transportation and their interfaces, logistics and supply chains, investment tools, and computer and communications systems – the list is endless. New areas include cyber physical systems, which combine communications, embedded computing and physical systems such as autonomous vehicles of all kinds.

The Survey

This survey is the 10th biennial survey of simulation software for discrete-event systems simulation and related products [2]. All product information has been provided by the vendors. Products that run on personal computers to perform discrete-event simulation have been emphasized, since these are the most suitable for usage in management science and operations research. Simulation products whose primary capability is continuous simulation (systems of differential equations observed in physical systems) or training (e.g., aircraft and simulators) are omitted here.

There are 28 products listed in the survey, taken from 17 vendors who submitted for the survey by the deadline, once again surpassing the last survey. The range and variety of these products continues to grow, reflecting the robustness of the products and the increasing sophistication of the users. The information elicited in the survey from the vendors is intended to provide a general gauge of the product’s capability, special features and usage. This survey includes information about experimental run control (e.g., experimental design and automated scenario run capabilities) and special viewing features, including the ability to produce animations or demonstrations that can run independent of the simulation software itself. A separate listing gives contact information for all of the vendors whose products are in the survey. The vendor directory and survey data are available on the INFORMS OR/MS Today website (see editor’s note), and it will include vendors who missed the publishing deadline. Of course, most of the vendors provide their own websites with further details about their products. Many of the vendors also have active user groups that share experience in the specialized use of the software and are provided with special access to training and program updates.

There are a number of technical and professional organizations and conferences devoted to the application and methodology of simulation. The INFORMS publications Management Science, Operations Research and INFORMS Journal on Applied Analytics (formerly Interfaces) publish articles on simulation. The INFORMS Simulation Society sponsors simulation sessions at the national INFORMS meeting and makes awards for both the best simulation publication and recognition of service in the area, including the Lifetime Achievement Award for service to the area of simulation. Further information about the Simulation Society can be obtained from the website (https://connect.informs.org/simulation/home). This site also contains links to many vendors of simulation products and sources of information about simulation, simulation education and references about simulation. The Society for Modeling and Simulation International (www.scs.org) is devoted to all aspects of simulation. It holds conferences in the spring, summer and fall that cover all aspects of simulation practice and theory. The AlaSim International Conference is a relatively new conference hosted in Huntsville, Ala., with a focus on DOD and other government applications of simulation. The next conference is scheduled for October 24.

The INFORMS Simulation Society and the Society for Modeling and Simulation are both sponsors of the annual Winter Simulation Conference. This year’s conference, the 52nd in the series, will be held Dec. 8-11 in National Harbor, Md. Further information and registration information is available from the WSC site (www.wintersim.org). This site also links to the complete contents of the “Proceedings of the Winter Simulation Conference” from 1968 to 2018 for ready access to research and applications of simulation.

Editor’s note: A directory of vendors who participated in this year’s simulation software survey is available online (https://pubsonline.informs.org/magazine/orms-today/2019-simulation-software-survey#vendors) along with summarized tables of the collected data including tool descriptions and capabilities, pricing and general information (https://pubsonline.informs.org/magazine/orms-today/2019-simulation-software-survey). Vendors who did not respond by the deadline can fill out and return the survey questionnaire (https://www.surveymonkey.com/r/2019Sim) and it will be added to the online listings.

References

1. Shettterly, Margot Lee, 2016, “Hidden Figures: The American Dream and the Untold Story of the Black Women Mathematicians Who Helped Win the Space Race,” HarperCollins Publishers.
2. Swain, J. J., 2017, “Simulation: New and Improved Reality Show,” OR/MS Today, Vol. 44, No. 5, pp. 38-49.
3. Schriber, T.J., Reitman, J., Ockene, A., and Hixson, H.G., 2017, “History of the Winter Simulation Conference: Origins and early years (1967-1974),” Proceedings of the 2017 Winter Simulation Conference, W. K. V. Chan, A. D’Ambrogio, G. Zacharewicz, N. Mustafee, G. Wainer and E. Page, eds.
4. Hill, R. R., and Miller, J. O., 2017, “A History of United States Military Simulation,” Proceedings of the 2017 Winter Simulation Conference, W. K. V. Chan, A. D’Ambrogio, G. Zacharewicz, N. Mustafee, G. Wainer and E. Page, eds.
5. Friedman, Norman, 2017, “Winning a Future War: War Gaming and Victory in the Pacific War,” Department of Defense, Department of the Navy, Naval History and Heritage Command.
6. Sargent, Robert G., 2017, “A perspective on fifty-five years of the evolution of scientific respect for simulation,” Proceedings of the 2017 Winter Simulation Conference, W. K. V. Chan, A. D’Ambrogio, G. Zacharewicz, N. Mustafee, G. Wainer and E. Page, eds.