Software Survey: New Frontiers in Simulation
Biennial survey of discrete-event simulation software tools
Image courtesy of Wolverine Software
by James J. Swain
We use simulation to realize our imagination in a specific and detailed way — rendering what we imagine in a way that we can grasp. For instance, one may use laser devices to simulate the effect of actual arms during a military exercise, while preserving the dust, heat and fatigue that soldiers experience during actual operations; or simulate the equations of motion to provide the sensation of flying an airliner under adverse conditions to prepare a pilot to deal with an emergency; or model the interactions among producers and suppliers to predict the performance of an international supply chain. However we use it, simulation tools are there to aid our imagination to probe the frontiers of knowledge, to teach or simply to entertain.
Simulation has grown ubiquitous: the widespread availability of personal computers (and gaming computers) means that everyone has access to this technology. In the last decade simulation has moved out of the classroom and lab and into the public domain, becoming widely familiar and accepted though games and movies. This emergence into the public consciousness has already opened new business opportunities and will no doubt open new frontiers for the application of simulation.
The migration of simulation into the public arena over the last decade may prove to be the most significant recent change in the field. For most of the history of simulation, specialized technical applications have driven the development of simulation, which tended to limit the field’s growth. By contrast, commercial simulation products in entertainment open lucrative new markets that may very well spur an increasingly rapid pace of innovations. Academic programs are now being offered to train the next generation of games developers. Simulation has not had a large impact on the classroom as yet, but advances in gaming will contribute to development of simulation-based teaching tools.
The widespread availability of simulation technology also means novel fields of application. For instance, psychologists are using existing military games as the basis for a treatment of Post Traumatic Stress Disorder (PTSD). One treatment approach is exposure therapy, in which stressful situations are relived in such a way that they can be faced. One advantage of simulation is that the exposure can be graduated, allowing the patient to approach the stressful memory slowly, through different levels of detail and intensity. One tool in development for Iraq War veterans includes virtual reality immersion complete with sounds, a shaker platform that provides vibration to simulate the passage of a helicopter flying overhead or nearby explosions, and even scents that can be used to complete the sensations associated with the memory. The treatment is made possible by the existing simulation games and virtual reality components that drastically reduce the cost of development.
Simulation-based training is already in use for commercial applications, such as specialized maintenance activities for aircraft equipment. Simulation-based instruction is not yet widespread in the college classroom. Yet, games such as America’s Army illustrate that simulations can be used to immerse the players within a realistic simulated environment that can be used for role-playing. Many of these games are also structured to provide interaction between multiple players. Immersive activities might be developed that provide a context for problem-solving in a course such as design of experiments or quality control in statistics, model formulation and application in operations research or engineering design. Such an immersive approach would provide both more realism and also match the interactive activities that the current generation is used to.
The accompanying online survey (www.lionhrtpub.com/orms/surveys/Simulation/Simulation.html) is the eighth biennial survey of simulation software for discrete-event systems simulation and related products (Swain, 2005). 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.
Forty-eight products are listed in the survey, taken from 65 products submitted, making it one of the larger surveys. 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 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., batch run or experimental design capabilities) and special viewing features, including the ability to produce animations or demonstration 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.An expanded version of the survey is available on the Lionheart Publishing Web site (www.lionhrtpub.com) and will include vendors who missed the publishing deadline. Of course, most of the vendors provide their own Web sites with further details about their products.Many of the vendors also have active users groups that share experience in the specialized use of the software and are provided with special access to training and program updates.
A number of technical and professional organizations and conferences are devoted to the application and methodology of simulation. The INFORMS publications Management Science, Operations Research and 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 Web site www.informs-cs.org. This site now provides the complete contents of the Proceedings of the Winter Simulation Conference from 1997 to 2006, and 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 also devoted to all aspects of simulation. Their conferences include the Huntsville Simulation Conference that takes place annually in Huntsville, Ala.
The Simulation Society and the Society for Modeling and Simulation are sponsors of the annual Winter Simulation Conference (WSC). The 2008 WSC will be held Dec. 7-10 at the InterContinental Hotel in Miami. The program includes tutorial, methodology and applications tracks, including specialized areas such as computer modeling, financial models, transportation and logistics and other operations. Further information and registration information is available from the site www.wintersim.org.The sponsors of the conference are also ready sources of information about simulation.
Legacy of Simulation: Ancient Roots, Modern Application
The use of simulation is so central to the modern Department of Defense (DoD) that there is probably no aspect of procurement, operations or doctrine that is not currently studied by simulation. Simulation is also used extensively in training. The DoD has extensively invested in all aspects of distributed simulations, where models of individual fighting units of all types are joined to models that determine what sensors (such as radar) can “see,”how communications will perform under field conditions, and how command and control will function. The DoD has evolved standards for validation and model certification, and is actively exploring the means for the effective reuse of code developed in one model for use in other, newer models.Visualization has also been brought to a high level of development to make training as realistic as possible.
The reliance on simulation is anything but new – the military has used gaming for several centuries to train its officers, to plan future operations and to perform staff studies to update doctrine.Military war gaming using sand tables and maps using various counters to represent bodies of troops predate computer models. A major limitation was the manual evaluation of casualties units using dice and special tables. Our own military academies included war gaming into their curriculum from their inception.
The rapid changes in technology during the last century necessitated ongoing studies to determine how the new weapons could be utilized and to provide an appreciation of their effectiveness. For instance, during the interwar period many nations formed experimental armored units to study the size, composition and operations of the new units. Many of these units evolved from exclusively armored formations to the combined arms units that predominated during WWII. Likewise, the U.S.Navy conducted a series of fleet exercises in the Pacific in the 1930s to study the effectiveness and the proper role of aircraft carriers. Over time, these studies led to an appreciation of their offensive capability and a transformation in naval doctrine. For instance, Fleet Exercise XIX in March of 1938 presaged the attack on Pearl Harbor,when planes from the Saratoga simulated a pre-dawn attack on aircraft at Hickam and Wheeler air fields in Hawaii. These exercises had a definite impact on naval thinking that prepared officers and planners for the conduct of operations in the Pacific during WWII.
The phenomenal growth of simulation throughout industry and particularly within the DoD has led to a growing demand for simulation professionals to develop models and modeling tools, and to manage large and complex simulation based projects.Academic programs in modeling and simulation have appeared at the University of Arizona,University of Central Florida, Old Dominion University, Georgia Tech and the University of Alabama in Huntsville, among others. Organizations such as the Alabama Modeling and Simulation Council (www.amsc.to) have been formed to represent all aspects of simulation, including the commercial, technical standards and training, academics and applications.
Military and industrial operations rarely operate from a single symphonic “score,” but more nearly resemble improvisations among interacting players. A limitation of the traditional simulation has been the limits on autonomy provided in the modeling constructs. Even entities that represent workers typically operate by rules that are not dissimilar to those of the machines. For instance, in a typical manufacturing simulation, products may be pushed through the system using a schedule of orders to be processed.Workers tend to individual or groups of machines according to well-defined rules, priorities and characteristics of the work. Few models provide any meaningful autonomy to make decisions, to learn from their environment or to cooperate with each other when problems arise.
Newer simulation products are beginning to provide autonomous agents that can act on their own and interact among themselves. These agent-based simulations (Samuelson and Macal, 2006) have evolved from earlier studies of complex systems whose behavior has defied easy explanation.Models of biological systems involving interacting members have been built to understand how these complex behaviors have led to social behaviors in foraging.Generalizing what has been learned from these studies has led to simulation agents with the ability to sense their surroundings, interact with other agents, reason and choose a course of action. Software has been developed that make it possible to program agents to sense their surroundings, learn, remember or to make decisions. One example is available in this survey, as the AnyLogic (XJ Technologies) software supports simulation agents.
Modeling using simulation agents is being applied in transportation and other areas where interaction and local decisionmaking might play an essential role.Agents have been used in traffic simulations, where driving behaviors are affected by local conditions, variations among drivers, and may include the decision to change routes based on traffic density and the awareness of alternative routings. Large simulations of air traffic include the provision for centralized traffic control and the autonomous control of their pilots. Other applications include crowd simulations, tactical warfare and pedestrian traffic.
James J. Swain (email@example.com) is professor and chair of the ISEEM department at the University of Alabama in Huntsville.
Editor’s note: We received more than 65 packages for this survey. Due to space constraints, we could only list 48 in the printed version of OR/MS Today. Among the submissions left out were multiple versions of simulation packages from certain vendors, packages that didn’t fit the parameters of the survey [such as Expert Fit (www.averill-law.com) and Stat::Fit (www.geerms.com), which are not actually simulation programs, though they support simulation] and packages that arrived after the deadline. A more complete list of packages, including those not seen here and those that arrived after the deadline, can be found online at: http://lionhrtpub.com/orms/surveys/Simulation/Simulation.html.
ANALYTICAL SOFTWARE SURVEYS
OR/MS Today (www.lionhrtpub.com/ORMS.shtml), the membership magazine of the Institute for Operations Research and the Management Sciences (INFORMS), regularly conducts surveys of software of interest to a broad spectrum of analysts. Most of the surveys are updated on a biennial basis.
Each survey includes a directory of vendors and side-by-side comparisons of software packages, including such metrics as system requirements, performance capabilities, key features, technical support and vendor comments.
Several software surveys are available online, including:
Vehicle Routing (February 2010)
Linear Programming (June 2009)
Statistical Analysis (February 2009)
Decision Analysis (October 2008)