Software Survey: Simulation: a better reality?
Imagine the world as it is and what it might be: biennial survey of discrete-event simulation software tools.
Screen shot simulation of airport capacity.
Image courtesy of Simio.
By James J. Swain
Simulation provides an unparalleled capability to imagine the world as it is and as it might be – a better world of efficient production, responsive supply chains and ideal healthcare delivery. The varied tools in this software survey provide a diverse set of products that allow analysts to build, view and analyze complex models for a wide range of applications. Moreover, as the culmination of over a half-century of development, simulation is far more than the “tool of last resort” as it was once described. Simulation is now a mature technology that permits varied, complex and detailed studies of the world as it might be.
Simulation software benefits from the converging development of software and hardware. Simulation modeling is by its nature computationally intensive. An analytical model might be reduced to a convenient formula, but simulation derives its flexibility through the direct construction of sample realizations of the complete process under study, most often replicated and repeated for other parameters or configurations. Indeed, when simulation is employed within an optimization process, the number of replications can rapidly increase. The widespread availability of both personal and Web-based computation is essential to simulation and makes analysis available to all.
These tools are designed to assist the user in building the model, which is a description of reality as it is or is imagined to be, but the model is then used to spell out in detail how that reality is likely behave, as well as the permit estimation of the variability. Moreover, each tool contains visual tools that also depend upon access to sophisticated visualization tools such as three-dimensional rendering of the model results.
Survey Directory & Data
|To view the directory of simulation software vendors,
software products and survey results, click here.
The tools in this survey are largely devoted to the discrete event simulation, suitable for a huge range of real world problems that range from services, manufacturing, transportation and supply chains, military operations or logistics, communications and even computer processing. Some tools are designed for a general class of modeling problems, while others focus on applications in focused areas such as manufacturing, service industries or healthcare – in the latter case note the Flexsim Healthcare product, while ProModel has specialized MedModel and Patient Flow Simulators, for example. Many of the general simulators have the capability to build up specialized templates or libraries, so that organizations can construct their own specialized models that build on accumulated modeling experience and knowledge.
As simulation tools grow have matured, it has also become apparent that simulation provides more than the ability to fill in the gaps in mathematical analysis. For instance, analytical models may be limited by restrictive assumptions, or provide some aspects of a system but not others. For instance, many queueing models provide steady-state means but less detailed information about the variability of the process. More critically, simulation provides the capability to visually demonstrate system behaviors, which is critical for communication, analysis, marketing and often for model verification and validation. Certainly visualization speaks to a wider audience than most statistical summaries, no matter how well displayed!
Increases in computing power combined with improvements in analysis and simulation random process “infrastructure” also means that modern simulation products are capable of providing more precise answers. Simulation results are statistical estimates, but improvements in analysis combined with the power to obtain significant replications have greatly improved the precision of both statistical estimates and the power of comparisons among different scenarios. The vendors have exploited research and development in computation and analysis to refine their products.
Simulation is likely the most used tool for analysis of new systems. The combination of flexibility, accuracy and visualization is a powerful combination that makes analysis accessible and understandable to a wide audience. The idea of simulation is commonplace: examples include both sports and realistic role playing games, while many forensic shows include depictions of simulations of how crimes were committed based on the available evidence. Likewise, the widespread use of realistic animation in entertainment also makes the acceptance of simulation natural.
This survey is the ninth biennial survey of simulation software for discrete event systems simulation and related products originally published in OR/MS Today . 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 43 products listed in the survey, taken from 23 vendors who submitted for the 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. The 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. To see a directory of participating vendors along with the survey results, click here. The Lionheart Publishing website (www.lionheartpub.com) 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 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 website www.informs-cs.org. 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 also devoted to all aspects of simulation. Their conferences include two annual multi-conferences, SpringSim and SummerSim, which cover all aspects of simulation practice and theory. In Huntsville, Ala., a relatively new simulation conference is being organized, the AlaSim International Conference, and the second conference is scheduled for May 2014.
The INFORMS Simulation Society and the Society for Modeling and Simulation are both sponsors of the annual Winter Simulation Conference. This year’s conference will be held Dec. 8-11 in Washington, D.C. As in past years, the conference will be held together with the Modeling and Analysis of Semiconductor Manufacturing (MASM) conference. Further information and registration information is available from the website www.wintersim.org. This site also links to the complete contents of the Proceedings of the Winter Simulation Conference from 1968 to 2012 for ready access to research and applications of simulation.
Screen shot simulation of a bottling line.
Image courtesy of FlexSim Software.
The range of simulation applications can be explored through published sources such as the Proceedings of the Winter Simulation Conference and many of the vendor websites. The latter serve to illustrate the range of the products and to provide illustrations about the application of the software, typical means of analysis and success gained from simulation.
As manufacturing has become outsourced overseas, logistics, supply chains and transportation have become more critical and have been a frequent object of simulation study. This is a reflection of the critical importance of these logistical issues to retailers and manufacturers to ensure the timely delivery of products and components at a competitive cost. Simulation has been used to study all aspects of transporting cargo within the supply chain, whether by ship, barge, truck or train, or managing the operation of port terminals and distribution centers. Some studies focus on the overall operations of large networks, while other simulations have examined the optimal way to route trucks to loading docks within regional distribution centers.
Newer technologies such as RFID labeling have been studied using simulation, and their use examined within the warehouse as well as their potential effect on the overall supply chain. Likewise, once items reach the factory, they may be stocked to await use. Automated retrieval systems may be used and often optimized after study by simulation. Finally, simulation may be used to examine the information system that supports the supply chain, or perhaps to determine ways to quantify risk within the system and to devise strategies to ameliorate risk within the logistics chain.
Simulation has been used for decades to study, improve and optimize manufacturing processes and operations. This is reflected in many of the products in this survey that most often provide support for manufacturing problems in their design and their animation features. This continues to be an important area of simulation analysis that now includes both lean manufacturing initiatives and six sigma studies.
The military has used simulation for decades to design weapons, sensors and other devices to study their capabilities and their employment in combination with other systems, and then to define changes in operations, doctrine and training. Simulation is increasingly used in non-military settings to examine security in a variety of settings, such as airports, power plants and public venues such as large entertainment and sporting events. Simulation analysis has been extended to emergency planning of all kinds, whether it is the need to evaluate an evacuation plan or to plan an emergency response in the aftermath of a natural disaster. The delivery of critical food or shelter items or delivery of medical support to designated receiving centers are among the studies that have been made using simulation.
Finally, healthcare has been an area of intense simulation study at every level. Simulation has looked at staffing and scheduling, in emergency rooms and outpatient clinics, surgery units, lab testing units and even medical supplies logistics. Since healthcare has a major contribution to the GDP and is a the subject of an ongoing national policy debate, it is safe to say that it will remain an area of active study for decades to come, and simulation will remain a valuable tool for this study. It is a challenge that simulation is more than capable of handling.
James J. Swain (firstname.lastname@example.org) is a professor and chair of the ISEEM department at the University of Alabama in Huntsville, and a senior member of INFORMS.
- Swain, James. J. , 2013, “Simulation: A better reality?” OR/MS Today, Vol. 40, No. 5, pp. 48-50 (October 2013).