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5.1: Categories of Simulations

Difficulty Level: At Grade Created by: CK-12
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Lesson Objectives

  • Describe the spectrum of modeling and simulation training activities.
  • Describe a live simulation environment and give an example in the context of training.
  • Describe a virtual simulation environment and give an example in the context of training.
  • Describe a constructive simulation environment and give an example in the context of training.


Bloom’s Taxonomy
A classification of the levels of intellectual behavior important in learning, developed in 1956 by a group of educational psychologists led by Benjamin Bloom. During the 1990s, a new group of cognitive psychologists, led by Lorin Anderson (a former student of Bloom), updated the taxonomy, reflecting relevance to 21st century work.
cognitive skills
Mental skills that are used in the process of acquiring knowledge. These skills include reasoning, perception, and intuition.
Modeling and simulation that involves simulated people operating simulated systems. This includes human or non-human systems using behavior models in a synthetic environment. Real people stimulate (make inputs to) such simulations but are not involved in determining the outcomes.
embedded training
Modeling and simulation involving real people using a real weapons system in training mode using embedded software and/or hardware.
Modeling and simulation involving real people operating real systems in a real environment. Sometimes the real weapons systems can be replaced by simulated weapons systems (e.g., laser tag weapons and sensors or paintball) for safe training with live human targets. This is called a tactical engagement simulation system and can include laser transmitters instead of bullets, larger rounds, or shorter-range guided weapons such as anti-tank missiles.
mathematical model
Model that uses mathematical symbols and relationships to describe something (e.g., formulas or historical data).
Application of a standard, rigorous, structured methodology to create and validate a physical, mathematical, or otherwise logical representation of a system, entity, phenomenon, or process.
physical model
Model whose physical characteristics resemble those of the item being modeled. In other words, it looks and feels like the real thing (e.g., airplane, statue, or house).
process model
Model that describes the steps needed to be followed to get things done (e.g., to do list or flow chart).
simulation fidelity
The simulation's degree of realism. Simulation fidelity can be measured subjectively or objectively. Subjective measurements include use of questionnaires or evaluation forms submitted by the users of the simulation. Objective measurements include measuring physiological responses and reflexes (e.g., change in blood pressure or heart rate, increased respiration rate, and task performance) of the users of the simulation.
synthetic environment
Environment that may be created within a single computer or a vast distributed network connected by local and wide area networks and augmented by super-realistic special effects and accurate behavioral models. They allow visualization of and immersion into the environment being simulated.
synthetic human-made environment
Representation of human-made structures like buildings, bridges, and roads.
synthetic natural environment
Representation of climate, weather, terrain, oceans, space, and features (e.g., forest, lakes, roads, bridges, or buildings) that exist in this environment.
synthetic psychological environment
Representation of psychological influences on individuals and/or groups based on demography and other cultural factors.
Modeling and simulation involving real people operating simulated systems in a synthetic environment. Virtual simulations inject human-in-the-loop in a central role by exercising motor control skills (e.g., flying an airplane), decision skills (e.g., firing or not firing a weapon in a combat game), or communication skills (e.g., as members of a command staff or team in a combat game).

Check Your Understanding

Drawing on Student Experiences

Many of us have been involved in sports or other activities that require practice to improve skills and gain experience and confidence. This is actually a form of live training that may or may not involve the use of modeling and simulation. So a practice game can be a live simulation of a real game — real people using real equipment.

Similarly, many of us enjoy the challenge in playing first-person shooter video games. This is a form of a virtual simulation, where real people operate simulated systems in a synthetic environment. Often, we are playing the game against computer generated adversaries. If so, this video game is incorporating a constructive simulation, where simulated people (or things) are operating simulated systems or weapons that they can use to fire at us (virtually, of course).


Live, virtual, and constructive (LVC) is a broadly used taxonomy for classifying modeling and simulation. However, categorizing a simulation as live, virtual, or constructive can at times be misleading, since the boundaries between these categories are not always clear. Complicating matters further, the degree of human participation in a simulation, as is the degree of equipment realism, can be infinitely variable.

Lesson Content

Live Modeling and Simulation

Although complex with respect to exercise coordination and expense, live simulations are used extensively in military training. This type of training involves real people operating real systems (e.g., a pilot flying an aircraft and dropping real bombs on a practice target or an infantry squad shooting real bullets at practice targets). To make the training more economical and safer, real weapons systems are sometimes augmented or replaced with tactical engagement simulation (TES) equipment. An example is an infantry exercise using multiple integrated laser engagement system (MILES), which replaces real bullets with blanks and a laser. Other soldiers or adversaries carry laser receivers scattered on their bodies that detect when they have been hit by a firearm’s laser. Another example would be replacing real bullets with paintball rounds. The following video shows a live simulation of the Marine Corps Immersive Infantry Trainer (IIT) at Camp Pendleton, CA. Notice in part of the video a small squad of Marines entering a room and reacting to a projected image of a bad guy on the wall. When the Marines fire paintball rounds at the projected image on the wall, the wall has sensors that detect the hit, and the virtual bad guy falls down. The projected image of a bad guy is a virtual simulation that interfaces with the live simulation (paint ball rounds detected by the wall sensor). This is an example of how you can augment a live training exercise with a virtual simulation.

Infantry Immersion Trainer (IIT) at Camp Pendleton at http://www.youtube.com/watch?v=BR8Vg6FWAGg (3:37)

Virtual Modeling and Simulation

Virtual simulations provide a more economical alternative for certain tasks to live M&S. This type of training involves real people operating simulated systems. It allows the user to exercise motor control and decision making or communication skills (e.g., operating a simulated space shuttle or a simulated aircraft, firing simulated weapons at simulated targets). The following Figure below is an early but advanced virtual simulation example. It is a 1969 picture of the Apollo simulator.

Apollo Simulator (Courtesy of Hank Okraski)

The following video shows a virtual simulation example of the EST–2000 simulator used by the Army National Guard that makes use of the laser based TES equipment.

Virtual Combat Simulator for the National Guard at http://www.youtube.com/watch?v=eFtRiwINCUs (2:00)

Constructive Modeling and Simulation

Constructive simulations have been used by the military to conduct "what if" scenarios and exercises, normally with aggregated forces (cluster of computer generated platoon, company, battalion, etc.). They allow the military leadership to quickly test or validate new tactics or procedures. Constructive simulations can also be used in training exercises to augment live or virtual simulations. This type of training involves simulated people or entities (e.g., tank or aircraft) operating simulated systems. Real people stimulate (provide input to) these simulations but are not involved in determining the outcomes. The simulated entities use behavior models to determine the overall outcome of the simulation. The following video shows a mobile application use of the Army’s One Semi-Automated Forces (OneSAF) constructive simulation.

http://www.youtube.com/watch?v=sodV0rVxvRY (1:33)

Spectrum of Modeling and Simulation Training Activities

LVC simulations used in training can be used to cover a wide spectrum of activities at varying levels of fidelity and complexity. Using a common military term, "crawl, walk, run" describes a logical progression in training that optimizes human learning and performance, the goal being to apply the right mix of simulation and training based on the student’s intellectual progression. In this military training example we apply a "learning ladder" approach that is an adaptation of Bloom’s Taxonomy in learning behavior (Figure below).

  1. Computer Augmented Learning (using virtual simulation): In this example an infantry soldier begins his training in the classroom using instructor-led training (ILT) and computer-based interactive multimedia instruction (IMI). At this stage the soldier learns fundamental knowledge.
  2. Specialized Task Training (using virtual and constructive simulation): The IMI can include higher level simulations like first-person shooter games. These serious games typically involve the student operating simulated weapons in a synthetic environment (i.e., virtual simulation) where a computer generated adversary is operating simulated systems like a weapon (i.e., constructive simulation).
  3. Visual and Cognitive Immersion (using virtual and constructive simulation): The student then progresses by applying what he has learned and incorporating decision skills. The student does this by networking the serious game with other students, acting as an infantry team.
  4. Multi-sensory Immersive (using virtual and constructive simulation): The student then progresses by applying what he has learned and incorporating fine motor skills and enhanced decision-making skills. The student does this by using realistic simulated weapons systems (versus a joystick or mouse) in an immersive training environment (ITE) networked with other students in an infantry squad. The sense of realism and complexity has now increased, along with the hardware cost.
  5. Hybrid "Crew" Stations (using virtual and constructive simulation): This exercise involves networking more than one infantry squad ITE across the internet forming a multi-player online ITE (MITE). This is the apex of cognitive skill development and exercise complexity, short of using a large-scale live training exercise.
  6. Operational Systems (using LVC simulation): This is the highest operational fidelity available for training, short of an actual military operation. The complexity and cost can be quite large depending on the number and type of LVC simulations integrated or working together in the exercise. For example, you could have one infantry squad in an ITE (virtual and constructive simulation) working in concert with an infantry squad using TES weapons systems in a live training environment (live simulation), all provided air cover by a pilot in a flight simulator (virtual simulation). Further, it is possible to embed training features or objects in operational equipment, such as generating targets for an operator to practice in a "training mode."

Learning Ladder

Lesson Summary

  • Live modeling and simulation training is very complex and usually very expensive. Sometimes you can enhance a live training exercise with virtual or constructive simulations.
  • Virtual modeling and simulation training is computationally complex but usually more economical than live training. Usually a first-person-shooter game (virtual simulation) is combined with a computer generated adversary (constructive simulation).
  • Constructive modeling and simulation is best used for developing strategy and tactics and to enhance virtual or live training.
  • LVC simulations can be used in a spectrum of activities to provide the optimal mix for learning.
  • LVC simulations can be networked to provide greater complexity and higher levels of learning.
  • Live simulations, networked with virtual and constructive simulations, form the highest level of operational fidelity and complexity.

Review Questions

  1. Give an example of a mixture of live, virtual, or constructive simulations used during training.
  2. How do you introduce motor skills learning using virtual or constructive simulations?
  3. How do you introduce motor skills learning using live simulations?

Further Reading / Supplemental Links

Points to Consider

Modeling and simulation used for military training can cover a wide spectrum of activities.

  • What type of simulation is most realistic?
  • What type of simulation is usually the least expensive to use for training?
  • What type of simulation is associated with first person shooter games?

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Date Created:
Jul 27, 2012
Last Modified:
Apr 29, 2014
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