Live, virtual, and constructive


Live, Virtual, & Constructive Simulation is a broadly used taxonomy for classifying Modeling and Simulation. However, categorizing a simulation as a live, virtual, or constructive environment is problematic since there is no clear division among these categories. The degree of human participation in a simulation is infinitely variable, as is the degree of equipment realism. The categorization of simulations also lacks a category for simulated people working real equipment.

Categories

The LVC categories as defined by the United States Department of Defense in the Modeling and Simulation Glossary as follows:
  • Live - A simulation involving real people operating real systems. Military training events using real equipment are live simulations. They are considered simulations because they are not conducted against a live enemy.
  • Virtual - A simulation involving real people operating simulated systems. Virtual simulations inject a Human-in-the-Loop into a central role by exercising motor control skills, decision making skills, or communication skills.
  • Constructive - A simulation involving simulated people operating simulated systems. Real people stimulate such simulations, but are not involved in determining the outcomes. A constructive simulation is a computer program. For example, a military user may input data instructing a unit to move and to engage an enemy target. The constructive simulation determines the speed of movement, the effect of the engagement with the enemy and any battle damage that may occur. These terms should not be confused with specific constructive models such as Computer Generated Forces, a generic term used to refer to computer representations of forces in simulations that attempts to model human behavior. CGF is just one example model being used in a constructive environment. There are many types of constructive models that involve simulated people operating simulated systems.
Other associated terms are as follows:
Other definitions used in LVC discussions
  1. Enterprise: a project or undertaking that is especially difficult, complicated, or risky
  2. * A: a unit of economic organization or activity; especially: a business organization
  3. * B: a systematic purposeful activity
  4. Environment: The aggregate of surrounding things, conditions or influences; surroundings
  5. Construct: To make or form by combining or arranging components
  6. Component: One of the parts of something
Current and emerging technology to enable true LVC technology for Combat Air Forces training require standardized definitions of CAF LVC events to be debated and developed. The dictionary terms used above provide a solid foundation of understanding of the fundamental structure of the LVC topic as applied universally to DoD activities. The terms and use cases described below are a guidepost for doctrine that uses these terms to eliminate any misunderstanding. The following paragraph uses these terms to layout the global view, and will be explained in detail throughout the rest of the document. In short:
Central to a functionally accurate understanding of the paragraph above is a working knowledge of the Environment definitions, provided below for clarity:
  • Live Environment *: Warfighters operating their respective disciplines’ operational system in a real-world application
  • Virtual Environment *: Warfighters operating fielded simulators or trainers
  • Constructive Environment *: Computer Generated Forces used to augment and force multiply Live and/or Virtual scenario development
The Environments by themselves are generally well understood and apply universally to a diverse range of disciplines such as the medical field, law enforcement or operational military applications. Using the medical field as an example, the Live Environment can be a doctor performing CPR on a human patient in a critical real world situation. In this same context, the Virtual Environment would include a doctor practicing CPR on a training mannequin, and the Constructive Environment is the software within the training mannequin that drives its behavior. In a second example, consider fighter pilot training or operational testing. The Live environment is the pilot flying the combat aircraft. The Virtual environment would include that same pilot flying a simulator. The constructive environment includes the networks, computer generated forces, and weapons servers, etc. that enable the Live and Virtual environments to be connected and interact. Although there are clearly secondary and tertiary training benefits, it is important to understand combining one or more environments for the purpose of making Live real world performance better is the sole reason the LVC concept was created.
However, when referring to specific activities or programs designed to integrate the environments across the enterprise, the use and application of terms differ widely across the DoD. Therefore, the words that describe specifically how future training or operational testing will be accomplished require standardization as well. This is best described by backing away from technical terminology and thinking about how human beings actually prepare for their specific combat responsibilities. In practice, human beings prepare for their roles in one of three Constructs: Live, in a Simulator of some kind, or in other Ancillary ways. Actions within each of the Constructs are further broken down into Components that specify differing ways to get the job done or achieve training objectives. The three Constructs are described below:

Live Construct

Live is one of three constructs representing humans operating their respective disciplines’ operational system. Operational system examples could consist of a tank, a naval vessel, an aircraft or eventually even a deployed surgical hospital. Three components of the Live Construct follow
  • Live vs. Live: Traditional Live vs. Live training is a component of the Live Construct and occurs when Live operational systems interact with one another to augment scenario complexity
  • LC: Live, Constructive is a component of the Live Construct whereby CGFs are injected into Live operational systems in a bi-directional, integrated, secure, dynamically adaptable network to augment scenario complexity
  • LVC: Live, Virtual and Constructive is a component of the Live Construct whereby Virtual entities and CGFs are injected into Live operational systems in an integrated, secure, dynamically adaptable network to augment scenario complexity

    Simulator Construct

The Simulator Construct is a combination of Virtual and Constructive, and is composed of humans operating simulated devices in lieu of Live operational systems. The Simulator Construct consists of three components:
  • A locally networked set of identical simulators typical of the environment
  • A networked set of disparate simulators
  • A locally closed-loop networked enclave of multiple simulator devices in support of High-End Testing, Tactics, and Advanced Training

    Ancillary Construct

Is the third construct other than Live or Simulator whereby training is accomplished via many components
  • Computer-based instruction
  • Self-study
  • Platform instructed academics
Utilizing the definitions above, the following table provides a graphical representation of how the terms relate in the context of CAF Training or Operational Test:
Using the figure above as a guide, it is clear LVC activity is the use of the Virtual and Constructive environments to enhance scenario complexity for the Live environment – and nothing more. An LVC system must have a bi-directional, adaptable, ad-hoc and secure communication system between the Live environment and the VC environment. Most importantly, LVC used as a verb is an integrated interaction of the three environments with the Live environment always present. For example, a Simulator Construct VC event should be called something other than LVC. In the absence of the Live environment LVC and LC do not exist, making the use of the LVC term wholly inappropriate as a descriptor.
As the LVC Enterprise pertains to a training program, LVC lines of effort are rightly defined as “a collaboration of OSD, HAF, MAJCOM, Joint and Coalition efforts toward a technologically sound and fiscally responsible path for training to enable combat readiness.” The “lines of effort,” in this case, would not include Simulator Construct programs and development but would be limited to the Construct that includes the LVC Enterprise. The other common term, “Doing LVC” would then imply “readiness training conducted utilizing an integration of Virtual and Constructive assets for augmenting Live operational system scenarios and mission objective outcomes.” Likewise, LVC-Operational Training or “LVC-OT” are the tools and effort required to integrate Live, Virtual and Constructive mission systems, when needed, to tailor robust and cost-efficient methods of Operational Training and/or Test.