Systems Modeling & Simulation Working Group

The following was compiled by members of the Systems Modeling & Simulation Working Group to provide the model-based systems engineering community with a common set of shared terms and definitions.

A-C | D-F | G-I | J-L | M-O | P-R | S-U| V-X | Y-Z

Terms & Definitions (G-I)


Term Definition Source
Hardware In-The-Loop Simulation Simulation and simulators that employ one or more pieces of operational equipment (to include computer hardware) within the simulation/simulator system. (DoD M&S Human Capital Strategy) Modeling & Simulation Coordination Office
Hardware-in-the-Loop Testing (HiL) A type of dynamic simulation that includes one or more actual system components operating in conjunction with simulated components. Kossiakoff et al.
Hierarchical Model A model in which superior/subordinate relationships are represented, often as trees of records connected by pointers. Modeling & Simulation Coordination Office
High Level Architecture (HLA) A family of related standards that describe a unified approach and common architecture used to construct interoperable simulation systems as standardized in IEEE 1516. Modeling & Simulation Coordination Office
Human-In-The-Loop Simulation Simulation and simulators that employ one or more human operators in direct control of the simulation/simulator or in some key support function. (DoD M&S Human Capital Strategy) Modeling & Simulation Coordination Office
Implementation The means by which a model or simulation or portions of a model or simulation is realized. (SISO-REF-020-2007) Modeling & Simulation Coordination Office
INCOSE The International Council on Systems Engineering (INCOSE) is a not-for-profit membership organization founded to develop and disseminate the interdisciplinary principles and practices that enable the realization of successful systems. Their mission is to share, promote and advance the best of systems engineering from across the globe for the benefit of humanity and the planet. Their vision is to be the world's authority on Systems Engineering. INCOSE
Independent Variable A variable whose value is not dependent on the values of other variables. Contrast with: dependent variable. (IEEE 610.3-1989) Modeling & Simulation Coordination Office
Independent Verification And Validation (IV&V) The conduct of verification and validation of a model, simulation, and associated data by an individual, group, or organization that did not participate in the development and is not in the same chain of command or organization as the developer. Modeling & Simulation Coordination Office
Information Model A model that represents the processes, entities, information flows, and elements of an organization and all relationships between these factors. Modeling & Simulation Coordination Office
Initial Condition The values assumed by the variables in a component, system, model, or simulation at the beginning of some specified duration of time; initial state. (SISO-REF-002-1999) Modeling & Simulation Coordination Office
Input The externally supplied data to which a simulation responds and from which it calculates its output (e.g., operator controls, weapon detonation, wind speed, and direction). (SISO-REF-002-1999) Modeling & Simulation Coordination Office
Integration A process that combines system elements to form complete or partial system configurations in order to create a product specified in the system requirements. ISO/IEE 2008
Integration DEFinition for Functional Modeling (IDEF) A multiple page (view) model of a system that depicts functions and information or product flow. Boxes illustrate functions and arrows illustrate information and product flow. Alphanumeric coding is used to denote the view. IDEF0 - functional modeling method IDEF1 - information modeling method IDEF1X - data modeling method; IDEF3 - process description capture method IDEF4 - object oriented design method IDEF5 - ontology description capture method
Intellectual Property Intangible property that is the result of creativity, such as patents, trademarks, or copyrights. (DoDI 5000.70) Modeling & Simulation Coordination Office
Interface Requirement Constraint which defines how the system is required to interact with external systems (external interface), or how system elements within the system, including human elements, interact with each other (internal interface). SEBok
Internal & External Interface Requirement See Interface Requirement SEBok
Interoperability The ability of a model or simulation to provide services to and accept services from other models and simulations, and to use these exchanged services to operate effectively together. (SISO-REF-002-1999) Modeling & Simulation Coordination Office