3- D: Three-dimensional, refers to the visual display that exhibits breadth, height and thickness or depth.

6DOF: Six degrees of freedom, refers to the number of simultaneous directions or inputs a sensor can measure. Typically used to describe the combination of spatial positions (X, Y, Z) and orientation (roll, pitch, yaw).

absolute error: The absolute deviation, taken without regard to sign, from the corresponding true value.

absolute gravity: The acceleration of gravity directly determined by a device that measures time and length.

absolute orientation: The scaling and leveling to ground control (in a photogrammetric instrument) of a relatively-oriented stereoscopic model or group of models.

absolute positioning: A precise location. The determination of the position of a point with respect to the next positioned body, for example the center of mass of the Earth as defined in the DoD World Geodetic System.

absolute timestamp: An absolute timestamp is used when simulation application clocks are synchronized to Universal Coordinated Time (UTC).

absorbing Markov chain model: A Markov chain model that has at least one absorbing state and in which, from every state, it is possible to get to at least one absorbing state.

absorbing state: In a Markov chain model, a state that cannot be left once it is entered.

abstraction: 1. The process of selecting the essential aspects of a simuland to be represented in a model or simulation while ignoring those aspects that are not relevant to the purpose of the model or simulation. The set of elements produced by this process. 2. The act or process of separating the inherent qualities or properties of something from the actual physical object or concept to which they belong. 3. Process of generalization by reducing the information content of a concept or an observable phenomenon, typically in order to retain only information which is relevant for a particular purpose.

acceptance: The decision to use a simulation for a specific purpose. (See also "accreditation").

accessibility: The ease of approaching, entering, obtaining, or using.

accreditation: The official certification that a model, simulation, or federation of models and simulations and its associated data are acceptable for use for a specific purpose.

accreditation agent: The organization designated by the accreditation sponsor to conduct an accreditation assessment for an M&S application.

accreditation authority: The organization or individual responsible to approve the use of models, simulations, and their associated data for a particular application.

accreditation criteria: A set of standards that a particular model, simulation, or federation must meet to be accredited for a specific purpose.

accreditation plan: The plan of action for certifying a model, simulation, or simulation federation as acceptable for specific purposes. The accreditation plan specifies the reviews, testing, and other accreditation assessment processes, as appropriate, needed to certify that the model or simulation has met the acceptability criteria.

accreditation process: The procedure followed by the M&S application sponsor that culminates in the accreditation determination.

accreditation sponsor: The DoD Component or other organization with the responsibility for accrediting a model, simulation, or federation of models and/or simulations for a specific use or series of uses (e.g., for joint training or a Defense Acquisition Board milestone review).

accreditor: A role; a person, or an organization that accredits assets for use and reuse for specific purposes or categories of purposes. An accreditor is responsible for certifying that a federation has been verified and validated, and authorizes the use of the federation for its intended use.

accuracy: 1. The measure of the maximum deviation of an attribute or a parameter value in the simulation or federation from reality or some other chosen standard or referent. 2. The degree of conformity with a standard, or the degree of perfection attained in a measurement. Accuracy relates to the quality of a result, and is distinguished from precision, which relates to the quality of the operation by which the result is obtained and can be repeated. 3. The degree of exactness of a model or simulation, high accuracy implying low error.

accuracy/resolution: The smallest change in magnitude a sensor can detect.

activity: A task that consumes time and resources and whose performance is necessary for a model or simulation to move from one event to the next.

activity-based simulation: A discrete simulation that represents the components of a system as they proceed from activity to activity; for example, a simulation in which a manufactured product moves from station to station in an assembly line.

activity model: A model of the processes that make up the functional activity showing inputs, outputs, controls, and mechanisms through which the processes of the functional activity are or will be conducted.

adaptive systems: A system that is able to adapt its behavior according to changes in its environment or in parts of the system itself.

adjunct tool: Software and/or hardware used to provide part of a simulation environment or to transform and manage data used by or produced by a simulation environment. Differentiated from a model in that a tool does not model anything.

advanced distributed learning: An evolution of distributed learning (distance learning) that emphasizes collaboration on standards-based versions of reusable objects, networks, and learning management systems, that may be delivered synchronously or asynchronously and may include some legacy methods and media.

advanced distributed simulation: A set of disparate models or simulations operating in a common synthetic environment in accordance with the Distributed Interactive Simulation (DIS) standards. The advanced distributed simulation may be composed of three modes of simulation (live, virtual and constructive), which can be seamlessly integrated within a single exercise.

Affine Representation: Coordinate system that is defined by using the location of feature points in an image.

affine transformation: A transformation in which straight lines remain straight and parallel lines parallel. Angles may undergo changes and differential scale changes may be introduced.

agent: A computer system capable of autonomous action to some extent. This includes deciding for itself what it needs to do to satisfy its design objectives, and capable of interacting with other agents (i.e., a 3D character that exhibits human or human like behavior). Also known as a virtual human.

agent-based model: Generates simulated data that can be analyzed inductively. Unlike typical induction, however, the simulated data come from a rigorously specified set of rules rather than direct measurement of the real world.

agent-based modeling: A specific logical model representation intended for replication and use in computer simulation. Agent-based modeling is intended to depict an intrinsically cognitive and social representation that manifest themselves in the actions and characteristics of the agents that are influenced by the actions and characteristics of other real or modeled agents in a social system.

agent-based simulation: Agent-based simulation focuses on the implementation of agents and the sequence of actions and interactions of the agents over periods of time. Agent-based computer simulations are individual-based computational representations extensively related to the theme in complex systems, emergence, Monte Carlo Method, computational sociology, multi-agent systems, and evolutionary programming.

agent-directed simulation: Promoted as a unified and comprehensive framework that extends the narrow view of using agents simply as system or model specification metaphors.

aggregate (unit): A group of entities or a group of other aggregates. The substitution of the word "unit" is used to avoid phrases like "aggregate aggregate."

aggregation: 1. The ability to group entities while preserving the collective effects of entity behavior and interaction while grouped. 2. Process of changing the resolution to represent items in a simulation in less detail.

Air and Space Natural Environment M&S Executive Agent (ASNE MSEA): The ASNE MSEA works to enable Joint and Service M&S customers to represent the air and space natural environment rapidly, thoroughly, and consistently in a manner that promotes cost-effectiveness, ready access, interoperability, re-use, and confidence. The ASNE MSEA is a member of the M&S Foundations Integrated Process Team.

algorithm: A prescribed set of well-defined unambiguous rules or processes for the solution of a problem in a finite number of steps.

algorithm checks: A rigorous verification of the mathematics of an algorithm to ensure freedom from any errors in the expression (e.g., incorrect signs, incorrect variables applied in the equations, derivation errors) and to ensure that the algorithms are consistent with their stated intents.

aliasing. Having jagged edges, as a result of a discrete approach to scan conversion in which each pixel either is replaced with the primitive's color or is left unchanged.

alternate key: A property or characteristic that can be used as a secondary identifier for an entity or entity class.

analysis: The systematic, thoughtful, and rigorous employment of the scientific method to examine a problem, scenario, or issue in order to gain insights into relationships between constituent components, understand underlying principles, or answer a specific set of pre-identified questions.

analytical model: A model consisting of a set of solvable equations; for example, a system of solvable equations that represents the laws of supply and demand in the world market.

analytical modeling: An analytical model is the abstraction of a system based on probability theory. The analytical model represents the description of a formal system consisting of equations used to estimate the performance of the system.

angle of field: A property of a lens. The angle subtended by lines that pass through the center of the lens and locate the diameter of the maximum image area within the specified definition of the lens. Lenses are generally classified according to their angles of coverage, as follows: narrow angle; wide-angle; normal angle; and super-wide angle or ultra-wide angle. Also called angle of coverage; angular field.

animation: 1. Used to experience a simulation in real-time (e.g., training simulations). 2. Graphics play-back and visualization are techniques that allow the analyst to see the M&S behavior through time. This is particularly useful for validating representations of vehicle/unit movement, weapons firings and interactions.

application layer (layer 7): The layer of the Open Systems Interconnection reference model that provides the means for simulation applications to access and use the network's communications resources.

application programming interface: 1. A formalized set of software calls and routines that can be referenced by an application program in order to access supporting network services. 2. Serves as a virtual interface (exchange) between two functions. For example, it specifies how a programmer writing an application accesses the behavior and state of classes and objects. The Windows application programming interface includes code for an assortment of dialog box controls.

architecture: The structure of components in a program or system, their interrelationships, principles, and guidelines governing their design and evolution over time.

area of interest displays: Generating and displaying imagery in the direction in which the user is looking at any given moment.

areal feature: 1. A topographic feature, such as sand, swamp, or vegetation, that extends over an area. It is represented on the published map or chart by a solid or screened color, by a prepared pattern of symbols, or by a delimiting line. 2. (digital mapping) Any area enclosed by a delimiting line that has any unique characteristic (e.g., forest, residential) 3. (raster) A block of grid cells which represent a homogeneous portion of the earth.

areal object: A synthetic environment object that is geometrically anchored to the terrain with a set of at least three points that comes to a closure.

articulated part: A visible part of a simulated entity that is able to move relative to the entity itself.

articulation parameter record: Used to represent the state of the movable parts of an entity.

artificial intelligence:artificial intelligence. Intelligence as exhibited by a man-made, non-natural, or manufactured entity.

aspect ratio: Numerical ratio of picture width to height.

asset: 1. A collection of associated artifacts that together composes a system or subsystem. May exist in two types: resource asset and support asset. 2. A reusable collection of associated artifacts that together composes a system or subsystem. An asset has capability or content useful beyond its original application, has been developed or enhanced to be of sufficient generality and quality to support reuse, has been approved for reuse, has been documented with pertinent metadata, and has been placed into a repository.

associative entity: An entity that inherits its primary key from two or more other entities (those that are associated). An associative entity is used to represent many-to-many relationships.

assumption: A supposition on the current situation or a presupposition on the future course of events, either or both assumed to be true in the absence of positive proof necessary to enable the commander in the process of planning to complete an estimate of the situation and make a decision on the course of action.

astronomical unit: A unit of length equal to 149,600,000 kilometers (adopted 1960) used for measuring distances within the solar system. This distance approximates the mean distance of the Earth from the Sun.

asynchronous transfer mode: A form of packet transmission using fixed-size packets, called cells. Asynchronous transfer mode does not provide error control and flow control mechanisms.

asynchronous transmission:asynchronous transmission. Transmission in which each information character is individually synchronized, usually by the use of start elements and stop elements.

atmosphere: 1. The air surrounding the Earth. 2. The mass of air surrounding the earth and the features embedded within it, including clouds, smoke, and fog. 3. A kind of mission space entity representing the atmosphere.

attached part:attached part. A visible part of a simulated entity that may or may not be present (e.g., a bomb on an aircraft wing station).

attribute: 1. A property or characteristic of one or more entities (e.g., color, weight, sex). 2. A property inherent in an entity or associated with that entity for database purposes. 3. A named characteristic of an object class or object instance.

attribute overloading: The ability of an attribute to carry one of two or more separate facts.

attribute ownership: The property of an instance attribute that gives a joined federate the capability to supply values for that instance attribute to its federation execution.

attributive entity: An entity that has the same primary key as the parent and additional attributes that eliminate the occurrence of repeating groups in the parent.

augmented reality: A type of virtual reality in which synthetic stimuli are registered with and superimposed on real world objects, often used to make information otherwise imperceptible to human senses perceptible.

augmented reality (wearable): With augmented reality, a participant wears a see-through display or views video of the real world with an opaque head mounted display that allows graphics or text to be projected in the real world.

mixed reality: A field of computer research which deals with the combination of real-world and computer-generated data. The merging of real-world and virtual reality to produce new environments where physical and digital objects can co-exist and interact in real time, to include augmented reality.

authoring system: Any development tool suitable for developing a useable computer-based application; for example, Computer Based Training, hypertext markup language code for viewing on the Internet, modeling and simulation applications, computer- or Internet-based tests and surveys.

authoritative data source: A data source whose products have undergone producer data verification, validation, and certification activities.

authoritative representation: Models, algorithms, and data that have been developed or approved by a source which has accurate technical knowledge of the entity or phenomenon to be modeled and its effects.

automated forces:automated forces Computer-generated forces that require little or no human interaction.

automated information system: A combination of computer hardware and computer software, data, or telecommunications that performs functions such as collecting, processing, storing, transmitting, and displaying information. Excluded are computer resources, both hardware and software, that are: physically part of, dedicated to, or essential in real-time mission performance of weapon systems; used for weapon system specialized training, simulation, diagnostic test and maintenance, or calibration; or used for research and development of weapon systems.

autonomous: A battlefield entity that does not require the presence of another battlefield entity in order to conduct its own simulation in the battlefield environment. All Distributed Interactive Simulation (DIS) -compliant battlespace entities are autonomous in that they are responsible for creating their own view of the environment.

avatar: A virtual object used to represent a participant or physical object in a virtual world; the representation, typically visual, may take any form.

azimuth angle: 1. An angle measured clockwise in the horizontal plane between a reference direction and any other line. 2. (astronomy) The angle 180 degrees or less between the plane of the celestial meridian and the vertical plane containing the observed object, reckoned from the direction of the elevated pole. In astronomic work, the azimuth angle is the spherical angle at the zenith in the astronomic triangle which is composed of the pole, the zenith, and the star. In the geodetic work, it is the horizontal angle between the celestial pole and the observed terrestrial object. 3. (surveying) An angle in triangulation or in a traverse through which the computation of azimuth is carried. In a simple traverse, every angle may be an azimuth angle. Sometimes, in a traverse, to avoid carrying azimuths over very short lines, supplementary observations are made over comparatively long lines, the angles between which form azimuth angles. In triangulation, certain angles, because of their size and position in the figure, are selected for use as azimuth angles, and enter into the formation of the azimuth condition, equation (azimuth equation).

B

ballistic munition: Any munition that follows a predetermined ballistic trajectory.

ballistics: The motion, behavior, appearance, or modification of missiles or other vehicles acted upon by propellants, wind, gravity, temperature, or any other modifying substance, condition, or force.

baselining: A configuration management term that implies that the item is placed under formal control so that it cannot be changed without going through a formal review process.

bathymetric model data: Soundings from the Bathymetric Archive Data layer selected to form the Bathymetric Model Data layer. These soundings form the model of the ocean floor for the compilation of Nautical Charts.

bathymetry: The science of determining and interpreting ocean depths and topography.

battlefield view: A battlefield entity incorporates a direct soldier/machine interface that replicates the soldier/machine interface of the actual battlefield entity.

battlespace: Refers both to the physical environment in which the simulated warfare will take place and to the forces that will conduct the simulated warfare. All elements that support the front line forces (e.g., logistics, intelligence) are included in this definition of battlespace.

battlespace database: Database that defines the specific domain of an engagement. It includes the parametric data needed to generate an operating version of the simulated world. When combined with the session database (which provides the scenario and other simulation-specific data), the battlespace can generate an exercise. Battlespace is also used as a shortened notation for "battlespace database".

battlespace entity: A simulation entity that corresponds to actual equipment, supplies, and personnel that can be seen or sensed on a real battlefield.

behavior: For a given object, how attribute value changes affect (or are affected by) the object attribute value changes of the same or other objects.

behavior database entity: Collection of gathered behavior data.

behavioral modeling: Model of a human activity in which individual or group behaviors are derived from the psychological or social aspects of humans. Behavioral models include a diversity of approaches. The most prevalent computational approaches to human behavior modeling are social network models and multi-agent systems.

benchmark: An accepted representation or standard of a process being modeled or simulated against which the results of other models or simulations are compared or judged.

benchmarking: The activity of comparing the results of a model or simulation with an accepted representation of the process being modeled.

best effort service: A communication service in which transmitted data is not acknowledged. Such data typically arrives in order, complete and without errors. However, if an error occurs, nothing is done to correct it (e.g., there is no retransmission).

bilinear interpolation: A method of image re-sampling that derives a new pixel value based on the gray levels of the four nearest neighbors.

bit: The smallest unit of information in the binary system of notation.

black box model: A model whose inputs, outputs, and functional performance are known, but whose internal implementation is unknown or irrelevant. Contrast with: glass box model, white box model.

black box testing: Outputs are determined correct or incorrect based upon inputs; inner workings of the module are ignored.

boundary condition: The values assumed by the variables in a system, model, or simulation when one or more of them is at a limiting value at the edge of the domain of interest. Contrast with: final condition; initial condition.

bounding box: A prism which encloses all the vertices of a given 3D object.

bounding volume: The six-sided, rectangular enclosing space whose width, length and height are aligned with spatial extents of the entity.

broadcast: A transmission model in which a single message is sent to all network destinations, i.e., one-to-all. Broadcast is a special case of multicast. Contrast with: multicast; unicast.

browsing: Opportunity for users to freely examine and peruse through the contents of a database.