Abbreviations & Acronyms

Terms & Definitions

D

Data: A representation of facts, concepts, or instructions in a formalized manner suitable for communication, interpretation, or processing by humans or by automatic means. (references (rr), (ss), and (yyy)).

Data Administration (DAdm): The responsibility for definition, organization, supervision, and protection of data within an enterprise or organization. (references (rr) and (zz)).

Data Administrator (DAd): A person or group that ensures the utility of data used within an organization by defining data policies and standards, planning for the efficient use of data, coordinating data structures among organizational components, performing logical database design, and defining data security procedures. See: Data Steward. (references (rr), (ss), and (bbbb)).

Data Architecture: The framework for organizing and defining the interrelationships of data in support of an organization's missions, functions, goals, objectives, and strategies. Data architectures provide the basis for the incremental, ordered design and development of databases based on successively more detailed levels of data modeling. (reference (rr)).

Data Attribute: A characteristic of a unit of data, such as length, value, or method of representation. (references (ss) and (bbbb)).

Data Center: An organization that serves as a conduit between data sources and data customers. The data center may transform these data as necessary to meet the operational requirements, format, security, and data verification, validation, and certification provisions of its sources and supported users.

Data Certification: The determination that data have been verified and validated. Data user certification is the determination by the application sponsor or designated agent that data have been verified and validated as appropriate for the specific M&S usage. Data producer certification is the determination by the data producer that data have been verified and validated against documented standards or criteria. (references (qq) and (p)).

Data Collection: The process of obtaining information that supports a functional activity, or information requirement. (reference (rr)).

Data Dictionary: A specialized type of database containing metadata that is managed by a data dictionary system. A repository of information describing the characteristics of data used to design, monitor, document, protect, and control data in information systems and databases. (references (ss) and (zz)).

Data Dictionary System: An automated system such as an IRDS that can support one or more data dictionaries. A system specifically designed for managing a data dictionary. (reference (bbbb)).

Data Distribution Management: Allows each federate to further refine RTI data distribution by providing filters scoped to particular object instances or particular regions of the simulation environment. (reference (hh)).

Data Element: A basic unit of information having a meaning and subcategories (data items) of distinct units and values (e.g., address). (reference (zz)).

Data Element Standardization: The process of documenting, reviewing, and approving unique names, definitions, characteristics, and representations of data elements according to established procedures and conventions. (reference (ss)).

Data Entity: An object of interest to the enterprise, usually tracked by an automated system. (references (h), (ss), and (aaaa)).

Data Exchange Standard: Formally defined protocols for the format and content of data messages used for interchanging data between networked simulation and/or simulator nodes used to create and operate a distributed, time and space coherent synthetic environment. (reference (nn)).

Data Integrity: In information processing, the condition in which data is accurate, current, consistent, and complete. (reference (rr)).

Data Item: A subunit of descriptive information or value classified under data element. (reference (zz)).

Data Logger: A device that accepts data outputs (e.g., Protocol Data Units (PDUs)) from a simulation or federation and stores them for later replay in the same time sequence as the data were originally received. See: Protocol Data Unit. (references (b) and (y)).

Data Marshalling: The process of gathering data and transforming it into a standard format before it is transmitted over a network so that the data can transcend network boundaries. In order for an object to be moved around a network, it must be converted into a data stream that corresponds with the packet structure of the network transfer protocol. This conversion is known as data marshalling. Data pieces are collected in a message buffer before they are marshaled. When the data is transmitted, the receiving computer converts the marshaled data back into an object. Data marshalling is required when passing the output parameters of a program written in one language as input to a program written in another language. (reference (ttt)).

Data Model: The user's logical view of the data in a database, in contrast to the physically stored data or storage structures. It also includes a description of the organization of data in a manner that reflects the information structure of an enterprise. (references (rr), (aaaa), (ss), and (yyy)).

Data Repository: A specialized database containing information about data, such as meaning, relationships to other data, origin, usage, and format, including the information resources needed by an organization. (reference (h)).

Data Security: The protection of data from accidental or intentional modification or destruction and from accidental or intentional disclosure to unauthorized personnel. (reference (www)).

Data Source: An organization or subject matter expert who, because of either mission or expertise, serves as a data producer.

Data Standardization: The process of documenting, reviewing, and approving unique names, definitions, characteristics and representations of data according to established procedures and conventions. (references (rr) and (ss)).

Data Steward: The person or group that manages the development, approval, and use of data within a specified functional area, ensuring that it can be used to satisfy data requirements throughout the organization. (references (rr) and (ss)).

Data Structure: The logical relationships that exist among units of data and the descriptive features defined for those relationships and data units. A data structure is a definitive and organized way of describing and storing data in a computer so that it can be used efficiently. (reference (iii)).

Data Synchronization: The timing requirements of a data element, or between and/or among data elements. (reference (h)).

Data Validation: The documented assessment of data by subject area experts and its comparison to known values. Data user validation is an assessment as appropriate for use in an intended model. Data producer validation is an assessment within stated criteria and assumptions. (reference (qq)).

Data Value: A value associated with a data element. One of the allowable values of a data element. (references (h) and (zz)).

Data Verification: Data producer verification is the use of techniques and procedures to ensure that data meets constraints defined by data standards and business rules derived from process and data modeling. Data user verification is the use of techniques and procedures to ensure that data meets user specified constraints defined by data standards and business rules derived from process and data modeling, and that data are transformed and formatted properly. (reference (qq)).

Data Verification, Validation, and Certification (VV&C): The process of verifying the internal consistency and correctness of data, validating that it represents real world entities appropriate for its intended purpose or an expected range of purposes, and certifying it as having a specified level of quality or as being appropriate for a specified use, type of use, or range of uses. The process has two perspectives: producer and user process. (reference (qq)).

Database Administration (DBAdM): The activity responsible for the enforcement of the policies and standards established by the data administrator, to include providing technical support for physical database definition, design, implementation, maintenance, integrity, and security; and coordinating with computer operations technicians, system developers, vendors, and users. Database administration is oriented toward technical support for databases and the effective and efficient use of information technology resources. (reference (h)).

Database Administrator (DBAd): A person or group that enforces policy of "how," "where," and "in what manner" data is stored and maintained in each database. Provides information to the Data Administrator (DA) on organizational use of data within the subject database. (reference (zz)).

Database Directory: A database of entries, each of which represents information about a database or a directory of databases. Information often includes the name of a database or directory, ownership, point of contact, access path to the database or directory, and a description of the purpose of database.

Database Management System (DBMS): A system that provides the functionality to support the creation, access, maintenance, and control of databases, and that facilitates the execution of application programs using data from these databases.

Database Systems: A system or software designed to manage a database and run operations on the data requested (reference (iii)).

Datagram: A unit of data that is transferred as a single, non-sequenced, unacknowledged unit. (reference (u)).

Dead Reckoning: A method for the estimation of the position/orientation of an entity based on a previously known position/orientation and estimates of time and motion. Dead reckoning algorithms are used to reduce communications processing within distributed simulations. (references (v), (hh), (b), (ttt), (vvv), and (ddd)).

Decentralized Architecture: Architecture with multiple, specific locations at which the same or familiar transformational or control functions are performed. (reference (c)).

Declaration Management: Allows each federate to designate filters on High Level Architecture (HLA) Run Time Infrastructure (RTI) notifications about the existence of particular types of remote objects, changes to particular object attributes and particular interaction events. (reference (hh)).

Declared Attributes: The set of class attributes of a particular object class that are listed in the Federation Object Model (FOM) as being associated with that object class in the object class hierarchy tree. (reference (w)).

Declared Parameters: The set of parameters of a particular interaction class that are listed in the Federation Object Model (FOM) as being associated with that interaction class in the interaction class hierarchy tree. (reference (w)).

Defense Information Systems Network: Integrated network, centrally managed and configured to provide long-haul information transfer services for all Department of Defense activities. It is an information transfer utility designed to provide dedicated point-to-point, switched voice and data, imagery, and video teleconferencing services. (reference (fff)).

Defense Simulation Internet (DSI): A wide-band telecommunications network operated over commercial lines with connectivity to both military and civilian satellites, allowing users to be linked on a worldwide wide-area network. Note: superseded with Enhanced Internet Protocol Services in the Defense information System Network (DISN). (reference (qq)).

Defense Switched Network: Component of the Defense Communications System that handles Department of Defense voice, data, and video communications. Also called DSN. (reference (fff)).

Degree-of-Freedom: Capability of motion in translation or rotation. There are potentially six degrees of freedom for a rigid body: translation along X, translation along Y, translation along Z; rotation around X, rotation around Y, rotation along Z. (reference (b)).

Department of Defense World Geodetic System (DoD WGS): A unified world datum based on a combination of all available astrogeodetic, gravimetric and satellite tracking observations. Previous World Geodetic Systems were WGS 59, WGS 60, WGS 66 and WGS 72. The current system is WGS 84. The system is revised as new geodetic, gravimetric and satellite data materials change the currently accepted values. (reference (ggg)).

Dependent Variable: A variable whose value is dependent on the values of one or more independent variables. Contrast with: independent variable (references (b) and (y)).

Deployable Virtual Training Environment (DVTE): DVTE is a first person immersive simulation based training system capable of emulating and simulating a wide variety of weapon systems and generating high fidelity, geo-specific 3D terrain databases. DVTE provides small unit echelons opportunity to continuously review, and rehearse Command and Control procedures (fire plans, control measures, key terrain association, etc.) and concepts in a virtual environment. (reference (sss)).

Descriptive Model: A representation or form used to depict the behavior or properties of an existing system or type of system; for example, a scale model or written specification used to convey to potential buyers the physical and performance characteristics of a computer. Contrast with: prescriptive model. (references (b), (c), and (ss)).

Design of Experiments: Formulation of information gathering attempts where variation is present and which may or may not be under the full control of the experimenter. Process consists of 4 steps; 1. Hypothesis generation, 2. Data Collection, 3. Fitting data through some mathematical or statistical process, and 4. Assessing whether model fits hypothesis. (references (iii) and (j)).

Design Validity: Congruence between the Originating Requirements Document (ORD) and the derived requirements. (reference (c)).

Deterministic: Pertaining to a process, model, simulation or variable whose outcome, result, or value does not depend upon chance. Contrast with: stochastic. references (b) and (vvv)).

Deterministic Algorithm: A process that yields a unique and predictable outcome for a given set of inputs. (reference (dd)).

Deterministic Model: A model in which the results are determined through known relationships among the states and events and in which a given input will always produce the same output; for example, a model depicting a known chemical reaction. Contrast with: stochastic model. (references (b) and (y)).

Deterministic Simulation Model: A simulation model that does not contain any probabilistic (i.e. random) components. (reference (aa)).

Deterministic System: A system in which the new state of the system is completely determined by the previous state and by activity. (reference (ee)).

Developmental Agent (DA): DAs develop and provide life-cycle management for software components of an M&S solution. DAs develop and provide life-cycle management for M&S systems, hardware and software components in their respective domains, including assistance with security accreditation and VV&A documentation. (reference (nn)).

Difference Equations: The use of algebra and a spreadsheet to construct a simulation of a continuous system. (reference (kk)).

Digital Elevation Model (DEM): A numerical model of the elevations of points on the earth's surface. Digital records of terrain elevations for ground positions at regularly spaced horizontal intervals. Data are available for some USGS 7.5 minute topographic quadrangles and 1: 250,000 scale maps. (reference (ggg)).

Digital Feature Analysis Data (DFAD): A database consisting of selected natural and cultural planimetric features type classified as point, line or area features as a function of their composition and size. Each feature is assigned a code and further described with limited attribution. The data are stored in polygon format and segregated into 1 degree tiles. Primary applications are radar return, simulation, navigation, targeting and terrain obstruction studies. When combined with DTED, an off-line database is created for use by simulators. (reference (ggg)).

Digital Feature Data: (cultural data) Manmade, natural and landscape features in digital form, including all man-made features on the earth's surface, e.g., lines of communication, built-up areas (cities), transmission lines and landmark structures. (reference (ggg)).

a. (hydrographic data) Data derived from the measurement and description of physical features of the oceans, lakes, rivers and other waters and their adjoining coastal areas (with particular reference to navigational usage) In digital form. (reference (ggg)).

b. (landscape feature data) Data of all natural feature and man's alteration to those features, e.g., lake with dam, agricultural features, etc., in digital form. (reference (ggg)).

c. (natural feature data) Natural features on the Earth's surface which are not man-made, e.g. vegetation, water bodies, desert, etc. In digital form. (reference (ggg)).

Digital Simulation: A simulation that is designed to be executed on a digital computer system.

a. A simulation that is designed to be executed on an analog system but that represents a digital system.

b. A simulation of a digital circuit. Contrast with: analog simulation. (references (b) and (y)).

Digital Terrain Elevation Data (DTED): A uniform matrix of terrain elevation values produced by DMA. Level 2 post spacing is 1 arc second latitudinally. Level 1 post spacing is 3 arc second latitudinally; for both, longitudinal spacing varies with latitude. (reference (ggg)).

Diopter: A unit of measurement of the power of a lens, especially a spectacle type lens. The power in diopters equals the reciprocal of the focal length in meters; thus, a lens whose local length is 20 cm has a power of 5 diopters. (reference (ggg)).

Diplomatic, Intelligence, Military and Economic (DIME): Factors to study various threats and their affect or real-time decision making or inter-agency rapid response generally using analysis of non-kinetic/low attribution solutions. (references (kk) and (jjj)).

Direct Means: Meeting security objectives through the U.S.-led application of military power. (reference (uu)).

Direction cosine: Cosine of angle between any two unit vectors. (reference (l)).

l1 = cosθcosψ

l2 = cosθsinψ

l3 = -sinθ

 

where θ and ψ are the angles between each vector and a reference axis.

DIS Compliant: A simulation that can send or receive PDUs in accordance with IEEE Std 1278.1-1995 and IEEE Std 1278.2-1995. A specific statement must be made regarding the qualifications of each PDU. (reference (ttt)).

DIS Exercise: Consists of one or more interacting simulation applications using DIS compliant Protocol Data Units (PDU). The DIS PDUs issued by all simulation applications participating in the same exercise shall share one identifying number called the exercise identifier. (reference (v)).

Disaggregate: Activity that decomposes an aggregated entity into multiple entities representing its components. (reference (b)).

Disaggregation: The ability to represent the behavior of an aggregated unit in terms of its component entities. If the aggregate representation did not maintain state representations of the individual entities, then the decomposition into the entities can only be notional. (references (t) and (qq)).

Discrete Model: A mathematical or computational model whose output variables take on only discrete values; that is, in changing from one value to another, they do not take on the intermediate values; for example, a model that predicts an organization's inventory levels based on varying shipments and receipts. Contrast with: continuous model. (references (b) and (y)).

Discrete Simulation: A simulation that uses a discrete model where the dependent variables (i.e., state indicators) change discretely at points in time referred to as events. (references (ee), (b) and (y)).

Discrete System: A system for which the state variables change instantaneously at separated points in time referred to as events. Systems changes can occur in other finite quanta, or jumps. (DSMC 1993- 94 Military Research Fellows Report and Joint Pub 1-02.) (references (ee), (dd) and (ddd)).

Distributable: The ability of M&S components that are primarily geographically separated to operate in concert. (reference (nn)).

Distributed Architecture: Architecture in which there are two or more autonomous processors connected by a communications interface and running a distributed operating system. (reference (c)).

Distributed Interactive Simulation (DIS): A time and space coherent synthetic representation of world environments designed for linking the interactive, free4598 play activities of people in operational exercises. The synthetic environment is created through real-time exchange of data units between distributed, computationally autonomous simulation applications in the form of simulations, simulators, and instrumented equipment interconnected through standard computer communicative services. The computational simulation entities may be present in one location or may be distributed geographically. (reference (s)).

Distributed Interactive Simulation (DIS) Compatible: Two or more simulations and/or simulators are DIS compatible if they are DIS compliant and their models and data that send and interpret Protocol Data Units support the realization of a common operational environment among the systems (coherent in time and space). (reference (b)).

Distributed Interactive Simulation (DIS) Network Manager: A specified agency with the responsibility to manage the physical network used for distributed simulation. Responsibilities include: ensuring security of network; scheduling of utilization; establishing network priorities; monitoring execution of scheduled usage; coordinating functional, technical, and user communities' network requirements. (reference (b)).

Distributed Interactive Simulation (DIS) Protocol Data Unit (PDU): A set of data specified in a protocol of a given layer and consisting of protocol control information of that layer, and possibly user data of that layer. (reference (v)).

Distributed Mission Operations Network: A network connecting AF wing simulators, contractor facilities, and DMOC. (reference (sss)).

Distributed Simulation: A networking of geographically dispersed simulators of model components that execute as a single overall model. (reference (jjjj)).

Distributed Virtual Environment: A virtual environment is said to be distributed if it resides on two (or more) networked computers, which share the simulation computational load. (reference (d)).

DoD M&S Executive Agent: A DoD Component designated by USD (AT &L) to coordinate all aspects of DoD M&S for a designated M&S area. These MSEAs are transitioning to M&S Coordination Agents. There are five such MSEA's. Air Force for Air and Space Environment. Navy for Ocean Environment; National Geospatial- Intelligence Agency for Terrain Environment (now under the authority, direction and control of Under Secretary of Defense for intelligence (USD(I)); Defense Intelligence Agency for Threat Forces and Intelligence Processes (now under the authority, direction and control of USD(I)); and assistant to the secretary of Defense for Nuclear and Chemical and Biological Defense Programs (ATSD(NCB)) for Chemical, Biological, Radiation, and Nuclear Defense M&S. (references (ww), (qq), and (dd)).

Domain: The physical or abstract space in which the entities and processes operate. The domain can be land, sea, air, space, undersea, a combination of any of the above, or an abstract domain, such as an n-dimensional mathematics space, or economic or psychological domains. (reference (xxx)).

Dual-Use Technologies: Technologies with both a military and a civilian application.

Dynamic Model: A model of a system in which there is change, such as the occurrence of events over time or the movement of objects through space; for example, a model of a bridge that is subjected to a moving load to determine characteristics of the bridge under changing stress. (references (b) and (y)).

Dynamic Natural Environment: The natural environment is constantly changing as a result of man-made efforts (battlefield smoke) and natural phenomenon (weather). Incorporating dynamic natural environment into real-time simulations provides a more realistic test bed for weapons, equipment, and personnel. (reference (nn)).

Dynamic Simulation Model: Systems whose response to an input is not instantaneously proportional to that input or disturbance and whose behavior can be characterized by either an n-th order differential equation, a transfer function, or a set of n simultaneous first order differential equations. (reference (hhhh)).