Technology terms starting with D

1,369 terms

Deviation Criteria Limits established beyond which a Program Manager may not trade-off cost, schedule, or performance without authorization from the milestone decision…
deviation ratio In a frequency modulation system, the ratio of the maximum frequency deviation of the carrier to the maximum modulating frequency of the system under…
device A whiz-bang hardware gizmo (like a disk or tape drive or a modem or a joystick or a mouse) attached to your computer, that the "operating system" tries to…
device certificate In cryptography, a public key certificate or an attribute certificate, issued by a device manufacturer, tying the identity of the device to its attributes.
device credentials Authentication information provided from a device to gain access to the enterprise network. [Exchange 2003]
device driver Software that enables hardware or devices (such as a printer, mouse, or keyboard) to work with your computer.
device password A passcode that a user enters on a mobile device that supports the Exchange ActiveSync protocol.
Devolution of Command Minimal essential operational capability to perform C2 provided in an orderly and timely fashion to a duly authorized successor.
Dew Moisture in the air that condenses on solid surfaces when the air is saturated with water vapor.
DEW/D Directed Energy Weapon/Discrimination.
DEWG, O Directed Energy Weapon Ground, Orbital
DEWL Directed Energy Weapon, Laser (thermal or impulse).
DEWP On a buoy report, the dewpoint temperature taken at the same height as the air temperature measurement.
DF 2 Deuterium Fluoride.
DF-KBS Data Fusion Knowledge Based System.
DFAR Defense Federal Acquisition Regulation
DFARS Defense Federal Acquisition Regulation Supplement. 80
DFAS Defense Financing and Accounting Service.
DFS Distributed File System. A Windows file management system that allows data scattered across multiple servers to be treated as a single group.
DFS (Distributed File System) DFS allows administrators to group shared folders located on different servers by transparently connecting them to one or more DFS namespaces.
DFS (Distributed Files System) A Distributed Files System is a type of mountable networked file system.
DFSK Abbreviation for double-frequency shift keying.
DG OBSOLETE. Defense Guidance. See Defense Planning Guidance.
DGA Director General of Armaments (France).
DGP Defense Group on Proliferation.
DHCP dynamic host configuration protocol
dHTML Abbreviation for dynamic Hypertext Markup Language. A form of HTML used to create Web-page content that, as perceived by the viewer, appears to change…
DI durability index.
Di Group A basic group of Pulse Code Modulation (PCM) channels assembled by Time Division Multiplex. In the United States it usually consists of 24 channels at 1.
DIA Defense Intelligence Agency.
DIAC Defense Intelligence Analysis Center.
diacritics A mark that is added to a letter to change a word's pronunciation or to distinguish between similar words, such as an accent mark or the German umlaut.
diad Synonym dibit.
diagnostic program A program used to investigate the cause or the nature of conditions or problems within specified elements of a system. 2.
dial around Pertaining to long-distance services that require consumers to dial a long-distance provider's access code (or a "10-10" number) before dialing a…
dial back Synonym call back.
Dial by Name A feature that enables a caller to enter a person's name using the keys on a telephone. [Exchange 2007]
dial mode Operation of data circuit-terminating equipment (DCE) so that circuitry, such as data terminal equipment (DTE), associated with call origination is…
dial plan A grouping of telephony users with some specific properties, such as unique telephone extension numbers, that allow the Private Branch eXchange (PBX) to…
dial pulse A dc pulse produced by an end instrument that interrupts a steady current at a sequence and rate determined by the selected digit and the operating…
dial pulsing Pulsing in which a direct-current pulse train is produced by interrupting a steady signal according to a fixed or formatted code for each digit and at a…
dial service assistance (DSA) A network-provided service feature, associated with the switching center equipment, in which services, such as directory assistance, call interception…
dial signaling Signaling in which dual tone multifrequency (DTMF) signals or pulse trains are transmitted to a switching center.
dial switching equipment Switching equipment actuated by electrical impulses generated by a dial or key pulsing arrangement. [47 CFR Pt.36-A]
dial through A technique, applicable to access circuits, that permits an outgoing routine call to be dialed by the PBX user after the PBX attendant has established the…
dial tone A tone employed in a dial telephone system to indicate to the calling party that the equipment is ready to receive dial or tone pulses.
dial-pulse period One complete cycle of a dial pulse, consisting of fall time, break interval, rise time, and make interval. [T1.409-1996]
dial-pulse signaling A method of transmitting a telephone address over a direct-current path. The dc current is interrupted at the transmitting end in a defined pattern…
dial-tone delay The time between the instant of going off-hook and the instant of receiving a dial tone.
dial-up A service feature in which a user initiates service on a previously arranged trunk or transfers, without human intervention, from an active trunk to a…
dialed digits Untranslated address information collected/received from the originating line/trunk. [T1.667-1999]
dialing In a communications system, using a device that generates signals for selecting and establishing connections.
dialog box A box that appears when an application needs additional information to complete a task.
dialup A connection type, usually a port, that is not on a local area network and must be accessed by modem and telephone lines.
DIAM Defense Intelligence Agency Manual
Diameter The length of a straight line that extends from one edge of a tumor or other object, through its center and to the opposite edge.
diametral index of cooperation Synonym index of cooperation.
diazo microfilm A type of non-archival quality film processed by exposure to ammonia and used as a medium for use copies of master microforms See also microfilm and…
dibit A group of two bits. Note: The four possible states for a dibit are 00, 01, 10, and 11. Synonym diad.
DICE Digital Integrated Combat Evaluator.
dichroic filter An optical filter that reflects one or more optical bands or wavelengths and transmits others, while maintaining a nearly zero coefficient of absorption…
dichroic mirror A mirror used to reflect light selectively according to its wavelength.
dictionary A defined list of values referenced by a property.
dictionary arrangement A single alphabetic filing arrangement in which all types of entries (names, subjects, titles, etc.
dictionary attack A method of guessing a user's password or PIN by trying every word in the dictionary until successful. [Exchange 2007]
Dictionary/Thesaurus Within the context of search, a dictionary supports linguistic processing of content and queries against a list of words/terms/phrases in order to improve…
DID defense in depth - multiple layers of security to provide added protection to IT resources
dielectric A substance in which an electric field may be maintained with zero or near-zero power dissipation, i.e., the electrical conductivity is zero or near zero.
dielectric filter See interference filter.
dielectric lens In the radio regime, a lens made of dielectric material that refracts radio waves in the same manner that an optical lens refracts light waves.
dielectric strength Of an insulating material, the maximum electric field strength that it can withstand intrinsically without breaking down, i.e.
dielectric waveguide A waveguide that consists of a dielectric material surrounded by another dielectric material, such as air, glass, or plastic, with a lower refractive…
difference frame Synonym delta frame.
Difference Score A value returned by a biometric algorithm that indicates the degree of difference between a biometric sample and a reference.
differencing virtual hard disk A virtual hard disk that stores the changes to an associated parent virtual hard disk for the purpose of keeping the parent intact.
Differential An electrical signal characteristic which transmits information through a current loop to minimize signal noise and allow the SCSI bus to operate reliably…
differential encoding Encoding in which signal significant conditions represent binary data, such as "0" and "1", and are represented as changes to succeeding values rather…
Differential Global Positioning System (DGPS) A positioning procedure that uses two receivers, a rover at an unknown location and a base station at a known, fixed location.
differential Manchester encoding Encoding in which (a) data and clock signals are combined to form a single self-synchronizing data stream, (b) one of the two bits, i.e.
differential mode attenuation In an optical fiber, the variation in attenuation among the propagating modes.
differential mode delay In an optical fiber, the variation in propagation delay that occurs because of the different group velocities of different modes.
differential mode interference Interference that causes a change in potential of one side of a signal transmission path relative to the other side. 2.
differential modulation Modulation in which the choice of the significant condition for any signal element is dependent on the significant condition for the previous signal…
differential phase-shift keying (DPSK) Phase-shift keying that is used for digital transmission in which the phase of the carrier is discretely varied (a) in relation to the phase of the…
Differential Power Analysis (DPA) An analysis of the variations of the electrical power consumption of a cryptographic module, using advanced statistical methods and/or other techniques…
differential pulse-code modulation (DPCM) Pulse-code modulation in which an analog signal is sampled and the difference between the actual value of each sample and its predicted value, derived…
differential quantum efficiency In an optical source or detector, the slope of the curve relating output quanta to input quanta.
differentially coherent phase-shift keying See coherent differential phase-shift keying.
differentially encoded baseband Synonym non-return-to-zero mark.
differentiating network A network, or circuit, that produces an output waveform that is the time derivative of the input waveform.
Diffraction The spreading out of electromagnetic radiation as it leaves an aperture. The angle of spread, which cannot be eliminated by focusing, is proportional to…
diffraction grating An array of fine, parallel, equally spaced grooves ("rulings") on a reflecting or transparent substrate, which grooves result in diffractive and mutual…
diffraction limited In optics, pertaining to a light beam in which the far-field beam divergence is equal to that predicted by diffraction theory. 2.
diffraction region In radio propagation, a region that is in the geometric shadow of an electromagnetic source, but into which propagation nonetheless takes place by virtue…
diffuse reflection Reflection from a rough or irregular surface which does not maintain the integrity of the incident wavefront.
diffusion The spontaneous movement of molecules from a region of higher concentration to a region of lower concentration.
digerati Knowledgeable individuals at the forefront of Internet development and implementation. [Bahorsky] Note: Derived from the word "literati."
digest To cut DNA molecules with one or more restriction endonucleases.
Digest Access authentication Authentication method that transmits user names and passwords in a secure format.
Digest Access Protocol (DAP) A lightweight authentication protocol for parties involved in communications that are based on Hypertext Transfer Protocol (HTTP) or Simple Authentication…