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- address:
- A value that identifies a location or is the starting point for computing such a location. For example, a register number, the address of a particular part of storage device, a device address, a network address.
- addressability:
- (1) In computer graphics, the number of addressable points on a device space or in storage. (2) In micrographics, the number of addressable points, within a specified film frame, computed as follows: the number of addressable horizontal points by the number of addressable vertical points; for example, 4000 by 4000.
- addressable point:
- Any point that can be located in a predefined coordinate system.
- addressable track:
- A continuous group of sectors in which each sector can be addressed in a linear manner beginning with sector number 0.
- address administration:
- The assignment of network addresses.
- address format:
- The number and arrangement of elements within an address. For examples, page and offset in a virtual-address system; channel, device, sector, and record in magnetic disk storage.
- addressing exception:
- An exception that occurs when a program calculates an address outside the bounds of the address space available to it.
- address modification:
- Any arithmetic operation, logic operation, or syntactic operation performed on an address.
- address offset:
- A number that must be added to a relative address to determine the address of the storage location to be accessed.
- address part:
- The part of a machine instruction or microinstruction that specifies the address of an operand.
- address register:
- A register that is used to hold an address.
- address space:
- The set of addresses that can be used by a particular program or functional unit. The address space may include virtual addresses.
- address track:
- A track that contains addresses that may be used to locate data on other tracks of the same data medium.
- address translator:
- A functional unit that transforms virtual addresses to real addresses.
- ad impression:
- An occurrence of an advertising banner on a Web page at a user's terminal.
- adjacency:
- In character recognition, a condition in which two consecutively printed characters printed on the same line are separated by less than a specified distance.
- adjacent domains:
- Two domains interconnected by means of equipment located at a single common node or between nodes of two networks.
- adjacent nodes:
- Two nodes connected by a branch.
- adjust text mode:
- A mode that enables a user to reformat text to accommodate specified line length and page sizes.
- administration domain name:
- An attribute that identifies an administrative domain. (Figure 65 - Selected O/R address attributes). (Figure 66 - Examples of O/R addresses).
- administrative domain:
- A domain managed by a single management organization.
- administrative security:
- Administrative measures for computer security. Example measures are operational and accountability procedures, procedures of investigating breaches in security, and reviewing audit trails. Synonymous with procedural security.
- ADP:
- Automatic data processing.
- ADP system:
- Synonym for computer system.
- ADT:
- abstract data type.
- advice taking:
- Learning by being told in which procedural behavior is modified according to the declarative advice of an external knowledge source.
- advisory system:
- An expert system that gives advice rather than dictates to the user.
- affirmation:
- In electronic mail, a transmittal event in which a message transfer agent reports that the message transfer system could deliver any message described in a probe to its immediate recipients.
- affordance:
- In virtual reality, the means of entering a virtual world and making it part of the participant's experience.
- after-image:
- A copy of a block or record after modification.
- afterimage:
- A visual response that temporarily remains after the stimulus causing it has ceased.
- agenda:
- In artificial intelligence, a prioritized list of pending activities.
- aggregate:
- In data representation, a structured collection of components, where the components may have the same or different data structure, and where the data structure of the collection itself may also be a constituent part of a corresponding composite type.
- aggregate value:
- The data value associated with an aggregate.
- aggregation:
- In security, acquisition of sensitive information by collecting and correlating information of lesser sensitivity.
- AI:
- artificial intelligence.
- aiming beam:
- A visible beam generated coaxially with an infrared or an invisible beam in order to aid in positioning.
- aiming circle:
- Synonym for aiming symbol.
- aiming field:
- Synonym for aiming symbol.
- aiming symbol:
- On a screen, a circle or other pattern of light used to indicate the area in which the presence of a lightpen can be detected at a given time. Synonymous with aiming circle, aiming field.
- airborne mouse:
- A type of mouse used in virtual reality applications. Synonymous with flying mouse, 3D mouse, air mouse.
- air mouse:
- Synonym for airborne mouse.
- algebraic language:
- A programming language that permits the construction of statements resembling algebraic expressions. For example, Ada, Fortran, Pascal.
- algebraic manipulation:
- The processing of mathematical expressions without concern for the numeric values of the symbols that represent numbers.
- ALGOL:
- A specific general-purpose, high-level language suitable for communicating algorithms, executing them on different computers, and teaching computer science. The name is derived from ALGOrithmic Language.
- algorithm:
- A finite ordered set of well-defined rules for the solution of a problem.
- algorithmic language:
- An artificial language for expressing algorithms.
- alias:
- (1) An identifier that may be used for a language construct. (2) In networking, each of the alternate names that can designate a network resource. (3) Synonym for alternate name.
- aliasing:
- In computer graphics, unwanted visual effects caused by insufficient sampling resolution or inadequate filtering to completely define the display image; it is most commonly seen as a jagged or stepped edge along the boundary of the object or along a line.
- A-life:
- Abridged term for artificial life.
- alphabet:
- (1) A character set in which the order of its elements has been agreed upon; for example, the 128 ASCII characters. (2) An ordered set of symbols used in a language; for example, the Morse code alphabet, the 128 ASCII characters.
- alphabetic character set:
- A character set that contains letters and may contain special characters, but not digits.
- alphabetic code:
- A code whose application results in an alphabetic code set.
- alphabetic code set:
- A code set whose elements are constructed from an alphabetic character set.
- alphabetic string:
- (1) A string consisting solely of characters from an alphabetic character set. (2) A character string consisting solely of letters and associated special characters from the same alphabet.
- alphabetic word:
- A word that consists of characters from the same alphabetic character set.
- alphanumeric:
- Pertaining to data that consist of both letters and digits, and may contain other characters, such as punctuation marks, or pertaining to processes and functional units that use such data.
- alphanumeric character:
- A character of an alphanumeric character set.
- alphanumeric character set:
- A character set that contains both letters and digits, the space character, and may contain special characters.
- alphanumeric code:
- A code whose application results in an alphanumeric code set.
- alphanumeric code set:
- A code set whose elements are constructed from an alphanumeric character set.
- alphanumeric data:
- Data represented by both letters and digits, the space character, and possibly special characters.
- alphanumeric literal:
- Synonym for string literal.
- alphanumeric word:
- A word that consists of characters from the same alphanumeric character set.
- alternate name:
- (1) An alternate label; for example, a label and one or more alternate names may be used to refer to the same data element or point in a program. Synonymous with alias. (2) In an information resource dictionary, any name by which an entity is known and that may be associated with more than one entity. Synonymous with alias.
- alternate recipient:
- A potential recipient to which a message or probe is to be conveyed if and only if it cannot be conveyed to a preferred recipient. The alternate recipient may be specified either by the originator or by potential recipients.
- alternate track:
- A spare track that is used in place of a normal track in the event that the latter is damaged or inoperable.
- ALU:
- arithmetic and logic unit.
- ambient light:
- Light present in the environment surrounding a vision system, but not supplied by the system.
- amplitude resolution:
- A measure of the accuracy with which a digital system can distinguish between the magnitudes of two samples of a signal. Amplitude resolution is typically expressed as the number of bits necessary to express in binary form the maximum number of possible different signal levels that can be recognized by the system.
- amplitude shift keying (ASK):
- Modulation in which a modulating digital signal varies the amplitude of the output signal among a fixed number of predetermined values.
- analog:
- Pertaining to variable physical quantities or to data presented in a continuous form or to processes and functional units that use such data.
- analog adder:
- Synonym for summer.
- analog computer:
- A computer that accepts, processes, or produces analog data.
- analog data:
- Data represented by a physical quantity that is considered to be continuously variable and whose magnitude is made directly proportional to the data or to a suitable function of the data. Contrast with discrete data.
- analog divider:
- A functional unit whose output analog variable is proportional to the quotient of two input analog variables.
- analog image:
- An image that uses continuous ranges of values; for example, an image that is represented with a continuous range of brightness and hues. Contrast with digital image.
- analog input channel:
- An input path along which analog data flows, possibly including various analog processes such as filtering, amplification, or demultiplexing. Example: in process control, the analog path between the connector and the analog-to-digital converter.
- analog input channel amplifier:
- An amplifier attached to one or more analog input channels, such as one that adapts the analog signal level to the input range of the succeeding analog-to-digital converter.
- analog multiplier:
- A functional unit whose output analog variable is proportional to the product of two input analog variables. This term may also be applied to a device that can perform more than one multiplication; for example, a servo multiplier.
- analog output channel:
- An output path along which analog data flows, possibly including various analog processes such as filtering, amplification, or multiplexing. Example: in process control, the analog path between the analog-to-digital converter and the connector.
- analog output channel amplifier:
- An amplifier attached to one or more analog output channels, such as one that adapts the output signal range of the digital-to-analog converter to the signal level necessary to control the technical process. If there is a common digital-to-analog converter in the subsystem, the amplifier may perform the function of a sample-and-hold device.
- analog representation:
- A representation of the value of a variable by a physical quantity that is considered to be continuously variable, the magnitude of the physical quantity being made directly proportional to the variable or to a suitable function of the variable. Contrast with discrete representation.
- analog signal:
- A signal in which the characteristic quantity representing data may assume, at any instant, any value within a continuous interval. For example, an analog signal may follow continuously the values of another physical quantity representing data.
- analog-to-digital converter (ADC):
- A functional unit that converts data from an analog representation to a digital representation. Synonymous with A/D converter.
- analog variable:
- A continuously variable signal representing either a mathematical variable or a physical quantity.
- analysis:
- The methodical investigation of a problem employing the separation of the problem into smaller related units for further detailed study.
- analyst:
- A person who performs analysis and proposes solutions such as the development of algorithms and procedures.
- analytical attack:
- In computer security, an attempt to break a code or to find a key using analytical means; for example, a statistical analysis of patterns; search for flaws in an encryption algorithm. Contrast with exhaustive attack. Synonymous with cryptanalytical attack.
- analytic learning:
- An advanced form of deductive learning in which abstract or structured knowledge is derived from operational knowledge and from domain knowledge. Synonymous with explanation-based learning.
- anchor:
- (1) A hypermedia node that is the source of a hyperlink. Synonymous with anchor point. (Figure 71 - Difference between anchor and hotspot).
(2) In text processing, to tie a figure or a frame to a page or a paragraph.
- anchor point:
- Synonym for anchor.
- AND:
- A logic operator having the property that if P is a statement and Q is a statement, then the AND of P, Q is true if both the statements are true, false if either statement is false. P AND Q is often represented by P•Q, or by P^Q.
- AND element:
- Synonym for AND gate.
- AND gate:
- A gate that performs the Boolean_operation of conjunction. For Boolean variables assuming values of 0 or 1, an AND gate outputs a value 1 if and only if all the input values are 1; otherwise it outputs a value 0.
- AND-NOT operation:
- Deprecated synonym for exclusion.
- AND operation:
- Synonym for conjunction.
- angle modulation:
- Modulation in which the phase angle or frequency of a sine wave carrier is varied.
- angle-of-view:
- The angle formed between two lines drawn from the most widely separated points in the object plane to the observer.
- animatronic:
- Electronically created and generated and manipulated to appear "alive".
- anisochronous transmission:
- A data transmission process in which there is always an integral number of unit intervals between any two significant instants in the same group; the group may be a block or a character. Between two significant instants located in different groups, there is not always an integral number of unit intervals.
- ANN:
- artificial neural network.
- annotation:
- In a programming language, an added descriptive comment or explanatory note.