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(1) A collection of rules that maps the elements of the first set onto the elements of the second set. The elements of either set may be characters or character strings. Synonymous with coding scheme. (2) In computer programming, a piece of program text expressed in a programming language or in a form produced by an assembler, compiler, or other translator. (3) Synonym for code set (deprecated), program (deprecated). (4) Synonym for encode. (5) In computer security, a set of rules in which code groups are substituted for plaintext elements that are primarily words, phrases, or sentences; for example, the mapping of plaintext onto ciphertext.

code area:
In computer micrographics, that part of a microform that is reserved for retrieval keys.

code breakpoint:
A breakpoint that depends upon execution of a specific instruction. Synonymous with control breakpoint.

code converter:
A data converter that changes the representation of data by using one code in place of another.

coded character:
A character that has been mapped in accordance with a code such as an alphabetic character expressed in 7-bit ASCII.

coded image:
An encoded representation of a display image for storage and processing. For example, the result of run-length encoding of a digitized image.

code division multiple access (CDMA):
Multiple access that depends upon the use of independently coded modulations within a single channel.

code element:
Synonym for code value.

code-element set:
Synonym for code set.

code-extension character:
A control character used to indicate that one or more of the succeeding code values are to be interpreted according to a different code. (Figure 12 - Character taxonomy).

code generator:
A subprogram, often part of a compiler, that transforms all or part of a program from some intermediate language into an object language.

code group:
In a code system, an apparently meaningless sequence of letters, digits, or both, that represents a portion of plaintext.

code-independent data communication:
A mode of data communication that uses a character-oriented protocol that does not depend on the character set or code used by the data source.

code-line index:
In micrographics, a visual index that consists of an optical pattern of clear and opaque bars parallel to the long edge of roll microfilm and located between images.

A person who writes but does not usually design programs.

code review:
A meeting at which code is presented to project personnel, managers, users, customers, or other interested parties for comment or approval.

code set:
The set of values onto which source data is mapped according to a code. Synonymous with code element set.

code system:
Any system of communications in which groups of symbols are used to represent plaintext elements of varying length. Contrast with cryptographic system.

code trace:
Synonym for execution trace.

code-transparent data communication:
A mode of data communication that uses a bit-oriented protocol that does not depend on the bit sequence structure used by the data source.

code value:
The result of applying a code to an element in source data. For example, "CDG" representing Paris Charles-De-Gaulle in the code for three-letter representation of airport names; the hexadecimal number 0041 representing "Latin capital letter A" in ISO/IEC 10646-1. Synonymous with code element.

In computer programming, the process of expressing a program in a programming language.

coding scheme:
Synonym for code.

The multiplier of an expression or variable used to compute a value. Example: In 3150 = 3.15 * 103, the 3.15 is a coefficient and 103 is an expression that defines the base 1000 to yield 3.15*1000 = 3150.

coefficient unit:
A functional unit whose output analog variable is equal to the input analog variable multiplied by a constant.

coexistence model:
A user's logical view of a database that allows different subschemas to exist at the same time.

cognitive modeling:
The modeling of human perception, action, memory, and reasoning in terms of data and information processing.

cognitive science:
An interdisciplinary knowledge field, whose stated objective is to discover the representational and computational capacities of the mind and their structural and functional representation in the brain. Cognitive science deals with the symbol-processing nature of cognition and encompasses disciplines as diverse as psychology, computer science, linguistics, anthropology, philosophy, education, mathematics, engineering, physiology, and neuroscience.

The manner and degree to which the activities of a single module are related to one another. Strong cohesion implies extensive relationships between activities of the module. Kinds of cohesion may be ranked from strong to weak as follows: functional cohesion, informational cohesion, communicational cohesion, temporal cohesion, logical cohesion, coincidental cohesion. Contrast with coupling. Synonymous with module strength.

coincident-current selection:
In an array of magnetic storage cells, the selective switching of one cell in the array by the simultaneous application of two or more currents such that the resultant magnetomotive force exceeds a threshold value only in the selected cell.

coincidental cohesion:
Cohesion in which the activities of a module have no functional relationship to one another.

computer output to laser disk.

cold site:
An alternative facility with at least the equipment necessary to support the installation and operation of a data processing system in the event of a disaster. Synonymous with shell site.

cold standby:
A configuration in which a redundant functional unit is kept idle or performing secondary functions and can be manually brought into service with some delay, should the primary functional unit fail.

cold start:
The start of a database management system without preprocessing of before-images or after-images.

To arrange two or more sets of data into a single set according to a predetermined order.

collating sequence:
The definition of a predefined order for collating.

A device that collates, merges, or matches sets of punched cards or other documents.

collection angle:
Two times the angle measured between a line from a point in a scene to the center of a detector and a line from the same point to the edge of the same detector.

To make a beam of light in which all optical rays are parallel.

(1) A condition that results from concurrent transmissions on the transmission medium. (2) In hashing, the occurrence of the same hash value for two or more different keys. Synonymous with hash clash.

collision detection:
(1) In virtual reality, the process of determining whether the geometric structures of two or more virtual objects within a scene intersect, or whether, based on the current motion of the virtual objects, the geometries of the virtual objects would intersect. A typical use of collision detection is to determine when or how the avatar is interacting with the virtual objects in the scene by detecting collision between the space conceptually occupied by the avatar in the scene and that of other virtual objects in the scene. (2) In data communications, the detection of the concurrent transmission of two or more signals whose interference prevents reliable reception.

collision enforcement:
In a CSMA/CD network, the transmission of a jam signal by a data station after it has detected a collision, to ensure that all other data stations become aware of the collision.

collision resolution:
In hashing, the process of applying further calculations or other means to resolve a collision.

In optics, the spectral appearance of the image dependent upon the spectral reflectance of the image, the spectral response of the observer, and the spectral composition of incident light. See also color value.

color map:
A set of color values used to translate pixel values into actual colors to be displayed.

color palette:
A set of colors that can be displayed on the display surface at one time. A color palette can be a standard set used for all images or a set that can be customized for each image.

color resolution:
A measure of the ability to distinguish between two color values. Typically, color resolution is expressed by the number of bits necessary to express in binary form the maximum number of possible different color values.

color scanner:
A scanner that converts images to a digitized format and is able to interpret color.

color space:
All the colors that can be represented by a specific color scheme. The color scheme is typically based on red, blue, green, cyan, magenta, yellow, black, and white.

color temperature:
A precise measure of the hue of a given source of light stated as the temperature to which a black body would have to be heated in order to display the same color. Color temperature is expressed in degrees Kelvin.

color value:
The characterization of a color, in terms of hue, saturation, and luminance. In many displays, color is generated by mixing pure colors of various luminances and thus color values are frequently also represented by three numbers corresponding to three pure-color value magnitudes.

One of two or more vertical arrangements of characters, expressions, or lines positioned side by side on a page or screen, or other object such as a card column.

computer-output microfilm.

In a disk drive, an assembly of access arms that moves as a unit.

A given number of different elements selected from a set without regard to the order in which the selected elements are arranged.

combinational circuit:
A logic circuit whose output values, at any given instant, depend only upon the input values at that instant. Contrast with sequential circuit.

combined station:
In high-level data link control, a data station capable of performing the role of a primary station or of a secondary station.

comic-strip oriented image:
In micrographics, an image appearing on roll microfilm in such a manner that the top edge of the image is parallel to the long edge of the film.

(1) An order for an action to take place. (2) A control signal. (3) In a conceptual schema language, the order or trigger for an action or permissible action to take place. (4) Loosely, a mathematical or logic operator.

command condition:
In a conceptual schema language, the precondition, including synchronization aspects, that must be met before a permissible action may take place.

command key:
In text processing, a key that causes a machine function to be performed; for example, a cursor key.

command language:
A set of procedural operators with a related syntax, used to indicate the functions to be performed by an operating system, for example: job control language. Synonymous with control language.

command statement:
In a conceptual schema language, a linguistic object that expresses a command.

A language construct exclusively used to include text that has no intended effect on the execution of the program; for example: an explanation to a human reader; data for an automatic documentation system. Synonymous with remark.

commitment, concurrency, and recovery (CCR):
An application service element that controls operations performed by two or more application processes on shared data to ensure that the operations are performed either completely or not at all.

common coupling:
Synonym for common-environment coupling.

common-environment coupling:
Coupling in which modules access common data. Synonymous with common coupling.

common field:
A field that can be accessed by two or more independent routines.

Common Gateway Interface (CGI):
A standardized interface for the communication of parameters between hyperdocuments and applications. CGI is standardized by the Internet Engineering Task Force (IETF).

common management information service (CMIS):
An application service element that provides a generic mechanism for exchanging information and commands, for the purpose of systems management, in a centralized or decentralized management environment.

common mode rejection:
The capability of a differential amplifier to suppress the effects of the common mode voltage.

common mode voltage:
In a differential amplifier, that unwanted part of the voltage, between each input connection point and ground, that is added to the voltage of each original signal.

common name:
In electronic mail, an attribute or identifier of a user or distribution list relative to the entity denoted by another attribute, for example: title or position within an organization, e.g., "postmaster", "administrator", "director of marketing". A common name or a personal name is required in an O/R address. (Figure 65 - Selected O/R address attributes).

communication adapter:
A hardware feature that allows a functional unit to be attached to transmission facilities.

communicational cohesion:
Cohesion in which the activities of a module use the same input data or contribute to producing the same output data.

communications security:
Computer security applied to data communications.

communication theory:
The mathematical discipline dealing with the probabilistic features of the transmission of messages in the presence of noise and any other disturbances. These probabilistic measures are part of a general statistical theory that is commonly called information theory. Contrast with information theory.

Synonym for pack.

compact disc:

compact disk:

A measure that describes the disbursement of pixels within a region with respect to the center of that region. Compactness is often expressed by a fraction in the range from 0 to 1. A circle is the most compact region; a line is the least compact. Circular objects have the maximum value of 1 and very elongated objects have a compactness approaching 0.

A functional unit that compares two items and indicates the results of comparison. Example: a digital system that compares two bit patterns; an analog computer that compares two analog variables; a signal processor that compares two pulse patterns.

To examine two items to discover their relative magnitudes, their relative positions in an order or in a sequence, or other characteristics.

In security, a nonhierarchical designation applied to sensitive information in one or more categories to denote special handling and access control restrictions. Contrast with security category, security classification.

A division of data into isolated blocks for the purpose of reducing risk. For example: the isolation of the operating system, application software, and files from one another in a storage device in order to provide protection against unauthorized or concurrent access, the separation of files by project to facilitate strict need-to-know discipline.

The capability of a functional unit to meet the requirements of a specified interface without appreciable modification.

competitive learning:
In artificial neural networks, learning in which artificial neurons compete for the right to respond to a given subset of input patterns. The response of a artificial neuron to an input pattern tends to inhibit other artificial neurons.

The process or the result of compiling.

compilation duration:
The amount of time needed to compile a program.

compilation time:
(1) Any instant at which compilation takes place. (2) Deprecated synonym for compilation duration.

compilation unit:
All or part of a program expressed in a high-level language and sufficiently complete to be compiled. Contrast with source module.

To translate all or part of a program expressed in a high-level language into a program expressed in an intermediate language, an assembly language, or a machine language.

An operating technique in which there are no stops between the compiling, linking, loading, and execution of a program.

compiled knowledge:
Knowledge that has been translated into a form that can be immediately or more efficiently processed by a computer than with the noncompiled form.

compile phase:
The logical subdivision of a run that includes the execution of a compiler.

A translator that can compile.

compiler code:
Code expressed in a form that can be recognized and processed by a compiler.

compiler compiler:
Synonym for compiler generator.

compiler directive:
A language construct for controlling the compilation of a program.

compiler generator:
A translator or interpreter used to specify and construct all or part of a compiler. Synonymous with compiler compiler, metacompiler.

compiler specification language:
A specification language used to develop compilers.

compile time:
Synonym for compilation time.

A number that is derived from a given number by subtracting it from a specified number; for example, in a fixed-radix notation, the specified number is typically a power of the radix or one less than a given power of the radix. A negative of a number is often represented by its complement.

complementary operation:
A Boolean operation whose result is the negation of the result of another Boolean operation on the same operands; for example, disjunction is the complementary operation of nondisjunction. (Figure 4 - Table of Boolean operations).

complementary operator:
The logic operator whose result is the NOT of a given logic operator.

complement base:
In fixed-radix notation, the specified number whose digital representation contains the digits from which the corresponding digits of the given number are subtracted in obtaining a complement of the given number.

In programming, pertaining to the task state of a task that is finished and all events dependent on that task have been resolved. (Figure 58 - State transition diagram).

complete generalization:
A concept generalization that describes all positive examples of a given conceptual class and may include negative examples.

complex-instruction-set computer (CISC):
A computer with a very expansive and robust instruction set such as one that includes machine-level instructions to support floating-point arithmetic or matrix operations and that may incorporate several types of addressing modes and varying length of instruction word.

complex instruction set computer processor:
Synonym for CISC processor.

complex number:
A number consisting of an ordered pair of real numbers, expressible in the form a + bi, where: a and b are the real numbers and i² = -1.

composite object:
A hyperobject that consisting of two or more hyperobjects; for example: a menu and a dialog box used for the entry of a character string. (Figure 69 - Examples of object types).

composite type:
A data type that has a data structure composed of the data structures of one or more data types and that has its own set of permissible operations. The operations of a composite type may manipulate its occurrences as a unit or may manipulate portions of these occurrences. For example, a complex number is a composite type composed of two real numbers plus an extended set of operations.

composite video signal:
A single signal created by combining picture content with the components for vertical and horizontal synchronization and for vertical and horizontal blanking.

compound statement:
A statement that contains one or more statements, so delimited as to be the syntactic equivalent of a simple statement.

To reduce the quantity of data by encoding it to take advantage of redundancy in that data, or removing insignificant data. For example, using variable-length codes for encoding text, or run-length encoding of a graphic image. Contrast with pack.

COM printer:
A page printer that produces on photographic film a microimage of each page. Synonymous with computer output microfilm printer.

A violation of computer security whereby programs or data may have been modified, destroyed, or made available to unauthorized entities. (Figure 57 - Levels of security risks).

compromising emanations:
In computer security, signals that are unintentionally emitted and that, if intercepted and analyzed, may reveal sensitive information being processed or transmitted; for example, acoustic emanations, electromagnetic emanations.

computer security.

compute mode:
The mode of an analog computer during which the solution is in progress. Synonymous with operate mode.

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