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- table:
- An arrangement of data in which each item may be identified by means of arguments or keys.
- table lookup:
- A procedure for obtaining the value corresponding to an argument from a table of values.
- tablet:
- A special flat surface with a mechanism for indicating positions thereon, normally used as a locator.
- tabulator:
- A device that reads data from a data medium such as punched cards or punched tape and produces lists, tables, or totals.
- tactile feedback device:
- A device for creating tactile renderings of virtual objects.
- tactile glove:
- The combination of a pneumatic glove and a data glove.
- tag:
- In hypermedia, a language element in a markup language used for structuring data, text, or objects; for example: start-tags and end-tags.
- tailgate:
- To gain unauthorized physical access by following an authorized person through a controlled door or, the electronic equivalent for access to a computer or data.
- tandem:
- Pertaining to a configuration of multiple devices that operate in a sequential manner and in which each device except the last provides one or more input values to the next; for example, a daisy chain.
- tandem data circuit:
- A data circuit that contains more than two data-circuit terminating equipments in a series.
- tape drive:
- Synonym for magnetic tape drive.
- tape frame:
- Synonym for tape row.
- tape punch:
- A punch that automatically produces a punch tape, a record of data in the form of hole patterns.
- tape row:
- A group of binary characters recorded or sensed in parallel on a line perpendicular to the reference edge of a magnetic tape. Synonymous with tape frame.
- tape transport:
- Synonym for magnetic tape drive.
- tape unit:
- Synonym for magnetic tape unit.
- target language:
- A language in which a translator expresses its results.
- target machine:
- (1) The computer on which a program is intended to be executed. (2) A computer that is being emulated by another computer. Contrast with host machine.
- target program:
- The translated version of a source program.
- task:
- In programming languages, a module that can be executed concurrently with other modules either on a multiprocessor or interleaved on one processor. The distinction between a task and a module from the point of view of execution control is not always precise.
- task entry:
- A place in a task that provides an interface for a calling module.
- task state:
- One of the conditions in which a task can be during its lifetime.
- task synchronization:
- The means by which tasks coordinate their activities in time or the process of such coordination; for example, semaphore, monitor, rendezvous.
- taxonomy formation:
- The construction of a concept classification scheme by means of disjunctive classes of clustered concepts. The goal of taxonomy formation is to achieve maximal simplicity and minimal overlap of distinctive characteristics. Contrast with conceptual clustering and concept formation.
- TCP:
- A connection-oriented protocol designed to provide
a communications protocol used in the Internet. TCP provides a reliable host-to-host protocol between hosts in packet-switched communications networks and in interconnected systems of such networks. TCP corresponds approximatively to transport layer protocols within the OSI reference model. TCP is the abbreviation for Transmission Control Protocol.
- TCP/IP:
- Two interrelated protocols that are part of the Internet Protocol suite. TCP operates in the transport layer and breaks data into packets and uses IP to route them between and into networks to produce an end-to-end capability. TCP/IP is the abbreviation for Transmission Control
Protocol/Internet Protocol.
- TCU:
- trunk coupling unit.
- TDM:
- time division multiplexing.
- TDMA:
- time division multiple access.
- technical process:
- In process control, a set of operations performed by equipment in which physical variables are monitored or controlled; for example: distillation and condensation in a refinery, autopiloting and automatic landing in an aircraft.
- telecommute:
- To work at home and to use a workstation to send or receive information to or from the office.
- teleconferencing:
- Interactive communication among participants at different locations, using telecommunication facilities. Teleconferencing includes conference calls and video conferencing with still or moving images. (Figure 60 - Teleconferencing).
- telecopier:
- Synonym for facsimile machine.
- telecopy:
- Synonym for fax.
- tele-existence:
- The human experience of seeing through the eyes of a machine and using natural gestures to direct the machine in the physical world.
- telefax:
- Synonym for fax.
- telemaintenance:
- Synonym for remote maintenance.
- telepresence:
- A psychological experience that creates the impression of being immersed in a remote virtual world.
- telerobotics:
- The remote control of robots being monitored through the use of telepresence.
- teletex:
- An enhanced version of telex that provides both upper and lowercase transmission at higher speeds than telex.
- teletext:
- A broadcasting service that provides selectable text material such as news, weather reports, and advertisements, directly to a subscriber's television set. The subscriber must have a special decoder to receive teletext signals.
- telex:
- An electronic mail service that provides communications among subscribers.
- telnet:
- A virtual-terminal protocol that is used for remote terminal connection service and that allows a terminal at one site to interact with systems at other sites as if that terminal were directly connected to computers at those sites. There is also a specific protocol, called Telnet, that is defined for use with TCP/IP.
- Telnet:
- Name of a specific telnet, using TCP/IP.
- template:
- (1) A reference pattern that is compared with the whole or part of an entity to be recognized. Templates are used in character recognition, in target detection, and in speech recognition. (2) An image or a part of an image that is used to compare with or to generate other images.
- template matching:
- Pattern matching using a template.
- temporal cohesion:
- Cohesion in which the activities of a module are all required at a particular time; for example, a module that contains all of the initializations of a program.
- temporal vision:
- Vision in which data are used to derive a description of changes in visual events over time.
- temporary storage:
- In programming, storage locations reserved for intermediate results.
- tens complement:
- The radix complement in the decimal system.
- term:
- A linguistic construct in a conceptual schema language that refers to an entity.
- terminal:
- A functional unit in a system or communication network at which data may be entered or retrieved.
- terminal node:
- In a hierarchical network, a node that has no subordinate node. Synonymous with leaf.
- terminate and stay resident (TSR):
- A program that remains in memory, after it is executed, ready for reactivation when required.
- terminated:
- Pertaining to the task state of a task that is completed, all events dependent on that task have been resolved and its activation record being released. (Figure 58 - State transition diagram).
- termination test:
- In a loop control, the test in which a TRUE condition indicates that the iteration should halt; for example: in Pascal, the loop-control variable for a termination test is preceded by an "until" clause.
- ternary:
- (1) Characterized by a selection, choice, or condition that has three possible different values or states. (2) Of a fixed-radix notation, having a radix of three.
- ternary incremental representation:
- Incremental representation in which the value of an increment is rounded to one of three values, plus or minus one quantum or zero.
- tessellate:
- To subdivide a shape into simpler shapes; for example, to represent the area of a polygon by a set of triangles.
- test and maintenance program:
- A program designed to test a functional unit primarily for the purpose of maintenance or verification.
- test instruction:
- An instruction that checks the condition of data and sets status or overflow flag bits for a subsequent jump instruction. In some instances, test and branch are considered two operations within a single instruction.
- test language:
- A problem-oriented language that provides the means for testing components of hardware or software; for example: ATLAS, ATOLL, DETOL, DMAD.
- test plan:
- A plan that establishes detailed requirements, criteria, general methods, responsibilities, and general planning for test and evaluation of a system. Synonymous with system test and evaluation plan.
- texel:
- The smallest element of an image used to describe the texture of a surface. The complete description of a surface region requires the 3-dimensional definition of the shape of the surface, a lighting model, and a description of the texels. Synonymous with texture element.
- text:
- (1) Data in the form of characters, symbols, words, phrases, paragraphs, sentences, tables, or other character arrangements, intended to convey a meaning, and whose interpretation is essentially based upon the reader's knowledge of some natural language or artificial language; for example, a business letter printed on paper or displayed on a screen. (2) In data communications, a sequence of characters treated as an entity, if preceded by one start-of-text character and terminated by one end-of-text character, respectively.
- text area:
- The area of a single page or screen in which text or other graphic elements usually appear.
- text editing:
- Using a text processor to prepare or modify text, such as making additions or deletions, rearranging the text, or reformatting. Synonymous with editing.
- text editor:
- Software that enables a user to create and revise text.
- text-formatting language:
- A problem-oriented language designed to indicate the manner in which text should be formatted; for example: HTML, nroff.
- text processing:
- Data processing operations on text, such as entering, text editing, sorting, merging, retrieving, storing, displaying, or printing. Synonymous with word processing.
- text processor:
- A software package or a device with associated software that enables a user to perform text processing. Synonymous with word processor.
- text-to-speech conversion:
- The conversion of text to speech output.
- text-to-speech synthesis system:
- Synonym for text-to-speech synthesizer.
- text-to-speech synthesizer:
- A speech synthesizer that converts text to phonetic symbols, and then to artificial speech. Synonymous with text-to-speech synthesis system.
- text transmission:
- Electronic transfer of text from one point to another over a network.
- texture element:
- Synonym for texel.
- texture mapping:
- A rendering technique for giving a three-dimensional object a specified appearance by mapping the two-dimensional representation of the textures of its modeled surfaces onto its displayed surfaces.
- texture simulation:
- The simulation of solid objects by tactile simulation such that the user can recognize the texture of the objects.
- thematic role:
- The set of functions that an entity may perform during the execution of a script. Thematic roles may be filled by actor entities such as an agent, a co-agent, a beneficiary, or a patient such as a waitress, a customer, or a cashier.
- thermal printer:
- A nonimpact printer in which the characters or images are produced by applying hot elements to heat-sensitive paper directly or by melting ink from a ribbon onto plain paper.
- thermal vision:
- The process of understanding a scene based on its temperature variations.
- thermal wax printer:
- Synonym for thermal wax-transfer printer.
- thermal wax-transfer printer:
- A nonimpact printer that uses heat to melt colored wax onto the output medium to create an image. Synonymous with thermal wax printer.
- thickening:
- In computer graphics, a morphological operation that operates on a component of an image to replace spurious or unwanted pixel values with those of the component.
- thimble printer:
- An impact printer in which the type slugs are mounted at the ends of spring fingers that are attached to a central hub and forming a thimble shape.
- thinning:
- In computer graphics, a morphological operation that operates on the background of a component of an image to replace the pixel values of spurious or unwanted pixels with the pixel values of the background; for example: to reduce pixels at an edge to a line of single-pixel thickness while preserving the full length of the line. Spurious pixels in the background are usually those that have the same pixel value as those of the
component of the image.
- third-generation language (3GL):
- A high-level language that has a high ratio of machine instructions to each of its simple statements and that raises the programmer's level of abstraction to focusing attention on the problem to be solved instead of on an intimate knowledge about how a particular computer works; for example: Ada, BASIC, C++, Java, Pascal.
- thread:
- (1) A process within another process that uses the resources of the latter process. (2) In electronic mail, a sequence of messages that contain closely related information and that can be easily isolated from other messages.
- threat:
- A potential violation of computer security. (Figure 57 - Levels of security risks).
- threat analysis:
- An examination of actions and events that might adversely affect a data processing system.
- three-address instruction:
- An instruction that contains three address parts; for example, an instruction to add the contents of storage locations A and B, and place the result in location C.
- three-dimensional analysis:
- Visual analysis using an algorithm that develops a three-dimensional model of an object or of a part and matches this model with one of a collection of stored models.
- three-dimensional animation:
- A computer-generated animation in which the virtual objects can be viewed from a variety of angles. Synonymous with 3-D computer animation, 3-D animation.
- three-dimensional visualization:
- Synonym for virtual reality realization.
- three-input adder:
- Synonym for full adder.
- threshold:
- (1) A logic operator having the property that if P is a statement, Q is a statement, R is a statement, then the threshold of P, Q, R is true if at least N statements are true, false if less than N statements are true, where N is a specified nonnegative integer called the threshold condition. (2) The threshold condition.
- threshold function:
- A two-valued switching function of one or more not necessarily Boolean arguments that takes the value of one if a specified mathematical function of the arguments exceeds a given threshold value, and zero otherwise; for example, the threshold function
f(a1 ,..., an) = 0 if g < T
f(a1 ,..., an) = 1 if g > T
with g = W1a1 + ... +
Wnan
where: W1 ,..., Wn are positive weights for the real arguments a1 , ..., an; and T is the threshold.
- threshold gate:
- A gate that performs a threshold operation. A threshold gate outputs a value 1 if a specified function of the input variables exceeds a given threshold value; otherwise it outputs a value 0.
- thresholding:
- An image-segmentation technique in which pixels which have attribute values above a specific limit are assigned to one region and those below it are assigned to another region.
- threshold operation:
- An operation that evaluates the threshold function of its operands.
- throughput:
- A measure of the amount of work performed by a data processing system over a given period of time; for example, number of jobs per day.
- thumbnail:
- A miniature graphical representation of a document or of an image.
- thumbwheel:
- A locator or a pointing device that employs a wheel rotatable about its axis to provide a scalar value. A pair of thumbwheels can be used for two-dimensional locations: one thumbwheel provides the position in the vertical direction, while the other provides the position in the horizontal direction.
- ticket:
- In computer security, a representation of one or more access rights that a processor has to an object.
- tile:
- (1) A pixel map that is replicated in the x and y dimensions to fill a region. (2) A window produced by tiling.
- tiling:
- The division of a display space into two or more nonoverlapping windows. Contrast with window cascading, cascaded windows.
- time bomb:
- A logic bomb to be activated at a predetermined time.
- time coordinate system:
- A set of values that defines a time scale and the context for a time base.
- time division multiple access (TDMA):
- A multiple access technique in which a separate time slot is allocated to each data station to access the shared resource.
- time division multiplexing (TDM):
- Multiplexing in which several independent signals are allocated separate periodic time slots for transmission over a single transmission medium.
- time-of-day clock:
- A clock that maintains the time of day and the calendar date. Synonymous with TOD clock, clock calendar.
- time-out:
- An event designed to occur at the conclusion of a predetermined elapsed time. A time-out can be prevented by sending an appropriate signal; a time-out can be canceled by the receipt of an appropriate time-out cancellation signal.
- timer:
- A register whose contents are changed at regular intervals in such a manner as to measure time intervals. Synonymous with clock register.
- time scale:
- A number of time units per second.
- time scale factor:
- A number used as a multiplier to transform the real time of the problem into computer time.
- time server:
- The server maintaining and distributing the correct date and time over a computer network. There is usually a special time-distribution protocol.
- time sharing:
- An operating mode of a data processing system that provides for the interleaving in time of two or more processes in one processor.
- time slicing:
- An operating mode in which two or more processes are assigned quanta of time in the same processor.
- time slot (TS):
- Any cyclic time interval that can be recognized and defined uniquely.
- time unit:
- The basic unit of measure for time in a time coordinate system.
- timing recovery:
- The derivation of a cyclic timing signal from a received digital signal, based on the periodicity of the time slots.
- TOD clock:
- Synonym for time-of-day clock.
- token:
- In a local area network, a specified group of bits serving as a symbol of authority passed successively from one data station to another to indicate the station temporarily in control of the transmission medium. All information is conveyed by frames. Some frames contain a token and no user data, others contain user data and no token.
- token-bus network:
- A bus network in which a token passing protocol is used.
- token passing procedure:
- Synonym for token passing protocol.
- token passing protocol:
- In a local area network using a token, the set of rules that governs how a data station acquires, uses, and transfers the token. Synonymous with token passing procedure.
- token-ring network:
- A ring network that allows unidirectional data transmission between data stations, by a token passing protocol, such that the transmitted data return to the originating station.
- toner:
- A powered pigment that is used in certain types of copiers and printers.
- toner cartridge:
- A disposal or refillable container holding the toner used in printing. Some printer engines pack expendables, such as toner and the photosensitive drum in a single cartridge.
- toolpath:
- The path followed by a tool in a numerically controlled part production.
- top-down:
- Pertaining to a method or procedure that starts at the highest level of abstraction and proceeds towards the lowest level.
- top-level domain name:
- A domain name identifying the highest hierarchical level in the geographical or organizational structure of the addressing system in the Internet. In the Internet, the top-level domain name is either the two-letter ISO Country Code for the country, or an English abbreviation such as "com", "edu", "gov", "mil", "net", or "org".
- total correctness:
- Correctness proving indicating that a program's output assertions follow logically from its input assertions and processing steps, and that, in addition, the program terminates under all specified input conditions. Contrast with partial
correctness.
- total immersion:
- The immersion in which no clue of actual reality is perceived.
- totally connected network:
- A nonlayered network in which each artificial neuron is connected to all the others, or a layered network in which each artificial neuron in a layer is connected to all neurons in the adjacent forward layer. Synonymous with fully connected network.