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- L1 cache:
- Synonym for level-one cache.
- L2 cache:
- Synonym for level-two cache.
- label:
- (1) In organization of data, an
identifier that is attached to a set of data elements. (2) In programming languages, an identifier for a location in a program. A label is frequently used to refer to a statement. In BASIC, a line number can serve as a label. In Fortran, a label, consisting of up to five digits, that precedes a statement, may be used to refer to the statement. In other programming languages, a label is typically an alphanumeric string beginning with an alphabetic character.
- LAN:
- local area network.
- LAN broadcast:
- Sending of a frame that is intended to be accepted by all other data stations identified by a LAN group address.
- LAN broadcast address:
- A LAN group address that identifies a subset of the data stations to receive broadcasts, such as, alerts, system status reports, etc. Synonymous with LAN global address.
- land and groove:
- A trench-like feature on an optical disk, applied before the recording of any data, and used to define the track location.
- landscape:
- The arrangement of text or graphics on a page so that the page is oriented for normal reading when its width exceeds its length. Synonymous with landscape format, horizontal format. (Figure 37 - Landscape and portrait modes)
- landscape format:
- Synonym for landscape.
- LAN gateway:
- A functional unit that connects a local area network to another network using different protocols or where more control is desired than that provided by a simple router. The network may be another local area network, a public data network, or another type of network. (Figure 6 - Interconnecting networks).
- LAN global address:
- Synonym for LAN broadcast address.
- LAN group address:
- An address that identifies a group of data stations on a local area network.
- language:
- (1) A set of symbols, characters, utterances, gestures, conventions, and rules for conveying information. (2) In computer programming, a set of characters, conventions, and rules for constructing expressions and for the interpretation of these expressions.
- language construct:
- A syntactically allowable part of a program that may be formed from one or more lexical tokens in accordance with the rules of a programming language.
- language preprocessor:
- A functional unit that effects preparatory processing of programs. For example, a macrogenerator may function as a language preprocessor of a translator.
- language processor:
- A functional unit for translating and executing programs written in a specified programming language. For example, a LISP machine.
- LAN individual address:
- An address that identifies a particular data station on a local area network.
- LAN multicast:
- Sending of a frame that is intended to be accepted by a group of selected data stations on the same local area network.
- LAN multicast address:
- A LAN group address that identifies a subset of the data stations to receive a multicast.
- LAN server:
- A data station that provides specific services to other data stations on a local area network. For example, a file server, print server, mail server.
- laptop computer:
- A battery-powered portable computer small enough and light enough to be operated on a person's lap.
- laser disk:
- An optical disk, typically 12 inches (30 cm) in diameter. Contrast with compact disk.
- laser printer:
- An electrostatic printer that uses a laser beam for image formation.
- laser scanner:
- A functional unit that moves a spot of laser light across an object and creates an image from the reflection observed.
- last-in-first-out (LIFO):
- A queuing technique in which the next item to be retrieved is the item most recently placed in the queue. (Figure 23 - Stack, queue, and double-ended list).
- latch:
- A circuit that maintains one of its possible stable states until it receives a particular combination of input signals.
- late binding:
- A characteristic of programming languages that perform most bindings during execution, usually to achieve flexibility; for example: dBASE, SmallTalk.
- latency:
- The time interval between the instant at which a call for data is initiated and the instant at which the actual transfer of the data begins. Synonymous with waiting time. (Figure 1 - Access time).
- layer:
- (1) In distributed data processing, a group of capabilities, functions, and protocols considered as a whole, that belongs to a given level in a hierarchical arrangement, of such as features of a given network architecture, and that extends across various data processing systems. (Figure 47 - The Open Systems Interconnection Reference Model).
(2) In a hierarchically organized artificial neural network, a group of artificial neurons whose outputs may connect to neurons in a group toward the output of the network but not to neurons in a group back toward the input of the network. Artificial neurons of the same layer may have connections among them.
- layer-3 switch:
- In the network layer, a high-speed router for forwarding traffic at the same speed, or near the speed of a layer-2 switch, and which cross connects stations or LAN segments.
- layered network:
- An artificial neural network whose artificial neurons are hierarchically organized in layers. A layered network may have a distinct group of source nodes in addition to the layers of artificial neurons.
- layout character:
- Synonym for format effector.
- layout object:
- An element of the specific layout structure of a document. For example, a page, a block.
- LCD:
- liquid-crystal display.
- leader:
- The blank section of at the beginning of a reel of tape.
- leading decision:
- A loop control that is executed before the loop body.
- leading zero:
- In positional notation, a zero in a more significant digit place than the digit place of the most significant nonzero digit of a numeral.
- leaf:
- Synonym for terminal node.
- leapfrog test:
- A check routine that copies itself throughout storage.
- learning:
- (1) The process by which a biological or an automatic system gains knowledge or skills that it may use to improve its performance. (2) The process by which an artificial neural network improves its performance by adjustment of its parameters in response to a succession of input patterns. In general, learning
consists in connection weight adjustments.
- learning algorithm:
- In machine learning, an algorithm that adjusts a set of parameters or a network structure in response to learning. Such algorithms include genetic algorithms, back propagation in artificial neural networks, and credit/blame assignment in the learning-apprentice strategy.
- learning-apprentice strategy:
- Credit/blame assignment that involves observing an expert and using his or her actions to distinguish desirable moves from undesirable ones so as to avoid excessive search, and providing immediate feedback. The learning-apprentice strategy is frequently applied in the semiautomated construction of expert systems.
- learning by analogy:
- A learning strategy that combines inductive learning and deductive learning so that inductions determine the common characteristics of concepts being compared or associated, and deductions derive the features expected of the concept being learned from these characteristics. Learning by analogy requires the ability to recognize the similarity between two problems and to use rules developed in one problem space in order to solve a problem in another problem space. Synonymous with associative learning.
- learning by being told:
- Rote learning in which knowledge is acquired from an external knowledge source without selecting or transforming relevant elements from the information provided. Synonymous with learning from instruction.
- learning by deduction:
- Synonym for deductive learning.
- learning by discovery:
- Unsupervised learning that derives new rules or laws about a domain by describing regularities in observed data. Synonymous with learning from observation.
- learning by induction:
- Synonym for inductive learning.
- learning from examples:
- Inductive learning of concepts by inferring a general concept description from examples and, optionally, from counterexamples of that concept. Learning from noisy or incompletely defined examples is an advanced form of learning from examples. Synonymous with example-based learning, instance-based learning.
- learning from instruction:
- Synonym for learning by being told.
- learning from observation:
- Synonym for learning by discovery.
- learning from solution paths:
- Reinforcement learning that relies on waiting until a complete solution path for a problem has been found, marking every move along the solution path as a positive example, and marking every move leading directly off the solution path as a negative example.
- learning rate:
- In artificial neural networks, a parameter that regulates the magnitude of changes to connection weights during learning. The amount of change of a connection weight is the product of a value given by the learning algorithm and a coefficient which is the learning rate.
- learning strategy:
- A plan for the use of learning techniques prior to their application.
- learning while doing:
- Reinforcement learning that relies not on waiting for a solution path to be found before assigning blame, but on assigning credit and blame while the search for the solution is still on. Learning while doing includes techniques for noting loops and unnecessarily long paths, dead ends, and failures, to progress toward a goal.
- learning without a teacher:
- Synonym for unsupervised learning.
- least privilege:
- In computer security, the principle requiring that each subject be granted the most restrictive set of privileges needed for the performance of authorized tasks. Restriction of privilege limits damage due to accident, error, mistake, or malice.
- least significant bit (LSB):
- In positional notation, a bit position having the smallest weight used.
- least significant digit (LSD):
- In a positional notation, a digit place having the smallest weight used.
- LED:
- light-emitting diode.
- left-adjusted:
- Synonym for left-justified.
- left-aligned:
- Synonym for left-justified.
- left-hand side:
- The set of propositions or statements in the " if " part of an if-then rule.
- left-justify:
- To shift the contents of a register or a field so that the sigificant character at the left-hand end of the data is at a particular position.
- left-justified:
- In text processing, pertaining to text that is aligned to the left margin but need not be aligned to the right margin. Synonyous with flush-left, left-adjusted, left-aligned.
- letter:
- A graphic character that, when appearing alone or combined with others, represents one or more concepts of a written language, or one or more sound elements of a spoken language. Diacritical marks used alone and punctuation marks are not considered to be letters. Synonymous with alphabetic character. (Figure 12 - Character taxonomy).
- letter quality (LQ):
- Pertaining to print quality of text that is suitable for business correspondence.
- level number:
- A reference number that indicates the position of an item in a hierarchical arrangement. Synonymous with rank.
- level of detail (LOD):
- In virtual reality, the amount of detail or complexity that is displayed at any particular time for any particular object. The level of detail for an object is controllable and may be a function of the distance of the object from the observer.
- level-one cache:
- A cache memory built into a processor. Synonymous with primary cache, L1 cache.
- level-two cache:
- A cache memory consisting of static RAM external to the processor. Synonymous with secondary cache, L2 cache.
- lexical element:
- Synonym for lexical token.
- lexical object:
- In a conceptual schema language, a simple linguistic object that expresses an elemental unit of meaning.
- lexical token:
- A string of one or more characters of the alphabet of a programming language that, by convention, represents an elemental unit of meaning. For example, a literal such as "2G5" or an identifier such as "last_name" in Java. Synonymous with lexical element, lexical unit.
- lexical unit:
- Synonym for lexical token.
- LF:
- The line feed character.
- library:
- A collection of related files; for example, a set of inventory control files in stock control.
- library routine:
- A proven routine that is maintained in a program library.
- licensed program:
- A separately priced program and its associated materials that are offered under certain terms and conditions.
- life-cycle phase:
- A specified portion of the system life cycle.
- lifetime:
- That portion of the execution duration during which a language construct exists.
- LIFO:
- last-in-first-out.
- light button:
- Synonym for virtual pushbutton.
- light-emitting diode (LED):
- A semiconductor device that gives off visible or infrared light when activated. (Figure 38 - Light-emitting diode display).
- light-emitting diode display:
- A display device that creates characters by means of a matrix of light-emitting diodes. (Figure 38 - Light-emitting diode display).
- lightpen:
- A light-sensitive pick device that is used by pointing it at the display surface.
- lightpen detection:
- The sensing by a lightpen of light generated by a display element on a display surface. Synonymous with lightpen hit.
- lightpen hit:
- Synonym for lightpen detection.
- light stability:
- In optical character recognition, the resistance to change of the color of the image when exposed to radiant energy.
- limited type:
- In programming, a private type for which only explicitly declared operations or data attributes are available outside a part of a program in which it is contained.
- limiter:
- In analog computing, a functional unit used to prevent an analog variable from exceeding specified values.
- line:
- (1) A physical transmission medium. The line is the portion of a data circuit external to the data circuit-terminating equipment and to the data switching exchange. Synonymous with transmission line. (Figure 18 - Half of a data link).
(2) In text processing, a sequence of characters, usually consisting of words and spaces, that, as determined by some formatting process, are aligned, usually on a baseline; the length of a line is determined by the space available at that point during formatting.
- linear array sensor:
- A vision sensor consisting of a single row of light-sensitive elements.
- linear list:
- A list whose items are not lists.
- linear network:
- A network in which there is a single principal path that includes all nodes of the network such that all other paths are subpaths of this principal path. A linear network is a special case of a tree network. (Figure 43 - Network topologies).
- linear play:
- Playback of a recorded sequence from start to finish without branching.
- linear prediction coding:
- Prediction coding in which the predicted signal samples are linear combinations of the previous samples. The coefficients of the linear combinations are generally obtained by minimizing the mean square error between the input signal and the signal predicted from prior data.
- linear search:
- A search in which a set of data is scanned in a sequential manner. Synonymous with sequential search.
- line code:
- A code that suits the characteristics of a transmission channel. This code may differ from the code or codes used by the sending and receiving data terminal equipments.
- line editor:
- A text editor in which the user must specify lines in order to access elements of text to be edited within a line or within a group of contiguous lines.
- line feed:
- The movement of the print or display position to the corresponding position on the next line.
- line feed character (LF):
- A format effector that causes the print or display position to move to the corresponding position on the next line.
- line printer:
- A printer that prints a line of characters as a unit.
- line spacing:
- The distance between the baselines of successive lines.
- linguistic object:
- In a conceptual schema language, a syntactically allowable construct in a language.
- link:
- (1) A network component used to connect two nodes directly. The link may be unidirectional or bidirectional. (2) To interconnect data objects by establishing pointers or to interconnect portions of one or more programs by providing links; for example, to link object programs by a linkage editor. (3) A part of a program, often a single instruction or address, that passes control and possibly parameters between separate modules of this program.
- linkage:
- In computer security, the purposeful combination of data or information from one data processing system with data or information from another system to derive protected information. Synonymous with fusion.
- linkage editor:
- A program, that, when processing one or more independently translated object modules or load modules, resolves cross-references among these modules, provides links between or among them, establishes relocatable elements, and, if necessary, adjusts addresses, thus creating new load modules. Synonymous with linker.
- linked list:
- A list in which the items may be dispersed in a storage device, but in which each item contains data for locating the next one. Synonymous with chained list.
- link encryption:
- The use of online cryptographic operations on a data link of a data communication system so that all information transmitted over the link is completely encrypted.
- linker:
- Synonym for linkage editor.
- linking loader:
- A program that combines the functional capabilities of a linkage editor and a loader.
- lipreading system:
- A system used for speech recognition, based on patterns of lip movement.
- liquid-crystal display (LCD):
- A display device that uses the change of the optical properties of a liquid crystal when an electric field is applied; for example, passive matrix display device.
- LISP:
- An applicative programming language oriented to list processing, recursion, and character string manipulation and logic; it is widely used for artificial intelligence applications and is based on the lambda calculus of mathematical logic. LISP is the abbreviation for list processor.
- list:
- (1) A finite, ordered set of related items. The items in a list may be lists. (2) To print or otherwise display data that meet specified criteria.
- list-based access control:
- In computer security, access control in which all of one subject's access rights occur in the subject's access control lists.
- list processing:
- A method of processing data in the form of lists. Linked lists are usually used so that the order of the items can be changed without altering their physical locations.
- list processing language:
- A programming language designed to manipulate data expressed in the form of lists or character strings.
- LISt Processor:
- LISP.
- Listserv:
- The name of an electronic mail system that automatically forwards messages to all members of a group when such messages are received by any authorized member of that group.
- literal:
- A lexical token that, from a syntactic point of view, stands for itself; for example: the names JAN, FEB, MAR . . . in the following definition of a data type are literals.
Month_Type is (JAN, FEB, MAR, APR, MAY,
JUN, JUL, AUG, SEP, OCT, NOV, DEC);
Month : Month_Type;
. . . .
Month : = APR;