The process of obtaining data from a storage device or system.
Data in the form of continuously variable physical quantities. [C]
The use of computer graphics (or sometimes cinematography) to synthesize drawings or other objects so as to depict motion.
A database containing data values and other information retained over a period of time and represented as an accurate reflection of the contents at a specified time. [C]
An organized and managed collection of information (in any form) that is protected to ensure its integrity as an authoritative source for the information stored in it.
The capability of a device to perform functions that are normally associated with human intelligence, such as reasoning, learning, and self-improvement. [C]
Asynchronous transfer mode.
The transmission of information in irregular sections, with the time interval of each transmission varying and each section being identified by a start and stop signal. [C]
The process by which a prospective computer user's identity is verified by a card, token, or biometric device before system access is allowed. [C]
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--> APPENDIX B Glossary A Access. The process of obtaining data from a storage device or system. Analog data. Data in the form of continuously variable physical quantities. [C] Animation. The use of computer graphics (or sometimes cinematography) to synthesize drawings or other objects so as to depict motion. Archival database. A database containing data values and other information retained over a period of time and represented as an accurate reflection of the contents at a specified time. [C] Archive. An organized and managed collection of information (in any form) that is protected to ensure its integrity as an authoritative source for the information stored in it. Artificial intelligence. The capability of a device to perform functions that are normally associated with human intelligence, such as reasoning, learning, and self-improvement. [C] Asynchronous transfer mode. The transmission of information in irregular sections, with the time interval of each transmission varying and each section being identified by a start and stop signal. [C] Authentication. The process by which a prospective computer user's identity is verified by a card, token, or biometric device before system access is allowed. [C] NOTE: The sources of the definitions appearing in this glossary are indicated by the symbols in boldface square brackets. These sources are spelled out in detail below. Where no source is shown, the definition was crafted explicitly for this glossary by the committee.
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--> B Backbone. (1) A set of nodes and their interconnecting links providing the primary data path across a network .... A backbone may be configured as a bus or as a ring; (2) in a wide area network, a high-speed link to which nodes or data switching exchanges are connected. [IBM] Bookmark method. Refers to a system designed to leave a marker in an application or presentation to which the system will return when the program is next executed. Bridge. A functional unit that interconnects two local area networks that use the same logical link control protocol but may use different access control protocols. [IBM] Broadband transmission. In communications, pertaining to transmission facilities whose bandwidth is greater than that available on voice grade circuits and therefore capable of high-speed data transmission. [L&S] Browser. A program used to scan and search electronic files. Bulletin board. A set of files, stored on a computer, that may be accessed by any user with a terminal and that is controlled by a systems operator, who organizes the files into topical areas. Files are uploaded and downloaded by users, and most bulletin boards allow users to exchange electronic mail. Computer suppliers often maintain a bulletin board to allow users to have access to information system updates and to report on problems encountered. [D] C Cache. (1) A special-purpose buffer storage, smaller and faster than main storage, used to hold a copy of instructions and data obtained from main storage and likely to be needed next by the processor; (2) a buffer storage that contains frequently accessed instructions and data; it is used to reduce access time; (3) an optional part of the directory database in network nodes where frequently used directory information may be stored to speed directory searches. [IBM] Client/server. A network system designed to share substantial resources that cannot be provided on every user's machine. The requesting program (client) sends a request to a program at another site (server) and awaits a response. Compilation. (1) With respect to computer programs, the result of the implementation of a compiler program used to make a high-language program operable in a computer; (2) the result of aggregating several documents or files. [C] Cyberspace. The invisible, intangible world of electronic information and processes stored at multiple interconnected sites, with controlled access and manifold possibilities for interaction. D Data. Scientific or technical measurements, values calculated therefrom, and observations or facts that can be represented by numbers, tables, graphs, models, text, or symbols and that are used as a basis for reasoning or further calculation.[C]
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--> Data collection. The process of identifying and accumulating data and/or data sets pertaining to a common subject, application, or theme. [C] Data exchange. (1) The transfer of data between or among more than one computer program or system; (2) for people or organizations, the sharing of data between or among people and/or organizations. Data integrity. The property/quality of a collection of data being complete, consistent, and accurate. [C] Data management/data administration. (1) The function of controlling the acquisition, analysis, storage, retrieval, and distribution of data; (2) in an operating system, the programs that provide access to data, perform or monitor organization and storage of data, and control input/output devices. [C] Data processing. The systematic performance of operations on data, such as handling, merging, sorting, and computing. [C] Data transfer. Transmission, copying, or movement of digitized data from one place to another, such as from database to database or computer to computer. [C]. Data validation. A process used to determine whether data are accurate, complete, and/or reasonable. [C] Database (also data set). A collection of interrelated data, often with controlled redundancy, organized according to a schema to serve one or more applications. The data are stored so that they can often be used by different programs with little or no restructuring or reorganization of the data. A systematic protocol is used to add new data or modify and retrieve existing data. [C] Database management. The activity associated with organizing, storing, and providing access to a computerized database. It usually includes responsibility for ensuring the integrity of the database. [C] DECnet. A family of software products supporting the general interconnection of computer systems of Digital Equipment Corporation; also used to refer to a network that uses this software. Decryption. The process that reverses encryption, turning a file into plain text. Derogation. An act partly repealing something, or lessening it in value, force, authority, rank, honor, or the like. Desktop publishing. The local production of high-quality, camera-ready copy by an individual or individuals by means of sophisticated word-processing, graphics, and other software packages and laser printers. Digital signature. A means by which the recipient of a message can validate that it came from the person who claims to have sent it. A sender can create a signature for a message and encrypt it with his or her private key. The enciphered signature can be decrypted only by the sender's corresponding public key known to the recipient. A signature encrypted by any other private key, corresponding to another individual or source, cannot be decrypted by the same public key.
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--> E Electronic mail (also e-mail). A method of sending messages from a user on one computer to the computer of another user. In its simplest form, electronic mail on a local area network operates by storing all mail messages on files on one machine designated as the post office. Mail does not move around; users access the post office when they want to ''collect" their mail and read it. On larger systems, post offices are interconnected and can exchange mail, so that users on different LANs can also communicate. [IBM] Electronic publishing. (1) Submission of text, graphics, and images in electronic form to a publisher who will work directly on these files with various computer-assisted techniques to ready the material for publication; (2) submission of articles, data tables, graphs, etc., to an electronic network where they may be browsed, annotated, critiqued, or downloaded. Encryption. A process that transforms data/information, using a key or keyed process, so that only the recipient who has the same key or appropriate keyed process can read it. Traditional encryption uses secret keys that must be exchanged separately among senders and recipients. The same key used for encryption of a message is used for decryption. See also public-key encryption. E-print archive. A collective file of full-text electronic journals, available on the Internet, selections from which can be readily downloaded by individual scientists. Evaluated data. Data that have been subjected to evaluation and can be regarded as scientifically correct within the limits specified. Evaluation. The process of establishing the accuracy and integrity of measured data. Evaluation involves examination and appraisal of the data presented, assessment of experimental techniques and associated errors, consistency checks for allowed values and units, comparison with other experimental or theoretical values, reanalysis and recalculation of derived quantities as required, selection of best values, and assignment of probable error or reliability. [C] Experimental science. One founded on tests, acts, or operations carried out under controlled conditions and intended to discover something unknown or to test a principle or hypothesis. Extraction. The permanent or temporary transfer of all or a substantial part of the contents of a database to another medium by any means or in any form. [EC] F Full and open exchange of data. Occurs when data and information are made available with as few restrictions as possible, on a nondiscriminatory basis, for no more than the cost of reproduction and distribution. Functional dependence. In databases, an indication of the interrelationships of attributes in a relation. Attribute A of a relation R is functionally dependent on attribute B of relation R if, at every instant of time, each value of B has no more than one value of A associated with it. [L&S]
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--> G Gigabyte. 109 bytes, or 8 x 109 bits. H Home page. A file on the Internet that contains information provided by the sponsor of the home page and links to other files (or processes) of the sponsor or to other locations on the Internet. Hyperlink. The text, number, symbol, or code providing linkage to related items in an electronic file or a network of electronic files. Hypermedia. A system of presenting information in discrete units, or nodes, that are connected by links. The information may be presented using a variety of media such as text, graphics, audio, video, animation, image, or executable documentation. [IBM] Hypertext. Text coded with internal cross-references allowing users to link to other related material posted on the network. [C] I Image. A visually interpretable representation of objects, text, or graphics as displayed, plotted, or printed, that is not semantically coded. Information. Data that have become meaningful as a result of collection, processing, organization, and interpretation, in light of some hypothesis. Informatics (especially in continental Europe). The study of the quantitative aspects of information in any form, including patterns of language use, the production, dissemination, and use of recorded information, and the quantitative aspects of science as a discipline or economic activity. [E] Interactive information system. In computing, a system allowing continuous dialog or two-way communication between a user and the computer. [L&S] Internet. A worldwide network of semiautonomous networks that share a common protocol for internetwork communications and a common form of naming of user and server nodes. Intranet. A dedicated computer network (either a local-or wide-area network) within a corporation or other private institution intended to serve its own needs for data exchange, electronic mail, bulletin boards, etc. with reliability, performance, and security beyond that provided by the public Internet. K Knowbot. An information robot, a sophisticated browser program for scanning networks of files and employing more elaborate detection schemes than simple Boolean filters. Knowledge. An organized body of information that represents a description and understanding of concepts, properties, and relationships as viewed by an authoritative community capable of using it. L LaTeX, TeX. Proprietary word-processing programs especially designed for technical writing. Link. A physical or logical connection between two data items or records.
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--> List server. A mechanism that provides a flow of "issued" information to a routing list maintained by the system. M Megabyte. 106 bytes, or 8 x 106 bits. Metadata. Data about data; consists of descriptors of data in a database to provide systematic information for users, application programs, and database management software. Metadata may be manipulated and searched and may themselves be organized in a database. [C] Mirror site. A proxy server acting as a cache containing duplicated data from a central database so as to facilitate more economic and reliable access by local users. Moore's Law. Computer power (speed) will double every 18 months, for an effective reduction in price by half. Multicasting. The transmission of data from one place to many specific ones, as opposed to broadcasting (which transmits everywhere within a range). An example is the transmission of sound and video over the Internet. [D] Multimedia. Any system that combines computer sound and video; may incorporate an interactive facility. N Natural sciences. Branches of science such as biology, physics, and chemistry that deal with objectively measurable objects or processes observable in nature, as distinguished from the abstract sciences such as mathematics or philosophy. Navigation. Following a path within a file or among files to locate desired information. Near real time. Approximate simultaneity in time; without delay, compression, or expansion in the time variable. Neural network. A system of multiple parallel structures, containing a highly interconnected set of simple elements, exploiting aspects of their collective behavior and operating according to a strict, deterministic set of rules for proceeding from one step to the next. Normalize. To reduce data, data structure, or relations among data to a standard form. In the case of numeric data, normalization may involve presenting a data value in terms of its relation to a reference value, e.g., strength at test temperature as a percent of strength at room temperature. O Object-oriented database. A database of objects (entities including data, queues, data structures, procedures, modules, etc.) using the principles of object-oriented programming and the concept of inheritance of methods by new classes of objects. Observational science. A science founded on observation rather than experimentation.
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--> On-line. Pertaining to an interactive process by which a user and host computer converse. Overlay. (1) The superposition of two graphical representations for purposes of comparison; (2) one of several segments of a computer program that, during execution, occupy the same area of main [or virtual] storage, one segment at a time. [C] P Packet. In data communication, a sequence of binary digits, including data and control signals, that is transmitted and switched as a composite whole. The data, control signals, and possibly error control information are arranged in a specific format. [C] Parallel communication. A form of communication that simultaneously transmits on multiple communication paths controlled as a unit. Portability. Capability for transporting of data or programs between computers or computer systems without any required modification thereof. [C] PostScript. A proprietary (Adobe Systems) page definition language used in desktop publishing and capable of handling full text, mathematics, and graphics. Primary data see raw data Privatization. Transfer from government management and control to management and control by a private company or other nongovernmental organization. Protocol. In a computer system, a formalized set of conventions, including coding, prescribed responses to received signals and/or coded messages, wiring patterns, etc., necessary to establish and maintain communication between two devices or systems. Public good. A product or service typically provided by government that is nondepletable and produces benefits from which others cannot be excluded and which cannot easily be constrained only to those who pay. Public-key encryption. A method of encryption/decryption in which the enciphering and deciphering keys are different and not computable from each other. A person wishing to receive a secret message can publicly distribute the enciphering key, which, when used by the originator of a message, produces an enciphered message that only the secret deciphering key kept by the recipient can decipher. The first and still most widely used public-key algorithm is the RSA algorithm; the public key is derived from the product of two very large prime numbers, and the strength of protection derives from the size of the prime numbers and the resulting computational difficulty in decomposing the product in those primes. R Raw data. Data as originally recorded and that have not been combined, modified, interpreted, or adjusted in any way. Real time. In computing, pertaining to operations that are performed in conjunc-
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--> tion with some external process or user and that are required to meet the time constraints imposed by that process or user, e.g., control of an airplane guidance system or an on-line information service. [L&S] Relational database. A database composed of flat files, each embodying different facets of information about the data, organized by linkages representing one or more relations; the resulting data structure allows the efficient use of many types of data during queries and can be manipulated with great flexibility using a formal relational algebra to derive standard (normalized) forms and to establish equivalencies. Remote access. Capability for communicating with a data processing facility through a data link, usually at a different geographical location. Remote sensing. Gathering and recording of data through a system of one or several sensors capable of obtaining data from afar and transmitting the values to a central computer or other display, recording, or storage device. Retrieval. The location and transfer of selected data or information from a source (long-time memory or another information system) to local computer memory for subsequent processing, display, or downloading to another device. Router. A computer that determines the path of network traffic flow. The path selection is made from several paths based on information obtained from specific protocols, algorithms that attempt to identify the shortest or best path, and other criteria such as metrics or protocolrspecific destination addresses. [IBM] S Search engine. A device or program for scanning a file to match data patterns for purposes of retrieval. Secondary user. A user outside the community by or for which the collection of data was initiated. Serial communication. Transmission of a sequence of signals on a single communication path. Server. A computer on a network that performs functions (e.g., computation, storage, and retrieval) for other computers, terminals, and peripheral devices on the network. Shareware. Software distributed publicly by individuals who have developed a useful program and wish to share it informally (as contrasted to commercial marketing) with others. [adapted from C] Spectral data. Data measured for specific wavelengths of radiation related to the phenomenon being observed. The data may be a continuous function of wavelength value or may indicate only values at discrete wavelengths. Sui generis. Of its own kind; unique. T Terabyte. 1012 bytes, or 8 x 1012 bits.
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--> U User friendly. Characteristic of a system that inexperienced or untrained users feel comfortable working on, and find helpful and not intimidating. Generally, use of such a system does not depend heavily on knowing or remembering procedural details; rather, the system provides hints, guidance, and choices among alternatives at every stage of the interaction. Validated data. Data values or data sets that have been shown to be generated according to standard test methods and practices or other measures of quality, reliability, and precision. [C] Verified data. Data that have been shown to be accurately transcribed or transformed from other representations. Virtual reality. A computer-generated simulation of reality (or imagined reality) with which users can interact using specialized peripherals such as data gloves and head-mounted computer graphic displays. [L&S] W Workstation. (1) A term traditionally used to describe a high-end, high-performance assembly of equipment, including extensive computer graphics capability, as an interactive console for performing a specialized function such as computer-aided design, computer animation, or complex data analysis. Typically, the workstation includes enough computing power and data storage capacity to operate free-standing from any other computer, although workstations are often networked to larger systems for data archives, communication with other workstations, etc. As the technology of personal computers has improved, they have taken on functions previously handled on workstations. (2) Any assembly of computer equipment designed to support the full range of work of an individual. World Wide Web. A tool, based on the hypertext system, for the organization and representation of on-line information available over the Internet. To access the Web, a browser such as Netscape or Mosaic is required. The user must know the address of the home page of the institution whose information is to be accessed. The WWW provides the simplest means of navigating the Internet, giving access to text, images, sound, and video. [D] Sources of Definitions [C] J.H. Westbrook and W. Grattidge, eds. (1991), "A Glossary of Terms Relating to Data, Data Capture, Data Manipulation, and Databases," CODATA Bulletin 23, Nos. I & 2, 196 pp. [D] T. Dodd (1995), Computing: The Technology of Information, Oxford University Press, 160 pp. [E] G.L. Tring, ed. (1994), Encyclopedia of Applied Physics, VCH Publishers. [EC] Directive of the European Parliament and of the Council of the European Union on the Legal Protection of Databases (1996), 96/9/E.C., March 11. [IBM] G. McDaniel, ed. (1994), IBM Dictionary of Computing, McGraw-Hill, 758 pp. [L&S] D. Longley and M. Shain, eds. (1986), Dictionary of Information Technology, 2nd ed., Oxford University Press, 382 pp.