y
`
`security management information base
`
`1016
`
`segment
`
`security management information base (SMIB) A manage-
`ment information base (MIB) that stores security-relevant ob-
`jects.
`(C/LM) 802.10a-1999, 802.10-1998
`security policy The objectives and mandates for protecting in-
`formation, services, and other resources in a system, and the
`philosophy of protection for meeting those objectives.
`(C/BA) 896.3-1993w
`security service (1) A service, provided by a layer of commu-
`nicating open systems, that ensures adequate security of the
`systems or of data transfers. Note that these security services
`need not be directly requested at the (N)- and (N⫹)-layer
`boundary as is required for an OSI (N)-service.
`(LM/C) 802.10-1992
`(2) The capability of the system to ensure the security of sys-
`tem resources or data transfers. Access controls, authentica-
`tion, data confidentiality, data integrity, and nonrepudiation
`are traditional data communications security services.
`(C/BA) 896.3-1993w
`security system The aggregate assemblage of hardware and as-
`sociated software that includes all components, equipment,
`barriers, etc., necessary for the physical protection of nuclear
`power generating stations against the design basis threat of
`radiological sabotage.
`(PE/NP) 692-1997
`security tag An information unit containing a representation of
`certain security-related information (e.g., a restrictive attri-
`bute bit map).
`(C/LM) 802.10g-1995, 802.10-1998
`security threat A potential violation of security.
`(LM/C) 802.10-1992, 802.10g-1995
`SED Static Electric Discharge; an alternate name for ESD.
`(SPD/PE) C62.47-1992r
`sedimentation potential (electrobiology) The electrokinetic
`potential gradient resulting from unity velocity of a colloidal
`or suspended material forced to move by gravitational or cen-
`trifugal forces through a liquid electrolyte. See also: electro-
`biology.
`(EMB) [47]
`sediment separator (rotating machinery) Any device, used to
`collect foreign material in the lubricating oil. See also: oil
`cup.
`(IA/APP) [90]
`Seebeck coefficient (for homogeneous conductors) (of a cou-
`ple) The limit of the quotient of: the Seebeck electromotive
`force by the temperature difference between the junctions as
`the temperature difference approaches zero: by convention,
`the Seebeck coefficient of a couple is positive if the first-
`named conductor has a positive potential with respect to the
`second conductor at the cold junction. Note: The Seebeck
`coefficient of a couple is the algebraic difference of either the
`relative or absolute Seebeck coefficients of the two conduc-
`tors. See also: thermoelectric device.
`(ED) [46]
`Seebeck
`coefficient,
`absolute
`absolute Seebeck
`See:
`coefficient.
`Seebeck coefficient, relative See: relative Seebeck coefficient.
`Seebeck effect The generation of an electromotive force by a
`temperature difference between the junctions in a circuit com-
`posed of two homogeneous electric conductors of dissimilar
`composition: or, in a nonhomogeneous conductor, the elec-
`tromotive force produced by a temperature gradient in a non-
`homogeneous region. See also: thermoelectric device; ther-
`moelectric effect.
`(ED) [46]
`Seebeck electromotive force The electromotive force resulting
`from the Seebeck effect. See also: thermoelectric device.
`(ED) [46]
`Seed In 10BROAD36, the 23 bits residing in the scrambler shift
`register prior to the transmission of a packet.
`(C/LM) 802.3-1998
`
`seeding See: fault seeding.
`SEE-IN See: Significant Event Evaluation and Information
`Network.
`seek (1) To position the head or access mechanism of a direct-
`access device to a specified location. Synonym: position.
`(C) 610.10-1994w
`(2) An activity that positions a pointer at a specific location
`within a data file.
`(C/MM) 855-1990
`
`(3) (data management) See also: search; search cycle.
`(C) 610.5-1990w
`
`seek key See: search key.
`seek time The time it takes to position the head or access mech-
`anism of a rotating storage device to a specified location.
`Synonym: positioning time. See also: access time; search
`time.
`(C) 610.10-1994w
`segment (1) (A) (data management) (software) One of the
`subsystems or combinations of subsystems that make up an
`overall system; for example, the accounts payable segment of
`a financial system. (B) (data management) (software) In
`storage allocation, a self-contained portion of a computer pro-
`gram that can be executed without maintaining the entire pro-
`gram in main storage. See also: page. (C) (data manage-
`ment) (software) A collection of data that
`is stored or
`transferred as a unit. (D) (software) (data management) In
`path analysis, a sequence of computer program statements
`between two consecutive branch points. (E) (data manage-
`ment) (software) To divide a system, computer program, or
`data file into segments as in (A), (B), or (C). (F) (data man-
`agement) (software) A fixed-length unit of data that contains
`one or more data items. (G) (software) (data management)
`In some databases, the smallest unit of data that can be re-
`trieved or stored. Synonym: database segment. See also: twin
`segment; parent segment; dependent segment; logical seg-
`ment; child segment; physical segment; root segment.
`(C) 610.5-1990, 610.12-1990
`(2) (computer graphics) A logically related collection of dis-
`play elements with their associated attributes such that the
`collection can be manipulated as a unit. (See corresponding
`figure.) Synonym: display group; entity; display segment. See
`also: segment attribute.
`
`Segment 1
`Segment 2
`segment
`
`(C) 610.6-1991w
`(3) The medium connection, including connectors, between
`medium dependent interfaces in a LAN.
`(C/LM) 802.9a-1995w
`(4) The portion of a ringlet between the producer and con-
`sumer along which a packet is sent. The segment traversed
`by a send packet is the send segment, and the segment tra-
`versed by an echo is the echo segment.
`
`(C/MM) 1596-1992
`(5) A specific transmission medium that supports the FAST-
`BUS protocol and to which FASTBUS devices may attach.
`A segment is capable of supporting autonomous operation
`and communicating with other segments via segment inter-
`connects.
`(NID) 960-1993
`(6) The protocol data unit (PDU) of 52 octets transferred
`between peer DQDB Layer entities as the information pay-
`load of a slot. It contains a segment header of 4 octets and a
`segment payload of 48 octets. There are two types of seg-
`ments: Pre-Arbitrated (PA) segments and Queued Arbitrated
`(QA) segments.
`(LM/C) 8802-6-1994
`(7) One or more sections of coaxial cable that form the trans-
`mission medium for a network.
`(C) 610.7-1995
`(8) A portion of a session that is contiguous in simulation time
`and in wall clock (sidereal) time.
`(DIS/C) 1278.3-1996
`(9) On a magnetic drum or disk, one of a series of addressable
`segments within a track or a band on which information is
`stored. See also: cluster; storage element.
`
`(C) 610.10-1994w
`
`

`

`IEEE 100
`
`The Authoritative Dictionary of
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`IEEE Standards Terms
`
`
`Seventh Edition
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`.IEEE
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`Published by
`Standards Information Network
`IEEE Press
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