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AAT ICAS 1400 ✧ specification of element set structures

document note: this document is part of the Integrated Chronological Applications System (ICAS). Alliance for the Advancement of Technology (AAT) provides ICAS standards documents subject to terms of use described in document AAT ICAS 9010. please refer to other key AAT ICAS standards documents accessible via the AAT ICAS web site at for important information about ICAS.

this document describes principles by which ICAS element sets are structured. AAT ICAS element sets are provided by AAT for general use subject to effective ICAS terms of use. the AAT ICAS element sets are intended to serve as a primary scheme for the development of additional localized sets. the development of ICAS element sets requires a designated grade of ICAS licensing subject to AAT ICAS 9045. please see AAT ICAS 3030 for additional information about namespace and format issues.

ICAS element sets include the use of localization, term, format, and character sets. principles of element set uniformity are structured for purposes of localization, lexicography, formatting, sequencing, and extensibility.


use of system identifiers

ICAS systems should be identified with ICAS system identifiers. traditional systems of calendar and clock should be identified with traditional system identifiers.

elements must also conform with the aaticas namespace structure: the use of an aaticas element must be coherently related to other elements. for example, 'monthtableUniform' may be represented in relation to 'weekGregorian'. yet 'monthtableUniform' is specified for use with 'yeartableUCA' (or 'UCN') rather than 'yeartableGregorian'.

the use of traditional system identifiers is permitted for use with ICAS methods and applications; however uses must not contradict nor misrepresent ICAS standards. the use of traditional scales of calendar and clock should be identified by traditional system identifiers, not ICAS system identifiers. please see AAT ICAS 2026 for additional usage guidelines concerning the representation of mode for traditional scale formats.


structure of ICAS element sets

term sets and other element sets are structured for both canonical and normative use, with specification for both long and short forms. a principle for the designation of symbols for principal and derived units is to provide for a coherent set of symbols that can be used coherently with prefixes for unit multiples and sub-multiples. ICAS elements are structured to possess unique element identifiers subject to specification by AAT ICAS. those ICAS elements subject to sequencing conditions are moreover structured in terms of a designated sequence.

localized elements should be sufficiently distinguishable in relation to existing chronological terms. usage of terms should promote unitary coherence and avoid confusion among different scales of measure. sufficiency of term distinction is relative distinction of terms in use.


scale structure of ICAS elements

ICAS elements are structured with regard to scale and context sensitivity. terms are scale sensitive if their meaning or use is restricted to the use of a particular ICAS or traditional calendar or clock scale. examples of scale-sensitive terms include 'New Calendar', 'Uniform Calendar', 'uniform yeargroup', 'uniform month', 'uniform daygroup', 'Gregorian calendar', 'week', 'am/pm', and so forth. terms are scale insensitive if their meaning or use does not depend on the use of a particular ICAS or traditional scale. Examples of scale-insensitive terms include 'noon', 'midnight', 'morning', 'afternoon', 'evening', and so forth. terms are context sensitive if their meaning is context sensitive to the scale referenced and may possess meanings specific to a particular use. Examples of context sensitive terms include 'month', 'yearend', 'monthend'.


alphanumeric structure of ICAS elements

ICAS elements are structured with regard to alphanumeric sensitivity. certain elements such as uniform months, uniform daygroup, uniform daygroup days, and dial unit terms are structured for alphabetical representation. numeric representation concerns the use of arabic or roman numerals, however roman numerals are in certain cases designated for lexical expression to distinguish among units designated for numerical expression.


sequence structure of ICAS elements

certain ICAS elements are subject to sequencing conditions that may or may not be localization-dependent. insofar as certain ICAS elements are used in terms of sequence, the lexicography of elements should be considered to be subject to a scheme of sequence or order. those sequence elements designated for initial-capital casing should moreover possess an initial capital letter that is unique among the particular localized element set.

as uniform month elements are subject to frequent use as data elements, uniform months should be regarded as subject to a strict scheme of sequence. similarly, uniform daygroup and other calendar elements may also be subject to a scheme of sequence.

as yeargroup terms are typically used to identify historical eras or epochs rather than data sequences, yeargroup term schemes may not be subject to a strict scheme of sequence. however a structure of alphabetical sequence for uniform yeargroup terms can also enhance practicability for certain applications or methods.

for example, term designations for uniform yeargroups might be developed with reference to a meta-data structure selected from taxonomical schemes:

even-numbered yeargroups in terms of a letter character of calendar set A-M

odd-numbered yeargroupss in terms of a letter character of calendar set N-Z

there is no special specification of which 10 characters in a particular calendar set should be used, only that the members of a calendar set be sequenced alphabetically. where integrated however, the use of letters 'i' or 'o' as a 13th set sequence should be designated in terms of a special calendar set order for a particular convention.

there is moreover no special specification of which taxonomical scheme should be used for a particular application. one project or localization might reference a decadeInsect termset, while another project concerned with presenting or organizing a particular domain of natural data might decide to develop uniform termsets in terms of another natural taxonomical scheme.


case structure of ICAS elements

certain ICAS elements are subject to case sensitivity in support of usable design. uniform principles for the design of elements include the application of designated casing schemes to new element long and short form names. for this reason lowercased element names are derived from terms other than the names of persons. however as uniform months are always upper-cased, the designation of proper name long forms corresponding to uniform month short forms is reserved to ICAS users. uniform principles for the expression of ICAS prefixes remain under consideration as provisional specifications [please see 1600-ps03 in AAT ICAS 1600].

at the same time users need to consider that the use of ICAS terms as meta-data in some specialized format applications might be subject to non-normative casing. a data field that is forced uppercased, is forced lowercased, is otherwise case-insensitive, or that is truncated, can affect the representation of data.


format structure of ICAS elements

format structures should be clearly established for a particular context of use, or for accommodating data-interchange. data formats and schemes of metadata are however numerous, and thus ICAS users are responsible for the specification and reference of any formats designated with reference to other types of data that might be subject to disambiguation with regard to format encoding.

thus users should consider the appropriateness of applying a particular format: 'UCN 12006' can be represented appropriately in a timestamp, whereas 'c6' might be appropriately represented as metadata in a filename. in practice, careful structuring or presentation of formats is sometimes necessary to help users to disambiguate particular terms as calendar or numerical terms from similar terms as names.


natural language guidelines

measures of communication or representation for the use of uniform scales of calendar and clock may be established with reference to the applicable use of a designated system of ICAS identifiers and usage guidelines. for example, developers of uniform month tablesets can reference a designated Unicode character set for a designated localization of ICAS.

for a designated natural language, the development of ICAS standards should proceed with reference to a natural language as a common, global, or international form; to anticipate the meaningful communication of uniform scales of calendar and clock across any varieties of standard or established language usage.

as much as is possible and practical with reference to one or more either similar or different natural languages, the development of ICAS standards for the use of uniform scales of calendar and clock shall proceed in anticipation of a system of symbolic representation that can be meaningfully communicated across a larger number of different natural languages.

for purposes related to the administration of ICAS, AAT ICAS shall pursue development of an ICAS English with reference to global or international varieties of English as a natural language.

ICAS users and licensees should anticipate that standard terms, identifiers, and usage conventions are subject to further development, revision, and localization.

top document updated:

system identifiersdatetime
Uniform CalendarUCUCN 12019 S19 Yellow
Inter-Dial ClockIDCzone(UT)t339 tt050
'ICAS in use' can accommodate calendar and clock formatting 'for all people, for all time'.
day of yearD-o-YAD common year day139
Gregorian calendarGG2019 May 19 Sunday
seconds, minutes, hoursSMHUT08:08:14
style legend


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