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AAT ICAS 2021 ✧ NC usage guidelines

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 normative AAT ICAS usage guidelines for the New Calendar (NC) system. please refer to AAT ICAS 2020 for additional important usage guidelines, and other AAT ICAS standards for New Calendar specifications and element sets.


New Calendar usage guidelines

New Calendar terms and expressions should be used to represent uses of NC scales, methods, and applications. short form terms should only be used if the long form terms are already established.


table 2021.1 ✧ long and short forms of New Calendar terms

short formlong form
NCNew Calendar era
preMiumpre-megalennial scale of New Calendar
preTiumpre-teralennial scale of New Calendar
NDNNew Calendar era Day Notation
preMium-DNpre-megalennial scale Day Notation


normative scale values

the figurative expression of negative-numbered years as in 'years before' or 'years ago' can be posited in relation to New Calendar scales. however normative expressions of New Calendar years should only be expressed in terms of positive year scales coherent to the New Calendar system (AAT ICAS 1100). for example estimates for creation of the universe correspond to pre-teralennial Gium 0980 to 0990 (about 10 to 20 gigalennia before present); and estimates for development of life on planet Earth correspond to pre-teralennial Gium 0996 (about 3-4 gigalennia before present). similarly, figurative expressions of negative-numbered days as in 'days before' or 'days ago' can be posited in terms of day notation scales. however normative expressions of day notation numbers should be designated in terms of a coherent positive scale or pre-scale.


normative format orders

usage conventions for the order of expression of values and scale identifiers are numerous. indeed, natural language expression of information about scalar values can be determined by a complex array of stylistic and practical factors. users should thus reference good or best practices for data-interchange. ISO 8601 specifies conventions for representing numerical dates and times for purposes of accommodating interchange of formatted data.

interchange of information can occur when the expression of information is expanded, truncated, re-arranged, re-localized, re-sourced, or re-scaled. improper interchange practices can however result in miscommunication or inaccurate information.

a principle of format uniformity can enhance the usability of formatted expressions for dates and times, especially for purposes related to data interchange. date and time expressions ordered in terms of largest to smallest units offer more practical methods for more types of information interchange. this is because Interform formats can be maintained and used more practicably for a larger number of typical information interchanges. principles of formatting for improved information interchange provide a strong rationale for the designation of Interform format ordering as a preferred convention of usage for ICAS scales of calendar and clock.

interform conventions for the expression of NC-era years consist of a scale identifier followed by a year value: NC 12000. in any case, users should consider the appropriate expression of scalar values as formatted or as natural language expressions.


character delimiters

years and day notations can be designated with or without place separators. specific dates are typically expressed without place separators; however time quantities are typically expressed with place separators.

AAT ICAS English (AAT ICAS 3100) designates a space character as a place separator to avoid confusion among various conventions for the use of commas and periods. however other conventions designate commas or periods as numeric place separators. although pre-scale year notations may be expressed with a hyphen place separator as in the AAT cosmological timeline (AAT ICAS 2036).


usage of metric prefixes

ICAS also specifies the application of metric prefixes for New Calendar expressions of uniform yeargroups. long form expressions of coordinating prefixes should conform with SI principles for standard SI usage and style. in cases where one might use short form expressions of coordinating prefixes for 'ten' and 'hundred' not specified in SI, consider the declaration of a corresponding note:

however those calendrical yeargroups possessing a designated yeargroup term such as 'millennium', 'century', or 'decade' should not be expressed in terms of a standard metric prefix scheme that is reserved to a main unit or a practicable submultiple thereof (even if symbols can be posited in terms of a metric prefix); nor should a calendar year be expressed in terms of metric prefix subunits. calendar years should rather be subdivided in terms of either days, daygroups, months, or other fiscal subunits.

in addition, conventional usage of SI prefixes proscribes the compounding of metric prefixes. users should exercise care in the use of New Calendar expressions such as 'preMium' or 'ten-megalennium' to ensure clarity of expression and to avoid ambiguity. New Calendar expressions should be limited to those specified in the yeargroupUniform termset (AAT ICAS 3115), and users should exercise care not to over-compound expressions. usage for coordinating prefixes 'ten' and 'hun' remains under consideration. usage of coordinating prefix 'pre' moreover remains under consideration as a practical exception in cases such as 'pre-megalennial'.

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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