AAT ICAS 2022 ✧ UC usage guidelines
this document describes normative AAT ICAS usage guidelines for the Uniform Calendar (UC) system. please refer to AAT ICAS 2020 for additional important usage guidelines, and other AAT ICAS standards for Uniform Calendar specifications and element sets.
- Uniform Calendar usage guidelines
- table 2022.1 ✧ long and short forms of Uniform Calendar terms
- usage of month and year scales
- usage of uniform months
- usage of uniform daygroups
- preferred formats for the expression of calendar dates
- practicable usage of year formats
- biennial implementation of uniform months
- practicable usage of Interform formats
- practicable usage of Continental formats
- expression of inclusive dates
- table 2022.2 ✧ expression of inclusive dates
Uniform Calendar usage guidelines
Uniform Calendar terms and expressions should be used to represent uses of UC scales, methods, and applications. a short form representation of a date (for example, 6A28) is unambiguous if one has established the year in terms of the era and the decade (for example, UCN 12009) for a particular use. thus short forms should only be used if the long forms are readily established. it is also important that the format of the short form is established as a date format.
table 2022.1 ✧ long and short forms of Uniform Calendar terms
| short form | long form |
|---|---|
| UC | Uniform Calendar |
| UCN | [NC-era representation of UC date] |
| UCA | [millennial representation of current NC tenmillennium era for UC date—for coordination of years subject to the Gregorian calendar] |
| bk | uniform block daygroup (uniform 7-day) |
| sk | uniform stack daygroup (uniform 6-day) |
| tk | uniform track daygroup (uniform 5-day) |
| wk | Gregorian week daygroup (Gregorian 7-day) |
usage of month and year scales
Uniform Calendar dates should only be expressed in terms of New Calendar or New Calendar yeargroup scales. Uniform Calendar dates should not be expressed in terms of Gregorian or Julian calendar year scales. moreover, the UC, UCN, and UCA calendar terms are reserved for expressions of Uniform Calendar dates.
- UCN 12003V11 (NOT )
- UCA 2003V11 (NOT , NOR )
these guidelines do not however specify the expression of Gregorian or Julian calendar dates in terms of New Calendar or New Calendar yeargroup scales. the Gregorian and Julian calendar month scales are conventionally expressed in relation to traditional year scales. representations of traditional month scales may be expected to be represented in relation to traditional year scales. in cases where both ICAS and traditional dates are expressed within a single implementation or document, users should consider the specific representation of ICAS scale dates in terms of ICAS scales, and traditional scale dates in terms of traditional scales. in any case the applications or methods concerning the usage of both ICAS and traditional calendar month and year scales should ensure that the usage of any particular scale of year, month, or day is clearly represented.
usage of uniform months
normative usage for uniform months should be represented in the form of alphabetical expressions. the initial character of a uniform month is capitalized by convention.
to reinforce and ensure ease of distinction among calendar units, numerical forms should be reserved for daynumbers and yearnumbers. however ordinal expressions of uniform month may also be used appropriately in natural language expressions ("the yearend occurs in the twelfth month") or as expressions of intermediate calculations (formula or reference).
developers and users should consider the representation of uniform months as 'uniform months' rather than as 'months', particularly in situations where usage may be expected to concern both uniform and traditional scales.
the month and day-of-month components of Uniform Calendar dates are designated with exactly three format characters*: an alphabetic character for the month and two numeric characters for the day-of-month. to promote clarity and to ensure consistency of expression, day-of-month should always be formatted and expressed to 2 places, even if the first place is a '0'.
- Interform format order is ICAS preferred—UCN 12003V11; A01, A02, A03 OR A 01-03 or A 01, 08
(BUT NOT ) - inclusive date range—A01-A15 (NOT )
- Continental format—11 V 2003 UCA; 01A, 02A, 03A or 01 A, and so forth.
(NOT , NOR )
usage of three format characters concisely provides both month and day information, helps to indicate use of a Uniform Calendar scale, and helps to ensure that expressions of particular Uniform Calendar dates are more readily clear. moreover, developers should consider the design of formats for ranges of dates to represent the uniform month term for each component date.
*for a default implementation of a biennial set of 24 uniform months. the use of an annual implementation of a uniform month set calls for the use of an additional annual set character designation: for example, eee-a yyyy am dd ; UCN-a 12004aD01- annual.
usage of uniform daygroups
usage for Uniform daygroups or daygroup days should be represented in the form of lexical expressions, not in the form of numerical expressions. Numerical forms should only be used in support of lexical form expressions of uniform daygroups.
- uniform block daygroup (NOT )
- blockday White (NOT )
- the block daygroup is a uniform 7-day daygroup of the Uniform Calendar (in comparison with the week daygroup that is a 7-day daygroup that is observed independent of the months and years of the Greogiran and Uniform calendars).
the use of numbers or numerical expressions for the normative usage of uniform daygroups or daygroup days should be avoided. the use of numerical forms for Uniform Calendar units should be reserved for daynumbers and yearnumbers.
the initial character of a uniform daygroup or a uniform daygroup day is capitalized by convention. developers and users should consider the representation of uniform daygroups as 'uniform daygroups' rather than as 'daygroups', particularly in situations where usage may be expected to concern both uniform and traditional scales.
a strict relation among daygroup days and daygroup groups of days has not been specified in ICAS. the term 'yearend' has a special meaning in relation to any of the uniform daygroups. the term 'monthend' has a special meaning in relation to the 'block' daygroup, and might also usefully refer to the days of the monthend and fourth blockend combined.
users should be aware of different conventions for designating the beginning or ending of a daygroup. ISO 8601 describes different conventions for beginning a calendar week on a Sunday or on a Monday. a weekend is conventionally Saturday and Sunday (unless a special schedule is in effect). yet the beginning of a calendar week is often determined by convention. ICAS has appropriated terms 'blockend', 'stackend', and 'trackend' for general use by users. ICAS has not specified a requirement for any particular tabular design for a calendar. the specification of a standard 'beginning' or 'end' of a daygroup sequence may however be regarded to be subject to normative determination by users.
preferred formats for the expression of calendar dates
those who process much date and time information can realize more of a use for practicable calendar formats. users should thus reference good or best practices for data-interchange. please refer to ISO 8601 specifications for representing numerical dates and times for the Gregorian calendar and 24 hour clock dial. please also refer to AAT ICAS 2021 for additional information about Interform ordering as a preferred convention.
practicable usage of year formats
developers and users should consider the use of best practices for the representation of years and year scales. guidelines in reference to Y2K specify the usage of year formats for purposes of specificity and to avoid issues of scale overflow. contracted forms of year scales (the use of a subset of the numerical places for expressing a year scale, for example, '03' representing year 'UCA 2003', or 'UCA 2003' representing year 'UCN 12003') should only be used if the use of a particular year scale is explicitly established, and if contraction does not result in scale overflow (the '03' of '2003' is parsed as '1903'). in cases where the calendar methods and applications for dates span across yeargroups such as centuries, millennia, or tenmillennia; then the specific millennial or tenmillennial place digits should be represented.
although experienced users may be accustomed to distinguishing particular dates among a variety of different formats, and the use of a contracted year form may not result in confusion for common or typical dates, special care should be exercised in the representation of years for methods of software development and for historical dating. in cases where the contracted form of a year scale might appear similar to a date of an earlier or other year scale, then the full year scale digit places should be represented, even if they are leading zeroes (for example, NC 02003 is 10 000 years earlier than NC 12003 expressed as UCA 2003).
users should moreover consider the use of year scales appropriate for the comparison of dates in other year scales. dates corresponding to the 4-digit UCA scale may be appropriate for comparison with dates corresponding to the Gregorian calendar AD scale. to facilitate an easier comparison of dates throughout different eras, one may also determine expressions for AD- and BC-era years in terms of NC-era dates.
biennial implementation of uniform months
developers and users should consider the implementation and use of a biennial implementation of uniform months (AAT ICAS 3120) for the Uniform Calendar.
preliminary usability evaluations suggest that a biennial implementation of the Uniform Calendar offers three principal advantages over the annual implementation: better support for annual calendaring (use of even and odd year sets more practicably supports the specific expression of date values in contexts spanning more than one year); capabilities for biennial calendaring; and aesthetic considerations relating to the use of a larger month set. experienced users may find that these features and conditions can accommodate improvements in ways that users can reckon the validity or value of date expressions, thus facilitating a reduction of certain types of errors.
practicable usage of Interform formats
developers and users should consider the use of Interform date formats for Uniform Calendar dates. Interform expresses a uniform or natural format order in relation to the arabic number system that is represented in terms of largest-unit places to smallest-unit places. Interform is thus highly appropriate for the usage of times and dates as data. yet regardless of which format order is used, calendar dates should be expressed unambiguously.
the expression of both date and time in one format is best served by Interform. users should thus reference good or best practices for data-interchange. ISO 8601 specifies numerical date and time formats for traditional scales for purposes of data-interchange.
because Interform formats can readily accommodate the representation of dates and times that are clear, concise, and logically sortable; usability evaluations have shown Interform to be more practicable in terms of use, design, implementation, organization, readability, and maintenance. developers and users should moreover consider the use of Interform formats for conventional use.
practicable usage of Continental formats
developers and users should consider the appropriate use of Continental date formats for conventional expressions of Uniform Calendar dates. continental expresses a semi-uniform or semi-natural format order in relation to the roman alphabet that is represented in reference to an alphabetical order. continental formats may be appropriate for conventional expressions of dates and times that are presented in lexical form, for example, in dialogues or for document titles.
- blockday Green, the 11th day of uniform month V, in the year 2003 of the UCA tenmillennium
- <title>uniform month V of 12003 UCN</title> [title of web calendar document]
expression of inclusive dates
table 2022.2 ✧ expression of inclusive dates
| system | format | range | example |
|---|---|---|---|
| UCA | Interform | inter-year | 2003U01-2004F30 |
| 2004-05 Winter North | |||
| inter-month | 2004 G27 - H12 | ||
| 2004 GJ | |||
| intra-month | 2004 K 14-20 | ||
| note: Interform formats are noted here as preferred methods for the expression of inclusive dates; or for the expression of dates occurring across various calendar units of year, month, day, season, and so forth. | |||
| G | Interform | inter-year | 2003 June 30 - 2004 June 28 |
| 2004-05 Winter North | |||
| inter-month | 2004 July 27 - August 09 | ||
| 2004 August-September | |||
| intra-month | 2004 October 10-16 | ||
aatideas.org document updated:
| scale | value | ||
|---|---|---|---|
| UCN | 12019 S19 Yellow | ||
| zone(UT) | t339 tt050 | ||
| 'ICAS in use' can accommodate calendar and clock formatting 'for all people, for all time'. | |||
| AD common year day | 139 | ||
| G | 2019 May 19 Sunday | ||
| UT | 08:08:14 | ||
| style legend | |||
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