# AAT ICAS 2010 ✧ overview of key standards

this document provides a general overview of AAT ICAS systems and is not intended as a specification or reference of the ICAS systems standards. for references and detailed specifications of the ICAS systems described, please see the pertinent AAT ICAS specifications documents.

- general description
- overview of ICAS terms
- overview of New Calendar (NC)
- overview of NC years corresponding to Gregorian calendar
- overview of NC years corresponding to Julian calendar
- overview of New Calendar leap years
- overview of uniform yeargroups
- overview of day notation
- overview of Uniform calendar (UC)
- overview of years
- overview of uniform months
- overview of uniform daygroups
- overview of Inter-Dial Clock (IDC)
- overview of main unit
- overview of dial units
- overview of decimal dial units
- table 2010.1 ✧ methods of decimal expression
- overview of SMH time
- overview of localized time

## general description

Integrated Chonological Applications System (ICAS) develops a metric paradigm for representing calendar and clock formats for more practicable representations of time data. because ICAS scale formats are easy to write and clear to read, ICAS standards can accommodate usable improvements in ways that people can process time and date information.

ICAS is developed to advance standards for metrication, usability, and communication. ICAS standards are promoted as voluntary preferred standards of measure with reference to claims of 'ICAS in use' as a fundamental principle. AAT does not pursue the 'reform' of pre-ICAS calendars and clocks.

as an emerging development in the use of metric scales of measure, ICAS also represents a state of the art in the design and use of calendar and clock applications, incorporating multiple schemes of uniformity and a scrupulous commitment to matters of learning and use.

ICAS specifies a Uniform Calendar (UC), an Inter-Dial Clock (IDC) system, a New Calendar (NC), and other standards that can be accessed from the AAT ICAS web site at http://www.aatideas.org/icas via Internet. Alliance for the Advancement of Technology (AAT) administers and promotes the applicable use of ICAS in accordance with its mission as an educational organization. AAT has approved the use of ICAS by AAT for purposes of programming and quality management.

## overview of ICAS terms

the use of terms relating to the use of calendars and clocks include ICAS system terms, traditional system terms, and other related words and expressions. ICAS and other scale terms may possess characteristics of scale, alphanumeric, case, and sequence sensitivity.

- scale sensitive—an attribute of a term for which the 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.
- scale insensitive—an attribute of a term for which the 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.
- context sensitive—an attribute of a term for which the 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 representation—an attribute of a term or format designating whether a scale value is represented alphabetically or numerically. numeric representation also concerns the use of arabic or roman numerals, and so forth.
- case sensitivity—an attribute of a term or format designating the significance of case information for a particular application or method: 'cs' denotes case-sensitive ('a' and 'A' are parsed as different); 'ci' denotes case-insensitivity ('a' and 'A' are parsed as identical); 'cn' denotes not subject to case (for example, number characters or special characters); 'ca' denotes element or attribute indicates case information; 'ct' denotes reference to type definition for information about case.
- sequence sensitivity—an attribute of a term with regard to a specific term set. the use of uniform months as data elements may be considered to be subject to a strict sequential scheme, while the use of uniform yeargroups such as centuries identifying a historical epoch may not be subject to a strict sequential scheme.

some ICAS system identifiers include:

- ICAS designates Integrated Chronological Applications System.
- IDC designates Inter-Dial Clock.
- NC designates New Calendar era.
- NDN designates New Calendar Day Notation.
- UC designates Uniform Calendar.
- UCA designates use of the millennial-place digits of the uniform tenmillennium yeargroup NC 10000-19999 for coordination of Uniform Calendar years subject to the Gregorian calendar: Uniform Calendar year UCA 2003 corresponds to Gregorian calendar year AD 2003.
- UCN designates use of the Uniform Calendar for any New Calendar-era date: UCN 12003 (AD 2003).

## overview of New Calendar (NC)

New Calendar (NC) methods for the specification of years and days accommodate the use of coherent positive scales for dates throughout the histories of world societies. principles for the use of the New Calendar can be applied to determine factors of calculation among other calendar systems. the NC scale is designated as a principal ICAS era scale.

### overview of NC years corresponding to Gregorian calendar

a New Calendar system era is derived from the Gregorian calendar (AD era) via the correspondence of NC 12000 to AD 2000. Gregorian calendar years may thus be factored to NC-era years by adding 10 000. the system identifier term 'NC' may be used to designate the use of the New Calendar for a date in the NC era.

### overview of NC years corresponding to Julian calendar

New Calendar dating of years corresponding to the Julian calendar, precursor of the Gregorian calendar, is subject to the different calendar scales used for various years in different regions from AD 1582 to 1923. the Julian calendar was introduced in AUC 709 (BC 45), the Julian AD scale was established in AD 532, and the BC scale was described in AD 722. a year zero was not designated between the AD and BC scales, and thus BC-era years may be approximated to NC-era years by subtracting from 10 001. additional calculation factors may however apply with regard to the different methods for determining leap year days, new years days, and tropical correction days.

### overview of New Calendar leap years

determination of a leap year in the New Calendar system is derived from the Gregorian calendar system. all Gregorian calendar leap years are also leap years in the New Calendar system.

### overview of uniform yeargroups

uniform yeargroups are yeargroups such as a decade, century, or millennium that in a primary sense are fixed coherent to yeargroup sequences in relation to year NC 00000 of the New Calendar.

### overview of day notation

a system of New Calendar Day Notation (NDN) is derived from the New Calendar scale of years, and is counted from the first day of year NC 00000 at IDC t000 deka(0). UCN 12000A01 at IDC t250 deka(0) may be designated in day notation as NDN 4382912.25 or as NDN 4382912t250.

## overview of Uniform Calendar (UC)

Uniform Calendar (UC) methods for the designation of uniform months, uniform daygroups, and days integrate schemes from the Gregorian calendar with a number of uniform schemes. principles for the use of the Uniform Calendar can be applied to determine factors of calculation among other calendar systems. the UC scale is designated for use in ICAS with the New Calendar (NC) year scale.

### overview of years

Uniform Calendar years are designated in terms of a New Calendar year or yeargroup scale:

- UCN designates use of the Uniform Calendar for any New Calendar-era date: UCN 12003 (AD 2003).
- UCA designates use of the millennial-place digits of the uniform tenmillennium yeargroup NC 10000-19999 for coordination of Uniform Calendar years corresponding to the Gregorian calendar: Uniform Calendar year UCA 2003 corresponds to Gregorian calendar year AD 2003.

dates corresponding to the Julian Calendar can be expressed in terms of the UCN era, however those dates occurring in the tenmillennium yeargroup NC 10000-19999 (circa BC 1 to AD 9999) may also be expressed in terms of the UCA era.

### overview of uniform months

a Uniform Calendar year is comprised of twelve uniform months of 30 days, counting from the first day of a New Calendar year, with the remaining yearend days and any leap day grouped at yearend into the 12th uniform month.

### overview of uniform daygroups

a daygroup is a method by which days are grouped within a month. uniform months in the Uniform Calendar may be divided into uniform daygroups that may be designated in terms of localized element sets per ICAS. uniform daygroups begin daygroup sequences from the first day of a uniform month. daygroups include:

- a uniform block (7-day) daygroup comprised of 4 uniform block daygroups plus 2 monthspace days grouped into a 30-day uniform month,
- a uniform stack (6-day) daygroup comprised of 5 uniform stack daygroups in a 30-day uniform month,
- a uniform track (5-day) daygroup comprised of 6 uniform track daygroups in a 30-day uniform month.

the 7-day Gregorian week daygroup may also be used with the uniform months of the Uniform Calendar; however must only be used in the Uniform Calendar in conformance with the weekdays in the Gregorian calendar.

## overview of Inter-Dial Clock (IDC)

Inter-Dial Clock (IDC) methods for the designation of time integrate schemes for the decimal expression of times coherent to a main unit of one day. the IDC scale is designated as a principal ICAS time scale.

### overview of main unit

the main unit of the IDC system is derived from a duration of one day in the traditional clock system of 24 hours. time in the IDC system is expressed in terms of a decimal value of the time elapsed from midnight. for example, a local time of noon corresponds to a time value of 0.5 of the IDC main unit.

### overview of dial units

an IDC main unit is further designated in terms of a dial unit, which designates how a main unit is divided into smaller units. as in the traditional clock dial, IDC dials are divided into major and minor clock units. major clock units designate a primary subdivision of the main unit. minor clock units designate the subdivision of major clock units. subminor clock units moreover designate the subdivision of minor clock units.

### overview of decimal dial units

decimal expressions in the IDC system may be designated in terms of a decimal dial, specifically in terms of decitriads. decitriads consist of an order specifier character or character group that is systematically related to an ordinal group of three decimal places of the main unit, for example, t000 tt000 ttt000. the first decitriad t000 designates the first group of three decimal places of the main unit (0.XXX), the second decitriad tt000 designates the second group of three decimal places (0.xxxXXX), the third decitriad ttt000 designates the third group of three decimal places (0.xxxxxxXXX), and so on. decitriad expression is preferred and encouraged for emerging uses of IDC, however decimal point expression (0.5 main IDC) may also be used where practicable.

table 2010.1 ✧ methods of decimal expression

method | expression | decimal places |
---|---|---|

first decitriad | IDC t000 | tenth, hundredth, and thousandth |

second decitriad | IDC tt000 | ten-thousandth, hundred-thousandth, and megaeth |

decimal point expression | IDC 0.5 main | place is designated via decimal point |

abridged decitriad | 0_{tt}00 or 0tt00 |
thousandth, ten-thousandth, hundred-thousandth |

### overview of SMH time

time that is expressed in seconds, minutes, and hours may also be described relative a dial model; however SMH time as such is not expressed as a decimal relative the main unit. for example, SMH time is configured to a 24-hour dial (or 2 repetitions of a 12-hour dial), with 60 minutes per hour and 60 seconds per minute. SMH time is thus not a coherent nor a semi-coherent decimal expression of the main unit.

### overview of localized time

localized time is expressed in the form of an offset from Universal Time (UT).

zoneDeka localizations reference a global system that consists typically of 20 zones. particular deka(z) localized times may be expressed within -t450 and +t500 difference from UT, or as applicable.

zoneZodiac localizations reference a global system that is derived from a model of 24 SMH standard international time zones, each typically representing one hour difference of solar time, using the standard midnight in a zone as a basis for determining IDC zoneZodiac time. special implementations of SMH time zones such as daylight savings time or winter time are also expressed relative UT.

with reference to good or best practices for data-interchange, users can also specify the use of a particular localized time zone with reference to the time zone for another location.

aatideas.org document updated:

scale | value | ||
---|---|---|---|

UCN | 12011 P09 Violet | ||

zone(UT) | t408 tt900 | ||

'ICAS in use' can accommodate calendar and clock formatting 'for all people, for all time'. | |||

AD common year day | 039 | ||

G | 2011 February 08 Tuesday | ||

UT | 09:48:49 | ||

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