# AAT ICAS 2043 ✧ IDC calculation factors

this document describes AAT ICAS calculation factors for the Inter-Dial Clock system. please refer to AAT ICAS 2040 for additional important information about conversion scale guidelines. please also refer to AAT ICAS 2330 for additional important information about IDC methods for scheduling and metering.

- Inter-Dial Clock calculation factors
- determination of significant units
- calculating clock times
- table 2043.1 ✧ some Inter-Dial Clock formula resources

## Inter-Dial Clock calculation factors

a number of general and specific methods for formatting and factoring dates and times are described in a variety of other resources including operating system documentation, application documentation, UNIX manual pages, APIs for Java and other languages, ISO 8601, and so on.

developers and users should consider any scale factors among different dial units and across different functions of localized time. the use of a particular method of factor calculation may involve the following considerations: whether a particular time is derived from a particular IDC dial-unit or a SMH dial; whether the designation or observance of a particular localized clock time is based on a particular IDC dial or a SMH dial; and whether the designation or observance of a particular clock time is based on a dial-unit, a decimal value, or a localized time scale. if a particular clock time is based on a decimal value, then the particular method of decimalization calls for consideration.

## determination of significant units

developers and users should consider the determination of significant units for either an IDC or a SMH scale. if a SMH scale tolerance is not smaller than a whole-unit tolerance of 1 millichron, then clock values that are significant to the minute in a SMH scale may be considered to be practicable for factoring to the millichron in an IDC scale. IDC scale tolerances of 1 millichron may be considered to be practicable for factoring to scale tolerances of 1 minute in an SMH scale, as no precision is lost.

factoring from SMH to IDC for which a SMH scale tolerance is smaller than 1 millichron should be factored to a smaller significant unit such as a tokochron, tikochron, microchron, and so forth. clock values that are significant to the IDC tikochron may be considered to be practicable for factoring to the SMH second, insofar as a whole-unit tolerance of 1 tik is smaller than a whole-unit tolerance of 1 second. however the conversion to whole-unit tolerances of clock values from the SMH second to the IDC tikochron are subject to the increased precision of the IDC tikochron.

developers and users should consider that appropriately determined IDC scales can represent precision more practicably than SMH scales for any designated level of scalar precision, where practicability is determined in terms of an expression of precision per clock unit place for a designated level of scalar precision.

## calculating clock times

calculate an IDC time from SMH by determining the particular numerator and denominator values for a SMH clock time in relation to a main unit of 1 day and then calculating the decimal value for an IDC clock time. designate the significant SMH scale units to be factored to IDC, for example, factoring from the minute or from the second. the denominator should be in terms of the number of designated SMH standard units in a day for calculating the SMH time to an IDC time in terms of the main unit. the numerator should show the number of designated SMH units from midnight to the time to be factored. for example, the numerator corresponding to 6:30 pm (a value expressed to the minute would be [60 minutes x 18 hours] plus 30 minutes) is 1110 minutes; while the denominator (60 minutes x 24 hours) is 1440 minutes. [1110 minutes]/[1440 minutes] is approximately IDC 0.7708 main or t771 to the nearest millichron.

factor from IDC to a SMH time by noting a particular IDC time as a decimal expression of the main unit. select the particular SMH scale units to be calculated, for example, to the minute or to the second. multiply the IDC time value by the number of designated SMH scale units equalling a main unit (1440 minutes or 86 400 seconds). then determine the particular SMH time from the result. for example, t770 calculated to the minute (0.770 main unit x 1440 minutes) is 1108.8 minutes corresponding to 18 hours 28.8 minutes into a day, or 6:29 pm to the nearest minute.

please see AAT ICAS 2045 for some IDC to SMH calculation tables, AAT ICAS 2046 for some SMH to IDC calculation tables, and AAT ICAS 2047 for some local time calculation factors.

table 2043.1 ✧ some Inter-Dial Clock formula resources

resource | formula |
---|---|

resource | formula |

for any serial time method for a clock time timeICAS (timeIDC, timeSMH, and so forth), for any first decitriad tXXX, for any second decitriad ttXXX, (please refer also to AAT ICAS 2041 and -2042 formula resources): | |

serial time method | timeICAS corresponds to a decimal representation of the portion of the day from the beginning midnight to a clock time. |

first decitriad | tXXX corresponds to the first three decimal places of a clock serial time: 0.XXXxxxxxx (tenth, hectoeonth, and kiloeonth places). |

second decitriad | ttXXX corresponds to the second three decimal places of a clock serial time: o.xxxXXXxxx (ten-kiloeonth, hundred-kiloeonth, and megaeonth places). |

special note: ensure that decitriads are always represented to 3 decimal places, even if the beginning places are leading zeroes. also ensure that for a representation of a decitriad that the last significant place is appropriately rounded if rounding is appropriate. |

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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