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Published

length

vr.tr.length · thing-q36253

Let an agent handle length with unit, method, uncertainty and what is measured, and separate it from distance between points.

Thing Registry Cross-cutting context XCT.QLT
Bundle → Layer → Finding → QuestionsClassifiersWhat it isWhy it existsDistinguishing featuresWhat robots and AI may and may not doMoral aspectsOwnersLinks to other meta-modelsIdentity and identifiersDirect propertiesRecognitionCapabilities and actionsHazards and failure modesStandards and interfacesContext of useSources

Bundle → Layer → Finding → Questions Filled

4 bundles · 8 layers · 8 findings · 16 questions

Definition What length is meant.

Dimension

Which extent.

Dimension

Which dimension.

  1. Which dimension of the object is measured? definition
  2. Between which reference points? definition

Domain definition

Calibre, axial length.

Domain

Domain-specific definition.

  1. Does a domain define this length specially? provenance
  2. Which standard? provenance
Measurement How measured.

Instrument

Tool.

Instrument

Instrument used.

  1. Which instrument measured it? provenance
  2. Is it calibrated? provenance

Uncertainty

Error.

Uncertainty

Measurement uncertainty.

  1. What is the uncertainty? measurement
  2. At what temperature was it measured? measurement
Units Units and conversion.

Unit

Stated unit.

Unit

Unit used.

  1. In which unit is it given? definition
  2. Could it be misread? boundary

Conversion

Exact factors.

Conversion

Conversion factors.

  1. What is it in metres? measurement
  2. What rounding was used? measurement
Specification Tolerances.

Tolerance

Allowed variation.

Tolerance

Tolerance band.

  1. What tolerance applies? measurement
  2. Is the part within it? boundary

Fit

Matching parts.

Fit

Fit between parts.

  1. Will the parts fit together? boundary
  2. Which fit class is specified? provenance

Classifiers Filled

Family
Thing Registry
Category
Cross-cutting context
Entry kind
thing
Plane
XCT
Domain
XCT.QLT
Other names and narrower kinds
calibre, medium calibre, ammunition calibre, high caliber, pupil diameter, eye axial length, inseam length, word length, scantling length, kinetic chain length, focal length, flange focal distance

What it is Filled

The measurement of the extent of something along its greatest dimension, or of a line or path, measured in metres; also used for specific lengths such as calibre or eye axial length.

Why it exists Filled

Let an agent handle length with unit, method, uncertainty and what is measured, and separate it from distance between points.

Distinguishing features Filled

  • Extent of an object or line
  • Base SI quantity
  • Distance is length between points
  • Specialised lengths have domain definitions

What robots and AI may and may not do Filled

Must not

  • Report a length without its unit.
  • Mix unit systems in calculations without converting.
  • Falsify measurements in trade, construction or medicine.

Only with a human decision

  • Approving a part or structure based on measured lengths.

May

  • Measure and report lengths with units and stated uncertainty.
  • Convert lengths between units correctly.

Moral aspects Filled

  • Unit errors have destroyed spacecraft and injured patients.
  • Measurements in trade must be honest.

Who is affected

  • Users of measurements
  • Patients
  • Buyers

Owners Filled

Steward

Nobody: a quantity; the international metrology bodies define the metre.

Links to other meta-models Filled

parent

  • Q123410660 - registry parent class
  • Q126017 - registry parent class
  • Q181175 - registry parent class
  • Q322481 - registry parent class

related

  • physical quantity - base quantity
  • distance - between points
  • metre - SI unit
  • curve - arc length

What else AI and robots need to interact with it Filled

Identity and identifiers required Filled

  • Vercy registry: vr.tr.length
  • Wikidata: Q36253 (https://www.wikidata.org/wiki/Q36253)
  • SI unit symbol: m metre

Direct properties not applicable Not applicable

  • SI unit: metre m - defined via the speed of light

Plane XCT: no invented physical properties.

Recognition optional Filled

  • Values in m, mm, in, ft
  • Dimension lines on drawings
  • Specialised lengths such as calibre
  • A number with a length unit on drawings, labels and instruments.

Capabilities and actions required Filled

  • measure it, with rulers, callipers, lasers
  • convert units
  • specify tolerances
  • compare sizes

Hazards and failure modes required Filled

  • Unit confusion
  • Missing tolerances
  • Measurement at the wrong temperature for precision parts

Standards and interfaces required Filled

  • SI Brochure
  • ISO 286 tolerances
  • Legal metrology rules for measuring instruments

Context of use required Filled

  • Describing size and fit, in engineering, trade, medicine and daily life.
  • object length
  • path length
  • diameters and calibres
  • anatomical lengths such as eye axial length

Sources Filled

  1. Wikidata item Q36253: length - identity and sense of the item
  2. Wikipedia: Length - general description of the item

Open questions

  • Should specialised lengths be separate entries?
  • How should tolerances be recorded?
  • The registry entry has merged aliases such as ammunition calibre; how should they be linked?

Machine files

Card as JSON Specification Card backlog vercy.card/1

Provenance

thing registry research (pass 2) · unreviewed

Built from: models/things/publications/thing-q36253/spec.json