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Published

unit of measurement

vr.tr.unit-of-measurement · thing-q47574

Let an agent handle units by quantity, system, definition and conversion, and never report a number without a unit.

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 Which unit.

Unit

Name and symbol.

Unit

Unit identity.

  1. Which unit, with which symbol? definition
  2. What quantity does it measure? definition

System

SI or other.

System

Unit system.

  1. Which system does it belong to? definition
  2. How is it defined? provenance
Conversion Between units.

Factor

Exact factor.

Factor

Conversion factor.

  1. What is the exact factor to SI? measurement
  2. Is it exact or approximate? boundary

Consistency

Dimensions.

Consistency

Dimensional check.

  1. Are units consistent in the calculation? boundary
  2. What checks catch errors? action
Use Choosing units.

Choice

Appropriate units.

Choice

Unit choice.

  1. Which unit suits this audience and context? action
  2. Is a legal unit required? boundary

Machine-readable

Codes.

Machine

Unit codes.

  1. Which UCUM or QUDT code represents it? provenance
  2. Is it used consistently? boundary
Safety Critical errors.

Medicine

Dose units.

Medicine

Dose units.

  1. Are dose units clear, avoiding error-prone abbreviations? boundary
  2. Which guidance applies? provenance

Engineering

Design errors.

Engineering

Engineering checks.

  1. Could a unit error cause a failure here? boundary
  2. How is it prevented? action

Classifiers Filled

Family
Thing Registry
Category
Cross-cutting context
Entry kind
thing
Plane
XCT
Domain
XCT.QLT
Other names and narrower kinds
look, type of year, typed page, unit of mass density, unit of power, United States Pharmacopeia unit, non-SI unit, off-system measurement unit, multiple of a unit, unit of solid angle, unofficial unit of measurement, metric unit

What it is Filled

A definite magnitude of a quantity, defined and adopted by convention, used as a standard for measurement, such as the metre, kilogram, second or pharmacopoeia units.

Why it exists Filled

Let an agent handle units by quantity, system, definition and conversion, and never report a number without a unit.

Distinguishing features Filled

  • Standard magnitude of a quantity
  • Organised in systems
  • SI is the international system
  • Some units are domain-specific

What robots and AI may and may not do Filled

Must not

  • Mix units in calculations without converting them.
  • Present an obsolete or local unit as standard.
  • Round or convert doses or loads in a way that changes their safety.

Only with a human decision

  • Changing the units used in medical, engineering or legal measurements.

May

  • Convert between units using defined factors and state the units used.
  • Check that values carry the correct units.

Moral aspects Filled

  • Unit errors have caused medication overdoses, structural failures and lost spacecraft.
  • Fair trade depends on honest measures.

Who is affected

  • Patients and users of measured products
  • Engineers and traders

Owners Filled

Steward

Nobody: a convention; the international system of units is maintained by the international bureau of weights and measures.

Master systems

  • The International System of Units

Links to other meta-models Filled

parent

  • Q181175 - registry parent class
  • Q39875001 - registry parent class
  • Q71550118 - registry parent class

related

  • physical quantity - quantity
  • hand, cup, cable - units
  • SI - system
  • measurement - practice

What else AI and robots need to interact with it Filled

Identity and identifiers required Filled

  • Vercy registry: vr.tr.unit-of-measurement
  • Wikidata: Q47574 (https://www.wikidata.org/wiki/Q47574)
  • UCUM code: code strings machine-readable units
  • QUDT unit IRI: URI semantic units

Direct properties not applicable Not applicable

Not applicable

Plane XCT: no invented physical properties.

Recognition optional Filled

  • Unit symbols and names
  • Systems: SI, imperial, US customary
  • Special units such as USP units
  • Symbols such as m, kg, s, and names on instruments and labels.

Capabilities and actions required Filled

  • convert between units
  • check dimensional consistency
  • choose appropriate units
  • trace units to definitions

Hazards and failure modes required Filled

  • Unit conversion errors
  • Missing units
  • Confusing similar units

Standards and interfaces required Filled

  • SI Brochure
  • ISO 80000
  • Legal metrology law

Context of use required Filled

  • Making measurements comparable.
  • SI base and derived units
  • non-SI units accepted with SI
  • imperial and US customary units
  • domain units such as pharmacopoeia units

Sources Filled

  1. Wikidata item Q47574: unit of measurement - identity and sense of the item
  2. Wikipedia: Unit of measurement - general description of the item

Open questions

  • Should units be instances with UCUM codes?
  • How should non-SI units be linked?
  • The registry entry has merged aliases such as look; should they be removed?

Machine files

Card as JSON Specification Card backlog vercy.card/1

Provenance

thing registry research (pass 2) · unreviewed

Built from: models/things/publications/thing-q47574/spec.json