Unit of Assurance (UoA) Specification – v0.1

Canonical URL: https://uofa.net

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🧭 Overview

The Unit of Assurance (UoA) is a minimal, semantic data structure that unites a
requirement, model, dataset, validation result, and decision into a single verifiable record.

It is the foundational artifact of the Assurance Alliance
and is designed to make credibility measurable, portable, and machine-verifiable.

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Design Principles

• Minimal: Small enough to read by eye; easy to parse.
• Semantic: Built on JSON-LD for ontology alignment and reasoning.
• Verifiable: Supports digital signatures and content hashes.
• Composable: Many UoAs form an “Assurance Graph”.
• Tool-agnostic: Works with SysML, Simulink, Modelica, CFD/FEA pipelines.

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🧱 Specification

• Format: JSON-LD
• Current version: v0.1
• Namespace: https://uofa.net/vocab#
• License: CC0 1.0

Core Fields

Field	Description
uofa:id	Unique identifier (UUID or hash)
uofa:requirement	Requirement text or URI
uofa:model	Model URI, tool, and version
uofa:data	Dataset source and hash
uofa:validation	Verification/validation result
uofa:decision	Decision and rationale
uofa:signature	Digital signature of the UoFA
uofa:timestamp	ISO-8601 timestamp

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💡 Example

Notes

• Metrics are typed as xsd:decimal by context.
• Provide values as strings (recommended) or adjust SHACL to accept xsd:double if using bare numbers.

{
  "@context": "https://raw.githubusercontent.com/cloudronin/uofa/main/spec/context/v0.1.jsonld",
  "id": "https://uofa.net/example/uoa/OpenFAST-Turbine-042",
  "type": "UnitOfAssurance",
  "conformsToProfile": "https://uofa.net/vocab#ProfileComplete",
  "name": "OpenFAST Turbine Simulation Validation – Complete Profile",
  "description": "Full-profile UoA including model, dataset, dual-twin validation, provenance chain, and graded-assurance metadata.",
  "bindsRequirement": "https://uofa.net/req/REQ-TURB-LoadPredict",
  "bindsClaim": "https://uofa.net/claim/CLM-TURB-LoadPredict",
  "bindsModel": "https://uofa.net/model/OpenFAST-v3.4",
  "bindsDataset": "https://uofa.net/data/NREL-Turbine-Benchmark",
  "hasValidationResult": "https://uofa.net/validation/VAL-2025-04",
  "wasDerivedFrom": "https://uofa.net/uoa/OpenFAST-Turbine-041",
  "wasAttributedTo": "https://uofa.net/org/NREL-Lab",
  "generatedAtTime": "2025-11-02T13:30:00Z",
  "hash": "sha256:a2b4432e3f4a9d8b6f2c5d90b8a0c75e",
  "signature": "ed25519:3efde42c91f...",
  "signatureAlg": "ed25519",
  "canonicalizationAlg": "URDNA2015",

  "credibilityIndex":   "0.93",
  "traceCompleteness":  "0.98",
  "verificationCoverage": "0.95",
  "validationCoverage":   "0.92",
  "uncertaintyCIWidth":   "0.04",


  "assuranceLevel": "High",
  "criteriaSet": "https://uofa.net/criteria/ASME-VVUQ-90",
  "hasDecisionRecord": "https://uofa.net/decision/DEC-2025-07"
}