Files
boc/docs/design/adr/ADR-011-Four-Layer-Data-Architecture.md
T
Bernt 754c89506b ADR-011: Four-Layer Data Architecture — Raw Archive → Knowledge → Ontology → Decision
- Layer 1: ArchiveArtifact — immutable original with retention policy
- Layer 2: KnowledgeArtifact — extracted knowledge (observations,
  segmentations, feature vectors, relations)
- Layer 3: Knowledge Graph / Ontology (documented, not implemented)
- Layer 4: Decision Intelligence (existing DecisionCase)
- DataLifecycle: tracks every step with artifact lineage
- Key principle: AI models trained on curated datasets, not whole archive
- Ontology answers 'what does it mean in our domain?'

Long-term goal: Every observation converted once to structured
knowledge, reused infinitely for analysis, decisions, training.

Next: PR-005A — Minimal Mission Import UI for MVP-0
2026-07-02 16:03:39 +00:00

2.1 KiB

ADR-011: Four-Layer Data Architecture

Status

Accepted

Context

We need a clear separation between raw data, extracted knowledge, and decision intelligence to avoid building expensive, tightly-coupled AI systems.

Decision

Separate into four layers:

Layer 1: Raw Archive (cheap, immutable)

  • Original files never changed
  • Hash guarantees integrity
  • Storage policy: active (30 days) → archive (long-term, cheaper)

Layer 2: Knowledge Extraction

  • Objects, geometry, GPS, classifications, bounding boxes, embeddings
  • Observations and Evidence created
  • Structured knowledge used for most queries, not video files

Layer 3: Knowledge Graph / Ontology

  • Road A12 → has Observation → Crack → belongs to Area → Stockholm
  • Answers: "Show all main roads where cracking increased last 12 months"
  • Comes from knowledge graph, not by reading video files

Layer 4: Decision Intelligence

  • Verified Decision Cases
  • Curated datasets for AI training
  • Business impact tracking

Key Principles

  1. Archive Artifact = Original file, never modified
  2. Knowledge Artifact = Extracted knowledge, can be re-generated
  3. Ontology before model — taxonomy answers "what does it mean in our domain?"
  4. AI models trained on curated datasets, not whole archive

Data Lifecycle

Upload → Immutable Archive → Metadata Extraction → Knowledge Extraction
→ Ontology Mapping → Decision Pipeline → Learning → Archive Retention

Each step produces a new Artifact with version history.

Long-term Goal

"Every real observation is converted once to structured knowledge and can then be reused infinitely for analysis, decision support, history, training, and future AI models."

Consequences

Positive

  • Raw data = revisionable archive
  • Real product = growing knowledge base + verified Decision Cases
  • Can swap AI models without losing originals
  • Cheaper storage (archive vs active)

Negative

  • More complex pipeline
  • Need to manage extraction models
  • Knowledge graph maintenance
  • ADR-002: Artifact is common base contract
  • ADR-003: Event Sourcing for traceability