meMO
meMO / mee-moh

Medical Engineering Modeling Ontology

Safety evidence should stay true when the system changes.

A SysML v2-native ontology and toolchain that keeps a medical device's safety evidence aligned as the design changes — typed, computable, and architecture-backed.

memo:: 0.2.0 · open source · SysML v2 · ISO 14971 · IEC 62304 · ISO/IEC/IEEE 42010

The problem

The artifacts remain. The meaning drifts.

Risk files, requirements, architecture notes, tests, and release records change on different cadences. After a design change, teams must still defend one complete thread: what changed, what it affects, where the control is implemented, and which evidence is still fresh.

A trace link often says only that two things are related — not how. A requirement "traces to" a test, but does the test verify the requirement, the implementation, or a risk control? Generic links cannot carry that distinction.

Evidence thread under change
Intended useassumptions and operating context shift
Risk controlpaper controls need concrete allocation
Architectureinterfaces, modes, timing, and behavior evolve
Verificationcoverage and acceptance criteria can go stale
The review question: what evidence is still valid?

The answer

Architecture-backed safety threads.

meMO makes the safety argument explicit and checkable. Every node is typed. Every edge is a semantic link with a verb, roles, and status. Change impact is computed from typed relationships, not reconstructed from meeting memory.

Need
Requirement
Architecture
Behavior
Risk Control
Verification
Evidence
View

The stack

Four layers, adopt what you need.

Standards coverage

Built for regulated medical devices.

ISO 14971

Hazards, harms, risk controls, risk matrices, residual risk, risk management file views, and closure rules for hazard-control-verification chains.

IEC 62304

Safety classification (A/B/C), software architecture layers, verification obligations, and lifecycle-stage scoping.

ISO/IEC/IEEE 42010

Architecture viewpoints, views, stakeholder concerns, and architecture decisions.

IEC 81001-5-1

Cybersecurity threat modeling, trust boundaries, vulnerability/mitigation links, and impact-on-safety connections.

Resources

Learn, explore, contribute.

Presentations, source code, and documentation to get started with meMO.

Create. Compile. Assure.

Author the model, compile the checks, and keep the safety case assured as the design changes.