Elements

Choose an element by asking what kind of statement you are recording.

Selection guide

You are recording…	Prefer…	Avoid…
A person or external role	Actor	A component named “User”
A user outcome	Need (needKind: stakeholder)	A premature software requirement
A measurable system obligation	Requirement (requirementKind: system)	A vague function name
A transformation	SystemFunction	A component unless responsibility is the point
A solution-independent responsibility	LogicalComponent	A vendor-specific hardware part
Implemented software	SoftwareComponent, SoftwareModule, or SoftwareDeploymentUnit	A generic logical component
A potential source of harm	Hazard	A failure mode or harm
A design measure that reduces risk	RiskControlMeasure	A requirement with no risk link
A testable assurance activity	VerificationCase	An evidence file by itself
A test result or approved record	Evidence	An unstructured URL

Definition versus usage

MEMO provides definitions such as Requirement, Hazard, and LogicalComponent. Your project creates usages that specialize those definitions and set the kind attribute that records the level of the claim:

requirement reqOcclusionAlarm : Requirement {
    attribute :>> id = "REQ-042";
    attribute :>> name = "OcclusionAlarm";
    attribute :>> requirementKind = RequirementKind::system;
    attribute :>> statement =
        "The pump shall issue a high-priority alarm after detecting occlusion.";
}

Naming pattern

Use three complementary names:

• the SysML usage name (reqOcclusionAlarm) for references;
• a stable engineering identifier (REQ-042) for lifecycle continuity;
• a short human name (OcclusionAlarm) for views and tables.

Keep the full normative claim in statement or the appropriate descriptive attribute. Do not force a sentence into the usage name.

One element, one principal meaning

Split an element when its clauses have different verification methods, allocations, safety classifications, or lifecycle states. Keep it together when splitting would destroy one coherent engineering claim.