Choosing Elements

Choose an element by the engineering statement you want to preserve.

Statement	Element kind
“A nurse programs therapy.”	Actor plus OperationalActivity
“The patient needs controlled analgesia.”	Need (needKind: stakeholder)
“The pump shall enforce a bolus limit.”	Requirement (requirementKind: system)
“Evaluate the requested bolus.”	LogicalFunction
“Dose-management responsibility.”	LogicalComponent
“Dose-control firmware image.”	FirmwareItem
“Unintended over-infusion.”	Hazard
“Independent maximum-dose monitor.”	RiskControlMeasure
“Verify lockout interval enforcement.”	VerificationCase
“Approved test report 2.1.”	Evidence

A reliable naming pattern

requirement reqBolusLimit : Requirement {
    attribute :>> id = "REQ-025";
    attribute :>> requirementKind = RequirementKind::system;
    attribute :>> name = "EnforceBolusLimit";
    attribute :>> statement =
        "The pump shall reject a bolus request that exceeds the configured limit.";
}

• reqBolusLimit is the SysML reference name.
• REQ-025 is the lifecycle-stable engineering identifier.
• EnforceBolusLimit is a concise display name.
• statement contains the reviewable obligation.

Common distinctions

Need versus requirement: a need expresses a stakeholder outcome; a requirement makes a bounded, verifiable obligation.

Function versus component: a function says what transformation occurs; a component says who or what owns responsibility.

Hazard versus harm: a hazard is a potential source of harm; harm is the injury or damage.

Verification versus evidence: a verification case describes the check; evidence records the result or artifact.

After choosing elements, connect them with typed relationships.