Unit of Assurance

UnitOfAssurance

Cou2

https://uofa.net/morrison/cou2

Described in packs/vv40/examples/morrison/cou2/uofa-morrison-cou2.jsonld

Fields

@type UnitOfAssurance
uofa:conformsToProfile https://uofa.net/vocab#ProfileComplete
schema:name Morrison COU2 — VAD hemolysis credibility assessment
schema:description V&V 40 credibility assessment for CFD hemolysis prediction of the FDA generic centrifugal blood pump under ventricular assist device (VAD) conditions. COU2 evaluates whether the computational model can predict absolute hemolysis levels for a Class III VAD device at Model Risk Level 5. Higher model risk drives stricter credibility requirements; Monte Carlo uncertainty quantification is performed but all credibility factor gaps remain. Full 13-factor assessment: 7 factors assessed (all with achieved levels below required levels), 6 factors not assessed (flagged as epistemic gaps at MRL 5). Decision: Not accepted.
prov:wasDerivedFrom https://doi.org/10.1115/1.4043024
prov:generatedAtTime 2019-02-01T00:00:00Z
uofa:hash sha256:245b9cb4adec4df51f7a7387779d28c3cfbbe4874e40d28b2a76a81aae946881
uofa:signature ed25519:c0c38e0a660d917cd1b68577c46e7f7392776457e51a2171bd56cb93f0a83901affadbacac05655bb02368d3e1696ad8b87277b4776a657ab9194c60cb4cca04
uofa:signatureAlg ed25519
uofa:canonicalizationAlg json-sortkeys/v1
uofa:hasCredibilityFactor
{"type":"CredibilityFactor","factorType":"Software quality assurance","requiredLevel":3,"achievedLevel":1,"rationale":"ANSYS CFX is a commercial solver with internal SQA processes, but documented evidence of SQA practices was not available to the assessment team at the level required for MRL 5. Achieved Level 1 (commercial solver assumed) vs Required Level 3 (independent SQA audit or third-party certification evidence).","acceptanceCriteria":"Software must meet minimum SQA requirements per V&V 40 Table 3 for MRL 5: documented version control, regression testing, user manual, and independent SQA audit trail.","factorStatus":"assessed","factorStandard":"ASME-VV40-2018"}
uofa:hasCredibilityFactor
{"type":"CredibilityFactor","factorType":"Numerical code verification","requiredLevel":4,"achievedLevel":3,"rationale":"Mesh convergence study performed with GCI. No method of manufactured solutions (MMS) or independent benchmark verification against analytical solutions. Achieved Level 3 (convergence study) vs Required Level 4 (formal code verification with MMS).","acceptanceCriteria":"MRL 5 requires formal numerical code verification including MMS benchmarks, systematic convergence studies, and documented numerical error bounds for all primary quantities of interest.","factorStatus":"assessed","factorStandard":"ASME-VV40-2018"}
uofa:hasCredibilityFactor
{"type":"CredibilityFactor","factorType":"Discretization error","requiredLevel":4,"achievedLevel":3,"rationale":"GCI computed for velocity and hemolysis on three mesh levels. Asymptotic convergence range not formally demonstrated for hemolysis metric. Achieved Level 3 (GCI computed) vs Required Level 4 (formal convergence demonstration).","acceptanceCriteria":"MRL 5 requires quantified discretization error bounds with demonstrated asymptotic convergence and formal GCI for all quantities of interest including hemolysis.","factorStatus":"assessed","factorStandard":"ASME-VV40-2018"}
uofa:hasCredibilityFactor
{"type":"CredibilityFactor","factorType":"Test conditions","requiredLevel":4,"achievedLevel":2,"rationale":"Five flow-speed operating conditions tested, but operating envelope boundaries not systematically explored. Boundary conditions documented but experimental uncertainty on inlet/outlet conditions not fully characterized. Achieved Level 2 (representative conditions) vs Required Level 4 (systematic envelope coverage with quantified boundary condition uncertainties).","acceptanceCriteria":"MRL 5 requires test conditions that span the full intended operating envelope with documented uncertainty on all controlled parameters and systematic boundary exploration.","factorStatus":"assessed","factorStandard":"ASME-VV40-2018"}
uofa:hasCredibilityFactor
{"type":"CredibilityFactor","factorType":"Output comparison","requiredLevel":4,"achievedLevel":2,"rationale":"Hemolysis predictions compared quantitatively against in vitro data at matched operating conditions. However, formal validation metrics with prediction intervals and systematic comparison methodology required at Level 4 were not applied. Achieved Level 2 (quantitative comparison performed) vs Required Level 4 (formal validation metrics with prediction intervals).","acceptanceCriteria":"MRL 5 requires quantitative output comparison with uncertainty bounds on both computational and experimental results, using formal validation metrics and prediction interval methodology.","factorStatus":"assessed","factorStandard":"ASME-VV40-2018"}
uofa:hasCredibilityFactor
{"type":"CredibilityFactor","factorType":"Relevance of the quantities of interest","requiredLevel":3,"achievedLevel":2,"rationale":"Modified index of hemolysis (MIH) is a recognized surrogate for clinical hemolysis but the mapping from MIH to clinical hemolysis outcome is not fully validated. Achieved Level 2 (recognized surrogate) vs Required Level 3 (validated clinical relevance).","acceptanceCriteria":"MRL 5 requires that the quantities of interest be directly linked to clinical endpoints with documented relevance justification.","factorStatus":"assessed","factorStandard":"ASME-VV40-2018"}
uofa:hasCredibilityFactor
{"type":"CredibilityFactor","factorType":"Relevance of the validation activities to the COU","requiredLevel":3,"achievedLevel":2,"rationale":"Validation performed on the same FDA generic pump geometry under operating conditions that match the VAD COU. However, bovine blood analog introduces species-specific hemolysis pathway uncertainty that reduces relevance for human clinical translation. Achieved Level 2 (same geometry, accepted analog) vs Required Level 3 (validated clinical relevance with human-equivalent hemolysis data).","acceptanceCriteria":"MRL 5 requires that validation activities use the same pump geometry, operating conditions, and blood analog as the intended COU application, with demonstrated relevance to human hemolysis outcomes.","factorStatus":"assessed","factorStandard":"ASME-VV40-2018"}
uofa:assuranceLevel Low
uofa:credibilityIndex
{"@value":"0.60","@type":"xsd:decimal"}
uofa:traceCompleteness
{"@value":"1.00","@type":"xsd:decimal"}
uofa:verificationCoverage
{"@value":"0.60","@type":"xsd:decimal"}
uofa:validationCoverage
{"@value":"0.75","@type":"xsd:decimal"}
uofa:uncertaintyCIWidth
{"@value":"0.15","@type":"xsd:decimal"}
uofa:modelRiskLevel 5
uofa:deviceClass Class III
uofa:couName VAD use
uofa:decision Not accepted
uofa:hasUncertaintyQuantification true

References

uofa:bindsRequirement https://uofa.net/morrison/req/hemolysis-safety
uofa:bindsClaim https://uofa.net/morrison/claim/cou2-hemolysis-adequacy
uofa:bindsModel https://uofa.net/morrison/model/ansys-cfx-15-sst-kw
uofa:bindsDataset https://uofa.net/morrison/data/piv-velocity
uofa:bindsDataset https://uofa.net/morrison/data/hemolysis-invitro
uofa:hasContextOfUse https://uofa.net/morrison/cou/cou2-vad
uofa:hasValidationResult https://uofa.net/morrison/validation/mesh-convergence
uofa:hasValidationResult https://uofa.net/morrison/validation/piv-velocity-comparison
uofa:hasValidationResult https://uofa.net/morrison/validation/hemolysis-comparison-cou2
prov:wasAttributedTo https://uofa.net/org/FDA-CDRH
uofa:hasCredibilityFactor https://uofa.net/morrison/cou2/factor/numerical-solver-error
uofa:hasCredibilityFactor https://uofa.net/morrison/cou2/factor/use-error
uofa:hasCredibilityFactor https://uofa.net/morrison/cou2/factor/model-form
uofa:hasCredibilityFactor https://uofa.net/morrison/cou2/factor/model-inputs
uofa:hasCredibilityFactor https://uofa.net/morrison/cou2/factor/test-samples
uofa:hasCredibilityFactor https://uofa.net/morrison/cou2/factor/equivalency-of-input-parameters
uofa:hasDecisionRecord https://uofa.net/morrison/decision/cou2-overall
uofa:criteriaSet https://uofa.net/criteria/ASME-VV40-2018

Integrity

This identifier names a signed package. Verify it yourself against the record in the repository.

uofa check --build packs/vv40/examples/morrison/cou2/uofa-morrison-cou2.jsonld