Verification – System Engineering

Administrative Independence

A condition in which two organizations intentionally do not share some particular set of goals. Administrative Independence is usually established to at least partially substantiate that one of the two organizations can plausibly provide cognitively unbiased witnessing of execution by the other. The witnessing group is often rigidly process-oriented, with many intermediate opportunities to document... read more

Confirmation Bias

The (possibly unwitting) cognitive search for, filtering and interpretation of information that will support prior conclusions or belief. The reason that “independent verification” exists as a concept.

Demonstration

The direct observation of an item for unquantified functionality without use of intrusive instrumentation, fixtures, or excitation. Applicable IFF the characteristic specified is externally observable and need not be quantified. In theory, we want to do demonstrations at the highest level of system aggregation for which the function is directly observable (in order to provide... read more

Deviation

A prior granting of permission to fail before any official attempt (see run for score) to verify compliance with an allocated technical requirement. Use of a deviation avoids giving the appearance of changing the requirement and is, therefore, an important component of an Acquisition Customer’s Pearl Harbor File and (also therefore) much despised by developers.... read more

Inspection

(1) Direct observation of the article without the use of intrusive instrumentation. Applicable IFF the characteristic specified is both quantifiable and externally observable. This sense is applied only as part of “line QA“, through mandatory features found on the article’s identifying drawing. (2) When used in the context of Qualification, direct observation of the identifying drawing... read more

Residual Uncertainty

“Residual Uncertainty” is the uncertainty that remains after formal verification is complete: the adverse difference between the limit value of a requirement measure and the proven value at the limit of Uncertainty for that same parameter. It is distinct from other uncertainties that exist during the development process. At that adverse extreme, the requirement must still... read more

Run for Score

A specific test event in which data are gathered on a UUT for explicit, formal verification of compliance with one or more requirements. This phrase is less often used with respect to verification by other methods, but is sometimes used in those other methods when referring to data gathered in support of some subsequent analysis that verifies compliance.

Simulation

Simulation is a type of analysis proceeding through chains of events or circumstances (that is, as a matter of cause-and-effect). The term is often used when the solution of time-domain ODE’s is required to calculate an end state, or a series of intermediate states. It can, however, be used with respect to other independent variables... read more

Test

The indirect observation of the item using intrusive instrumentation, fixtures or external excitation that may alter the behavior of the item. Applicable IFF the characteristic specified is quantifiable and the test method has a known effect on the item’s behavior. See also demonstration for a discussion about selecting levels of aggregation for any given test... read more

Test Article

A now mostly-obsolete synonym for UUT.

Uncertainty

Uncertainty expresses the extents of the range within which a value can exist, quoted as a distribution about some nominal value. The magnitude(s) of the uncertainty in any given situation can be influenced by (for example) the calibration accuracy of an instrument, or the numerical precision of a calculation. Unlike tolerance, the concept of uncertainty... read more

Unit Under Test (UUT)

The article being tested1. Synonymous with Test Article. Footnotes or demonstrated[↩]

Validate

Unfortunately, this is one of those “overloaded” terms having more than one meaning, depending on context. In the context of Requirements Management, the concept of validation generally stems from Software Systems Engineering usage1. In that context, “technical requirements” were more or less hypothetical until Footnotes It was not normally used in legacy System Engineering practices... read more

Verification Analysis Cycle (VAC)

The project-specific sequence of analyses repeated during development as a leading indicator of successful compliance with requirements. Ideally, the VAC should use analysis methods and tools that are different than those used in support of design in order to minimize susceptibility to systemic errors, but that can really drive a project’s cost. Contrast with DAC... read more

Verification Cross-Reference Matrix/Index (VCRM, VCRI)

Legacy development specifications typically organized their verification sections according to activity. In that case, it was necessary to indicate which verification requirements were relevant to each of the design-to requirements, each of which was considered to have been fully verified when all verification requirements indicated in the VCRI were successfully completed. This specification practice resulted... read more

Verification Fundamentals

The concept and objective of Verification in the System Engineering context is introduced. The classical abstract "methods" are defined, along with the basic analytical process for assigning any given method to any given claim. read more.

Verification Measure

A measure for which the following are true: (1) Any combination of the algorithm, meta-arguments, or input arguments are distinct from and independent of those used to evaluate the Technical Requirements or support the design process for the dingus. (2) Those algorithm elements and input arguments that quantify features of the design are traceable to... read more

Topic: Verification