Legacy Issue Number: 17472
Source: VDMbee ( Henk de Man)
Add the following attributes to Measurement, to enable expression of measurement precision, and stochastic aspects of measurements: “confidence interval upper bound”, “confidence interval lower bound”, “confidence” (being a probability) and “distribution”(string).
Reported: SMM 1.0 — Fri, 13 Jul 2012 04:00 GMT
Disposition: Resolved — SMM 1.1
The RTF discussed this issue (at length) and found a resolution which addressed the core concern within the issue while preserving the general design pattern of SMM. The following was considered to further accommodate stochastic measurement:
Stochastic measurement (e.g. in the context of simulation) usually comes with large sets of Measurements. SMM does already support that a large set of Measurements is “summarized”. Example: 10000 Measurements are the basis for a CollectiveMeasurement (which expresses the mean or some other accumulation). For scalability reasons there should still be a way to reach out to the large set of Measurements, without populating these Measurements in the model itself. Leaving the base Measurements out of the model is already possible via value “false” for attribute “isBaseSupplied” of a CollectiveMeasurement. Reaching out to the (external) base Measurements can be facilitated by an additional association “baseQuery” (analogous to defaultQuery).
To take stochastic Measurements based on SMM, a separate Measure would be defined, whereby stochastic methods may implemented via Operation of the Measure. In SMM, Arguments of an Observation serve as parameters to the Operation. In order to be able to vary stochastic parameters within an Observation, Arguments can, additionally, be associated with ObservedMeasure. This will give a practical and SMM-compliant way to handle Operation parameters, both stochastic parameters and parameters in general.
Hence, resolution is twofold:
Both Observation and ObservedMeasure can have Arguments associated.
Add baseQuery to non-direct Measurement, whereby baseQuery is an Operation that specifies a query that can used to determine the base measurements of a non-direct Measurement when isBaseSupplied = false. baseQuery is optional even when isBaseSupplied = false and isBaseSupplied is inapplicable when isBaseSupplied = true. baseQuery and defaultQuery should not create inconsistencies. Directly supplied base Measurements would always have precedence. baseQuery would have secondary precedence and defaultQuery has the lowest precedence. The two queries then present two different ways of cutting off the supplied Measurements. defaultQuery allows a user to cut off base Measurements of Measurements of a given Measure. baseQuery allows a user to cut off the base Measurements of a given non-direct Measurement.
Updated: Wed, 8 Jul 2015 11:44 GMT
SMM11 — Attributes to be added to Measurement
- Key: SMM11-125
- OMG Task Force: Structured Metrics Metamodel (SMM) RTF