The distribution Attribute is used for defining the probability density functions associated with reliability data. Since traditional assessments of a design's diagnostic capability (such as testability analysis) do not require probability density data, this information is not used within most eXpress analyses. However, when distribution data is included in an eXpress design, it will be used by the simulation engine in eXpress OSS. The editing dialog for distribution Attributes (displayed below) can be invoked by clicking on one of the "Edit Default" buttons on the Attribute Definitions dialog (the same fields appear on the right side of the Attributes panel when editing the value of a distribution Attribute for a specific element in the design).
Normal
Factor x - Use the factor boxes to control the parameters of the selected function.
Graph - The graph shows the distribution curve for the selected function and factors.
Standard
Normal
Same as normal except
sigma is set automatically
to lambda / 4.
Graph - The graph shows the distribution curve for the selected function and factors.
Exponential
Graph - The graph shows the distribution curve for the selected function and factors.
When the Edit Default Button is selected in the Attributes Definitions window Theselected Attribute Value window shown below will open allowing the type of Distribution to be selected.
If the chosen Doistribution type is Normal or Weibull, the Factor window will open (as seen in the windows above so), the Analyst can set the desired Factor X which determines the range [the probability of the random variable falling within a particular range of values] of the Distribution.
Function Drop Box - Use this drop box to select the desired probability density function. The following functions are available:
