Casestudie Breakdown prediction Contell PILOT - Transumo

Figure 4-1: General Overview of the Generalized Approach ([Daßler95], p. 22) (adapted)
The approach starts like every analyzing method with collection and storage of
measurement data over time. As this approach is meant to be general, no
requirements or restrictions are defined for this activity. ([Daßler95], p. 23)
The biggest problem of analyzing measurement data is the influence of outliers on
calculated results. According to the author, these outliers are evoked by technical
disturbances. The following list contains some major causes: (Daßler95] p. 52)
• Short-term measurement connection failures or short-circuits
• Short-term sensor failures
• Unstable working voltage
• …
As outliers are able to falsify calculated results, the elimination of these outliers is the
first proposed step of measurement data analysis. A big problem is the recognition of
outliers because nearly every measurement data is faced with noise, which causes
small perceptible deviations. To identify outliers, the distance between succeeding
measurement values is determined and compared to each other. These distances
only vary marginal in case of a constant noise. To be able to classify a measurement
value as an outlier a threshold value has to be found. The suggestion is to use the
two times averaged distance between the succeeding measurement values as
described by Formula 4-1. (Daßler95] p. 54)
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