Trend Analysis using VibWorks : Extrapolation

Trend Analysis using VibWorks : Extrapolation

VibWorks comes embedded with tools helping you to assess quickly the current health of your assets. and that includes a powerful Curve Fitting and Extrapolation method. 

In order to access this feature, when in Database Management, simply hit the F key on your Keyboard  with one of the indicators window selected.

This Box will appear: 



Linear Extrapolation

Using linear Method, the algorithm will use the Last N measurement to find the best Linear (order 1) fit for the data subset, and Extrapolate for One year past your last point (the blue curve).

Then the algorithm will detect the exact timing to Cross the Warning, Alarm and Danger level (if they are ever to be crossed during the next year).

in the following exemple, using the last 3 measurement for a linear extrapolation, only the warning line will be crossed , in 55 days. 


Polynomial Extrapolation 

mainly based on Lagrange formula, the polynomial fitting uses the following : 



You can choose the order of the analysis between  2 to N-1    , N being the population size you are using in the Last field.  
the Order must be smaller than the number of samples you are considering, and order 1 is the same as using linear method. 

The following show the application looking at the last 4 measurements and using Order 3 




If we consider all the points in the trend (6 points), and change the order accordingly (5 = 6-1) 


 

it is clear that using the last 4 points results in a better approximation, the regression rate is smaller compared to the the second case. 
The exercise requires a good knowledge of data interpretation and interpolation. do not hesitate to try on different subsets, and to detect abnormal regressions applied on your Data.  








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