[rules-users] [drools-fusion] Detecting a Trend in Data

[Davide Sottara]

Quick ideas (not tested):

1) Detect an always increasing trend:
ensure that no previous value - possibly scoped by a sliding window - is
greater than the current

$current : MyPoint( $val : value )
not MyPoint( value > $val, this before $current ) over window:length(3)


2) A more robust approach, allowing for some noise:
create a custom accumulate function that computes a (linear) regression
and returns a
data structure with the basic output parameters (regression
coefficients, confidence intervals, etc..)
You would then constrain on that... something like

when
   LinearRegressionData( k > .... ) from accumulate ( $x : MyPoints()
over window:length(3),
                                                                       
             myCustomLinearRegressionAccumulateFunction $x ) )
then

Other options might be possible
Davide





On 11/03/2013 10:21 AM, code4dc wrote:
> Hey guys,
>
> I am trying to come up with a way to get Drools to detect a trend in a
> dataset. The data is very basic and looks something like this:
> (each row represents an object in the WM)
> Time          Value
> 10:00            1
> 11:00            2
> 12:00            3
> 01:00            1
> 02:00            3
> 04:00            4
> 05:00            5
> 06:00            3 
>
> I want to set up a rule that detects when there is an upward trend in the
> value for 3(configurable) or more consecutive data points. 
>
> It's easy to set up a rule to detect when there is a two consecutive rows
> and the 2nd one has a higher value. But how can I set up a rule to detect
> when there are multiple consecutive rows each with a higher value than the
> previous one? 
>
> Any ideas are welcome(even if they are not complete!).
>
> Thanks
>
>
>
>
> --
> View this message in context: http://drools.46999.n3.nabble.com/drools-fusion-Detecting-a-Trend-in-Data-tp4026609.html
> Sent from the Drools: User forum mailing list archive at Nabble.com.
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