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

[Wolfgang Laun]

To keep it simple,

declare Trend
   List entries
   int lastValue
   bool hot
end

One rule creates a new Trend with a single entry  if there is a new Entry:

rule newTrend
when
   $e: Entry(...)
   not Trend
then
   create Trend with $e in entries, insert
end

Two to extend or rewind a Trend:

rule extendTrend
when
    $t: Trend( $lv: lastValue )
    $e: Entry( $value: value >= $lv )   // or >
then
   extend Trend, modify Trend
end

rule rewindTrend
when
   $t: Trend( $lv: lastValue )
   $e:  Entry( $value: value < $lv ) // or <=
then
   clear entries, add $e, modify Trend
end


One to discover a "hot" trend:

rule discoverHotTrend
when
   $t: Trend( ! $hot, entries.size >= LIMIT )
then
   hot becomes true, modify Trend
end

I always opt for a simple solution so that I can understand it ;-)

-W

On 03/11/2013, Davide Sottara <dsotty at gmail.com> wrote:
> 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.
>> _______________________________________________
>> rules-users mailing list
>> rules-users at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/rules-users
>>
>
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