Re: [rules-users] sliding window question

On Feb 27, 2014, at 1:01 AM, Wolfgang Laun <wolfgang.laun(a)gmail.com&gt; wrote: The correct way to ascertain that something hasn't happened for a certain interval must be based on "staking out" this interval. One way is by means of two distinct events: when $r1: Reading( reading >90 ) $r2: Reading( reading > 90, this after[30s] $r1 ) not Reading( reading <= 90, this after $r1 && before $r2 ) then Clearly, this will only work if Readings arrive regularly, and you may have a certain amount of delay at the end. Another way would be to use a sliding window over time: when not Reading( reading <= 90 ) over window:time( 30s ) then Here's a snag, too: If there are no readings at all, you'll also get an alert. And then you'll have to think about the seconds following the 30th second: should another alert be emitted repeatedly... Most of the time, it's not an issue in CEP ;-) -W > On 27/02/2014, lin.lin <lin.lin(a)comcast.net&gt; wrote: > Hi, > > I tried to create a rule that gives an alert when a machine reading is high > for 30 seconds. I modeled the machine reading input as events. The > following is the rule: > > rule "rule1" > dialect "mvel" > when > $rd1 : mReading( reading >90 ) from entry-point ReadingStream > not ($rd2 : mReading (reading<=90 , this before [0s, 30s] $rd1 ) > from entry-point ReadingStream ) > then > System.out.print ("alert: Reading high for 30 seconds \n"); > end > > This does not detect detect the bad reading. However, If I changed the > rule > to be following (change second condition from "not" to "exists"), it > detects > all readings that are good. > > rule "rule1" > dialect "mvel" > when > $rd1 : mReading( reading >90 ) from entry-point ReadingStream > exists ($rd2 : mReading (reading<=90 , this before [0s, 30s] $rd1 ) > from entry-point ReadingStream ) > then > System.out.print ("alert: Reading high for 30 seconds \n"); > End > > > Is this an issue in CEP or did I do something wrong? > > Thanks a lot! > Lily > > > > -- > View this message in context: > http://drools.46999.n3.nabble.com/sliding-window-question-tp4028367.html > Sent from the Drools: User forum mailing list archive at Nabble.com. > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users