anchor.diff:  :jbake-status: published
   :jbake-tags: blog, alerts, alerting, advanced, nelson
   
  -== Modelling Conditions
  +== Modeling Conditions
   
  -Hawkular Alerting offers several types of link:http://www.hawkular.org/community/docs/developer-guide/alerts.html#_conditions[Conditions] for defining Triggers. Most of the Conditions deal with numeric data, but String, Availability and Events are also supported.
  +Hawkular Alerting offers several types of link:http://www.hawkular.org/community/docs/developer-guide/alerts.html#_conditions[Conditions] for defining Triggers. Most of the Conditions deal with numeric data but String, Availability and Event data are also supported.
   
  -Modelling scenarios for detecting behaviours is highly dependent of the nature of the Domain that is being represented. So, that means some Domain might require simple Conditions based in Numeric thresholds to efficiently detect unexpected situations.
  +Modeling scenarios for detecting behaviours is highly dependent on the nature of the Domain being represented.  The Domain may only require simple numeric threshold conditions to efficiently detect unexpected situations.
   
  -In other cases, identifying when a metric has some unusual variation that leads into a potential problem can be a non trivial task.
  -A represented magnitude may vary in patterns difficult to express with simple thresholds; then it is needed additional tools to identify trends that may lead into potential problems.
  +In other domains, it can be non-trivial to identify unusual metric variations that may lead to a problem.
  +Simple thresholds are not expressive enough to detect metric patterns or trends that can identify potential problems.
   
   == Nelson Rules
   
   Hawkular Alerting supports Conditions based on link:https://en.wikipedia.org/wiki/Nelson_rules[Nelson Rules] to enable advanced detection on Numeric metrics.
   
  -These rules are based on the mean and the standard deviation of the samples and offer additional techniques for modelling complex scenarios.
  +These rules are based on the mean and the standard deviation of the samples and offer additional techniques for modeling complex scenarios.
   
   For example,
   
  
positive.code: image::../../../../../assets/img/blog/2017/nr3.png[Nelson Rule 3]
  endif::[]
  
  A trend has been detected.
  
  === Rule 4
  
  
negative.code: 
  Applying Nelson Rules in our scenario can help to detect potential "out of control" situations.
  
  But as discussed, modeling scenarios are highly dependent of the nature of the Domain; applying Nelson Rules is a useful tool to help identify a problem.  Although, the alerts are predictive and a Domain's Analyst may need to evaluate the quality of the model.