Saturday, May 24, 2008

On CEP agent in EPN

This logo shows that we are not alone in the world of TLAs - there are other who use this acronyms, once I have made a list of acronyms of EDA which has shown that this is not a very good choice of acronym, but an acronym these days is context-sensitive. Anyway -- talking about "event processing networks", which we now try to clean its definitions - we have talked about SEP (simple event processing) agents, MEP (mediated event processing), CEP (complex event processing) and IEP (Intelligent event processing). The names can still change, I am not happy about any of them, but it seem to be relatively intuitive, and can be explained to non-technical people quite easily. Anyway, this time I'll concentrate on what is CEP agent. CEP agent have two basic phases:

1. Detect patterns over multiple events (these can be either multiple events of the same type, or multiple events from multiple event types - some are doing distinction here, but I don't see the rationale behind it) - this creates a collection of event-instances that satisfy the patterns.

2. Derive events as a function of the collection of events created in phase 1.

Some comments:

  • There can be cases in which one of the two capabilities is used in a degenerated form. The pattern can be trivial (take all events without any pattern), but still a derivation (e.g. count, calculate the average of a certain attribute etc...) is required; on the other hand - the pattern can be complex, however the derivation is trivial (just a concatenation of all participating events).
  • The term for the result of phase 1 - can be called "composite event" or "complex events", the two are not exactly synonyms, according to the glossary, as composite event is a syntactic term that is created by operators from primitive events, whereas complex event is a semantic term that includes aggregation of events that may not be obtained from patterns - however, the definition of phase 1 results is consistent with both.
  • A CEP agent always lives within a context (temporal, spatial, semantic) -- most common type of context is a time-window, but the concept of context is much wider.
  • The semantics of a CEP agent need to be fine-tuned in order to pick the instances of events participating in patterns relative to other possibilities which require to define policies - I'll talk more about semantics fine-tuning is a later postings.
  • The result of a CEP agent is one or more derived events (consistent with other types of agents).

1 comment:

Ernest Eugster, Ph.D. said...


I have a Ph.D. student who is studying CEP. Would anyone be interested in being a reader. The position is paid. If you have a Master's or better with CEP experience, pls contact me:

Ernest Eugster, Ph.D.
Regis University
Denver, CO USA