Monday, August 18, 2008

On Event Processing Description Language

This is a logo of the UK Geologists celebrated their 15o anniversary. I have more modest accomplishment, the Blog dashboard claims that this is my 150th entry into this Blog, that have started almost a year ago (in the one year anniversary, I'll look for some statistics about it)..
In one of the first postings to this Blog I have talked about meta-language for describing event processing behavior as a possible candidate for first standard. Recently, I have been working further on this idea, and soon I'll be able to start talking more about the details (those who heard my tutorial in DEBS 2008 could get a sneak preview. The language is a semantic language whose roots are coming from two directions: the "outside in" direction and the "inside out" direction.
The "outside in" direction is a result of requirement survey that has been done internally in IBM in nine industries, by interviewing IBM domain experts (such as industry CTOs) and in some industries also selected customers. The "inside out" direction is a result of looking at existing event processing languages (both from products and from academic projects) and try to find the union (but also learn something from the interaction), we are now in the process of doing the "inside out" part, while the goal is not to compare language, but to learn from them - it is still interesting to look at different languages and at different assumptions that are reflected in features in the language (example: if the language assumes that the input is a time series, then counting events is equivalent to creating fixed time interval, while in other cases where events arrive in a sporadic/chaotic way these concepts are totally orthogonal). One interesting question is the "effective" expressive power of languages, which is somewhat different from the theoretical expressive power, since - given a specific requirements, with some (or a lot of..) hacking, sometimes adding code, one can achieve this goal, so in comparing language one should use a subjective goal -- how easy to express it / is it a natural language to express it / can a typical developer understand determine how to express it ? maybe it can be translated to a quantitative measures -- length of solution, development time etc...
While the "pattern detection" is certainly the most challenging part of the meta-language, it is by no means the only part - it also includes sections around: event definition, transformation, enrichment etc.. This work also entails various interesting topics to report in this Blog -- more later.

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