Wednesday, October 15, 2008

On semantics of synonyms

Holidays time - and I had to spend time in replacing my home wireless router (not of the same firm that is shown in the picture) who did not work well - to get another expensive one, whose signal is not received well in the lower floor well -- I hate wasting my time on restore things to work, this is never-ending story, every time something else need fix... we need more robust appliances..

Well - back from my personal frustrations to event processing thinking. I have posted a couple of postings about the different possible interpretations of "event_1 occurs before event_2", however, different interpretations are not unique to temporal issues, and the specific anomaly of having different temporal semantics. Let's take a case in which time does not matter - the function defined this time as follows:
Detect a pattern that consists of conjunction of two events (order is not important) - e1, e2.
e1 has two attributes = {N, A}; e2 has also two attributes = {N, B} ; the pattern matching is partitioned according to the value of N (on context partitions I'll write another time).

For each detection, create a derived event e3 which includes two attributes = {N, C}; E3 values are derived as: E3.N := E1.N ; E3. C = E1. A * E2. B.

Let's also assume that the relevant temporal context is time-stamps = [1, 5] - and the events of types E1 and E2 that arrived during this period are displayed in the table below:

The question is: how many instances of event E3 are going to be created, and what will be the values of their attributes? Think about it -- I'll discuss it next week.