It is from this operational asymmetry that complexity in event processing is required. In other words, as distributed networks grow in complexity, it is difficult to determine causal dependence when trying to diagnosis a distributed networked system. Most who work in a large distributed network ecosystem (cyberspace) understand this. The CEP notion of “the event cloud” was an attempt to express this complexity and uncertainly (in cyberspace).
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X. Dong, and M. Godfrey. ICPC '08: Proceedings of the 2008 The 16th IEEE International Conference on Program Comprehension, page 33--42. Washington, DC, USA, IEEE Computer Society, (2008)