Complex events "can be anything from a sequence of temperature readings to something like the First World War, which was a very complex event indeed." -Dr. David Luckham
David Luckham -- considered the "father of complex event processing" -- recently joined Dr. K. Mani Chandy, Rodney Morrison, and Beth Gold-Bernstein for an informative panel discussion on the relationship between EDA (Event Driven Architecture) and SOA. The panel, part of ebizQ's recent Event Processing Virtual Conference, which brought together the leading thinkers and proponents of EDA and Complex Event Processing (CEP).
The panelists were divided, however, over the extent of the role of human involvement in complex events.
Chandy, for example, said that human engagement is essential at some point in the complex event processing cycle. "I’ve seen quite a few applications, but almost none in which there is no human involved" For example, Chandy said, "in military applications, when there is a gun or device is fired to kill somebody. It’s always done with a human being responsible for their final action."
As Chandy pointed out:
"I think its absolutely critical for human beings to be part of this sense and respond system. It's important how the application supports the human being if you're looking at trading or fraud detection. In all these cases, its really important to have a human being involved. Fraud is one case where you might have an application that informs a credit card user that something inappropriate may be going on, without having a human being first check that."
Luckham, however, pointed out that there are many events are processed independent of human intervention. "There are many examples of event driven architectures where there are absolutely no humans whatever," he said. "The CPU on your computer is an event driven architecture, believe me. And its entirely event driven, clocked, without a human in the loop.
EDA is part of SOA on two different levels, Chandy said:
"One way that I’ve seen EDA used in conjunction with SOA is for service management. Many SOA vendors are exposing metrics that can give you information like end to end process time and activity times. Those metrics can be provided to a CEP system to help control and manage those services. I can, for example, do dynamic provisioning for a service that's getting maxed out."
Chandy also connected the dots between EDA and SOA. "If SOA means loosely coupled subsystems with very clean interfaces, so that new systems could be coupled into the substrate. Then EDA events fit within that framework, because EDA is also based on a loose framework, and is extensible." In a request-reply SOA scenario, "then EDA can still be coupled. There will be layering between the push and the pull parts."
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