Tim Bass
08-07-2008 06:39 AM
Our colleagues at Apama share*an interesting*use case, tracking the body*temperature of someone walking in their recent press release.

This use case is a*clear example of a subfunction of complex event processing,*folks*in the mult-sensor data fusion*field (and here at The CEP Blog)*refer to as event (object)*refinement, sometimes called “track and trace.”

The reason we call this processing function “event (object) refinement” is that, in the way the use case was described in the press release, the medical staff are basically tracking body temperature and comparing it to a key indicator to generate an alarm, in this case “body temperature too high.”** This is a simple event, not complex, because the level of inference is quite very low in an overall knowledge hierarchy.

For example, we cannot infer from the alarm that “body temperature too high” is caused by a previous medical condition.* There is no causality at this stage of the game.** We cannot infer from the alarm that the walker has embarked up a steep hill, and the body temperature is expected to exceed a key indicator for a period of time.

Looking at another complex event model,* the system does not (yet) combine all of the body temperatures of the entire group of walkers, correlated by the situation of an approaching thunderstorm, and infer that the walkers have increased their pace because they don’t want to be caught in a driving rainstorm with high winds.

In other words, tracking a single object like “body temperature” is a basic-step in a CEP application, but not really a CEP application yet, because to really be a complex event, there should be some inference of higher knowledge, or estimated situation.*** For example, tracking and tracing the position of an aircraft is good data, but being able to infer the complex situation “potential mid-air crash” between two airplanes is better (defining a complex event vs simply tracking state changes).

Steam processing engines are well suited for track and trace processing of individual event objects, like a walker’s body temperature, or a similar temperature monitoring application from a network device, as demonstrated by the Apama use case.* Tracking events such as “temperature in an object reaches critical threshold” have been going on for decades, in your network, in your car,* in your washing machine, in as spacecraft, just about everywhere we sense-and-respond to temperature changes.

The real marvel of this application was not the event processing on the back end, but in the sensor network, comprised of the human body, an RFID sensor, and a transmission network to a centeralized data collection facility.



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