I think that a parcel (a field) needs to be a static fact, perhaps not maintaining a single state but two states, previous and current. Events are state changes and sensor readings.<br><br>Now, if sensor readings are dangerous for state A and if the last state change is not much distant from the sensor readings you can still raise an alarm. I also think that a "state change" in a field is not a single point in time; states overlap in a (large) field, as one part may be sunnier or drier or... as other parts. Clearly, this complicates rules, but I think that the whole problem cannot be handled in an absolutely discrete manner.<br>
<br>-W<br><br><br><div class="gmail_quote">On 15 November 2010 13:56, Anais Martinez <span dir="ltr"><<a href="mailto:amartinez@iti.upv.es">amartinez@iti.upv.es</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br>
<br>
The system is receiving readings from real sensors of humidity, temperature,<br>
etc.. There are a lot of rules for deciding if a specific plague or illness<br>
affects (or can affect) to the plants or not: One condition of those rules<br>
is the plants' status, because the illnesses affect to the plant depending<br>
on its status. I have defined Status, Reading and Risk as events.<br>
<br>
Well. Supose than the system has just passed from status "A" to status "B",<br>
and after that, it has received several readings from sensors whose values<br>
are a risk for an illness in the status "A" but not in "B". Then, the<br>
system has not activated the Risk, because it thinks that the current status<br>
is "B". Therefore, if the farmer inserts an status "B" after those readings,<br>
the system has not activated the Risk but that readings are dangerous. In<br>
that case, how do i say that there is a Risk?<br>
<br>
Thanks again.<br>
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