Net Station Waveform Tools - College of Education & Human ...

17: Segmentation
Figure 17-8 shows an incorrect way to define this specification.
Criteria Set 1
****
****
****
1
3
**** 5
****
Criteria 1 list
7
Temporal relation
Event To Select:
Figure 17-8. Incorrect segmentation specification
The specification in Figure 17-8 is incorrect because it provides oversimplified
instructions to Net Station. It uses one criteria set to define both position and
condition, and assumes that the software will understand that you want event pairs
only where the resp occurs immediately after the **** event.
Instead, based on its segmentation logic (see Figure 17-6), Net Station interprets this
as a request to find the first resp event that follows an **** event, even if other events
separate them. Rather than the two correct event pairs, this specification produces
four pairs (see Table 17-1).
Table 17-1. Incorrect specification definition
Criteria Set 1 Criteria Set 2 Temporal relation Answer Event pair
**** 1 resp 4 Is resp 4 the first resp event after *** 1? yes 1 and 4
**** 3 resp 8 Is resp 8 the first resp event after *** 1? no
**** 5 Is resp 4 the first resp event after *** 3? yes 3 and 4
**** 7 Is resp 8 the first resp event after *** 3? no
Is resp 4 the first resp event after *** 5? no
Is resp 8 the first resp event after *** 5? yes 5 and 8
Is resp 4 the first resp event after *** 7? no
Is resp 8 the first resp event after *** 7? yes 7 and 8
To approach this correctly, you must use two criteria sets to describe the second event,
which comprises a specific position and a specific condition.
136 Net Station Waveform Tools Technical Manual S-MAN-200-WFTR-001 • December 21, 2006
resp
resp
resp
Criteria 2 list
Criteria Set 2
1st 2nd 3rd 4th
5th 6th 7th 8th
9th 10th 11th 12th
4
8