Geoscience Reference
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Fig. 7.13 The schematic diagram of the monitoring system for search and detection of the time of
the start of the OAS phase transition
From the above-introduced criterion for the approach of the OAS phase change,
it is clear that the form and behavior of I
Ω
it are characteristic of each type of the
process that is taking place in the OAS environment. One of the complex problems
consists in determination of these forms and their corresponding classi
cation. For
instance, the dangerous natural phenomena, such as landslides and mud
ows, have
characteristic indicators of preliminary changes of relief and landscape. These are
recorded from satellites (in the optical band) and together with the data of aircraft
survey and ground measurements of relief slopes, expositions of slopes and state of
hydro-network, are used to predict them several days before their occurrence.
However, in the OAS case, such indicators are lacking. Therefore, it is necessary
to de
fl
ne the parameter a
ij
as a function of the OAS phase state. This dependence is
the relationship between the OAS indicator instability calculated for i-th and j-th
measuring stations and is expressed as the ratio:
a
ij
¼
I
T
ðu; k
i
;
t
Þ=
I
T
ðu
j
; k
j
;
t
Þ
ð
7
:
1
Þ
In this case, the main problem is focused on the determination of the informative
space
and the formalization of the investigation procedure in the monitoring
system (Fig.
7.13
). This procedure has the following scheme. The holder registers
data from sensors and keeps the
Ω
elements in the memory accordingly
with some algorithm. Decision maker analyses data delivered by holder and decides
what character of these data
“
suspicious
”
—
it is signal about the start of the OAS phase change or
it is noise. Then, the
finder taking into account the output of the decision maker
localizes the anomaly and starts to coordinate the functions of the holder and
decision maker on the data speci
cation for the detected anomaly. Finally, if an
anomaly (suspicion about the OAS phase transition) with duration
ned
empirically) is detected the decision maker decides about the start of the OAS phase
˄
(that is de
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