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Figure 4. Connection between Development Methodology and Application Domain
described via this model covers the perception of
sensor features (
Signal Assessment
) up to evalu-
ation of detected situations (
Impact Assessment
)
which can be seen as the highest level of situation
awareness (Endsley M. R., 2000).
To demonstrate the applicability of the JDL
Data Fusion Model in the AAL domain, the fol-
lowing example is used: An elderly person, who
lives in an AAL equipped home, wears a tracking
sensor and uses a walking aid which is equipped
with a localization sensor. The sensors allow the
tracking of the person's and the walking aid's
location. In addition, the walking aid contains a
sensor that indicates its orientation (standing or
lying). The target of this use case is to detect the
situation, when the person has fallen down the
stairs while the walking aid is still lying on top
of the stairs.
In L0 (
Signal Assessment
), incoming raw data
is processed and matched to defined features (i.
e. attributes of objects). Attributes always have
certain values and are related to one or multiple
entities.
In L1 (
Object Assessment
), the attributes are
matched to their corresponding entities. In the ex-
ample the attribute location is set to
End-Of-Stairs
for the entity person and to
Beginning-Of-Stairs
for the entity walking aid. The walking aid's at-
tribute orientation is set to
Lying
. The mentioned
situation
Person has fallen down the stairs
could
be described in an informal way as follows:
Critical:= Is(Person, End-Of-Stairs) AND
Is(WalkingAid, Beginning-Of-Stairs)
AND Orientation(WalkingId, Lying)
This expression can be read as: A critical situa-
tion occurred, when the person
Is
in the basement
nearby the
End-Of-Stairs
and the walking aid is
lying (
Orientation(WalkingId, Lying)
) at the begin-
ning of the stairs (
Is(WalkingAid, Beginning-Of-
Stairs)
). The term
Is
represents a location relation
while the term Orientation is an object's value.
In L2 (
Situation Assessment
), relations be-
tween defined entities are found. In the example
this refers to the
Is
relation between person and
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