Information Technology Reference
In-Depth Information
Table 4.4
Decentralized CMA tasks addressed in this topic and the respective decentralized move-
ment analysis principles used
Task
Reference
Principle
Mode
Space
Movement
pattern detection
Laube et al.
(
P6
.
2008
)
m.diffusion,
Moving nodes
Unconstrained
Movement
pattern detection
Laube et al.
(
P12
.
2011
)
m.compensation,
m.diffusion
Moving nodes
Unconstrained
Movement
pattern detection
Both et al.
(
P19
.
2013
)
m.compensation,
m.diffusion
Cordons
Network
Network load
Both et al.
(
P19
.
2013
)
m.diffusion
Cordons
Network
Clustering of
point clusters
Laube and
Duckham
(
P8
.
2009
)
m.compensation
Moving nodes
Unconstrained
Privacy-safe-
guarding in
LBS
Laube et al.
(
P11
.
2010
)
m.compensation,
m.privacy,
m.resilience
Moving nodes
Network
increase their spatial reach for sensing through collaboration with neighboring nodes.
When the nodes are mobile, however, they can compensate their limited spatial reach
simply through roaming and accumulating and integrating the gathered information.
4
Laube et al. (
P12
.
2011
) called this process “information grazing”. Even though
in this very example the gathered information was purely the position history of
the moving nodes, other applications could collect information about other spatial
variables, such as, for example, humidity or temperature. Node mobility, allowing
nodes to move about in space and time, allows for collecting and accumulating more
information than could be accessed through a spatially limited perception range alone.
It is important to note the a node can autonomously pursue mobility compensation,
whilst most following strategies require collaborating nodes (Table
4.4
).
4.3.2.2 Mobility Diffusion
Mobility diffusion is an important communication strategy in dynamic decentralized
spatial information systems.
Mobility diffusion
refers to the strategy that moving
nodes are allowed to physically move information around in the absence of connec-
tivity (Grossglauser and Tse
2002
; Grossglauser and Vetterli
2006
; Duckham
2012
).
Thus, for instance, in Laube et al. (
P6
.
2008
) roaming nodes hand over information
tokens allowing for a repeated evaluation of the group composition leading towards
the discovery of flock patterns. Knowledge is here “separated” from nodes, such that
knowledge is no longer limited by the limitations of the nodes. Similarly, Laube et al.
(
P12
.
2011
) explore a combination of mobility compensation and mobility diffusion.
4
Think of Pac-Man moving through his maze and eating away the pellets.
