Alternately, the data report
249 Chapter 10 Location Service, Info. Dissemination and Object Tracking
Dan-Dan Liu and Xiao-Hua Jia
Fig. 7. Quorum method vs Match-making method.
can be saved locally waiting for queries from other nodes [39]. On the other
hand, soldiers need the up-to-date location information of other tanks or soldiers
from time to time. They should send their request to the appropriate
sensors that can provide desired information or initiate detection as soon as
possible. Note that moving objects are free to traverse around within a large
area. Such a tracking requires non-local collaboration among sensors. It can
reduce the bandwidth consumption thus preserve the energy e?±ciency, and
alleviate the risk of individual node/link failures. In addition, adding negotiation
before integral data transmission helps reduce redundant and duplicate
data dissemination. Therefore, object tracking combines the problems existing
in location service and information dissemination and can be dealt with
by similar methods.
4.1 Traditional Protocols
If we apply traditional methods to object tracking, some similar deficiencies
appear as in location service and information dissemination. For example under
SPIN [23] or Directed Di?®usion [24], all nodes in the network (i.e. n) are
required to participate in data accessing. This is very costly especially when
the frequency of event occurrence and interest is not equivalent.
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