When a node senses data, it will process the data and
advertise the data to others that are interested in it. If other users need to
access certain data, they make a query to the network, and whoever is holding
the data will pass it to them. However, the challenge is that the querying
node generally has no idea which sensor owns such data, and the sensing
node doesn??™t know which sensor will be interested in new data either. Thus,
many current researches focus on disseminating sensed information through
the network in a distributed and e?±cient way, which can guarantee the current
one to be captured quickly.
C. Object Tracking
Object tracking in a military battlefield situation is one of the most important
applications of WSNs. A sensor node deployed in a battlefield can
237 Chapter 10 Location Service, Info. Dissemination and Object Tracking
Dan-Dan Liu and Xiao-Hua Jia
detect vehicles or soldiers intruding into its sensing scope. It will generate a
reliable report, containing the location or ID of the intruder, and advertise to
the network through established routes and nodes. Individuals who need the
current location of certain vehicles or troops later can send a request to the
network and get proper information from sensor nodes inside the network. It
has strict requirements on energy consumption, since sensors are impossible
to recharge or replace during a battle.
Because of its flexibility, interrelated to energy e?±ciency as introduced
above, the quorum method can be considered as a good means to deal with
these three important problems in wireless sensor networks.
Pages:
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388