Occasionally Connected Wireless Sensor Networks for Search and Rescue and Wildlife Monitoring

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??????????????????????? - Occasionally Connected
Wireless Sensor Networks for Search and Rescue
and Wildlife Monitoring

• ??? Jyh-How Huang
• ???????? ????? ?????
• Department of Computer Science
• University of Colorado at Boulder

2
????

• ????????????????
• Cenwits ??????
• ?????????????????
• ?????????????
• ??

3
??

• ??????Wireless Sensor Networks(WSNs)
• ?????????????,??CPU,???,??,???????????
• ??????????????????,???????????????????????
• ???????????Occasionally Connected Wireless Sensor
  Network(OCWSNs), Delay Tolerance Network(DTN)
• ?????????,??????????????????????????
• ????????????????
• ???? ?????, ????
• ???? ??????, ??????

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???? ???????????????
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Cenwits ??? ??????

• ?? ????????,??????????????????????
• ??,??,??
• ?????????,????
• ???????? ??????????????

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?????

• ?
• GPS????????? ?,??
• GPS???????????
• ????? ???????
• RFID ???? ?????????????

• ????????,??,?????

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??????

• ????,???????,??????
• ?,?(500??)
• ???????????
• ??????????
• ??(??5002000)
• ?????

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Cenwits ?????? (I)
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Cenwits ??????(II)
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Cenwits ??????(III)

• ???? 2359 ????? 6 ??

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??1 ????????????
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??? ????

• MICA2 sensors
• 900 MHz 4 KB SDRAM 128 KB flash and 4-512 KB
  EEPROM
• Mantis OS 0.9.1b ????
• MTS420CA GPS ???
• ??????????????
• ???????????????????????

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??2 ?????????? ??? 1 A ? B ??? 2
????????????? ??? 3 C ? B
?????????2??????
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???1?5?????,???6??????????????????????????6?????
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Cenwits ??? ???????????

• 20 ? 40 ????,???????????????????
• ??????????????,????(Wi-Fi Internet Access),???
• ??????????????????,????
• ????????WiMax??????
• ????????????,????????????,?????????????,?????????

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??? ??????????

• GPS ???,?,??,??????
• ????? ?,?
• ???????
• VHF/UHF ??radio???
• ?????
• ?? ?,?
• ???????????,????????????

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GPS ??????????

• ???????????50?
• ?????????????????????
• ??,?,???

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??? ??????????

• ??????????
• ??????????,??,?,????
• ???????????,??????????
• ?????????????,??????????????

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(No Transcript)
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???????????

• ?????? ??
• ????????
• ??,?,?
• ????,??????????????
• ?????????????????
• ????????

21
??

• ????????????
• ????????,????
• ??
• ???????
• ??
• ????????????
• ?????????????
• ??????????????????
• ??,????,????,??????????

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• ?
• http//csel.cs.colorado.edu/huang/Cenwits/index.h
  tm
• huangjh,mishras_at_colorado.edu

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Possible Problems

• Birds are fast, do we have enough time to
  transmit data?
• Robust protocol for half transmitted data
• When memory is full, how do we choose which
  records to overwrite?
• If we have more than one carriers, how do we
  prevent misunderstanding?

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(No Transcript)
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????? ? RFID ??
332617

• RFID ?????????ID???
• ?????? ?????
• ?????????
• ???? DoS ??
• ?????????????
• ????????????
• ???????
• ????????????

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Getting Info from AP
AP
a
Im AP Beacon AP Public Key Signed(Root CA)
IDAP_PKey Rnd AP_aSKey Mac(packet)AP_aMKey
Rnd 1 Dynamic ID Treadmill Table AP_aSKey
Mac(packet)AP_aMKey
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Getting the Key Table

• After verifying AP, the sensor node gets a keys
  list from AP, encrypted by symmetric key between
  them
• The table contains which key to use when running
  into node with dynamic ID x

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Getting the Weight Table
Weight Curve

• Give the new node n entries that is on the field
  already and n to come
• Dynamic IDs are assigned in inconsecutive order
• Most important(Possibly Missing) Nodes Set

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• Beacon This is node 10

• 8 Reply RndKey8_10 Mac(Packet)Key8_10

• Rnd1 Rnd2 Record Vector 10Key_8_10
  Mac(Packet)Key8_10

10
8

• Rnd21Key8_10
• Record Vector 8
• The list of what I want

• Here are the records that you need
• The list of what I want

There you go, records you want
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????

• ????
• ????????????????????
• ?????????????????????
• 10 feet/sec Beacon period 10 seconds
• 1 mile/hour Beacon period 1.7 minutes
• No beacons during night time
• Stay in receive or sleep mode depending on
  available power

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Future Plans for Cenwits

• Deployment in Yosemite NP summer 2006 with Shiv
  and Rick and Alberto
• Security Implementation and conference paper
  summer 2006 with Shiv and John
• Patent and larger scale experiment fall 2006
  with CU Tech Transfer Center

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Future Plans for WildSense

• Develop protocols for wildlife monitoring Fall
  2006 with Tom and Shiv
• Implement prototype and simulate the birds and
  mammals with UAVs and R/C tanks Winter 2006
  with Tom and Shiv and Rick and Aerospace
  department
• Tune the protocol and publish conference paper
  Spring 2007

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Current Loosely Coupled Systems

• ZebraNet
• At each scan for neighbors
• if node(I am) is within range of BS
• send data to BS and delete this data
• else send data to all neighbors

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Memory Management

• MAX RECORD COUNT
• Replace the old record with new one of the same
  node and keep the total records of a node less
  than MAX_RECORD_COUNT
• MAX HOP COUNT
• Dont forward a packet that has high probability
  of reaching AP already
• MIN RECORD GAP
• When 2 records are recorded in a time gap lt
  MIN_RECORD_GAP, replace the old one with new one.

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Exchanging Data Vectors Get only want you need

• Each node is given a range of record IDs it can
  use
• Whenever it fills up an empty record, it changes
  the index bit to 1
• e.g. fills up record 1 100001 gt 110001
• Two nodes exchange their record vectors and find
  out what they need from each other

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Why using timestamp from GPS is inefficient?

• There are 31536000 seconds in a year, needs 25
  bits to represent that