Using Wireless Sensor Networks for Indoor Security Monitoring and

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Using Wireless Sensor Networks for Indoor Security Monitoring and Powered By Docstoc
					      Emergency Navigation
   by Wireless Sensor Networks
in 2D and 3D Indoor Environments


                          Yu-Chee Tseng
           Deptment of Computer Science
           National Chiao Tung University




                                            1
Outline
   Introduction
   System Overview
   Environment setting
   Regular report
   Emergency navigation service
   Simulation results
   Demonstration
   Conclusion


                                   2
Outline
   Introduction
   System Overview
   Environment setting
   Regular report
   Emergency navigation service
   Simulation results
   Demonstration
   Conclusion


                                   3
Introduction
   Wireless Sensor Network
       Each sensor has
           Limited Memory、Limited CPU、Wireless Transceiver、
            Sensing Unit
       Each sensor can
           Sense environments
           Communicate with others
           Do simple computations




                                                               4
Introduction
   Traditional Navigation Devices
       Advantage
           Cheap
           Easy deployment
       Disadvantage
           Fixed direction.
           Can not adapt to actual emergency situations.




                                                            5
Introduction
   Motivation
       According to the statistic report of the NFA of Taiwan(內政
        部消防署), 228 people died in fire accidents in 2003.
       The main reason is that people can not find “right”
        escaping paths to exits.
   Our Goal
       to develop an emergency navigation system
       for indoor 2D and 3D environments




                                                                    6
Outline
   Introduction
   System overview
   Environment setting
   Regular report
   Emergency navigation service
   Simulation results
   Demonstration
   Conclusion


                                   7
System Overview
        Our system is composed of 3 parts
           Environment setting
           Regular reporting
           Emergency Navigation
        Two network graphs
           Communication graph and guidance graph


                room           room                  room            room


         room           room                  room            room



    Communication graph                      Guidance graph
                                                                            8
Environment Setting
   Deploy sensors
   Construct reporting tree
   Setup initial navigation paths

                                     navigating




           reporting
                                                  9
Outline
   Introduction
   System overview
   Environment setting
   Regular report
   Emergency navigation service
   Simulation results
   Demonstration
   Conclusion


                                   10
Deployment of Sensors
   Plan locations of sensors
   Define the roles of sensors
     Sink

     Exit sensors

     Normal sensors

   Decide navigation links


          navigation
             links
         (for human)

                                  11
Construct a Reporting Tree
   Step 1. Discover symmetric links
       Each sensor periodically broadcasts HELLOs
       When receiving a HELLO, sensors reply ACKs
       After receiving an ACK, sensors record the sender ID in its
        link table


                                               HELLO
                                                                 2
                                                       ACK
                                    1    ACK       0


                                                   ACK       3
              Link table
        2 3                                                          12
Construct a reporting tree (cont.)
   Step 2. Construct a spanning tree
       Sink floods a BEACON.
       For a sensor receives a BEACON, it checks if the sender is
        in its link table
       If yes, it sends a REG(ister) to sink and rebroadcasts
        BEACON.
       Else, drops it                        BEACON



                                        REG

                               BEACON


                                                                 13
communication
      links
 (for packets)



                 14
Outline
   Introduction
   System overview
   Environment setting
   Regular report
   Emergency navigation service
   Simulation results
   Demonstration
   Conclusion


                                   15
Reporting Issues
   How often a report should be sent?
   Will each sensor report individually?
   Is there any inaccuracy?
   False alarm?
   How to save energy of sensors?




                                            16
Outline
   Introduction
   System overview
   Environment setting
   Regular report
   Emergency navigation in 2D environment
   Simulation results
   Demonstration
   Conclusion


                                             17
Design Principle
   When a sensor detects an emergency event, it
    forms a hazardous region

   The navigation algorithm will try to guide people as
    farther away from hazardous regions as possible




                                                           18
Problem Formulation
   Each sensor has an altitude.
   Sensors in hazardous regions will raise their
    altitudes.
   Each sensor guides people to the neighbor with the
    lowest altitude
   After forming hazardous regions, some sensors may
    become local minimum ones
       A partial link reversal operation is performed to solve this
        problem


                                                                       19
Phases of Navigation
   Initialization phase
       Initial phase is started by Exit sensor
       After this phase, every sensor has a default guiding
        direction.


   Navigation phase
       This phase starts by the sensor which detects an
        emergency event.




                                                               20
Terminology
   D:The radius of the hazardous region
   Aemg: A large constant which represents the
    maximum altitude
   Ai:The altitude of sensor i
   Ii:The altitude obtained in the initialization phase
   ej,i:The hop count from emergency sensor j to
    sensor i



                                                           21
Initialization phase
   Every exit sensor sets its altitude to 0 and broadcasts an
    initialization packet.
   When receiving an initialization packet, a sensor adds its hop
    count by 1.
   Then, it compares the hop count with its current altitude
                                                          Initial Packet
                                                   Sender ID Exit ID Hop Count

                           0       1       2
       Initial Packet          ∞
                               0       ∞       ∞
        0     0    0
                           3       4       5
                               ∞       ∞       ∞

                           6       7       8
                               ∞       ∞       ∞

                                                                                 22
Initialization phase (cont.)
    If the hop count is smaller than its altitude, it resets its altitude and
     setups its initial guiding direction to that sender.
    Then, it rebroadcasts this packet.


                                    Initial Packet
                                     1     0    1



                            0       1            2
          Initial Packet        0       ∞
                                        1            ∞
                                                     2
                                                         Initial Packet
           0     0 0                                      2     0    2
                            3       4            5
          Initial Packet        ∞
                                1       ∞
                                        2            ∞
                                                     3
                                                          Initial Packet
           3     0    1                                    5     0    3
                            6       7            8
                                ∞
                                2       ∞
                                        3            ∞
                                                     4

                                                                            23
Navigation phase

    When a sensor x detects an emergency, it will set its altitude to the
     maximum altitude Aemg (let it be 200).
    Then it broadcasts an emergency packet EMG(seq, x, x, Aemg, 0)
               EMG
      Seq   x   w     Aw   H

        seq:sequence number
        x:emergency ID
        w: sender ID
        Aw:altitude of sender
        h:hop count to emg. location
                                          23        24         25
                          EMG                  10        11         12
                      0 27 27 200 0
                                          26        27         28
                                               11        200
                                                         12         13

                                          29        30         31            24
                                               12        13         14
Navigation phase (cont.)
   When a sensor node y receives a EMG packet originated from
    node x, it will do the following steps.
     Step1:
         Decide that the emergency is a new one or not
             If it’s a new emergency, record this event and set the hop count ex,y to h+1.
             Else, compare the h and ex,y. If h is smaller than ex,y , set ex,y to h+1.
         Record the altitude (Aw) in the navigation link table.




                                                 23        24         25
                                                      10        11         12
                             Emg Table
                           EmgID    ex,y         26        27         28
                            27       1                11        200        13

                                                 29        30         31                 25
                                                      12        13         14
Navigation phase (cont.)
    Step 2:
        If eX,Y was changed in step1 and eX,Y ≦D, y considers itself
         within hazardous region. Then it re-calculates its altitude as
         follows:
                                                             
                                                  1          
                     Ay  max  Ay , Aemg                 Iy
                                             ex, y  1 
                                                        2
                              
                                                             



                              1   Safety Factor D:1   23        24         25
            Aemg                    I                   10        61
                                                                     11         12
                     e          
                                         Table
                                   2 Emg y
                       x, y    1EmgID       ex,y     26        27         28
                                    27        1            61
                                                           11        200        13
                                                                                63
                          1
            200                   11  61
                    1  1
                              2      ex,y < D ?       29        30         31        26
                                                           12        63
                                                                     13         14
Navigation phase (cont.)
    Step 3:
        If y has a local minimum altitude and it’s not an exit, it must adjust its altitude

                                                       
         as follows:                       1
                        Ay  STA( AN y )      min AN y  
                                           Ny

        AN y = altitudes of y’s neighbors
        STA = standard deviation
            A bigger value means closer to the hazardous region. So we need to adjust the
             altitude faster.
        |Ny| = number of neighbors of y.
            A smaller | Ny | means less escape ways. So we need to adjust the altitude faster.
        δis a small constant.

                                                    23        24         25
                Static adjustment                        10        61         12

                Five iterations
                                                    26        27         28              1
                Our scheme
                                                         61        200        63         63  0.1 
                                                                                      0Local minimum?63.1
                                                                                         2
                                                    29        30         31
                Three iterations                         12        63         14
                                                                               63.1
                                                                                                            27
Navigation phase (cont.)
    Step 4:
        y has to broadcast an EMG(seq, x, y, Ay, ex,y) packet if any of
         the following conditions matches.
            It’s a new emergency
            y has changes its altitude or ex,y in the previous steps.
    Step 5:
        If y is in hazardous regions and it sees an exit sensor which is
         in Ny and which is also in hazardous regions, then y chooses
         this exit sensor
        In all other cases, y directs users to a safer sensor first, and
         then gradually to a safe exit.


                                                                           28
Example—
Altitude after initial phase




                                                   S10
       Exit
                   1




                                              S7
                       4




                                         S4
                           7




                                    S1
                               10




  10x10 Grid Network
                                                         29
One emergency event –
after step 1, 2 & 4



                                       Local minimum




       1                               S10
           4                      S7
               7             S4

                   10   S1
                                                       30
One emergency event–
final result




       1                               S10
           4
                                  S7
               7             S4
                   10   S1
                                             31
Two emergency events–
after step 1, 2 & 4



                                                 Local minimum




       1
           4


                                            S9
               7                       S7
                                  S5



                   10
                             S3
                        S1




                                                                 32
Two emergency events–
final result




      1
          4
              7                            S9
                                      S7
                                 S5




                  10
                            S3
                       S1




                                                33
Outline
   Introduction
   System overview
   Environment setting
   Regular report
   Emergency navigation service
   Simulation results
   Demonstration
   Conclusion


                                   34
Simulation results
   We compare our navigation algorithm with
    “Distributed algorithm for guiding navigation across a
    sensor network” (MobiCom 03)
   This algorithm guides people to the nearest exits
       However, nearest exits may not be good choices




                                                             35
Simulation results
     Exit Emergency                   Hazardous region
        Method of Li et al.              Our method (D=2)
No
          Path
                               Pkt.
                                           Path
                                                             Pkt.      Case1. Our algorithm will choose
                              count                         count
                                                                        to pass hazardous region areas
                                                                        as farther away from emergency
1                             979                           252         locations as possible.
                                                                       Case2. Our algorithm will not
                                                                        guide people passing through
                                                                        the hazardous region.
2                             1254                          408        Case3. Only the sensors near
                                                                        the exit in the hazardous region
                                                                        will guide people to that exit.


3                       A     742                      A    137




                                                                                                      36
Outline
   Introduction
   System overview
   Environment setting
   Regular report
   Emergency navigation service
   Simulation results
   Demonstration
   Conclusion


                                   37
Demonstration
   System Components
       MICAz sensors
           Environment monitoring
           Navigation
           Sink
       MIB510 serial Gateway
           Gateway between wireless sensor network and PC
       PC
           Control Host




                                                             38
Demonstration                  second event
                                (emergency
                                   time)




                 first event
   exit         (emergency
 (normal            time)
  time)
                                              39
A Short Summary (2D)
   Novel indoor monitoring and navigation services based
    on wireless sensor network technolgoies
       emergency will raise sensors’ altitudes
       navigation similar to TORA protocol, but different in that
        emergencies will disturb altitudes
       altitude adjustment is designed for quicker convergence
       navigation in emergency applications requires safer paths, but
        not necessarily longer paths




                                                                         40
Emergency Navigation
in Indoor 3D Environments by
Wireless Sensor Networks


             Yu-Chee Tseng
     Department of Computer Science
      National Chiao Tung University




                                       41
 Introduction
    Why 2D guiding algorithms can’t directly apply to 3D environments


                                                      Rooftop
                room          room
3F
         room          room
                                        2F           room          room

                                              room          room

                room          room
2F
         room          room

                                        1F           room          room


                                              room          room
                room          room
1F
         room          room

                                                                          42
System Architecture
                                                                                       to rooftop
                                                                                (lemg, -(lIy+1))

          to rooftop
        (lemg, -(lIy+1))            (3, 2)     (3, 2)       (3, 1)          (3, 1)        D (3, 0)
                                  room                               room
                         (3, 1)     (3, 1)    A (3, 0)          (3, 1)        (3, 1)
                           room                          room
   4F        D
            (3, 0)      (3, 1)    (3, 1)     (3, 2)       (3, 2)

                                    (2, 2)     (2, 3)       (2, 2)          (2, 1)        A (2, 0)
                                  room                               room
                         (2, 1)     (2, 2)    B (2, 3)          (2, 2)        (2, 1)                                Control host
                           room                          room                                             Sink
   3F        A
            (2, 0)      (2, 1)    (2, 2)     (2, 1)       (2, 2)                                                     Controller
                                   (1, 2)      (1, 3)      (1, 2)           (1, 1)        A (1, 0)
                                  room                               room
                         (1, 1)     (1, 2)      (1, 3)       (1, 2)           (1, 1)
                                                                                                          exit sensor
                           room                          room
   2F                                                                                                     stair sensor
             A
            (1, 0)      (1, 1)    (1, 2)     (1, 3)       (1, 2)                                          normal sensor
                                                                                                          guidance direction
                                    (0, 2)     (0, 3)       (0, 2)          (0, 1)        C (0, 0)
                                  room                               room                            A:   floor gateway
                         (0, 1)     (0, 2)      (0, 1)          (0, 2)        (0, 1)                 B:   stair gateway
                       room                              room                                        C:   floor/stair gateway
   1F        C                      A                                                                D:   floor/roof gateway       43
           (0, 0)       (0, 1)    (0, 0)     (0, 1)       (0, 2)
Guidance initialization


                  (1, 1)
        2F
                          e
                (1, 0)        (1, 1)
                      d          f

                          (0, 0)       (0, 1)
                                            b
                   (0, 1)          (0, 2)
        1F
                          a
                (0, 2)         (0, 3)

                  c                             44
Guidance initialization           (3, 2)      (3, 2)       (3, 1)       (3, 1)        (3, 0)
                                 room                               room
                        (3, 1)     (3, 1)      (3, 0)       (3, 1)           (3, 1)
                         room                           room
       4F
            (3, 0)     (3, 1)    (3, 1)     (3, 2)        (3, 2)

                                  (2, 2)      (2, 3)       (2, 2)       (2, 1)        (2, 0)
                                 room                               room
                        (2, 1)     (2, 2)      (2, 3)       (2, 2)           (2, 1)
                         room                           room
       3F
            (2, 0)     (2, 1)    (2, 2)     (2, 1)        (2, 2)

                                  (1, 2)      (1, 3)       (1, 2)       (1, 1)        (1, 0)
                                 room                               room
                        (1, 1)     (1, 2)      (1, 3)       (1, 2)          (1, 1)
                         room                           room
       2F
            (1, 0)     (1, 1)    (1, 2)     (1, 3)        (1, 2)

                                  (0, 2)      (0, 3)       (0, 2)          (0, 1)     (0, 0)
                                 room                               room
                        (0, 1)     (0, 2)      (0, 1)       (0, 2)           (0, 1)
                     room                               room
       1F                                                                                      45
            (0, 0)     (0, 1)    (0, 0)     (0, 1)        (0, 2)
Principles of 3D guidance
   A sensor is located in a hazardous region if
       it is D hop away from the emergency point or
       it’s a stair sensor and its downstair sensor is in a
        hazardous region
   When guiding
       Avoid to guide people through hazardous regions
       Try to guide people to the exits on the ground floor
       Guide people to rooftop if there is no proper ways to
        downstairs



                                                                46
Simulation results
   4F    4F              4F           4F           4F       4F




   3F    3F              3F           3F           3F       3F




   2F    2F              2F           2F           2F       2F




   1F    1F              1F           1F           1F       1F




                                                                 47
              roof gateway    go upstairs   go downstairs
 Prototyping
      We have implemented our system using MICAz motes and
       MTS310 sensors on TinyOS.
      Protocol stack

 Application-
                               Network           Guidance                     GUI                    Guidance interface
  level UI      Deployment                                       Query
                             initialization    initialization


Users part
Sensors part

 Application          Tree                                               Guidance       Tree                                        Guidance
                                              Sensor task                                                 Sensor task
   layer          Reconstruction                                          service   Reconstruction                                   service



  Network         Symmetric link                 Tree                               Symmetric link          Tree
   layer            detection                 maintenance                             detection          maintenance
                             HELLO                      Report                EMG             HELLO                Report                 EMG

                               Physical layer and Data link layer                              Physical layer and Data link layer

                                               (a) Sink                                                   (b) Sensor

                                                                                                                                                48
JAVA GUI

                                                        Control
                                                         panel


    Building
   plan panel          stair     EMG



                                                         Monitor
                                       → 21 (in dec.)     panel
                       stair

                exit

                                            Current guidance direction


                       stair
                                                                         49
                               sink
Guidance UI




              50
Demonstration
                                           Control
                                            host
   Environment
       A virtual 2-store           Sink

        building


                                           Stair

                                                              Stair

                            Stair
                                                            Stair
                                           Exit

                                                            Exit

                              Exit

                                                                      51
                                                     Exit
Demonstration
   Vedio




                52
More Results

                                                                                      roof
3F
                                                                 roof



2F




1F



          Guidance pkt. count         151.8                  Guidance pkt. count         237.8                  Guidance pkt. count        78.8
     Tree Reconstruction pkt. count    7.6             Tree Reconstruction pkt. count        16.5         Tree Reconstruction pkt. count   4.8

                       (a)                                                (b)                                               (c)

                                              Stair sensor              Exit sensor                 Emergency




                                                                                                                                                  53
Conclusions
   Extending 2D navigation to 3D navigation

       on each floor, the navigation is similar to 2D

       stair and gateway sensors are paid of special attention

       roof is also paid of special attention




                                                                  54
References
   Q. Li, and et. al, “Distributed algorithm for guiding navigation
    across a sensor network”, MobiCom 03.
   Y.-C. Tseng, M.-S. Pan, and Y.-Y. Tsai, “A Distributed Emergency
    Navigation Algorithm for Wireless Sensor Networks”, IEEE
    Computers, Vol. 39, No. 7, July 2006, pp. 55-62.
   M.-S. Pan, C.-H. Tsai, and Y.-C. Tseng, “Emergency Guiding and
    Monitoring Applications in Indoor 3D Environments by Wireless
    Sensor Networks”, Int’l Journal of Sensor Networks, Vol. 1, Nos.
    1/2, pp. 2-10, 2006.




                                                                   55