The Intrusion Detection in
Mobile Sensor Network
The Hong Kong University of Science and Technology
Gabriel Y. Keung , Bo Li , Qian Zhang
Reporter: 余志天
2011-5-18
Outline
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Introduction
Network and Mobility Model
The Intrusion Detection Problem in a MSN
Sensitivity Analysis
Simulation
Conclusions & Further Research
Outline
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Introduction
Network and Mobility Model
The Intrusion Detection Problem in a MSN
Sensitivity Analysis
Simulation
Conclusions & Further Research
Wireless Sensor Network(WSN)
 Consists of sensors for monitoring
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Temperature
Vibration
Pressure
Motion
Pollutants
Cooperatively pass their data through the network to a
main location.
Each sensor is connected to one or several sensors
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a radio transceiver
a microcontroller
an electronic circuit for interfacing with the sensors
an energy source.
Intrusion Detection in stationary WSN
Sensorsand
and identifying
 Detecting ground vibrations from foot steps
Cameras
warm body movement.

US The
Side operation of American Border Patrol
places sensors along the American/Mexican borders (“virtual fence")
Mexican
Side
k-Barrier Coverage(k-障碍覆盖)
 Barrier coverage
 treat sensor as barrier
 coverage: be detected by a sensor
 Detect any intruders along any paths by at
least k distinct sensors
A very important concept for intrusion detection
sensitivity analyze
Mobility Sensor Network(MSN)
 In stationary WSN
 sensors remain stationary after the initial deployment
 barrier coverage is determined by the initial network
configuration and sensor deployment
 vacuum zone
 In MSN
 sensors can be relocated after deployment
 a better barrier coverage
The objectives of this paper
 characterize the k-barrier coverage
 compute probability of k-barrier coverage
 investigate the probability of k-barrier coverage
sensitivity under different parameters
 examine the average travel distance
Outline
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Introduction
Network and Mobility Model
The Intrusion Detection Problem in a MSN
Sensitivity Analysis
Simulation
Conclusions & Further Research
The Kinetic Theory of Gas Molecules
 air molecule → mobile sensor
electron → intruder
A
B
 The mean free path
free path:AB,AC
 The average travel distance
derived from kinetic theory(the mean free path)
compute the probability of k-barrier coverage
performance
C
Scenario
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A: a long and narrow belt-like region;
N(A): the number of mobile sensors;
|A|: the area of the region; W: the width of the area; |A|/W: the length;
nA : the density of mobile sensors nA=N(A)/|A|
R:sensing range
the sensor location can be modeled by a stationary two-dimensional Poisson
process .
Mobility Model
Sensors move independently
Random direction mobility model
 Randomly chooses a direction θ ∈[0; 2π ) with probability density
function PΘ(θ)
 Randomly chooses a speed from a range vm ∈[0,vmax], with probability
density function PVm(vm)
 Once the boundary is reached, the sensor bounds back, by choosing
another angular direction and continues the process.
 Intruder movement is crossing from one parallel boundary to
another
 vi: the velocity of an intruder
Coverage Measurement
 k-barrier coverage for an
intruder traveling path
 k-barrier coverage for a
mobile sensor network
 Λ: the cumulative coverage
count by mobile sensors for
any intruder paths
 Pr(Λ≥k): probability that a
MSN satisfies this k-barrier
coverage definition
 uncovered distance
 coverage rate (Θ\ Θs\ Θv):
number of sensor coverage
per unit time
Outline
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Introduction
Network and Mobility Model
The Intrusion Detection Problem in a MSN
Sensitivity Analysis
Simulation
Conclusions & Further Research
What we need?
 Goal: Pr(Λ≥k)
Kinetic theory of gas molecules
 average travel distance
 λ: average uncovered distance
Pr(Λ≥k) can be achieved by formulating the uncovered
distance(λ) and sensor coverage rate(Θs)
First assume sensors are stationary
 cross section of coverage
 the number of sensor coverage
nA*|A|= Θs* τ
 average uncovered distance λ
travel distance of an intruder divided by the
number of sensor coverage
In mobile sensor network
Relative speed vrel
The coverage rate can be obtained by:
The k-Barrier Coverage in an MSN
 Probability of k-barrier coverage in an MSN:
 Average relative speed
 Expected total number of sensor coverage
Uncovered Distance Distribution
 the number of uncovered intruders: t = 0, N0; at time t, N
 during dt, the N*Θv*dt intruders will be covered
 l :uncovered distance for the length vi*t
Result Formulas
Outline
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Introduction
Network and Mobility Model
The Intrusion Detection Problem in a MSN
Sensitivity Analysis
Simulation
Conclusions & Further Research
Sensitivity analysis
 Density of Sensors and k-barrier Coverage
Probability(nA , Pr(Λ≥k))
 Simplify the equations for analysis
vi = vm
|A|=50×100, R=1
Sensitivity analysis
 In a hybrid sensor network
mobile : static = ρ
Sensitivity analysis
 Sensor Speed and k-barrier Coverage Probability
 vm : v i
Outline
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•
•
•
•
•
Introduction
Network and Mobility Model
The Intrusion Detection Problem in a MSN
Sensitivity Analysis
Simulation
Conclusions & Further Research
Simulation
Outline
•
•
•
•
•
•
Introduction
Network and Mobility Model
The Intrusion Detection Problem in a MSN
Sensitivity Analysis
Simulation
Conclusions & Further Research
Conclusions & Further Research
 Mobility can be exploited to obtain better
barrier coverage
 Further Research
detection error under varying sensor speeds
study the optimal patrol route of controlled
mobile sensors
Thank You!
Any questions?
Yu Zhitian
2011-5-18