The Intrusion Detection in Mobile Sensor Network

1. 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

2. Outline • Introduction • Network and Mobility Model • The Intrusion Detection Problem in a MSN • Sensitivity Analysis • Simulation • Conclusions & Further Research

3. Outline • Introduction • Network and Mobility Model • The Intrusion Detection Problem in a MSN • Sensitivity Analysis • Simulation • Conclusions & Further Research

4. Wireless Sensor Network(WSN) • Consists of sensors for monitoring • 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 • a radio transceiver • a microcontroller • an electronic circuit for interfacing with the sensors • an energy source.

5. Intrusion Detection in stationary WSN Sensors and Cameras • Detecting ground vibrations from foot steps and identifying warm body movement. Mexican Side • The operation of American Border Patrol • places sensors along the American/Mexican borders (“virtual fence") US Side

6. 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

7. 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

8. 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

9. Outline • Introduction • Network and Mobility Model • The Intrusion Detection Problem in a MSN • Sensitivity Analysis • Simulation • Conclusions & Further Research

10. The Kinetic Theory of Gas Molecules • air molecule → mobile sensor electron → intruder • 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 B A C

11. Scenario • 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 .

12. 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

13. 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

14. Outline • Introduction • Network and Mobility Model • The Intrusion Detection Problem in a MSN • Sensitivity Analysis • Simulation • Conclusions & Further Research

15. 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)

16. 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

17. In mobile sensor network • Relative speed vrel • The coverage rate can be obtained by:

18. The k-Barrier Coverage in an MSN • Probability of k-barrier coverage in an MSN:

19. Average relative speed • Expected total number of sensor coverage

20. Uncovered Distance Distribution • the number of uncovered intruders: t = 0, N0; at time t, N • during dt, the N*Θv*dtintruders will be covered • l :uncovered distance for the length vi*t

21. Result Formulas

22. Outline • Introduction • Network and Mobility Model • The Intrusion Detection Problem in a MSN • Sensitivity Analysis • Simulation • Conclusions & Further Research

23. 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

24. Sensitivity analysis • In a hybrid sensor network • mobile : static = ρ

25. Sensitivity analysis • Sensor Speed and k-barrier Coverage Probability • vm : vi

26. Outline • Introduction • Network and Mobility Model • The Intrusion Detection Problem in a MSN • Sensitivity Analysis • Simulation • Conclusions & Further Research

27. Simulation

28. Outline • Introduction • Network and Mobility Model • The Intrusion Detection Problem in a MSN • Sensitivity Analysis • Simulation • Conclusions & Further Research

29. 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

30. Thank You! Any questions? Yu Zhitian 2011-5-18