1. When Security Games Go Green: Designing Defender Strategies to Prevent Poaching and Illegal Fishing Fei Fang 1, Peter Stone 2, Milind Tambe 1 University of Southern California 1 University of Texas at Austin 2

2. Green Security Domains: Protecting Fish and Wildlife Fishery Protection Wildlife Protection 2

3. In collaboration with Panthera A tropical forest in southeast asia Main focus: Tiger, Leopard Other animals: Tapir, Serow, Gaur, etc Green Security Domains: Understand the Problem In the Field 3

4. 8-hour patrol in April 2015 Green Security Domains: Understand the Problem In the Field 4

5. Security Games: Infrastructure Security vs Green Security Infrastructure security games Protecting infrastructure Single shot games Very limited number of attacks Lack significant data Highly strategic attackers Surveil/plan carefully 5 Green security games Protecting wildlife, fish etc Repeated games Repeated and frequent attacks Significant amounts data Attacker bounded rationality Limited surveillance/planning

6. Green Security Game A model for green security domains Generalize Stackelberg assumption Planning algorithms Designs defender strategy sequence Framework including planning and learning Learn parameters from attack data Contributions 6

7. Outline Background and Motivation Contributions Green Security Game Model Planning Planning and Learning Experimental Results Future Work and Conclusion 7

8. Green Security Game Model JanFebMarAprMay 0.30.40.10.20.500.10.7 0.2 0.3 0.40.50.60.1 0.60.70.10.20.30.200.9 0.40.50.60.30.10.20.30 0.10.20.30.40.50.30.40.1 0.30.40.5 0.1 0.2 0.3 0.40.5 0.1 0.60.30.40.20.4 8

9. Green Security Game Model JanFebMarAprMay 9

10. Attacker chooses target with bounded rationality Following the SUQR model Choose more promising targets with higher probability Evaluation on key properties Attackers have different characteristics (parameters) Green Security Game Model 10

11. Outline Background and Motivation Contributions Green Security Game Model Planning Planning and Learning Experimental Results Future Work and Conclusion 11

12. Planning JanFeb N80%20% S 80% 12

13. Planning x JanFebMarAprMay ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? 13

14. Solve greedily Consider current round utility only Ignore impact of current strategy in the future Planning x JanFebMarAprMay 00000000 00010000 00000000 00000000 00001000 00000000 00000000 00000000 14

15. Planning PlanAhead-M PlanAhead-M Look ahead M steps: find an optimal strategy for current round as if it is the M th last round of the game Sliding window of size M. Example with M=2 JanFebMarAprMay 15

16. Planning FixedSequence-M JanFebMarAprMay ABABA 16

17. Outline Background and Motivation Contributions Green Security Game Model Planning Planning and Learning Experimental Results Future Work and Conclusion 17

18. Learn parameters in attackers’ bounded rationality model from attack data Previous work Apply Maximum Likelihood Estimation (MLE) May lead to highly biased results Our learning algorithm Calculate posterior distribution for each data point Planning and Learning 18

19. Outline Background and Motivation Contributions Green Security Game Model Planning Planning and Learning Experimental Results Future Work and Conclusion 19

20. Experimental Results Planning Baseline: FS-1 (Stackelberg), PA-1 (Myopic) Attacker respond to last round strategy, 10 Targets, 4 Patrollers Baseline 20

21. Experimental Results Planning and Learning Baseline: Maximum Likelihood Estimation (MLE) Solution Quality Runtime 21

22. Outline Background and Motivation Contributions Green Security Game Model Planning Planning and Learning Experimental Results Future Work and Conclusion 22

23. Learn the parameters in convex combination from attack data Consider missing data (silent victims) Uncertainty in the model and robust strategies Real-world deployment (on-going) Trial test: November 2014 Extensive deployment: July 2015 Future Work 23

24. Green Security Game Planning is necessary with generalized Stackelberg assumption Learn attackers’ behavior model from data On-going real-world deployment Conclusion Thank you! feifang@usc.edu 24

25. Backup Slides 25

26. When Attackers’ Belief Getting Closer to Stackelberg Assumption 26

27. Attacker Memory = Two Rounds 27

28. Robustness of PA-M 28

29. How do rangers/poachers interact? A population of poachers Poachers lay snares, check/ relocate the snares frequently Rarely caught on site Rangers may find footprint/snares/ skulls of animals All the findings are entered into data system every month Green Security Domains: Protecting Fish and Wildlife 29

30. General Framework of Green Security Game Learn from data: Improve model Defender plans her strategy Local guards executes patrols Poachers attack targets Start New Round 30

31. Future Work 31