1. Mo Liu 1, Elke A. Rundensteiner 1, Dan Dougherty 1, Chetan Gupta 2, Song Wang 2, Ismail Ari 3, and Abhay Mehta 2 1 Worcester Polytechnic Institute, USA 2 HP Labs, USA 3 Ozyegin University, Turkey BIRTE2010 Singapore NEEL: The Nested Complex Event Language for Real-Time Event Analytics Acknowledgements: This work is partly supported by HP Innovations Award, NSF 1018443 and NSF IIS 0917017, Turkish National Science Foundation TUBITAK under career award 109E194. We thank Di Wang, Han Wang and Richard T. Ellison III for the case study.

2. 2 Event Processing Event Consumer Event Producer Event Processing—The Big Picture

3. Data Streams Query Results Data Sources Put on surgical gloves Wash your hands before touching next patients RFID Input Put on mask for H1N1 contagious patients Aggregate statistics for a hospital 3 RFID Input Hospital Disease and Hygiene Control Detect hygiene violations Track workers D. Wang, E. Rundensteiner, R. Ellison III, Active complex event processing: applications in realtime health care, VLDB (demonstration paper), 2010.

4. Primitive event instance is defined to be an occurrence of interest in time. Composite event instance occurs over an interval. Event history H is an ordered set of primitive event instances. CEP Basics e(t) time t e([t1, t2]) time t1 t2 4

5. Outline Event Processing NEEL Formal Semantics of NEEL E-Analytics System Case Study Conclusion

6. Compact Incremental Convenient 6 Why Nested Queries? + + + + +

7. NEEL: The Nested Complex Event Language Support nested SEQ, AND, OR with NEGATION Specify time period Specify condition on attributes Assume value-based comparison 7

8. NEEL Query Example Time 8

9. Nested Expression Variable Scope Inner query Outer query Time Nested sub-query 9 AND

10. Window Constraints w.ts time o.ts Sub Window: [w.ts, o.ts] 10

11. Predicate Specification Simple predicate Correlated predicate 11

12. Negation Time Positive component Negative component 12

13. Scoping of Negation r.ts time o.ts ! Washing [r.ts, o.ts] 13

14. Nested Negation is outputted if w time or 14 r1r1 w2w2 o 10 time r1r1 w2w2 o 10 time d8d8 s5s5 c9c9 No s or no c between w 2 and o 10 (s, c) exists between w 2 and o 10, d must exist between (s, c)

15. Predicates with Negation Condition: all events have the same id. Option 1: State condition in the outer SEQ Inner events s, d and c are not visible in the outer SEQ construct. 15

16. Predicates with Negation Condition: all events have the same id. Option 2: State condition in the inner SEQ Should the query return when no negative events exist? −Condition is evaluated to be false: No final output. However, no outer results should be filtered as no negative event exists. r1r1 w2w2 o 10 Id: 1 1 1 time Any P v s.id !=s.id is true 16 −Condition is evaluated to be true when involving negative events.

17. Our Proposal: Predicates with Negation is generated. 17 We split condition and state the predicates involving negative components directly with these negative components. Predicates only involving positive components are stated directly with these positive components. r1r1 w2w2 o 10 Id: 1 1 1 time The way we write predicates influences its meaning and results. The positive components are first evaluated. If negative components exist, we evaluate the negative predicates.

18. Predicates with Negation Example SEQ(Recycle r, ! SEQ(Washing w, ! Sharpening s, Disinfection d), Checking c, Operating o) Condition: all events have the same id. 18 SEQ(Recycle r, ! SEQ(Washing w, ! (Sharpening s, s.id = w.id ), Disinfection d, w.id = d.id = o.id ), Checking c, Operating o, r.id = c.id = o.id) | d.id | c.id| r.id

19. Outline Event Processing NEEL Formal Semantics of NEEL E-Analytics System Case Study Conclusion

20. Notations denotes an ordered sequence. denotes a set of event instances. denotes the cross product of event histories. denotes predicates on events 20

21. Formal Semantics of NEEL Window constrained event history Window constrained event history for the event type E i Union of event histories 21

22. Formal Semantics of NEEL SEQ operator SEQ operator with Negation 22

23. Formal Semantics of NEEL AND operator AND operator with Negation OR operator 23

24. Outline Event Processing NEEL Formal Semantics of NEEL E-Analytics System Case Study Conclusion

25. E-Analytics System Selective caching [DMSN] Algebraic operators: WinSeq WinOr, WinAnd Iterative execution strategy [DMSN] [DMSN] Processing Strategies for Nested Complex Sequence Pattern Queries over Event Streams, Mo Liu, Medhabi Ray, Elke A. Rundensteiner, Dan Dougherty, Chetan Gupta, Song Wang, and Abhay Mehta, DMSN 2010 25

26. Outline Event Processing CEP Basics NEEL Formal Semantics of NEEL E-Analytics System Case Study Related Work Conclusion

27. Case Study: Real-time Infection Control WPI and UMass Medical School project: Development and Testing of an Electronic Infection Control Reminder System for Healthcare Workers. Hospital Infection Control System (HICS) 27 D. Wang, E. Rundensteiner, R. Ellison III, Active complex event processing: applications in realtime health care, VLDB (demonstration paper), 2010.

28. Sample Queries 28

29. SNOOP: do not support scope SASE: only support flat queries Cayuga: apply SQL-like syntax SEL: focus on temporal relationships only ODE: not compact for sequence and negation [SASE] E. Wu, Y. Diao, and S. Rizvi, High-performance complex event processing over streams, SIGMOD, 2006, pp. 407-418. [SEL] D. Zhu and A.S. Sethi, SEL - A New Event Pattern Specification Language for Event Correlation, Proc. ICCCN-2001, Tenth International Conference on Computer Communications and Networks, Scottsdale, AZ (Oct. 2001), pp. 586-589. [ODE] Narain H. Gehani, H. V. Jagadish, Oded Shmueli: Composite Event Specification in Active Databases: Model & Implementation. VLDB 1992, pp. 327-338 Related Work [SNOOP] Sharma Chakravarthy, V. Krishnaprasad, etc, Composite events for active databases: semantics, contexts and detection. VLDB 1994, pp. 606-617 [Cayuga] A. J. Demers, J. Gehrke, B. Panda, M. Riedewald, V. Sharma, and W. M. White, Cayuga: A general purpose event monitoring system. in CIDR, 2007, pp. 412-422. 29

30. Conclusion Design NEEL composed of SEQ, NEGATION, AND, OR; Introduce the formal query semantics for NEEL; Study issues in NEEL for predicate, negation and etc; Design E-Analytics system; Conduct case study in health care 30

31. Thank You!