1. Research Topics in Software and Reasoning Systems Bharat Jayaraman University at Buffalo (SUNY) Jan Chomicki, University at Buffalo Venu Govindaraju, University at Buffalo Kishore Ramachandran, Georgia Tech Luke Ziarek, University at Buffalo CSE Research Overview Collaborators: Fall 2014

2. Three Current Topics 1. Unobtrusive Smart Spaces 2. Modeling Complex Systems 3. Dynamic Analysis & Visualization CSE Research OverviewFall 2014 Research Methodology: - Start with Theoretical Foundations - Develop Practical Models/Languages - Implement, Apply, Learn, Improve

3. 1. Unobtrusive Smart Spaces CSE Research OverviewFall 2014

4. Research Topics 1. Large Camera Networks 2. Distributed State Transition System 3. Practical Deployment and Experiments 4. Smart Space Analytics CSE Research OverviewFall 2014 Three R’s of Cyber-Physical Spaces, V. Menon, B. Jayaraman, V. Govindaraju IEEE Computer, 44(9): 73-89, 2011 A Distributed Framework for Spatio-Temporal Analysis on Large-scale Camera Networks, K Hong, M Voelz, V Govindaraju, B Jayaraman, U Ramachandran, Proc. Distributed Computing Systems Workshops (ICDCSW), 2013

5. 2. Modeling Complex Systems Grand Challenge in Information Systems (www.cra.org)www.cra.org ….…. CSE Research Overview Fall 2014 “We need a mathematical model that relates the global behavior of complex systems to the local behaviors and interaction patterns of the individual elements … Whatever form such a model takes, it must permit us to define and control emergent behavior using declarative, not imperative, techniques.” Motivating Domains: Engineering, Biological, … Common Features: Complex Assembly, Laws of Behavior, Visualization

6. Constrained Objects Constraints: “The load on a wall ≤ its load bearing capacity.” “The sum of the forces at a joint should be zero.” etc.

7. class joint { attributes bar [ ] Bars; load [ ] Loads; constraints (sum X in Bars : X.B.F * sin(X.A)) + (sum L in Loads : L.F * sin(L.A)) = 0; (sum Y in Bars : Y.B.F * cos(Y.A)) + (sum M in Loads : M.F * cos(M.A)) = 0; constructor joint(B1, L1) { Bars = B1; Loads = L1; } } Load Sum of Forces = 0

8. Translation to Efficient Low-level Representations Inconsistency Detection and Failure Analysis Visualization for Dynamic Behavior From Constrained Objects to Constraint- based Design Research Topics Modeling Engineering Structures with Constrained Objects, B. Jayaraman and P. Tambay, Proc. Practical Aspects of Declarative Languages, Lecture Notes in Computer Science (2257), pp. 28-46, 2002 Compositional semantics for diagrams using constrained objects, B. Jayaraman, P. Tambay, Proc. Diagrammatic Representation and Inference, pp. 94-96, 2003

9. Towards Better Program Comprehension Run-time Visualization, Query-based Debugging Execution Analysis, Summarization JIVE: Java Interactive Visualization Environment Extensions for Real-time, Concurrency, etc. 3. Dynamic Analysis & Visualization Temporal Data Model for Program Debugging. D. Lessa, B. Jayaraman, J. Chomicki, Proc. Database Programming Languages, 2011. JI. FI: Visual Test and Debug Queries for Hard Real ‐ Time, E. Blanton, D. Lessa, P. Arora, L. Ziarek, B. Jayaraman, Concurrency and Computation: Practice and Experience, 2013.

10. Source Code Static – Behavior Obscure

11. JIVE Interface Source Code Enhanced Object Diagram Sequence Diagram Processes Query Result

12. JIVE Visualization: Objects as Environments JIVE object diagram showing objects as well as method activations in the object contexts CSE Research OverviewFall 2014

13. JIVE Objects: Detailed View JIVE object diagram showing internal details of objects and method activations Fall 2014 CSE Research Overview

14. Objects as Environments: Call-Path View JIVE object diagram focusing on the calling path, or the call stack. Fall 2014 CSE Research Overview

15. Flexible Views CSE Research OverviewFall 2014

16. Viewing Execution History: Multi-Threaded Programming CSE Research Overview Fall 2014

17. Visualization clarifies Program Behavior F1F2F3F4F5 P1 P2 P3 P4 P5 JIVE sequence diagram clarifies thread interactions Fall 2014 CSE Research Overview

18. F1F2F3F4F5 P1 P2 P3 P4 P5 JIVE sequence diagram at point of deadlock Fall 2014

19. CSE Research Overview Java Path Finder is a special JVM that explores all possible choices in scheduling with the goal of identifying a concurrency bug, such as deadlock, if one exists. The output of JPF is also an execution sequence that can be input to JIVE, which not only shows the tree of possible scheduling choices, but also the path leading to the error. Concurrency Bug Analysis: JIVE + Java Path Finder 10/8/2015

20. Android Workshop Coupling with Java Path Finder

21. 10/8/2015CSE Research Review

22. 10/8/2015CSE Research Overview

23. 3. Query Based Debugging Traditional debugging is more like “web browsing” – you have to manually look for the error. QBD is more akin to “web searching”, e.g.: - show all changes to a variable - when did a variable become negative - when was an invariant violated - when did concurrent update occur - show all contended monitors - show all priority inversion Common queries can be form-based, but custom queries are necessary. CSE Research OverviewFall 2014

24. Form-based Query Interface CSE Research Overview When was ‘value’ assigned to an int less than 100? Fall 2014

25. Query Result CSE Research OverviewFall 2014

26. JIVE’s Overall Architecture CSE Research Overview Fall 2014

27. Eclipse/JIVE Two-Process Model CSE Research Overview Fall 2014

28. J IVE does not represent program states directly, but infers (and reconstructs) states from events that occur. Important Property of JIVE – 1 CSE Research Overview Fall 2014

29. CSE Research Overview Fall 2014 Queries and Visualization work in a synergistic way: Queries help focus on what is of interest. Visualization provides a canvas on which to report answers to queries. Important Property of JIVE – 2

30. JIVE Demo www.cse.buffalo.edu/jive CSE Research Overview Fall 2014

31. CSE Research Overview Scalable Visualizations: Vertical Compaction Fall 2014 compactify

32. Execution Summarization: From Sequence to State Diagrams (View 1) CSE Research Overview Fall 2014

33. CSE Research Overview Fall 2014 From Sequence to State Diagrams (View 2)

34. Summary and Conclusions JIVE has useful features not found in modern IDEs: visualizing object states and execution history; query-based debugging; dynamic slicing; reverse stepping Declarative Queries and Visualization work in a synergistic manner to provide an effective run- time environment for OO Languages. JIVE can be used for teaching and learning, and also has features for understanding and debugging in industrial setting. CSE Research Overview Fall 2014

35. Further Work Fall 2014CSE Research Overview Incorporate full Temporal Queries and State Diagram construction into JIVE interface. Verification through Testing: the database approach to debugging facilitates analysis over multiple runs, checking invariants, etc. Model Checking in JIVE: The State Diagram resembles a Kripke Structure, and we can perform model-checking of such structures with respect to temporal-logic formula.