Safety Enhancing Mechanisms for Pervasive Computing Systems in Intelligent Environments

1. Hen-I Yang and Abdelsalam Helal Pervasive and Mobile Computing Lab University of Florida www.icta.ufl.edu Perware 2008, Hong Kong, March 21, 2008 Safety Enhancing Mechanisms for Pervasive Computing Systems in Intelligent Environments

2. Gator Tech Smart House And Our Panelists PerWare 2008, Hong Kong, March 21, 2008

3. Conflicts on Shared Resource Usage • Shard resources • No reliable monitoring and arbitration • Services unaware of others’ operations on share resources • Proper coordination needed Energy Saving Svc Lighting Service PerWare 2008, Hong Kong, March 21, 2008

4. Invalid operations 3500°F !! • Predefined range and conditions of operations for each device • The cues, hints and visual feedbacks fall to deaf ears when operated by systems • Invalid operations need to be monitored and prevented PerWare 2008, Hong Kong, March 21, 2008

5. Conflicting Side Effects Hey, Who Turns Off The Light? • Side effects exist • Impossible to account for all possible interferences from environmental effects • Non-determinant behaviors PerWare 2008, Hong Kong, March 21, 2008

6. Non-user-centric Behaviors • Difficulties in interpreting or predicting users’ behaviors and intentions • Pervasive computing systems are to assist, not dictate users’ daily life PerWare 2008, Hong Kong, March 21, 2008

7. Outline • Scenarios and Risk Analysis • Introduction • Four fundamental Elements of Pervasive Computing Systems • Safety Mechanisms • Effectiveness of the Proposed Mechanisms PerWare 2008, Hong Kong, March 21, 2008

8. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Goals Total safety guarantee is impossible • Accidents happen • People make mistakes • Murphy’s Law Attainable goals: • Do no harm • Handle safety risks • Proactively detect, prevent and manage the inherent safety risks PerWare 2008, Hong Kong, March 21, 2008

9. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Challenges • Dynamicity • Heterogeneity • Complexity • Uncertainty PerWare 2008, Hong Kong, March 21, 2008

10. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Strategy • Divide and conquer • Explicit modeling and description • Multilayered safety mechanisms • Avoidance, detection and handling PerWare 2008, Hong Kong, March 21, 2008

11. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Existing Safety Mechanisms • Physical safety • Typical computer and network system safety measures • Authentication • Access Control • Security • Privacy • Reliability enhancements PerWare 2008, Hong Kong, March 21, 2008

12. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Four Fundamental Elements • Device • Service • User • Space Space Service User Device PerWare 2008, Hong Kong, March 21, 2008

13. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Safety – Device • Device Description File • Operational Range • Allowable Frequency • PowerDown Sequence • Operational Parameter Checker • Frequency Checker (of Instruction Reception) • Invocating Service Identification PerWare 2008, Hong Kong, March 21, 2008

14. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Safety – Service • PowerDown Sequence • Event-driven programming paradigm • Bind • Align • Terminate • Explicit Service Interface • Explicit Dependency Description PerWare 2008, Hong Kong, March 21, 2008

15. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Safety – User • User Profile (Static) • Service Alignment • User Specified Context Interpretation • Impermissible Context Specification • User Profile (Dynamic) • Impermissible Context Detection PerWare 2008, Hong Kong, March 21, 2008

16. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Safety – Space • Emergency Detector/Context Graph • Space specific preferred and impermissible contexts • Impermissible context detection PerWare 2008, Hong Kong, March 21, 2008

17. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Static Safety Mechanisms • State Machine and Service Safety Interface • Mandatory Power Down Sequence • Prioritize Methods PerWare 2008, Hong Kong, March 21, 2008

18. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Static Safety Mechanisms PerWare 2008, Hong Kong, March 21, 2008

19. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Priority Safety API interface serviceSafetyMechanism() { boolean onInstantiated(obj); boolean onBinded(obj); boolean onAligned(obj); boolean onExecutionReady(); boolean onEmergencyPowerDown(); boolean bind(obj[] devices); boolean align(obj[] userPref); boolean execute(obj); } PerWare 2008, Hong Kong, March 21, 2008

20. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Dynamic Safety Mechanisms • Device Safety Checker • Context Manager and Emergency Detector • Emergency Handler Vector (EHV) • Service Registry PerWare 2008, Hong Kong, March 21, 2008

21. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Dynamic Safety Mechanisms PerWare 2008, Hong Kong, March 21, 2008

22. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Effective Safety Protections • Initialization • PowerDown mandatory for any new device/service • Deposit PowerDown emergency handler to EHV • Register with service registry • Specification of impermissible contexts PerWare 2008, Hong Kong, March 21, 2008

23. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Effective Safety Protections • Runtime • Screen for invalid commands/parameters to devices • Services have to be binded and aligned before exec • Occurrences of safety risks would trigger emergency handler • Impermissible contexts detection • Report change of status • Prioritized methods PerWare 2008, Hong Kong, March 21, 2008

24. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Discussion • Program/compile time versus runtime • Systems are only as safe as programmers can imagine them to be • Evaluation of safety in intelligent environments PerWare 2008, Hong Kong, March 21, 2008

25. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Conclusion Safety: “the condition of being safe from undergoing or causing hurt, injury or loss” – Merriam-Webster • For pervasive computing systems, safety is as important a consideration as effectiveness or usability • Proposed static and dynamic safety mechanisms offer implementation and runtime protections. • In face of dynamicity, complexity, heterogeneity and uncertainty, systems are broken down into fundamental elements: devices, services, users and space , each with its safety mechanisms. PerWare 2008, Hong Kong, March 21, 2008

26. Scenarios Introduction Four Elements Safety Mechanism Effectiveness Ongoing Research Activities • Safety-oriented programming model for pervasive computing • System authoring aids to implement safe systems • Evaluation methodology and framework PerWare 2008, Hong Kong, March 21, 2008

27. Questions? Thank you And Keep Safe PerWare 2008, Hong Kong, March 21, 2008