Defeasible Workflow, its Computation and Exception handling

1. Defeasible Workflow, its Computation and Exception handling ZongWei Luo, Amit Sheth, John Miller, Krys Kochut LSDIS Lab, Univ of Georgia Athens, GA 30602

2. Motivation Scenario - Transport of a Very Low Birth Weight Infant Georgia Ambulance Medical College of Georgia NICU Monitor the infant Rural area Exceptions Infection Respiratory Cardiac Disease In collaboration with Dr. Karp & Dr. Bhatia in MCG Suspect Review data Initial Assessment Diagnosis plan Definitive management plan Consultation Initial Data Consultation

3. Motivation • Facts about Clinical Decision Making *: • Clinical decision making is a process by which alternative strategies of care are considered and selected. • Decisions should be clear cut and error-free. • Human, environmental influences are frequently complex, uncertain and difficult to control. • The nursing and medical professions have expressed an interest in the precision and objectivity by which decisions are made, while simultaneously retaining an individualistic, holistic approach to patient management. • Standardization of management plans is usually accompanied by paying less attention to differences in patients’ needs. • Defeasible workflow is used to facilitate such a decision making. *Meier, P et al.; Clinical Decision Making in Neonatal Intensive Care,Grune & Stratton, Inc.

4. Defeasible Workflow • Default Modeling & Execution • common sense rules can be applied by default • Dynamic Resolution • conflicting interests and values & preference relations • Exception Handling • emphasis on experience Defeasible = Decision made based on original knowledge might not be valid in the future when more information is available; Defeasible workflow = here we use this approach to support adaptive workflow.

5. Default Modeling • JECA rules • ECA (Event, Condition and Action) • Justification • Provides necessary context, may be null when everything is certain • Example • Event: Risk factors ( ex.heart murmurs) • Condition: related to Cardiac Disease • Action: Initial Assessment • Justification: blood family member of opposite sex does not have Cardiac problem

6. Dynamic resolution • Evaluation Architecture • Clustered • Hierarchical • Dynamic resolution • Default value • Preference relationship Event: Risk factors ( ex.heart murmurs) Condition: related to Cardiac Disease Action: Initial Assessment Justification: home member of opposite sex has Cardiac problem Default value: home member of opposite sex does not has Cardiac problem

7. Exception handling- Design Exception initial T1 T2 execute System User retry prepare Ta failed done Response Timeout Omission initial Exception hierarchy execute prepare commit abort

8. A quick review of METEOR ORBWork run-time HOST 7 HOST 8 TASK TASK Manager HOST 1 TASK Scheduler TASK Scheduler HOST 9 TASK Scheduler TASK Scheduler TASK Scheduler HOST6 HOST 2 TASK Manager TASK Manager TASK TASK

9. Task Scheduler Managing Multiple Workflow Instances Monitor Recovery System Transition1 Data Objects Task AND Transition2 Scheduler Task Manager Task Manager Task Manager Task Manager ... Task Manager ... Task Manager Pending Done Task invocation Running Task Task

10. Handlers for well-understood exceptions Case-based Manual Exception handling- Runtime Competence based hierarchy: Workflow manager Scheduler Task Manger Task Realization

11. Current Status under development

12. Conclusion • Default modeling & dynamic resolution - good system design principle • Model evolution and structure changes - Decision made during exception handling • Case-based approach - learning from experience