1. 1 Refining Reliability Estimation of Mobile Software Systems The International Workshop on Software Architectures and Mobility, ICSE-SAM 2008, Leipzig, Germany Sam Malek Department of Computer Science George Mason University Roshanak Roshandel Department of Computer Science & Software Engineering Seattle University

2. 2 Motivation Programming-in-the-small-and-many (Prism) –Challenges The role of software architecture in building dependable systems –Structure –Behavior –Style –Tools

3. 3 Architectural Reliability Modeling Focus –Predictive model for software quality –Quantitative analysis of architectural design decisions Our past work –Reliability prediction of software components –Reliability prediction of software systems Challenges –Uncertainties Information sources –What about connectors? Connectors are not specifically addressed in reliability approaches

4. 4 Mobility: A Different Set of Challenges Dynamic Structure Dynamic Interactions and Interaction Protocols Network Connectivity Issues …

5. 5 A Proposal We have a static reliability prediction of the system: –Components reliabilities –A model of components interactions in one specific structural/behavioral setting –A prediction of the system’s reliability in this setting We want: –Runtime monitoring of the system’s interactions at runtime and/or data obtained from prototype simulation [information source] –Use an architectural reliability modeling approach to refine the above reliability prediction

6. 6 Component Reliability Prediction L. Cheung, R. Roshandel, N. Medvidovic, L. Golubchik, Early Prediction of Software Component Reliability, ICSE 2008

7. 7 “Static” System Reliability Prediction R. Roshandel, N. Medvidovic, L. Golubchik, A Bayesian Model for Predicting Reliability of Software Systems at the Architectural Level, QoSA 2007.

8. 8 The New Piece… Runtime Monitoring of prototype and/or system –Explicitly identifying connectors and interactions among components and connectors –Gather data Refine the reliability model and parameterize it for connectors –Apply coupling, cohesion, clustering, centrality and other graph-based algorithms to model connections Apply an architectural reliability methodology to obtain a more accurate reliability analysis

9. Reflection and Monitoring – Prism-MW

10. Putting it all together 10

11. Questions?