1. Self Adaptive Software
An Architecture-Based Approach to Self-Adaptive Software
- Peyman Oreizy, Michael M. Gorlick, Richard N. Taylor, Dennis Heimbigner, Gregory Johnson, Nenad Medvidovic, Alex Quilici,David S. Rosenblum, and Alexander L. Wolf
Presenter : Viral Mehta

2. Self Adaptive Software
“Software that modifies its behavior in response to changes in its operating environment – end user input ,external hardware device and sensors”
Eg: Fleet of unmanned air vehicles.

3. Adaptation and Embedded systems
Continuously running Applications
Changes in Environment
paint of a room.
network traffic.
Can Serve multiple purpose by changing behavior

4. Issues for adaptation What Conditions? Open or Closed adaptation
Type of autonomy
Frequency
Cost Effectiveness
Information Type and Accuracy

5. Spectrum of self - adaptability

6. Software Adaptation in the Large
Developing a compressive adaptation methodology that spans adaptation in the small to adaptation in the large, and then develop the technology that support the entire range of adaptations.

7. Software Adaptation in the Large
Life Cycle
Change app. s/w.

8. Evolution Management (lower wheel)
Process by which changes are applied, controlled and verified.
Entities / Phases:
Dynamic software Architectures
C2 / Weaves
Maintaining consistency and system integrity
Architecture evolution manager
Enacting changes
Editors / Interpreter

9. Dynamic software Architectures - C2
Components are arranged in a hierarchy
Service requested form above components
Notifications to components below
Flexible Components - do not share a common address space / common thread of control

10. Dynamic software Architectures - Weaves
Object flow centric architecture
Object as input – object as output
Blind communication

11. Similarities Weaves / C2 (help adaptation)
Distinguishes between components and connectors
Neither places restriction on granularity of components
Asynchronous communication

12. Maintaining consistency and System integrity
Ongoing adaptations continuously threatens system safety, reliability and correctness
Strict correspondence between the architectural model and the executing implementation required.
Architecture evolution manager (AEM)
changes – single / Transaction
Maintains consistency between the architectural model and implementation as changes are applied
Prevents changes from violating architectural constraints.
eg. Each component has to be connected to a connector

13. Enacting Changes Architecture editor Design Editor
Used to construct architecture and describe modification. Eg. Visio
Design Editor
critiques as arch is built – prevent semantic errors / ensure min amount of safety
Modification interpreter
to interpret change scripts

14. Adaptation Management (upper wheel)
Describes the life cycle of adaptive software systems
Monitors and evaluates the application and its operating environment
Plans adaptation
Deploys change description to running application

15. Collecting observations
Embedded assertions (inline observers)
resource shortage ,violation of low level constrained
Expectation agent
responds to the occurrence of event pattern
Surrounding events
Availability of network connection
Human observers

16. Evaluation and monitoring
Inconsistencies can occur when some architectural element behaves in a manner inconsistent with the required behavior or when an elements assumption about its environment becomes invalid
Static analysis
Attributed graph grammar
Dynamic analysis
runtime checks using observers

17. Planning changes Adaptation Planning Observation planning
Determines which observations are necessary for deciding when and where adaptations are required.
Takes in to account environmental assumptions, expected behaviors, availability of observers, and their costs
Adaptation Planning
Determines which adaptations to make and when
For faster reaction : Predefined solution framework

18. Deploying change description
Change agents
Propagate among various sites to make required changes
carry with them the new components / connectors
coordinated changes at multiple sites

19. Thank you…. Questions ? Comments?