This document discusses adaptable transition systems, which are a formal model for self-adaptive systems. It defines an adaptable system as one that has distinguished control data that can be modified at runtime to change the system's behavior. An adaptable transition system augments a standard transition system with control propositions that represent this control data. Control data can be modified by an autonomous manager component to achieve adaptation. The interaction between a manager and managed component can be modeled using adaptable interface automata, which extend interface automata with control propositions. This formalism allows precise study of adaptation mechanisms.

1. Adaptable T ´´
ransition Systems
-- Roberto Bruni, UNIPI
-- Andrea Corradini, UNIPI
-- Fabio Gadducci, UNIPI
-- Alberto Lluch Lafuente, IMT
-- Andrea Vandin, IMT
ASCENS General and Working Meeting, Prague, February 11-14 2013

2. adap tation
is a game

3. OUTLINE
1 White box adaptation
“A Conceptual Framework for Adaptation” [FASE 2012]
2 Adaptable Transition Systems
“Adaptable Transition Systems” [WADT 2012]

4. OUTLINE
1 White box adaptation
“A Conceptual Framework for Adaptation” [FASE 2012]
2 Adaptable Transition Systems
“Adaptable Transition Systems” [WADT 2012]

5. What is
adaptation?

6. “... a software system self-adaptive if
changes behavior in response to ...”
[*] Oreizy, P., Gorlick, M.M., Taylor, R.N., Heimbigner, D., Johnson, G., Medvidovic, N.,
Quilici, A., Rosenblum, D.S., Wolf, A.L.: An architecture-based approach to self-
adaptive software. Intelligent Systems and their Applications 14(3), 54–62 (1999)
[*] Robertson, P., Shrobe, H.E., Laddaga, R.: Introduction to self-adaptive software:
Applications. In: Robertson, P., Shrobe, H.E., Laddaga, R. (eds.) IWSAS. LNCS, vol.
1936, pp. 1–5. Springer (2001)
[*] Self-Adaptive Software: Landscape and Research Challenges, Mazeiar Salehie,
Ladan Tahvildari, ACM Transactions on Autonomous and Adaptive Systems 4, 2.

7. Lotfi A. Zadeh,
Proc. IEEE, 1963

8. BLACK-BOX ADAPTATION

9. White box
adaptation

10. ADAPTATION MECHANISMS
constraints
contracts plans
aspects architectures
messages
contexts rules
configuration
variables policies programs
CONTROL DATA

11. WHAT IS AN ADAPTABLE SYSTEM?
CONTROL DATA OTHER DATA
ADAPTABLE SYSTEM
“adaptation is the run-time
modification of control data”

12. A SYSTEM IS...
“...adaptable if it has a distinguished control data
that can be modified at runtime.”
“...adaptive if its control data is modified at runtime
for some computation.”
“...self-adaptive if it modifies its own control data at
runtime.”

13. “an excellent discussion of
the precise meaning of the
term adaptive software.”
- Carlo Ghezzi, Evolution, Adaptation, and the
Quest for Incrementality, LNCS 7539/2012,

14. OUTLINE
1 White box adaptation
“A Conceptual Framework for Adaptation” [FASE 2012]
2 Adaptable Transition Systems
“Adaptable Transition Systems” [WADT 2012]

15. task? task?
D{}[] D{}[t] D{}[tt]
down! up! up!
task? task?
U{}[] U{}[t] U{}[tt]
schedule! schedule!
finish! finish!
U{t}[] U{t}[t]
task?

16. task? task?
D{}[] D{}[t] D{}[tt]
down! up! up!
task? task?
U{}[] U{}[t] U{}[tt]
schedule! schedule!
finish!
Is it s
finish!elf
U{t}[]
da
task?
pti v e?
U{t}[t]
a

17. task? task?
D{}[] D{}[t] D{}[tt]
down! up! up!
task? task?
U{}[] U{}[t] U{}[tt]
schedule! schedule!
finish! finish!
U{t}[] U{t}[t]
task?

18. task? task?
D{}[] D{}[t] D{}[tt]
down! up! up!
task? task?
U{}[] U{}[t] U{}[tt]
schedule! schedule!
finish! finish!
U{t}[] U{t}[t]
task?

19. task? task?
D{}[] D{}[t] D{}[tt]
ffer ent
di
down! up! up!
,140
= 4 U{}[t] task?ions!
B 8 task?
U{}[] at U{}[tt]
ret schedule!
int erp
schedule!
finish! finish!
U{t}[] U{t}[t]
task?

20. Interface Automata
in a nutshell

22. IA = Automata + Interface (i/o distinction)
task? task?
down! up! up!
task? task?
schedule! schedule!
finish! finish!
task

23. IA = Automata + Interface (i/o distinction)
task? task?
down! up! up!
task? task?
schedule! schedule!
finish! finish!
task?

25. task? task?
D {} [] [t] [tt]
schedule?
up! schedule! schedule!
down!
finish!
U {t}

26. task? task?
D {} [] [t] [tt]
schedule?
up! schedule! schedule!
down!
finish!
U {t}
task? task?
{}[] {}[t] {}[tt]
finish!
finish!
finish!
task? task?
{t}[] {t}[t] {t}[tt]

27. task? task?
D {} [] [t] [tt]
schedule?
up! schedule! schedule!
down!
finish!
U {t}
task? task?
{}[] {}[t] {}[tt]
schedule! schedule!
schedule?
finish!
finish!
finish!
task? task?
{t}[] {t}[t] {t}[tt]
schedule! schedule!

28. Adaptable
Interface
Automata

29. task? task?
down! up! up!
task? task?
schedule! schedule!
finish! finish!
task?
AIA = IA + control propositions (colors)

30. task? task?
down! up! up!
task? task?
schedule! schedule!
finish! finish!
task?
AIA = IA + control propositions (colors)

31. Exploiting
Control Data

32. AUTONOMIC MANAGER
Analyze Plan task? task?
D{}[] D{}[t] D{}[tt]
Knowledge Execute down! up! up!
Monitor
task? task?
U{}[] U{}[t] U{}[tt]
MANAGED COMPONENT schedule! schedule!
finish! finish!
U{t}[] U{t}[t]
task?

33. AUTONOMIC MANAGER
Analyze Plan task? task?
D{}[] D{}[t] D{}[tt]
Knowledge Execute down! up! up!
Monitor
task? task?
U{}[] U{}[t] U{}[tt]
MANAGED COMPONENT schedule! schedule!
finish! finish!
U{t}[] U{t}[t]
task?

34. some behavioural relation

35. normal output actions become inputs
(M “listens” outputs of B)

36. task? task?
D{}[] D{}[t] D{}[tt]
down! up! up!
task? task?
U{}[] U{}[t] U{}[tt]
schedule! schedule!
finish? finish!
U{t}[] U{t}[t]
task?

37. task? task?
D{}[] D{}[t] D{}[tt]
down! up! up!
task? task?
U{}[] U{}[t] U{}[tt]
schedule? schedule?
finish? finish?
U{t}[] U{t}[t]
task?

38. control output actions become inputs
(B “obeys” outputs of M)

39. task? task?
D{}[] D{}[t] D{}[tt]
down! up! up!
task? task?
U{}[] U{}[t] U{}[tt]
schedule! schedule!
finish! finish!
U{t}[] U{t}[t]
task?

40. task? task?
D{}[] D{}[t] D{}[tt]
down? up? up?
task? task?
U{}[] U{}[t] U{}[tt]
schedule! schedule!
finish! finish!
U{t}[] U{t}[t]
task?

41. ISO
(for deterministic AIA)

42. Beyond
Isomorphism

43. control output actions become inputs
(B “obeys” outputs of M)
collapse transitions labelled with B
(M “ignores” B-moves)

44. task? task?
D{}[] D{}[t] D{}[tt]
down! up! up!
task? task?
U{}[] U{}[t] U{}[tt]
schedule? schedule?
finish? finish?
U{t}[] U{t}[t]
task?

45. task? task?
D{}[] D{}[t] D{}[tt]
down! up! up!
task? task?
U{}[] U{}[t] U{}[tt]
finish? finish?

47. alternating simulation

48. (for deterministic IA)

49. Conclusion

50. OUTLINE
1 White box adaptation
“A Conceptual Framework for Adaptation” [FASE 2012]
2 Adaptable Transition Systems
“Adaptable Transition Systems” [WADT 2012]

51. adap tation
is a game

53. RECONCILING BLACK- AND WHITE-BOX ADAPTATION?
“in the game between the system and the environment,
the manager has a strategy to ensure the satisfaction of ψ.”
“receptiveness, realizability, and controllability
can be formulated as model-checking problems
for alternating-time formulas.”

54. THANKS!