Linking the calculus and BMethod

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Linking the -calculus and B-Method

• Damien Karkinsky
• PhD Symposium
• IFM 2005

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Motivation

• Distributed Systems display
• high degree of component autonomy,
• instantiation state encapsulation,
• dynamic reconfiguration.
• The pcalculus interaction model seen as suitable
  abstraction for such application domains.
• The B-Method offers separation of concerns when
  describing state components and a tool.
• Common semantics between the two might offer a
  powerful formal framework.

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Background

• Differences between the two methods are
• actions are non-atomic, operations are atomic,
• p has operational semantics, B denotational
  semantics.
• The conventional approach in the research field
  is to give B operational semantics by
• encoding each TERM of B with a TERM of p,
• proving that the encoding is sound and complete
  with respect to DB using bi-simulation.

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Methodology

• If a common semantics exists how would the
  MACHINE construct behave in a system of agents?
• We use B denotational semantics to derive a
  labelled transition system LTSM.
• LTSM is then extended and a wrapper is provided
  enabling interaction with p-agents.
• The design of the wrapper
• provides machine instantiation,
• separates operations into non-atomic actions.

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Methodology (cont.)
y

• In the case of machines without I/O no guards

val1
val2
P1
P2
INTER
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Methodology (cont.)
val1
P1
INTER
val1
P1
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Example
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Example (cont.)
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Using the wrapper

• The process can be used in a
  system of p-agents.

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A problem
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Future Work

• We are interested in investigating controlled
  interactions between p-agents and machine
  instances.
• Verification of divergence freedom properties
• The full p-calculus is too open,
• Machine communication internalised,
• Bi-simulation does not distinguish divergence.