Difference between revisions of "D32 Scalability"

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==== Qualitative Reasoning ====
 
==== Qualitative Reasoning ====
Probability is used in many distributed systems for breaking the symmetry between different components/processes, e.g. IEEE 1394 Firewire protocol <ref name="ieee1394"/>. For such systems, termination cannot be guaranteed for certain. Instead, a slightly weaker property is mostly appropriate: ''termination with probability one''
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Probability is used in many distributed systems for breaking the symmetry between different components/processes, e.g. IEEE 1394 Firewire protocol <ref name="ieee1394"/>. For such systems, termination cannot be guaranteed for certain. Instead, a slightly weaker property is mostly appropriate: ''termination with probability one''. As an example for this type of systems is to consider tossing a coin until it comes up tail. Provided that the coin is fair (in that sense that no face is ignored forever), eventually, the coin will eventually come up head.
  
 
=== Choices/Decisions ===
 
=== Choices/Decisions ===

Revision as of 12:15, 1 December 2010

Overview

Regarding scalability of the Rodin platform, the following contributions has been made:

  • (Alexei) Flow plug-in
  • (Alexei) Group Refinement
  • (Alexei) Modes
  • Emre Yilmaz and Thai Son Hoang (ETH Zurich) has developed a plug-in for supporting an extension of Event-B with qualitative reasoning. The extension allows developer to declare an event converges probabilistically (with probability 1). This is in contrast with standard certain termination, where convergent events must decrease the declared variant. Providing that the variant is bounded above, an event probabilistically converges if it might decrease the variant. The extension enables Event-B to model systems with almost certain termination properties, e.g. IEEE 1394 Firewire protocol[1] or Rabin's Choice Coordination algorithm.

Motivations

Flow plug-in

(Alexei)

Group Refinement

(Alexei)

Modes

(Alexei)

Qualitative Reasoning

Probability is used in many distributed systems for breaking the symmetry between different components/processes, e.g. IEEE 1394 Firewire protocol [1]. For such systems, termination cannot be guaranteed for certain. Instead, a slightly weaker property is mostly appropriate: termination with probability one. As an example for this type of systems is to consider tossing a coin until it comes up tail. Provided that the coin is fair (in that sense that no face is ignored forever), eventually, the coin will eventually come up head.

Choices/Decisions

Flow plug-in

(Alexei)

Group Refinement

(Alexei)

Modes

(Alexei)

Qualitative Reasoning

Available Documentation

  • Master thesis of Emre Yilmaz on developing tool support for qualitative reasoning in Event-B [2].
  • The development of Rabin's Choice Coordination Algorithm is available at the DEPLOY Repository [3].
  • A paper describing the development of Rabin Choice Coordination algorithm and tool support in the Proceedings of AVoCS'10 [4].

Planning

Flow plug-in

(Alexei)

Group Refinement

(Alexei)

Modes

(Alexei)

Qualitative Reasoning

References