Unifying MAS MetaModels ADELFE, Gaia

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Unifying MAS Meta-Models ADELFE, Gaia PASSI

• Carole Bernon, Massimo Cossentino, Marie-Pierre
  Gleizes, Paola Turci and Franco Zambonelli

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Agent-Oriented vs. Object-Oriented

• Design a system ? Instantiate a meta-model
• OO context - design rely on a common denominator
• Universally accepted concept of object and
  related meta-model of object-oriented systems
• AO context - to date, no common denominator
• Each methodology has its own concepts and system
  structure

In the agent world the meta-model is the
critical element when applying the method
engineering paradigm
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Reasons to Unify

• Meta-model means to unify concepts
• Unique meta-model, a way of unifying the
  different concepts
• Helping designer to build a meta-model depending
  on the system he needs
• Choice of useful elements
• From the omni-comprehensive MAS meta-model
• Composition of process
• Method fragment selection phase
• Model coherence checking by CASE tools
• Unification eases model transformation

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MAS Meta-Model for ADELFE

• no predefined organization
• local goal
• cooperative
• detect and remove NCS

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Gaia Methodology

• First version
• Designed to handle small-scale, closed
  agent-based systems
• Modelled agents, roles, interactions
• Missed in modelling explicitly the social aspects
  of a MAS
• Official extension of Gaia
• Thought for open agent systems
• Focused on the social organization of the system

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MAS Meta-Model for Gaia
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MAS Meta-Model for PASSI
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Towards a Unifying MAS Meta-Model

• In order to define a unifying meta-model we will
  consider the following specific aspects
• Agent structure
• Agent interactions
• Agent society and organizational structure
• Agent implementation

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Agent Structure

• ADELFE cooperative agents

• Gaia and PASSI composition of roles

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Agent Structure - Considerations

• None imposes a specific classical agent
  architecture
• Seen as some kind of low level architectures that
  can be adopted during MAS implementation
• None explicitly deals with goals and plans
• ADELFE
• Notion of goal is only used to determine skills
• Plans are built at run-time by the system
• Gaia
• The concept of goal is implicit in roles
• Plans play no explicit role
• PASSI
• Goals are considered as non functional
  requirements
• Plans are modelled as algorithms (activity
  diagrams)

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Agent Interactions

• No relevant differences

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Agent Interactions

• No relevant differences

• ADELFE agents can communicate indirectly using
  environment
• Gaia communication mediated by the environment
  seen as a side effect

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Agent Interactions

• No relevant differences

• ADELFE agents can communicate indirectly using
  environment
• Gaia communication mediated by the environment
  seen as a side effect

• ADELFE ontologies have not to be modelled
  agents are able to adapt to the environment and
  other agents

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Agent Society and Organizational Structure

• ADELFE no predefined organization

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Agent Society and Organizational Structure

• ADELFE no predefined organization

• Gaia organization primary abstraction
• PASSI services and scenarios

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Agent Implementation

• ADELFE
• The problem of the system implementation has not
  been treated yet no platform has been imposed
• Gaia
• Totally abstract from implementation
• PASSI
• FIPA compliant systems
• Direct map among the most important elements of
  the model and their implementation

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Proposal for a Unifying Meta-model
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Conclusion

• Societies with or without predefined
  organizations (open systems)
• Generic agent (cooperative or not)
• Follows organizational or cooperation rules
• Possibility of identifying three domains
• Improvements an agent has a representation of
  the environment expressed via an ontological
  model
• Step towards a unique meta-model
• A unifying framework for the systems produced
  with different approaches

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Open Questions

• Can a unique meta-model exist?
• What description level has to be reached?
• How may designers choose meta-model elements?
• What kind of tools may ease their work?