abstract

1

On the Design and Implementation of Open
Multi-Agent Systems
or
What Stands Between an Open MAS and a Mess
Naftaly Minsky Rutgers University
2
What is an Open MAS (Community)?

• Autonomy of member agents.
• Distribution.
• Heterogeneity.
• Dynamically changing membership.
• Mixed modus operandi collaboration and
  competition.

3
Examples of Open MASs

• A P2P community e.g., a collection of vendors
  and buyers over the internet.
• A virtual enterprise, i.e., a coalition of
  companies, forming a grid.
• Supply-chain systems.
• A dynamic team of buyers for a department store.
• In a sense, every large MAS, even if it starts as
  a closed system, opens up under the pressure
  of evolution.

4
Difficulties with Open MASs

• How does one interact with agents one knows
  little, if anything, aboutand whom one does not
  trust?
• How does one reason about such a system?
• How does one protect the system from buggy, or
  rogue, agents? Or from agents with a different
  agendas?
• Etc.

5
For Insight, Consider a Social analogy

• Examples of open social communities
• The set of cars moving on roads.
• A country.
• The key for organizing such communities are
  their global laws
• Traffic laws
• The constitution of a country

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Some Consequences of Global Laws

• They create regularities that engender
  predictabilityin spite of the openness of the
  communitythus simplifying the system.
• They can facilitate harmonious collaboration, and
  safe competition.
• They can establish an authority structure,
  allowing some agent to control others, and thus
  manage them.
• They can protect the community against ignorant,
  careless, or malicious, agents.

7
Characteristics of Effective Laws?

• They must be sparselike traffic laws, for
  example.
• Lest they would stifle the autonomy of agent
  (consider planned economies),
• and they would be too complex to reason about
  (consider tax laws).
• They need to be well established, lest they would
  be irrelevant.
• Laws can be established via education, customs,
  self interest, or by enforcement.

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Back to the Cyber World

• All the benefits of global laws are applicable
  to MASsif they can be established firmly
  enough.
• How does one establish a law over a MAS?
• By manual construction.
• By voluntary compliance
• If it is in the interest of everybody to obey
  this law.
• And if the violator cannot damage anybody but
  himself.
• By enforcement.
• Laws can be specified and enforced via the
  concept of law-governed interaction (LGI).
• Example, in this workshop laws that support
  management in open communities.

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The concept of Law-Governed Interaction (LGI)

• LGI is a message exchange mechanism that enables
  an open community to interact under an explicit
  and strictly enforced communal law.
• Salient characteristics of LGI
• The law deal only with the interaction between
  agents, treating the agents themselves as black
  boxes.
• A single MAS may have a multitude of interrelated
  laws.
• Law enforcement is entirely decentralizedfor
  scalability.
• LGI is currently prototyped by the Moses
  toolkitit is to be released soon.

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Proposed Methodologyfor Large MASs

• A critical step in the development of a MAS
  formulate an enactable law which is to govern
  itor an ensemble of such laws.
• This lawgiven that it has been establishedwould
  provide a framework in which the MAS is to be
  specified, designed, constructed, and maintained.
• Needed an interface between the following two
  complementary technologies
• A regulation mechanism, like LGI, for
  formulating and enforcing laws and
• A MAS development methodology like Gaia or
  Tropos.

11
Questions?