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An Infrastructure for Agent Collaboration in Open Environments. Kenichi Yoshimura, Lin Padgham, and Wei Liu RMIT University Presented to Agents VIC May 2003. Agentcities Project. and

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An infrastructure for agent collaboration in open environments

An Infrastructure for Agent Collaboration in Open Environments

Kenichi Yoshimura, Lin Padgham, and Wei Liu

RMIT University

Presented to Agents VIC May 2003

Agentcities project
Agentcities Project Environments and

  • “Agentcities is a worldwide initiative designed to help realise the commercial and research potential of agent based applications by constructing a worldwide, open network of platforms hosting diverse agent based services. The ultimate aim is to enable the dynamic, intelligent and autonomous composition of services to achieve user and business goals, thereby creating compound services to address changing needs.”, from

  • A working network of agent-based services based on Foundation for Intelligent Physical Agents (FIPA) standards.

Motivations Environments

  • Agentcities: approaching 100 nodes connected, offering diverse services. But are services easily accessible to create composite services?

Standards for Open Environments (FIPA, WSDL)

Agent Communication Languages (FIPA ACL, KQML)

Ontology Representations (DAML+OIL, OWL)

Content Languages (FIPA SL, KIF)

Open Environment

Service Description and Discovery (DAML+S, UDDI)

Interaction Protocols

Reliability and Robust Issues

What s askit a gent s ervice k omposition i nterface t ool
What’s ASKIT? Environments(Agent Service Komposition Interface Tool)

  • A demonstration system.

  • Encourage development of complex services using existing services with the minimum effort.

  • A tool that enables people with limited programming experience compose customised services as easy as browsing information on the Internet.

  • No knowledge of open environments required.

  • Viewing a composite service as a loose form of teamwork.

  • The use of a goal directed BDI framework and study suitability of an existing model of teamwork for open environments.

What does it do
What does it do? Environments

Service types and associated interfaces.

Eg. bank service with open account, get balance and transfer money interfaces.

ASKIT Interface

Team plan

Customised Service

Open Environment like Agentcities

Team of user agents

An example scenario
An Example Scenario Environments

User Agent

Hi-Fi Agent

CD Agent

Power Supply

Get quote


Order CD

CD Delivery

Power supply unit booking

Booking confirmation

Order Hi Fi

Hi Fi Delivery

Composite service and teamwork
Composite Service and Teamwork Environments

  • Execution of composite services involves collaboration of heterogenous agents.

  • Similar characteristics desirable such as parallel execution and synchronisation of activities.

  • Observation of commitments between a user agent and service provider agents - however, traditional models of teamwork are typically too restrictive in open environments.

  • Implementation issues:

    • Failure management (eg. request being rejected)

    • Interaction with unreliable services (eg. services disappearing)

    • Service discovery

    • Interaction protocols and content languages

    • Message delivery and failure recovery

A current model of teamwork
A Current Model of Teamwork Environments

  • JACK Teams – hierarchical structure of teams.

  • Team plans to specify:

    • Member selection.

    • Coordination of team’s activities separately from individuals.

  • Roles to capture abstract capabilities.

  • Transparently implements basic requirements of teams – Eg. failure notification.

Coordination Team

Team Plan

Team members

Survey of jack teams

Provides a framework to model organisations with hierarchies.

Support of the BDI architecture with teams.

Easy specification of coordinated activities.

Good separation of team activities and individual activities.

Designed for closed environments.

Works only with instances of JACK Teams agents.

Eg. team plans rely on basic agreements of team members – success/failure report.

Survey of JACK Teams

Mapping teams to services
Mapping Teams to Services hierarchies.

  • Roles and service types

    • Both captures abstract capabilities of an entity.

  • Represent a composite service as a team plan.

    • Recycling existing facilities such as parallel execution and synchronisation.

    • Abstractly describe requirements by roles (i.e. service types).

  • Proxy agents: additional layer mapping JACK Teams to services in open environments.

    • Making unreliable services consistent from the team’s view – a represented services being unavailable, failures in interactions, and monitoring time-out for network related failures.

    • Managing interaction protocols and content languages.

Dynamic service discovery
Dynamic Service Discovery hierarchies.

  • Possible to have several instances of the same type of service available simultaneously in open environments.

  • In ASKIT, a service is modelled as service type and its associated interfaces.

  • Specify composite services using service types and their interfaces – this enables dynamic discovery of service instances depending on the current configuration of the environment.

  • Service discovery issues: FIPA’s Directory Facilitators (DFs) and Universal Description, Discovery and Integration (UDDI).

Extending team plans
Extending Team Plans hierarchies.

  • BDI architectures enable recovery from failures by selecting different plans that achieves the same goal.

  • Establish() method allows dynamic sub-teams selection from a list of potential agents (role containers).

  • When a team plan fails, why not re-execute with a different combination of agents?

    • Potentially avoids computational redundancies.

    • Additional level of backtracking.

Static dependency analysis

HF = Hi Fi Agent hierarchies.

CD = CD Agent

PS = Power Supply Agent

quote = HF.get_quote();

cd =;

psu = PS.order(quote, office);

unit =;

Requires 3 types (HF, CD, PS).

1 and 4 are performed by the same agent.

2 is independent.

3 depend on 1 because it requires a Hi-Fi model (quote).

Static Dependency Analysis

An example scenario1
An Example Scenario hierarchies.

User Agent

Hi-FI Agent

CD Agent

Power Supply

Get quote





Order CD

CD Delivery


Power supply unit booking


Booking confirmation


Order Hi Fi


Hi Fi Delivery


An example scenario2
An Example Scenario hierarchies.

User Agent

Hi-FI Agent

CD Agent

Power Supply

Get quote




Order CD



CD Delivery

Power supply unit booking



Booking confirmation

Order Hi Fi



Hi Fi Delivery

Putting all together
Putting All Together... hierarchies.

User Interface

Service Discovery

Composite Service Team

End User’s Agent

Backtracking Plan

Library of Plans

Role Assignment

User Specified Composite Service

Proxy Agent

Proxy Agent

Proxy Agent

Issues and future work
Issues and Future Work hierarchies.

  • How to represent services so that we can automate the proxy agents generation?

  • Analysis of input/output dependencies enough? How about preconditions and consequences?

  • What’s the right level of commitments of team members in open environments? Our approach too simple??

Resources hierarchies.

  • ASKIT is unreliably available at

  • FIPA JACK – a plugin for JACK Intelligent Agents for FIPA standard compliancy

Acknowledgement hierarchies.

  • ASKIT project associates: Antony Iorio, Richard Jones, David Shepherdson, Andrew Lucas, Ralph Rönnquist and Jeff Schultz.

  • Thanks to James Harland, Michael Winikoff, and Ian Mathieson for useful discussion and feedbacks!