INTELLIGENT AUTOMATION INC.

Extending Rational Rose to support MAS design in UML

Intelligent Automation Inc.

2 Research Place, Suite 202

Rockville, MD 20850

http://www.i-a-i.com

presented by: Renato Levy

INTELLIGENT AUTOMATION INC.

Outline

• Introduction to IAI and its software tools

• Three-tier agent architecture

• Cybele

• Design of MAS using DIVA

• Problems and pitfalls

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Expertise

• Multi-agent Systems Design, Development and Simulation

• Distributed Computing• Scheduling and Logistics• Agent-based Distributed Control

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Software tools

• Cybele : Agent Infrastructure for distributed computing and inter-agent communication

• DIVA : A case tool with design document editing, online repository, runtime execution support service, verification and Cybele code generation

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Three Tier Architecture of IAI Agents

1- Role Layer:1- Role Layer: Describes the syntax and semantics of the roles this agent can perform in this application.

2- Adapter Objects:2- Adapter Objects: Makes the necessary translation between domain independent semantic of the role layer to the passive domain object expertise.

3- Domain Layer:3- Domain Layer: Represents the information content of an agent. Holds the domain expertise of the agent. Layer were existent legacy software can be easily reused.

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An Example of Role Interaction

Dutch Auction Art Buyer English Auction Art Buyer English Auction Car Buyer

Buyer

Buying Art

Adapter

BuyerBuyer

Adapter Adapter

Buying Art Buying Car

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Cybele : An Agent Infrastructure

• Provides location independent communication among agents with efficient flexible, dynamic multicasting

• Provides services for creating, migrating and terminating agents at run time

• Supports multi-threaded and shared-threaded

• Provides an activity model where an agent can work on multiple tasks concurrently

• Emphasis is on high-performance, scalability, flexibility and ease of use

• Current prototype of Cybele is implemented using the object-oriented paradigm with a Java API

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Cybele : Architecture Guidelines

• Cybele basics: Enforcement of the Activity-oriented programming interfaces or AOPI.

• Portability of users’ code: User-written agent code runs on any Cybele environment in which the needed services are available

• Reusability of users’ code: User’s code are re-usable even if services are modified

• Plug n play service: Encourage vendors to plug whatever service they desire into the Cybele to suite a particular platform

• Provision for addition of new services: Provide means for agent developers to add and access supplemental services without affecting the reusability and portability

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Cybele : Architecture

Distributed, Interactive Distributed, Interactive Computing Computing InfrastructureInfrastructure (DICI) (DICI)

Cybele KernelCybele KernelSupporting Supporting Three-tier architectureThree-tier architectureAnd AOPIAnd AOPI

Fundamental ServiceFundamental ServiceLayerLayer

Supplementary Supplementary Service LayerService Layer

Basic Service LayerBasic Service Layer

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DIVA

A design tool for agent based distributed system

Use an extension of UML as means for system description

Integrated with the industry leader Rational Rose 98i/2000e

Automatic code generation Maximize interaction and protocol

reusability Automatically generate

verification model from the same design document

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DIVA and Rose

Rose Extensibility Interface (REI)

•Model Semantics•Diagrams•Context Menus•Properties•Add-Ins

Add-In Registry

•Events•Stereotype files•Property files•Menu files•Data files

Rational Rose

Legend•Control •Data

Events•Rosescript•COM server

Stereotypes•Icons•String

Menus•Rosescript•External program

Extensible Properties•New tools/tabs•New properties

Rose Script•Code generation•Custom dialogs

•Shell•File I/O

•Web access•Environment

Add-In

COM Client/Server•Respond to events•Custom Spec Dialog

Java Bean /COM Server•Logic of Add-In•Choice of languages

Java ObjectsSource Files•Java Code•Promela Code

Java-COM Bridge

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Multi-agent System Design: Entities

• Physical entities of the System (MODEL)

• Agents

• Non-agent entities (such as databases, legacy classes)

• Protocols

•Roles

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Multi-agent System Design: Diagrams

Agents X MODEL -> Deployment Diagram

Agents X Hosts (distribution) -> Deployment Diagram

Agents X non-agent -> Class Diagrams

Agents X Protocols -> Class Diagram

Protocols X Roles -> Class Diagram

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Multi-agent System Design: Protocols

Protocols are defined as the description of a relation between two or more agents of the system. Any interaction between two agents are subject to a protocol ruling. The agents that play a part on the protocol perform according with the roles described on this protocol.

A protocol is described by a class diagram which depicts its roles and by a set of interaction diagrams which show the details of the exchange of information between such roles.

In Rational Rose®, protocols were created using stereotypes.

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Multi-agent System Design: Agents X Roles

In order to play a role on a protocol an agent has to adhere to an interface publicized by the role.

The interface required by the roles is automatically extracted by the DIVA case tool.

The agent implements the interface by means of delegation to non-agent object that conforms with the interface. (adapter objects)

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Multi-agent System Design: Role ClassesRoles are entities contained by protocols, that define the syntax of a protocol player.

Agents can play different roles on different protocols or even more than one role on the same protocol instance

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Role Design: State Diagram

Statename

entry: Delegate.EntryAction()entry: ^Recepient.M:OutgoingEventName(field1, field2)do: Delegate.DoAction()do: ^Recepient.M:OutgoingEventName(field1, field2)exit: Delegate.ExitAction()exit: ^Recepient.M:OutgoingEventName(Field1, field2)

IncomingEventName( field1, field2 )[ func() == const1 || var = const2 ] / Delegate.TransitionAction() ^Recepient.OutgoingEventName(field3, field4)

IncomingEventName( filed1, field2 )[ func() == const1 && var == const2 ] / Delegate.TransitionAction ^Recepient.OutgoingEvent(field3, field4)

A Role is defined by an enhanced state machine diagram, in which the information about the guard conditions and actions are detailed enough to extract the conversation syntax.

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Role Reusability

The correct extraction of the syntax of a conversation from the semantics and context that they carry is fundamental to provide role reusability across domains.

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DIVA: Interaction Protocol Verification

State Diagrams Of Roles and Sequence Diagrams of Interactions

Role and Adaptor Objects in Java

Concurrent Processes in PROMELA Script

Verified and Re-usable Roles and ProtocolsVerified and Re-usable Roles and Protocols

RoseScript, Java Bean/COM Server

PROMELA Translator

SPIN Tool

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Importing Protocols/Roles

DIVA’s repository allows validated protocols and roles to be shared and reused on several domains.

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Rose and UML pitfalls

• Rose is rather inconsistent on the way it can be extended by a third-party add-in. A variety of different techniques are needed to interface with Rose in order to accomplish the most simple tasks. (i.e. Rosescript, COM, ActiveX, Java beans, ….)

• Despite all the methods to interface with Rose there was no way to enhance its graphical output, forcing us to recreate some of the graphics on a separate child window.

• UML, as implemented in Rose, leaves too much room for free-form notes. In order to describe a complex system with less ambiguity, richer and more formal representation is needed.