Virtual Enterprise over COBMAF: A CORBA based

Multi Agent Framework

Anoop Srivastava, TIFR, Mumbai, India. Nupur Giri, Karan Kamdar, Sujeet G., Ashay K., Rahul I.

VESIT, Mumbai, India.

Index• Objectives

• Virtual Enterprise

• Multi Agent System

• COBMAF : CORBA based multi-Agent Framework

• VAME: Virtual Automobile Manufacturing Enterprise using COMBMAF

• Future Scope

• Conclusive Remarks

Objectives

• Design a framework to support Multi Agent system which offers heterogeneity of agents at language, platform and semantic level.

• Provide Application Programming Interfaces (APIs) to the Application developer to develop application over the framework.

• Develop message passing and lower level primitives for agent communication in a heterogeneous environment using CORBA .

• Outline agent interaction scenarios for local and global agent communication. Develop performatives for these agent interaction.

• Finally to demonstrate above framework for development of a Virtual Enterprise. (Virtual Automobile Manufacturing Enterprise)

Virtual Enterprise“A VE can be defined as a goal oriented constellation of (semi) autonomous distributed entities. Each entity, an organization and/or individual, attempts to maximize its own profits as well as contribute to defining and achieving the overall goals of the VE”.

• VEs are not rigid organizational structure within rigid frameworks but rather than heterogeneous ensembles, continuously evolving over time.

• VEs are formed to achieve a particular set of goals and have a shorter span of life than a traditional enterprise.

• There is no centralized control. Cooperation, Coordination and negotiation are the key features amongst the entities of VEs.

Multi-Agent Systems (MAS)

• The VE is composed of distributed and autonomous components, as in MAS.• Coordination, Competition and distributed problem solving are also problems of MAS.• VE formation and selection of partners and distribute task modeling market characteristics and negotiation is well researched topic in MAS.• MAS is a flexible modeling paradigm, which can model changes in partners and their roles etc.• Autonomy and cooperation are balanced effectively in MAS.

“Loosely coupled network of problem solver (agents) which interact to solve problems which are beyond individual capabilities or knowledge.”

• Mapping of VE to MAS:

COBMAF Architecture

• The Application Layer

• The Framework Layer

• The Message Transport Layer

COBMAF Framework Layer• COBMAF API

• Agents

• Multi-Agent Communication

• Local Agent Management System (LAMS)

• Global Agent Management System (GAMS)

• Facilitator agents

COBMAF Agent• Agent class extends threads.

• Every agent can utilize the sleep/awake, wait/notify states of the thread.

Agent(String, String ,String ,String)void addBehaviour(SimpleBehaviour)void addBehaviour(LooperBehaviour)void addBehaviour(CyclicBehaviour)void addBehaviour(WakerBehaviour)void addBehaviour(OneShotBehaviour)void sendACLMessage(ACLMessage)ACLMessage recvACLMessage()void startAgent()

The Agent Behaviors

• Simple Behavior: till done() returns false

• Looper Behavior: till the specified no. of time

• Waker Behavior: sleeps till the specified amount of time

• Cyclic Behavior: till the life of the agent

• One Shot Behavior: only once

•Behaviourabstract void action()

•SimpleBehaviourabstract void action()abstract boolean done()

•LooperBehaviourLooperBehaviour(int) abstract void action()

•Waker Behaviour()WakerBehaviour(int)abstract void action()

•CyclicBehaviorabstract void action()

•OneShotBehaviourabstract void action()

A Behaviour provides the agent a separate thread of control to execute a certain set of actions in a certain manner.

Multi-Agent Communication

• REGISTER• UNREGISTER• ACK• INFORM• INFORM_PROD• QUERY• FINAL• QUOTE

• ACL Message Class Sender ID, Receiver ID , Content, Performative

• UPDATE• ASKALL• REPLYALL• ASKONE• CONFIRMPRICE• CHECKORDER• CONFIRMORDER• ADVERTISE

• Performatives for any VE

• ACL Message API ACLMessage(String)void setContent(String)String getContent()addReceiver(String)

Local Agent Management System(LAMS)

• LAMS handles registration and authorization of all agents belonging to local host.

• LAMS contacts Facilitator Agents to make use of the Naming Service offered by CORBA.

• Also it makes use of Interface Repository of CORBA to register the services offered by this agent to local as well as external hosts.

• It sends an “Update” of new agent to all the other already registered agents.

• LAMS also registers it self with the GAMS.

• Application Level Agents : to be used by the VE application level agents

• Middleware Level Agents : to be used by the agents within the framework

Facilitator agents

• Communication Agent• Gatekeeper Agent

• Directory Service Agent• Naming Service Agent• Database Service Agent

Application level Facilitator AgentsDirectory Service Agent • The “Directory service” is used by the GAMS to register the services provided

by the Application level agents to agents of other hosts.• The “Interface Repository” and “Implementation Repository” of CORBA

contains the interfaces/service provided and parameters used to invoke agents.

Naming Service Agent: • ORBs Naming Service allows LAMS to associate an agent in the naming

context in the namespace.• The agent binds itself to the namespace in the ORB. Thus establishing a

unique identity.

Database Agent:• Proposed, but not implemented.

Communication Agent • This agent keeps track of the physical location of the agent through “CORBA Location Service”. All the application level facilitator agents internally use middleware level facilitator agents for communication.

Gatekeeper agent • Needed for communication with entities behind firewall and having various security features.• Proposed , not implemented

Middleware level Agents

Global AMS

• The Global AMS functions much like the local AMS except that it works on an inter organization scale keeping information about the participating organizations through their LAMS.

• It uses “Directory Service Agent” and “Communication Agent”.

•GAMS is hosted by a single organization/host of the VE, but is owned by the entire VE.

• If the organization hosting the GAMS wants to leave, election process is used to select the next organization.

• Osagent (smart agent) of CORBA can be used for this agent migration.

Virtual Automobiles manufacturing Enterprise :VAME

• RMA(Resource management agent)

• Sales Agent

• Procurement Agent

• Scheduler Agent

The VAME is an agglomeration of all companies that provide essential parts in the manufacturing of an automobile.

VAME AgentsResource Management Agent• Keeps track of Quantity of various products (inventory) and informs this status to scheduler agent.• Keeps track of various spare parts/ raw material required for manufacturing each product.• It is also responsible of initiating procurement agent in case the quantity of the raw material falls below a threshold.

Sales / Procurement Agents• RMA “pushes” information to sales agent which intern advertises these to LAMS and GMAS.• These agents use negotiation capabilities to negotiate best buying/selling price or time of delivery for the product. The parameters are user dependent.

Scheduler Agent• This agent is used to keep track of the task configuration of each ready product and no. of days it would take to manufacture using PERT/CPM technique.

Registration of Agents

Local Agent Discovery & Interaction

Local agent Discovery • Uniqueness of an Agent is taken care by LAMS.• The “Update’ send by LAMS to all the agents which are already registered with the LAMS allows discovery of agents.

Local Agent Interaction • When a product is being sold by Sales agent The Sales Agent interacts with RMA for “inventory/stock status” which intern

interacts with scheduler agent to find “order completion time” to complete the negotiations.

• When a product has to be Manufactured:RMA interacts with local Procurement Agent in case threshold of a product is low.

GAMS Interaction and Negotiation

Few Screen Shots

GAMS registers LAMS1 and LAMS2

Local agent interaction with encrypted Performatives

LAMS1 after registration of RMA, SA, ShA and PA

User interface for RMA

Extension

The work presented describes COBMAF-V1. The enhancements to which will be in the direction of:

• Building Self Learning, Mobile agents.• Integrating Ontology.• Developing COBMAF-Web Model.• Developing wrappers to deal with Legacy Systems……

Conclusive Remarks

• VE presents many challenges and opportunities for AI technology in direction information retrieval, message synchronization and communication, coordination and negotiation etc.

• Satisfying diverse user needs calls for advanced interfaces, user modeling and other emerging techniques.

THANK YOU