Real-Time Systems Laboratory Seolyoung, Jeong JADE (Java Agent DEvelopment framework )

Software development framework to develop multi-agent systems Comply with the FIPA standards for intelligent agents An asynchronous agent programming model Communication between agents either on the homogeneous or heterogeneous platforms Fully implemented in Java JADE overview (Java Agent DEvelopment framework)

European IST project that has developed the LEAP libraries JADE-LEAP : provide a run-time environment with reduced footprint and suitable for mobile lightweight Java environments on handheld devices JADE-LEAP runtime environment LEAP (Lightweight Extensible Agent Platform)

IEEE Computer Society standards organization, 1997 To facilitate the end-to-end interworking of intelligent agent systems Integration agent and other computer software Within the scope of FIPA –Agent Lifecycle Management –ACL(Agent Communication Language) –ACL Message Structure –Message Transport Service –White Page Service –Yellow Page Service –Inter-agent Interaction Protocols –Ontologies –Security FIPA (Foundation for Intelligent Physical Agents)

FIPA Agent Platform Agent Management System (AMS) –provides white-page and life-cycle service, maintaining a directory of agent identifiers (AID) and agent state. –Each agent must register with an AMS in order to get a valid AID. Directory Facilitator (DF) –the agent who provides the default yellow page service in the platform. Message Transport System (MTS) –the software component controlling all the exchange of messages –also called Agent Communication Channel (ACC) –supports the transport of FIPA ACL messages

JADE Architecture

Container: a running instance of the JADE running environment containing several agents –A single Main Container must always be active in a platform and all other containers register with it as soon as they start Main Container –AMS: Agent Management Service “White Pages” Maintains set of agents on a platform –DF: Directory Facilitator “Yellow Pages” Provides a service directory Maps service descriptions to Agent Identifiers Agents can add/modify/delete entries for themselves JADE Basic Concepts

Creating Agent –Extend the class jade.core.Agent and implement the setup( ) method –Identifiers –Termination –Passing arguments to an agent Internal Agent Architecture –Agent is a single-threaded Java program –Set of Behaviours –Scheduled by the Agent –Send/Receive messages through API Decoding/Encoding message content Agent Class

Each agent has a set of active behaviours Each behaviour should achieve a single task or sub-task –“Send this message” –“Buy X” Behaviours are Java objects Once behaviour is activated, it is run until it finishes Sequential and Parallel –Child behaviours are activated in order added. First behaviour is run until completed, then next and so on. Complex behaviour finishes when last child does. –All child behaviours are activated simultaneously Behavior can exit: When first child completes When all children complete Behaviour Class

Agent thread path of execution

Asynchronous message passing paradigm Each agent has mailbox where messages sent by other agent’s are posted Messages have a format specified by FIPA’s Agent Communication Language (ACL) –Fields: Sender, receiver, performatives, content, ontology, control (conversation-id, reply-with,..) Message implemented as an object of the jade.lang.acl.ACLMessage class that provides get and set methods for handling all fields of a message Agent Communication

Example : bookTrading - BookSellerAgent setup() Service Registration - Service Name - Service Type Add Behaviour

Example : bookTrading (simple multi-agent system) Seller1 Seller2 Buyer

Agent Management GUI

Main Container : Seller1

Buyer - waiting book1

Seller2 – add book1

Buyer – success buying book1

Thank you!