Introduction to Multi-agent Systems - WordPress.com · 2017. 2. 3. · Frameworks •Frameworks have common standards –(FIPA platforms and communication languages) •Frameworks

Introduction to

Multi-agent Systems

by

Budditha Hettige

Department of Computer Science

Overview

• What is an Agent?

• Agent properties and characteristics

• What are Multi Agent Systems?

• Conventional vs Multi-agent Software

Paradigms

• Agent-Based Software Applications

• Multi-agent Development Frameworks

• Design your own Multi Agent System

2

What is an Agent?

Agent is used frequently nowadays in:

–Sociology, Biology

–Cognitive Psychology

–Social Psychology

–Computer Science

3

What is an Agent?• An agent is anything that can be viewed as

perceiving its environment through sensors and acting upon that environment through effectors

• Human Agent– Eyes, ears, and other organs for sensors, and hands,

legs, mouth, and other body parts for effectors

• A robotic agent – Substitutes cameras and infrared range finders for

the sensors and various motors for the effectors

• Software agent– has encoded bit strings as its percepts and actions

An Agent

Agent definitions

• “An agent is an entity that senses its environment and acts upon it”

(Russell, 1997)

• “Intelligent agents are software entities that carry out some set of operations on behalf of a user or another program, with some degree of independence or autonomy, and in so doing, employ some knowledge or representation of the user’s goals or desires.”

(the IBM Agent)Introduction to Agent Technology 6

Agent properties

AutonomyAgents operate without the direct intervention of humans or others, and have some kind of control over their actions and internal state.

Introduction to Agent Technology 7

Agent properties

Reactivity:

Agents perceive their environment and respond in a timely fashion to changes that occur in it.


Agent properties

Social ability:

Agents interact with other agents (and possibly humans) via some kind of agent-communication language

(Wooldridge and Jennings, 1995)


Agents characteristics

• Act on behalf of a user or another program

(Autonomous)

• Sense the environment and acts upon it (Reactivity)

• Purposeful action

( pro-activity)

10

11

Agent Environment

Agent

Environment

Sensor

Input

Action

Output

11

Multi Agent system

Many entities (agents) in a common

environment

Environment

12

Comparison of two Software

Paradigms

CONVENTIONAL SOFTWARE

Hierarchies of programs

Sequential processing

Centralized decisions

Instructions

Data-driven

Rigidity

Pre-programmed behaviour

MULTI-AGENT SOFTWARE

Large networks of small agents

Parallel processing

Distributed decisions

Negotiation

Knowledge-driven

Adaptation

Emergent behaviour

13

MULTI-AGENT

SOFTWARE

CONVENTIONAL

SOFTWARE

AGENT

Two Software Paradigms

Sequential Process Parallel Process


Agent Networks

Swarm1

Swarm 2

Swarm 3

Swarm 4

Swarm2

Swarm3

Swarm4


CONVENTIONAL Vs MULTI-AGENT

• How many “A” in the set?

A B D A C F A B D

• 10 grades

D


Conventional System

A B D A C F A B D D

1

A B D A C F A B D D

23

Sequential Process


Multi-agent System

AB

D

A

C

F

A

BD

D

3

AA

A

Who has grade “A”?

Parallel Process


Agent-Based Software

Applications

Real-Time Scheduling of Taxis

• Real-Time Management

System for over 2,000 taxis in

London

• More than 13,000 orders per

day

• In rush hours 1,500 orders per

hour

• Guaranteed pick up of clients

within 15 min’s

• A wide variety of needs and of

types of vehicles

Source: The Power of Agent-Based Software, George Rzevski20

Real-Time Scheduling of

Car Rentals

• Real-Time Management System for the European operation of one of the largest rent-a-car companies in the world

• Sequences of operations

• Delivering & washing cars

• Returning drivers

• No-shows, human errors, delays

Source: The Power of Agent-Based Software, George Rzevski

21

Real-Time Scheduling of

Seagoing Tankers• Real-Time Management System for a

London based company managing 10% of the total seagoing tanker capacity in the world

• Tankers of 300,000 tons

• 500 cargos per year

• Voyage costs £1million per 45 days

– Typical revenue £2.6million for a voyage Gulf to US

• Managing queuing before entering Panama canal

• Managing loading/unloading in ports and canals

• Frequent changes in market fees depending on demand

Source: The Power of Agent-Based Software, George Rzevski22

Multi Agent System Development

• Types of Agents– Agents

– Managers

– Activators

• Message Spaces– Local Queue

– Global Message Queue

• Ontology– Rules

– Knowledge

• Types of person

– Man

– Women

– Child

• Communication

– Speak

– Read/write

• Ontology

– Knowledge 23

Multi-agent Development Frameworks

• Frameworks have common standards – (FIPA platforms and communication languages)

• Frameworks save developer’s time

• Standardization of MAS development

• Examples– JADE

– JaCaMo

– SeSam

– Madkit

– MaSMT


Build your own Multi-Agent

System

• Get clear idea about Problem and solution

• Design a multi agent model

• Select suitable multi-agent system development framework

• Implement agents, communications

• Implement a way to get solution

• Test and tune-up the system


About Problem and solution

• Why multi-agent systems are important to your solution?


Problem&

Technology

Design an agent model

• How multi agent system solve your problem?

• Design– Agents

• Type, Task,

– Communication• Messages,

– Ontology• Knowledge, rules, actions

– Relation• Group, rule


Example


Example


Select a framework

• Language support

– Java, C#, Android

• Features

• Example

– JADE

– MaDKIT

– MaSMT


Implementation

• Develop agent by agent

• Make communication between agents


Implementation

• How agent make the solution

– First solution

– Last solution

– Average solution

– Min/max

– Some other method

• Test and tune-up your solution


Documents

Introduction to Multi-agent Systems - WordPress.com · 2017. 2. 3. · Frameworks •Frameworks have common standards –(FIPA platforms and communication languages) •Frameworks