Introduction to Multi-agent Systems - WordPress.com · 2017. 2. 3. · Frameworks •Frameworks...
Transcript of Introduction to Multi-agent Systems - WordPress.com · 2017. 2. 3. · Frameworks •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.
Introduction to Agent Technology 8
Agent properties
Social ability:
Agents interact with other agents (and possibly humans) via some kind of agent-communication language
(Wooldridge and Jennings, 1995)
Introduction to Agent Technology 9
Agents characteristics
• Act on behalf of a user or another program
(Autonomous)
• Sense the environment and acts upon it (Reactivity)
• Purposeful action
( pro-activity)
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Agent Environment
Agent
Environment
Sensor
Input
Action
Output
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Multi Agent system
Many entities (agents) in a common
environment
Environment
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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
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MULTI-AGENT
SOFTWARE
CONVENTIONAL
SOFTWARE
AGENT
Two Software Paradigms
Sequential Process Parallel Process
Introduction to Agent Technology 14
Agent Networks
Swarm1
Swarm 2
Swarm 3
Swarm 4
Swarm2
Swarm3
Swarm4
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CONVENTIONAL Vs MULTI-AGENT
• How many “A” in the set?
A B D A C F A B D
• 10 grades
D
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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
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Multi-agent System
AB
D
A
C
F
A
BD
D
3
AA
A
Who has grade “A”?
Parallel Process
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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
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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
Introduction to Agent Technology 24
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
Introduction to Agent Technology 25
About Problem and solution
• Why multi-agent systems are important to your solution?
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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
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Example
Introduction to Agent Technology 28
Example
Introduction to Agent Technology 29
Select a framework
• Language support
– Java, C#, Android
• Features
• Example
– JADE
– MaDKIT
– MaSMT
Introduction to Agent Technology 30
Implementation
• Develop agent by agent
• Make communication between agents
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Implementation
• How agent make the solution
– First solution
– Last solution
– Average solution
– Min/max
– Some other method
• Test and tune-up your solution
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