A Multi-Agent Systems Based Conceptual Ship Design Decision Support System

The Ship Stability Research Centre

Department of Naval Architecture and Marine Engineering Universities of Glasgow and Strathclyde

Bekir S. Türkmen

• Design Exploration and Support

• Distributed Architecture

• Encapsulation of Design Experience

Motivations

What is an agent?

An Agent : one that acts or has the power or authority to act or represent another.

An Intelligent Agent is the agent does the things rationally in a given situation (Russell 1995)

Intelligent Agents

• Autonomy• Collaborative Behaviour • Adaptivity • Mobility• Proactivity• Reactivity

Multi-Agent Systems

MAS- Three Important Questions

• Communication

• Control

• Co-ordination, Collaboration, Negotiation

Communication

Semantics and Syntax

• KQML, FIPA-ACL• KIF, FIPA-SL

FIPA-ACL

(INFORM

:sender ( agent-identifier :name Sender@BEKIRN:1099/JADE :addresses ()

:receiver (set ( agent-identifier :name Receiver@BEKIRN:1099/JADE) )

:content "Hello SSRC"

)

FIPA-SL

(query‑ref

  :sender (agent-idenfier :name B) 

     :receiver (set (agent-identifier :name A))

  :content

    ((iota ?x (p ?x)))

  :language FIPA-SL

  :reply‑with query1)

KQML/KIF

(evaluate

:sender A :receiver B

:language KIF :ontology motors

:reply-with q1 :content (val (torque m1)))

 (reply

:sender B :receiver A

:language KIF :ontology motors

:in-reply-to q1 :content (= (torque m1) (scalar 12 kgf)))

Control

• Centralized

• Federated

• Autonomous

Co-ordination

Auctions

Contract-Net (Task Sharing)

Planning

Game Theory

Argumentation

Catalogue of Conflicts

Proposed IA Architecture

Communication Layer

Coordination Layer

Conflict Resolution Module

Optimisation Module

Knowledge Base for Conflicts

• Rule-based

• Case-based

Optimisation Module

• Local-Search Algorithms

• Global-Search Algorithms

Learning Module

Task Layer

ENVIRONMENT

Acquaintance Module

Task Layer

• Knowledge Base

• Wrapped Simulation Tools

Acquaintance Module

• List of Agents

• Agents’ work definition

Intelligent Agent Architecture

User Interface

Proposed MAS Architecture

Static Stability Agent

Dynamic Stability Agent

Evacuation Agent

Resistance Agent

Hull Generation Agent

CFD Agent

FEA Agent

Worker Agents

Multi-Objective Optimisation Agent

Multi-Attribute Decision Maker Agent

Decision Theoretic Agents

3D Real-Time Simulation / Virtual Reality Agent

User Interface AgentsGeometry Transfer

Multi-Agent System Architecture

………………………..

Decision-Theoretic Agents

Multi-Objective Optimisation Agent

Multi-Attribute Decision Maker Agent

Decision Theoretic Agents Ranking and Selection Methods

TOPSIS (Technique for Order Preference by Similarity to Ideal Solution)

……

Multi-Objective Optimisation Algorithms

VEGA (Vector Evaluated GA)

NSGA (Non-Dominated Sorting GA)

NSGA2 (A Fast and Elitist NSGA)

SPEA/SPEA2 ( Strength Pareto Genetic Algorithm)

Multi-Objective Optimisation

• Decision-Making Before Search

• Decision-Making After Search

• Decision-Making during Search

Comparison of MOGA Methods

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Objective Functions :

f1(x) = x2 ; f2(x) = (x-2)2

Figure 1. VEGA Results

Figure 2. NSGA Results

Figure 3. NSGA II Results

Figure 1

Figure 3

Figure 2

Integrated Decision-Making and Search

In order to reduce the calculation cost and scalability we guide the search by introducing designer preferences into search.

• Applied as A Priori and Progressive,

• Final Selection from Reduced Pareto-Set

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Proposed Approach for Introducing Bias

•NSGA II + TOPSIS Algorithm

• Reference Point Method Approach

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NADIR POINT

IDEAL POINT

Proposed Approach for Introducing Bias Continued

Two modifications to introduce bias,

• Modification of Elitist Strategy

• Modification of Crowding Distance Assignment

Preference is given as, one unit of a is worth at most x units of b

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Internal Hull Subdivision Optimisation

Objectives

• Survivability –Max.

• Cargo Capacity (In Car Lanes) Max.

• Limiting KG – Max.

Constraints

Two Adjacent Bulkhead Distance greater than SOLAS’90 Longitudinal Damage Extent,

SOLAS’ 90 Regulations,Limiting KG Reduction for operational Life cycle

Internal Hull Subdivision Optimisation

Internal Hull Subdivision Optimisation Continued

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Cargo Hold Capacity

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Kg Important

Hs Important

Cargo Capacity (Car Lanes)

Internal Hull Subdivision Optimisation Results

Distributed Optimisation Test Problem in A Multi-Agent Systems

Distributed Optimisation in A MAS

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Early Results

Conclusions and Future Development

Advantages of proposed approach

• Distributed Computation (Less computation time)

• Distribution of Expertise (Intelligent Agent Architecture)

• Integrated Multi-Criteria Decision-Making and Decision Support Environment.

Future Research

Integration with CAD Environment

Case Study for Intelligent Agents in Multi-Agent Systems

Questions