Blue Bear Systems ResearchBlue Bear Systems ResearchHardware Architectures for Distributed Hardware Architectures for Distributed

AgentsAgents

Dr Simon WillcoxDr Simon Willcox

2424thth Soar Workshop Soar Workshop99thth – 11 – 11thth June 2004 June 2004

Building 32, Twinwoods Business Park, Clapham, Bedfordshire MK41 6AEBuilding 32, Twinwoods Business Park, Clapham, Bedfordshire MK41 6AETel: 01234 212001 Email: simon@bluebearsystems.comTel: 01234 212001 Email: simon@bluebearsystems.com

www.bluebearsystems.comwww.bluebearsystems.com

Blue Bear Systems ResearchBlue Bear Systems Research

Presentation OverviewPresentation Overview

ObjectivesObjectives Clustering Approaches for Multi-Agent Clustering Approaches for Multi-Agent

SystemsSystems Agent HardwareAgent Hardware Agent Communication FrameworkAgent Communication Framework Prototype Soar ImplementationPrototype Soar Implementation Example ProblemExample Problem

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ObjectivesObjectives

InvestigateInvestigate Multi-agent processing solutionsMulti-agent processing solutions Multi-agent communicationsMulti-agent communications

Provide pragmatic solutions featuringProvide pragmatic solutions featuring Distributed agent processingDistributed agent processing Small hardware footprintSmall hardware footprint Automatic load balancingAutomatic load balancing Fault toleranceFault tolerance Inter-agent communication between diverse agentsInter-agent communication between diverse agents

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Clustering Approaches for Multi-Clustering Approaches for Multi-Agent SystemsAgent Systems

Clustering maps naturally to multi-agent Clustering maps naturally to multi-agent processingprocessing

Two approaches consideredTwo approaches considered BeowulfBeowulf

Designer controls parallelismDesigner controls parallelism Libraries such as PVM and MPI provide communications and Libraries such as PVM and MPI provide communications and

parallelismparallelism OpenMosixOpenMosix

Single-system image approachSingle-system image approach Provides load balancing, process migration, fault tolerance, Provides load balancing, process migration, fault tolerance,

reconfigurationreconfiguration Parallelism transparent to designer (almost)Parallelism transparent to designer (almost)

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Agent HardwareAgent Hardware

Autonomous mobile applications limit Autonomous mobile applications limit space, power, etc.space, power, etc.

Two technologies under investigationTwo technologies under investigation Field Programmable Gate Arrays (FPGA)Field Programmable Gate Arrays (FPGA)

Provide flexibility of software within parallel, high Provide flexibility of software within parallel, high speed hardwarespeed hardware

Use as agents studied by University of KentUse as agents studied by University of Kent Miniature clustersMiniature clusters

Miniature Beowulf/OpenMosix SystemMiniature Beowulf/OpenMosix System

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Miniature ClustersMiniature Clusters

Power of embedded Power of embedded processors increasingprocessors increasing

Feasible to build a Feasible to build a miniaturised cluster miniaturised cluster based on COTS based on COTS componentscomponents

Systems such as Systems such as XBoard and Gumstix XBoard and Gumstix provide A complete provide A complete systemsystem

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Agent Communication Framework Agent Communication Framework #1 #1

Agent communication between disparate Agent communication between disparate agent difficultagent difficult

Agent Communication Languages (ACL) Agent Communication Languages (ACL) developed to address thisdeveloped to address this Wrap internal representation of information in a Wrap internal representation of information in a

agent neutral formagent neutral form Little support currently within SoarLittle support currently within Soar Developed communication framework and ACL Developed communication framework and ACL

wrapper for Soarwrapper for Soar

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Agent Communication Framework Agent Communication Framework #2#2

MarshallerMarshaller

OtherAgent

Agent Wrapper

JavaAgent

Agent Wrapper

SoarAgent

Agent Wrapper

RemoteObject

(CORBA)

Agent Wrapper

Other Marshallers

EmbeddedScript

Agent Wrapper

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Prototype Soar Prototype Soar ImplementationImplementation

Multi-agent SoarMulti-agent Soar Send and receive complete substructures of Send and receive complete substructures of

working memory to other agentsworking memory to other agents Locate agents in the external environment Locate agents in the external environment

that are available for communicationsthat are available for communications Consistent philosophy in the use of the Soar Consistent philosophy in the use of the Soar

i/o link structuresi/o link structures

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Soar Agent Communication #1Soar Agent Communication #1

ReceivingReceiving

I6

I8

^input-link

I9

^agents

T1

B1^bill

^tom

I6

I8

^input-link

I9

^agents

T1

B1^bill

^tom

S2

^sensor

^position

^finished

6

true

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Soar Agent Communication #2Soar Agent Communication #2

TransmittingTransmitting Similar to receivingSimilar to receiving New ^agents attribute under output linkNew ^agents attribute under output link Agent adds the names of the agents it Agent adds the names of the agents it

wishes to communicate to below thiswishes to communicate to below this

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Example ProblemExample Problem

Road search applicationRoad search application Generate a plan for Generate a plan for

searching a network of searching a network of roads with a finite roads with a finite number of search assets number of search assets (UAVs)(UAVs)

Input:Input: position and direction of position and direction of

target ground vehicletarget ground vehicle Output:Output:

guidance commands to guidance commands to search assetssearch assets

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Algorithm Architecture #1Algorithm Architecture #1

Original algorithm was a single soar agentOriginal algorithm was a single soar agent Large and complexLarge and complex UnverifiableUnverifiable

Current algorithmCurrent algorithm Uses work in agent hardware architectures to Uses work in agent hardware architectures to

produce distributed solutionproduce distributed solution Agents written in verifiable soar as defined by Agents written in verifiable soar as defined by

MalvernMalvern Partitions problem into a number of simple Partitions problem into a number of simple

communicating agentscommunicating agents Each agent individually verifiable?Each agent individually verifiable?

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Algorithm Architecture #2Algorithm Architecture #2

Soar Search Agent

Search Agent

Manager

Search Planner

Asset

Manager

Soar Search Agent

Soar Search Agent

Road

Database

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Soar Search AgentSoar Search Agent

Single agent is relatively Single agent is relatively simple written in verifiable simple written in verifiable soarsoar

Agent knows how to perform Agent knows how to perform a single taska single task From an initial position and From an initial position and

direction, define search path direction, define search path until next junctionuntil next junction

At a junction, start more At a junction, start more search agents with the search agents with the junction as their initial junction as their initial positionposition

Builds up road network Builds up road network ‘recursively’‘recursively’

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Other Agents/Processes #1Other Agents/Processes #1

Search agent managerSearch agent manager Maintains search agent processesMaintains search agent processes Monitors load balancing and fault conditionsMonitors load balancing and fault conditions

Search plannerSearch planner Receives search segments from search Receives search segments from search

agentsagents Gradually builds up a complete mapGradually builds up a complete map

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Other Agents/Processes #2Other Agents/Processes #2

Asset managerAsset manager Receives connected road segments from search Receives connected road segments from search

plannerplanner Allocates roads to the search assetsAllocates roads to the search assets

Asset controllerAsset controller On-board the UAVOn-board the UAV Maintains list of roads to search as series of Maintains list of roads to search as series of

waypointswaypoints Two modes:Two modes:

Loiter if no new roads to searchLoiter if no new roads to search Search roads via waypoint following Search roads via waypoint following

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Demonstration OverviewDemonstration Overview

Heterogeneous network of Heterogeneous network of PCs for search agents and PCs for search agents and other processesother processes

Search assets are two 6DOF Search assets are two 6DOF UAV simulationsUAV simulations Real timeReal time 3D visualisation of UAV and 3D visualisation of UAV and

terrainterrain