mas

Simon Lynch s.c.lynch@tees.ac.uk

intro

the basicsagent types• small scale (eg: NetLogo)• generic (eg: Jade, Boris…)• BDI (2APL, Jason, Goal…)• (BOID, BOID+N, ??)

small scale agents

theoretical basisuses & limitationscommunicationdeliberation

small scale agents – examples 1

moths• environmental• reactive• non-communicative

vants• environmental• non-communicative• complex / emergence• some agent-agent interaction

small scale agents – examples 2

fox & hounds• reactive• interactive• non-communicative

small scale agents – examples 3

ant packs• simple comms (phone a

friend)• some deliberation• social / independent?• lone –> group –> swarm

small scale agents – examples 4

path building• simple comms (broadcast)• more deliberation• social / collaborative?

mine clearance• simple comms (phone a

cleaner)• deliberative• collaborative

generic agents

eg...• Jade• Boris

...see Boris intro

uses...middleware, systems architectures,

resource allocation, brokering,mixed-metaphor agency, etc, etc

BDI agents

BDI = Beliefs, Desires, Intentions- what??

erm... informational, motivational& deliberative states -what??

ok... assumed info about the world (B)main objectives (D)plan of things to achieve (I)

BDI agents

beliefs vs facts

desires–> goals–> plans

plans–> intentions–> goals

agent

beliefsrules

run time

goal stack

2APL: bomb disposal with Harry & Sally

harry

example initial belief base of harry...

Beliefs:

bomb(3,4).

clean(blockWorld) :- not bomb(X,Y), not carry(bomb).

example goal base...

Goals :

clean( blockWorld )

harry...

example belief updates...

BeliefUpdates:

{bomb(X,Y)} RemoveBomb(X,Y) {not bomb(X,Y)}

{true} AddBomb(X,Y) {bomb(X,Y)}

{carry(bomb)} Drop() {not carry(bomb)}

{not carry(bomb)} PickUp() {carry(bomb)}

harry...

example of planning goal rules

PG-rules :

clean(blockWorld) <- bomb(X,Y) |

{ goto(X,Y);

@blockworld( pickup(), L1 );

PickUp();

RemoveBomb(X,Y);

goto(0,0);

@blockworld( drop(), L2 );

Drop()

}

harry...

example of procedural rules of harry...

PC-RULES :

message(sally, inform, bombAt(X,Y)) <- true |

{ if (not bomb(A,B) ) then

{ AddBomb(X,Y);

adoptz( clean(blockWorld) )

}

else

{ AddBomb(X,Y)

}

}

BDI implementation

beliefs (query, add, del)

goals (peek, push, pop, del)

rules (plan library)

message handling

deliberation cycles

agent

beliefsrules

run time

goal stack

designing BDI rules

the rubbish eater example (or forager or… or… or…)

Rules… world-already-cleanstanding-next-to-rubbishrubbish-somewhere

slots… name, descriptor, type (action or plan)what it achieveswhen it can be used

modifications (add & del) to beliefs & goals

designing BDI rules #1

the rubbish picker example (or forager or… or… or…)

Rule world-already-clean:

desc (world is clean)

achieves (clean world)

when (not (rubbish ?x ?y))

type action

del-goal (clean world)

designing BDI rules #2

Rule standing-next-to-rubbish:

desc (eat rubbish at ?x ?y)

achieves (clean world)

when (rubbish ?x ?y)

(eater-at ?x ?y)

type action

del (rubbish ?x ?y)

designing BDI rules #3

Rule rubbish-somewhere:

desc (walk to rubbish at ?x ?y)

achieves (clean world)

when (rubbish ?x ?y)

(not (eater-at ?x ?y))

type plan

post-goal (goto ?x ?y)

designing BDI rules #4

other considerations (some of these are inter-dependent)…

• how to handle rules to respond to incoming messages?

• how to interact with an environment (eg: assume environment is NetLogo)

• how to write the deliberation cycle

• how to connect through to a messaging infrastructure layer (assume Boris)

• sketch & explanation of complete system (“beer-mat” version)

BDI variations

BOID = BDI + Obligations

Norms - normative, legal behavior

obligations vs desires –> selfishness & altruism

strengths of legislations

other issues

• meta-agents

• message types

• sessions & dialog

• social issues

• trust & reputation

• white & yellow pages

• brokering

other issues

• types of agency – advantages/disadvantages

• examples

• cleudo

• (air) traffic control

• cloud delegation