Chuong I. Mo dau

8/3/2019 Chuong I. Mo dau

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AGENT V CNG NGH AGENT

Chng I:

Gio vin: H Kim Giu

HC VIN BU CHNH VIN THNGKhoa Cng ngh thng tin

Nha Trang, thng 10/2011


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MC CH MN HC

Cung cp: Khi nim, c im, phn loi, kin trc v Agent

Cc h Agent, a Agent v Giao thc giao tip

Cng c xy dng cc h Agent

=> nh hng: Pht trin phn mm da Agent

Tip cn phn tch v pht trin phn mm hng Agent.


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YU CU

Hc v CNPM

Lp trnh hng i tng

Trtu nhn to

Ngn ng lp trnh C++, Visual Basic n mn hc


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NI DUNG

I. c trng ca cc h phn mm phc tp.

II.Khi nim agent v cc c trng ca agent.

III. So snh agent v i tng .

IV. Kin trc ca agent.


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I. c trng ca cc h phn mm phc tp.

Khi lngcng vic cn xl ngy cng ln.

Yu cu vtnh chnh xc ngy cng cao.

Yu cu vtnh mv phn tn.

Yu cu tnh c lp cao gia cc thnh phn trong hthng.


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II.Khi nim agent v cc c trng ca agent

Theo t in Heritage ca M:

"... Agent l mt i tng m c nh hng hay c kh nng v cquyn tc ng hay i din cho mt i tng khc."

Russel v Norvig:

"Mt agent c th c xt ti bi kh nng nhn thc v mi trng nang tn ti qua b cm bin (sensor) v kh nng tc ng ln mitrng qua cquan phn ng (effector )."

Theo Pattie Maes

Agent t ch l cc h tnh ton tn ti trong mi trng ng v phctp, tri gic v hnh ng t ch trong mi trng ny, qua hnhdung c nhim v hoc mc ch ca mnh."

AGENT ?


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=> Agent l mt h tnh ton hon chnh hay chng trnhc t trong mt mi trng nht nh, c kh nng hotng mt cch t ch v mm do trong mi trng nhm t c mc ch thit k.

AGENT ?



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Mt Agent l mt n v phn cng hay ph thng hn l hthng my tnh da trn phn mm c cc thuc tnh sau:

Autonomy (Tnh t ch )

Reactivity (Tnh phn ng)

Pro-activeness (Tnh ch ng)

Social Ability (Tnh cng ng)


Cc c trng ca agent


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Agent c th hnh ng trong nhng khong thi giantng i di.

Khng cn s can thip ca con ngi.

C kh nng kim sot nht nh i vi hnh ng v trngthi bn trong ca mnh

Agent c nh ngha da trn tnh t ch l mt thc thc kh nng kim sot hnh ng mtcch c lp vi cc

thc th khc, tr khi cn phi trao i thng tin v agentkhng c tri thc hon thnh cng vic.

Tnh t ch - Autonomy



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Kh nng tri gic c mi trng (th gii thc, ngi sdng, cc agent khc, Internet...) phn ng kp thi trongmt thi gian nht nh no .

Agent c kh nng phn ng li cc tc ng tmi trngtheo mt c chno .

Agent c kh nngsuy din t s kin v trngthi trong ra quyt nh.

Tnh phn ng (reactivity)



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Agent khng ch phn ng li mi trng, chng c thhnh ng c mc ch v ch ng tranh th thi c tc mc ch .

Agent c kh nng suy din v lp k hoch t thng tin v

tri thc m n thu nhn c.T mc tiu, agent xc nh cc hnh ng cn thit v n

thc hin mt cch linh hot, c tnh ton v ch ch chon lc t c mc tiu ra.

Vd:Agent cn hon thnh mc tiu x, n lp k hoch bao gmcc trng thi trung gian y,z... phi i qua v xc nh cchnh ng chuyn t trng thi ny sang trng thikhc.

Tnh ch ng (pro-activeness)



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Agent c th tng tc vi nhng agent khc hay con ngi hon thnh cng vic ring ca mnh hay tr gip ccagent khc trong nhng hot ng no .

Mt vi mc tiu c th thu c vi s phi hp ca ccagent khc. => MultiAgent (a Agent)

Tnh cng ng (Social Ability )



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Tnh linh hot: trong vic phn ng li cc tc ng t mitrng bn ngoi. Agent khng thc hin cc hnh ngmt cch my mc m c s la chn thch hp.

Tnh thch nghi: l kh nng t thay i thch ng vimi trng v theo mun ca ngi s dng.

Tnh lin tc theo thi gian : Agent v mt h thng l mttin trnh hot ng lin tc.

Cc c im khc



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Kh nng agent xuyn qua cc mng truyn thng in t.

Cho php gi cc chui thng ip thng qua mng.

Vd:

Nu agent di ng hot ng t ch, ngi s dng khng cnyu cu duy tr kt ni mng lin tc. Thay vo , c thcung cp cho agent nhim v, gi n thng qua mng v rib kt ni mng.

Khi agent thu c kt qu yu cu, t ng thng bongc tr li bng vic thit lp kt ni mng cho ngi sdng hoc ch s la chn mng tip theo ca ngi sdng.

Tnh di ng



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Object

L cc thc th c th tnh ton c.

c gi gn trong mt vi trng thi

C th thc hin cc hnh ng hay cc phng thc thay i trng thi.

Lin lc thng qua vic gi cc thng ip

III. So snh agent v object?


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Agent c tnh t ch: Agent c kh nng t ch hn object.

T quyt nh c thc hin hay khng mt hnh ng hay mt yucu t mt agent khc.

Agent l thng minh:

Kh nng linh ng trong hnh vi (phn x + t ch v cngng).

M hnh i tng chun khng c nhng kiu hnh vi nh vy;



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Tuyn iu khin Chng trnh hng i tng c mt tuyn iu khin ring l.

Mi Object c mt tuyn iu khin ring ca mnh.

Agent:

Mt h thng a agent l a tuyn.

Mi agent c gi s l c t nht mt tuyn iu khin t ch.

Object iu khin thng qua cc trng thi bn trong nhngkhng qua hnh vi ca n.

Cc object khc c th gi cc phng thc chung ca n.



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IV. Kin trc ca agent

Pattie Maes

Mt phng php hc c bit xy dng agents.

N ch r lm th no agent c th c tch ra thnh cu trc ca1 tp cc modules thnh phn v lm th no nhng modules c

th tng tc vi nhau. Ton b tp modules v s tng tc gia chng cho ta cu tr li

lm th no m nhng d liu cm bin v trng thi hin ti caagent xc nh actions v nhng trng thi trong tip theo caagent.

Mt kin trc bao gm cc k thut v thut ton h tr chophng php ny.

nh ngha 1


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Kaelbling

Mt tp hp c bit cc software (or hardware) modules, cthit k c trng bi nhng hp vi nhng mi tn ch ra dliu v dng iu khin gia cc modules.

Mt cch nhn tru tng hn vi kin trc agent l mt phngphp chung thit k c nhng modules ring bit cho nhngnhim v c th.

nh ngha 2


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M t cc trng thi trong ca agent.

Cu trc d liu ca n.

Thao tc c th thc hin trn cc cu trc.

Lung iu khin gia cc cu trc d liu.Kin trc agent khc nhau trn nhiu kha cnh khc nhau

v cu trc d liu v thut ton c biu din bn trongagent.

Kin trc Agent?


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Deliberative (Kin trc suy din) Logic-Based Architectures

Belief-desire-intension BDI (Suy lun thng minh)

Reactive (Kin trc phn x)

Hybrid (Kin trc lai)

Layered architectures (Kin trc lp)

Phn loi kin trc Agent?


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Da trn symbolic AI

Kin trc m qu trnh ra quyt nh c thc hin nhsuy din logic.

Cc phng php ra quyt nh Logical Reasoning

Pattern matching

Symbolic manipulation

1. Kin trc suy din


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a. Symbolic description of World

Mc ch cn t ti

Tp miu t hnh ng

Tm mt chui actions t ti mc ch.

S dng thut ton n gin

To k hoch

1. Kin trc suy din


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b. Belief-desire-intension (BDI - Suy lun thng minh)

Kin trc da trn qu trnh suy lun thng minh, trong qu trnh ra quyt nh c tin hnh tng bc, cc hnhng c thc hin xut pht t yu cu ca hm mctiu ra.

Beliefs: Biu din tp cc thng tin m agent bit v mitrng hin ti ca n (v c th mt vi trng thi trong),

Desires: Xc nh ng c ca n.

Intentions: Biu din nhng quyt nh phi hnh ngnh th no hon ton t ti desires ca n (committeddesires)

1. Kin trc suy din


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b. Belief-desire-intension (BDI - Suy lun thng minh) Beliefs = hiu bit ca agent

Desires = nhng mc ch ca agent

Intentions = nhng mc ch cn hon thnh (tp conca desires)

1. Kin trc suy din


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Cc thnh phn ca agent BDI Tp cc nim tin hin ti (belief): biu din tp cc thng

tin m agent bit c v mi trng hin ti ca n.

Hm thu nhn tri thc t mi trng (belief revisionfunction) thu nhn thng tin mi, cng vi nim tin cto ra nhng hiu bit mi v mi trng

Hm sinh cc la chn (option generation function): a

ra cc la chn c th c i vi agent (desire) da trnhiu bit ang c v mi trng v mong mun ca n.

1. Kin trc suy din


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Cc tu chn hin ti (set of current options) biu din tpcc hnh ng m agent c th thc hin.

Hm lc (filter function): biu din cho qu trnh cn nhcca agent chn ra mong mun da trn nhng iu kinang c, ang bit.

Tp cc mong mun (intention): biu din mong mun hinti ca agent.

Hm chn hnh ng thc hin (action selectionfunction): xc nh hnh ng s c thc hin.

1. Kin trc suy din


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Nhng hn ch ca kin trc suy dinVn Transduction

Tn nhiu thi gian chuyn i tt c nhng thng tin cnthit thnh symbolic representation, c bit nu mi trngthay i rt nhanh.

Vn representation

Lm th no world-model c biu din mt cch tng

trng v lm th no agent c th suy din kp thi vi sthay i thng tin.

1. Kin trc suy din


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L kin trc m qu trnh ra quyt nh c ci t mtcch trc tip, tc l s c mt nh x trc tip t tnhhung ti hnh ng.

Khng suy lun phc tp.

S suy din phc tp c th dn n khng li gii hay png v mt thi gian.

2. Kin trc phn x


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Nhng kin trc thng minh c th c to ra khng cnsymbolic (AI) representation.

Behavior thng minh c th c to ra khng cn explicitabstract symbolic reasoning (AI) mechanisms.

Tnh thng minh l thuc tnh ni bt trong h thng phctp.

Behavior thng minh l kt qu ca vic tng tc vi mi

trng.

2. Kin trc phn x


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2. Kin trc phn x


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Cc thnh phn ca Perception (tri gic):Ng ngha hc ca u vo agent.

Tp kin thc c s.

A specification of state transitions Actions c to ra bi ng ngha ca u ra agent (reaction).

Tt c vn dng symbolic c thc hin trong thi gian dch.

2. Kin trc phn x


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VdB tn nhit n gin l agent phn x:

S = {tooCold, okay}

A = {heatingOn, heatingOff }

action(okay) = heatingOff

action(tooCold) = heatingOn

2. Kin trc phn x


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u imn gin.

Kinh t.

Kim sot c kh nng tnh ton.Kh nng chu li cao.

2. Kin trc phn x


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Cc vn ca agent phn xMt lng ln thng tin c nh cn cho agent.

Vic hc?

C c th l th cng (handcraffed).

S pht trin mt rt nhiu thi gian.

Khng th xy dng mt h thng ln?

Ch c s dng cho nhng mc ch ban u?

2. Kin trc phn x


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Nhc imNu agent khng s dng m hnh ging nh m hnh ca

mi trng trong n hot ng th chng phi c y nhng thng tin cn thit bn trong c th thc hin ccaction thch hp.

Hu ht cc agent u ra quyt nh da trn cc thng tinmang tnh cc b ca ring mnh.

Cc agent u khng c kh nng hc t nhng kinhnghim gp phi cng nh nng cao kh nng ca hthng k c hot ng trong mt thi gian di.

2. Kin trc phn x


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Kt hp tnh phn x v tnh suy din Deliberative component: Subsystems to ra nhng k hoch v

quyt nh s dng symbolic reasoning.

Reactive component: Subsystems phn ng li s kin nhanh

chng m khng cn nhng reasoning phc tp.Thnh phn phn x c quyn u tin hn thnh phn

khngphn x.

3. Kin trc lai - Hybrid


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3. Kin trc lai - Hybrid


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Phn lp theo chiu ngangPhn lp theo chiu dc

1 chiu

2 chiu

4. Kin trc lp


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1. Phn lp theo chiu ngang (horizontal layering) Trong kin trc ny tt c cc thnh phn trn cc lp u

tip xc trc tip ti u vo v u ra

Mi thnh phn trn mt lp c th coi l mt agent.

4. Kin trc lp


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1. Phn lp theo chiu ngang (horizontal layering)u, nhc im

n gin. Nu ta cn mt agent c n cch c x khc nhau th s cit m hnh ny.

Tuy nhin lun c s tranh ginh trong vic ra quyt nh, mbo s tng thnh ta thng a vo mt hm iu khin trung tm(mediator) quyt nh xem lp no ang iu khin hot ng caagent.

Gi s trong m hnh ca ta c n lp v mi lp c th thc hin maction khc nhau vy c ngha l c th c n mn kh nng tngtc ln nhau.

Theo quan im thit k th y l mt vn kh v khi hot ngc th gy ra hin tng tht c chai (bottleneck) trong qu trnh ra

quyt nh.

4. Kin trc lp


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2. Phn lp theo chiu dc (vertical layering) Kin trc ch c hai thnh phn tip xc vi u vo v

u ra, ta c th coi nh l mt agent.

n gin hn rt nhiu so vi phn lp theo chiu ngang.

Phn lm 2 loi:

Mt chiu:Lung iu khin ln lt i qua tng lp cho ti khi ti lp cui

cng s to ra hnh ng cn thc hin. Hai chiu:

Thng tin c i theo mt chiu (ln) v iu khin c i theochiu khc (xung).

4. Kin trc lp


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2. Phn lp theo chiu dc (vertical layering)

4. Kin trc lp


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2. Phn lp theo chiu dc (vertical layering)u nhc im

S phc tp trong tng tc gia cc lp c gim.

Lung iu khin phi i qua ton b cc lp v th numt lp no hot ng khng n nh s nh hng nton b h thng.

4. Kin trc lp


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Chn mt kin trc Agent

Tho lun

Agent ca ti lu tr thngtin v mi trng. Da trn

nhng hiu bit n to rareasoning v planning.

Agent ca ti quan stmi trng. N nhn ra

nhng thay i ca mitrng, ci m s bt ucc hnh vi ca n.

Agent suy dinAgent phn x


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Hng dn nghin cu

1. Agent l g? Cc c trng v Agent.2. Agent v Object khc nhau nh th no?

3. Trnh by kin trc suy din.

4. Trnh by kin trc phn x.5. Trnh by kin trc lp.

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Chuong I. Mo dau