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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 ?
II.Khi nim agent v cc c trng ca 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)
II.Khi nim agent v cc c trng ca agent
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
II.Khi nim agent v cc c trng ca agent
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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)
II.Khi nim agent v cc c trng ca agent
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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)
II.Khi nim agent v cc c trng ca agent
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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 )
II.Khi nim agent v cc c trng ca agent
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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
II.Khi nim agent v cc c trng ca agent
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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
II.Khi nim agent v cc c trng ca agent
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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;
III. So snh agent v object?
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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.
III. So snh agent v object?
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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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
2. Kin trc phn x
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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
3. Kin trc lai - Hybrid
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IV. Kin trc ca agent
Phn lp theo chiu ngangPhn lp theo chiu dc
1 chiu
2 chiu
4. Kin trc lp
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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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IV. Kin trc ca agent
2. Phn lp theo chiu dc (vertical layering)
4. Kin trc lp
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IV. Kin trc ca agent
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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IV. Kin trc ca agent
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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