Xây dựng hệ chuyên gia cố vấn học tập theo hệ thống tín chỉ

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TRirCKVG DAI HOC AN GIANG
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KHOA KY THUAT - CONG NGHE - MOI TRLTCiNG

LE HOANG ANH

KHOA LUAN TOT NGHIEP DAI HOC NGANH ClT NHAN TIN HOC

XAY DU^G HE CHUYEN GIA CO VAN
HOC TAP THEO HE THONG TIN CHI
TRUCSNG DAI HOC
AN GIANG

THUVIEN

Giang vien huang dan: ThS. Doan Thanh Nghj

An Giang, 05/2009


LO^ CAM TA
Kinh dang len cha me, ngu6i da sinh thanh va chap btroc cho con vao doi!

Thanh kinh bi6t on!
TMy Doan Thanh Nghi pho chu nhiem khoa Ky Thuat - Cong Nghe - Moi Tniong
truong Dai hoc An Giang da hirdng din, giup do va dong vi&n em rat nhiSu trong suot thai

gian thirc hien d6 tai khoa luan nay.
Cac thay co bo mon Tin Hoc da nhiet tinh huong din va tao moi dieu kien thuan loi cho
em hoan thanh de tai nay.

Co chu nhiem Le Thi Minh Nguyet cung cac thly co trong Khoa Ky Thuat - Cong
Nghe - Moi Trudng truong Dai hoc An Giang da truy^n dat nhiing kien thiic Ian kinh
nghiem quy bau cho em trong su6t nhftng nam dai hoc. Do la hanh trang de em co the vitag
tin buoc vao dbi.
Chan thanh cam on!
Toan the ban be, nguoi than da nhiet tinh giup do, chia se va dong vien toi trong qua
trinh hoc tap va trong thai gian thirc hien de tai khoa luan nay.

Tap thS lop DH6TH2 da nhiet tinh giup d5 va luon d6ng hanh cung toi trong nhftng
nam qua.

Xin chfin thanh cam an'.


L^I NOIDAU
Trong nhftng nam qua, cong ngh^ thong tin da va dang co nhieu ftng dung trong nhieu
Hnh vuc trong d6i s6ng. Viec sir dung va thiSt kS cac co so dft lieu cung nhu viec lam quen
vcd cac phan mem xft ly dft lieu da dan dan trft nen quen thuoc trong ca quan, truang hoc
cung nhu doi vfti can bo, sinh vien.
Tuy nhien, tri thftc la mt dang dft lieu d|c biet horn duac xu ly bang cac cong cu cua
cong nghe thong tin chua duac dap ling rang rai. Khai niem ve tri thftc cung xuat hien nhi^^u
cung vai c^c thuat ngft "kho thong tin", "khai pha dft lieu" hay "cong nghe tri thftc" thuc sir la
thach thftc doi vfti nhftng c^n bo nganh cong nghe thong tin va ca nhftng can bo nganh khac.

He chuyen gia la chuang trinh may tinh duac thi^t ke de mo hinh hoa kha nang giai
quySt van de cua ngucri chuyen gia. He chuyen gia truac day da duac nhftc den nhieu trong

lmh vuc cua tri tue nhan tao, hay trong cac ftng dung v6 tri thftc. Tri thftc la cai con nguai cSn
dung de cai thien cuoc song cua minh (D Trung Tuan, 1999). Truac tien con nguai co nhftng

thao tac xft 1^ dft lieu, r6i ho co nhu c^u xft ly kh6i luqng Ion thong tin, r6i dSn cac dft lieu
dang tri thftc. Dich d^^u tien cua tri tue nhan t^o la phat tri^n cac may tinh "nghi" nhu con
ngubi; tiep theo la phat trien cac he thbng tea giftp con nguai teong cong viec ra quyet dinh.
Buac sau nfta cua tri tue nhan tao la hieu each suy luan cua con nguai. Viec phat trien mot

chuang teinh doi hoi hieu each con nguai luu teft va xft ly tei thftc. Gi^i quy6t duac viec nay
co nghla da tim duac each tot han cho viec sir dung va kham pha tri thftc. Mot trong nhftng
dong gop ion cua tei tue nhan tao truac yeu ciu cfta con nguai ve tri thftc la cac he chuyen

gia. Mpt hS chuyen gia la chuang trinh may tinh cho phep mo phong vi^c ra quyet dinh cua
chuyen gia. No duac thiSt ke cho ltnh vuc hep, tuang ttr nhu cai ma chuySn gia quan tam, nhu
chan doan y hqc, thiet ke may tinh, lap lich.

Kh6a luan nay ftng dung he chuyen gia trong gi^i quyt via dS, h tea sinh vien chpn
cac mon hQC phu hop, cac hoc phan co th dang ky trong hoc ky theo he thbng tin chi.


TINH CAP THIET CUA DE TAI
Trong qua trinh trubng Dai hoc An Giang dang trong giai doan chuyen sang dao tao

theo he th6ng tin chi. Day Ik giai doan chuydn giao tit phucmg phap d^o tao theo hoc phdn
sang dao tao theo tin chi nen co nhieu van de con bo ngo doi voi sinh vien va cac giang vien
trong tnrong khi chuydn sang phucrng phap dao tao moi. Cach chuyen diem tir he thong cu
theo phtrong phap dao tao theo hoc phan sang phuong phap dao tao theo tin chi, so tin chi da
hoan thanh, cac hoc phan co the dang ky, cac hoc pMn can hoan thanh, cac hpc phan tu chpn
co the chon,... Ik van d quan tam cua sinh vien va gi^ng vi^n.
Tir nhung nhu cau rat cap thiet tren cua c^c ban sinh vien va cac giang vien vk do cung

la ni tran tro cua tdt c^ cac sinh vien khi chuy^n sang phuong phap dao tao theo he thong tin
chi.

N6i tran trd cua cac sinh vi6n khi chuyen sang phucrng ph^p dao tao theo he thong tin
chi, cac ban da dat duoc bao nhieu tin chi khi chuyen sang phuong phap dao tao moi, so tin
chi can hoan thanh th^m, nhthig hoc phan can hoan thanh them la gi. Cac hoc phan nen dang

ky d6 co thS hoc t6t. D6 theo chuyen ng&nh nao do ban nen dang ky nhQng hoc phSn tu chon
nao di phu hop va hoc t6t chuyen nganh do hoac voi cac hoc phdn da hoan thanh cac ban co

the dang ky nhung hoc phdn nao dd hijc tdt nhttng hpc phan do. So tin chi cac ban duoc dang
ky trong hpc ky. Nhftng quy dinh vd didm so, kidm tra, thi va ra truong.

4

i


MUC LUC
CHI/ONG 1: TONG QUAN VE HE CHUYEN GIA1
I.JJe chuyen gia1
II.Pham vi ling dung va tac dung cua he chuyen gia1
III.Cau true cua he chuyen gia2
1.Co sd tri thi'ic2
2.Bo nh& lam viec3
3.Motosuy luan3
IV.Cac dac tinh cua he chuyen gia3

1.Tdch cdc tri time ra kiwi iliSu khien3
2.Tri thwc chuyen gia4

3.Tap trung nguon chuyen gia4
4.Lap luan tren cdc ky hieu5
5.Lap luan may rui5

6.Lap lupt khong chinh xdc5
7.Khd ndng gidi6
8.Do pluic tap vieaphdi cua van cli6
9.Chdp nhan sai lam6

V.Kit luan7

CHlTONG 2: THE HIEN TRI THUC9
I.Cac loai tri thirc9
1.Gift thieu ve tri thuc9
2.Cdc dang tri tltitc.10
II.Cac ky thuat th hien tri thirc11
1.Thi hien tri thuc bang cap ba dSi ttc^ng - thudc tinh - gia tri.12
1.1.Gift thieu12
1.2.Cac su kien nhan mt gia tri hay nhieu gia tri13
2.The hien tri thicc nh& cdc luat14

2.1.Gift thieu14
2.2.Khai thac thu tuc15
2.3.Cac dang khac nhau cua luat16
2.4.Dung bien trong luat17


III.Cac luat trong he chuyen gia18

1.Gidi illicit vide lap hum18

2.Cdc kieu lap hum da dang trong he thong lap hum19
3.Xdc dinh dp tin city cua cdu trd led nhitxdc siuit20
4.May rui trong thu thap tri thwc20
5.Tao ra tri time mod21
6.Sir twang tdc luat.21
7.Hai thai ewe cua cdc he thdng dim tren luat21
IV.Ketluan22

CHLTONG 3: CAC KY THUAT SUY LUAN23
I.Suy luan23
/.

Modus ponens vd modus tollens23

2.Gidivdndi.24
3.Gidi vdn di mot each tw nhien26
II.Suy luan tien/lui27
1.Tdngquan.27
2.Suy luan tien....28

' 2.1.

Giai thieu28

2.2.

Giai quy^t xung dot30

3.Suy luan lui32
3.1.Giai thieu32

3.2.Lett lich cac dich34
3.3.Cac dich do nguai dungdatra34
3.4.Cac dich do luat tao ra35
4.Ifu nhwoc diem cua cdc ky thuat suy luan36
4.1.Uu di^m cua suy luan ti^n36
4.2.Nhuqc diem cua suy Mn tien36
4.3.Uti diem cua suy luan lui36
4.4.Nhucrc di^m cua suy luan lui36
4.5.Ch^n giQa suy lutin tien va suy luan lui36

5.Kit harp suy luan tiin vd suy luan lui37
5.1.Cac he thong phan tach37
5.2.Ma thuat38


III. Kctluan39

CHUONG 4: ETNG DUNG TIT VAN CHON HQC PHAN THEO HE THONG TIN CHI
CHOSINHVIEN40
I.Mo ta bai toan40
1.Cdc chiec ndng chinh'.41
2.Cdc loai ngiedfi dung.41

II.Phan tich42
1.Phan tick nghiep vu42
1.1.Cac mo hinh chute nang nghiep vu42
1.2.Lucre d6 truang hop sit dung (Use Cases Diagram)43

2.Phan tich he thong45
2.1.Bilu d6 lop45

2.2.Bieu do lop tham gia cho bi6u mlu form45
III.Thi^ke46
1.Thiit hi hS thing.46
1.1.Mo ta cac lop d6i tuong46

1.2.Quan he giua cac bang (Relationships)50
1.3.Du: lieu mau cua cac luat trong co so du lieu51
1.4.Cac luat hi thiic52
1.5.Rang buoc toan ven53

2.Thiit hi nghiep vu56
2.1.D$c ta cac truong hop str dung (Use Cases Pecification)56
2.2.Hien thuc hoa cac Use Cases59
2.3.Lucre d6 tudn tu va lucre d6 cong tac59

3.Thiit ki thuat toan65
3.1.Thiet kdmo hinh ba tang cho suy luan luat (xu ly tri thuc)65
3.2.Thi^t kl tlm^t toan Forward - Chaining66
4.Thiit hi phan mini he thing67
5.Thiit higiao dien68

TONG KET DANH GIA71
TAI LIfU THAM KHAO72


DANH M^C HINH
Hinh 1.1: So sdnh chuyen gia \k h| chuyen gia1
Hinh 1.2: So sdnh ve viec giai vin d giura chuyen gia va he chuyen gia2
Hinh 1.3: Kiin trie co bin cia he thing dga tren tri thic3
Hinh 1.4: Cau tnic cua h^ thong chuan dodn h6ng hoc o to4

Hinh 1.5: So sdnh hf chuyen gia vdi chuong trinh binh thuing....7
Hhih 2.1: Vai trd cua tri thiic theo nhd tuong lai hoc A.Toffler10
Hinh 2.2: Cac dang tri thic10
Hinh 2.3: O-A-V cua cau "mdu cila chiic ghi la nau"12

Hinh 2.4: Cdc thuoc tinh cua doi tuong13
Hinh 2.5: C6c bu6c xi ly tri thiic trong h? thong dvra tren lutit15
Hinh 2.6: Mot ph3n ni dung trong b^ nhd cho bilt tu6i cua cac cd nhan17
Hhih 3.1: Ding ci suy luan ti6n vi suy luan lui trong bii to4n 8 627
Hinh 3.2: C6c hoat d^ng ciah^ th6ng suy luSn tien28
Hinh 3.3: C6c luat bi ch^y, thong tin trong bo nhcr thay doi trong suy luata ti6n29
Hhih 3.4: C4c budc suy luan lui33
Hinh 3.5: Qu4 trinh suy luan lui duoc the hien tren d6 thi34
Hinh 3.6: Cac budc xac djnh loi trong mudi modun35
Bang 4.1 Danh sach cac tic nhan nghi^p vy cua mo hinh42
Bing 4.2 Danh sach cac chuc nang nghifp vp ciia mo hinh42
Hinh 4.3: Luge d6 truing hgp si dpng t6ng quan43
Hinh 4.4: Luge d6 truing hgp sur dvmg chi tiet h| thong43
Hinh 4.5: Luge do truing hgp su dpng cho chi tiet nghiep vu44
Hinh 4.6: Luge do truing hgp si dpng cho chi tiet quan 1^ dietn44
Hinh 4.7: Bi6u d6 lip45
Hinh 4.8: Bieu d6 cac lip tham gia cho bieu mlu (form)45
Hinh 4.9: Mo ti quan h? giia cac bing50
Hinh 4.10: C6c lugt tri thic dugc ma hia trong co si di lieu51
Hinh 4.11: Cdc luSt tri thic cua hg thing52
Hinh 4.12: M6 hinh hien thuc hia ede Use Case59
Hinh 4.13: Luge di tuin tp cho qud trinh dang nhap thanh c6ng59
Hinh 4.14: Luge di cgng tac cho xi ^^ dang nhap thanh cong60

Hinh 4.15: Luge do tuan tg do d3ng nhSp that bai do khfing ton tai usemame60
Hinh 4.16: Luge do cgng tAc cho xA ly dAng nhap tht bai do khong ton t^i username61
Hinh 4.17: Lugrc do tuan tg do dang nhap thSt bai do sai mat khAu61
Hinh 4.18: Luge db cng tAc cho xii ^^ dang nhp that bai do sai password62
Hinh 4.19: Luge db tu&i t\r cho dang k^ m6i th^nh cong62
Hinh 4.20: Luge do tuSn tg cho xii ly nh|p di6m63
Hinh 4.21: Luge do cgng tdc cho xii ly nhap diem64
Hinh 4.22: M6 hinh ba tang cho xii ^^ luat he th6ng (xii ly tri thiic)65
Hinh 4.23: Cau tnic da lieu cho thu^it todn suy luan tien (Forward Chaining).66
Hinh 4.24: So do cay chiic nang67
Hinh 4.25: Giao difn dang nhfp cda chucmg trinh68
Hinh 4.26: Giao di?n chinh cua chuong trinh68
Hinh 4.27: Giao dign quAn 1^ sinh vi6n69
Hinh 4.28: Giao dign bAng diim•.69
Hinh 4.29: Giao di^n tu van70


DANH SACH CAC KY HIEU VA Tlf VIET TAT

Tie viet tat

Thuat ngCe

CSDL

Co so du1 lieu (Database)

LTM .

Bo nho1 vTnh cCru (Long Term Memory)

O-A-V

Doi tiwng - thupc tinh - gia trj (Object-Atribute-Value)

STM

Bp nho tarn thoi (Short Term Memory)


CHlTOfNG 1: T6NG QUAN VE HE CHUYEN GIA
I.Hy chuyen gia

-Hy chuyen gia 14 chuang trinh may tinh duyc thiet kl dl m6 hlnh h6a kh4 nang gi4i
van dl cila ngudi chuy^n gia hay hf chuyen gia 14 he thong dya tren tri thiic, cho ph^p mo
hinh hda c4c tri thiic c4a he chuyen gia c6 chit luyng, hay chuyen gia duyc huln luyn d6i
vdi lihh vuc cy the; cho phdp dung tri thiic n4y dl gi4i van de phiic tap thudc lmh vyc n4y.
-Hai yeu t6 cua he chuyen gia 14 tri thiic chuyen gia va lp luari; v4 he thong c6 hai
kh6i chinh 14 ca so tri thiic v4 mota suy luan.
-Ca sd tri thiic: chiia c4c tri thiic chuyen sau vl linh vyc nhu chuyen gia. Cor sd n4y
gom cac sy kien, c4c luat, c4c khai niem va c4c quan he. Nguoi ta c4n thS hien cac tri thiic

n4y 6 dyng thich hyp.
-M6ta suy lun: 14 bo xii 1^ tri thiic duyc m6 hinh h6a theo c4ch lap luan ciia chuyen
gia. Mota suy luan hoyt dyng tren thdng tin vh v4n de dang xdt, so s4nh v6i tri thiic luru trong
ca sd tri thiic r6i nit ra k^t luan hay binh luyn. Nhu v^y nguW ta din ky thuyt ve suy dien.
Thu4t ngO "mota" duyc diing vdi nghla b6 phan quan tryng trong he thing ty d^ng, ho4c
duyc trich tur thu4t ngS tieng Phap cua tir "moteurd'inference".
II.Pham vi ling dung va tac dung cua he chuyen gia
He chuyen gia yeu cau dau tu v4 vat tu toi thieu, nhung nd phuc vu nhieu cho con hgudi

trong lihh vyc cdng nghy thong tin. V6 nguyen nhan khiln ngudi ta dlu tu v4o xay dyng he
chuyen gia c6 the gom:
-Hy chuyen gia cd the hoat dng nhu mt chuyen gia trong viec truy tim thdng tin tir
nhilu nguon, tir nhieu chuySn gia.

-He chuyen gia giu lau d4i c4c tri thiic chuyen gia, ngay c4 khi chuyen gia mat di.
-H| chuyen gia cho kit qu4 ben vflng, khong bi c4m tinh v4 thlt thudng nhu con ngudi.
-Tic dy cua he chuyen gia td ra uu vi^t, nhlt 14 khi xir ly nhilu vln dl cung luc.
-C6ng cua chuyen gia cao v4 cd xu hudng tang len, trong khi gia he chuyen gia gi4m.
So sanh giua chuyen gia va he chuyen gia, ngudi ta co the neu ra:
Nhan to so sanh

Chuyen gia

He chuyen gia

Thai gian sin sang

Trong gid I4m vi^ c

Sultng4y

Dia dilm

Mot dia phuong

Tai bit k^r d4u

Dyanto4n %

Khong thay thl duyc

Linh hoat, thay thl duyc

Tlntai

SS chit

Song mai

Hiyu suit

Biln dyng

Blnviing

Tic do

Thay dli

Luon nhanh

Chi phi

Cao

Chip nhan duyc

Hinh 1.1: So sanh chuyen gia va he chuyen gia

Mot vdi ly do de h| chuyen gia dugc phat trien nhdm thay thS cdc chuyen gia la:
' - Ngudi ta cSn c6 chuyen gia ngay cd ngodi gid hay tai nhung hoi xa, nguy hiSm.
'- Vifc ty dng hda cong vigc trong day chuy^n cdn dSn chuyeft gia, ma con ngudi
khong ddp ung dugc..

-Can ttto dieu kien de chuyen gia nghi ngoi vd khi din den chuyeh gia thi c6 the thue
vdigidcao.
Mot dieu ly thu la h| chuyen gia khong nhihig trg giiip ngudi binh thudng ma cdn sii d\mg
cho c^c chuydn gia. Ngudi ta xay dyng h| chuyen gia d^ trcau:
-Ho trg chuy^n gia trong cong vi?c nh6 d^ n&ig cao nang suat.

-Ho trg chuy^n gia trong cdng vi^c phiic tap de qu^n 1^ s\r phiic tap mot cdch hieu qu^.
—- Dung l^i cac tri thiic chuyen gia khi khong cdn nhd dugc.
Tuy nhidn con ngudri co uu di^m dac bigt, khong the thay the dugc la linh cam truac ve
v^n d; dieu nay giiip con ngudi linh ho^it trong lga chon. Ngay trong each mang cong nghigp,
mdy khong thi thay the con ngudi trong to^n b^ d^y chuyin dugc.
Hg chuy^n gia cd t^c dung trong ede linh vgc nhu: Dieu khiin, thiet ke, chfin doan, giang
d^y, dien giai, giam sdt, lap ke hoach, du dodn, chin trj, lira chgn, mo phdng.
HI. Cau'true cua h^ chuyen gia
1. Cffsutrithirc

Trong he chuy^n gia, cac tri thiic chuyen gia dugc bdo qudn trong ca sd tri thiic. N6
cung Id khdi LTM trong m6 hlnh gidi quyet van de cila con ngudi
Bjnh nghia 1.1: Cor sd tri thiic (knowledge base)
Ca so tri thiic la thanh phdn chinh ben ccmh ede thanh phdn gidi vdn di trong H
thong dva tren tri thiic. Trong kSiuon khd cua h^ chuyen gia thi ca sd tri thiic dupe
dfnh nghia la mptphdn trong h$ chuyen gia chua cac tri thiic ve linh vice.

BO nh* vlnh cihi LTM
(Cdc tri thiic vi lihh vyrc)

Cor sd tri thirc

(Cdc tri thttc vi linh v\rc)

—rs
!^

LM khuyen
(Cdcs^kifn,
ede kit luan)

Ngufri dung
(Cdcstrkifn,
cdc kit luan)

JL

JL
BO nh^ tarn th^i STM
(Cdc s^ kiOn suy luOn,
cdck^tluOn)

BO nhd lira vi^c
(CdcsyrkiOnsuyiuOh,
cdc kit lufin)

Gidi vhn sk ciia chuyen gia

Gidi vin de cua h^ chuyen gia

Hinh 1.2: So sanh ve vigc gidi van de giua chuyen gia va h^ chuyen gia


2. B$nhdldmvi^c
B$ nhd ldm vi|c chiia cdc s\r kin lien quan ddn vdn (16 dang xdt. N6 tuong ling vdi
STM trong m6 hlnh gidi quyet van de cua con ngudi.
Bjnh nghia 1.2: Bq nhd l&m vice (working memory)
Mptphdn trong he chuyen gia chita ede syc kiyn cua vdn di dang dupe xit.
Djnh nghia 13: H thong dira tren tri thirc (knowledge based system)
Cdc h$ thdng dua tren tri thuc Id h$ thing phdn mini; trong dd ede tri thuc vi iinh
vifc bdi torn dupe co Idp vd luu trie trong ca sd tri thuc, vd dupe xu ly ddnh gid
nha thdnhphdn gidi vdn de dpc lap voi bdi todn.

Co-sotrithuctlnh

B^nhdr
tinh

Cor sfr tri thirc dong

Hinh 1.3: Kien true cor ban cua h^ thong dua tren tri thuc
3. Motor suyluan

H chuyen gia mo hinh hda qud trinh lap luan cua con ngu^^ri trong khoi motu suy
luan, hay cung thuong dugc goi I^ motcr suy dien.
Bjnh nghia 1.4: Motor suy luan (inference engine)

Qud trinh trong h^ chuyen gia cho phip khdp cdc su kien trong bp nh& lam yi^c
vdi cdc tri thuc vi Iinh vyce trong ca sd tri thuc, di rut ra cdc kit lu$n vi vdn di.
Mota suy luan lam viec tren cac s\r ki^ n trong bg nhdr lam viec vd tri thtic ve Iinh vuc

trong ca sir tri thirc de nit ra thong tin mdi. Vdy n6 cdn tim cdc luat khdp, ket ludn ciia luat
nay Id thong tin moi.
IV. Cdc dac tinh cua he chuyen gia

1. Tach cdc tri thirc ra khoi di^u khien
Co sd tri thirc vd mota suy lun Id cdc khoi tdch rdi. M^t khoi chda cdc tri thirc chuyen
gia v^ Hnh v\rc, khoi kia Id ca ch gidi van de dQc ldp vdi khoi ca sd tri thde. Viec phan
tdch cdc tri thuc h^ thong vdi dieu khiln Id khfa c^nh cd gid tri trong h^ chuyen gia. Bd
cung Id diem khdc bi?t cua hf chuyen gia vdi chuang trinh binh thudng.
Cdc chuang trinh mdy tinh binh thudng nhp cdc tri thuc cua chuang trinh cung vdi
thao tdc dieu khiSn tren tri thirc dd. Bi^u nay khdng ddm bdo tinh dpc lap gitta viec ma


h6a cdc tri thiic vd vigc xur \j cdc tri tfaiic d6. Do vdy md kh6 xem x6t cdc tri thiic 6 diing
ma hda vd kh6 hiSu dugc dang dung tri thirc ndo vd each ddng ra sao.
Do trong h^ chuySn gia da tdch hai khoi tri thiic vd xu ly, ede nhifm vyi bio tri va thay
doi de dirge th\rc hign. Ngudi ta de ddng thay dii mOt phin tri thiic cung nhu them bat k^
tri thiic ndo t^ri bit cii noi dSu trong co sd tri thiic.
2.Tri thiic chuyen gia

DiSm quan trgng trong hg chuyen gia Id thu th$p dirge tri thiic cua chuyen gia. Tri
thiic n4y bao gim tri thiic ve linh vgc va ky nSng gidi van de. Cdc tri thiic thu dugc ttr
nhi6u chuyen gia, hay khong nhdt thiet Id cac y tudng sdng ch6i hay doc ddo, ma Id dac
bi^t, sau s3c ve linh v\rc.

Thu^t ngft "chuySn gia" mo td nguM co ky n3ng ve gidi diing \ka &k vd gidi van d8

theo edeh hi|u qud.^g c6 the the hign khd nang l|p luan vd khd nang nay Id qud kh6 doi
vdi nhttag nguM trong cilng linh v\rc. Cdc chuyen gia la ngudi so hthi cdc tri thiic chuyen
gia linh vgc.
3.Tap trung nguon chuyen gia

H^u het cdc chuyen gia c6 k^ ndng gidi via de trong linh vpc H6n quan den ngu^h tri
thiic chuySn gia. Tuy nhiSn ngodi linh virc nay, cdc chuyen gia c6 the khong c6 khd ndng
gidi van de. Con nguM binh thir^^ng cung vdy. Chdng han khSng the diing hg chuySn gia
ngdnh y de trg giiip sdea xe dgp dugc.
Mt kh6 khdn chung doi vdi cdc nhd thiSt ke hay phdt trien hg thdng Id thu thap cdc tri
thiic chuyen gia de gidi cdc van de kh6, phiic tgp. MOt trong nhfing phuomg phdp de suit
Id tr\rc tiip ldm vigc vdi tri thiic chuySn sau ve vin de vd ldm vigc vdi bdi todn xdc dinh

t6t
Thi d\i: Gid sur ngudi ta muin phdt trien mgt hf chuySn gia dS chin dodn tit cd tryc
trae cua xe 6 to. Day khdng chi Id vin di phiic tgp md Id vin dS khong quan ly nii do
pham vi rgng cua bdi todn.

Chin dodn hg thong dign

Chin dodn hg thong xSng dau

Hinh 1.4: Ciu true cua he thing chin dodn hong hdc o to


Ngubi ta co the don gidn hoa bdi todn bang each chia bdi todn chan dodn theo cac he
thdng con, nhu he thong diu vd h| th6ng diem Tuy nhien d6 mdi chi gidi quydt dugc kh6
khan buoc ddu. Khi dong dfin m5i bdi todn con, ngubi ta vdn gpp ede kho khan khac do
phain vi Hnh v\rc rong.
4.Lap luan tren cac ky hieu

Cac he chuydn gia the hi?n tri thiic o dpng ky hieu. Ngubi ta c6 t^e dung ede ^y hieu
de the hien cac lopi tri thiic da dang, nhu cac sp kien, khai niem, hay cac ludt. Chang han

Mr b\ dm co the dupe the hien qua 6m(Mo).•
Ngodi the hiSn ede cau ngon ngtt t\r nhien 6 dang ky hieu, ede chuyen gia con xii ly
cac ky hieu nay khi gidi vfin d6. Chang han "ngu^i 6m cdn u6ng thu6c". Phdp toan vi tur
dhng ky hieu "->" dl chi phep "kdo theo" vd dung cac bi6n d6 so sdnh khdp ede cau
thuanloihon.,-'.•';

Thidu:,;
Tien de "Mo bi 6m" dugrc the hien qua 6m (Mo)..

i'

'

j'
,•

, . . X"

Luat "IF 6m THEN u6ng thu6c" du^cthl hien qua 6m(X) -> u6ng(X,,thu6cj...; -^
K6t luan thu du^c do xd ly luat vd thdng tin tien d6: uong(Mq, thu6c).

' '.;••;

Qua thi du tren, nguoi ta thdy h? chuyen gia gidi bai todn bang edeh xu ly ede k^ hieu a '.
thay vi thyc hi?n xdr 1^ s6. D6i vdi nhung nhi?m vp c6 ede thong tin is dang du lieu thi neri',
dung cac chuong trinh binh thubng. Nhin chung, co the coi cac chuong trinh nhu cac xii \ ;•

ly dii lieu vd ede he chuyen gia nhu ede xu 1^ tri thiic.,.
;. '
5.Lap luan may rui

Cac chuyen gia tinh tuong trong vi|c dung kinh n^ii^m de gidi dung yd hi?u qud bai'.;,,
toan dang xet. Qua kinh nghiem da dung, ho hi6u v6 vdn de mgt each thpc t6 yd gitt dubi '
d^ng cac may rui. Cac may rui dien hinh do he chuyen gia ddng khi jgidi van de trong m^t ,
so thi dp la:,.;
>Vdn d6 h6ng xe 6 to, kiim tra dien truoc tien..' '

;•'••..

>Trong mua he, nguoi ta hilm khi mac do bong.'

>Ndu gdp bpnh c6 tinh di truyen, ndn kiem tra lich sii benh cua benh nhan.

^

Thuc t6 cho thdy mot so ky thudt may rui da thdnh c6ng trong viec gidi vdn d6. Thep
Baraiko nam 1982 thi Minski da chu y den tim kidm may rui nhu la "ndu nguoi ta khong
the khuyen may tinh each thpc hifn t6t nhdt, thi hay lap trinh d6 may ra tim thdy mot each
ndo do".

May rui dupe ddng trong h? chuydn gia de giup ngubi ta di nhanh ddn gidi phdp.
Trong he chuydn gia, chien luge lpp luan nay khong giong nhu cac thu tpc chinh xdc cda
chuong trinh binh thubng. Chuong trinh xu ly dii li^ u theo thudt todn, nhung he chuydn
gia thubng ddng ede ky thupt lpp lupn may rdi. Thudt todn the hien m^t lopt ede nhifm vp
xdc dinh ro can thuc hien.

6.Lpp luan khong chinh xdc

He chuyen gia duoc coi Id thdnh cong trong ung dung can den lap luan khong chinh
xdc. Nhfing lopi ung dung nay dac trung bang thong tin khong chac chan, nhdp nhang hay

khong sin sang, dpc trung bdng llnh vpc do vipc suy lupn m6t edeh kh6ng chinh xdc cung

'


cap. Thpc tl thudng xdy ra nhir vpy, chlng han bdc si khdm bpnh nhdn vdo dp ciiu trong
hodn cdnh khdng hoi dupe nhieu thong tin.. -.

Thidu:
Cdc thong tin khong chinh xdc nhu "c6 the M6 mua xe d6", "mdy chay

.

ndng",... vd tri thuc khong chinh'xdc nhir "neu co ve nlng thl M khde", "xe
cuaMothudngldtlt",...;

7.Khd nang giai
H| chuyen gia dugc xay dvmg tren co sd tri thiic chuyen gia. Vdy khong nen cho ring
he chuyen gia gidi dugc b^t kj^ bdi toan ndo, dl roi that vpng ve n6. Hp chuyen gia chi
dung tot dli vdi cdc loai bM to^n mil chuyen gia giai du^e.
Neu khong c6 chuyen gia de giai vln d6 thi ngu&i ta khd hy vong c6 dugrc h^ chuyen
gia thay thS. NSu vln dh la qu^ moi Va thay doi qud nhanh thi khdng thilt ke dugc he
chuyen gia.'
8.Do phii-c tap vira phai cua van de

Ddnh gid ve loai vln dS gidi bdng h? chuyen gia, ngubi ta nhan thay cdc van d^ can
phuc tap vira phdi, khong de ma cung khong qud khd. Ndi chung neu nhiem vp de den

miirc chi cdn mot lugmg nho kiln thuc chuyen gia da giai dugc thi khd ddnh gia dugc cdng
siic cua h? chuyen gia. Tuy nhidn cung cd cdc loai nhi|m vp dcm gidn nhung can thuc hipri ' '

nhieu ldn, chdng han nhu thpc hien nhieu Ian cdng mgt vipc ra quyet djhh..

!

Van de khong dugc phuc tpp din mdc gay ra tinh trpng khong qudn 1^ ndi d tdm cua

'

he chuydn gia, chdng han nhu phdi cdn den hdng gid mdi gidi xong bdi tddn. MQt hp
chuyen gia chap nhpn cdc vln de phiic tap d muc gidi dugc trong vdng mudi ldm hai mudi
phut..;
9.Chap nhan sai lam;'
''

'

••

Ngudi ta coi he chuyen gia gidi vdn dS nhu chuyen gia, chap nhpn hp thing cd the mac ' '•(
cdc sai llm. Ve didu ndy thi chuong trinh uu vipt hom, vdi nghla chi phlp nhpn gidi ^hdp .
dung. Tuy nhien so sdnh tdng thl, ngudi ta thdy trong mgt si bdi todn eg the, vipc hp
chuydn gia cd ldi giai sai lam mang tinh ngudi hem, do cdn xd ly cdc thong tin khong,, chinh xdc, thdm chi mau thuln nhau.; ,.

Cdc chuong trinh binh thudng dp dpng cho cdc bdi todn md thong tin chinh xdc yd day ^
du. Chdng hpn do la cdc hp qudn tri co sd dtt lipu, cdc chucmg trinh kl todn.,Tuy nhienydi , .

bdi todn md da lipu thilu vd sai, chuong trinh khong thl cho ra kit qud. D6 Id tinh hudpg

ma ngudi ta ggi Id "tit cd hodc khong cd gi".V
Ngugc Ipi, bdi todn trong h^ chuyen gia it cau trdc; cdc thong tin thieu den mdc khdng
thl cho kit luan chmh xdc. Tuy vpy no vin cho cdc kit luan cd ly, thdm chi tit.

\


^^-—^^^ Doi hrgrng xfr ^^

Chirong trinh binh
thirtrng

Thong so doi s4nh~~^~-~^.

Cac he chuyen gia

Xijrly

So

Kihi?u

Sue dying •

Thu|t todn

Mayrui

T6 chiic thdng tin

Thong tin v4 dieu khien
dugc tich hgp

Tri thuc tdch rtri dilu khiin

Khd nang thay d6i

Kh6 thay doi

Di thay doi

Tinh chic chin

Thong tin chinh xdc

Thong tin khdng chic chin

Giao difn

Giao dien cau l?nli

Loai ket qua

Ket qua cuoi cung

Tinh tdi iru

Nghi|m toi uu

Hoi thoai t^r nhien c6 gi^i

thich
Khuyen cdo k&m theo gi^i
thich
Giai ph^p chap nhan dugc

Hinh 1.5: So sanh hi chuyen gia voi chuong trinh binh thvfrng

V.Ketluan

Mo hinh hi chuyen gia dugc coi nhu mo hinh gidi van dS mang tinh ngubi. Cdc die tinh
so bp nhu da ndu trong phin trin. Viic hilu cdc die tinh cua hi chuyen gia lin con ngubi cho
phbp ngubi ta thilt kl hi thong hiiu qtid..',
"i

Ngubi ta nit ra dugc cdc y kit lu^n ve ddc td cua hi chuyen gia nhu sau:•
>Cdc thdnh phin ca bdn cua cau tnic hi chuyen gia Id eg sb tri thiic, motb suy luan
vd bp nhb ldm viic•

.

>Co sb tri thbc gom tri thbc vd lihh vuc.-.• •

>Moto suy luan Id bpxbly tri thbc.
>Bi nhb ldm viic chiia cdc thong tin chuyin sSu, do chuyen gia, ngubi diing cung
cap vd do hi thong suy ludn ra.
>Hi chuydn gia cb the gidi thich edeh cb dugc kit ludn vd ly do nb d|t cau hbi vbi
ngubi dung.'.

>Mpt hi chuyen gia bao triim kho tri thiic ve vln de dang dugc chii trpng. '
>Chuong trinh binh thubng xb If dtt liiu, dirge coi Id bp xb ly tri thiic. .

>Hi chuydn gia dung lp lupn may rui dl gldi van de dbng, hiiu qud.[
>Hi chuyen gia cb thl ldm viic dubi dilu kiin thong tin khong chic chin, thong tin
chua bilt vbi cdc ky thuat lap luan kliong chinh xdc.:
>Cdc hi chuyen gia cung cb thl mlc sai llm.

.'

:.-<''

>Viic phdt triln hi chuyen gia dugc gpi Id cbng nghi tri thuc, Id qud trinh tubmg.tdc'
giba ngubi thilt kl vd ngubi dung.•

•_..''

• '•• 'i'!-i '•>

• ': J<


>Qu^ trinh thu thap, t6 chtic v^ nghien ciiu tri thiic cuachuyen gia v^ luih vuc.dugo, .,;
gpi Ih thu thgp tri thuc...

~'" .( ,

^^,,.^ ^'*

>C^c vai tr6 chinh trong h6 chuydn gia la chuy^n gia llnh vytc, k^ su tri thiic v4'^
e •nguiridung.,' • ;l

'

^

;.

\

He chuyen gia l^ hS thdng d\ra tr^n tri thiic, c6 khd nang m6 hlnh c'^ ^c tri thiic. chuySn gi^
v^ Knh vuc va dung cac tri thiic de gi^i cac van de phiic t^ip thuQC ltnh vvc nay.

;::

\,


CHlTONG 2: THE HlEN TRI THU"C
I. Cdc loai tri thirc...;
1. Gidi thieu ve tri thirc:•

Trudc khi xit ly th6ng tin tri thiic, cdc h6 chuyen gia ddng cdc ky thuSt/ffia h6a tri
thtic. Cdc ky thuat ma h6a tri thirc ndy khdc nhi^u so vdi cdch ma hda da lieu,trong ,cdc'
chuomg trinh, thuat todn xii ly dtt ligu thudmg g^lp. Cdc hg th6ng thong minh can xit ly cac
tri thiic, vd cac tri thiic can dugc biiu diln 6 dang ky hieu ma he thong xii ly dugc. D6
tinh da dang cila thuc tS, cila bdi toan can gidi vd vi ch^ng c6 k^ thu^it n^o la phh hop cho s
tit c^ cdc ling d\rng, nguiri ta cin l^ra chpn m^t ky thugt tfiich h^p d6i Vdi mgt ldp bai
toan.. .

.

j....

Cau "tri thirc la sire manh" thuimg dugc nhin manh trong he thpng thong niinh. D^ •}

tvr lfiu, hieu qu^ cua h? chuyen gia php thugc tryc tiip din chat ,hrgng tri thiic nii he thing ^
da thu th|p va se bo sung them ve b^i toan can phai gidi.

.

[

•! ;.;^ ':,-'•."•; ^

Tuy khong xac dinh dugc mgt each chinh xdc, ngudi ta cung can biet tri thiic la gi? Ndi;,.'
Id thuat ng& trim tugng nhlm chi hilu biit van $b cua m6t cd nh^n vS'chil di :da chq.^ ^
Trong he chuyen gia, tri thiic dugc xem nhu cai lien quan ch^t che den mien chu de cda
vlndecdnxdt.

Dinh nghla 2.1: Tri thirc (Knowledge)\
Tri thicc la suhiiubiitvi m(>tlTnh vice cua chit di.

-\

,
•:

Thidu
Trong ede v^n di ve y hgc, khd ndng chiia bfnh Id tri thiic. Khi xdy dpng h^
chuyen gia, chdng han nhu hg chuyen giayi y hoc, khong phai ngudi: ta muon v '

thu thap tat cd ede tri thiic chuyen gia. Chi nhung tri thiic chuyen gia dugc

chgn vd hon th6, ngudi ta chi chgn tri thiic chuyen gia theo mot vdi chu de
quan trong ciia mien chu de. Chang han ngudi ta can chgn ra ede hieu biet chi
chuyen vS benh nhilm trung mdu. Khi dy nguoi ta can cac kien thiic chuyen ve
linhvue.

Dinh nghla 2.2: LInh vuc (Domain)
La miin chu di dugc chu trgng.
Diem then chot dd phdt trien thdnh cdng he chuyen gia Id tinh tap trung cua linh vuc.
Khi mien chu de gom nhidu khia cgnh, md tri thiic can thiet chi ndm trong mgt vdi khia
canh, thi vigc xet dong thdi nhidu tri thiic cila nhieu khia canh se ldm hg th6ng mlit tap
trung vdo linh vuc chuyen sau vd dieu nay se dnh hudng ddn hifu qud cda toan bg he
thong.

Sau khi thu thdp tri thiic cua cac chuyen gia v linh vgc quan tarn, ngudi ta ma hda tri
thuc trong ca sd tri thiic. Dg thgc hign vigc ndy, ngudi ta cdn cdu tnic cac tri thiic trong he
thong mot edeh phil hgp d6 hg thong gidi quySt vdn d6 thugn tign cung nhu mot chuyen
gia. Do la yeu cau the hien tri thiic.


Bjnh nghia 2.3: The hifn tri thiic (Knowledge representation)
The hi?n tri thuc la phuang phdp cho phep ma hoa tri thAc trong ca s& tri thuc
cua h? thong..
2. Cdc dang tri thtic-

Trong qud trinh phdt tridn c^a loai ngudri.'tri thiic dupe ding de con ngudi hodn thien '
minh, dS lam viec t6t hon vdcu6i cbng I^ t^o ratri thtic mdi. Tri thiic gin vdi cdcbudc
phat triin loai ngu^^i thong qua viec xay dung nhan each con ngudi, tang nang suit lao
dong vd biet duQfc tri thtic Id quan trQng, c6 vai tr6 nhu tien t^ hay quyen l\tc.

^"

Hinh 2.1: Vai trd cua tri thuc theo nha tirtmg lai h(jc A.Toffler

.^ '

•

Tir lau, cac nha tarn ^^ hpc v6 nhgn thtic da xay dung 1^ thuyet gidi thfch vS van d6. ,,
Cdc 1^ fliuyet ndy da cho ngudi ta thay ede dang tri thuc con ngudri hay dung, each con 'l
ngudi t6 chtic cd suy nghT tren cdc tri thtic dd, va edeh ding cdc tri thtic mot edeh hi^u
qud. Cdc nha nghien ctiu cung ding cdc kit qud nghidn ctiu ndy di phdt triin cdc ky thuat
thi hi^n tri thtic tren may tinh.:.' '•

Chang cd ly do ndo gidi thich dupe each ti chtic tri thtic con ngudi vd cung chdng cd
ciu tnic thi hifn tri thtic ndo Id ^^ tudng cd. Vdn de la con ngudi phdi cHpn; kj^ thudtthi
hien tri thtic tren mt so dang tri thiic. Nam d^ng tri thtic lift ke trong bang sau:

. • .• .
"fi ^

Loai tri thiic

Thidu

•$

Tri thuc thu tiic

Cdc luat, cdc chiin luge, licit, cdc thu tuc

•'•

Tri thuc mo ta

Cdc khdi niem, cdc doi tugng, cac sir kien

Tri thuc meta

Tri thiic vi cdc dang tri thiic khdc vd each sir dyng chting

Tri thuc may rid

Cdc luat may rdi

Tri thuc cdu trie

Cdc tap luat, cdc quan he khdi niem, khdi niem vi quan he giua
cdc dii tugng.
Hinh 2.2: Cac dang tri thiic

10


Dien gidi chi tiet vd timg dang tri thiic, ngudri ta nhan xet co tinh so sdnh nhu sau:
1.Tri thiic thu tyc dien td cdch gidi quydt van dd. Loyi tri thiic thd tuc cho biet
phuong huong thyc hi^n cdc hoat d^ng. Cdc luyt, cdc chien lupc, cdc lich vd
cdc thu tyc Id cdc dang dye trung cua tri thiic thu tyc.
2.Tri thurc mo td cho bi^t mot van dd dupe thay nhu thi ndo. Tri thiic mo td

.

gom cdc khdng dinh don gidn, nhan gid tri chan ly la diing hay sai. Tri thiic mo
td cung co the gom mpt xau cdc khang dinh de khang dinh de dien td ddy dii
hon vd d6i tupng hay mpt khdi nidm ndo d6.
3.Tri thiic meta dien td tri thuc vi tri thuc. thuat ngu "meta" 6 day mang y

nghta dien td ve bdn than ddi tupng. Loyi tri thiic nay giiip lyra chpn tri thiic
thich hpp nhat trong s6 cdc tri thiic khi gidi vdn de. Cdc chuyen gia ding tri
thiic meta dd tang hipu qua gidi vdn dd bang cdch hudng lap luyn vd mien tri
thiic co khd n3ng hon cd.'

". ' '

4.Tri thurc may rui dien td luyt may riii, cung cdch may riii din dat qud trinh lap
lun. Tri thurc may riii cdn dupe gpi Id tri thuc nong can do khdng dam bdo
chinh xdc, khoa hpc. Tri thiic may rui xuat phdt tvr cdc kinh nghipm, tir tri thiic
vd vipc gidi vdn de qud khii. Cdc chuyen gia thudng dimg cdc tri thiic mang
tinh khoa hpc ve van dd nhu cdc didu lut co bdn, cdc quan h| chiic ndng..,.

R6i chuydn chiing thdnh cdc tri thiic may riii don gidn de thudn tien cho vide
gidi vdn dd.', '.

5.Tri thurc cau true dien td cdc cdu true cua tri thiic. Doi vdi mdt he chuyen gia ;, ^

thi tri thiic cdu tnic thi hien cdch td chiic tri thuc, md hlnh cdc tri thiic. Do vyy i 'r;
tri thurc cdu true lien quan den cdc loyi tri thiic, chiic n3ng vd quan hp giiia cdc
tri thiic.•'

;

• ';'

••': 'r. ~.

II. Cac ky thuat the hien tri thiicL ^';
Trdi qua nhieu chang dudng phdt tridn ciia cdng nghf thdng tin, cdc nhd nghien ciiu vd i '"
ling dung he chuydn gia da cho thay mdt sd cdch the hipn tri thiic cd hieu qud trdn mdy tinh.
Cd n3m kj^ thudt pho thdng nhat dilng dd phdt tridn mpt hp chuydn gia Id:', . .
>Cp ba doi tupng - thupc tinh - gid trj.•

.

•,

.

': \,

>Cdc luyt.V•'^ '.
>Cdcmyngngttnglua.,••

•..^-'' \-4

>Cdc khung.. ,• ,< '
>Logic'

.

<•.-

•

i

: '

,

Moi ky thuyt nhdn mynh vdo mpt myt ndo dd cua van de, chii khdng xet day dd, cdc khia^'' t

canh cua van dd. Mi ky thuyt cd uu, nhupc diem doi vdi mpt loyi tri thiic cy the^ Do vyy vipc' '
chpn mpt
thudt the hien tri thiic mpt cdch hpp ly
se cho phdp thd hidn cdu trie tri thiic cd;.
p ky
ypp
ypp
hieu qud doi vdu6i d^ng "ndu... thi..." thi h? chuydn gia sur dung ky thudt thd hipn theo l4

thiic nhu xur ly cdc luat thi phd hpp vdi cdch gidi md chuyen gia quen dp dimg.

11-


1. The hien tri thirc bSng cap ba doi tirgng - thugc tinh - gid tri
1.1. Gioithicu

L^ thuyit nh^n thuc coi trgng vifc thi hi^n vb ti chtic cdc tri thtic. Con nguoi
deu dung cdc su kien nhu nin tbng ca bdn. M6t su kin Id dgng tri thuc md td; trong

mgt so truang hgp cho phdp hieu ve mQt s\r kidn hay ve vin dd.
Trong hf chuyen gia, cdc sir ki?n duorc ddng di mo td cdc phan cua khung, mang
ngft ngMa hay cdc luat. Chung cung duac dimg de m6 td quan he gifia cdc cau true

tri thiic phuc t^p hon va dipu khien viec dung cau tnic nay khi gidi van de. Mt su
kifn thudtng dugc tham chieu nhu mot menh d€.

Dink nghia 2.4: M^nh de (Proposition)
M$nh di la mQt kh&ng (l\nh dung hogesai.
Menh &h nhan gia tri logic, tiic diing hoac sai, TRUE hay FALSE vd se dugc
dimg khi xir ly cdc tri thiic khde.:
Thi du
M^nh d6 co thl Id cdc cau don gidn nhu "meo mdu den", "qud b6ng
xanh" hay cdc cau phiic hgp nhu "triri day may vd gi6 to"...

MQt sg ki^n cung co thi dugc dung di gdn mt gid tri rieng cho dii tugng ndo
d6. Thi d^ nhu cdu "mdu cua qud bong la xanh" dung de gdn gid tri "xanh" cho mdu
sdc ctia "qua b6ng". Loai su ki^n ndy dugc coi nhu pdp ba doi tugng - thuoc tinh -

gid trj ky hi^u id O-A-V (Object - Attribute - Value).

Hinh 2.3: O-A-V cua cau "mdu cua chiec ghe la nau"

Mot O-A-V dugc dung de the hifn cdc menh di, don gidn hay phuc tap. Cdu trtip
cda O-A-V gom ba phan, dmg voi dii tugng, thuoc tinh vd gid tri thugc tinh.

., :. •,'

Thidij:
Cdu "mdu cda chiic ghi la nau" theo ciu tnic O-A-V thi d6i tugng dugc xdc

dinh la "chiic ghi", thugc tinh la "mdu" vd gid tri 1^ "nau'.

Doi tugng thi hipn trong cau tnic O-A-V co thi dugc vat ^^ hoa nhu cdi xe, qud
b6ng, hay vat trim tugng nhu tinh yeu, su sing. Thuoc tinh id tinh chit hay nhfing
net quan trgng de nhdn ra doi tugng. Gid tri cho biet thugc tinh nhan mgt th6 hign eg
thi. Gid trj c6 kiiu da ligu tuy thugc vdo tinh chit cua thugc tinh, c6 thi la logic, si
hay cha. Viec dung nhieu thugc tinh dh mo td doi tugng nhu Uong cdc khung hay
mgng ngB nghTa cho phep mo td ro ndt hon vd cdc doi tugng. Dii tugng c6 the c6
nhiiu thugc tinh.


Thidu

dudng ki'
mdu

tTQng lug
d6i tugng

thugc tinh

gia tri

Hinh 2.4: Cdc thugc tinh cua doi tirgiig

1.2. Cdc sir kign nhan mgt gid tri hay nhieu gid tri\ .,

Ve bdn chat, mgt vdi thugc tinh ciia d6i tugng dugc s\r kign mo td chl nhan mgt ,
gia tri, hoac nhannhieu gid trj. Ngudi ta ggi cdc sukign d6 Ids^ ki$n nhgngid trj,..:.
dan hay s^ ki$n nhdn nhiiu gid tri. Thugc tinh trong cdu tnic O-A-V se dugc thi^t '<

kS nhn mgt hay nhieu gid tri. Viec chgn l\ta bao nhieu gid trj cho mgt su kien tuy •
thugc vdo dg uy^n chuyen c6 the c6 dugc trong khdu the Men tri thiic.
Thfdy:
Dung O-A-V de the hign mgnh d6 mo td viec dgc dp suat tren dong h6 do.

Doi tugmp Id "dong h6 do" vd thugc tinh la "dgc dp su^t". Cdc gid tri c6 the v
l^y la xuong, 6n djnh hay len. KM can thong tin ve dp suat do dong h6 chi, hg
thSng hdi:
He thong: Hay cho Met dp suat do dong ho chi, ling vdi trubng hgp ndo trong s6
cdc trudng hgp sau:
>Kim cM xuong.

>Kim on djnh.
>KimcMl^n.
Trd 16i: CM xuong.
Ve m^t logic, dp suat dong ho cM c6 mot trong ba gid trj. Ngudti ta can thiet k^
O-A-V nay c6 gid tri dan.

Ngu^i ta cd the dilng c^u tnic O-A-V dl the Mgn mgt trong cdc khd nang. Liic
ndy cau tnic O-A-V dugc tMet ke de nhan eid trj don. Tuy nMen khi can chgn nhieu
trong so cdc khd ndng thl ngu^i ta dung cau tnic O-A-V nhan nMeu gid trj. Chang

han can chgn mgt s6 tieu chaii &h tuyen thu ky; dfli tugng la ngudi, thugc tinh la
"Mnhdgng", cdc gid trj Id "cao, beo, cdnd6i, n^ngcan...".•',_
>He thong: Chgn trong cdc gid trj Id "cao, bdo, can d6i, nng can,...". '.
>Ngudi dung: cao, n?ng can..

'•'....,

>Cd hai logi s\r kign O-A-V don vd da gid trj d^u cho phdp ngam djnh su

suy Man. KM ngudi dung chgn mgt gid trj cua danh sach, he thong se

' 13


khang dinh mpnh de ling vdi gid tri nay chpn ndy Id TRUE (diing), vd vdi
cdc gid tri khdc la FALSE (sai). Chdng hpn Me chpn mot sd chi tieu cho
thu ky, he thong nhpn dupe thong tin tit ngudi diing rang kh6ng nhung
thu ky sS cao va npng can ma con khdng beo. Hay khi xem mpt ddng ho,

ngudi si dying tea 16i chi^u chi kim Id "xudng", hS thdng khong chl Met
syr kipn ndy md con biet dp suat khong ten va khong on djnh. Khia cpnh
nay cua O-A-V dupe quan tdm hon so vdi each the hifn bdng cau don

gidn chi nhpn mpt gid tri don nhu "chi Nyi xinh".
2. Thi hien tri thiic nhd cdc Mat
2.1. Gidithipu
Cac syr kiSn do ngudi diing cung cdp rdt cd •} nghla d6i vdi ede hopt dpng cua he
chuyen gia. Chiang cho phdp hp thdng hiiu teang thai hiSn tyii cda thS gidi. Duong
nhien khi gidi bdi todn, hp thong cd cac tri thiic phu, tri thiic bd sung pd quan hd vdi
ede sp kin ndy va ldm cho tri thiic vd hp thdng se tdng them. Mot sd cdu true tri
thiic thong dying teong thi^t kS hd chuyen gia md ydu cdu sur dymg them tri thiic bd
sung la cac Mat.

Dinh nghla 2.5: Luat (Rule)
Cdu true tri thiic dung di lien kit thong tin da biit vdi cac thong tin khdc;
cac thong tin ndy cd the duQC suy luan de ngudi ta hieu biet them.\

Tri thuc dudi dang lut dupe xep vdo cac tri thuc thu tyc. Luat gdn thong tin da
cho vdi mdt vdi hopt dpng. Cac hopt dpng ndy cd thd la khdng dinh vd thdng tin mdi

hay thu tyic se dupe thpc hidn. Bdng edeh ndy, lupt md td edeh gidi quydt ydh dd.
Ve mdt logic, cau tnic cua luat ket noi mdt hay nhidu gia thiit, hay cdi cd trudc
teong cau IF, vdi m@t hay nhieu ket Man, hay dupe gpi Id kit qua teong cdii THIjN.
Thi du^ !i
IF

Mdu cua qua bdng la mdu xanh' ' ; . .

THEN Tdithich qua bdng
Ndi chung phan gid thidt cua mdt Mat cd thd gdm nhidu gid thiet nhd gan vdi
nhau thdng qua ede phdp logic AND (vd) hay OR (hope) hay cd hai. Lupt cung cd
thd diing cau ELSE (ngupc lpi thi) diing cho cau suy lupn khi gid thidt bi sai.
f
Trong hp thong dyra teen ede ludt, ngudi ta thu thpp ede tri thiic linh ypc teong
mdt tap vd luu chiing teong co sd tri thiic cua he thdng. Hp thdng dung ede lupt nay
cung vdi ede thdng tin teong bp nhd dd gidi bdi todn. KM cdu IF cua lupt khdp ydi
thdng tin teong bd nhd, he thong thuc Men ede hopt dpng md ta teong cau THEN cua '.
Mat. Lire ndy Mat dupe xem nhu da thuc Men hay chdy (fire); cau THEN dupe bo'
sung vdo bp nhd.

Thidu
Ban dau co sd tri thiic cd hai ludt, vd bp nhd ldm vipc Id rdng. KM nhdn dupe
ted ldi "dd" cho cdu hdi "xe mdu gi?", hp suy dien cua hd chuyen gia dyra teen
ludt thuc M|n ede Mat vd rut ra dupe thong tin mdi "se mua xe".

14


h

IF xe do
THEN s6 thich

IF thich
THENsemua

IFxedl
THEN sg thich

IF thich

i

IF xe d6
THEN se thich

MM IF thich

THEN sg mua ^^

THEN sgmua

xedd

xe d6
sg thich

1

k

IFxedd
THEN sg thich

IF thich
THEN sgmua

1

xe d6
sg thich
sgmua

H6i: xe mdu gi?

Trdldkdd
Hinh 2.5: Cdc birdc xir Iy tri thuc trong he thong dva tren luat

Viec xd ly cdc lut trong he thong dira tren lu^t dupe qudn \^ bdng mdt modun
goi Id b suy dim. Thi dyi trgn mo td hdnh vdi hdnh d6ng cda bp suy diln.
2.2. Khai thac thu tuc

Ngodi viec sdn sinh cac thdng tin mmpt luat co the thuc hien ede hdnh dpng. Hdnh dong trong cac luat c6 the Id tinh todn
don gidn, nhu Id:
IF Can dgndi^ntich hinh chiinhdt.
THEN Dien tich = chiSu ddi * chiSu rong
Be thuc hifn cac thao tdc ph^c t^p hem, nhieu he chuyen gia truy nhdp ede thu
tuc ben ngodi he thfing. Chuong trinh lp^i ndy da phan la phan mem ve co s6 du:
li|u, chuong trinh ng6n ngii C, ... Chiang c6 the duac viSt bang ede ngdn ngp:. lap

trinh hay ede l^nh trgn bdng tinh.• .

Thidu:,
>Lu|t liSn quan den thd tpc chuong trinh:

IF

•'',

xemb6iANDkhdch = trd.

'-! • '

THEN gpichuong trinh "b6i" AND tinhtifn ; ' .
>Luat HSn quan din thao tdc cua bdng tinh:.;
IF

:

tinhluongthdngtu. •"' '

THEN thdng = 4ANDmofileluong.XLS
>i Luat liSn quan din vifc tim kilm thong tin:

IF

,

' •,.,

..

• ',

''•''- ••

biltslbdodanhldX.. ?

THEN md file dilm.001 AND tim dilm vdi ma = X^
Nhin chung khd nang truy nhap hay thay doi thdng tin nhdr chuong'trinh;{ben
ngodi trio dieu kien dl cong viec thilt kehe chuyen gia trd nen uyln chuylhhon. C6
the ddng khoi luong Ion cac thong tin c6 trong co sd du lieu vd bdnjg tinh, hay thay
doi ede thdng tin nhd chdc nang ho trpr quylt dinh cda hd thing xd 1^ luat." ; .. •

j.

15

'