T~p chI Tin hQc
va
fJieu khie'n hQC, T,
16,
S,4 (2000), 14-22
'" A ,:::::,( '"
VE M9T PHU'O'NG PHAP HO TRq QUVET
f)~NH
CH9N NGHE CHO
,,!
A
,,"A ••
H9C SINH PHO THONG TRUNG H9C DlrA TREN SUV DIEN MO'*
VU MINH LOC
Abstract.
In this paper, we examine a method of building Decision Support System for students in making-
career choices based on the combination of Fuzzy reasoning method and approximate reasoning method based
on measure function on hedge algebras,
T6rn
tJ{t.
Bai bao d'e c~p dgn mot phiro'ng ph ap h6 tro: quyet dinh chon ngh'e cho h9C sinh pho' thong trung
hoc du'a tren phtro'ng ph ap suy di~n mer theo lu~t
ho-p
thanh
Max-Min
va.
phirong phip suy di~n met dung
ham do cila dai so gia tu',
1.
GI01
THI~U

khac nh au. Chhg han do hoan canh gia dmh kho khan
thiic ep manh ho'n, me?t hoc sinh du muon tigp tuc hoc len dai hoc ciing danh gac lai nguyen vc;>ng
M
tlrn mi?t viec lam co th~
giiip
5n dinh kinh tg gia dinh. Me?t hoc sinh khac co hoan canh kinh tg
gia dlnh tot ho'n lai co nguyen vong "muon thu nhan
nhieu
kien tlnrc" thl viec hra chon "tigp tuc
hoc
(y
truong dai hoc" la chdc chlin,
Di?ng
CO"
thuc d~y khi chon hirong di nghe nghiep bao gom cac yeu to: hoan canh gia dinh, kha
nang hoc t~p, nguyen vorig , , la hi~n tu'orig tam H, dtroc th~ hien manh yeu khac nhau
(y
t
irng ngiro'i
cu th~ nhir nhirng t~p rno'. T5ng hop cac thOng tin ve cac di?ng
CO"
ma mi?t ca nhan earn nhan
duxrc
M
di den quyet dinh chon hircng di nghe nghiep phii ho'p la bai toan co th~ giai diro'c bhg suy di~n
mo , Ni?i dung t5ng quat cua pluro ng ph ap co thg mo t<l.nhu sau:
Chung ta ky hi~u
Pi,
i
=

CO"
thuc d~y ciia m9t ca nh an hoc sinh va hirong nghe nghiep
*
Cong trinh nghien ciru
duac
su he tro mot phan kinh phi cua Chuang trinh Nha rnroc ve Nghien ciru
ca
ban.
HO TRQ' QUYET f>)NH CHQN NGHE CHO HQC SINH PHO THONG TRUNG HQC
15
nen chon
se
phu ho'p nhat doi v6'i d, nhiin d6,
Vi v~y ta dtra vao cac dai hrong bien ng8n ngii' A, B, C chi d9 do d9 manh yeu cua cac d9
n
g
CO',Cac dai hrong nay e6 thg nh~n cac gia tri ng8n ngfr bigu thi rmrc d9 manh yeu ciia cac d9ng CO'
nhir: Yeu (Weak), trung bmh (Medium) va manh (Strong), Gia tri ctia cac bien
A, B, C
tu'o'ng irng
vci cac ky hieu la: Ai, Bi,
C, , ,
Vi~c xac dinh dung ditn cac d9ng CO'cua cac h9C sinh la m9t van de quan trong. De' thu diro'c
cac thong tin khach quan ve d9ng CO',cac chuyen gia dua ra m9t h~ th5ng cau hoi lien quan den
cac d9ng co' thtic diy h9C sinh hra chon hiro'ng nghe nghiep. Cac thong tin td, lai cac cau hoi do se
dircc danh gia dinh hro'ng bhg so rmrc d9 m anh yeu ciia cac d9ng CO',Cac gia tr~ nay diro'c kf hieu
la:
ao,
b
o

=
C
i
, t P
=
Pi, Khi do
bai toan chon
htro'ng nghe
nghiep cua
h9C sinh c6 the' phat bie'u dutri dang bai toan suy di~n me nhtr sau:
Rule
1: A
=
Al
and
B
=
Bl
and
C
=
C
1
' , ,
t
PI
Rule 2:
A
=
A

b
o
,
Co ,
Conclusion P'
trong do: {Rule, Rule 2, Rule 3} la t%p tri tlurc chuyen gia.
Trong bai bao nay chung toi trinh bay phiro'ng ph ap hinh thanh h~ tro' giup quydt dinh chon
htrrrng
di nghf nghiep
cho h9C sinh t5t
nghiep
ph5 thOng trung h9C bao gom
cac
n9i dung sau:
- Thu nhan thong tin bhg plnrong phap td.c nghiern dung h~ thong cau hoi.
- D1!a
tren
thOng tin thu
nhan
dircc, x~ ly bhg l%plu~n
mo
theo
2
phircrig
ph
ap: phiro'ng
ph
ap
suy di~n mo theo lu%t ho'p thanh Max-Min va phircng phap suy di~n mo' dira tren ham do cua dai
so gia tu-, Sau d6 ket ho'p ket qua ciia hai phtro'ng ph ap de' dua ra lai khuyen cho h9C sinh,

ly,
H9C sinh du'<?,cgiai thlch
ky
VElmuc dlch
y
nghia cila cong vi~c tham gia va each thu:c tra U)'i
d.u hoi, C6 20 cau hoi ho~c nhirng g9'i
y
nHm hutmg dh hoc sinh hie'u vEltim quan tr9ng cua vi~c
chon nghe nghiep va xac l~p su' earn nh~n cua hoc sinh ve nhirng van de co lien quan Mn vi~c chon
nghe nghiep nlnr: hoan canh gia dlnh, nang hrc ban than hie'u biet ve nghe nghiep, Ba cau hoi tiep
theo nhjirn thu nh~n
U'CYC
muon cua hoc sinh theo timg
hircng:
tiep tuc hoc ngay dai hoc ho~c vao
hoc trtro'ng day nghe, triro'ng chuyen nghiep ho~c tlrn vi~c lam ngay.
So'
do
cua phirrrng phap W!n hanh
DJ litfu
tif
f';p
Cd sd
tr;
th';c
Nhap
ti/
han
ph/m

ltit·
MV!ler;
I
3. SUY DIEN
MO'
DVA TREN Li THUYET T~P
MO' VOl
LU~T HQ'P THANH
MAX-MIN
3.1. M6 hinh bai toan l~p luan roO-
va
phiro'ng phap ghH
De' gi<l.im9t bai toan l~p luan mer ngiro'i ta thirong du'a tren tri thirc va kinh nghiern cua chuyen
gia, diro'c cau true bhg h~ lu~t 6' dang t5'ng quat nhir sau:
Rule 1: if
Xl
= All
andX,
= AI2 and Xm = AIm then Y = BI
Rule 2: if
Xl
= A21 and X
2
= A22 and Xm = A
2m
then Y = B2
Rule n: if
Xl
= AnI and X
2

= An2 and Xm = Anm then Y = Bn
Facts:
aI,
a2, ,
am
Conclusion B'
6' day: B'
E
{BI' B
2
, , B
n
};
aI,
a2, ,am la cac sv' kien da biet.
HO TRO' qUYlh DlNH CHON NGHE CHO HOC SINH PHO THONG TRUNG HOC
17
Luc do phirong ph ap giai bai toan neu tren bhg suy di~n mer dua tren li thuydt t~p mer voi lu~t
ho'p
th
anh
Max-Mia
qua
cac
biroc
nlnr
sau:
- TInh
di?
thoa

J LB:(Y)
=
min{T
i
,
J LBi(Y)}
- Gia
tri
mer ket qua.
&
dau
ra
h~ thong
J LB'
(y)
13,:
J LB'
(y)
=
max
{J LB'
(y)}
l:St:Sm '
3.2. Cac luat
(tri t.htrc]
Hai rmrci cfiu hoi va nhirng go'i
y
[goi t~t 111.muc tin) co lien quan den huo'ng di
nghf
nghiep ma

ki
hi~u Ii nhorn D gam cac m~c tin: 7, 8, 17.
Nh6m
5: D9ng
CO'
"muon dtro'c di?c l~p, khong phu thuoc trong cuoc song vi tieu dung" - ki hieu 111.
nhorn E, gam cac muc tin 1,
2,
6, 18.
Cae
luat:
• Rule 1:
H (The A motive is Weak)
and
(The B motive is Strong)
and
(The
C
motive is Strong)
and
(The D
motive is Strong)
and
(The E motive is Weak)
then
chon VaGdai h9C.
• Rule
2:
If (The A motive is Medium)
and

va xir
ly
thong tin thu
diro'c
Trong cac lu~t tren
e-
ve trai cac chir A, B,
C,
D, E chi cac bien ngon ngir nhan mot trong cac
gia
tri
me:
Strong [Manh], Medium (Trung binh) va Weak (yeu). D~ d~ dang trong vi~c tinh toan,
hinh dang va gia trj cac ham thuoc ciia cac t~p mer neu tren
duxrc
qui dinh nhir sau:
Strong ,6 hinh dang
ham
thuoc l'
ham tam
giac vuong can ,6 1 [:(]
2
canh gee vuorig b~ng 1, dlnh goc vuong tai di€m (1, 0).
J LStrong(XO) =
Xo Xo
E
[0,1]
Weak co hlnh dang ham thuoc 111.tam giac vuong,
2
canh g6c

if
Xo
=
0,5
2(1- xo)
if
0,5
<
Xo :::;
1
Trong cac hinh tren, true hoanh chi d~ manh yeu cua cac d~ng
CO' thuc
d[y
chon
ngh'e,
true
tung chi gia
tri ham thuoc.
3.4. each giai trong trng dung c\l th~ v
a
vi du
Ta
ky
hieu:
ao,
b
o
,
Co,
do,

cac
m~e tin trong nh6m theo thrr t~':
m~e tin 3, m\le tin 4, m~e tin 12, m\le tin 14, muc tin 16 Ian IU'<?,tla: 0,25,0,05,0,85,0,10,0,15.
Do d6
0,25
+
0,05
+
0,85
+
0,10
+
0,15
ao
=
5
=
0,28
Nh6m B:
Cac
gia tri thu diro'c khi tien
hanh
tr~e nghiern
(y
cac
m\le tin trong nh6m theo thu: t~':
m~e tin 5,
muc
tin 9, m\le tin 15, m\le tin 19 Ian hrot
la:

Cac gia tri thu diro'c khi tien hanh tr~e nghiern
(y
cac muc tin trong nh6m theo thu' t~':
m~e tin 7,
muc
tin 8,
muc
tin 17 Ian hrot la: 0,55, 1,00, 0,05.
d
0,55
+
1,00
+
0,05
0
=
=
°
533
3 '
Nh6m E: Cac
gia
tri
thu diro'c khi tien
hanh
trite
nghiem
&
cac
m\le tin trong nh6m theo

tu:
21,22,23):
- D~ m
anh yi;'u
cua
iro'c muon
vao
dai
hoc
ngay
la:
0,95
t.irc
!LP
l
(e)
=
0,95.
- D~
rnarih yi;'u cua
u'ae
muon dtroc vao
hoc
trtro ng
chuyen nghiep day
nghe la: 0,1 trre
!LP2(e)
=
0,1.
- D~ manh yeu cu a iro'c muon di tlm

1,3,
D;
la gia tri mo cua bien
D
&
lu~t thli'
i, i
=
1,3.
Cac gia tri
Ai, Bi, c.,
Di,
s;
n~m trong t%p {Strong, Medium, Weak}
!LAl (ao)
=
1,0-0,28
=
0,72;
!LBl
(b
o)
=
0,95;
!Le,
(co)
=
0,875;
!LDl (do)
=

=
min{0,56; 0,95; 0,25; 0,533; 0,35; 0,1}
=
0,1
T5ng hop cac d9ng
CO'
thuc d[y va troc muon tlm kiem vi~c lam ngay ciia h9C sinh Ill.
J.Lp;
(15)
=
min{0,28; 0,05; 0,05; 0,875; 0,533; 0,175; 0,1}
=
0,05
Nhir v~y huang di ngh'e nghiep ma hoc sinh co ma so 15 mong muon Ian nhat Ill.VaGhoc trtro'ng
dai hoc hoac cao dhg
J.Lp,(15)
=
max{J.Lp~(15);
J.Lp;
(15);
J.Lp;
(15)}
=
max{0,533; 0,1; 0,05}
=
0,533
=
J.Lp~ (15)
Nh~n tHy d.ng trong thu~t toan tren neu d~t:
T;

111.
J.Lp, (.)
(nh~n
dsro:c
khi hoc sinh trd liri cac cau hdi
21, 22, 23) th anh su'
phu h9'P giira cac yeu to dieu ki~n
(a~ng ca , Ii do, s1! khuyen bdo, hv:o-ng dun)
va
u'ac
muon chu
quan khi chon huang di nghe
nghiep,
Nhir vay:
J.LP; (.)
=
min{Ii,
J.LP. (.)}.
Qua 82 truong ho'p khao sat, trl{c nghiern y kien h9C sinh chung toi nhan thay:
- Doi voi hirong chon
P
1
[vao
h9C dai h9C) thi hau nlnr c6:
J.Lp~ (.)
=
Tl
tro'c muon chu quan vao
hoc tru'o'ng dai hoc cila hau het so h9C sinh d'eu Ion
hen

cling do
J.Lp' ( .)
=
J.Lp~ (.)
V
J.LP; ( .)
V
J.LP; ( .)
nen dh den heu nh tr:
J.Lp' (.)
=
J.Lp~ (.);
nghia
la gan nhir moi hoc sinh deu chon huang di tiep tuc vao hoc cac trtro'ng dai h9C ngay sau khi tot
nghiep ph5 thong. Dieu nay ph u hop
vci
thtrc te, nhung dem ket qui tu vaa cho tirng hoc sinh lai
kern thuyet phuc, vi rnoi hoc sinh deu c6 hiro'ng di nghe nghiep deu rihtr nhau ci: "vao dai hoc la
con du'o'ng duy nh
St",
Tuy nhien hi~u ky y nghia tirng ket qui trung gian trong thuat toan se ph an
tfch va huo'ng dh cho hoc sinh chon hirong di nghe nghiep phu hop thu'c
su:
vo'i bin than
ho'n,
4, PHUO'NG PH.A.P L~P LU~N DUNG HAM DO TREN D~I
SO
GIA TU
4,1.
T~p sinh

Strong)
1\
(E(x),
Weak)
>
((P
1
(x),
Good), True)
• Rule 2:
(A(
z], Medium)l\(
B( x),
Strong)l\(
C(
x),
Mediumj A]
D( x),
Strong)
1\
(E(x),
Medium)
> ((
P
2
(
x),
Good), True)
• Rule 3:
(A(x),

(x),
Good), True) du'Q'c gan
t
nghia: "HQc. sinh
x
titp tuc hoc d~i hoc Ia tgt dgi v6i gia tri
chan It Ia dung" .
Cac m~nh d'e con lai trong cac Iu~t gan
t
nghia bhg each nrong tl!.
4.3.
Bai toan
t5ng quat I~p Iu~
ngon
ngfr dira tren
cac
Iu~t suy di~n c6
dang:
Cho
cac menh
d'e:
(Pdx), olcd /\ (P
2
{x), 02C2) /\ /\ (Pn{x)' oncn)
-+
(P{x), oc)'
aTrue)
((Pda),.Blcl),
True)
((Pn(a), .BnCn),

2 +
~(xo)
+
t
[21°~:1~-
1
*
IT
Sign{O{x
i
))]
J=1 i=1
(2)
v&i
. () {1
neu
a ~
°
SIgn
a
= "
-1
neu
a
<
°
60day
x
=
Xk"'X2Xl Xo

-+
((Pdx),
Oood],
True)
({A{z),.Blcd,
True)
({B{z), .B2C2),
True)
((C(z), .B3
C
3) ,
True)
((D(z), .B4C4),
True)
((E{z),
.Bscs),
True)
+
({P(z),p.d,
True)
6-
day can tfnh gici tri ngon ngii'
P.l
cua
Pdz),
tu:c sl! phu ho'p cua h9C sinh
z
chon hurrng vao dai
h9C•
4.4. D€ tfnh gici tri ngon ngir

+
({A(z),cJ),.BJTrue)
HO TRQ" qUYlh f)~H CHON NGHE CHO HQC SINH PHO THONG TRUNG HQC
21
CJ
E {Weak, Medium, Strong},
(3J
la day cac gia tli-,
M~nh d'e
((A(z), cJ), (3JTrue)
mang y nghia la d9 manh yeu cua d9ng co' ngh'e
A
anh hirong Mn
hoc sinh x la
CJ
(ygu, Trung blnh, Manh], qua td.c nghiern thu dtro'c gia
tr]
ao
di'eu d6 c6 gia tr]
chan ly la {3J True ({3J la day cac gia tu:) ,
Theo y nghia ham thu9C ta co the' gan tri nhir sau:
A({3.rTrue)
:=
J1.CJ
(ao), CJ
E {Weak, Medium, Strong}
Theo cong thirc (2) suy ra:
A({3JTrue)
=
A({3J)

A(J1.3)
=
0,75 + 1/5[(J1.strOng(ao) + J1.weadbo) +J1.Strong(CO)+ J1.Strong(d
o
) + J1.Strong(eo) - 3,75)]
Doi voi dir li~u ctl.a hoc sinh 15: A
(J1.i),
i
=
1, 3 tinh ra diro'c ket qui nhir sau:
A(J1.1)
=
0,7806
-+
Mire d9 phu hop ciia hiro'ng di dai hoc cua hoc sinh 15 la 0,7806
A(J1.2)
=
0,5287
-+
Mire d9 phii hop cua hurmg di hoc trtrong day nghe cu a hoc sinh 15 la 0,5287
A(J1.3)
=
0,3287
-+
Mire d9 phii hop cua hirong di tlm vi~c lam ngay cua hoc sinh 15 la 0,3287
5.
KET QUA THVC
NGHI~M
Dira tren cac thu~t toan xu' ly thong tin neu tren, chirong trlnh t\l' d~mg xli- ly thong tin b~ng
may tfnh cho h~ tro' giiip quydt dinh chon hmrng di nghe nghiep dtro'c viet bhg ngon ngir C,

101.
khuyen lai rat phfin
khoi va xin diro'c trl{c nghiem lai de' nh an ket qua. va lai khuyen xac thirc ho'n.
Chon hircng di nghe nghiep khOng chi chti y Mn nguyen vqng chii quan ma con phai can err vao
cac ygu to dieu ki~n khac nhir nang hrc, sO-tru'cng, hoan canh gia dlnh, su' khuyen bao cua cha me,
thay giao v,v Tren CO' sO-so sanh cac rnp; va MPi hoc sinh se e6 str ke't hop giira cac yeu to chii
quan [cac mp;) va cac yeu to khach quan t.ac d9ng (Mpi),
Nha trtro'ng e6 hoc sinh tham gia td.e nghiem vui mimg d6n nhan ket qui va eoi d6 la phan
m'em tro' giup cong tac giao due huang nghiep cho hoc sinh, dong thoi hua phdi hop theo d6i suo
dung, ph an tfch ket qui de' di'eu chinh lam eho h~ thong hoan thien hen.
22
YU
MINH
LOC
6,
DANH GIA,
KET
LUAN
Qua bai bao nay chiing t8i da giai thi~u kgt qua thuc nghiern cua 2 phiro ng ph ap suy di~n mer
dua tren ly thuydt t~p mer vo'i lu~t hcp thanh Max-Min va dung ham do tren dai s6 gia tt d€ hlnh
thanh h~ tro' giup quyet dinh chon hircng di nghe nghiep cho h9C sinh sau khi t5t nghiep ph5 thOng
trung hoc. Do tien hanh dong thoi 2 phtro ng phap nen c6 dieu ki~n ket hop cac kgt qua da dtra ra
lai khuyen cho hoc sinh xac thu'c han nhir da trmh bay 6-tren. NhU' v~y vi~c ket hop 2 phurrng ph ap
cho phep han che nhirng nlnro'c difm cu a tirng phtro'ng ph ap va tang cirong U'Udifm cua chung ,
Ngoai ra ket qua. thirc nghiern con dua tren nhirng
U1l
difm sau day cua phirong ph ap tien hanh:
- Phuo-ng phap triic nghiern
de'
thu nhan thOng tin bhg h~ th6ng cau hoi va tr.i. lai bhg danh

[3] Kofi Kissi Dompere, The theory of Approximate prices: Analytical foundations of experimental
cost-benefit analysis in a fuzzy - decision space, Fuzzy Sets and Systems 87 (1987) 1-26.
[4] Nguy~n Cat
Ha,
Xay dung each tiep c~n dai s6 den logic me)' va l%p lufin xap xi, Btio ctio
Hoi
nghi khoa hoc Gong ngh~ thong tin nghien cuu va trie"n khai.
[5] Nguyen Cat Ho, A method in Linguistic Reasoning on a knowledge Base Representing by
sentences with Lingristic Belief Degrre, Fundamenta Informaticae 28 (3) (1996) 247-260.
[6] Nguyj n Cat
Ha,
Huynh Van Nam, Min h6a dai s6 gia tli' du'a tren cac dan ph an phdi tlJ.' do
sinh b6-i cac gia tti:, Bdo ctio Hoi nghi khoa hoc cong ngh~ thong tin nghien cU'u va tritn khai.
[7] Phong Nghien
ciru img
dung cong ngh~ cac chuyen gia va h~ h6 tro quyet dinh, Vi~n Cong
nghie thong tin,
Ha
So' ky thu~t de tai TT97.09.
[8] Ron Sun, Commonsense reasoning with rules, cases and connectionist models, A Paradigmatic
comparison, Fuzzy Sets and System 82 (1986) 187-200.
[9] Toshiyuki Yamashita, On a support system for human decision making by the combination of
fuzzy reasoning and fuzzy structural modeling, Fuzzy Sets and System 87 (1987) 257-263.
[10] Tran Dmh Khang, Xay dung ham do tren dai so gia tli' va irng dung trong l~p luan ngon ngir,
Tq.p cM Tin hoc va oa« khie"n hoc
13
(1) (1997) 16-30.
[11] Yan Shi, Masaharn, Reasoning conditions on K6zy's in terpolative reasoning method in Sparse
fuzzy rules bases, Fuzzy Sets and System 87 (1987) 47-56.
Nh4n bdi ngay 5 - 1 - 2000