Qua trlnh ch[n dean lam sang ngtrci b~nh la qua trlnh thOng thiro'ng diro'c tlnrc hien bO'i t~p th~ cac chuyen gia y hoc.. Trong qua trlnh ch[n dean, m~i chuyen gia y hoc se dtra VaGtri~
Trang 1T~p chl Tin hocvaDi'eu khi€n hoc, T.16, S.l (2000), 52-58
LAM SANG
DO VAN THANH
Abstract The main purpose of this paper is to present an approach for applying aggregation model
in possibility theory proposed in the papers [3 - 8] in processes of clinical diagnostics with participation
of many medicine specialists
Qua trlnh ch[n dean lam sang ngtrci b~nh la qua trlnh thOng thiro'ng diro'c tlnrc hien bO'i t~p th~ cac chuyen gia y hoc Day 111khfiu bitt bU9C va anh hircng quan trong dgn chat hro'ng di'eu trio
M\lC dich cua qua trlnh nay nh~m xac dinh dung benh, rmrc d9 mitc b~nh ciia ngtro'i b~nh va dira ra bi~n phap dieu tri ban dau
Trong qua trlnh ch[n dean, m~i chuyen gia y hoc se dtra VaGtri~u chimg Him sang ngtroi b~nh, dira VaG tri th irc y hoc chung da diro'c t5ng ket va dira VaGtri tlnrc kinh nghiern cua chinh mlnh d€ dua ra y kign ch[n dean
Nhieu tlnh huang xay ra la ngirci b~nh bie'u hi~n lam sang khong ro net, nhirng chuyen gia y hoc chi co th~ dira ra nhirng ph an dean rieng cua mlnh va ni"em tin VaGsir dung dJtn cua cac phan doan rieng ay cua m~i chuyen gia n6i chung Ill.khac nhau Trong nhirng trtronghop nhu v~y ta can phai chon y kign cua chuyen gia xuat s;;'c nhat ho~c t5 hop cac y kien ciia cac chuyen gia do de' dira
ra m9t ch[n doan lam sang tot nhat c6 the' dtro'c cho ngiro'i b~nh
Bai bao nay se chi ro d.ng cac phan i1.oan chv:a chif.c chif.n ve lam sang ngiro'i b~nh se tao thanh
m9t CO" sO-tri thu:c gia tr~ can thiet (ho~c khd nang) trong 111 thuyet khd nang Bo-i v~y ta c6 the' irng dung phircrng phap hra chon ho~c phtrong phap tich hop cac y kien chuyen gia dC>ivo'iCO" so' tri thtrc trongIy thuyet kha nang da diro'c de xuat trong cac tai li~u [3-8].
Bai nay chi trlnh bay han chg mot khia canh img dung cii a phtro'ng ph ap tkh hop thong qua vi~c gi&i thi~u mf hlnh tfch hop trong ch[n dean lam sang ngtrci b~nh
Gii sd' c6 m chuyen gia y hoc tham gia thu'c hi~n ch[n dean lam sang nguoi b~nh M~i chuyen gia thirong dira ra cac y kien phan dean cua rninh dirci dang t~p cac cau kie'u nhir:
1) Co the' tin rhg (cUc chh rhg) ngiroi b~nh co chirng.b~nh [hoac ngtrci b~nh can diro'c]
"ten cac ket lu~n" •
2) VInguei b~nh co cac trieu chimg "ten cac tri~u clnrng" nen co the' tin rhg (cUc chh rhg) ngtroi d6 co chirng benh [hoacngiro'i do can diro'c] "ten cac ket luan".
Sau d6 t~p the' cac chuyen gia se phan tfch tat d cac phan doan d6 de' rut ra cac phan do an thkh ho'p nh St; Truong hop khi bie'u hi~n lam sang ngtroi b~nh khong ro net ho~c co nhieu bie'u
3) C6 nhieu kha nang tin rhg (gan nhir chdc chdn d.ng, kha cUc cMn rhg, ).ngtro'i b~nh
co chirng b~nh (ho~c ngiro'i b~nh nen diroc] "ten cac ket lu~n", ho~c la:
4) VIngiro'i b~nh c6 cac tri~u clurng "ten cac tri~u clnrng" nen co nhieu kH nang tin r~ng ( gan n ir c ac c an rang, h h~ hd •• kh'a c ac c an rang, hoJ h6 ~ ) ngucn, •d'0 co c trng, h' bA h (hen oac ngtrmv , d'0 nenAd)iro'c
"ten cac kih lu~n".
Trang 2Trong nhirng ket luan kie'u nay, cac ti nhir: co nh ieu khd nang, g n n hv : c h ;{ c cMn, k lui cMc
h" • ~ th" hi A At khf h" h~ "', h d' d" , , h' d' ~" A
d6
3.1. SO' do qua trinh cha?ndoan
dt sau
2 se lo ai b3 nhfi:ng phan doan v ly kh6 e6 the' chap nhan, nhirng phan doan dir thira Giai dean 3
Trang 354 DO VAN THANH
phan doan cung cap cho qua trinh chin doan tiep theo
3.2 M6 hinh tich h<!p
du'cc tien hanh theo ht rng tep c~n tien de h6a va diro'c thuc hi~n tren cac phan bo kha nang d~c
-r = {Si, i = 1, , n} Ia t~p cac phan dean xac dang dtro'c xac dinh trong giai dean 2 [tlnrc chat
doi voicac cau trong r.
Vi~c tfch hop cac y kien chuyen gia kigu nhir y kien chuyen gia F diroc thirc hien tren cac
( o ng , Ton trqng tr~t ttf Lay y hen , Loei trv: stf khcic bi~t
• Ma hmh nay thirc chat Ia me tsu' khai quat hoa md hlnh vira diro'c trinh bay tren Neu nhu
mo hmh tren nh~m gicl.i quyet van de rich hop cac y kien chuyen gia, o'do ta chira quan tam mdt
nluiu (hay Likewise)" Mgicl.iquydt van de mo-r9ng nay Trong [9] chung toi con chi ra r~ng khi quan
hai cang do~n:
a =<I>(a 1'a2 , , am)
Trang 4trong do
m
i= .>1 J
J_
6-day m la s5 chuyen gia eha:n dean, PiE [0,1] vo'i moi i= 1, , m
Tinh chat cua toan tu'nay dii diro'c chi ra trong [10], ev the' la no thoa 7 di'eu ki~n doi hoi eho cac qua trlnh tieh hop "Chi ph1f thuqc stf ki4n" cda cac phan bo xac xuat,
4 vi DlJ MINH HQA (J day chi trmh bay vi du minh hoa qua trlnh eh.in doan sau khi ket thuc giai doan 2, tu-e la
dii xac dinh diro'c t~p cac ph an doan xac dang cila t~p the' cac chuyen gia tham gia eh.in dean Gia su'cac phan doan do la nhu sau:
81: Neu tn~ em bi suy dinh dufrng thl kha ehite ehltn rhg dira tr~ da vang, bung ong, bieng an 82: Neu tr~ em bi da van , bung ong, bieng an thi ttrong d5i eUe ehltn r~ng dii'a tr~ bi gan yeu
83: Neu diia tr~ bi suy din dufrng, nhirng dai tie'u ti~n rat tot thl gan nhir ehlte ehltn rhg dira tr~ khong mite b~nh ve gan
84: Chlte ehltn rhg dira tr~ bi suy dinh dufrng
85: Gan nhir ehite ehltn d.ng CO" quan dai tie'u ti~n cua dira tr~ tot,
Th~t ra t~p cac ph an dean "nay la m9t Sl!:bien the' tIT m9t vi du cua Dubois va Prade [ 2 ] , di
dircc nghien ciru phat trie'n trong [7],
D~t: a = "dira tr~ bi suy dinh dufrng": b = "du-a tr~ bi da vang, bung ong bieng an"; c =
"dira tr~ bi gan yeu"; d = " o"quan dai tie'u ti~n cua dira tr~ t5t",
Khi do cac ph an doan tren dircc viet dum dang
81 :-'a V b; 82 :=b vc; 83 :-,a V -cd v-,c; 84 :a ; 85 :d
va t~p cac loop the gi&i co the' diro'c sinh ra tu: t~p cac phan doan nay se gom co: WI = (a, b ,c,d);
Giai doan 3: Thu th~p y kien danh gia cua c'ac chuyen ·giave t~p cac phan doan
Gia.su' 7 chuyen gia tham gia eh.in dean eho cac y kien cda ho ve rmrc de? ean thiet doi v&i tinh trang dung ciia cac phan doan tren diroc me ta.tron ban 1
B dng 1 Ykien cua cac ch yen gia
(8d (82) (83) (84) (8 s )
Fs 0,70 0,50 0,70 0,20 0,50
Trang 5Theo phiro'ng phap xay dirng phan be kha nang d~e d it nhilt dei vai mt)i y kien d nh an tren,
ta se nhan diro'c cac ph an be kH nang' d~e d.it nhat ttrcrng ling (being2)
Bdng 2 Being cac phan b9 kha nang d~e trtrng eho cac y kien chuyen gia
FI 0 , 20 0,80 0 , 50 0 , 40 0 , 20 0 , 30 0,30 0,30 0 , 50 0,50 0,40 0,40 0,40 0,40 0,40 0,40
F2 0, 30 0 , 70 0 , 50 0 , 40 0 , 30 0 , 35 0,35 0,35 0,50 0,50 0,40 0,40 0,40 0,40 0,40 0 , 40
F 3 0, 2 0 , 80 0 , 6 0, 4 0 , 25 0 , 40 0 , 40 0 , 40 0 , 60 0 , 60 0 , 45 0 , 45 0,45 0,45 0 , 45 0,45
F 4 0, 4 0, 55 0 ,70 0,55 0 , 40 0, 40 0 , 40 0, 40 0, 70 0, 55 0 , 3 0 , 30 0 ,60 0 , 55 0 , 60 0,55
Fs 0 , 30 0,50 0, 8 0 , 50 0,3 0 0 ,3 0 0 , 3 0, 3 0, 8 0 , 5 0, 2 0, 2 0, 7 0, 5 0 ,7 0 0,50
Giai doan 4: Tich h<!pY kien chuyen gia
a Tich ho'p phan b~e theo cac 16"pco cung thu tv tv nhien (lien ket veri mqt loos todn ttt)
Gici suor~ng ta chon toan tu ton tronq 11kien so il,ong!Pr m la toan tu' lien ket v6i.qua trinh tich hop phan b~e nay
Ky hi~u 1ra gg la y kien tich hop diro'c sinh ra bch qua trinh nay, khi d6
1r a g g=!Prm (!prm (1rF, (~) , 1rF, (w) , 1rF (w)) , !Prm (1rF (w) , 1rF (w), 1rF6 (w) )!prm (1rFT (w)))
v i moi lap the' gi6i.e6 thi w.
D~t 1rdw) = !Prm(1rF, (W),1rF,(W) , 1r F (W)) va 1r2(W) = !Prm(1rF.(W) , 1rF.(W) , 1rF 6 (w)), khi d6 ta nhan diroc bang minh hoa cac phfin be 1r1, 1r2, 1rFT' 1ra g sau day:
1r1 0,30 0, 8 0, 5 0,4 0 0,5 0 0,40 0 , 40 0 , 40 0 , 50 0 , 50 0 , 40 0,40 0 , 40 0,40 0,40 0,40
1r2 0 , 40 0, 55 0, 70 0 , 55 0 , 40 0,40 0 , 40 0 , 40 0 ,70 0,55 0 , 30 0 , 30 0 ,6 0 0,55 0,60 0 , 55
1rFT 0 , 35 0,50 0 , 75 0 , 50 0,40 0 , 40 0 , 40 0,40 0,60 0,50 0,35 0,35 0,60 0,50 0,60 0,40 1r agg 0 , 40 0 , 80 0 , 75 0 , 55 0,40 0 , 40 0,40 0,40 0,7 0 0, 50 0 ,40 0,40 0 , 60 0 , 55 0 , 60 0,40
Vi v~y trong truong hop nay y kien tich hop tir 7 y kien tren ve cac phan doan d~ cho la: (S1, 0,6) ,
b Tich h<!p phan b~c theo cac 16"pco cling d(J mau thu.5.n (lien ktt vo - i mqt loai to an ttt)
Toan tu diroc lien ket voi qua trinh tich hop phan b~e nay toan tn-ton trqng thti: ttf !Pr o , trong d6 cac ham h;(x) diro'c xac dinh nhir sau:
{ ° neu x :~ :;1 - -:-1
x neu 1 ~ x > 1 - r:
Ta c6 th~ thjra nhsn rhg trong qua trinh thu nh~n tri thirc, vai hai y kien bat ky, y kien nao e6 d9 mau thuh nho hon se diro'c coi 111.quan trong hon va dircc U'U tien thu nh~n truxrc Bay gi<r gia suo1r : gg la ky hi~u cua ph an be ket qua nhan diro'c tir qua trinh tich hop phan b~e lien ket vai toan tu !Pr o &tren, khi d6 1r:gg diro'c xac dinh boi
1r: gg (w) = !pr o ( e , (1rF, (w) , 1rF (w) , 1rF (w)) , !Pr o(1rFT (w)) ' !Pr o(1rF, (w) , 1rF (w) , 1rF6 (w)))
v6i.moi lap the gi6i.c6 th~ w
Trang 6D~t 7rr { W) = <1>r o (7rFl(W) , 7rF3(W) , 7rF S (W)), 7 r 7(W) = <1>r o (7rFr(W)) ,
7 r ;(W) =< 1 > r o (7rF2 (W) , 7rF (W) , 7rF 6 (W)),
khi d6 ta nh an dtro'c bang sau:
7r*1 0,20 0,80 0,80 0, 40 0,20 0 ,30 0,30 0,30 0,80 0,60 0,40 0 , 40 0,70 0,40 0,70 0,40
7r7 0,35 0 , 50 0,75 0,50 0,40 0,40 0,40 0,40 0 , 60 0,50 0,35 0,35 0,60 0,50 0,60 0,40
7r*2 0,30 0,70 0 , 70 0,55 0 , 30 0,35 0,35 0 , 35 0 , 70 0,55 0,40 0,40 0,60 0 , 55 0,60 0,55
7r ;gg 0 , 20 0 , 80 0 , 80 0 , 40 0 , 20 0 , 30 0,30 0,30 0,80 0,60 0,40 0,40 0,70 0 , 40 0 , 70 0,40
Tir bing nay ta nhan dtro'c y kien tich hop F :gg : (81, 0,8)' (82, 0,2), (83, 0,8), (84, 0,2),
(85 , 0,2)
c Tich hqp phan b~c lien ket vOi hai toan
tu-Neu ta chon <1>1 =<1 >rov&i cac ham hdx) diro'c xac dinh nhu o' phan tren va <1>2 =<1> rm Gia stt·
7r~gg la pha bo tich hop ket qua cua qua trlnh tich hop ph an b~c lien ket v&i cac toan tu- <1>1, <1>2
Ta c6 7r~gg(W) = <1>r o (7rdW) , 7rFr(W),7r2(W))' va ta c6 bang sau:
Wl W2 W 3 W4 W5 W6 W7 Ws Wg WID wll W12 W13 W14 W1 5 W1 6
7r~gg 0,30 0,80 0,70 0,40 0,50 0,40 0,40 0,40 0,70 0 , 50 0,40 0,40 0,60 0,40 0,60 0,40
Vi v~y ta nhan diro'c y kien tich hopF~gg : (81 , 0,5)' (82, 0,2)' (83 , 0,5), (84, 0,3), (85, 0,2)
130 phan doan chung cii a t~p th~ chuyen gia Ch1ilg han "aua - tre bi gan ylu" la mi?t trong cac phan dean c6 th~ suy di~n dtro'c tir cac phan dean n6i tren
[diro'c mo tA?ycac bang 1, 2) ta nh~n diro'c rmrc di? can thiet it nhat d~ "au a t r e b; gan ylu" ttro'ng iing vo'i 7y kien chuyen gia d6 u0,6; 0,6; 0,55; 0,4; 0,3; 0,4; 0,4
ki~n so dong, thi theo y kien nay mire di? can thiet it nhat Mphan doan "aua t r e bi gan ylu" khOng nho ho'n 0,2
Neu y kien chung dtro'c sinh b&i qua trinh tich ho'p ph an b~c lien ket vo'i toan td- ton trong thii' tu, thi theo y kien nay rmrc di? can thiet it nhat Mphan doan "aua tre bi gan ylu " khOng nho hon 0,3
Neu y kien chung diro'c sinh b?Yiqua trlnh tich ho'p ph an b~c sd-dung h~n hop hai loai toan td
-tich hop la toan td- ton trong y kien si 5 dong va toan td- ton trong tlur t~, thi theo y kien nay mire di? can thiet it nhat Mphan dean " a a tr e bi gan ylu" khOng nho hon 0,4
tri tlnrc day dil, chitc chitn cila chuyen gia dii dtro'c quan tam nghien CU:u tir cuoi th~p k170 va dii c6
co san phitm thiro'ng mai chfnh thirc m~c du n6 du'oc quan tam nghien ctru rat manh trong vai narn
Trang 758 DO VAN THANH
g~p trirong hop co ngiro'i b~nh mitc phai nhirng c n b~nh it khi xay ra, th~m chi co d tr cng hop
ngtro'i b~nh mi{c phai can b~nh mo'ixuat hien, Ltic do c~n thi~t co nhieu ch yen gia y tg tham gia
ch[n d an lam sang ngiroi b~nh, va noi chung trong nhirng trtrong hop nay tri thirc, kinh nghiern
cia m6i chuyen gia tham gia ch~n doan thuong ciing khc3ng d~y dli va khong chltc chh v"ecan b~nh
do Nhirn n hien.crru dircc trmh bay trong bai b3.0 nay d~c bi~t thich hop khi g~p phdi nhfmg tinh
hudng nhir v~y Tuy nhien no ciing co th€ drroc sU:dung cho nhimg truong hop chi co m9t ngufri tham gia cha:n doan ho~c khi cac chuyen gia tham gia cha:n dean co tri thirc, hi€u bi~t d~y dli, chitc
chltn vE;tri~u chirng lam sang cua nguoi b~nh do
Plnrong phap giai quy~t giai dean 2 trong 5 giai doan noi.tren ciing da.dtro'c nhieu tac giA nghien ctru va noi chung da.co th€ hinh thanh phtrong phap Mgiai quygt cho giai doan nay
.Nhirng ket qua trinh bay trong bai b3.0 mei dircc dimg armrc d9 nghien ciru CO" ban D€ xay
dung m9t h~ tro' giiip quyet dinh C1;1 th€ theo each tiep c~n dtroc trinh bay a tren, chd yeu phai giai quyet m9t so van dE;con lai nhir: xac dinh vimg irng dung thich hop trong y h9C va nghien ciiu t5
clnrc xay dung phan mern
[1] D Dubois, J Lang, H Prade, Possibilistic Logic, Handbook of logic in Artificial Intelligence
Dov M Gabbay, C.J Hogger, J A Robinson, D Nute, Clarendon Press, Oxford, 1994,
438-510
[2] D Dubois and H Prade, Epistemic entrenment and possibilistic logic, Art i fic i al Intell i gence
50 (1991) 223-239.
[3] D V Thanh, A relationship between the possibility logic and the probability logic, Computer
[4] D.V Thanh, Stability of the principle of minimal Specificity and maximal Buoancy, Tq.p cM
[5] D.V Thanh, Application of Stability of the principle of minimal Specificity and maximal Buoancy, accepted for oral presentation in The Joint Pacific Asian Conference on Expert
1 97
[6] D.V.Thanh, Aggregation of distributions and Aggregation operators, Top cM Tin hoc va Dieu
kh i e ' n hoc 12, No.3 (1996) 47-63
[7] D.V Thanh, Hierarchical Aggregation of Possibility Distributions, Proceedings of the National
[8] D6 Van Thanh, Phuong p ap l~p lu~n tren cac co'so' tri thU:c co nhieu danh gia kha n au,
Tuye' n t~p cac bti o c t o kh oa hoc ky ni~ m 2 n i im th anh l ~p Vi~n C ong ng h 4 thong t i n T 12,
1996, 403-418
[9] D V.Thanh, Possibility Consensus Model, Proceedings of Japan - Vietnam Bilateral Symposium
[10] D6 Van Thanh, Posibility distribution's aggregation via probability model, 1997, to appear in
[11] D.V Thanh, Posibility Information Measures and Selection Approach, Computer and Artificial Intell i gence 18 (6) (1999) 595-610.
Nh4n bai ngay 12 - 7-1 998
Van phong Ban cM doo ChuO'ng trinh quoc gia