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PLoS Neglected Tropical Diseases, 5 (8): el258 doi:10.1371/joumal.pntd.000 1258
Tdm tat
Tdng quan
Vi4c su dung cdc dit li4u tlm kiim trin mgng internet dd duoc chiing minh Id cd hi4u qud trong vi4c du dodn ty 14 mdc cum. Cdch tiip cdn ndy cd thi thdnh cdng hon trong nghiin cwu b4nh sdt xudt huyit mdtyl4 mdc mdi hdng ndm cd su thay ddi l&n vd biiu hi4n rd hon vi Idm sdng vd phuong thuc ldy truyin,
Phirong phdp
Chiing tdi thu thdp dit lifu ty 14 mdc b4nh sdt xudt huyit cd sdn & Singapore (ty 14 mdc hdng tudn, tit 2004 - 2011) vd & Bangkok (ty 14 mdc hdng thdng, 2004-2011). Dit li4u tlm kiim tie Internet da timg th&i ky dd dugc tdi vi tir Google Insights. Dieu ki4n tlm kiem dugrc chpn phdi phdn dnh dugc ha tiiu chudn liin quan din b4nh sdt xudt huyit: danh phdp (nomenclature), ddu hi4u/tri4u chimg vd diiu Irj. Chdng tdi so sdnh ba md hlnh didtf dodn ty 14 mdc m&i: hdi quy ngugc hu&ng ti4m cdn , hdi quy ddng biin tdng quan, vd hSi quy nhi thuc dm. Si dung hdi quy logic vd md hlnh hd trg Vector (Support Vector Machine - SVM) di du dodn ket qud nhj phdn, cho da ty 14 mdc b4nh sdt xudt huyit cd vugt qud ngudng dd chpn hay khdng. Ddnh gid md hlnh dtf bdo ty 14 mac mdi bdng cdch ste dung h4 sd tuong quan r^ vd test Pearson giiia du dodn ty 14 mdc m&i sdt xu& huyit vd quen sdt. Md hinh Logistic vd SVM dugc ddnh gid b&i di4n ttch du&i du&ng cong ddc trung dang tdn tfd(AUC). Mb hinh dugc xdc nhgn bdng cdch su dung nhieu kp thudt xdc nhgn qua gid tri diim cdt.
Kit qua
Cdc md hinh tuyin tinh dugc lua chpn b&i AIC ngugc hu&ng thdy rdng tdt hon cdc md hinh khdc. Tgi Bangkok, md hinh sie dung Id r' = 0,943, vd mdi tuong quan Id 0,869. Tgi Singapore, md hinh sii dyng Id 1^ - 0,948, vd mdi tuong quan Id 0,931. Oca Singapore vd Bangkok, md hinh SVM vugt trdi so v&i hdi quy logic trong vi4c du dodn thoi 1^ cd ty 14 mdc cao. AUC cho cdc md hinh SVM sie dung cdt 75% Id 0,906 & Singapore vd 0,960 & Bangkok.
Kklu^
Cdc thudt ngit tim kiim trin Internet di du dodn ty 14 mic vd th&i kp bOng phdt sSt xudt huyit vdi dg chinh xdc cao vd cd thi chung minh Id chdng hitu Ich trong cdc khu vi/ec cd h4 thong gidm sdt kim phdt trim.
Cdc phuong phdp trinh bdy & ddy Id su dung dit U4u miin pht vd cdc cdng cu phdn tich vd cd thi diddng thich nghi v&i cdc thiet ldp khdc.
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Google da ghi nhgn trong vipc su dyng cdc thudt ngii dugc n h ^ vdo cdng cy tim kiem cua minh (www.google.com) Id thdnh cdng de dy dodn khd ndng xdy ra dich ciim theo ghi nhgn hdng tuin cua Trang tdm Phdng chIng Dich bpnh Hoa Ky (CDC-My) ciia cdc trudng hgp mdc bpnh vd ty 1| tir vong tir 1-2 tuin. MOt s6 nghiin cihi da bdo cdo kit qud tuong ty de gidm sdt ciim bdng cdch sir dyng cdng cy tim kiim dft lipu Google, dCi lipu tim kiem cua Yahoo, vd qudng cdo trin internet. Nghiin cuu cua Google cho t h ^ rdng, khi ty Ip mdc ciim hdng tuan tdng hodc giam, kit qud cua mgt s6 ttiu$t ngii tim kiim trin internet trong ciing m§t khu vyc dia ly thay doi vdi mgt miic dO cao ciia sy tuong quan vd kha ndng dy bdo. Sii dyng kha ndng thdi gian thyc thu thgp cdc dii lipu (trong vdng 24 gid, trdi ngugc so vdi tit 1 din 2 tuin trong bdo cdo ciia CDC My), cdc nhd nghien cihi da cd till dh cd dugc tiidng tin ve xu hudng cua md hinh xay ra dich ciim mgt cdch ldp thdi hon so vdi gidm sdt trayin thong.
S6 5 - 2011 TAP CHl P H 6 N G CHONG BgNH S6T R§T V A C A C BgNH K^ SINH TRONG 23
Mac dti nhihig nS lye diu tien sii dyng cdc thugt ngOr tim kiim tir www.googIe.com da tgp trung vdo bpnh ciim, bpnh hgc cua nd cd till Id mgt trong nhOmg khd khdn hon dl dy dodn bdng cdch su dyng tim kiim Internet. Biiu hipn bpnh hpc ciia ciim khdng cy thl vd tim kiim mdt ngudi mdc blnh ciim cd thl nhim lan vdi cdc tradng hgp mdc bpnh khdc. Bpnh hpc thl hipn cdc diu hipu lam sdng khdc bipt dugc md td bdi cdc bpnh cy thl dugc sii dyng rgng rdi bdi dan so ndi chung cd the biiu hipn moi tuong quan rd rdng vl tim kiim vdi ty 1| mdc blnh.
Ngodi ra, du bdo ty Ip mdc quan trgng hon doi vdi cdc tdc nhdn gdy bpnh cd biiu hiin thay dii mgnh me theo thdi gian. Sot xuit huylt biiu hipn cd hai ddc dilm ndy: tripu tning lam sdng biiu hipn rd rdng hon so vdi ciim, 1dm tdng dieu ki|n bpnh cy thl vd ty Ip mdc bpnh sot xuat huylt tgi nhilu dilm dieu tra vdi biin d^ng Idn ciia ty II mdc mdi khdc nhau tir ndm ndy sang nam khdc trong 10 nam quan sdt.
Vi nit sot xuit huylt Id vi nit do muoi trayin thupc hp Raviviridae, bao gom 4 typ huyet thanh khdc nhau. Nd dugc lay trayin qua vlt dot cda muoi da nhiem bpnh {Aedes aegypti Id moi de dog 1dm nhat doi vdi con ngudi) vd ngudi nhiem bdi mpt trong bon typ huylt thanh khdng mien dich chIo vdi typ huyet thanh khdc. Thdi ky u blnh thudng Id 4-7 ngdy vd cd thl biiu hipn sot khdng diln hinh, nhu sot phdt ban, dau dau, dau co vd khdp. Cdc bieu hipn lam sdng ndng, sot xuat huylt dengue (DHF), liln quan chdt che vdi cdc ca nhiem thii cap vd khoang 3% cdc trudng hgp mdc.
Dy dodn sy bimg phdt viras sot xuit huylt d cdc quoc gia vdi he thong gidm sdt kim phdt triln Id rit quan trgng cho cdc BdY tl vd y tl Cdng cgng trong viec dua ra cdc quyet dinh, noi thudng bi hgn chi bdi ngan sdch hodc quyin hgn cua minh. Biiu hipn lam sdng ciia blnh sdt xuit huylt, mac dti rit giong cdc blnh khdc, ddc bipt Id blnh ciim, vd nhieu thudt ngii:
tim kiim ma cdc cd nhan cd thl tim kiim khi tim kiim thdng tin vl blnh sot xuat huylt cy thl ddi vdi blnh sot xuit huylt (nhu trdi ngugc vdi cym tir nhu Id "Ignh"). Vi vdy, tim kiim trin Intemet cd thl biiu hipn mdi tuong quan mgnh me hon vdi ty 11 mac bpnh sdt xudt huyet hon Id ciim. Dy dodn chfnh xdc ty 11 mdc blnh sot xuit huylt Id dl nhdm din myc tiiu hilu qud hon cdc bien phdp phdng chdng nhu phdng chdng vector vd gidm tdi blnh nhdn trong blnh vipn, lam tang nhanh chdng cdc dy doan xdy ra sdt xudt huyet trong khu vyc cd he thdng gidm sdt kim phdt triln.
Tgi Thdi Lan, blnh sdt xuit huylt dugc xem Id bpnh cd ty 11 mdc vd gay tir vong cao trong 70 nam qua. SJOI lan diu tiin dugc phdt hipn d Bangkok vdo ndm 1949. Bd Y tl Thdi Lan da tiin hdnh gidm sdt bpnh sdt xuit huylt kl tir nam 1968. Ty 11 mdc tgi Bangkok khdc nhau giiia cdc nam tii 15.000 blnh nhan din hon 175.000 blnh nhdn vdo moi nam. Tgi Singapore, SXH Id mdt nguyin nhdn quan trpng |dy tir vong d tre em trong nhfing ndm 1960, 1970 vd 1980, qua do nhfing no lye gidm mdc bdng cdch phdng chong vector nhu 1dm gidm noi de tning ciia muoi Aedes, 1dm giam nhanh chdng ty Ip mdc SXHD trong cuii thgp niin
1980 vd diu nhfing nam 1990. Tuy nhiin, tir cuoi nhfing ndm 1990 trd di, tinh hhih sot xuit huylt cd diu hipu bung phdt mgnh trd Igi mdc dti mat do mu5i Aedes thip, dinh dilm Id vy dich Hch sii dugc ghi nhgn Idn nhit tgi Singapore nam 2005 cd 14.000 tradng hop mdc. Mac dti xu hudng tang trong thdi gian giiia ndm, nhung cd sy biin ddng Idn vl ty 11 mdc hdng tuin tir 32 din 713 blnh nhdn trong giai dogn 2004 - 2011.
Khd nang dy dodn chfnh xdc su gia tdng ty Ip mdc se huu fch dl tiin hdnh mdt logt cdc bien phdp can thiep 1dm sdng (triln khai cdc dpi y tl, vp sinh giudng blnh trong blnh vipn), vd cdc can tfiilp ti-ong y tl cdng cdng (tang cudng gidm sdt, gido dye y tl cgng ddng vd cdc
24 TAP CHf P H 6 N G C H 6 N G BgNH S 6 T RJT vA cAC BgNH KY SINH TRONG S 6 5 - 2011
bipn phdp gidm noi dl ciia mu5i) dl gidm Idy tiuyln b|nh sit xuit huylt. Thudt ngft tim kiim trin Intemet dya trin gidm sdt cd thl Idm gidm sy chdm trS liln kit vdi cdc h | tiiong gidm sdt trayen tiling vd h | tiling h5 trg kim phdt triln.
2. PHlTONG P H A P NGHlfeN CtfU Dir lipu cdu hdi tim kiim
DO: li|u tim kiim dugc tdi vl tir trang tim kiim cda Google
(http://www.google.com/insights/search/) vdo ngdy 18/02/2011 d Singapore vd 02/03/2011 d Bangkok. Cdc thudt ngfi: tim kiem cd liln quan cho cd hai dd dugc lya chgn Id cdc tir thudng dugc sd dyng trong vi|c tim kiim cho b|nh sit xuit huylt. Chiing tdi tim kiim cdc tiiugt ngft bao gim cdc tir d cd ba ngdn ngft chfnh thiic tgi Singapore: tiing Anh, Trung Quic Md Lai vd Tamil. Thugt ngft tim kiim cho cd Singapore vd Bangkok dd dugc phdn logi thdnh 3 logi:
danh phdp, diu hi|u/tri|u chiing vd diiu tri. Cdc thudt ngft tim kiim cho md hinh diy du"
dugc the hipn trong hinh I.
Singapore Bangkok
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Hinh 1: Biiu do biiu diln cdc budc lya chgn thudt ngft tim kiim
Trang tim kiim Google cung cip mOt logt cdc kit qud tim kiim cd liln quan. Tit cd cdc dft Upu tim kiim cd liln quan da dugc liy ra. Trang tim kiim Google bd qua chft hoa, nhung xir ly cdc loi chlnh td vd tiiir ty cua cdc tir khdc nhau (vf dy nhu "cdc tripu chiing ciim" vd "c6 tiilu chimg cdm") nhu Id nhfimg kit qud tim kiim rilng bipt. Tuy nhiin, dft lipu tim kiim cho cdc tradng hgp ndy Id nhd vd khdng bao gom trong tiiiir nghipm md Wnh.
Thdng tiiudng, cdng cy tim kiim Google si chi trd Igi dft li|u dugc tdp hgp theo tiidng, bdi vi mire dO tim kiim vdi vipc udc lugng hdng tuin Id khdng rd rdng. Ddi vdi nhung chi
S65-2011 TAP CHt PH6NGCH6NGBgNHS6TRiTVAcACBgNHK^ SINH TRUNG 25
tiiu ndy mdt spline khoi dugc sii dung phdn tdch cdc dft Ii|u dl ti-d Idi hdng tuin (sii dyng spline R; kit qua cd gid hi dm tii spline dugc tiiilt lap Id 0. Cdc dft lipu cfing dugc hoi quy vdi cdc tiiuat ngft ctmg m^t md hinh bdng cdch sft dyng dft lipu ting hgp hdng thdng, vd tiiu dugc kit qua tuong ty (xem dudi ddy). Quan trgng hon. Insight Google trd vl mgt miu khii lugng tim kiim tiiyc tl, dl sao chip chfnh xdc udc lugng ciia cdc dong biin md hinh Id khdng till.
D I chfnh xdc ddi vdi sy thay dii theo mtia vd gdy nhilu theo thdi gian, chiing tdi gOp Igi thdnh cdc thdng trong ndm (1 thay cho thdng M^t, 2 thay cho thdng Hai, .v.v...) vd ma si cho biit tuin tdi vd ndm ciia cdc dilm dft lipu hipn hdnh (dugc dua ra trong R Id so ngdy kl tu ngdy 1 tiidng 1 ndm 1970).
Dir lipu dich te
Dft lieu gidm sdt dich te dugc liy tir website cua Bp Y tl Singapore. Nhfing dft lipu dich te nay dugc thu thgp thudng xuyIn thdng qua cdc phdng khdm da khoa cua chfnh phu, cdc blnh vipn cdng, phdng thf nghipm 1dm sdng cfing nhu thdng qua cdc bdo cdo bdt bupc ve cdc bpnh trayin nhiem. Noi diiu tri vd phdng thf nghi|m xdc nhdn tradng hgp bpnh sot xuat huylt da dugc bdo cdo vl Bg Y tl tir ndm 1977 vd cdc dft lieu dugc tong hgp hdng tuan. Dft lieu ty Ip mdc mdi hdng thdng d Thdi Lan dugc thu tiigp tir website ciia Vdn phdng dich te Thdi Lan.
Google cung cip dft lipu tim kiim trin Intemet chi tir ndm 2004, nin chiing tdi chi xem xit dft Ulu ty Ip mdc blnh sot xuit huylt tir ndm 2004. Dft Upu ty 1? mdc mdi cho ca Singapore vd Bangkok dugc trinh bdy nhu Id cdc dudng mdu den trong hinh 2 .
Lua chon md hinh & Sv phu hgp
Chiing tdi xem xet hai gid tri cdc tradng hgp mdc sdt xuit huylt vd kit qua nhi phan: 1 Id trong thdi ky cd ty Ip mdc mdi cao vd 0 Id ngugc lai. Hdi quy tuyIn tinh da biin, hdi quy nhi thuc am vd hdi quy ddng biin dugc su dyng cho md hinh vdi ty 11 mac blnh sdt xuat huylt hang tuin bdng cdch sft dyng cdc thugt ngft tim kiim tren intemet. Su dyng hoi ciiu vd d\r dodn dh tim ra md hinh hoi quy tuyIn tfnh Id tii da hda cdc chi si thdng tin Akaike Hoi quy nhi thiic am phii hgp vdi cdc thilt lap diy dii cua cdc thugt ngft tim kiim d moi dia diem da dugc lya chgn trin hoi quy Poisson dh trdnh sy phan tdn cdc dft lieu tim kiim dugc. Cdc md hinh GBR dugc 1dm phii hgp vdi vipc su dyng cdc d GBM trong R .
Cdc md hinh de xuit sft dyng dft lipu tii 2005 - 2010 vd sft dyng dl dy dodn ty Ip mdc mdi vdo ndm 2011. Bao gom si Ulu ndm 2004 tft Singapore 1dm gidm do chfnh xdc trong vipc dy bdo cua md hinh. Do nhfing dy dodn thudng Id khdng giing nhau vd bao gom cd su chong chIo cua cac biin khi sft dyng hay khdng sft dyng si lieu cua nam 2004, chiing tdi da chpn dl toi uu hda dy dodn cua chting tdi vl ty 11 mdc trong nhfing ndm sau d6 bdng cdch bd dft Upu cda nam 2004 ra khdi cdc md hinh. Dl lya chpn gifta hoi quy tuyIn tinh, hoi quy nhi thuc am vd cac md hinh GBR, chiing tdi xdc dinh md hinh cd moi tuong quan Idn nhit cdc du dodn nam 2010 vd ty 1? mdc sau ndy. Md hinh ndy sau d6 da qua xdc nhgn dl ddnh gid hieu qua dy dodn. Chiing tdi sft dyng logi mdt gid tri vd mdt cfta so rdng cua dy dodn (doi vdi ca hdng tuin vd hdng ndm, hoi cftu vd dy dodn) cho dft Upu tim kiim tiieo ngdy gifta thdng 1 nam 2005 vd tiidng 12 nam 2010, vd dugc ddnh gid sai so trang binh binh phuong co sd (NRMSE) cua gid tri dy dodn cdc dft lieu liy tft ty 11 mdc mdi dugc quan sat.
26 TAP CHI P H 6 N G C H 6 N G B ^ N H SgT R§T vA c A C BgNH K'V' SINH TRUNG S6 5 - 2011
Singapore and Bangkok Dengue Incidence and Fitted Data With 2010 Prediction and Error
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Hinh 2: Sy tuong quan gifta ty Ip mdc b|nh sot xuit huylt quan sdt phti hgp vdi md hinh.
Ngodi ra vdi cdc md hinh dy dodn ty Ip mdc mdi, hii quy logic vd md hinh ho ttp Vector (SVM) da dugc sft dyng dl dy dodn thdi ky cd ty 1? mdc cao. Chiing tdi xay dyng cdc md hinh cho ba ngudng cd ty 1? mdc cao khdc nhau dugc xdc dinh Id nhftng nhdm tiiu 50,75 vd 90 cua so lugng cdc tradmg hgp mdc qua giai dogn 2005 2011. Md hinh thyc hipn dugc ddnh gid bdng cdch sft dyng dipn tich dudi AUC dl dua ra mgt dy dodn.
Tit cd cdc phdn tich tiling kl dugc tiiyc hipn trong R phiin bdn 2.12.2 (R Core Team).
3. KjfcT QUA
Cac mo hinh de Dur dodn so Ivgng ca mdc mdi.
Cdc budc sft dyng sft dyng md hinh AIC tit hon GBR vd md hinh nW thftc dm cho s6 lugng dy dodn cdc tradng hgp mdc mdi vd dugc lya chgn nhu Id toi uu d ca Singapore vk Bangkok. Cdc md hinh phii hgp nhit AIC cd nhfing thugt ngft tim kiim dy dodn dugc trinh bdy trong hinh 1. Bdng 1 cho tiiiy md hinh chin dodn so vdi cdc md hinh timg budc vd diy du cho Singapore vd Bangkok. Cdc moc thdi gian vd m^t logt cdc d l thi cho thiy ty 1? mdc
SOS 2011 TAPCH!PH6NGCHONG BgNHS6TRETvAcACBgNHKYSINHTRONG 27
blnh sot xuit huylt la binh thudng, cdc kit qua phii hgp vdi md hinh tii uu hda vd loi gifta dy dodn va ty 11 quan sat, dugc trinh bdy trong hinh 2.
Bang 1: Md hinh dy bdo ty 11 mdc.
Singapore Bangkok
Model Fit
Incidence Prediction
Terms r*
Con'elation AIC
Lag-0 Correlation Lag-4 Correlation
Full 20 0.948 0.931 2760.57 -
-
Stap-down
16 0.948 0.931 2751.559 0.666 0.785
Full 21 0.947 0.879 999.162 -
-
Stap-down
8 0.943 0.869 986.712 0.921 0.762
Dl ddnh gid hipu qua cua vile dy doan dua trin dft lieu ma khdng dugc sft dung dl phft hgp vdi md hinh, chiing tdi sft dung ky thuat xdc nhan qua gid tri dilm cat. Chiing tdi dy dodn ty 11 mdc trong nam 2010 d ca hai dia phuong bdng cdch sft dyng cdc md hinh phti hgp vdi dft Ulu tft 2005-2010. Sy tuong quan gifta nhfing dy doan sit xuit huylt trong nam 2010 vd ty 11 mdc mdi blnh sit xuit huylt dugc ghi nhdn cho ca Singapore vd Bangkok trinh bdy trong Bang 1.
Chiing tdi cung ddnh gid cdc dy dodn cho cdc ghi nhgn rilng Ie vd kit hgp ma cua cdc tap dft lieu dugc sft dyng phti hgp vdi md hinh. Nhfing kit qua ndy (dugc bdo cdo trong cong thdng tin ho trg SI) cho thiy mdt sy phti hgp cua md hinh timg budc mdt liln quan vdi vdi md hinh diy du. Ngodi ra, cdc sai sd dy dodn Id thip trong tradng hgp bd mdt ca blnh tuin mdt va tuin 52. Chung tdi ciing thiy hilu sy kim hilu qua cua md hinh nhi thuc am Uen quan den cac md hinh khdc.
Md hinh de dv doan thdi diem cd ty If mdc mdi cao
6 ca Singapore vd Bangkok, hoi quy logic vd cdc md hinh SVM phu hgp dl du dodn kit qua nhi phdn cd ty 1? tren hogc dudi ngudng. Hinh 3 tdm tdt cdc dy dodn cua md hinh SVM tai Singapore (tuong ta nhu do thi trinh bdy trong md hinh SVM d Bangkok dugc trinh bay trong cong ho trg thdng tin SI), va Bang 2 trinh bay AUC, do nhgy toi uu va do ddc hilu cho cdc md hinh logic va SVM cho moi mdt trong ba nhdm cdt bd. Chiing ta cd till dy doan tit tii vipc cdt trung binh vd cdt 75%.
28 TAP CHf P H 6 N G C H 6 N G BgNH S 6 T RJT vA CAc BgNH K^ SINH TRUNG s6 5 2011
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A U C - M 7 *
• S p « - 0664 V f i i - !
I t T 1 0 4 0 6 0 4 I D
1 SpccMklty
Hinh 3: Tdm tdt cdc dy dodn trong md hinh SVM d Singapore
Chiing tdi so sdnh hipu qua md hinh cfta chiing tdi vdi md hinh hoi qui ty dgng ngugc hudng bdng cdch chi sft dyng dyng dft lipu gidm sdt bpnh sit xuit huylt tft tuin cuii ciing (Singapore) hodc thdng (Bangkok) dl dy dodn lin quan sdt tiip theo. Tgi Singapore, md hinh ndy thyc hipn tit, mii tuong quan tuyIn tinh gifta nhflmg tradng hgp dy dodn vd mdc blnh dugc ghi nhgn Id 0,950. Tgi Bangkok, md hinh tiiyc hipn Id kim hon nhilu so vdi cdc md hinh su dyng cdc tiiuat ngft tim kiim vdi mgt mii tuong quan Id 0,766 {dh so sdnh, 8 md hinh tiiugt ngft tim kiim d ti-ln cd mgt moi tuong quan Id 0,943). Tuy nhiin, s\r chgm ti-e ti-ong vipc lap cdc bdo cdo ndy, ddc bipt Id tgi cdc dia dilm khdc cd till Id nhfing dft lipu ndy se khdng sii dyng dugc cho md hinh dy bdo ty dgng ty hii qui (autoregressive).
S65 2011 TAP CHI P H 6 N G C H 6 N G BgNH S6T RJT vA cAC BJNH KY SINH TRQNG 29
Bang 2. md hinh dur bdo ngudng chan dodn.
Cutoff P«rc*ntil«
No. cases SVM AUC SVM Sens.
SVM Spec.
Singapor*
50th 75th 105
0.925 0361 0.916
152 0.906 0.765 0.905
90th 277.8 0.979 1.000 0.864
Bangkok
50th 607 0.940 0.952 0.829
75th 770.75 0.960 1.000 0.839
90th 1134 0.988 1.000 0.986
4. T H A O LUAN
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Chiing tdi thay rdng cdc thugt ngft chuyin dyng tim kiem trin intemet cd liln quan chdt che vdi ty Ip mdc bpnh sot xuit huylt. Md hinh tit nhit cua chiing tdi cho dft lieu tft Singapore bao gom 16 thudt ngft cho thiy mdi tuong quan Id 0,931 vdi ty 1? mdc blnh sot xuit huylt dugc ghi nhgn vd ? = 0,948. Md hinh 8 tiiuat ngft cho Bangkok tiiyc hipn tit nhu nhau vdi moi tuong quan Id 0,869 vd r^ = 0,943. Mau dy dodn thip hon du kiln, nhung khdng cd nghia thdng kl. Du dodn cua chiing tdi ve khodng thdi gian cd ty II mac blnh sdt xuat huylt cao Id rit chinh xdc vdi do nhgy vd dg ddc hilu Id 0,861-1,00 vd 0,765-1,00 cho da ngudng trong moi dia dilm. Cfing vdi d6, nhiing ket qua ndy chiing minh khd ndng ton tgi ciia ddng dft lieu trong vipc ho trg gidm sdt blnh sdt xuat huylt.
Md hinh ciia chiing tdi thyc hipn tuomg ty vdi cdc md hinh dugc xay dyng trong cdc no lye khdc dl du dodn ty 11 mdc cdm bdng cdch sft dyng cdc thugt ngft tim kiim trin intemet.
Ginsberg vd cs. da tim thay hp sd tuong quan la 0,90 ddi vdi ty Ip mdc cum tgi My bang cdch sft dyng mdt md hinh bao gom 45 thudt ngft tim kiim. Polgreen vd cs. dua vdo mdt logt cdc md hinh dft lieu cdm tgi M>^ vd tit ca deu cd gid tri vdi r^ < 0,5. Trong vile dy dodn mau, cdc md hinh ciia chiing tdi dugc thyc hipn kim hon so vdi cdc md hinh ciia blnh ciim dugc gidi thilu bdi Ginsberg vd cs., vdi he si tuong quan 0,97 (so vdi 0,921 d Bangkok vd 0,785 tgi Singapore). Cin luu f rdng md hinh cfta chiing tdi dua ra cdc dy dodn cho cd nam bao gom cd miia mdc vdi ty 11 cao vd thip, trong khi cdc md hinh cua Ginsberg Igi chi dua ra dy dodn cho mfia mdc cdm. Do chinh xdc ciia nhfing dy dodn ciia chiing tdi cd thl Id do biiu hipn rd lam sdng cua blnh sdt xuit huylt ndng. Sy biin doi hdng ndm Idn hom cung cd thl cho phip chiing ta cd thl thay doi hdnh vi tim kiim theo mfta tft hdnh vi tim kiim sot xuit huylt cy thl.
Cdc thugt ngft tim kiim trong cdc md hinh bao gim cdc thugt ngft vl danh phdp, cdc tft ngft md ta nhfing diu hilu vd tripu chung cfing nhu vipc tim kiim phuong thuc dieu tii. Diiu tiiii vi Id trong sd 13 thugt ngft tim kiim tiii cd 11 tiiuat ngft dugc tiiiy Id cd nghia tiling ke trong md hinh cudi cfing cua chting tdi d Singapore bdng tiing Anh. Dieu ndy cho tiiiy rdng ngdn ngft diln hinh dugc sft dyng cho vipc tim kiim liln quan din sue khde tgi Singapore Id tiing Anh. Tgi Bangkok, chiing tdi cung phdt hien ra rdng ba trong bay thugt ngft tim kiim cd f nghia tiling kl la tiing Anh.
30 TAP CHI P H 6 N G C H 6 N G BgNH S 6 T R§T V A C A C BgNH KY SINH TRUNG s6 5 - 2011
Chiing tdi da thdng qua cdc md hinh dl xuit trong vipc sft dyng bd m^t quan sdt, bd m^t ndm quan sdt vd cdc ky thugt hodn thipn ngugc hudng vd ding hudng. Vipc thyc hipn md hinh Id khd nhit qudn qua cdc phuong phdp tiip cdn khdc nhau. Trong xdc nhdn cua chiing tdi tiiiy rdng, ty II mdc mdi cao trong mgt ndm cd dnh hudng Idn cho vi|c thyc hi|n cdc md hinh cua chiing tdi (qua cing tiidng tin hi trg SI). Chdng tdi hy vgng rdng trong nhftng ndm tdi vdi ty 1? mdc cao cd thl cdi thipn hom nfta kit qud cfta chiing tdi d tuomg lai.
Singapore cd m^t hp tiling gidm sdt b|nh sit xuit huylt rit phdt triln md cdc tradng hgp mdc mdi dugc bdo cdo cho cdc nhd hogch dinh chlnh sdch vd cdng chting ndi chung chi U-ong khodng mgt tuin. Trong m^t thilt Igp bdo cdo nhanh, d6 si Id diiu thdch thuc cho m6 hinh tim kiim thudt ngft trin internet cho kit qud nhanh chdng hon vd hipu qua tit hon so vdi mOt md hinh chi sft dyng cdc tradng hgp mdc dugc bdo cdo dh dy dodn cdc tradng hgp mdc trong tuomg lai. Dilm ndy da dugc chftng minh d nhiing noi khdc dh dy dodn hdnh vi cua ngudi tiiu dfing: thugt ngft tim kiim dy dodn dya trin nhfimg md hinh tiiyc hipn tit hon khi dugc sft dyng kit hgp vdi nhfimg bg dft lipu phong phii dOc lap. Nhu vgy, tgi Singapore, cdng cy ndy tit nhit cd till dugc sft dyng nhu Id mgt bo sung cho h? tiiong gidm sdt hipn cd. Tuy nhiin, trong cdc tiiilt lap khdc, vdi cdc hp thing gidm sdt kim phdt triln, hp tiling tiiuat ngft tim kiim dya trin intemet cd till mang Igi Igi Ich ddng kl trong vipc dua ra cdc dy dodn nhanh chdng. Tgi Thdi Lan, cd sy cham tre ddng ke trong viec bdo cdo cdc tradng hgp bi mac X
tft nhieu vfing miln cua dit nude. Md hinh cua chiing tdi cd thl hfiu ich cung cap cho cdc cai tiin trong cdc thilt lap vdi sy chdm tre ddng kl. Dieu dd cd thl tudng tugng rdng mgt sd viing dieh thilt lap blnh sdt xuat huylt luu hdnh d Nam vd Ddng Nam A cd the cd sft dyng intemet trade khi he thdng gidm sdt dugc phdt triln vd do dd mgt thudt ngft tim kiim trin internet dugc dya vdo md hinh cd the dgi diln cho gidm sdt thudng xuyIn trong cdc thilt lap ndy.
Sft dyng khi phuong phdp cfta chiing tdi khdi qudt dl thilt Igp cdc md hinh khdc can phai cin tigng. Mdc dft chftng tdi da chgn hai thilt Igp cd ti Ip sft dyng rit khdc nhau tren hitemet, cd hai quoc gia cd thu nhgp cao hom so vdi nhilu nude trong khu vyc. Tuy nhien, dieu dd Id hgp I^ trong vipc thfta nhgn rdng vipc sft dyng intemet ngdy cdng tdng trong tuong lai. Md hinh rilng II can phai dugc phdt triln cho cdc thilt Igp cy thl bdng cdch sft dyng dft Upu gidm sdt dia phuong vd cdc thugt ngft tim kiim. No lyc ndy cho thiy rdng phuong phdp tiip can ndy cd thl cd hua hpn trong vipc thilt Igp cdc md hinh khdc.
Cd mOt si hgn chi khdc trong nghien cftu cua chftng tdi. Thdi quen tim kiim trin intemet Id de bi tdc dgng bdi cdc ghi chip ciia cdc phuong tipn trayin thdng nhu da dugc thay ddi vdi nhfimg h? thing cua cdm. Ty 1? sft dyng intemet vd ty 1? tim kiim thdng tin y tl ti-ong vile thilt lap ndy cd thl dugc thay dii theo thdi gian vd do dd cdc thdng si cua chiing tdi cd thl cin phai thay dii theo thdi gian cho phft hgp vdi cdc tdc dgng cua nhfimg thay dii ndy.
Mdc dft hipu qua d ddy Id khdng bi dnh hudng, sy bftng phdt ti-ong tuong lai cfta cdc blnh khdc cd diu hilu lam sdng tiiong ty nhu chikungunya cd thl Id thdch thftc trong vile thuc hien md hinh ciia chftng tdi cho bpnh sit xuit huylt. Cuoi ciing, cdng cu tim kiim Google tia ve mdt mau dft lieu tim kiim thyc te vd sy hgn chi cdc thudt ngft tim kiim cd sdn dugc trd Igi rat it, thudng tap hgp nhftng thugt ngft ndy Id tgm thdi vd 1dm Diiu ndy hgn chi tipn ich ciia cdc thugt ngft cho cdc myc dich ciia dy bdo.
S6 5 - 2011 TAP CHI P H 6 N G C H 6 N G BgNH SOT RET vA CAC BJNH KY SINH TRUNG 31
Gidm sdt tray vin tim kiim dugc md rpng nhanh chdng sang nhilu Iinh vyc y tl cdng cdng, bao gom gidm sdt cdc bpnh khdng nhiem trfing vd dl dnh hudng din cdc ITnh vyc chfnh sdch. Cdng vipc ndy cho thiy tipn fch cua vile sft dyng gidm sdt tray vin tim kiim dl du bdo ty 11 mdc mdi mgt cdn bpnh trayin nhiem nhipt ddi. Thim vdo dd, vd quan trpng, chftng tdi da xay dyng md hinh dy bdo bdng cdch sft dyng dft lieu tray vin tim kiim mien phf ty do cd sdn tft Google vd dft lieu gidm sdt cdng khai cd sdn tft Singapore vd Bangkok.
Ngoai ra, chftng tdi da phdt triln cdc md hinh ndy bdng cdch sft dyng phin mem ma nguin md tft dy dn thing ke R. Phuong phdp tiip can cua chftng tdi cd thl de ddng thfch hgp vdi cdc cai dat khdc, noi md tdc ddng ban quyen khdng thl dugc thyc hipn. Cdch tiip can cd thl Id mdt cdng cy quan trgng trong nhieu vy dich sot xuit huylt trong vile ho trg y te cdng cpng dl phdng chdng sdt xuat huylt.
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Nguyin VSn DOng
Khoa Con triing, Vif n SR KST CTnT
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TS. Trinh Dinh Tirdmg Vifn S6t ret KST-CT TXT