Tgp chi Khoa hgc va Ky thugt -So 166(2-2015) - Hgc vi^n KTQS
Dir BAO CHAT LlTOfNG TO HOP TRANG BI TEN USX DAT DOI HAI REDUT-M BANG PHlTONG PHAP PHAN TICH HOI QUY
Dgng Dinh Todn
Bai bao trinh bay phuong phap d\f bdo tinh hinh chdt lugng cua t6 hc^ irang bi ten liia dit doi hai bang phan tich hoi quy dya tren cac dii lieu thSng kS \k chSt luang cua t6 hpp ten JLi'a h^ng nam, tir do xay dyng mo hinh h6i quy dk ti^n h^nh dir bao miic chdt lirong ciia timg loai to hop tSn lila trong tuong lai.
1. Dat van de
Td hgp trang bi ten lira dat ddi hai la mpt trong nhiing loai td hgp trang bj hien dai, ddi hdi dp chinh xac va kha nang lam viec tin cay eao dugc bien che trong luc lugng Hai quan nhan dan Viet Nam, nham gdp phan bao ve viing chic viing biln va dit lien cua Td qudc. Hien nay, eac to hgp ten lira nay cua quan doi ta gdm nhieu chung loai, the he khac nhau (Redut-M, Rubets-E, Bastion, Acuta va Extra). Mdt sd loai da tdn tai qua nhieu nam (Redut-M, Rubets-E), mpt so loai mdi dugc dau tu, mua sam (Bastion, Acura va Extra), do vay chat lugng khdng ddng deu. Trong qua trinh sir dung, lugng du trii ky thuat va chat lugng eiia trang bj giam dan theo thdi gian, cac bp phan, chi tiet chiu ma sat, va dap, nhiet dp, an mdn dien hda... din den tuoi thp giam dan va hu hdng. Viee nghien eiiu du bao tinh hinh chat lugng trang bi ten lua dat ddi hdi cho phep nam bat dugc quy luat thay ddi chat lugng trang bj theo thdi gian, lam co sd eho viee quy hoach sir dung trang bj va de xuat cac giai phap, bien phap khai thac trang bj mpt each hifu qua, tiet kiem va Mu dai.
2. Cff SO" ly thuyet
Phuang phap phan tieh hdi quy la phuong phap tim quan he phu thugc cua mpt bien (bien phu thupc vao mot hoac nhilu bien khac), dugc gpi la bien doe lap nham mue dich ude lugng hoac tien doan gia tri ky vpng cua bien phu thupc khi biet trudc gia trj cua bien dgc lap. Can cir vao mdi quan he giiia bien phu thugc vdi mpt hay nhieu bien dpc lap din den hinh thanh eae phuong phap phan tich hdi quy do la hdi quy dan bien va hdi quy da biln. Dudi day se tap trung nghien ciiu iing dung phuong phap hdi quy don tuyen tinh de phSn tieh, du bao. Trong dd, biln phu thudc la chat lugng eiia td hgp trang bj ten lira dit ddi hai Redut-M va biln doe lap la thdi gian (nam).
Hpc vien KTQS.
Journal of Science and Technology.-N. 166(2-2015) - Military University of Science and Technology
a) Md hinh hoi quy dcm bien [1]
Phuang trinh hdi quy dan bien ed dang tdng quat;
Y,=a + bX,+e, (1) trong do, X,Y,- gia trj cua biSn ddc lap vd bien phu thugc tai quan sat thii i; a- tung dd
gdc hay nut chan (intercept); 6 - dp ddc hay he sd gdc (slope); e, - thanh phan ngau nhien hay yeu td nhieu.
Tren thuc te, md hinh phuang trinh hoi quy tdng quat thudng dugc udc lugng thdng qua mau ngau nhien. Khi do, ta ed phuang trinh hdi quy miu ed dang [1];
Y,=a + bX, (2) trong do, i^- gia tri ude lugng cho gia trj cua bien Y d quan sat thii i;a - tung dp gdc
(niit cb^n); 6 - he sd hdi quy.
Nhu vay, de xay dung mo hinh hdi quy can phai tinh toan xae djnh cac he sd a, b cua phuang trinh hdi quy. Viec tinh toan nay dugc thuc hien bang each sii dung phuang phap binh phuong nhd nhat theo eac cdng thiic dugc trinh bay trong [1].
b) Danh gid suphu hop cua mo hinh
De dam bao sir phu hgp khi xay dung md hinh hdi quy, mgt trong nhihig ngi dung quan trpng do la do ludng, danh gia sir phii hgp cua mo hinh so vdi thuc te. Viee do ludng, danh gia nay duge thuc hien thdng qua tinh toan do ludng h6 sd xae djnh dS danh gia miic dp phit hgp cua md hinh hoi quy [3] va he sd thing ke F dl danh gia raiic y nghia cua toan bg md hinh [2],
- Danh gid mirc do phu hgp cua mo hinh hoi quy
Danh gia miic do phii hgp cua md hinh hdi quy dugc thuc hien thdng qua viec tinh toan do ludng su biln thien bing h? sd xae dinh (ky hieu R^) [3].
^^^SSR SST (3)
trong do, SST - t6ng biln thien cua bifa phu thuoc va duac tinh bSng cong thiic:
SST = f^(Y,-Yf (4) SSR - tong bijn thien cua h5i quy va duoc tinh bSng cong thitc:
SSR = ±(Y,-Yf (5^
174
Tgp chi Khoa hgc va Ky ihudt -So 166(2-2015) - Hgc vien KTQS
He so xac dinh la he sd dugc sir dung de danh gia mdi lien he tuyIn tinh giila biln phu thupc Y, vdi bien dpc I^p X^ trong md hinh. Gia trj ciia he sd xae dinh cho bilt bao nhieu phan tram su bien thien cua bien phu thupc cd thi dugc giai thich bdi cae biln ddc lap CO trong md hinh.
Cd the thay, gia tri ciia R- thda man 0<R~ <\
+ Nlu ^^ = 1 cd nghia la md hinh hdi quy giai thich 100% su biln thien cua Y + Nlu ^^ ^ 0, CO nghTa la md hinh khdng giai thich su biln thien nao cua Y - Kiem dinh gid thiet ve y nghia todn dien cua mo hinh hdi quy
De kiem dinh gia thiet ve y nghia toan dien eua md hinh hdi quy, ngudi ta sii dung he s6 thing ke F [2] dugc xae dinh nhu sau:
SSR
SSE (6)
n~k-}
trong dd, n la sd lugng mau va k la sd bien ddc lap.
Sau khi xac djnh duge gia trj F, ta tien hanh kilm djnh gia thilt tren theo quy tac: Neu F > F^(k,n-k-l,a), ed it nhat mdt trong cae bien dgc lap dang nghien cuu CO anh hudng len bien phu thupc. Trong dd, F^(k,n-k-\,a) la gia tri F gidi ban tuong ling vdi miic y nghta a (khi a = 0,05, tiic la do tin cay kiem djnh 95%), bac tu do d tir sd la k va bac tu do d mau sd la H - A: - 1 , gia tri F gidi han dugc xac dinh bang each tra bang phan phoi Fisher [3].
- Kiem dinh y nghia cua he so hoi quy
D^ kiem djnh y nghia eiia he sd hdi quy vdi dp tin cay 95%, co the dung kiem dinh t vdi gia thuyet dat ra H^: b = 0. Gia tri / tinh toan se duge so sanh vdi gia trj / gidi ban tra tir bang phan phdi Student vdi (n-k~l) bac tu do va miic y nghia a/2 = 0,05 / 2 = 0,25. Gia h:i / tinh toan duge xae dinh bing, cdng thiic [2]:
' = - (V)
S^
trong do, ^ - he sd dp ddc trong md hinh hdi quy mau; s^ - sai sd chuan ude lugng ciia he sd dg ddc eua biln dpc lap.
Quy tac kiem dinh /:
Neu / > '{„_.t,|.;,/2)" B^c bd gia thuylt Hg va cd the ket luan dugc vdi dp tin cay 95%, he sd hdi quy tdng thi khac khdng;
Journal ofSci e and Technology.-N. 166(2-2015) - Military University of Science and Technology
Neu t < /'(„_i_i ^,2) '• Chap nhan gia thi€t //(,.
Do vay, du bao bang md hinh hoi quy can phai xac dinh cae sai sd chuan khi du bao gia tn trung binh eiing khoang tin cay cho gia tri du bao do [2].
3. Ung dung phuong phap phan tich hoi quy d u bao chat luong cua to hffp trang bj ten lu-a dat doi hai Redut-M
Trang bi ten lira dat ddi hai la loai vii khi trang bi ky thuat hien d^i va quy hiem eua quan dpi ta hien nay, dugc bien che d cac Lii doan Ten lua bd - Quan chung Hai quan, day ia cac don vj tac chiln co ban, dugc td chiie, bien che trang bj ddng bg theo timg loai td hgp ten liia, bao gdm: Redut-M; Rubest-E; Bastion; Acura va Extra. Trong dd, td hgp ten lira Bastion, td hgp ten liia Acura va Extra mdi duge trang bi, thdi gian khai thac chua dai, nen sd lieu thing ke khdng nhieu, nlu su dung dl phan tich hdi quy thi kit qua dua ra cd dp chinh xae khdng eao. Vi vay, pham vi bai bao tap trung nghien cuu phan tieh tinh hinh chit lugng ddi vdi td hgp ten lua Redut-M.
a) Thu thap, xit ly dir lieu thong ke
Theo quy dinh, chit lugng cua mdi trang bj dugc phan thanh 5 cip (tir cip 1 din cip 5), trang bi cip 1 la trang bj cd chit lugng tdt nhit, trang bj cip 5 la trang bi cd chit lugng kem nhit (hu hdng, khdng con kha nang phuc hdi...). Nhu vay, gia trj chit lugng cua trang b; cang Idn thi chat lugng cua trang bj cang giam.
Viec thu thap du lieu vl chit lugng td hgp ten lua Redut-M dugc tdng hgp tir ngudn du lieu Tdng kiem ke 1/7 hang nam. Dii lieu ve phan cap chat lugng dugc thu thap tir 2006 den 2013, bao gom cap chat lugng cu the cua timg trang bi trong td hgp ten lira Redut-M theo timg nam.
Tren ea sd dii lieu ve cap chat lugng eua tirng trang bj cua td hgp ten Ida Redut~M theo titng nam (tir 2006 den 2013), ket qua tinh toan xac djnh chat lugng cua td hgp ten lira Redut-M theo timg nam nhu sau:
Bdng 1. Chdt hrgng cua to hgp ten lira Redut-M theo timg ndm (Ngudn: Tdng kiem ke 1/7 hdng ndm - TCKT) Nam
2006 2007 2008 2009 2010 2011 2012 2013
Cliat lirgng ciia t6 hgp ten lua Redut-M 2.185
2.202 2.224 2.246 2.261 2.274 2.302 2.330 176
Tgp chi Khoa hgc vd Ky thudt-Sd 166(2-2015) - Hgc vien KTQS
b) Xay dicng mo hinh hdi quy
Md hinh hdi quy dugc nghien ciiu la md hinh hdi quy don tuySn tinh, trong do bien ddc lap chinh la yeu td thdi gian T, bien phu thupc la chat lugng cua td hgp ten lua Redut-M bien thien theo thdi gian T, dugc ky hieu la Y. Khi dd, md hinh hdi quy cd dang nhu sau:
Y = a + b.T (8) trong dd, Y- chit lugng cua td hgp ten Ida Redut-M (1 < T < 5); a- tung dp gdc hay nut
chan; A - he sd hoi quy; T- yeu td thdi gian tinh theo nam (biln ddc lap), gia trj T duge xae dinh kl tir khi td hgp ten lira Redut-M bit diu dua vao khai thac.
Tuy nhiSn, d6 dam bao dii lieu dua vao phan tieh hdi quy khdng bj xao trpn va bien dgng dot nggt, ta su dung mgt sd gia thilt sau:
- Sd lugng va chung loai trang bi trong cua td hgp t6n lira Redut-M khong thay ddi trong toan bp qua trinh tir khi dua vao khai thac din khi loai khdi biln chi;
- Mdi trang bi trong td hgp ten lua Redut-M deu cd vai trd nhu nhau trong viec dap ling cac ySu eau ve tinh nang k5' chien thuat cua tl hgp ten liia;
- Trong khoang thdi gian quan sat thu thap dii lieu thdng ke, cd tinh din cac boat ddng siia chua, nhung khdng tinh den trudng hgp tang ban cho toan bp td hgp ten liia.
TrSn CO sd md hinh tdng quat (2), viec xay dung md hinh hdi quy vl chit lugng dugc thuc hien bang each tinh toan xac djnh gia trj cac h^ sd a, b. Sau khi tinh toan, thay cac gia tri a, b vao md hinh (8), tu do se xac djnh dugc md hinh hdi quy cu thi bilu dien mdi quan he tuyen tinh giiia chat lugng Y eua td hgp ten lira Redut-M theo thdi gian T (nam).
Nhim bao dam cho viec tinh toan dugc thuan tien, nhanh chdng va chinh xac, bai bao sii dung phan mem phan tich thdng ke SPSS de tien hanh tinh toan. Sau khi nhap gia trj cua cac bien dgc lap T, bien phu thudc Y vao phin mem va tien hanh chay hdi quy, phan mSm cho ra bang ket qua phan tich sau:
Bdng 2. Ket qud tinh todn he so hoi quy cug md hinh hdi quy ve chdt lugng td hgp ten lira Redut-M
1 (Constant)
T
He s6 chua chuan hoa
B -37.937
0.020 Do lech
chuan 1.550 0.001
He s6 chuan hoa
Beta
0.996 t
-24.470 25.923
Mucy nghTa (sig.) 0.000 0.000
Thdng ke cgng tuyen Chip nhan -41.731
0.018 VIF -34.143
0.022
ThSng ke cpng tuyen Chap nhan 1.000
VIF
1.000
Journal of Science and Technology.-N. 166(2-2015) - Military University of Science and Technology
Tir bang 2, can eii vao cot gia tri B se xae djnh dugc cac gia tri a, b cua md hinh.
C u t h l : a = - 3 7 , 9 3 7 , 6 = 0,020.
Nhu vay, md hinh hdi quy ve chat lugng td hgp ten liia Redut-M cd dang nhu sau:
y = - 3 7 , 9 3 7 + 0,020.r (9) c) Danh gid suphu hgp cua md hinh
- Danh gia miic dp phii hgp eiia md hinh hdi quy
Sir dung phin m I m phan tich thdng ke IBM SPSS d l tinh toan se cho ra bang ket qua sau:
Bdng 3. Tdm tdt kit qud phdn tich md hinh hoi quy vi chdt lugng to hgp ten lica Redut-M
Mo hinh 1
R
0.996"
^-
0.991
^'adj
0.990
Sai so chuan cua uoc
lugng 0.005
Th6ng kS thay doi R' thay f thay
d6i 1 d6i 0.991 1672.000
dfl 1
df2 6
Mircy nghTa F thay d6i 0.000
Durbin- Watson 1.460 Can cii vao bang ket qua tdm tat cua md hinh hdi quy (Bang 3) cho thay: Gid trj R' hieu chinh (ky hieu la Rl.) bang 0,990 (if^,,^>0,6), dieu dd chiing td rang bidn dpc lap T giai thich dugc 99,0% sir bien thien eua bien phii thupc (chat lugng ciia td hgp ten lua Redut-M). Vdi gia trj Rl^^ nay, cd the ket luan md hinh hdi quy du gia trj tin cay va phii hgp vdi eac dii Heu quan sat.
- Danh gia y nghia cua toan bp md hinh
Viec danh gia y nghTa ciia toan bp md hinh dugc thuc hien b i n g k i l m dinh dp phii hgp cua md hinh hdi quy tdng the (kiem dinh F) va kiem dinh v l y nghTa ciia he sd hdi quy (kiem djnh /).
+ Kiem djnh F : Can cii vao ket qua phan tich hdi quy bang phan m I m SPSS, ta CO bang ket qua phan tich phuang sai (ANOVA) sau:
Bdng 4. Ket qud phdn tich phuang sai (ANOVA) cda md hinh hdi quy ve chdt lugng cua td hgp ten lica Redut-M
Mo hinh
1 Hoi quy
Du Tong
T6ng binh phuong 0.017 0.000 0.017
df 1 6 7
Giatri trung binh binh phuang
0.017 0.000
F 672.000
Miicy nghTa 0.000'
178
Tap chi Khoa hgc va Ky thudt.-Sd 166(2-2015) - Hgc vien KTQS
Tir bang 4 cho thiy, gia tri cua he so thang ke F = 672,000. Trong khi do, gia tri he s6 thdng ke F^(k,n-k-\,a) vcti n = 8, *: = !, n - t - 1 = 8-1-1 = 6, a = 0,5, tia bang phan ph6i Fisher ta dugc F^i.k,n-k-\.a) = 5.99. Nhu vay, F > F^{k,n-k-\,a), gia thiSt Hg (R' cua tdng thi bSng 0) bi bac bo, mo hinh hoi quy dugc xay dung phii hgp vol mo hinh^tSng the.
+ KiSm dinh / : Nham kigm dinh y nghia cua he s6 hoi quy b de bao dam bien dgc lap thuc sir co anh huong den bi8n phu thugc.
Can cir vao bang ket qua tinh toan he so hoi quy cua mo hinh hoi quy chat lugng t6 hgp tSn lira Redut-M (Bang 2), 6 cot gia tri t tuong ifng vai bien dgc lap T, xac dinh dugc ( = 25,923 va miic y nghia Sig. = 0,000.
Vgi gia thuylt //g: 6 = 0, do tin cay 95% thi mirc y nghia Sig. cua bien dgc lap r < 0,05 . Nhu vay, gia thidt H„ bi bac bo.
Mat khac, gia tri tai han r,„_j_i„,,, vol n = 8, k = \, a:/2 = 0,05/2 = 0,25, sau khi tra bang phan ph6i Student xac dinh dugc r,„_j_i,„,2| =2,4469. So sanh gia tri / tuong ung vai biln d6c lap T vai gia tri toi han (,„_j_i „;,) cho thiy t > f„,_n „/2i • Bieu do chung to rang, biln dgc lap T cua mo hinh nghien ciru co anh huang den bien phu thugc Y.
Nhu vay, sau khi tiln hanh danh gia su phii hgp cua mg hinh hIi quy ve chat lugng t6 hgp ten lira Redut-M, co thi kit luan cac mo hinh h6i quy dugc xay dung la phu hgp, biln dgc lap co thi giai thich tit cho biln phu thugc trong mo hinh va mo hinh nay co thi su dung dl du b4o vl chSt lugng cua tl hgp ten lira Redut-M.
d) Sir dung mo hinh hdi quy du bdo chdt luang cita to hop ten Ilia Redut-M Tren ca sa mo hinh hoi quy vl chit lugng t6 hgp ten lira Redut-M, cho phep xac dinh gia tri du bag uoc lugng vl chit lugng, khoang tin cay cho cac gia tri du bao trung binh va khoang tin cay cho du bao mgt gia tri rieng le tai thai diem 7; (nam) nao do can du bao.
Vi du cin du bao vl chit lugng tl hgp ten lira Redut-M tai thoi diem r„ = 2030.
Klii do, gia tri du bag uac lugng va cac khoang tin cay dugc xac dinh nhu sau:
- Gia tri du bao uac lugng vl chit lugng tl hgp ten lua Redut-M tai thai dilm T; = 2030, ky hieu Y;
Journal of Science and Technology.-N. 166(2-2015) - Military University of Science and Technolo^
Thay ?; = 2030 vao md hinli hdi quy (9), ta cd: i; =-37,937 + 0,020.2030 = 2,663 - Khoang tin cay 95% cho cac gia trj du bao trung binh tai thdi diem TJ, = 2030.
Tir cdng thiie xae dinh khoang tin cay eho cac gia tri du bao trung binh [2], tien hanh tra bang gia trj phan phdi ?,„_2 ^^ii) va tinh toan sai sd chuan khi du bao gia trj trung binh tai T^ = 2030.
Gia trj /,„_2«/2) vdi w = 8, H - 2 ^ 6 (bactudo), a / 2 = 0,05/2 = 0,025, tra bang phan phdi Student xae dinh dugc Z,,,.,,,/,) = 2,4469.
Ta cd thi tinh toan dugc cac gia trj eua sai sd chuan S va sai sd chuan khi du bao gia trj trung binh 5,^ nhu sau:
-i^'f
8-2 = 0,00204c =5 I I . 5^°-^)' =0,002Q4.|i.P°^»:'°°^-^^^0,00649
Z(^,-xf
42,000trong do, cac gia trj Y^,Y, dugc xac dinh tir bang 5.
Bdng 5. Ti'nh loan long biin thien cua bien phu thuQC vd bien doc lap T
2006 2007 2008 2009 2010 2011 2012 2013
z
Y 2,185 2,202 2,224 2,246 2,261 2,274 2,302 2,330
Y 2,183 2,203 2,223 2,243 2,263 2,283 2,303 2,323
(Y,-tf
0,000004 0,000001 0,000001 0,000009 0,000004 0,000081 0,000001 0,000049 0,000150
T
2009,5
(T,-Tf
12,250 . 6,250 2,250 0,250 0,250 2,250 6,250 12,250 42,000 Thay cac gia tri f(„_2,„/2) va S^g vao c5ng thiic (xem [2, dong 17, tr. 187]), xac djnh dugc khoang tin cay 95% cho cac gia tri du bao trung binh can tim la:
180
Tap chi Khoa hoc vii Ky ihuai. -Sd 166(2-2015) - Hoc vien KTQS
(2,663-2,4469*0,00649; 2,663-1-2,4469*0,00649) = (2,647; 2,679) - Khoang tin cay 95% cho cac gia tri du bao rieng le tai thai diem 7; = 2030 : Tir bang 5, cho phep xac dinh dugc gia tri sai so cliuan cua dir bao gia tri rieng le S,ff theo cong thirc [3] nhu sau:
S,^, .S | l . l . J ^ . z Z ) L = o,00204 L l + ^ ? M Z ^ ^ ^ ^ = 0,00681 n f(^x-Xy- V 8 42,000
Thay cac gia trj /,„_, ^^,, va 5,^, vao cdng thirc [21), xac djnh duge khoang tin cay 95% cho cae gia tri du bao rieng le can tim la:
(2.663-2,4469*0,00681; 2,663+2,4469*0,00681) = (2,646; 2,680)
Tir ket qua du bao tai thdi diem T^ = 2030 cho thay, chat lugng cua td hgp ten lua Redut-M y^ = 2,663 vdi klioang tin cay eho cac gia trj du bao trung binh la (2,647; 2,679) va khoang tin cay eho cac gia tri du bao rieng le la (2,646; 2,680), eac gia trj nay deu nho hon 3. Trong khi do, theo quy dinh phan cap chat lugng, eac trang hi ed cap chat lugng < 3 la nhiing trang bj cd tinh trang ky thuat tdt, kha nang boat ddng binh thudng.
Nhu vay, vdi ket qua du bao nay ta cd the di den ket luan: Den nam 2030 td hgp ten Ida Redut-M vin bao dam tinh trang ky thuat tot, tiep tue dugc khai thac, sir dung binh thudng. dii kha nang thuc hien nhiem vu san sang chien dau va chien dau.
4. Ket luan
Tren co sd phuang phap phan tieh hdi quy. bai bao da xay dung md hinh hdi quy bieu dien mdi quan he giua miie chat lugng ciia to hgp ten lira dat doi hai Redut-M theo thdi gian (nam), ddng thdi danh gia mue do phii hgp ciia mo hinh. Tii' md hinh hdi quy da xay dung, cho phep tien hanh du bao chat lugng cua td hgp ten lira tai thdi diem bat ky trong tuong lai va khoang tin cay cho eac gia trj du bao do. Day chinh la ca sd quan trpng trong qua trinh lap kl hoach kliai thac, quy hoach sir dung va tang ban trang bj. Ddng thdi, ket qua du bao con la co sd de xuat cac giai phap phu hgp. hieu qua trong td chue khai thac trang bi, ban ehl tdi da sir xudng cap chat lugng va luoi thg, duy tri kha nang lam viec va dp tin cay eua trang bj ten lira dit ddi hai, bao dam eho trang bi ten lira dat doi hai ludn dap iing yeu ciu thuc hien nhiem vu sin sang chien dau va chien dau.
181
Journal of Science and Technology.-N 166(2-2015) - Military University of Science and Technology _
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Nxb Thing ke. Ha Npi, 2008.
3. Hoang Trpng, Chu Nguyen Mong Ngpc. Thdng ke dng dung trong kinh te - xa hoi.
Nxb Lao dpng Xa hpi, TP. H6 Chi Minh, 2011.
Ngay nhgn bdi: 20 thdng 8 nam 2014 Ngay nhdn bdn si^a lan cuoi: 11 thdng 11 nam 2014
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