O^ TAI NCKH CAP OHQGHN Boneck [5] cung nhu nhung ngudi khac dinh nghia m6t DSS nhu la mOi he th6'ng dua tren may tinh bao g6m ba thanh phan tuong tac: 1 MOt he ng6n ngu-m6t co che' di tr
Trang 1DAI HOC QUOC GIA HA NOI
TRLTdNG DAI HOC KHOA HOC TO NHIEN
Trang 2DAI HOC QUOC GIA HA NOI TRirdNG DAI HOC KHOA HOC TU NHIEN
Chu tri de tai: PGS.TS Nguyen Van Vy
Tham gia: CVCC Nguyin Hiru Nguyen
TS Cao Ngoc Chau
CN Nguyen Ha Nam
Trang 3BAO CAO TINH HINH TUlJC HIEN DE TAI
NGHIEN Ctru KHOA HOC CAP DHQG
B Chu tri de tai: PSG.TS Nguyin Van Vy
C Can bo phot hap: CVCC Nguy6n Huu Nguyen
TS Cao Ngoc Chau
CN Nguyen Ha Nam
Z) Muc tieu vd not dung de tai:
L Ly thuyet: Thir nghiem phan tich va thiet ke mot he Ira giiip quyet dinh cho vice lap
ke hoach chien luac GTVT
3 Noi dung 6i tai
- Xac dinh cac bai toan dat ra trong boat ciia dong lap ke hoach chien luac phal trien Giao thong van tai va tim cac mo hinh tbich hop cho no
- Tien hanh thu nghiem va khai thac cac pham mem cong cu de giai cac mo hinh cac bai toan dir bao va mo hinh cac bai toan toi uu
- Thict ke buac dau he Ira giiip quyet dinh cho cac bai toan dat ra va tien hanh lap trinh thii nghiem he thong tra giiip c6 su dung cac phan mem cong cu de tra giiip mot so trong cac bai loan lap ke hoach chien luac duac nghien ciiu
E Ket qua
Trang 4Tir do da thiet ke duac nhung phin ca ban cua mot he trg giiip quyet dinh
cho heat d6ng nay
El.Ket qua thv[ nghiem
• Tife'n hanh thu nghiem va khai thac su dung bai he phan mem c6ng cu ve du
bao va cac bai toan toi iru phu vu cho viec cau tnic he trg giiip: He Eview va
he Lingo
• L$p chuang trinh thu nghiem tren may h6 trg cho viec giai quyet ba bai toan
quan trong trong s6' cac bai toan du bao va lap ke hoach chien luge phat trien
giao thong van tai:
- Bai toan du bao ngoai suy theo ham hoi quy
- Bai toan quy hoach tuyen tinh cho viec phan b6 lu6ng hang
- Bai toan danh gia y kie'n chuyen gia Dae biet doi vai lap bai toan lap ke hoach phan b6 lu6ng hang da thir nghiem
vai bai toan c6 quy m6 tren 600 bien va han 400 rang bugc va da dugc tu dong hoa
toan bg qua trinh giai quyet bai toan tu khau cap nhat du lieu den khau dua ra ket
qua theo yeu cau sir dung
E3 Cac ket qua khdc
• Dang mot bai bao trong tap chi Giao thong van tai (so 7/2001)
• Huang din va da bao ve thanh cong :
- M6t luan van thac sy va
- Mot khoa luan tot nghiep dai hgc
Gl Tinh hinh su: dung kinh phi de tai:
T6ng kinh phi de tai da chi la: 15.000.000 d6ng
trong do + Thue chuyen mon: 9.000.000d6ng
+ Cac chi khac: 4.000.000 d6ng + Viet va hoan thien bao cao, t6 chuc nghiem thu: 2.000.000 d6ng
XAC NHAN CUA KHOA
PHOCHUNHIEMKHOA
Ha noi, Ngay 30 thang 11 nam 2002
CHU TRI DE TAI
POSTS Nsuven van Vv
Trang 5REPORT ON THE EXECUTION SITUATIONS OF NATIONAL INSTITUTE-LEVEL SCIENTIFIC RESEARCH
SUBJECT
A Subject title
Decision Support System for Strategic Transport Planning
Subject code : QT-99-03
B Subject^s leader : Prof Dr Nguyen Van Vy
C Researcher-Participants: High Degree Expert Nguyen Huu Nguyen
Dr Cao Ngoc Chau
BS Nguyen Ha Nam
D Subject *s Aims and Contents
L In Theoretical research: Essay in the analysis and design of a support system for
making decision in strategic planning of the transport industry
2 In Experimental research activities:
• Research on the exploitation of some software utilities systems in order to seize their capabilities and their methods for the solution of some models
• Performance of programming support program-utilities for the solution of some typical problems in the complex series of which being identified in various strategic planning activities
3 Subject's contents :
• Identification of problems generated in the activities of strategic planning for the Development of Transport Industry and recognition of more appropriated models among them
• Performance of testing and exploitation of utilities softwares for solving models of forecast problems and the ones of optimization problems
• Preliminary design of support system for making decisions on these recognized problems and performance of the programmation for testing the support system with the aid of utilities softwares in the solution of some among the studied problems in the strategic planning activities
E Obtained Results
El On scientific research results: Preliminary analysis for identifying various problems
in strategic transport planning activities and recognizing appropriated models for them
Trang 6E2 On experimental results :
• Performance of testing and exploiting two utilities softwares, the one in
forecast domain: the EVBEW software, the other in optimization domain: the
LINGO software
• Performance of programming and testing of programs which aid the
exploitation of these software systems for solving three important problems
among those of forecasting and planning in the transport strategic
- Problem on assessing the expert suggestions
In particular, for the Goods traffic aloocation planning problem, the one with
600 variables and more than 400 constraints has been tested and the complete
process of its solution from the steps of input data, allocation of variables,
elaboration of model basing on the regulations of the software for computer solving,
run the utilitues software, reception and analysis of computed resuls written in form
of various reports, has been automated
E3 Other results
• An article (on this subject results) has been published in the Transport
Journal (No.7/2000)
• Scientific guide and successful pass for
- a Master of Sciences thesis and
- an University graduation of a class
G Spended expenses situation
Total expenses at subject's disposal ;
Having been spended : -i- for specialists hire
-h for other expenses
VND 15,000,000
VND 9,000.000 VND 4.000.000 -h for report completion and acceptance VND 2.000.000
Trang 7MUC LUC
• •
Ldi noi dau
Chuang I TONG QUAN VE HE TRO GIUP QUYET DINE
1.1 Dinh nghTa he trg giiip quyet dinh 1
1.2 Cac thanh phan cua DSS [3] 2
1.3 Cac thong con trong DSS [3] 4
1.3.1 He thong con quan tri dulieu 4
a Co so du lieu 4
b He quan tri CSDL 5
c Phuong tien truy van 7
d Tir di^n du lieu 7 1.3.2 He thong con quan tri mo hinh 8
a Co so mo hinh 8
b He quan tri co so mo hinh 10
c Tirdien mo hinh 10
d Thuc hien, tich hop mo hinh va lenh 11
1.3.3 He thong con tri thiirc 11
1.3.4 He con giao dien hoi thoai ngudi sir dung 11
1.3.5 Nguoi sudung 13 1.3.6 Phan mem va phan ciimg cua DSS 14
Chuang II NHUNG VAN DE CUA KE HOACH CHIEN LUDC G L \ 0
THONG VAN TAI VA CAC MO HINH CUA NO
2.1 Bai toan dat ra cho ke hoach chien luge giao thong van tai 16
2.2 Nhung van de phuong phap luan cua dir bao van tai 17
2.2.1 Cac noi dung dir bao ve nhu cau van tai 17
a Cac dir bao ve van tai hang hoa 18
b Cac dir bao ve nhu cau van tai hanh khach 20
2.2.2 Cac dieu kien, tien de cho cac dir bao 22
2.3 Cac mo hinh va phuong phap du bao van lai 24
2.3.1 Mo hinh ngoai suy 24
2.3.2 Mo hinh mo phong 25
2.3.3 Mo hinh tuong tir 27
2.3.4 Mo hinh bai toan quy hoach 27
Trang 82.3.5 Phuong phap chuyen gia va bai toan sdp hang 30
2.3.5.1 Phuong phap chuyen gia 30
2.3.5.2 Bai toan sSp hang y kien chuyen gia 31
2.3.6 Phuong phap he so dan hoi 32
2.3.7 Phuong phap dinh miic -he so 33
2.3.8 Cac phuong phap khac 34
2.4 So do tien hanh cac du bao ve van tai 35
2.4.1 So do chung du bao khoi lugng van tai hang hoa 35
2.4.2 So do chung du bao khoi luong van tai hanh khach 37
2.5 Phan tich, lua chon mo hinh du bao van tai hang hoa 43
2.5.1 Du bao khoi luong van tai hang hoa ca nu6c 43
2.5.1.1 Cac nhan to tac dong: 43
2.5.1.2 Lira chon cac mo hinh du bao 45
2.5.2 Du bao khoi luong van tai trong nu6c, ngoai nu6c 46
2.5.2.1 Cac nhan to tac dong 46
2.5.2.2 Lua chon phuong phap du bao 47
2.5.3 Du bao khoi lugng van tai tai cac vung, dia phuong 48
2.5.3.i Cac nhan to tac dong ^ 48
2.5.3.2 Lira chon phuong phap du bao 49
2.5.4 Du bao khoi luong van tai theo phuong thurc van tai 50
2.5.4.i Cac nhan to tac dong 50
2.5.4.2 Lua chon phuong phap du bao 51
2.6 Du bao khoi lugng van tai theo cac tuyen chinh 60
Chuang III PHAN TICH THIET KE HE THONG TRO GIUP
3.1 Tong hop cac mo hinh va phuong phap 61
3.1.1 He thong hoa cac mo hinh, phuong phap sirdiing 61
3.1.2 Sod6 tong quat cac mo hinh va phuong phap sir dung 63
3.2 Tien trinh giai quyet mot so bai toan chinh 65
3.2.1 Mo hinh ngoai suy 66 3.2.2 Mo hinh mo phong 68 3.2.3 Mo hinh tuong tu 69 3.2.4 Mo hinh bai loan quy hoach 71
3.2.5 Phuong phap chuyen gia 73
3.2.6 Cac phuong phap khac 74
3.3 Thiet ke mo hinh du lieu 74 3.3.1 T6ng quan ve cac loai diJ lieu 74
Trang 9a Cac du'li^u dung chung 74
b Cac du li6u cho phuong phap du bao cu th^ 74
3.3.2 Mo hinh dii lieu chinh 75
3.3.2.1 Dinh dang cac dulieu dung chung 75
3.3.2.2 Dinh dang cac d u lieu cho cac bai toan ngoai suy 77
3.3.2.3 Dinh dang cac du lieu cho cac bai toan quy hoach 77
3.3.2.3 Dinh dang cac du lieu cho cac bai toan chuyen gia 78
3.4 So do thiet ke' t6ng the' ciaa he thong 75
Chuang IV HE THONG CAC CHUDNG TRINH THlTNGHIEM
4.1 Thu nghiem phdn m e m EVIEW de du bao 82
4.1.1 Gi6i thieu ve ph^n m e m EVIEW 82
4.1.2 Sudung Eview tien hanh cac dubao 82
4.1.3 Kha nang tich hop EVIEW trong he trg giup 83
4.2 P h ^ m e m trg giup bai toan phan b6 luong hang 83
4.2.1 Bai toan phan b6 cac mat hang chinh 83
a Dieu kien bai toan: 83
b Dat bai toan 84
4.2.2 He thong chuong trinh thir nghiem 85
a Mo ta he th6ng 85
b Cach sudung 87
4.2.3 Ket qua tuih toan va nhan xet 88
a Ket qua tinh toan thii nghiem 88
b Mot so nhan xet 89
4.3 Phan m e m trg giup d u bao van tai hang hoa 9C
4.3.1 Gi6i thieu he thong [8] 90
4.3.2 He thong d u b a o khoi lugng van tai ca nu6c 90
4.4 Phan m e m trg giup quye't dinh v6i danh gia ciia chuyen gia 10^
4.4.1 Cac bai toan xu ly y kie'n chuyen gia 106
a Bai toan khong nhan 106
b Bai toan co nhan 106
4.4.2 He thong trg giup quyet dinh [9] 107
a Gidi thieu ve he thong 107
b Mo so ket qua 108
c Mg so giao dien ciia he trg giiip quyet dinh 109
Tai lieu tham khao 11^
Trang 10LOINOIOAU
Viec umg dung tin hoc hoa trong cac boat dong quan ly ngay cang phat tri^n manh me Trong so cac he thong thong tin dugc xay dung, he trg giiip quyet dinh co mot y nghia r^t quan trong trong viec nang cao ch^t lugng ciia cac quyet dinh quan ly Viec nghien ciiru d^ xay dung nhung he trg giup chung cho nhieu boat dong khac nhau doi hoi rat nhieu cong cua Them vao do, nhiing he nhu vay thucmg kho su dung hoac doi hoi nguoi su dimg phai co trinh dp cao hay phai co thcri gian dao tao du dai Vi ly do do, nhieu he trg giiip cho viec ra quyet dinh quan ly thucmg dugc xay dung cho mot linh vuc hay nhung boat dong cu the' De tai "He trg giup quyet dinh cho bai toan lap ke hoach chien luge giao thong van tai " dugc dat ra di theo hu6ng nay
V6i th5i gian va kinh phi co han, de tai m6i chi dijng lai 6 miirc thiet ke va tien hanh thu nghiem xay dung he thong 6 tren nhung phan co ban nha'l Con nhieu thanh phdn chua dugc xem xet Them vao do, nhung phan thu nghiem mac
du CO the su dung dugc, nhung chua tien dung D^ co the dua no vao sir dung c^n phai tie'p tuc hoan thien them nhieu nua Tuy nhien, qua viec nghien ciiru thu nghiem nay da giup cho nhung ngucri giang day va nghien ciiru ling diing nhieu kinh nghiem va tu Heu quy d^ phu vu cong tac giang day va trien khai limg dung
Noi dung bao cao cua de tai ngoai phan muc luc, ket luan, tai lieu tham khao va phii liic bao gom bon chuong:
Chuang I Tong quan ve he tra giup quyet dinh
Chuang II Cac van de cua ke hoach chien luac giao thong van tai va cdc
mo hinh cua no
Chuang III Phan tich thiet kehe thong ira giup
Chuang I\' He thong cdc chuang trinh thu ngliiem
Trang 11CHCfCfNG I
• • •
1.1 Dinh nghia he tra giiip quyet dinh
Vao dSu nhung nam 1970 Scott-Morton da dinh nghia cac he trg giiip
quyet dinh (Decision Support Systems - DSS) nhu la "cac he th6ng dua tren
tuong tac may tinh, no giup cac nha quan ly ra quye't dinh sir dung du lieu va
cac m6 hinh d^ giai quye't cac vSih di khOng co ca'u truc"[81 Sau do Keen va
Scott -Morton [4] b6 sung them la: Cac he th6'ng trg giiip quyet dinh ke't hop
cac ngu6n luc tri tue cua con ngu5i vdi nang luc ciia may tinh d^ hoan thien
chat lugng cua cac quye't dinh Nhu vay, cac he th6ng trg giiip dua tren may
tinh dua ra cac quye't dinh quan ly d^ giai quye't cac vSii d^ ca'u tnic khCng ro
rang Cac 6ng da khang dinh rang, d^ thanh c6ng, m6t he thC'ng nhu vay phai
la:
(1) Don gian
(2) Trangkien
(3) De di^u khi^n
(4) Co kha nang thich nghi
(5) Giai quye't trgn ven m6t vSih di va
(6) De dang trong giao tie'p
Ba dinh nghia khac ve DSS dugc Moore va Chang[6], Bonczek, Holsapple
va Whinston[l], Keen[5] dua ra Theo ho, DSS dugc dinh nghia nhu la:
(1) He th6'ng CO th^ mo rCng,
(2) Co kha nang h6 trg phan tich du lieu cu the va mo hinh hoa cac quyet
dinh
(3) De lap ke hoach cho tuong lai, va
(4) Dugc su dung bat quy tac vdi khoang thoi gian khong dugc ke hoach
truoc
Trang 12O^ TAI NCKH CAP OHQGHN
Boneck [5] cung nhu nhung ngudi khac dinh nghia m6t DSS nhu la mOi he th6'ng dua tren may tinh bao g6m ba thanh phan tuong tac:
(1) MOt he ng6n ngu-m6t co che' di truydn th6ng giua nguoi su dung va
cdc thanh j ^ ^ khac ciia DSS,
(2) M6t he tri thurc - kho chiia cac vgji d^ tri thiic theo linh vuc dugc nhiing trong DSS g6m ca du lieu va cac thu tuc, va
(3) M6l he xu ly vaan di lien ke't hai thanh ph£n tren, chiia m6t hoac nhi^u
kha nang xu ly cac v ^ de dugc yeu ciu de ra quye't dinh
Vi vay 6ng da dinh nghia DSS nhu la m6t san ph^m ciia qua trinh phat tri^n, trong do ngudi sir dung, ngudi xay dung DSS va chinh DSS co kha nang gay anh hudng t6i nhung ph^n khac, tao ra m6t su tie'n hoa cho he thO'ng va nhung khu6n miu cho viec sir dung ciia no
Theo cac quan di^m tren, m6t DSS phai la m6t he tuong tac, mem deo, tuong thich dua tren may tinh, dac biet dugc phat tri^n d^ h6 trg giai quye't cac vail d^ quan ly phi ca'u tnic nham hoan thien viec ra quy^t dinh No sir dung du lieu, cung ca'p giao dien tien dung va cho phep nguofi ra cac quye't dinh hi^u tha'u dao c6ng viec cua minh co th^ six dung no m6t each hieu qua
DSS cung sir dung cac m6 hinh (ca m6 hinh chu^n va m6 hinh tu dua ra) dugc xay dung trong qua trinh tuong tac thucmg xuyen ciia nguoi sir dung va
he th6ng de h6 trg tat ca cac giai doan ra quyet dinh, bao g6m ca co so tri thuc
1.2 Cac thanh phan ciia DSS [31
DSS dugc ca'u thanh tu cac he con sau:
He con quan tri dOf lieu He bao g6m mot (hoac nhieu) co so du lieu chua cac du lieu co lien quan de'n cac tinh hu6'ng dugc xem xet va dugc quan ly
bang m6t phan mem ggi la he quan tri ca sd die lieu (DataBase Management
Trang 130 ^ TAI NCKH CAP DHQGHN
He con truyen thong (he con h6i thoai) Ngudi sir dung co the' iruyen
th6ng bang each ra lenh cho DSS thdng qua he con nay No cung ca'p giao dien
ngUdi sit dung
He con quan tri tri thiifc He con tuy chon nay co ihi h6 trg cho bat cu he
con nao khac hoac m6t boat d6ng nhu m6t thanh ph^n d6c lap
NhOng thanh p h ^ nay tao nen thanh p h ^ phdn m^m ciia DSS Chiing dugc dat trong m6t may tinh va co th^ de dang sir dung nhof cac p h ^ ciing va
phSn mim b6 sung Ngu6i sir dung cung co th^ dugc xem nhu m6t thanh p h ^
ciia he th6ng Vi rang, nhu cac nha nghien curu da khang dinh, su dong gop ciia DSS chi CO th^ dat dugc nh5 su tuong tac giua may tinh va ngudi ra quye't dinh
DOT lieu: trong
; * Quan tri du lieu Quan tri m6 hinh
s z Quan tri tri thuc
I
Quan tri h6i thoai
I
Ngucd Quan ly (Ngucri su dung)
Hinh 1.1 MO hinh mure khai niem cua DSS
M6t m6 hinh muc khai niem ciia DSS dugc chi ra trong hinh 1.1 No cung ca'p m6t su hi^u biet co ban ve ca'u tnic chung va cac thanh phan cua DSS Mot cai nhin chi lie't hon ve m6i thanh phdn ciia no dugc gioi thieu rong cac phan tie'p theo
Trang 14Di TAI NCKH CAP DHQGHN
1.3 Cac thong con trong DSS [3]
1.3.1 He thong con quan tri dur lieu
H6 con quan iri du li6u duac tao thanh tur cac thanh p h ^ sau:
- Co so dulieu DSS
- H6 quan tri Co so dQ \itn
- Tit di^n du lieu
- Phuong tien truy \Sin
Nhung thanh p h ^ nay dugc chi ra trong so d6 hinh 1.2 Trong hinh cung chi ra m6'i tuong lac ciia he con quan tri du lieu vdi cac thanh phSn khac ciia DSS cung nhu su tuong tac vdi cac ngu6n dO: lieu khac
a Ca sa dU lieu
Mdt Co s6 du lieu (CSDL) la m6t tap hgfp du lieu co lien quan vdi nhau
dugc t6 chiic d^ dap ung dugc cac nhu cau va co ca'u ciia \6 chuc No co \hi
dugc nhilu ngudi sir dung cho nhi^u ung dung khac nhau M6t co so du lieu g6m nhi^u file rieng re cd md'i lien he Idgic vdi nhau dugc quan ly bang nndt he quan tri CSDL MOt file truyen thd'ng chiia cac thdng tin vl mdt ung dung Vi
du, mdt cdng ty cd th^ cd mdt file nhan su chiia danh sach nhan vien, mdt file khach hang chiia danh sach tat ca khach hang v.v Cac file dd cd th^ chiia cac
du heu nhu dia chi, sd dien thoai, sd lugng hang mua ciia mdi khach hang Trong mdl he thdng tin tin hgc hoa, mdt file cd the dugc luu tru tren cac ihie'i bi lini tru ngoai, vi du nhu bang tu, dia tiif Hinh 1.2 md la CSDL trong DSS cua
mot \6 chiic
Dii lieu trong cac CSDL dugc luu trir vdi mot su du ihua it nha'l de phuc vu cho nhieu ling dung Bdi vay Co sd du lieu la ddc lap vdi chuang irinh may tinh
sir dung nd va phan ciing luu tru no Co sd du lieu dugc to chiic cho cac file ciia
cdno ty dang idn tai, nhung chiing dugc lien ket theo each lao thanh mot don vi lich hgp Su sap dat nay la rat quan trgng khi thdng tin dugc cap nhat Hon nua,
nd cd the lie't kiem mdt each dang ke khdng gian luu tru
Du lieu trong CSDL DSS co the bao gdm ngudn du lieu trong, dir lieu
nooai va dii lieu rieng thudc mdt hoac nhieu ngudi sir dung Dii lieu trong :
Trang 15Di TAI NCKH CAP DHQGHN
nhan tiir he xir 15^ giao dich ciia t6 chiic, tuy thudc vao su c ^ thie't ciia DSS (he
h6 trg quye't dinh) du lieu co th^ bao g6m cac linh vuc chuyen mdn nhu: ke toan, tai chinh, tiep thi, sdn xudt, nhan su Du lieu giao dich la ngu6n thOng tin chinh ciia boat dftng trong c6ng ty M6t vi du tieu bi^u \i du heu nay la
bang tinh luong hang thang
Cac dQ heu khac cung la quan trgng d6i v6i DSS, vi du nhu : ke' hoach vi
ty le c6 tiic, ke' hoach lich bao tri may moc, cac du bao v^ doanh s6, chi phi cac khoan muc hao hut du tru va ke' hoach thue nhan c6ng trong tuong lai
Du lieu ngoai co th^ bao g6m dO lieu c6ng nghiep, du heu nghien cuii thi
tnicmg, du heu dilu tra dan s6, du heu thue nhan c6ng dia phuong, cac thay d6i v^ chinh sach ciia chinh j*ii, bi^u thue' hoac dQ heu kinh te' dSit nude Cac du
heu nay co th^ la'y tQ \6 chiic chinh phii, cac h6i thucmg mai, c6ng ty nghien
ciiu thi trucmg, c6ng ty du doan kinh te' va bang su c6' gang ciia chinh c6ng ty t6 chiic thu thap dQ heu tii ben ngoai Gi6'ng nhu dQ heu trong, dQ lieu ngoai co th^ dugc duy tri thu5ng xuyen trong CSDL ciia DSS hoac co th^ dugc cap nhap khi DSS dugc sii dung Trong m6t s6 truomg hgp dQ lieu ngoai co the dugc cung c9rp tQ cac dich vu may tinh true tuye'n
Du lieu rieng co th^ bao g6m cac luat dugc nhQng ngucri tao ra quye't dinh
cu th^ sir dung va su dinh gia ve trang thai va/hoac cac dQ lieu cu th^
Di tao ra m6t CSDL DSS c ^ thuofng xuyen tie'p nhan, b6 sung du lieu tu
cac ngu6n dQ lieu khac nhau
b He quan tri CSDL
M6t he quan trj CSDL (Database Management Systems - DBMS) thuc
hien ba chiic nang co ban la t6 chQc luu trie dQ lieu trong CSDL, phuc h6i du
lieu va kie'm soat viec truy xua't dQ lieu Cac tinh nang ciia DBMS trong DSS cung ca'p m6t each cha't lugng cac dQ heu cho boat d6ng ciia DSS
Luu tru: Nhieu he th6'ng may tinh Ion luu trQ nhieu file Ion, voi m6i file chiia nhi^u ban ghi, voi m6i ban ghi co nhi^u muc du lieu va v6i m6i muc nay lai chiia nhieu ky tu Kha nang luu tru cua he th6'ng may tinh bi gioi han boi khfing gian luu tru ca b6 nho chinh va b6 nha phu (nhan to nay ngay cang dugc khac phuc) Toan bg viec t6 chuc luu tru nay do DBMS dam nhiem
Trang 160 ^ TAI NCKH CAP OHQGHN
Ngu6n dQ
Trich nit du lieu
Phuong tien
truy v&i
Co sd dQ lieu h6 trg quye't dinh
• Tong ke't Bao cao
neng, canhan
Quan tri hoi thoai
Quan tri m6 hinh
Quan tri tri thiic
w< ix^
Hinh 1.2 He ihO'ng con quan tri dQ lieu
Truy xuat du lieu: DBMS trg giiip viec lay dQ lieu rat true quan d5'i vai
nguoi sir dung Cac DBMS hien hanh thuong ra't m^m deo cho viec khai thac
va hi^n thi thOng tin V6i mOt DBMS tinh vi, ngu&i sir dung co the dinh ro mot s6' xir ly dQ lieu va yeu cau 6 dSu ra ( chang han nhu cac bang bao cao hoac hinh anh d6 hoa)
Kiem soat truy nhap: IVhieu boat d5ng kiem soat cua DBMS khong true
quan d6'i v6i nguoi sir dung Nguoi sir dung chi dat cac cau hoi va nhan dugc th6ng tin tra loi ma kh6ng c ^ quan tarn den DBMS thuc hien xir ly nhu the nao DBMS co the dugc thiet ke hudng th5ng tin toi man hinh d6i voi m6i yeu cau va xac dinh rang (1) nguoi dua ra yeu cau phai la nguoi dugc phep, (2)
Trang 17O^ TAI NCKH CAP OHQGHN
ngudi c6 quy^n truy nhap vao file yeu c^u, (3) nguoi co quy^n truy nhap vao
cac muc dQ lieu yfeu cfiu trong file D6'i vdi m6l may tinh Idn, DBMS cd th^ thuc hien tSit ca cac chiic nang di^u khi^n m6l each hoan hao D6'i vdi cac may
tinh nho, DBMS cd thi chi thuc hien dugc mdt sd chQc nang Day la mdt linh
vuc ra't phat tri^n: cac DBMS thuong mai thuong ra't khac nhau va da dang
Ngudi quan tri cd th^ khai thac thdng tin tQ DSS 6 dang cac mlu bao cao dinh ky, cac bao cao dac biet va ddu ra ciia cac md hinh toan hgc Trong ca hai trudng hgp nay DBMS ddng vai iro nhu mdt ngudi giQ c6ng va tao ra ket qua tu cac dQ heu cd sSn DBMS cd the cung ca'p mdt ngdn ngQ tmy vaii ma ngudi
dung cd th^ thao tac d^ tao cac bao cao cu ihi khi sir dung cac chi din
Mdt CSDL hieu qua va su quan ly ciia nd cd the cung ca'p su hd trg cho nhilu boat ddng quan ly; hd trg cho mdt bd cac quan he du lieu khac nhau va phat sinh cac bao cao la vi du tieu bi^u Tuy nhien, kha nang thuc su cua DSS chi dugc cung carp khi CSDL dugc tich hgp vdi md hinh
c Phuang tien truy van
Tien ich truy vStn trong DBMS cung ca'p cac co sd cho viec tmy xua't dQ lieu: nd cha'p nhan yeu cSu dQ lieu (tQ cac thanh phin DSS), xac dinh each d^ cac yeu c5u nay cd th^ dugc hoan thanh (neu cdn thie't cd th^ tham khao tu di^n
dQ lieu), cdng thQc hoa cac yeu cin chi lie't va tra lai ke't qua cho ngudi dua ra
yeu ciu Tien ich tmy vaii bao gdm mdt ngdn ngQ dac biet (nhu SQL) Cac chQc nang quan trgng ciia mdt he thd'ng tmy va'n DSS la cac boat ddng " lua chon , thao tac va trinh diln " dQ heu
d Tirdien dulieu
Tu di^n dQ heu la mdt danh muc ciia tat ca dQ heu trong CSDL Nd chua dung cac dinh nghia du lieu va cd chQc nang chinh de tra Idi cho cac cau hoi ve tinh san sang ciia thanh phSn dQ lieu, nguon du lieu hoac ngu nghia chinh xac ciia dQ lieu Tu dien dQ lieu dac biet rat phii hgp cho qua trinh trg giiip giai doan thu nhap thdng tin de tao ra quye't dinh dugc xu ly thdng qua tmy xuat du lieu tu cac vung vah de cu the Tu dien dugc bo sung khi thuc hien viec tao mot thu muc khac, them thuc the mdi, xoa thuc the va khai thac thdng tin tren doi tugng cu the
Trang 180 ^ TAI NCKH CAP DHQGHN
1.3.2 He thong con quan tri mo hinh
He thd'ng con quan tri md hinh ciaa DSS gdm cac thanh phan sau day:
- Co sd md hinh
- He quan tri co sd md hinh
- Ngdn ngQ md hinh hoa
- Tir di^n md hinh
- Su thuc hien md hinh, tich hgp md hinh va lenh
Cac thanh p h ^ nay cung giao dien ciia chiing va cac thanh ph&i khac ciia DSS dugc chi ra d hinh 1.3
a Ca sa mo hinh
Mdt CO sd md hinh chiia dung cac quy trinh va cac md hinh ciia khoa hgc quan ly, tai chinh, thd'ng ke chuyen biet va thd'ng ke thudng xuyen, cac md hinh dinh lugng khac cung ca'p cac kha nang phan tich U-ong mdt DSS Kha nang truy cap, khdi ddng, thay d6i, phd'i hgp va ki^m tra cac md hinh la mdt kha nang chinh ciia DSS, nd khac vdi mdt he thd'ng thdng tin dua tren may tinh (CBIS) truyen thd'ng (nhu ITS va MIS) Cac md hinh trong co sd md hinh cd th^ dugc chia thanh cac loai chinh sau: chien luge, chie'n ihuai, tac nghiep va cac khdi xay dung md hinh, cac thii tuc con
Md hinh chien luge dugc sir dung d^ trg giiip nhiing ngudi cd irach nhiem lap cac ke' hoach chie'n luge quan ly d miic cao nha'l Cac ling dung tiem nang bao gdm viec phat trien cac muc lieu chung, ke hoach cho viec hgp nha'l va tie'p nhan ket qua, lua chgn phan bd viec san xua'l, phan tich su tac ddng tir mdi trtrdng va du tru ngan sach, ve vd'n ma khdng cd quy trinh cu the Cac md hinh chie'n luge hudng den mdt pham vi rdng rai, vdi nhieu bien dugc dien la trong mdt dang cd dgng Tam thdi thai gian cho cac md hinh nay irai ra trong nhieu nam
Cac md hinh chie'n thuat chu yeu dugc sit dung d miic quan ly trung gian
de hd trg viec phan bd va kiem soat cac tai nguyen cua id chiic Vi du ve cac
md hinh chien thuat bao gdm lap ke hoach ve nhu cSu lao ddng va lap ke hoach xuc tie'n ban hang, xac dinh bd tri san xua't va quy Irinh lap ngan sach Cac mo
Trang 190 ^ TAI NCKH CAP OHQGHN
hinh chi^n thuat thudng chi dugc Qng dung cho cac he thd'ng con cQa i6 chuc
nhu phong k^ toln Khoang thdi gian cho cac md hinh nay thay d6i tu mdt
thang tdi hai nam Tuy cd cSn de'n mdt sd dQ lieu ngoai nhung vi co ban cac
md hinh nay sir dung dQ lieu trong la chinh
Cac mo hinh (co so mo hinh)
• Chie'n luge, chie'n thuat, tac nghiep
• Ti^p thi, tai chinh, thd'ng ke, khoa hgc
quan ly, ke' toan, ky thuat
• Cac khd'i xay dung md hinh
Tijr dien mo hinh
Quan tri co so dur lieu mo hinh Cac lenh md hinh hoa: (tao) Bao tri va cap nhat
Giao dien co sd du lieu Ngdn ngQ md hinh hoa
Ttr
Quan tri dQ lieu
Thuc hien md hinh, tich hgp md hinh va bd xir ]y
Ben canh cac md hinh chie'n luge, sach luge va cac md hinh boat ddng,
md hinh co sd cd the' chua khd'i xay dung md hinh va cac phin tac vu thudng xuyen Vi du, cd the bao gdm "bd sinh sd ngau nhien"', " Tinh toan gia tri quy ddi ve hien tai" ," phan tich hdi quy" Cac khd'i xay dung nhu the' dugc sir dung
Trang 200 ^ TAI NCKH CAP DHQGHN
theo nhidu each Chiing cd th^ dugc sir dung tren cac Qng dung rieng nhu phan
tich do lieu Chung cd ihi dugc sir dung nhu cac thanh phdn ciia cac md hinh Idn hon Vi du, thanh p h ^ quy doi ve gia tri hien tai cd the' la mdl phSn ciia md
hinh "Lap ke' hoach mua ban cho tuong lai" Mdt vai khd'i xay dung nay dugc
sir dung di xac dinh hdi quy cac gia tri va cac thdng sd trong mdt md hinh
Oiang ban, viec sii dung phan tich hdi quy tao ra cac dudng xu the' trong mdt
md hinh du doan Chung thudng xuyen hen quan de'n cac chuc nang xay dung mdhinh
Cac md hinh trong co sd md hinh cung cd th^ dugc phan loai theo cac linh vuc chQc nang (tai chinh, ki^m soat san ph^m, ke' loan, ) hoac theo cac nguyen tac xay dung (cac md hinh thd'ng ke, cac md hinh phan bd ciia khoa hgc quan ly) Danh sach cac md hinh dugc quan ly trong iQ di^n md hinh Sd lugng cac
md hinh trong DSS cd ih^ thay d6i tQ mdl vai md hinh cho de'n vai tram md hinh Vi du, mdl DSS cho cdng ly van lai Idn bao gdm tren 175 md hinh(xem Oliff [1984])
Cac ngdn ngQ md hinh: Mac du mdt vai md hinh trong co sd md hinh da
dugc vie'l ra iQ irudc; viec vie'l md hinh thudng xuyen la c ^ thie't Diin nay cd thi dugc thuc hien vdi ngdn ngQ bac cao (COBOL) hoac cd ih^ id't hon vdi cac
ngdn ngQ the' he ihQ tu (4 GL) va cac ngdn ngQ md hinh hoa dac biet
b He quan tri ca sa mo hinh
He quan tri co sd md hinh la mdl he thd'ng phdn mem vdi cac chuc nang sau : Tao md hinh, sir dung cac chuong trinh con va cac khd'i xay dung khac; viec tao ra cac cdng viec va bao cao mdi; cap nhat va thay d6i md hinh; va thao tac dQ lieu ciia MBMS la kha nang tuong lac cac md hinh vdi cac lien ke't thich hgp thdng qua mdl co sd dQ lieu
c Tirdien mo hinh
Vai ird ciia Tu dien md hinh gidng nhu tu dien ciia CSDL Nd la mot ban danh sach ciia la'l ca md hinh d trong co sd md hinh Nd chua dung cac dinh nt^hla md hinh va cac chuc nang chinh ciia nd la tra Idi cac cau hdi ve kha nang
va tinh sSn sang ciia cac md hinh
Mdl dieu ihii vi dua ra trong mdt sd DSS la "md hinh nao nen dugc su duno cho trudng hgp nao? " Su chgn lua md hinh nhu vay khdng the thuc hien
Trang 21O^ TAI NCKH CAP OHQGHN
dugc bang MBMS bed vi nd ddi hoi cd su thanh thao; dd chinh la linh vuc tiim
nSng cho mdl thanh phSn tri thQc "hd trg" cho MBMS
d Thuc hien, tich hap mo hinh vd lenh
Cac boat ddng sau day ludn dugc bd phan quan tri md hinh ki^m soai:
- Thuc hien ki^m soat su van hanh ciia md hinh
- Md hinh tich hgp boat ddng cQa mdt vai md hinh khi cin thie't ( hudng d^u ra ciia mdt md hinh dugc xir ly bang mdl md hinh khac)
- Mdt md hinh v^ bd xir ly lenh dugc sir dung d^ tie'p nhan va hi^u dugc lai heu cung cStp cho md hinh cho phep dua ra ben ngoai thanh ph^n hdp hdi thoai va cdng viec nay la c ^ thie't cho ca MBMS, md hinh thuc hien hoac chQc nang tich hgp
- Su tinh loan thuc hien cung vdi yeu cdu phuc hdi thanh phSn dQ lieu md hinh tQ DSS ciia CSDL hoac tQ mdt CSDL khac Diin nay la hnh boat va
thuc hien xuyen sud'l mdt giao dien CSDL
1.3.3 He thdng con tri thiifc
Nhieu va'n d^ vi phi ca'u tnic va ban ca'u tnic la rat phQc tap vi chung ddi
hdi phai cd su hi^u bie't ciia chuyen gia cho giai phap d^ b6 sung vao cac kha
nang quen thudc ciia DSS Nhu vay, su hieu bie't chuyen gia cd thi dugc cung cSip bang he chuyen gia Do dd mdl DSS lien tie'n can dugc irang bi mdl thanh
p h ^ ma chung la ggi la he quan tri tri thuc Thanh p h ^ nay cd the cung cap
kie'n thQc chuyen mdn d^ giai quye't mdt sd khia canh ciia vSin de va /hoac cung cap tri thQc d^ tang cudng boat ddng cua cac thanh p h ^ DSS khac Thanh phan Quan tri tri thQc bao gdm mdt hay nhilu he chuyen gia Gidng nhu thanh phan Quan tri dQ lieu va quan tri md hinh , phan mem quan trj tri thQc cung ca'p su thuc hien va lich hgp cdn thie't ciia he chuyen gia Mdl he thdng hd trg quyet dinh cd th^ bao gdm mdl thanh phSn nhu vay la mdt DSS thdng minh, mot DSS/ES hoac DSS co so tri thuc
1.3.4 He con giao dien hoi thoai ngudi sir dung
Thanh phan hdi thoai ciia mdt DSS gdm phan mem va phan cung cung
ca'p eiao dien cho ngudi dung DSS Thuat ngu Giao dien nguai dung bao triim
Trang 220 ^ TAI NCKH CAP OHQGHN
cac khia canh vi tniy^n thdng giua ngudi sir dung va DSS Nd bao gdm khdng
chi p h ^ cQng va phfln m^m, ma con bao gdm cac ye'u td' cd hen quan tdi tinh
di sit dung, kha nang truy nhap va ca su tuong tac giQa may va con ngudi Mdl
sd chuyen gia DSS cho rang, Giao dien ngudi dung la thanh phin quan trgng
nhSft bdi sQc manh, dd m^m deo va cac dac tinh de su dung ciia DSS nhan dugc
tQ cac thanh ph^n nay (Xem Sprague va Carlson[1982, p.29])
Mdt giao dien ngudi dung khdng tien Igi la mdt trong nhiing ly do chinh tai sao ngudi quin ly da khdng sir dung may tinh va cac phan lich dinh lugng d^ md rdng nang luc ciia minh mac du cac cdng cu da san sang
Quan tri cua he thd'ng con hoi thoai
He thdng con hdi thoai da dugc quan ly bang phSn mim ggi la he thdng
tao sinh va quan ly hdi thoai (DGMS) DGMS gdm mdl sd chuong trinh cho nhung kha nang dugc liet ke trong bang hei ke tinh nang ciia DGMS DGMS khdng chi dugc bie't nhu la mdt he thd'ng quan tri giao dien ngudi su dung ma cdn cung ca'p nhilu tien ich khac,
Xii ly hoi thoai
Qua trinh hdi thoai ciia mdt DSS dugc chi ra d trong so dd 1.3 Tuong tac giQa ngudi dung vdi may tinh qua mdt ngdn ngQ da dugc xu ly bang DGMS Trong mdt he trg giup tien tie'n thanh p h ^ hdi thoai bao gdm mdl bd xu ly ngdn ngQ tu nhien DGMS cung ca'p cac kha nang da dugc chi ra trong bang dudi day, lam cho ngudi dung cd kha nang tuong tac vdi he con quan tri md hinh va he con quan tri dQ heu
He con quan tri hdi thoai dua ra mdt he giao dien ngudi su dung, nd bao edm cac thie't bi vao - ra va cung ca'p cac phuong lien vat ly cho viec truyen thdng vdi DSS; mdt chiic nang ki^m soat ludng thdng tin di qua he hdi thoai nhu dir lieu da dugc cap nhat va xua't ra, vdi mdt chiic nang chuyen doi du lieu vao ciia ngudi diing trong cac ngdn ngii ma DBMS cd the doc dugc
Trang 23O^ TAI NCKH CAP OHQGHN
Bang hetke tinh nang chinh cua DGMS
• Tuong t6c theo mdt vai mhi hdi thoai khac nhau
• Khai thac, luu trQ vaphSn tich cac dudng hdi thoai(luu vei), nd cd the dugc s6 dung d^ Ci^i thien he thd'ng hdi thoai
• LJtfn cho n ^ d i dOaig quen vdi su da dang cQa c^c thie't bi ddu vho
m Bieu dien dQ heu theo khudn dang da dang ciia cac thi€it bi ra
• Cung cSp cac kha nang trg giup, thuc d^y, chin doan va nhung quy trinh
god 5^ hoac su trg giup linh boat khac
• Cung cS(p giao dien ngudi diii^ ddi vdi CSDL va co sd md hinh
• Tao ra cku trik dQ lieu tdi dinh dang dQ lieu ra (md t4 dQliSu xu^i)
• Cung c^p dd hoa mitu, dd hoa khdng gian ba chi^u v i dQ lieu md ph6ng,d6
• Cd c ^ ciia s6 cho ph6p nhilu chQc nang c^ the eung hien thi mdt iuc
• Go t h ^ i ^ trg tnay^n thdng giQanguci sudung vi ngu xay dung DSS
• Cung cSfp viec dao tao qua vi du(chi din iigudi diing thdng qua cai vao qua
trinh n^Miinh hoa)
• Gung cSp linh m€m deo va thich nghi sao cho DSS se cd kha nang ihich
nghi vdi cac v ^ d^ khac nhau \ ^ cdngughe
1.3.5 Ngudi sii dung
Ngudi la da phai ddi mat vdi cac va'n de hoac cac quye't dinh ma DSS dugc thie't ke' de hd trg giai quye't chung Tuy nhien cd tdn lai su khdng ddng nha'l giQa ngudi tham gia xay dung DSS va ngudi su dung nd Cd nhung su khac
nhau nha'l dinh vi cac vi tri lam viec ciia ngudi su dung, each dat den mdt
quye't dinh cud'i cung, su ua thich va kha nang cQa ngudi su dung DSS de di de'n mdl quyet dinh (ki^u ra quyet dinh)
Cd hai Idp rdng rai nhQng ngudi dung DSS: Ngudi quan tri va ddi ngu chuyen vien NhQng ngudi nay, gidng nhu cac nha phan lich lai chinh, nhung ngudi lap ke hoach san xua't va ngudi nghien cuu thi trudng Lay ra mdt sd ngudi quan tri thi cd khoang hai den ba ngudi sir dung may linh vdi cudng do Idn Bie't dugc ai la ngudi ihuc su phai sir dung DSS la rat quan trgng khi ta dan'' thie't ke nd Ndi chune, ngudi quan tri mong dgi he thdng se ird nen su dun" than thien hon so vdi ddi ngu chuyen vien Ddi ngu Chuyen vien hudng tdi su chi tiet hon, va mong mudn mgl he thdng phiic hgp cho cdng viec hang
Trang 24DI TAI NCKH CAP OHQGHN
ngay ciia ho, va quan tarn de'n kha nang linh loan ciia DSS Trong nhi^u imdng
hgp nhung chuyen vien phan tich la tmng gian giQa ngudi quan tri va DSS
Quan tri dQ lieu va
DBMS' Quan Iri tri thQc
Quan tri md hinh
DAURA Ng6n ngii hien thi
Ngudi diing I
May in, so d6
Hinh 1.4 He con giao dien hoi thoai
Trong ddi ngu ciia nhQng ngudi quan ly va cac chuyen vien cd nhung bd phan cd anh hudng quan trgng den thie't ke DSS Vi du, nhQng ngudi quan ly d cac mQc khac nhau, cac linh vuc chuc nang khac nhau, irinh dd dao tao rat cdn thiet d^ hd trg viec phan lich
1.3.6 Phan mem va phan cung cua DSS
He hd trg quye't dinh phat trien ddng thdi ciing vdi su lien bd trong cdng nehiep phan ciing va cdng nghe phan mem may tinh Phan cung lam anh hudng tdi chQc nana va tinh de su dung ciia DSS Mac du vay, viec lua chgn giai phap phan Cling cd the xay ra truoc khi, trong khi hoac sau khi xay dung phdn mem
Trang 25O^ TAI NCKH CAP OHQGHN
DSS Trong mdt sd trudng hgp su lua chgn p h ^ cQng da xac dinh trudc nhQng cai dugc c h u ^ bi san trong t6 chQc Mdt DSS cin boat ddng tren mdt ca'u hinh phdn cQng chu^n
Thanh phSn chinh ciia phSn cQng la mang chia se thdi gian, may tinh Idn
ciia t6 chQc, may vi tinh, may linh ca nhan hoac mdl he thd'ng phan tan Mdi tuy chgn cho ta nhQng thuan Igi va nhQng ban che NhQng diin nay se khdng
nhac tdi d day
Trang 26CHUONQII
NHONG V&N OE CUA KE HOACH CHIE'N LUOC
GIAO THONG VAN TAI VA CAC MO HINH CUA NO
Do tinh cha[t ciia boat ddng nghep vu, Vien Chien luge Giao thdng Van lai
c ^ su dung nhi^u phuong phap md hinh va cdng cu may tinh d^ trg giup cho boat ddng ciia minh Tuy nhien , viec su dung cac cdng cu nay cdn mang linh don chiec va rSit ban che Mdl he trg giup quye't dinh dem lai hieu qua thie't thuc cho boat ddng lap ke' hoach va xay dung chie'n luge la mdt mong mudn ciia vien
Viec xay dung mdt he trg giup quye't dinh chung chung la khdng thd Di cd th^
xay dung dugc mdl he trg giup cho cac hgat ddng ciia vien, ta cin phai nghien
cQu boat ddng ciia ho di biet dugc hg cin mdl he trg giup quye't dinh nhu the'
nao Hai ndi dung co ban hen quan de'n cac trg giup cin dugc nghien cuu:
• NhQng md hinh, xu ly nao thudng dugc su dung?
• Quy trinh cho mdi boat ddng lap ke' hoach dien ra nhu the' nao?
• He trg giup se cung cip cac md hinh theo yeu ciu cdng viec va phu hgp vdi cac tie'n trinh cd th^ cd ma hg thudng su dung
2.1 Bai toan dat ra cho ke hoach chien liroc giao thong van tai
Trong ndi dung ciia chie'n luge phat trien giao thdng van lai den nam 2010,
2020 cd hai nhiem vu quan trgng la phat tri^n mang ludi giao thdng va cac loai hinh phuong tien van tai thich hgp trong luong lai Vaii de dat ra la:
- Mang ludi giao thdng van tai ciia nude la vao nhQng nam 2005 va nam
2010, 2020 phai dugc phat tri^n nhu the nao d^ khdng nhung dam bao
ma cdn phai di truoc mdt budc ve co sd ha ting, dap Qng dugc nhu ciu phat iri^n kinh te' va xa hdi ciia nude ta vao nhung nam dd va nhung nam liep theo
Vdi mang ludi giao thdng dugc xay dung vao nhQng nam dd, nhung loai hinh phuong lien nao vdi nhiing dac tinh ky thuat gi va quy md ra sao cin dugc su dung d^ dam bao yeu ciu van tai hang boa va hanh khach trong loan qudc va tren mdi dia ban sao cho dat hieu qua cao nhat (vira
Trang 270 ^ TAI NCKH CAP OHQGHN
cd tinh kinh t6', vua van minh va hitn dai phu hgp vdi di^u ki6n Viet
nam)
Giai quyfe't cac bai loan ntu ra trfen day, ngudi ta phai di d6'n xay dung cac
klf hoach phat triln giao thdng van tai bao gdm ca mang ludi giao thdng va cac plaiong tien van hanh tren nd cho cac thdi ky vdi cac md'c la 2005, 2010, 2020
D^ cd thi dua ra dugc cac k€ hoach dai han cSn tap trung vao du bao nhu cau vl
van tai hang hoa va hanh khach khdng chi theo dia phuong, khu vuc, loan qudc
ma cdn theo cac loai hinh phuang tien, cac ludng, tuye'n c ^ quan tam Qua nhirng con sd' du bao thu dugc cd th^ d^ xua't cac phuang an nang ca'p, md rdng
va xay dung mdi cac tuye'n dudng, cac dSu mdi giao thdng, phat tri^n cac loai hinh phuang tien, cac trang thie't bi khac nhau va dua vao sir dung mdt each hieu qua cho mdi thdi ky Vdi nhiing ly giai tren, cd th^ iha'y rang, cac du bao van tai
la nhiing vien gach ndn tang cho viec xay dung cac chie'n luge va ke' hoach phat tri^n nganh giao thdng van tai Nhung bai loan du bao, tie'p dd la cac bai loan ke' hoach la nhung ndi dung co ban ma cac don vi nghien ciiu chie'n luge ciia nganh giao thdng van tai phai thuc hien vao nhiing thdi ky nhat dinh trong mdi giai doan
2.2 Nhihig van de phirong phap luan cua du bao van tai
De cd CO sd cho viec phat tri^n mang ludi giao thdng cung nhu phat iri^n cac loai phuang lien van tai ngudi ta can phai bie't dugc nhu cau van lai ciia nhiing thdi ky sap tdi (bao gdm ca van tai hang hoa va van tai hanh khach) Cac nhu can dd trong tuong lai cd dugc nhd cac du bao
2.2.1 Cac noi dung da bao ve nhu cau van tai
Du bao \i nhu cSu van tai bao gdm hai nhdm: nhdm thii nhat la du bao ve
van tai hang hoa, nhdm thii hai ve van lai hanh khach
V^ nguyen tac, ddi vdi cac giai doan cang dai cac du bao cang gdp cang cho ket qua hgp ly han Cac du bao gdp thudng cho d6 chinh xac cao hon vi no chi phu thudc vao mdl sd it cac nhan id, cac chi lieu (thudng cung la chi lieu gdp Idn) Tuy nhien, neu chi dung d cac du bao gdp thi kh6ng the dap ling dugc yeu cau dat ra Cho nen, trong mdl chung muc cd the dugc can phai nghien ciiu cac
du bao chi lie't hon - cac du bao theo phuang thiic van tai theo tuyen dudng va cac dau mdi giao ihdng chinh- cho phu hgp vdi yeu cau va muc lieu de ra ban
Trang 280 ^ TAI NCKH CAP OHQGHN
diu (ph^t tri^n mang giao thdng va dinh hudng su dung phuong tien thich hgp) Viec lam nay gap phai rat nhi^u khd khan, vi ring, cac du bao cang chi lie'i hon cang yeu ciu nhi^u thdng tin hon Viec thu thap cac thdng tin cin cho cac du bao loai nay thudng tdn k^m va mQc dd chinh xac cdn nhi^u vin de phai xen
xet Tuy nhien, cdng vide nay hien nay la hoan loan cd thi thuc hien dugc va
viec nghien cQu d^ xuit phuong phap cung nhu quy trinh cdng nghe cho boat ddng du bao van tai luc nay la rit cin thie't ddi vdi nhu ciu su dung hien nay cung nhu trong nhung nam tdi Viec dua ra cac quy trinh du bao va lua chgn cac
md hinh du bao thich hgp se cho phep nhanh chdng cung cip cac du bao mdi v^ giao thdng van tai, mdi khi cd su di^u chinh trong quy hoach phat tri^n hay cd nhQng thay d6i trong chien luge phat tridn ciia dat nude [14],
a, Cdc du bao ve van tdi hang hod
dl Nhu cau van tdi hang hod
Nhu ciu van lai hang hoa la khoi luang hang hod cdn chuyen tra trong
mdt khoang thdi gian nhit dinh, tren mdt pham vi nao dd bing cac loai phuong lien nha'l dinh Khi tinh de'n su di chuyen tmng binh ciia cac khd'i lugng van lai
trong khdng gian ta cd nhu ciu v^ khoi luang hang hod ludn chuyen
Do nhu ciu ciia san xuil, ciia lieu diing ciia dan cu va nhu ciu xay dung phal tri^n kinh te', xa hdi trdn mdi dia ban, mdi khu vuc hay vung lanh thd ma d
dd cd nhQng nhu ciu khac nhau v^ cac chiing loai hang hoa khac nhau Chang ban nhu nhu ciu luong thuc, thuc pham, nguyen vat heu, thie't bi, phuong lien, ma d chinh khu vuc nay khdng san xuat dugc hay khdng cd dii de dap Qng Vi vay, nhQng nhu ciu nay cin dugc dap Qng bang each chuyen ird hang hoa lu cac noi khac den Tuy thudc vao mang ludi giao thdng giQa khu vuc nay vdi cac khu vuc cd hang hoa, vao cac loai phuong lien boat ddng tren cac luye'n
va dieu kien ihuan Igi ciia boat ddng giao thdng tren mang, vao kha nang ciia ngudi cd hang hoa va cung ling hang boa ma mot khdi lugng hang boa nao dd theo cac nhu ciu se dugc chuyen ird va phan bo theo cac loai phuong tien khac nhau
Nhiino yeu id lac ddng len khdi lugng hang hoa dugc van chuyen la rat da dano va ihudns xuyen thay ddi Tuy nhien, su hinh thanh len khdi lugng bang boa duoc van chuyen do sir chi pbdi ciia rit nhieu cac yeu id, nhung qui luat va
Trang 29O^ TAI NCKH CAP OHQGHN
phuong thQc rieng ciia nd Chinh su vi the' cd th^ du bao nhu ciu van tai dua iren cac ye'u td tac ddng de'n nd va cac quy luat dugc hinh thanh
Du bao tdng khd'i lugng van tai hang hoa, hanh khach
Theo viing TTieo tuyen I
Theo phuang lien
1
Du bao tieu diing - xuit khiu san phim chinh theo diu mdi
Du bao san xuit - nhap kh^u San ph&i chinh iheo
So dd 1 Tie'n trinh tien hanh cac du bao ve van tai
Ndi dung du bao nhu ciu van tai hang boa bao gdm cac du bao sau (so dd
a2 Khdi lugng van tai hang hoa ndi chung
Tdn*' khdi lugng van tai Tdng khdi lugng van tai dugc chia ra:
Khdi lugng van tai ngoai nude
Trang 30Di TAI NCKH CAP OHQGHN
- Khd'i lugng van tai trong nude Khdi lugng van tai trong nude lai cin chia ra:
• Khd'i lucmg van tai lien viing
• Khd'i tugng van tai ndi vung (bao gdm cac vung va cac dia phuang)
a3 Khoi luang van tdi chia theo cdc phuang thixc (nganh van tdi)
a4 Khoi luang van tdi tren mot sd luong tuyen chinh
Cac ludng, tuye'n dugc lua chgn d^ du bao bao gdm cac tuye'n Bac-Nam, mdl sd tuye'n tren dia ban Mi^n Bac va Mi^n Nam giiia cac thanh phd Idn, cac trung tam ciia cac khu vuc, cac khu cdng nghidp tap trung Tuy nhu cau va kha nang cd th^ chgn sd tuye'n cdn du bao nhilu hay it
b Cdc du bao ve nhu cau van tdi hanh khach
Nhin chung, cac du bao v^ van lai hanh khach cung tuong tu nhu ddi vdi van tai hang hoa (xem hinh 1) Tuy nhien, do dac thu ciia viec hinh thanh cac viing va tu di^m dan cu, nhu c£u di lai cdn phu thudc vao nhieu nhan id khac so
vdi nhu cin vi van tai hang hoa, nhu thu nhap dan cu, dieu kien ha tang, nhiing
boat ddng kinh te', xa hdi diin ra theo thdi gian, trong khdng gian, theo tmyln thd'ng van hoa, thdi lie't khi hau tirng viing Cho nen, cac du bao ve van lai hanh khach cd su khac biet nhat dinh so vdi nhu cau du bao hang hoa Chang han,
nhu cin van tai hang hoa trong cac thanh phd Idn khdng phai la van de phai
quan tam nhieu, thi viec van tai hanh khach trong thanh phd lai la van de dac biet quan tam
bl Nhu cau van tdi hanh khach
Nhu cin van tai hanh khach (NCVTHK) la sd lugng ngudi (HK) cin phai
chuyen cho trong khdng gian (HKKM), vdi nhiing khoang ihdi gian nhat dinh
de phuc vu cho cac boat ddng kinh le, quan su, chinh tri va xa hoi
Trang 31D i TAI NCKH CAP 0HCX5HN
NCVTHK dugc chia lam hai loai: nhu cau chU quan vd nhu cau khach
quan Nhu cdu khach quan la nhu cSu khdng phu thudc vao ban than con ngudi
tham gia vao boat ddng van lai ma do didu kidn mdi trudng xung quanh qui dinh
va tuong ddi 6n dinh Nghia la, du hoan canh kinh te' xa hdi cd thay d6i trong
mdt pham vi nao dd, thi cac nhu cin nay thay d6i khdng dang ki Chang ban,
ngudi Idn phai di lam, hgc sinh phai den trudng, thuong nhan phai di mua ban Dii trdi mua hay nang, mua ddng hay mua he cdng vide vin phai dien ra Nhu
cin chii quan khdng mang tinh chat bat budc, ngudi tham gia van tai cd the lien hanh hoac khdng, cd Ihi chuyen lit thdi di^m nay sang thdi di^m khac Khi hoan canh thay d6i, nhu cin nay cd th^ tang hay giam rix rd rang Dd la cac nhu cau
\i tham que huang, du lich, nghi mat, le hdi, te't nhil, Khi kinh te' suy giam, an loan trat tu xa hdi kem, cac nhu cin nay giam di nhanh chdng Nam dugc ban chSit hai loai nhu cin nay chiing ta c ^ phan tich ky cang trudc khi du bao
NCVTHK tren mdi ludng hay khu vuc
Du bao NCVTHK dua tren ba can cii:
- Nguyen nhan vd nai phat sinh ra cung cau
Nguyen nhan chinh phat sinh NCVTHK la su phat tridn kinh te', xa hdi, su phat tri^n va phan bd lai dan sd, cac truyin thd'ng phong luc tap quan dan idc
Noi phat sinh ra cung cin chii ye'u phu thudc vao su phan bd dan cu va phan bd
cac boat ddng kinh te' xa hdi dugc diin ra
- Khd nang cung- cau:
Kha nang cung cin chii ye'u phu thudc vao t6ng san ph£m xa hdi/dau ngudi, chinh sach phal tri^n giao thdng van tai, lugng vd'n din tu vao GTVT, du
lich va dich vu khac
- Mdi quan he giita cdc hoqt dgng kinh te, xa hoi trong khong gian, thai gian
Md'i quan he nay chii yeu phu thudc vao dia ly (dia hinh, khoang each), thdi tiet, chinh sach kinh te ciia da't nude, phan bo tai nguyen khoang san, phan
bd viing kinh te, su phal trien cac nganh kinh le tren mdi khu vi;c, mdi quan ht
hgp tacT giiia cac dia phuang, sd lugng cac danh lam thdng canh va noi nghi mat
NCVTHK thudng chia ra ba loai:
- CVTHK tren viing lanh thd
Trang 320 ^ TAI NCKH CAP OHQGHN
" NCVTHK theo tOng nganh van tai
" NCVTHK tren tOng tuy^n trong ludng
Viec phan biet ba loai NCVTHK chi la tuong ddi, thuc chit chung cd md'i quan he khang kbit lin nhau Bdi vay, khi tie'n hanh du bao khdng th^ tie'n hanh tQng phin rieng biet ma phai ti^n hanh can ddi coi dd la ba thanh phin trong mdt he thd'ng
b2 Du bao so lugng hanh khach noi chung thu&ng bao gom:
- T6ng lugt hanh khach, trong dd:
- T6ng lugt hanh khach ngoai nude
- T6ng lugt hanh khach trong nude, trong dd
- T6ng lugt hanh khach di lai tren mdi dia ban, bao gdm:
+ Trdn cac vung, dia phuong + Trong mdt sd thanh phd Idn
- T6ng lugt hanh khach lien vung
bS Du bao so luang hanh khach theo mot so phuang thiec vd tren cdc luong, tuyen chinh
- Theo dudng bd
- Theo dudng sit
- Theo dudng sdng
- Theo dudng hang khdng
- Theo dudng bi^n va theo limg ludng, tuye'n cu ih^ dugc xet
2.2.2 Cac dieu kien, tien de cho cac du bao
Van lai la mdl nganh dich vu nhim dap ung nhu ciu van tai de phat trien kinh le, xa hdi va an ninb qudc phong Vi vay, khac vdi cac du bao loai khac, no phu thudc rit Idn vao chie'n luge phat trien kinh te xa hdi ciia dat nude, ciia cac nganh, cac vung va su phat iri^n ciia kinh te ddi ngoai NTiung nhan td ke ra tren
Trang 33O^ TAI NCKH CAP OHQGHN
day lai thudng cd nhiiu kha nang, va vdi thdi gian cang dai cang de cd thay ddi
do y dd phat tri^n mang tinh chii quan ciia Chinh jAQ cin cd nhQng dieu chinh
khi xem xet diin kien cu th^ mdi thdi ky hoac do cac di6u kidn khach quan
khac Vdi dac tinh nhu vay, cac du bao dugc tie'n hanh theo kich ban la phu hgp
Vi vay, cac dQ lieu cung cin dugc chuin bi, thu thap theo nhi^u kha nang, nhidu
tinh hudng Di cd th^ du bao nhQng ndi dung ndu ra cin cd cac diu vao la cac
du bao chung vi phat tri^n kinh te' ciia dit nude (trong dd cd tinh de'n tOng vung)
cung nhu cac quy hoach phat tri^n kinh te' ciia cac nganh va cac vung da dugc nha nude va dia phuong thdng qua, qua trinh hdi nhap va phal tri^n ciia boat ddng kinh te' ddi ngoai Cac thdng tin lien quan de'n cac vin d^ neu ra d tren cang phong phu cang cho phep thu dugc cac du bao cang chinh xac va tin cay
Cu th^, cac thdng tin sau day (ciia cac nam da qua va ciia thdi ky du bao) la cin Ihi^t:
- Dan sd tmng binh ( ca nude va cac dia phuong)
- GDP va GDP cac nganh gdp Idn (ca nude va dia phuong)
- Cac phuong an diu tu va tidu dung
- Hoat ddng xuit nhap khiu va diu tu nude ngoai
- Quy hoach phat tri^n cac nganh kinh te' (loan qudc va vung lanh lh6)
- Mang giao thdng theo quy hoach phat tri^n
- Sd lieu v^ van tai hang hoa va hanh khach cac nam da qua ciia ca nude, cac dia phuong, cac thanh phd Idn, sd lieu van tai phan theo cac loai phuong lien va cac ludng tuyen, qua cac diu md'i giao thdng
- Cdc so lieu bd sung: sd lidu dieu ira cd the cd vi cac linh vuc tren va dac
biet v^ boat ddng giao thdng van tai va sd lidu tuong ung ciia mdt sd nude cd nhQng dieu kidn tuong tu dugc nhin nhan theo mdt each nao dd Cac chinh sach hoac y dd chien luge cd the cd tac ddng Idn den nhung nhan id neu ra d iren, chang ban nhu chinh sach giam din td'c dd tang dan sd, chinh sach phan bd dan cu nhim giam thieu tdi da qua trinh di dan tu ndng thdn ra thanh thi,
Trang 340 ^ TAI NCKH CAP OHQGHN
2.3 Cac mo hinh va phirong phap dii bao van tai
Hien nay trfin th^ gidi cac nha khoa hgc da d^ xudng hang tram phuong phap du bao khac nhau Cd phuong frfiap du bao chung dung dugc cho nhieu nganh, cd phuong phap chi dung trong chuyen nganh
Sau day se gidi thieu cac md hinh va phuong phap thdng dung nhit va cung
thudng dugc sQ dung trong cac du bao vi giao thdng van tai
2.3.1 Mo hinh ngoai suy
Md hinh ngoai suy don gian la ngoai suy theo day thdi gian TQ day sd qua khQ ciia mdt dai lugng cin du bao (nhu khd'i lugng hang boa van tai ca nude,
vung), cd thi xay dung ham hdi quy ciia nd theo thdi gian cd dang y=f(i) trong
khoang thdi gian cd sd lidu qua khQ[lo,t,l Sau khi ki^m tra cac di^u kien cin thie't ma ham f(t) tbda man, cd th^ su dung nd d^ du bao cho dai lugng dugc xet vdi cac thdi di^m t >t, vdi mdt dd chinh xac nao dd V^ nguyen tac, khoang thdi gian [t,,t] cin thie't d^ dam bao cho cac du bao dii tin cay khi ma [l,,ll < 2/3x[lo,tj] Cho nen, day sd cang dai cang cho phep du bao tuong lai xa hon
Md hinh ngoai suy phQc tap hon la cac ham hdi quy, tuong quan Dac biet
la hdi quy da nhan td Trong trudng hgp nay, cin xay dung dugc mdt ham luong quan ciia mdt dai lugng cin du bao y vdi mdt hay mdl sd cac dai khac cd mdi quan he nhit dinh vdi y, chang ban Xp Xj, ,x^ Tu cac day sd lieu qua khQ ciia y
va cac day sd lieu tuong Qng cQa cac dai lugng x xac dinh mdt ham luong quan:
y = f(xl,xl, ,xn))
Ne'u ham f() thoa man cac diin kien ddi hdi ddi vdi nd - chang ban nhu
ihoa man cac lidu chuin thdng ke, cac dai lugng dugc xet phai thuc su cd md'i quan he tuong quan vdi dai lugng cin du bao, - thi nd cd the' sir dung de du bao dai lugng y d mdl thdi didm tuong lai bing each thay cac gia tri tuong Qng ciia cac dai lugng x°=( Xj^ , Xj^ ,x^°) vao ham du bao se cd dugc gia tri du bao dai lugng y d thdi di^m cin dugc xet vdi dd sai sd nao dd:
y = l ( X i , X] v"9^n )
Trono md hinh nay, ngoai day sd heu ciia y, la can cd day cac sd lieu tuong uno ciia cac dai lugng x Them vao dd, neu sd cac dai lugng x, cang nhidu tbi
Trang 350 ^ TAI NCKH CAP OHQGHN
cic day sd lieu theo thdi gian phai cang dai mdi dam bao viec udc lugng ham f()
la thuc su cd y nghia Cung nhu trudng hgp tren, khoang thdi gian tuong lai cd th^ cho cac du bao tin cay trong trudng hgp nay cung khdng vugi qua 1/3 khoang thdi gian qua khQ ma cac day sd cd dugc sd lidu Vi vay thudng yeu ciu
vi dd dai ciia cac day sd' y cung nhu x
Ban chit ciia phuong phap la su dung quy luat phat iri^n ciia ddi lugng
trong qua khQ va hidn tai d^ suy ra su phat tri^n ciia nd trong tuong lai Diin nay
chi cd th^ dung khi su phat tri^n ciia ddi tugng trong qua khQ cdn tuong ddi 6n dinh de'n tuong lai, va quy luat dd da dugc ki^m nghiem trong mdt thdi gian dii dai Vi vay, d day cin xet de'n cac nhan td thuc su lac ddng Idn dai lugng du bao thay d6i nhu the' nao? Ben canh dd cin xem xet de'n dd dai ciia cac day sd dugc
su dung va chit lugng ciia nd
Vide xay dung cac ham hdi quy hay tuong quan phu thudc rit Idn vao dang
ham dugc su dung Vide chgn dang ham khdng chi cin hi^u bie't vi cac quy luat
kinh te' ma cdn cin cd kinh nghiem nghien cQu va thuc tiin Vin d^ nay lien quan de'n viec lua chgn cac dang ham du bao theo cac lieu chuin thdng ke da dugc nghien cQu cung nhu phu thudc vao cac nhan td khac cdn chua dugc xet trong md hinh
2.3.2 Mo hinh md phong
Md hinh md phdng cd nhiing net gin vdi phuong phap ngoai suy Sau khi
md la mdt ddi tugng qua mdl he phuong trinh, se lien hanh md phdng tim cac
dac trung ciia ddi tugng dd vdi cac diin kidn mdi nhd he phuong trinh da dugc
xay dung d^ md ta nd[31 Qua irinh irdn day phai qua mdl sd budc: bing cac phuong phap udc lugng thdng ke, tu cac day sd ciia cac dai lugng cin du bao va cac dai lugng cd lien quan vdi nd trong mdt he thdng dugc xel(chang han nhu he
thdng kinh te), ta xay dung mdl he cac phuong trinh md la md'i quan he giQa cac
dai lugng nay Ben canh cac phuong trinh dugc udc lugng tu cac day sd qua khu, cin bd sung mdl sd phuong trinh md la cac quan he giQa cac dai lugng dugc xet
do cac quy luat kinh le, cac dieu kien dat ra ciia thuc tien va su binh thanh len cac sd lieu quy dinh Chang ban, ne'u trong md hinh cd bao gdm cac dai luong: T6ng khd'i luong hang hoa van lai (x) va khd'i lugng bang hoa dugc van lai theo cac loai hinh phuong lien(xl-dudng sit, x2-dudng bd ), thi long khdi lugng hang hoa van chuyen theo tat ca cac loai hinh phuong tien khac nhau phai bing
Trang 36O^ TAI NCKH CAP OHQGHN
t6ng khdi lugng hang hoa van chuyen Phuong trinh sau day cin phai dua vao trong md hinh:
x = xl+x2+ +xn (1)
va ggi la phuang trinh dinh nghia Cac quan he nay cd th^ bi^u thi cac
phuong trinh dinh nghia hay cac diin kien ciia bai loan De'n lugt minh, mdi dai
lugng x l , x2,.-.,xn lai dugc xac dinh tQ mdt phuong trinh tucmg quan nao dd Vf
du, khdi lugng van tai dudng bd x2 la mdt ham phu thudc vao khd'i lugng san
xuit va tieu thu mdt sd' mat hang chinh ml, m2, , ml va vao GDP:
x2= f(nil,ni2, -,mt,GDP) (2)
Chinh nhd cd cac jrfiuong trinh nay[ loai (1) va loai (2)] cho phep md hinh
md la dugc quan he ciu tnic ciia cac dd'i tugng kinh te' va cac kich ban du kie'n
cd th^ xiy ra Sau khi ki^m tra su phu hgp ciia he phuong trinh vdi cac sd lieu qua khQ va danh gia dd sai sd' tin cay ciia he thd'ng md hinh, nd cd ih^ dugc su dung de du bao Bing each chgn mdl sd cac bien ngoai sinh trong sd cac bien tham gia vao he phuong trinh (chang ban nhu ml,m2, ,mt va GDP) , cho cac
bie'n nay nhQng gia tri xac dinh trong tuong lai(xem nhu nhQng diin kien dugc
xac dinh theo mdi kich ban) va tie'n hanh md phdng trdn md hinh, la dugc day cac gia tri ciia cac bie'n cdn lai (x, xl, x2, , xn) trong khoang thdi gian cin du bao, trong dd cd gia tri ciia cac dai lugng cin du bao
NhQng md hinh loai nay cho phep du bao theo cac tinh hudng, ngQ canh cac kich ban - khac nhau, ma nhQng tinh hudng nay cd the chua he xay ra trong qua khQ, nhung hoan loan cd ih^ cd trong luong lai V^ ihiic chit, day cung la mdt loai md hinh ngoai suy nhung la ngoai suy ciia ca he thdng: xem xet su thay d6i ciia trang thai mdt he thdng trong cac dieu kidn nhit dinh ciia tuong lai Ro rang cac boat ddng van lai cung la mdl bd phan cua he thd'ng kinh te' Vi vay, md hinh loai nay thudng cho cac ket qua id't hon, nhung cac du bao vdi md hinh md phdng se cdn dung chung nao ciu tnic va co che van hanh ciia be thdng dugc xet cdn chua ihay ddi nhidu Mat khac, vide xay dung cac md hinh loai nay cin
-cd cac day sd dQ dai Ngudi xay dung md binh ddi phai -cd ky nang va nhieu kinh n<>hiem, cd nhQng hieu biet nhit dinh ve he thdng Ben canh dd can cd mot phin mdm ve md hinh dii manh (chang ban nhu E\TEW[2]) de udc lugng cac phuong trinh va tien hanh cac md phdng
Trang 37Di TAI NCKH CAP OHQGHN
2.3.3 M6 hmh tuong tu
Trong cac loai md hinh, md hinh tucmg tu ciing thudng dugc sir dung d^ nghien ciiu cac dd'i tugng, dac biet cho viec du bao Md hinh tuong tu xua't phat
tut hai quan di^m: quan di^m tuong tu vi ca'u tnic (ban chat) va quan di^m tuong
tu \i van ddng theo quy luat
Theo quan di^m ca'u tnic, hai dd'i tugng cd ca'u tnic (hoac dac trung trang thai) gidng nhau thi hanh vi gidng nhau Tut hanh vi ciia mdt dd'i tugng nay cd th^ suy ra hanh vi ciia dd'i tugng khac cung ca'u tnic d mdl thdi di^m nao dd
Theo quan di^m van ddng theo quy luat, hai dd'i tugng khdng c^n bie't rd ca'u tnic, nhung cd dai lugng c^n du bao da van ddng ciing theo mdt quy luat d mdt giai doan nha'l dinh nao dd trong qua khii thi nd cdn van ddng tuong tu nhau trong giai doan tie'p theo La'y gia tri dai lugng du bao da dat dugc d giai doan sau ciia mdt dd'i tugng lam du bao cho dd'i tugng kia
Tren thuc te', cd thi ap dung ca hai quan diem d tren de tie'n hanh cac du bao vi van lai Cd th^ xem xet ca'u tnic n^n kinh te' ciia mdt niioc d mdt thdi
di^m qua khii nao dd gid'ng nhu ciia nude ta d thdi di^m trong tuong lai thi cd th^ la'y cac chi lieu tuong ling ciia nd(hoac mdt chi lieu dan xua't tii dd tinh ra chi lieu cdn du bao) d thdi di^m dd lam du bao ciia ta trong tuong lai Mdt vi du
di^n hinh la, khi du bao vi tidu thu mdt loai san ph^m nao dd, chang han nhu xi
mang, cac chuydn gia thudng la'y miic lieu thu xi mang binh quan dau ngudi d
nhirng nude cd cimg miic thu nhap binh quan theo din ngudi nhu ciia nude la d
thdi di^m tuong lai va nhan vdi dan sd de dugc con sd du bao tieu thu xi mang
Ndi chung, md hinh loai nay thudng diing de du bao cac dai lugng ma d thdi di^m tuong lai khd xac dinh dugc d^y dii cac nhan td cd anh huomg true tiep de'n dai lugng c ^ du bao Do ihie'u thdng tin nhu vay nen phai dua vao su 'tuong tu'(v^ ca'u tnic, hay quy luat trong qua khii) giiia nd va ddi lugng khac
de bd sung thdng tin lam du bao
2.3.4 Md hinh bai loan quy hoach
Md hinh bai loan quy hoach loan hgc la mdl md hinh cua loai bai loan xac dinh theo nghia: cac nhan td dii lieu dua vao trong bai loan la nhCmg con sd da cho Trong trudng hgp nay, khdng chi cac md'i quan he ciia md hinh la cac quan
he duac du bao, ma chinh cac hang sd trong md hinh cung la nhirng sd can dugc
Trang 38O^ TAI NCKH CAP OHQGHN
du bao trudc Ddi vdi cac md hinh loai nay, vide danh gia mQc dd chinh xic ciia k^t qua la rit khd khan, vi d day da cd hai qua trinh du bao didn ra ddc lap va n6i tie'p nhau: du bao cac tham sd dua vao md hinh va xac dinh cac dai luong thdng qua chinh md hinh nay
Gia sii cin du bao cac dai lugng x,, Xj, , x^
Trudc he't cin xac dinh dugc ham muc tidu ciia md hinh
f=f(X(Xi, Xj, , x„), C(Ci,C2, c„)) (1)
Tuy thudc muc tidu va y nghia cua dd'i tugng du bao ma xay dung dang ham nay va xac dinh vec to C(Cj,C2, c^^) tuong Qng Chang ban, trong dieu kidn xac dinh khd'i lugng van tai trdn cac tuye'n (x-), thi cac c, cd ih^ chgn la chi phi van tai tren tuye'n dd, va xet trudng hgp ham f la tuye'n tinh, la cd ham muc lieu
la t6ng chi phi van tai tren til ca cac tuye'n va cd dang:
CjXj + C2 X2 + ••• + C[) XQ
va yeu ciu (muc tieu cin dat de'n) la tim phuong an van lai sao cho l6ng
chi phi nay la it nhit Ddng thdi, cin phai xac dinh cac di^u kien ban che' vi
kinh te' va ky thuat dat ra cho viec tie'n hanh van tai cac khdi lugng hang hoa trdn
cac tuye'n Thdng thudng, ddi vdi md hinh van lai nhQng diin kidn ban che sau
day dugc dat ra:
a/ Dieu kien han cheve khdi luang van tdi 0 mdi diu md'i giao thdng cd
chuydn lai, cip hang hay nhan hang:
- T6ng lugng hang trd di khdi diu mdi giao thdng phai nhd hon lugng hang cd dugc 0 tai diu md'i dd
- T6ng lugng hang trd de'n mdt diu mdi phai bing lugng bang ma diu md'i
dd cin tie'p nhan d^ lai va lugng hang cho di khdi nd Gidi ban nay
thudng CO dang mdl phuong trinh hay bat phuong trinh:
gk(xi X2, , x„^, e,,e2, e^)<= (hay >=) a^ (2)
b/ Giai han ve phuang tien van tdi hay kha nang thdng qua tren tung
tuye'n: T6ng lugng bang chuyen trd tren mdt tuyen khdng dugc vugt qua kha nano tbdne qua ciia tuyen dd Gidi han nay cd the dugc chi tiet boa theo tung
Trang 390 ^ TAI NCKH CAP OHQGHN
mat hang (hang rdi, hang cdng k6nh, ) hay loai hinh i6 chQc van tai (hang rdi, hang bao gdi, cdng-ten-no)
c/ GitJti han ve ndng luc bdc xep, chuyen tdi vd kho bdi d mdt diu md'i giao
thdng-cd th^ xem la kha nang thdng qua lugng hang boa tai diu mdi dd (cung
cd nhQng di^u kidn tugng tu nhu trudng hgp b)
Cac gidi ban loai b va c thudng cd dang bit phuong trinh:
K(^v ^29 "MX„, di,d2, -,d„) <= bk (3)
d/ Khdi luang van tdi phdi la nhiing sd khong dm :
xi >= 0 vdi mpi i (4)
Ngoai ra cd thi cd them mdl sd diin kidn gidi ban khac do yeu ciu cu the
ciia boat ddng giao thdng, van tai dat ra
He cac phuong trinh va bit phuong trinh (l)-(4) cho ta mdl md hinh phan b6 khdi lugng van tai Qng vdi mdl mang ludi giao thdng cho trudc, vdi cac di^u kidn phuong tien va trang thie't hi v^ van tai cho trudc va nhu ciu van tai tai cac diu md'i giao thdng cung bie't trudc Vdi cac dQ lieu bie't trudc nay (a,,bj,Cj,,e„dj^)
la cac du bao cd dugc cho mdt thdi ky nao dd, thi khd'i lugng van tai trdn mdi tuye'n (Xi) xac dinh tQ md hinh cho ta du bao v^ nhu ciu van tai trdn tuyen dd trong thdi di^m tuong lai Ro rang la, trong md hinh nay cd the cd nhieu kich ban tuong Qng vdi cac mang giao thdng khac nhau, vdi nhu ciu van lai d cac diu md'i giao thdng la khac nhau va vdi cac ham chi phi khac nhau dugc chgn lam muc tidu cho bai loan luong ung vdi bd cac tham sd (a^,bj,Cj,,ei,dj^)
Md hinh nay dugc su dung rat rdng rai trong viec xac dinh cac phuong an kinh le ky thuat tdi uu, dac biet la bai loan phan bo ludng bang tren mdt mang giao ihdne
Mdt trono nhuoc diem ciia bai loan nay la cin phai xac dinh kha nhieu cac tham sd (ai,bj,c^,e„db) ca ve kinh te va ky thuat, ma trong tuong lai khd danh gia duoc su thay d6i ciia nd do khdng du kien dugc he't cac nhan td tac ddng len nd Them vao dd khi giai bai loan, ket qua thu dugc la mdl phuang an cue bien (nen qua "thien lech") theo ham muc lieu dinh trudc Trong khi dd cdn nhieu dieu kien thuc lien cua bai loan vi nhiing ly do nao dd cdn chua dugc dua vao md
Trang 40O^ TAI NCKH CAP OHQGHN
hinh hoSc cdn cd sai sdt trong vide lua chgn cac tham sd (apbj,c^,e„dj Vi vay,
sau khi nhan dugc phuong an phan b6 cin ki^m tra, phan tich va diin chinh,
hoan thien md hinh, phuong an nhidu lin theo each sau:
- B 6 sung them cac di^u kidn (nd'u cd th^ dugc) vao bai loan hay sua d6i
di^u kien da cd di khic phuc su bit hgp ly ciia phuong an tdi uu nhan
dugc
- Ne'u khdng th^ di^u chinh bang vide bd sung hay thay ddi cac di^u kien
trong md hinh thi di6u chinh phuong an di khic phuc nhQng bit hgp ly
dugc phat hidn
2.3.5 Phuong phap chuyen gia va bai loan sap hang
23.5.1 Phuang phap chuyen gia
Phuong phap chuyen gia la phuong phap phdng vin, tham dd, liy y kie'n
cac nha khoa hgc , cac nha chuyen mdn, cac nha san xuit, kinh doanh cd
trinh dd cao, cd nhidu kinh nghidm trong tOng llnb vuc chuyen mdn hep dugc tie'n hanh theo mdt trinh tu nao dd V^ dai th^, trinh tu dd la nhu sau:
a/ Xac dinh muc dich, nhidm vu, ndi dung va ddi lugng cin du bao
b/ Lua chgn mdt danh dich cac chuydn gia theo muc dich, ndi dung va ydu ciu du bao Cac chuyen gia phai la cd nhQng ngudi hi^u bie't sau sic v^ dd'i tugng du bao, cd boat ddng va kinh nghiem hen quan den linh vuc nay Danh sach du bao khoang tQ 20 de'n 30 ngudi la id't hon ca Nd'u khdng dii thi cd the chgn it hon, nhung khdng ndn qua it
c/ Soan thao va cung cip cho cac chuyen gia mdt hd thd'ng cac cau hdi theo ndi dung du bao va cac thdng tin lidn quan
d/ Xu ly thd'ng kd cac ket qua tra Idi ciia chuyen gia Sau mdi budc cd the loai bdi cac chuydn gia cd cac tra Idi qua ngd nghe, thieu su hieu biet sau sic ve linh vuc nay (do viec lua chgn chuyen gia luc diu cd the chua chinh xac)
e/ Thdng lin lai cho cac chuyen gia ve ket qua xir ly cac cau hoi vdng nay, cung cip them cho cac chuyen gia cac thdng tin lien quan de'n cac van de ma cau tra loi cdn phan tan va cd the bd sung them mot sd cau hdi lam ro hon cac
CO sd ciia cac y kidn khac nhau ciia chuyen gia