Bai Giang Logistics

8/9/2019 Bai Giang Logistics

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TRNG I HC BCH KHOA H NI

KHOA KINH T V QUN L

------------------------------oOo------------------------------

BI GING MN

LOGISTICSBin son: VINH NGHIM HNG

H Ni, 2005


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http://www.ebook.edu.vn 2

CHNG 1: KHI NIM V NI DUNG CA LOGISTICS

1.1. Ngun gc v khi nim Logistics

V mt t ng, ch Logistics c ngun gc t ch Logos, c ngha l hp l.Nh vy ni dung ca Logistics bao gm vic hng dn mi ngi cch thcthc hin cc cng vic sao cho hp l nht.

Logistics c ngun gc t trong qun s, n bao gm vic gii quyt cc biton v di chuyn qun lng, b tr lc lng, thit k v b tr kho tng, qunl v kh,... sao cho ph hp nht vi tnh hnh nhm mc tiu chin thng i

phng. Nu nh trong chin tranh, chin thng ch thuc v nhng ngi csc mnh qun s th trong lch s chin tranh gn gi v bo v t quc Vit

Nam khng th nh ui c cc i qun hung hn t phng Bc haynhng k c sc mnh qun s thuc loi hng u th gii nh thc dn Phpv Hoa K. V vy c th thy vic gii cc bi ton Logistics trong qun s ctm quan trng c bit.

Trong sn xut kinh doanh, Logistics cp n vic ti thiu ha chi ph, tvic mua sm nguyn vt liu cho ti vic lp, thc hin k hoch sn xut vgiao hng. Mc tiu ca Logistics trong sn xut kinh doanh l gim thiu ccchi ph pht sinh, ng thi vn phi t c cc mc tiu m doanh nghip ra.

Tm li, Logistics c thc nh ngha nh sau (Coyle, 2003):

Logistics l qu trnh d bo nhu cu v huy ng cc ngun lc nh vn, vtt, thit b, nhn lc, cng ngh v thng tin tha mn nhanh nht nhngyu cu v sn phm, dch v ca khch hng trn cskhai thc tt nht hthng sn xut v cc mng phn phi, cung cp hin c ca doanh nghip, vichi ph hp l.

1.2. Ni dung ca Logistics.

Khi tin hnh iu tra, kho st 163 doanh nghip ti chu u nm 1997, hiphi Logistics Chu u (ELA- European Logistics Association) thng k cquan im ca cc nh qun l chu u v ni dung ca Logistics nh sau(Coyle, 2003):


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Bng 1.1: Quan im ca cc nh qun l chu u vni dung caLogistics

n v: %

STT Chc nng Chu u c Php Anh1. Kho bi 83 86 99 99

2. VC bn ngoi 82 70 92 99

3. Qun l d tr vt t 81 71 99 81

4. Phn phi 72 68 67 99

5. Vn chuyn ni b 63 63 92 89

6. Qu trnh t hng 54 52 50 627. KHH sn xut 49 46 50 61

8. Mua sm 46 37 25 51

9. Dich v khch hng 33 24 23 50

10. H thng thng tin 29 25 42 31

11. Kim tra cht lng 20 15 17 0

Nh vy c th thy rng, trong sn xut kinh doanh Logistics tp trung vovic gii quyt cc vn sau y:

1.2.1. Xc nh ngun cung cp

Xc nh ngun cung cp hay cn gi l nh ngun. Ni dung ca cng vicnh ngun bao gm vic nh gi v la chn nh cung cp tt nht.

Trong sn xut kinh doanh, doanh nghip phi mua nguyn vt liu t cc nh

cung cp, thm ch phi mua cc chi tit, linh kin lp rp sn phm. Trnth trng cng c rt nhiu nh cung cp hng ha c thp ng c yucu ca doanh nghip. Tuy nhin mi nh cung cp khc nhau li a ra ccsn phm c cht lng c th khc nhau, ng thi gi bn cng c s khc

bit. Thng thng sn phm c cht lng cao hn th c gi bn cao hn vngc li. Ngoi ra doanh nghi p cn phi cn nhc vic la chn nh cungcp no cung cp hng ha cho mnh da trn cc yu t, ch tiu khc nh:ch bo hnh, dch v hu mi hay cc phng thc chit khu gim gi.

Ni tm li, vic nh gi cc nh cung cp phi da trn mt h thng cc ch

tiu m doanh nghip a ra ch khng th ch da trn mt ch tiu duy nht.C nh cung cp c th mnh tiu chun ny nhng li km thtiu chun


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khc, v vy nh ngun sa ra phng php dng nh gi cc nh cungcp da trn cc tiu chun khc nhau .

1.2.2. Lp k hoch sn xut ti u

Trc khi tin hnh sn xut doanh nghip thng phi d bo nhu cu ca thtrng i vi sn phm do mnh sn xut ra.

Gi s doanh nghip X d bo nhu cu v sn phm ca mnh trong 3 thngcui nm (10, 11, 12) nh sau:

Bng 1.2: Dbo nhu cu sn phm ca cng ty X

t 10 11 12

Dt 2 3 4

Nh vy nu chu k sn phm nh hn mt thng th chng ta cng c rtnhiu k hoch sn xut c thp ng c nhu cu trn. V d:

Bng 1.3: Cc khoch sn xutp ng nhu cu c dbo

t 10 11 12

Dt 2 3 4

KH1 2 3 4

KH2 2 7 0

KH3 9 0 0

bng trn ta c th thy c t nht 3 k hoch sn xut c thp ng cnhu cu v sn phm bng 1.2. k hoch th nht ngi ta sn xut mithng mt lng ng bng nhu cu ca thng . K hoch th 2 ngi ta snxut 2 sn phm thng 10; thng 11 sn xut 7 sn phm bn thng 11,

12; thng 12 khng sn xut. K hoch th 3 l sn xut c 9 sn phm thng10 cung cp cc thng 10, 11, v 13; thng 11, 12 khng sn xut.

Trong thc t cc k hoch sn xut khc nhau yu cu nhng chi ph khcnhau, v ngi lm cng tc Logistics phi xc nh c k hoch sn xutno cho chi ph t nht. iu cn c mt thut ton xc nh.

1.2.3. D tr v bo qun nguyn vt liu, hng ha

Trong sn xut, d trng vai tr v cng quan trng. N nhm hn ch vicgin on sn xut v cung ng sn phm, p ng nhu cu v sn phm, dchv mt cch nhanh nht.


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Tuy nhin ngi lm cng tc Logistics phi xc nh c chi ph cho vic dtr, bo qun bao nhiu l ti u. N lin quan ti vic xc nh loi kho hngv t chc cc t nhp hng.

Nu trong nm vic nhp hng c chia lm nhiu ln th s gim c chiph d tr, chi ph vn nhng iu cng s lm pht sinh thm chi ph vnti. Ngc li nu s ln nhp hng trong nm l t th s gim c ch ph vnti nhng s lm tng chi ph lu kho, ng thi chi ph vn cng tng thm.

Ngoi ra s lng hng ha cn mua trong mt ln t hng cn ph thuc vokh nng ti chnh ca doanh nghip, chnh sch chit khu gim gi ca ngi

bn v dung lng ca kho hng.

V vy vic xc nh s ln t hng v s lng t hng ti u trong nm lmt iu ht sc cn thit v i hi phi c cn c khoa hc.

1.2.4. T chc h thng phn phi

T chc h thng phn phi lin quan n vic t chc di chuyn phng tin,phn b ngun hng ti cc th trng, xc nh s lng kho hng ti u.

Vic di chuyn phng tin v hng ha t kho n cc khch hng c th thchin trn nhiu tuyn ng khc nhau. Chi ph trn mi tuyn ng cng cth khc nhau do ph thuc vo qung ng di chuyn, ph cu ng, thmch l cc khon tiu cc ph nu c. V vy mt trong cc chc nng caLogistics l phi ch ra vic phn b hng ha ti u cho cc th trng v conng vn chuyn c chi ph thp nht.

Ngoi ra ngi lm Logistics cn phi xc nh c s lng kho hng ti utrong iu kin c th ca doanh nghi p. Nu s lng kho hng ln s lmgim chi ph vn chuyn t cc kho n cc khch hng, tuy nhin n lm phtsinh thm chi ph vn chuyn t ni sn xut n cc kho v pht sinh thm ccchi ph d tr cng nh chi ph qun l kho.

1.2.5. B tr kho hngB tr kho hng bao gm cc cskhoa hc trong vic thit k mt nh kho,sp xp hng ha trong kho cng nh vic di chuyn hng trong nh kho .

1.2.6. Bao gi

Ni dung ny bao gm vic thit k cc bao b sao cho hp l d dng trongvic vn chuyn cng nh sp xp ti u trn cc xe nng hng.

Ngoi ra ni dung ny cn cp ti vn nhn dng, qun l hng ha trongkho sao thun tin v nhanh chng.


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1.2.7. Qun l mng cung cp v phn phi hng ha

Ni dung ny bao gm vic qun l ton b h thng phn phi c thitlp sao cho chng hot ng thc s c hiu qu v khoa hc.

1.3. So snh mt s ni dung ca Logistics vi Marketing

Chng ta u bit mt trong nhng ni dung ca Marketing l Phn phi hngha (Place) v Logistics cng gii quyt vn phn phi trong ni dung camnh. Nh vy liu c s chng cho chc nng gia Logistics v Marketinghay khng?

Cu tr li l KHNG.

Phn phi trong Marketing cp ti vic xc nh loi knh bn hng, cc loiv s lng cc trung gian phn phi hng ha tng ng (i l, nh bn

bun, v nh bn l). Phn phi trong Marketing khng cp ti v tr c thv cn thit ca cc trung gian phn phi hng ha trong khu vc a l xcnh. ng thi n cng khng quan tm ti vic t chc vn chuyn hng hanh th no, chi ph l bao nhiu; n ch quan tm ti vic hng ha c cchuyn n ng a im v ng thi hn hay khng.

Nh gii thiu mc 1.2.4, phn phi trong Logistics thc hin cng vic dichuyn phng tin v hng ha nh th no ti th trng v cc khch hngsao cho ng vi cc yu cu t ra vi chi ph hp l nht.

Nh vy c th hiu phn phi trong Marketing l ngi t ra vn , t rayu cu v phn phi trong Logistics phi c nhim vp ng cc vn vcc yu cu c t ra sao cho chi ph thc hin l ti u nht.

Tng t nh vy l vn bao gi sn phm. Trong vic bao gi, Marketingquan tm ti mu sc, hnh dng ca bao b sao cho bt mt v c th qung bc thng hiu ca nh sn xut hay nh phn phi sn phm . Marketing

quan tm ti mu sc c in bn ngoi bao b l mu g, cc hnh v, k hiuch vit cn phi in v tr no l ph hp. Logistics th quan tm ti kch cv vt liu ca bao b. i vi Logistics, mu sc in trn bao b l mu g cngc, min l thng hng (bao b) c th xp c mt cch ti u trongnh kho, trn cc phng tin vn ti hay trn cc tm nng hng, ng thi vtliu ch to bao b phi ph hp vi iu kin bo qun sn phm v tnh chtca sn phm.

Nh vy ni mt cch ngn gn, Marketing quan tm ti cc tnh cht c tnhthm mv hnh thc th hin trn bao b sn phm cn Logistics quan tm ti

cc tnh cht vt l ca bao b .


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CU HI N TP

1. Trnh by khi nim, ni dung, v mc ch ca Logistics trong sn xutkinh doanh.

2. Hy so snh mt s ni dung ca Logistics vi Marketing. Ti saochng li c s khc nhau ?

3. Cng vic phn phi hng ha v thit k bao b sn phm trongLogistics quan trng hn hay trong Marketing quan trng hn? Ti sao?


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CHNG 2: XC NH NH CUNG CP (NH NGUN)

2.1. Doanh nghip nn t hng gia cng hay tsn xut?

Trong sn xut kinh doanh, doanh nghi p c th t mnh tim kim v khaithc nguyn vt liu cng nh t mnh sn xut ton b linh kin, chi tit chosn phm ca mnh. Doanh nghip t tm kim nguyn vt liu v sn xut ccchi tit, linh kin cho sn phm ca mnh trong cc trng hp sau y:

- Doanh nghi p mun khng nh kh nng ca mnh vi khch hng.Trong nhng trng hp nh vy nhiu khi chi ph sn xut cn ln hnso vi vic mua t cc doanh nghip khc nhng nh sn xut vn cthc hin. Mc tiu ca nh sn xut lc ny l khng nh vi khchhng kh nng sn xut, kh nng cng ngh ca mnh, trong con mtca khch hng doanh nghi p mnh khng h thua km cc doanhnghip khc. Hoc cng c th v l do khc nh chin lc ca doanhnghip.

- Doanh nghip mun gi b mt v cng ngh. V l do bo m b mtv cng ngh, doanh nghip s tin hnh t sn xut chi tit, linh kincho sn phm. Nu thu gia cng th doanh nghi p phi chuyn giaocng ngh sn xut v cc ti liu c lin quan cho ngi gia cng. iu l v cng nguy him cho doanh nghip nu nh cng ngh l tisn ch yu ca mnh v nhiu doanh nghip khc mun c c n.

- Doanh nghip mun kim sot v gi mc cht lng cao cho sn phm.Nhiu khi doanh nghi p mun kim sot cht lng v m bo mccht lng cao cho sn phm th phi t sn xut, v t sn xut doanhnghip mi kim sat c ton b qu trnh gia cng, ch bin, t vicmua nguyn vt liu cho ti vic thc hin sn xut v ng gi sn

phm.- Mt l do na l doanh nghip mun m bo an ton cho khu cung

cp. V t mnh sn xut doanh nghip mi c thm bo chc chnkh nng c nguyn vt liu, vt t v p ng ng thi gian yucu, trnh c s gin on sn xut.

Tuy nhin do s phn cng lao ng x hi, do nhu cu v chuyn mn ha mthng thng nguyn vt liu, chi tit hay linh kin sn phm phi c nhpt cc doanh nghi p khc. Thm ch trong thc t c doanh nghi p ch thchin cng vic lp rp (cng vic lp rp thm ch cng c th b qua) v dnnhn sn phm mang tn mnh phn phi ra th trng.

Vic mua nguyn vt liu, mt phn sn phm hoc ton b sn phm t ccdoanh nghip khc cn c th pht sinh do vic bin i ti trng hng ha cncung cp (nhu cu pht sinh t ngt), cc l do v ti chnh (mua ca ngikhc r hn so vi t mnh sn xut, hoc khng tin xy dng b phn

sn xut), hoc cc l do k thut khc (khng nng lc, trnh snxut).


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V d khi cc con n trng cc bc cha m thng dn: n lp con chcchi vi cc bn ngoan, khng nn chi vi cc bn h.

Nh vy rt kh cho a tr v n khng th bit c nh th no l bnngoan. Nhng nu cc bc cha m ni c th hn: n lp con chc chivi cc bn bit vng li c gio, qun o sch s, khng nghch bn, khngtranh ginh chi, khng nh nhau,... th s d dng cho a tr hn rtnhiu trong vic chn bn chi cng. Thc t cho thy, nu ch bo cng chitit th a tr cng d thc hin (tuy nhin nhiu qu cha chc tr con nhc).

V cng ging nhbc 2, bc ny ngi nh gi cng cn xc nhtrng s cho tng ch tiu nh.

2.2.4. Bc 4: Xc nh thang im cho mi ch tiu con.

V l do mc quan trng ca cc ch tiu khc nhau l khc nhau, v vythang im dng nh gi cc nh cung cp theo tng ch tiu cng khngcn phi nh nhau.

Vic nh gi hc lc ca hc sinh trong cc trng ph thng ngi ta sdng thang im 10, im l l . Nhng khi chm im thi hc sinh gii cptnh hay cp quc gia phi s dng ti thang im 20, im l c khi xung ti, v lc ny ngi ta yu cu chnh xc phi ln hn th mi c thnhgi c chnh xc. V k thi quc t ngi ta phi s dng thang im lnti 40.

V vy nu trong h thng cc ch tiu nh gi nh cung cp, nu ch tiuno cng quan trng th thang im cho n cng phi ln.

2.2.5. Bc 5: Sloi da trn cc tiu chun d nhn bit.

Sau khi xy dng xong h thng cc ch tiu nh gi, ngi ta tin hnhnh gi cc nh cung cp, tuy nhin c th s xut hin mt phi nh cung cp

phm quy ngay tu, v vic pht hin ra cc nh cung cp phm quy l ht sc d dng. V vy trc khi tin hnh nh gi ngi ta thng thchin qua bc s loi. Trong vic tuyn dng nhn vin cc doanh nghip,

bc ny chnh l bc kim tra v loi ng c vin trn h s.

2.2.6. Bc 6: Cho im cho cc nh cung cp theo tng ch tiu.

Sau khi thc hin qua bc s loi, tt c cc nh cung cp qua cvng 1 sc nh gi v chm im da trn cc ch tiu, cc thang imm ngi nh gi xy dng c cc bc trc. Trong qu trnh nh

gi, mt s cc ch tiu nh lng c thc nh gi mt cch kh chnh


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xc, ngc li mt s cc ch tiu c tnh nh tnh th li ph thuc nhiu voch quan ca ngi nh gi.

2.2.7. Bc 7: Tnh im tng cng v la chn.

y l bc cui cng trong vic nh gi v la chn nh cung cp.

Ngi ta tnh im tng cng bng cch ly im ca tng ch tiu nhn vitrng s tng ng ri cng li. Kt qu ra bao nhiu s l sim cui cngca nh cung cp .

Cui cng ngi ta chn nh cung cp l ngi c tng im cao nht.

2.3. Phng php AHP trong vic nh gi v la chn nh cung cp.

Trong mc 2.2 trnh by cc bc trong vic nh gi v la chn nh cung cpni chung, p dng cho trng hp tng qut.

mc ny chng ti xin trnh by mt phng php nh gi c th, c tn gil phng php AHP (Vu Dinh Nghiem Hung, 2002). Phng php AHP cs dng trong trng hp nh gi vi s lng nh cc nh cung cp v vimt s t cc ch tiu (thng l nh hn 10).

cho d hiu, chng ti xin trnh by phng php AHP vi v di km sauy:

V d: C mt doanh nghip ng trc vic la chn 1 trong 5 d n: A, B, C,D, E u t. Vic nh gi v la chn d n cn c trn 5 ch tiu: (C1)Vn u t ban u, (C2) Thi gian thc hin d n, (C3) Thi gian hon vn,(C4) Tin li trung bnh hng nm, v (C5) Li sut ca d n.

Vic nh gi cc da n da trn cc tiu chun nh nu c m t tronghnh 2.1.


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Hnh 2.1:nh gi 5 dn da trn 5 tiu chun

2.3.1. Bc 1: xc nh trng s cho cc tiu chun.

xc nh trng s cho cc tiu chun ra, ngi ta lp ra mt ma trnvung cp n (vi n l s lng cc ch tiu ra, trong v d ny n=5).

Bng 2.1: So snh cc chtiu

C1 C2 C3 C4 C5

C1

C2

C3

C4

C5

Sau ngi ta tin hnh so snh cc ch tiu theo tng cp, trong v d ny c5 ch tiu, nh vy ngi nh gi phi tin hnh so snh 15 cp ch tiu.

V d nu ngi nh gi cho rng ch tiu C1 quan trng bng ch tiu C2 thti (1,2) ngi ta in s 1, nu ngi nh gi cho rng ch tiu C1 quan

trng ch bng 1/3 ch tiu C3 th ti (1,3) ngi ta in vo s 1/3 . V cnh th cho ti cp th 15. cng l l do ti sao cc nm trn ng cho

MC TIU: Chn dnu ttt nht

C1 C2 C3 C4 C5

D.A.A

D.A. B

D.A. C

D.A. D

D.A. E

D.A.A

D.A. B

D.A. C

D.A. D

D.A. E

D.A.A

D.A. B

D.A. C

D.A. D

D.A. E

D.A.A

D.A. B

D.A. C

D.A. D

D.A. E

D.A.A

D.A. B

D.A. C

D.A. D

D.A. E


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ca ma trn c gi tr l 1. Cc i lng c k hiu l cc aij. Cc aijhoc nghch o ca chng phi l cc s nguyn t 1 n 9.

Bng 2.2: So snh cc chtiu

C1 C2 C3 C4 C5

C1 1 1 1/3 1/7 1/5

C2 1 1 1 1/5 1/5

C3 3 1 1 1/3 1/3

C4 7 5 3 1 1

C5 5 5 3 1 1

V mt iu lu na, l cc thuc na di ca ma trn c gi tr bnggi tr nghch o ca cc tng ng na trn, i xng qua ng choca ma trn.

2.3.2. Bc 2: tnh ton mc quan trng (trng s) cho cc ch tiu.

Sau khi thnh lp xong ma trn, ngi nh gi s tin hnh tnh ton cc trngs ca cc ch tiu thng qua cc i lng sau y:

( ) ( ) ( )[ ] iaaaw mimiii = ,...1

21 (2.1)

i

w

wnw

m

i

i

ii =

=

,

1

(2.2)

Nh vy t bng 2.2 ngi tnh ra c:

nw1= 0.059

nw2= 0.079nw3= 0.121nw4= 0.383nw5= 0.358

y chnh l trng s ca cc ch tiu tng ng C1, C2, C3, C4, v C5.Tuy nhin n y ta phi lu mt iu l:

Khi so snh C1 vi C2, ngi ta cho rng C1 quan trng bng C2.Khi so snh C1 vi C3, ngi ta cho rng C1 quan trng bng 1/3 so vi C3.

Nh vy nu theo tnh cht bc cu th C2 phi quan trng ch bng 1/3 so viC3.


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Nhng thy rng khi so snh C2 vi C3, ngi ta cho rng C2 quan trngnhC3.

Trong l thuyt ca mnh, ng Saaty, tc gi ca AHP, a ra khi nim xungkhc. Nu t s xung khc t mc


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Gi s sau khi tnh ton ngi ta c c cc trng s v im ca cc d nnh sau:

Hnh 2.2: Trng sca cc tiu chun v im ca cc dn

2.3.4. Bc 4: Tnh im cho cc d n v la chn.

y l bc cui cng trong qu trnh nh gi v la chn. Ngi ta tnh im

bng cch ly ly tng ca im ca d n theo tng ch tiu nhn vi trng sca cc ch tiu tng ng.

V dim ca d n A c tnh nh sau:

D.A A = 0.1460.059+0.20.079+0.3080.121+0.4780.383+0.3520.358= 0.371

C nh vy cui cng ta c bng im nh sau:

Bng 2.3:im tng hp ca cc dn

STT Dn im Xp hng1 A 0.371 12 B 0.218 23 C 0.141 44 D 0.177 35 E 0.093 5

Cui cng ta thy d n A c im cao nht v sc la chn thc hin.

MC TIU: Chn dn u ttt nht

C1 C2 C3 C4 C5

D.A A

D.A B

D.A C

D.A D

D.A E

D.A A

D.A B

D.A C

D.A D

D.A E

D.A A

D.A B

D.A C

D.A D

D.A E

D.A A

D.A B

D.A C

D.A D

D.A E

D.A A

D.A B

D.A C

D.A D

D.A E

0.059 0.079 0.121 0.383 0.358

0.146

0.127

0.2210.253

0.253

0.2

0.2

0.2

0.2

0.2

0.308

0.248

0.142

0.188

0.114

0.478

0.255

0.0970.148

0.022

0.352

0.186

0.162

0.186

0.114


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Trn thc t ngi ta cung cp cho chng ta cc cng c la chn cc mctiu theo nhiu tiu chun nh th ny chng ta khi phi tnh ton mt cchth cng nh trn.

Trong h thng trgip ra quyt nh ngi ta c gii thiu mt trong cc cngc, l phn mm Exper Choice. S dng phn mm ny ngi nh gich cn a vo h thng nhn nh ca mnh khi so snh cc tiu chun v sosnh cc i tng cn nh gi theo cc tiu chun . Ni mt cch khc lngi s dng ch cn in vo cc bng nh bng 2.2 ri h thng s t tnh racc ch s CR, trng s ca cc tiu chun, im ca tng i tng theo tngtiu chun, v cui cng l i tng c la chn.

Tham kho thm ti http://www.expertchoice.com

2.4. Ngun thng tin v cc nh cung cp.

Khi nh gi v so snh cc nh cung cp, ngi ta c th tm kim thng tinv cc nh cung cp theo cc ngun sau:

- Cc ngun thng tin ni b:

y c th l nhng thng tin vit tay hoc nhng thng tin ly ra t csdliu ca doanh nghi p, cc thng tin c th thu thp c l: thi hn giaohng, t l ph phm, s ln lhn, nng lc cung cp.

- Qung co:

Khi s dng thng tin ny doanh nghip cn lu rng y l nhng thng tin c chau chut v cung cp nhng ni dung mi v nh cung cp.

- Thng tin trn bo ch

Thng tin trn cc tp ch chuyn ngnh thng cung cp thng tin v nhngtin b k thut mi, nhng ng dng mi, v nhng thnh cng mi. Tp ch

chuyn ngnh l ngun thng tin ng tin cy v trc khi c cng b baogi ngi ta cng tin hnh thm tra chnh xc, trung thc ca thng tindi gc khoa hc cng nh lut php.

- Catalogue ca nh cung cp:

Catalogue thng c thit k rt p, n cho bit nhng thng tin chi tit vsn phm cn mua nh: tnh nng tc dng, thng s k thut, gi c, thi gians dng, ch bo dng,..

- Cc nh k thut v nhn vin ca nh cung cp:


17/54


Ty theo doanh nghip m ngi ta c th tip xc c vi cc i tng nhnhn vin bn hng, cc nh k thut, cc nh qun l ca ngi cung cp tm hiu ton din v nh cung cp cng nh sn phm ca h.

- Tham quan nh cung cp:

y l mt trong nhng hnh thc tm kim thng tin ph bin bi v n ciu kin tt nht tm hiu v nng lc k thut v nng lc sn xut ca nhcung c p. Ngi ta cng c th tm hiu c cht lng ca qu trnh snxut, phng php lp chng trnh sn xut cng nh kh nng ca i ngcn b k thut bng hnh thc tm hiu ny.

- S dng cc mu sn phm th ca nh cung cp:

Cc mu th sn phm gip ngi mua c th th nghim, so snh, thm ch lphn tch kho nghim cht lng a ra kt lun trc khi c quyt nhmua hng.

- kin ca ng nghip:

Trong trng h p khng th ly c thng tin bng cc cch khc th cchny cng l mt phng php ng quan tm, ng nghip y c th l cc

bn hng, cc nh sn xut khc c bit nu h khng phi l i th cnhtranh trc tip.

- Csd liu v nh cung cp:

y l ngun ti nguyn qu gi m chng ta hoc nhng ngi khc c uctrong nhng ln tip xc trc y vi nh cung cp. Mt iu phi lu l ccthng tin ny cn c cp nht thng xuyn, c bit l thng tin v lch sgi c, mc cht lng, kh nng giao hng.

- Cc bo co kt quiu tra ca ngi th 3.

Mt s doanh nghip khng th t mnh iu tra c c nhng thng tincn thit th c th thu cc cng ty t vn hoc vn phng chuyn mn lmvic . Cc bo co kt qu nghin cu t nhng thng tin m h thu thpc ng vai tr nh mt ngun thng tin hu ch v tin cy.


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CU HI N TP

1. Ti sao phi nh gi cc nh cung cp ni ring v cc i tng nichung theo nhiu ch tiu khc nhau?

2. Hy cho bit u nhc im ca phng php AHP v phm vi p dngca n.

3. Hy cho bit mc tiu ca anh, ch trong 2 nm ti v cho bit mc u tin ca tng mc tiu (p dng phng php AHP).

4. Hy cho bit c thng tin v cc nh cung cp th ngi ta c th tmhiu bng nhng cch no?


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CHNG 3: KHO HNG V BI TON PHN B H THNG KHO

3.1. Kho hng.

3.1.1. Khi nim kho hng v vai tr ca n.

Kho hng l ni m lu gi v cha hng ha, n thc hin cc chc nng sauy:

- Tp hp hng ha vn chuyn.

Hnh 3.1: Tp hp hngvn chuyn

- Cung cp v trn hng.

Hnh 3.2: Cung cp v trn hng ha

Cc nh cung cp

Kho hng Nh my

Nh my 1SX : A v B

Nh my 2SX : C v D

Nh my 3SX: E v F

Kho hng

Khch hng 1Mua : A , C, v D

Khch hng 2Mua : B,C, v E

Khch hng 3Mua : F, E, v A


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- Trung chuyn hng trong ngy.- Lm dch v.- Ngn nga ri ro.- iu ha sn xut

3.1.2. Cc hot ng cbn ca kho hng.

Cc hot ng trong kho hng c m t v sp xp nh trong hnh di y:

Hnh 3.3: Cc hotng cbn ca kho hng

3.1.3. Cch b tr v thit k nh kho.

Cc b tr v thit k nh kho cn tun th cc nguyn tc sau:

- S dng nh kho mt tng

- Di chuyn hng ha trong kho theo ng thng

Ly hng

Tm v tr ct giLy sn phmDi chuyn sn phmCp nht thng tin

Ct gi

Chun b vn chuyn

ng giDn nhnTin hnh vn chuyn

Ly n hng

Kim tra thng tinLy hng

Vn chuyn

Xe n theo lchCht hng ln xeGiy vn chuynCp nht thng tin

Nhn hng

Tip nhn xe theo lchDhngKim tra hng hc

HNG VO

HNG RA


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Hnh 3.4: Di chuyn hng ha theo ng thng

- S dng thit b bc xp ph hp

- Ti thiu ng i trong kho

Hnh 3.5: Ti tiu ha ngi trong kho

- S dng ti a cao ca nh kho

- S dng hiu qu mt bng kho

Nhn Chuyn Nhn Chuyn

Nhn

Chuyn

Nhn

Chuyn

NN: KHNG NN:

NN: KHNG NN:


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Hnh 3.6: ln ca nh kho c tnh bng thtch ca n

3.1.4. Thc o nng sut v hiu qu ca mt nh kho.

Nng sut v hiu qu ca mt nh kho c th hin qua cc ch tiu sau y:

- Khi lng hay n v hng di chuyn trong ngy- S lng nhn vin cn di chuyn mt kg hng- Khi lng xp dtrong mt gi- Khi lng hng ly ra t kho trong mt gi- Khi lng hng cht ln xe trong mt gi- T ln hng c thc hin ng

- T s nng sut = Khi lng x l/ngy chia cho gi cng laong/ngy

- Khi lng vt liu di chuyn trong h thng trong mt khong thigian nht nh

3.1.5. Quyt nh lin quan ti s shu kho hng.

Mc ny nhm tr li cu hi: khi s dng nh kho th doanh nghip nn sdng kho i thu hay kho do doanh nghip t xy.

Nh gii thiu ti chng 1, nu cn c trn mc tiu ca Logistics l tithiu ha chi ph th c th tr li cu hi trn trong hnh v sau y:

Hy ch c chiu caoca kho

ch khng phi ch

chiu su v chiu rng

Cho d khng dng th bn vn c phi trtin cho ch ny lc xy (hoc thu) kho


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Hnh 3.7: Chi ph lu kho trong 2 trng hp: thu v txy

Nh vy c th thy, nu lng hng lu kho thng xuyn lun ln hn mcQ* th doanh nghip nn t xy kho v ngc li th nn i thu.

Tuy nhin trong thc t vic thu hay t xy ca doanh nghip cn ph thucvo nhiu yu t khc na, c th:

- Sn nh v nhu cu

- Mt ca th trng- S cn thit v an ninh v kim sot cht lng- S cn thit phi phc v khch hng- S cn thit cho cc mc ch khc ca doanh nghip

Snh hng ca cc yu t ny ti quyt nh thu hay xy kho c trnhby trong bng sau y:

Bng 3.1: Cc c trng ca cng ty nh hng ti quytnh vshukho

STT c trng Kho txy Kho i thu1 Khi lng Cao Thp2 Nhu cu n nh Dao ng3 Mt th trng Cao Thp4 Kim sot v vt l Cn thit Khng cn5 Dch v khch hng Cao Thp6 Yu cu v an ninh Cao Thp7 S dng cho nhiu mc ch Cn Khng cn

Nu s dng kho thu th cn lu cc c im sau y c thnh hng tichi ph thu:

Chi ph khi thu kho

Chi ph ca kho t xy

Chiph

Lng hng lu khoQ*


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- Gi tr mt hng- Tnh d hng ca hng ha- Kh nng gy thit hi n cc hng ha khc- Khi lng v su n ca hng gi- T khi ca hng ha- Mc dch v yu cu

3.1.6.Nhn dng hng ha trong kho

Trong thc t mt kho hng d ln hay nh cng u cha nhiu loi hng hakhc nhau, thm ch cng mt loi hng ha cng c thc chia thnh nhiuloi nh hn, ph thuc vo cht lng, hnh thc, hoc mt vi tnh cht khc.

Nh vy d dng cho vic gi tn, phn loi v sp xp hng ha trong khongi ta t cho mi hng ha mt tn gi. Tn gi ny phi tha mn iukin ng nht v mt cu trc, phn bit cc hng ha khc nhau mt cch ddng. Vic gn cho mi hng ha trong kho mt tn gi nh vy ngi ta gi lm ha hng ha.

Theo Nguyn Vn Ba (2003) v Grard Chevalier, Nguyn Vn Nghin (1998),vic m ha hng ha c th thc hin theo mt trong ba phng php sau y:m ha tun t, m ha phn tch, hoc m ha hn hp.

M ha phn tch tc l m ha cc i tng da trn mt vi tnh cht cai tng , ni mt cch khc l ngi ta c th phn tch b m bit mtvi tnh cht ca i tng c m ha.

V d nh qun o bn siu thc m ha: XL, L, M, v S. l m theokch cca chic o, tng ng vi cc c: siu rng, rng, trung bnh, v nh.Hoc nu ai i my bay th u bit tn gi cc sn bay c m ha theo kiuny. V d:

Bng 3.2: M ha tn gi ca mt ssn bay quc ttrn thgii

STT M Tn sn bay1 HAN Ni Bi (Vit Nam)2 SGN Tn Sn Nht (Vit Nam)3 BKK Don Muang (Bng Cc Thi Lan)4 SIN Singapore5 LAX Los Angeles (Hoa K)6 YAN Yangon (Lin bang Myanmar)7 LON London (Anh)8 SYD Sydney (c)

9 TYO Tokyo (Nht Bn)10 MOW Moscow (Nga)


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M ha tun tl kiu m ha khng ph thuc vo c im ca i tngc m ha m ch ph thuc v thiim c m ha. i tng c mha trc s nhn m c s th t nh, i tng c m ha sau s nhnc m c s th t ln hn.

B m tun t th chng ta thng c gp mi khi phi ly phiu (hoc cngi l ly s) khi vo khm bnh, khi xp hng mua v my bay, v tu hockhi i c phc v ti cc ngn hng. R rng l vic ly c phiu c sth t nh (sc phc v trc nhng ngi ly phiu c s th t ln hn)l ph thuc vo thi im chng ta ly phiu ti cc a im , khng phthuc vo bnh tnh (trong bnh vin) hay gii tnh, tui tc, a v cng tc(trong quy v, ngn hng).

Kiu m ha th 3 l kiu m ha hn hp, y l kiu kt hp gia m hatun t v m ha phn tch. Trong m hn hp gm c 2 phn, phn tun t v

phn phn tch. Kiu m ha ny chng ta thng gp hn c. V d nh tuynsinh vo i hc mt th sinh c thc gn m (chnh l s bo danh) nhsau: BKA-00001. Phn BKA cho bit th sinh ny thi khi A vo trng HBch Khoa H Ni, cn 00001 l s th t ca th sinh trong s tt c ccth sinh thi vo trng ny.

B m ny chng ta cn bt gp hng ngy mi khi tham gia giao thng. Cck hiu trn bin sng k xe chnh l m hn hp. V d: 29 K4-4380. 29cho ta bit chic xe ny ng k ti H Ni, cn K4-4380 chnh l phn tunt ca b m .


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Bng 3.3: Sng k xe ca cc tnh thnh ti Vit Nam

STT a phng Shiu STT a phng Shiu

1 Cao Bng 11 33 Tin Giang 63

2 Lng Sn 12 34 Vnh Long 64

3 Bc Giang 13, 98 35 Cn Th 65

4 Qung Ninh 14 36 ng Thp 66

5 Hi Phng 15, 16 37 An Giang 67

6 Thi Bnh 17 38 Kin Giang 68

7 Nam nh 18 39 C Mau 69

8 Ph Th 19 40 Ty Ninh 70

9 Thi Nguyn 20 41 Bn Tre 71

10 Yn Bi 21 42 B Ra - Vng Tu 72

11 Tuyn Quang 22 43 Qung Bnh 73

12 H Giang 23 44 Qung Tr 74

13 Lo Cai 24 45 Tha Thin - Hu 75

14 Lai Chu 25 46 Qung Ngi 76

15 Sn La 26 47 Bnh nh 77

16 in Bin 27 48 Ph Yn 7817 Ha Bnh 28 49 Khnh Ha 79

18 H Ni 29, 30, 31, 32 50Cc CSGT B - S (BCng An)

80

19 H Ty 33 51 Gia Lai 81

20 Hi Dng 34 52 Kon Tum 82

21 Ninh Bnh 35 53 Sc Trng 83

22 Thanh Ha 36 54 Tr Vinh 84

23 Ngh An 37 55 Ninh Thun 85

24 H Tnh 3856

Bnh Thun 8625 Nng 43 57 Vnh Phc 88

26 c Lc 47 58 Hng Yn 89

27 c Nng 48 59 H Nam 90

28 Lm ng 49 60 Qung Nam 92

29 H Ch Minh 50, 51, ... 58, 59 61 Bnh Phc 93

30 ng Nai 60 62 Bc Liu 94

31 Bnh Dng 61 63 Hu Giang 95

32 Long An 62 64 Bc Kn 9765 Bc Ninh 99

3.1.7. Kt cu ca h thng kho.Cng ging nh kt cu ca h thng phn phi trong Marketing, h thng khotrong Logistics c th c kt cu nh sau:


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Hnh 3.8: Kt cu ca hthng kho

3.2. Bi ton phn b h thng kho.

Nh my Khch hng

Nh my Kho trung tm Khch hng

Cc kho a phng Nh my Khch hng

Kho trung tm

Cc kho a phng

Nh my Khch hng


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Nh mc 3.1.7 trnh by, doanh nghip c th la chn h thng khng ckho hng, s dng 1 kho trung tm phn phi cho khch hng, hoc hthng nhiu kho hng.

Logistics quan tm ti vn l v tr ca cc kho hng ny nn nm utrong khu vc a l m doanh nghip quan tm.

Mi ngi u bit l chi ph vn chuyn hng ha t nh my n cc kho hayt kho n cc khch hng ph thuc vo 2 yu t: khi lng chuyn chvqung ng si. Trong trng hp doanh nghip s dng 1 kho trung tm phn phi hng ha th v tr ca kho ny c xc nh nh sau:

Ngi ta a tt c cc a im cn nhn hng ln cng mt h trc ta , lcny v tr ca cc a im v kho hng sc xc nh bi tung v honh ca chng. V ta ca kho hng c xc nh bi cng thc sau y:

=

=

=n

i

i

n

i

ii

O

Q

xQ

x

1

1 (3.1)

=

=

=n

i

i

n

i

ii

O

Q

yQ

y

1

1 (3.2)

Vi:

n: sa im cn nhn hngQi: lng hng m a im thi cn nhn

xi, yi: tung v honh ca a im thixO, yO: tung v honh ca kho hng

Phng php xc nh nh trn gi l phng php trng tm. im hn chca phng php ny l n coi khong cch gia cc a im trn h trcta l chiu di on thng ni cc im , iu ny l khng thc t bi vchiu di qung ng gia 2 a im khng phi c tnh theo ng chim

bay, mt khc phng php ny khng tnh n trng hp a im c xcnh c th s khng xy (hoc thu) c kho. Ngoi ra gi c trong vic thu(hoc xy) kho ti a im xc nh c cng khng thy cp n trongni dung ca phng php.

Trng hp doanh nghip mun s dng nhiu hn mt kho hng th s lngkho hng ti u c xc nh nh sau:


29/54


- Chn ra na im bt k v gi thit mi a im s xy mt khohng

- Xc nh chi ph trong trng hp s dng n kho (CFn)- Quyt nh ng ca mt trong cc kho ri lm tun t cho n kho

thn, tnh chi ph trong tng trng hp s dng n-1 kho .- Nu thy CFnCFn-1 th tip tc gim h thng xung n-2 kho bng cchlm tng t.

- Lp li qu trnh trn cho ti khi khng nhn c mc tit kim hnbc trc th dng li.

Hnh 3.9: Mi quan hgia slng kho hng v cc chi ph c lin quan

Ch gii:

1: Chi ph vn chuyn t kho n cc khch hng2: Chi ph vn chuyn t nh my n cc kho3: Chi ph vn d tr4: Chi ph x l thng tin kho5: Chi ph vn chuyn, bo qun ni b

6: Chi ph tng cngn*: s lng kho hng ti u

1

23

45

6

n* S lng kho hng

C

hiph


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CU HI N TP

1. Hy cho bit cc nguyn tc b tr v thit k kho hng. Gii thch ccnguyn tc .

2. Hy cho bit cc nhn tnh hng ti quyt nh thu hoc xy kho.

3. Hy cho bit cc im hn ch ca phng php trng tm trong vicxc nh v tr kho hng. T cho bit phm vi p dng ca phng

php ny.


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CHNG 4: BI TON PHN PHI V VN CHUYN HNG HA

4.1. Bi ton phn phi hng ha.

Ni dung ca bi ton l c n kho hng, mi kho c nng lc cung cp khcnhau v c ma im cn nhn hng, mi a im li c nhu cu v hng hakhc nhau. Mc tiu ca bi ton l tm cch phn phi hng ha t cc khon cc a im sao cho tng chi ph l nh nht.

Trong mn hc Ton Kinh T hay Ti u Ha, y chnh l bi ton vn ti.Theo Bi Minh Tr (2002), thut ton gii bi ton ny c chia lm 3 bc,c ni dung nh sau (y chng ti trnh by mt cch s lc, chi tit cathut ton ny c trnh by trong Bi Minh Tr (2002)) :

Bc 1: Tm phng n xut pht.

Bn cht ca bc ny l tm ba mt cch phn phi sao cho cc kho chahng th pht ht lng hng cha trong kho cn cc a im cn nhn hngth c tha mn ht nhu cu. N khng quan tm cch phn phi l tiu hay cha. Cng theo Bi Minh Tr (2002), ngi ta c th xut pht bng 1trong 3 phng php: phng php gc Ty- Bc, phng php cc tiu chi

ph ton bng, hoc phng php tim cn ca Vogel.

Bc 2: Kim tra iu kin ti u ca phng n.

Khi kim tra iu kin ti u, nu thy cc iu kin ti u c tha mn thdng li v phng n va c kim tra t ti u. Ngc li th chuynsang bc 3.

Bc 3: Chn phng n mi tt hn

Ni dung ca bc ny l iu chnh li vic phn phi hng ha. Lc ngita sc mt phng n mi tt hn phng n c, tuy nhin c th vn chat iu kin ti u.

V vy sau khi iu chnh li vic phn phi v c phng n mi tt hn phiquay li bc 2 kim tra. C nh thn khi c c phng n ti u thdng li.

Chng ta hy xem v d sau y:


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Bng 4.1: Bi ton vn ti

Chi ph vn chuyn 1 tn sn phmKho hng1 2 3 4 5

Nng lc

A 2 8 12 7 13 120B 14 7 18 4 9 70C 5 10 9 15 6 210D 8 3 7 10 10 150

Nhu cu 180 120 50 130 70 550

Ch gii:

- A, B, C, v D l cc kho hng vi nng lc tng ng l 120, 70, 210,v 150

- 1, 2, 3, 4, v 5 l cc a im cn nhn hng vi nhu cu tng ng l180, 120, 50, 130, 70- Cc con s nh trong bng l chi ph vn chuyn 1 tn sn phm t 1

kho n 1 a im, cc chi ph ny c k kiu l cij

Bc 1: Nu xut pht bng phng n cc tiu chi ph ton bng th ta cbng sau.

Bng 4.2: Gii bi ton vn ti vi phng n xut pht CTCP

Chi ph vn chuyn 1 tn sn phmKho hng 1 2 3 4 5 Nng lc

A 120 120B 70 70C 60 20 60 70 210D 120 30 150

Nhu cu 180 120 50 130 70 550

Nh trn bng ta thy cc kho hng pht ht hng cn cc a im nhnhng u c tha mn ht nhu cu.

Lc ny tng chi ph vn chuyn l: 2890

Bc 2: Kim tra iu kin ti u ca phng n

By gita a cc th vui v vj vo, vi:

u1= 0ui + vj= cijcc c phn phi hng ha


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Bng 4.3:a cc thvvo kim tra iu kin tiu

v1=2 v2=2 v3=6 v4=12 v5=3u1=0 120u

2=-8 70

u3=3 60 20 60 70u4=1 120 30

Sau tin hnh tnh i lng: ui+vj-cijcc khng c phn phi hngha. no c gi tr m ta ghi du (-), no c gi tr dng ta ghi du (+).

Bng 4.4: Kim tra iu kin tiu

v1=2 v2=2 v3=6 v4=12 v5=3

u1=0 0 - - +5 -u2=-8 - - - 0 -u3=3 0 - 0 0 0u4=1 - 0 0 +3 -

Ta thy trong bng c mang du (+), v vy phng n cha ti u. Ti (1,4) c gi tr dng ln nht (+5) ngi ta gi l sao (*).

Bc 3: Tm phng n mi tt hn

Ngi ta tm cc c phn phi hng ha to vi * thnh mt vng khpkn.

Bng 4.5: Ci tin phng n c

v1=2 v2=2 v3=6 v4=12 v5=3u1=0 0 - - * -u2=-8 - - - 0 -u3=3 0 - 0 0 0u4=1 - 0 0 +3 -

Trn cc nh ca vng khp kn ngi ta nh du (+) v (-) cho cc xen knhau, bt u t * mang du (+).

Trong cc mang du (-) ngi ta ly lng hng c lng phn phi nhnht lm lng hng iu chnh (qc).

By gicc mang du (+) ngi ta a thm vo mt lng hng bng qccn cc mang du (-) ngi ta bt i mt lng qc. Lc ny ta c phngn mi nh sau:


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Bng 4.6:Phng n phn phi mi

v1=2 v2=2 v3=6 v4=12 v5=3u1=0 60 60u

2=-8 70

u3=3 120 20 70u4=1 120 30

Phng n ny c chi ph 2590, tt hn phng n c. Tuy nhin mun bit n t ti u hay cha ta phi quay li bc 2.

Bc 2.1: Kim tra li iu kin ti u

Bng 4.7: Kim tra liiu kin tiu

v1=2 v2=2 v3=6 v4=7 v5=3u1=0 60 - - 60 -u2=-3 - - - 70 -u3=3 120 - 20 - 70u4=1 - 120 30 - -

Nh vy ta thy ti tt c cc khng c phn phi i lng ui+vj-cij umang du (-). Vy bi ton t iu kin ti u, vi tng chi ph nh nht l2590.

4.2. Bi ton vn chuyn hng ha.

4.2.1.Ni dung ca bi ton.

bi ton phn phi hng ha trong mc 4.1 chng ta gii quyt c vn: Mt kho hng trong h thng cn phn phi cho nhng a im no, vis lng l bao nhiu (V d: kho C phn phi hng cho cc a im 1, 3, 5vi khi lng tng ng l 120, 20, v 70).

Tuy nhin khi phn phi hng cho cc a im nh vi khi lng cxc nh th phng tin vn ti c cc cch di chuyn khc nhau, mi cch chomt chi ph c th khc nhau. mc ny chng ta cng xem xt bi ton: cc

phng tin vn ti sdi chuyn nhth no khi c phn cng chuyn chhng ha n cc a im nh vi khi lng xc nh.

Hy xem v d sau y: Kho hng O phn phi hng ha cho 2 a im A v B


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Hnh 4.1: Hai cch chuyn hng t1 kho n 2 im

Nhn trn hnh ta thy ch cn chuyn hng n 2 a im khc nhau c tnht 2 cch khc nhau.

y chng ta ginh rng di qung ng gia 2 a im c tnhtheo ng chim bay, tng khi lng vn chuyn ti c 2 a im cxc nh (hng s). V nu nh vy th r rng cch di chuyn th nht bao gicng tit kim hn cch di chuyn th 2. Mc tit kim c xc nh l:

e(A,B)= OA+OB-AB (4.1)

Nh vy nu phi chuyn hng cho 2 a im A v B nh trn th nh vn tis chn cch th nht vi chi ph t hn. Tuy nhin trong thc t ngi ta phivn chuyn cho rt nhiu a im cng mt ln (nhiu hn 2), v lc ny biton s trnn phc tp hn rt nhiu.

Thut ton gii bi ton ny c chia thnh 5 bc nh sau:

Bc 1: Tnh ton mc chnh lch

Nh trnh trn, cch di chuyn th nht bao gicng tit kim hn cchth 2 mt lng l e(A,B) (cng thc 4.1).

bc ny ngi ta tin hnh ly 2 a im cn nhn hng bt k trong s cca im cn nhn hng to thnh mt c p. Nh vy trong trng hp tng

qut, nu c na im cn nhn hng s c2

)1( nncp.

Sau tin hnh tnh ton mc chnh lch e ca tng cp theo cng thc 4.1

Bc 2: Phn loi cc cp chnh lch theo th t gim dn

Bc ny ngi ta tin hnh sp xp cc cp e tnh c theo th t gim

dn. Trong trng h p c cc c p c gi tr nh nhau th xp c p no trccng c.

A B

O

Cch 1

A B

O

Cch 2


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Bc 3: Chn cc cp trong danh sch to c bc 2.

Theo th t t trn xung di ngi ta tin hnh chn cc cp trong danh schbc 2. Ngi ta b qua cc cp to thnh vng hoc cha trnh vic iqua mt a im nhiu hn 1 ln.

Ngi ta c chn nh th cho ti khi chn c n-1 cp th dng li.

Bc 4: Kt thc

Sau khi chn c n-1 cp ngi ta tin hnh ni nh kho vi 2 trm mt c mt vng vn chuyn khp kn.

4.2.2. Mt sim khc bit trn thc t.

R rng chng ta thy rng phng tin vn ti ch c th chy c 1 vngkhp kn vn chuyn hng ha ti tt c cc a im cn nhn hng trongiu kin: nng lc ca 1 ln chuyn chp ng c tng nhu cu ca tt ccc a im. Tuy nhin trn thc tiu ny c th khng xy ra do phngtin vn ti b gii hn v nng lc. Lc ny ngi ta c th phi chia ra lm 2vng kn nh hn v lc s xut hin rt nhiu phng n vn ti vi 2 vngkn, mi phng n li cho mt chi ph khc nhau.

Ngoi ra nh ni phn 4.2.1, chng ta ginh di qung ng gia 2im l di on thng ni 2 im (hay ni cch khc l khong cch tnhtheo ng chim bay), v nh vy mi dn n mc tit kim nh cng thc4.1. iu ny l khng thc t bi 2 im:

- di qung ng trn thc t khng phi l di on thng.- C th chi ph theo cch 2 nh hn cch 1 rt nhiu nu: on ng AB

l on ng rt xu, i li kh khn, mt nhiu thi gian, ngoi racha ni ti vic c th trn on AB c cc trm thu ph theo quy nhv nhng trm thu ph ngoi quy nh khc.

Nh vy 2 im hn ch ni trn nh hng n phng php v kt qu cathut ton. Cu hi t ra l: nu cc tnh hung xy ra th thut ton trongmc 4.2.1 cn thay i nh th no?

Cu tr li dnh cho hc vin.


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CU HI N TP

1. Kho O c nhim v phn phi hng ha cho cc a im A, B, C, D, E,v F. Khong cch gia cc a im v kho c cho nh sau:

Khong cch n trm (km)TRM Nhucu O A B C D E F

A 2.0 16 0 27 43 34 24 18B 0.8 15 0 48 17 27 40C 1.6 29 0 16 35 53D 2.5 18 0 19 41E 0.8 15 0 23F 1.4 26 0

- Tm con ng vn chuyn ti u nu phng tin vn ti khng b giihn v nng lc.- Lp lch nhn v pht hng ti cc a im, bit rng: t hot ng t

8h sng, di chuyn vi vn tc trung bnh 40 km/h, thi gian bc dhng cc a im l 10 pht/ln

- Tm con ng vn chuyn ti u nu bit rng ti trng ca t l 5tn, 3 tn.

2. Gii cc bi ton phn phi hng ha sau y:

100 120 130 180170 7 5 0 4

110 3 2 6 5

150 3 5 2 7

90 85 80 75

120 11 6 4 8

150 9 3 4 5

140 7 4 5 6

70 80 85 90

100 5 7 9 8

90 6 4 7 5

110 4 7 6 9


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70 85 80 90

110 6 7 4 5

130 9 8 6 5

150 6 4 7 9

3. Khi chn ra c n-1 cp chnh lch theo th t gim dn nh trnh bymc 4.2.1 ta s c c con ng vn chuyn ti u. Hy cho bit ngha ca gi tr ca tng n-1 cp chnh lch l g.


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CHNG 5: LP K HOCH SN XUT TI U

5.1. Mt s khi nim cbn trong Qun l sn xut.

Chu k sn xut: chu k sn xut l khong thi gian t lc a nguyn vtliu vo sn xut cho ti khi c c thnh phm.

Khi lng ti ch phm: khi lng ti ch phm l lng nguyn liu, bnthnh phm ang nm trn dy chuyn sn xut.

Mi quan h gia chu k sn xut v khi lng ti ch phm c xc nhnh sau:

K.lng ti chphm = C.k sn xut (thng) nhu cu sn phm/thng (5.1)

Thi hn giao hng: thi hn giao hng l khong thi gian t lc nhn cn hng cho ti khi bn giao c sn phm cho khch hng.

Ty thuc vo loi hnh sn xut, sn xut d tr hay sn xut theo yu cu, mchu k sn xut c th ln hn hoc nh hn thi hn giao hng. Nu sn xuttheo yu cu th thi hn giao hng lun ln hn chu k sn xut, cn nu snxut d tr th ngc li. Mi quan h ny c m t nh trong hnh sau y:

Hnh 5.1: Sn xut theo yu cu

Hnh 5.2: Sn xut dtr(bn thnh phm)

2 3 41

Chu k sn xut

Thi hn giao hng

Thi gian

2 3 41

Chu k sn xut

Thi hn giao hng

Thi gian


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Hnh 5.3: Sn xut dtr(thnh phm)

Ch gii:

Thi im t hng

Thi im a nguyn vt liu vo sn xut

Thi im c c thnh phm

Thi im giao hng

5.2. Bi ton quy hoch ng.

Hnh 5.4: Bi ton quy hoch ng

Ni dung ca bi ton quy hoch ng nh sau:

Mt ngi a th c nhim v di chuyn t thnh ph Alpha n thnh phOmega. Ngi a th chc di chuyn theo hng mi tn nh trn hnh

5.4. Hy ch cho ngi a th ny con ng ngn nht t Alpha n Omega,bit rng chi ph i li gia cc a im (cij) c cho nh trong bng diy:

1

2

3

4

5

6

7

8

OmegaAlpha

2 3 41

Chu k sn xut

Thi hn giao hng

Thi gian

2

3

4

1


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Bng 5.1: Chi phi li gia cc a im

a im Cij a im CijSTT

i jSTT

i j

1 alpha 1 7 10 3 6 6

2 alpha 2 4 11 4 7 33 Alpha 3 5 12 4 8 2

4 1 4 4 13 5 7 5

5 1 5 3 14 5 8 4

6 2 4 9 15 6 7 4

7 2 5 5 16 6 8 1

8 2 6 8 17 7 Ome. 2

9 3 5 3 18 8 Ome. 4

Thut ton gii bi ton ny c trnh by nh sau:

Bc 1:

u tin ngi ta chia bi ton di chuyn thnh cc giai on, mi giai on ltp hp tt c cc a im m ngi a thc tht chn n ti mt thiim no . Trong trng hp ny nu khng k thi im t chn c nch (Omega) th bi ton c chia thnh 4 giai on nh sau:

Hnh 5.5: Bn giaion trong qu trnh di chuyn

Bc 2:

Mi mt giai on ngi ta phi l p ra mt bng, cc bng ny c cu trcging nh nhau.

1

2

3

4

5

6

7

8

OmegaAlpha

Giai on 1 Giai on 2 Giai on 3 Giai on 4


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Bng 5.2: Bng khi qut thut ton quy hoch ng

Trng thi ca h thng giai on n+1 Quyt nh ti uGiai on n

j Chi ph min im n

i chi ph nh nht i ti

quajn omega fn(i) gn(i)

Trng thi ca hthng giai on n

Ch gii:

- Cu trc ca bng gm 3 phn chnh: (1) Trng thi ca h thng giaion n, (2) Trng thi ca h thng giai on k tip n+1, v (3) Ccquyt nh ti u: chi ph ti u, im di chuyn n ti u.

- Trng thi ca h thng giai on bt kc th hin bi a imm ngi a th c tht chn ti trong giai on .- fn(i): Chi ph nh nht i t thnh ph i thuc giai on nn Omega.

- gn(i): a im ca giai on n+1 cho chi ph cc tiu fn(i) khi t giaion n ngi ta phi xut pht ta im i.

- cij: chi ph i tinj.

Vy trong bi ton c th ny ta phi lp ra 4 bng c cu trc nh bng 5.2.

Mt iu ng lu l trong thut ton quy hoch ng ngi ta tnh ton ccs liu cho bng ca giai on cui cng trc, v ngc li, bng ca giaion u tin sc tnh cui cng.

C th nh sau:

Giai on 4:

Chi phnj Q ti uGiai on 4

Omega f4(i) g4(i)

7 2 2 OmegaT thnh

phi 8 4 4 Omega

Giai on 3:


7 8 f3(i) g3(i)

4 3+2 2+4 5 7

55+2 4+4 7 7

T thnh

phi6 4+2 1+4 5 8

)(min)( 1, jfcif njij

n ++=


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Giai on 2:


4 5 6 f2(i) g

2(i)

1 4+5 3+7 9 4

2 9+5 5+7 8+5 12 5T thnh

phi3 3+7 6+5 10 5

Giai on 1:Chi phnj Q ti u

Giai on 11 2 3 f1(i) g1(i)

T thnh

phi Alpha 7+9 4+12 5+10 15 3

Bc 3:

Nhn vo bng cui cng ta thy ngay chi ph nh nht i t Alpha vOmega l 15, cn ng i phi tm ngc li t bng ca giai on 1 trvtrc s thy:Alpha- 3- 5- 7- Omega.

Trit l ca QUY HOCH NG:

5.3. Bi ton lp k hoch sn xut.

Cng ty X d bo mc nhu cu sn phm trn th trng nh sau:

Bng 5.3: Nhu cu vsn phm ca cng ty X

t 1 2 3 4 5

dt 2 5 4 2 4

Hy lp k hoch sn xut ti u nht p ng ti a nhu cu trn, bit rng:chi ph iu chnh h thng sn xut: 150 USD /ln, nu trong k khng snxut th khng tn chi ph ny; chi ph tn kho: 10 USD /sn phm /k; v nnglc sn xut ca cng ty c cho nh sau:

D quyt nh qu kha bn n trng thi no hin ti th bn cnglun phi tm c quyt nh ti u t n trng thi tng lai mongmun.


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Bng 5.4: Nng lc sn xut ca cng ty X

t 1 2 3 4 5

P=200 2 2 3 3 3

P=250 3 3 3 3 3

Bng 5.4 th hin nng lc sn xut ca cng ty X, v dk 1 cng ty c khnng sn xut ti a 2 sn phm vi mc gi thnh l 200 USD /sn phm, numun sn xut sn phm th 3 trong k ny th cng ty phi chu mc gi thnh250 USD /sn phm, tuy nhin vi mc gi thnh 250 USD/sn phm th cngty cng ch sn xut c ti a l 3 sn phm. Ni tm li trong k 1 cng tych c th sn xut nhiu nht l 5 sn phm (2+3).

Gii bi ton ny ngi ta phi p dng thut ton quy hoch ng v trong bi

ton ny phi lu my im sau y:

- Trng thi ca h thng c th hin bi mc tn kho u k- Mc tn kho cui k ny s bng mc tn kho u k sau- Lng sn xut trong k i= Tn cui k i (tn u k i+1)+ mc tiu

th trong ki- tn u ki- Mi mt kc coi l mt giai on- Chi ph tn kho u k no c tnh cho k, chi ph tn kho cui k

c tnh cho k sau- Bng khi qut thut ton c cu trc nh sau:

Bng 5.5: Bng khi qut thut ton ca bi ton lp khoch sn xut

Mc tn kho u k n+1 Q ti u

Kn j

Chi ph

min

Lng SX

ti u

.

i

Chi ph nh nht sn xut t kn

cho ti k cui cng vi mc tn

u knli, tn u kn+1lj

fn(i) gn(i)

Mc tn

kho u

kn

bi ton n gin ta ginh mc tn kho ti a cui mi k l 2 sn phm.Nh vy bi ton ny c gii nh sau:


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Cng nh bi ton quy hoch ng, n y ta thy c chi ph sn xut vlu kho ti u l 4360 vi k hoch sn xut tng ng l:

Bng 5.6: Khoch sn xut tiu

T 1 2 3 4 5

dt 2 5 4 2 4

KHSX 2 5 4 3 3


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CU HI N TP

1. Hy cho bit ngha ca Trit l Quy hoch ng

2. Lp k hoch sn xut ti u, bit rng:

t 1 2 3 4 5

dt 2 5 4 2 4

P=150 2 2 3 3 3

P=200 3 3 3 3 3

Bit rng chi ph iu chnh h thng sn xut l 200 USD /ln, chi ph lu khol 15 USD /sn phm /k. Gi thit mc tn kho ti a cui mi k l 2 sn

phm.

3. Lp k hoch sn xut ti u, bit rng:

t 1 2 3 4 5

dt 3 3 5 4 2

P=150 2 4 3 6 1

P=200 2 1 3 0 1

Bit rng chi ph iu chnh h thng sn xut l 150 USD /ln, chi ph lu khol 15 USD /sn phm /k. Gi thit mc tn kho ti a cui mi k l 2 snphm.


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CHNG 6: VN TI V CC LOI HNH VN TI

6.1. Vai tr ca vn ti trong Logistics.

Hnh 6.1: M hnh ng ni v im nt

- Trong m hnh ng ni v im nt, vn ti l ng ni gia cc

im cnh (nt)

- Khi m cng ty hot ng trn phm vi ton cu th chi ph vn ti thmch ngy cng trnn quan trng. S liu ca Coyle (2003) cho thy:

Nm 1999, cc cng ty Mchi khong $554 t cho vn chuyn hng ha, hay9,9% GNP. Trong khi nm 1993 l 397 t hay 6,3% ca GDP.

Nm 1999, nu tnh theo % ca doanh thu th chi ph vn ti l 3.24%, chi phkho hng l 1.84%, chi ph dch v khch hng l 0.48%, qun l 0.38%, v chi

ph lu gil 1.52% ca doanh sbn hng.

- Vn ti cng to ra gi tr ra tng bng cch cung cp li ch v khnggian v thi gian cho hng ha ca cng ty.

- Vic chi cho hat ng vn ti cng chnh l chi ph nh i vi hngtn kho. Nu chi ph vn ti cao th chi ph cho hng tn kho th p vngc li.

Nh bn l

Kho hng

Kho hng

Nt

Nt

Nt

Nt

Ntngni

Nh bn l

Nh my

ngni

ngning

ni

ngni


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Hnh 6.2: Mng li cung cp

- Vn ti l im ni hu hnh gia cc nh cung cp vi khch hng.

6.2. Cc loi hnh vn ti.

Phn loi theo loi phng tin vn ti, cc loi hnh vn ti c chia thnh 5loi sau y:

Hnh 6.3: Cc loi hnh vn ti

- Vn ti ng b

- Vn ti ng thy- Vn ti ng st

nngg bbnngg sstt

nngg kkhhnngg

nnggnngg

nngg tthhyy

Nh my

Trung gianphn phi

Khch hng

Nh cung cp


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- Vn ti ng khng- Vn ti ng ng

6.2.1. Vn ti ng b.

Vn ti ng b c c im:

- Mc tip cn cao- Thi gian trung chuyn nhanh hn ng st v ng thy- tin cy bnh hng ln bi thi tit- Kch cca xe vn ti nh ph hp vi chin lc hng tn kho thp v

nhanh chng np li hng vo kho- Chi ph vn ti hi cao so vi ng st v thy nhng i li l nhanh

hn

6.2.2. Vn ti ng thy

Vn ti ng thy ni b c c im:

- L loi hnh c chi ph tng i thp: khng phi u t cho xy ngi, d dng gia nhp hay ra khi ngnh

- Thng vn chuyn hng ha c gi tr th p, dng hng khi nhkhong sn, sn phm nng nghip, lm nghip vi c ly vn chuyn di

- Chi ph vn ti thp nhng thi gian trung chuyn di- Mc tip cn thp nhng nng lc vn ti th ln

Vn ti ng thy quc t c c im:

- Tu vn chuyn hng ha thng dng:C sc cha hng ha lnVn ti thng c thc hin di dng hp ngC nhiu tu c lun cn cu bc xp hng

- Tu vn chuyn hng khi:

Thit kc bit chkhong snC th dng chnhiu loi hng ha

6.2.3. Vn ti ng st

Vn ti ng st c c im:

- Kh nng vn chuyn nhiu loi hng khc nhau hn so vi cc loihnh khc

- S lng nh cung cp dch v ny l khng nhiu.

Vit Nam: 1 nh vn tiM: mt vi nh vn ti


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- Tu ha l h thng vn ti ng di, vi khi lng ln (chi ph cnh cao)

- Mc tip cn khng cao- Thi gian trung chuyn khng u v thng di

6.2.4. Vn ti ng khng

Vn ti ng khng c c im:

- Bt c hng vn ti hng khng no cng c th chhng ha, mc dvy c mt vi hng khng chg khc ngoi hng ha

- Cu trc gi vi chi ph bin i cao so vi chi ph cnh- Thi gian trung chuyn l nhanh nht trong cc loi hnh vn ti, nhng

gi cc vn ti th cao nht- Thng vn chuyn hng c gi tr cao, khi lng thp- Mc tip cn v nng lc l thp- tin cy ph thuc vo thi tit nhiu hn so vi cc loi hnh khc

6.2.5. Vn ti ng ng

Vn ti ng ng c c im:

- Thng dng vn chuyn du, kh- Khng ph hp cho vn ti thng thng- Mc tip cn thp- Chi ph cnh cao, chi ph bin i thp- Li ch chnh l gi cc vn ti thp

6.2.6. So snh cc loi hnh vn ti

Bng 6.1: So snh cc loi hnh vn ti

Ch tiungSt

ngB

ngThy

Hngkhng

ngng

Chi ph 3 4 2 5 1

Thi gian trung

chuyn3 2 4 1 ---

tin cy 2 1 4 3 ---

Nng lc 1 2 4 3 5

Mc tip cn 2 1 4 3 ---

An ton 3 2 4 1 ---


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6.3. Cc ch tiu nh gi nh vn ti.

Bng 6.2: Cc chtiu nh gi nh vn ti (theo thtquan trng)

STT Thnh t quyt nh la chn Xp hng1 tin cy ca thi gian trung chuyn 12 Chi ph vn ti 23 Ton b thi gian trung chuyn 34 Mc sn sng ca nh vn ti trong m phn gi 45 Mc n nh v ti chnh 56 Thit b 67 Tn sut dch v 78 Dch v vn chuyn giao nhn 89 Hng ha mt mt hay h hng 9

10 Tin hnh cht hng, giao nhn 1011 Cht lng ca nhn vin vn hnh 1112 Theo di vn chuyn 1213 Mc sn lng ca nh vn ti m phn mc dch v 1314 Linh hot trong thi gian biu 1415 Dch v ko moc 1516 Qu trnh gii quyt khiu ni 1617 Cht lng ca nhn vin tip th cng ty 1718 Thit bc bit 18


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CU HI N TP

1. Hy cho bit vai tr ca cng tc vn ti trong Logistics.

2. Hy nu c im ca cc loi hnh vn ti.

3. Hy cho bit cc ch tiu nh gi mt nh vn ti.

4. Theo Grard Chevalier v Nguyn Vn Nghin (1998), phng chmhnh ng ca phng php OPT (Optimized Production Technology-Cng ngh Sn xut Ti u) trong qun l sn xut l: Tng nhng tiu cc b khng bng ti u ton b h thng. Trong khi trongni dung ca mn hc ny, chng ta thy rng mi chng u ch niti vic ti u cng vic ca mnh m khng cp ti cc cng vickhc cng nh ca ton b h thng chui cung cp. Anh, ch hy cho

bit iu c i ngc li phng chm hnh ng ca OPT haykhng? Hy gii thch c th!


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TI LIU THAM KHO

1 NGUYN VN BA. Phn Tch V Thit K H Thng Thng Tin. Nh xutbn i Hc Quc Gia H Ni, 2003.

2 BI MINH TR. Ti u Ha. H Bch Khoa H Ni, 2002

3 COYLE, JOHN J.; BARDI, EDWARD J.; LANGLEY, JOHN, JR. TheManagement of Business Logistics: A Supply Chain Perpective. 2003

4 GRARD CHEVALIER, NGUYN V N NGHI N. Qun L Sn Xut. Nhxut bn Thng K, 1998.

5 VU DINH NGHIEM HUNG, 2002. Evaluation of Projects Based on EconomicCriteria: A Fuzzy Logic Approach. Masters Thesis, Asian Institute ofTechnology, Bangkok Thailand 2002.

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