NGHIEN Ctru AP DUNG BAI TOAN VAN TAI V 6 l RANG BUPC KHUNG THOfl GIAN TAI DIEM HANG
TRONG DICH VU LOGISTICS
NGUYEN MINH HIEU
Bg mdn Van lai Dudng bg & Thanh pho Khoa Van tdi - Kinh te
Trudng Dgi hgc Giao thong V^n tdi Tdm tdt: Tdi uu hda cdng tdc Idp hdnh trinh vgn tdi dugc coi Id mdt trong nhirng vdn di mdu chdt di ndng cao chdt lugng dich vg vgn tdt Logistics. Vdi muc lieu Idi uu (thieu hda) quang duong van chuyin, phuang phdp lap hdnh trinh (bdi todn van tdi) vdi rdng budc khung thai gian tgi cdc diem hdng (VRPTW) dugc su dung phd biin. Phuang phdp ndy cho phep xem xet ddng thdi nhiiu biin so (Van tdc ky thudt, Thdi gian xep-dd. Thdi diim cd thi giao nhgn hang...) trong qud trinh Igp phuang dn.Sau day, tdc gid se trinh bdy chi Hit qud trinh dp dung phuong phdp tren de xdy dung phuong dn hdnh trinh cho Trung tdm Logistics ICD Tien San;
so sdnh. ddnh gid phuang dn de xudt vdi phuang dn hi4n dang dugc dp dung.
Abstract: The optimized vehicle route network is one of the key elements to improve Logistics. With the objective lo minimize the travel distance, the application of the vehicle routing problem with time windows(VRPTW) is popular in worldwide because it enables dispatchers to build up the operating plans based on the speed, the loading time, the allowed lime of (un) loading goods in each customer's warehouse... In this paper, the author is going to present the suggested operating plan found by applying VRPTW method in the case of the Tien Son ICD Centre, subsequently making the comparison to assess the ejficiency and effectiveness of the applicgiion.
I. DAT VAN DE
Bai todn van tai eg bdn (VRP) vdi cdc rdng bugc vl trgng tai, sd lugng phuong tiSn... vdham muc tieu thieu hda quang dudng van chuyin dugc thira nhan vd su dyng phd bien trong boat ddng van tai - 1 khdu quan trgng ciia chudi dich vy Logistics. Tuy nhien, hoat dgng van tdi chju nhieu tac dgng ciia yeu td ben ngoai nhu td chiic, dieu tiet giao thdng va dac biet Id khung thdi gian (nhOng thdi diem) cd thi giao nhan hdng tgi moi dilm hang. Do do bai todn vdn tai cdn thiit phdi cd su dilu chinh dl trd n6n phii hgp ban vdi thuc tl, ndng cao tinh kha thi ciia phuong dn dl xudt.
Xudt phdt tir nhu cdu dd, bai bao da tiln hdnh dp dyng phien bdn md rdng cua bai todn ca ban (dua them dieu kien rdng budc ve khung thdi gian giao nhdn hang - VRPTW) dl tinh toan vd lya chgn phuang an hdnh trinh cho Trung tdm ICD Tien San, ddng thdi cung so sdnh phuong an dl xudt va phuong dn hien dang dugc dp dung de cd su danh gid khach quan, chi tilt vd thuylt phuc.
104 Tgp chi KHOA HOC GIAO THONG V ^ TAI So 49 - 12/2015
II. NOI DUNG
2.1. Quy trinh thuc hiln nghien cihi
f l ) Xac dinh khoang radi;Lap ma trjin qiiSnt; dirimg dirye nil ngan giiJa cac diem hai^ va vtti diaii xuSt phai
^2\ ^^'^ ^^^ diem co quSng diiane.
dirpc rut ngan Icm nhat(liSp theo)
Dua ra kei qua ve cae hanh trinh l^p dui^c va Iinh toan mgt sd chi tieu
khai thac ky thuat ca ban
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Hinh 1. Quy trinh thifc hien nghien cuu - Bu&c 1: Xdc dinh vd lap ma trgn 0-D cua qudng ducmg dugc rut ngdn:
Ddu ti8n, cdn xac djnh khoang each giu'a cac dilm hang (D,j) va giiJa cac dilm hdng vdi dilm xudt phat (kho) (D^,) dl lap ma trdn 0-D giita cac dilm. Tilp theo, tren co sd ma trdn 0-D, tiSp tyc tinh qudng dudng dugc nit ngdnkhi hoan thdnh nhiem vy van tdi gitta cdc ^\km(S,^:
Sij = D„i+D„j-Dij i= 1,2,3,....,n; j=l,2,3,....,n Vdi Sij la lugng (qudng dudng) tilt kifim Do, Id khoang cdch tir O (dilm xudt phat) tdi i Doj Idkhoang cdch tir O (diem xuat phat) tdi j
D,j la khodng cdch tCr i tdi j S,j = (D,.,+D„.+D„j+DjJ - (Do,+D,j+Dj^
Hinh 2. Gidi thich cdch tinh S,, Tir sd lieu S,j, lap ma trdn quang dudng dugc riit ngan giira cdc diem.
- Budc 2: Xdc dinh diem co qudng duong dirge rdt ngdn l&n nhat:
Tren co sd ma trdn da lap dugc d budc 01, tien hdnh xdc dinh diem cd quang dudng nit ngdn Idn nhdt Idm dilm bdt ddu cho hdnh trinh. Vdi each lam nhu vay, nhung dilm cd qudng dudng riit ngdn Idn nhdt se dugc uu tien thyc hi§n ket ndi trudc vdi ky vgng giiip phuang an hdnh trinh cudi ciing cd the tilt kiem dugc tdng qudng dudng van chuyin g mdc tdi da cd thi.
- Buac 3: Thda man dieu kien rang bugc ve khd nang vdn chuyen
Ket ndi giu'a cac dilm khien tdng trgng tdi hang (ho§c thi tich hang) tich luy tren phuang ti?n Idn hon.kha nang cho phep thi viec ket ndi tdi diem dd la khdng kha thi, cdn phdi quay lai budc 02 de tim kilm dilm cd qudng dudng dugc rut ngdn eye dai tilp theo.
T?p chi K H O A H O C G I A O T H O N G VAN TAI So 49 - 12/2015 105
- Buac 4: Kiem tra dieu kien ve rdng huge th&i gian
Khi dilm thda man dieu kien d budc 3, cdn tinh todn tilp vl thdi gian dl cd thi tiep can tdi dilm hang dd (thdi gian Idn banh tren dudng) vd thdi gian cdn thiit dl thyc hien xIp (dd) hang tai diem vdi rang budc Id Id tdng thdi gian khdng vugt qua gidi ban thdi gian dugc phep giao nhdn hdng (khung thdi gian) tai diem hang. Neu khdng thda mdn tilp tuc quay lai budc 02.
- Buac 5: Biim dugc dua vdo hdnh trinh
Neu nhu diem xem xet tilp tuc thda man dilu kign vl khung thdi gian thi diem dd se dugc kSt ndi vdo hanh trinh.
- Budc 6: Kiem tra xem cdn diem ndo co the dugc dua vdo hanh trinh
Ban chdt ciia budc ndy Id lap lai qud trinh tir budc 2 tdi budc 5 tuy nhien d quy md nhd han, vdi nhiJng diem chua dugc dua vdo hanh trinh va chua bi logi trong cdc vdng lap tim kiem trudc.
Neu khdng cd them dugc diem phii hgp thi hanh trinh dugc xdc lap, chuyen sang budc tiep theo.
- Budc 7: Kiem tra kha ndng lap them dugc hdnh trinh mai
Ddy Id budc cd quy trinh gdn gidng vdi budc 6 nhdm dam bdo khdng cd dilm nao tren mang khdng cd tuyen van tdi tiep can. Khi da xdc dinh duoc rang tdt ca cac diem deu cd hanh trinh thdng qua thi coi nhu vdng lap tim kilm hanh trinh dd kit thiic.
- Birac 8: Dua ra kit qud cudi ciing va ddnh gid ket qud nghien cihi
Ddy Id budc tdng hgp tai ket qua ciia cdc budc tren vdi viec cu the hda cdc hdnh trinh da lap dugc. Ddng thdi, cdn thiit tinh toan mdt s6 chi tieu khai thac ky thuat co ban de tir do cd su so sanh, danh gia, nhdn xet vl sy uu viet cung nhu nhiing han chi (cd thi cd) ciia phuong an dl xudt.
2.2. Ap dung bai toan cho Trung tam Logistics ICD TiSn Son a. Gi&i thiiu ICD Tien Sffn
ICD Tien Son la mdt trong nhiJng cdng c^n hien dai vd Idn nhdt tai khu vuc miln Bdc theo md hinh Logistics 3PL, vdi cac djch vy kho bai, van chuyin, hdi quan, bai Container...
b. MtfC tiiu cua bdi todn
- Dua ra hdnh trinh de xudt cd tdng qudng dudng van chuyen tdi uu hon (nhd hon) phuong dn hien tai thda man cac dieu kien rang huge.
- So sdnh, danh gia tdng quat cac chi tieu khai thdc ky thuat khac giira phuang an 6k xudt va phuong an hien dang ap dung de tim ra phuang an tdt hon.
c. Cdc rdng bugc cua bdi todn dp dung cho ICD Tiin San
Cac rang budc ddi vdi bai todn khi dp dyng cho ICD Tien Son gdm: Loai hdnh trinh: Hanh trinh phdn phdi; Loai hang hoa van chuyin: Hang my phdm Loreal vdi yeu cdu van chuyen va xIp do nhe nhang, xep theo ciing chilu dl han chi tinh trang xd djch, mop meo; Diim hdng.
106 Tap chi KHOA HOC GIAO THONG VAN TAI So 49 - 12/2015
Kho ciia Trung tdm ndm tai Bdc Ninh trong khi 25 diem hdng cdn phdi van chuyen la cac shop hay cira hdng tai thdnh phd Ha N^i; Gi&i hgn khd ndng vgn chuyen: Hang my pham id hang nhe do do thudng khdng tdn dyng het khd ndng ve trgng tai ciia phuang tien ma chii yeu bj gidi han bdi the tich ciia thiing xe. Can cir theo quy cdch ddng gdi cua 1 thiing hang, thi 01 xe tai loai nho (1.5 tdn) dugc sd dyng tren tuyin se van chuyin dugc tdi da la 15 thiing hang (Qmax = 15);
Van toe: Doan Bdc Ninh - Ha Ndi: VN^oa. ihinh = 40 Km/h. Trong pham vi thdnh phd Ha Ngi:
Dilu kien m§t do giao thdng day ban vd cung bj gidi h^n tdc do do dd dinh muc: VNO, ihanh= 25- 30 Km/h; Thdi gian dot vd kiem dim hdng hoa: Phu thugc tryc tilp vdo quy md don hdng cdn giao tai mdi diem. Ddy la qua trinh tuong ddi mat thdi gian, theo khdo sdt, thdi gian dl dd vd kilm dim 1 thiing hdng Id khoang: 15 phiit/thiing; Khung thai gian: Cdc dilm hang cd khung thdi gian dao ddng trong ngay tuy nhien tap trung chu ylu vao cudi budi sang va ddu gid chilu;
Thdi diem xe xudt phat: De dam bdo hieu qua, thdi dilm xudt phat ciia xe tir kho tai ICD khdng bj gidi han. Gid thiet rdng xe dugc bd tri xudt phat vao thdi dilm bdt ky dl ddm bdo rdng din diem ddu tien cua hdnh trinh cd the dd hang ngay lap tuc (khdng phai chd dgi); Phuang tien co thi sir dung tren tuyen: Ld loai xe 1,5 tan. Sd lugng xe tdi da cd thi sir dung Id 08 xe.
d. Kit qud phuang dn hdnh trinh
Bdng I. Cdc hdnh trinh lap dugc khi su dung phuang phdp VRPTW
Hanh trinh 1. k-3-l-k 2. k-7-4-l3-ll-14-k 3. k-6-9-k 4. k-24-16-21-10-k 5. k-5-18-8-k 6. k-2-23-19-22-k 7. k-25-15-20-12-17-k
TSng hfrp 7 bdnh trinh
Quang diro'ng (km) 70,3 67,1 46,9 86,6 69,1 .83,0 80,3 S03,3
Tong thoi gian thirc hi^n nhiem vu van tai (gid)
12,65 9,23 6,91 10,46
9,52 10,37 8,99 6S,IS
Tong $0 thung hang v^n chuyen (thitng)
14 .14 10 14 12 11 13 SS Chu thich: kldky hi^u cho kho cua Trung tdm ICD Tien San tgi Bdc Ninh
Kit qua tinh toan cho thdy, tdng qudng dudng xe chgy cua ca 07 hdnh trinh la khoang 500 Km trong dd. tdt cd cac hdnh trinh diu Id hdnh trinh ghep, ket ndi tir 2 tir dilm hang trd len.
Hdnh trinh dai nhdt la hdnh trinh sd 04 vdi quang dudng 86,6 Km. Hanh trinh di qua nhilu dilm hdng nhdt Id hdnh trinh sd 02 vd 07 (di qua 05 diem) tuy nhien ddy hdu hit la cdc dilm cd cy ly gdn nen thai gian cdn thiet dl hoan thdnh nhiem vy vgn tai Idn lugt la khoang 9,3 gid va 9,0 gid. Hanh trinh cd tdng thdi gian thyc hien nhiem vu van tai Idn nhdt Id hdnh trinh 01. Mdc Tgp chi K H O A H O C G I A O T H O N G VAN TAI So 49 - 12/2015 107
du chi qua 02 dilm hdng vdi qudng dudng (70,3 Km) nhd hon cdc hdnh trinh khac tuy nhien do thdi gian chd dgi Idn nen tdng thai gian hodn thdnh nhiem vu van tdi len tdi 12,65 gid.
Tdng thdi gian cdn thiit dl hodn thdnh cd 07 hdnh trinh Id 68,15 gid. Thdi gian ndy bao.
gdm ca thdi gian chd dgi tai cac dilm hdng, thdi gian dd hang vd thdi gian xe chay tren dudng.
Vdi 07 hdnh trinh, sd phuong tien can thiit Id 07 xe, thda man dilu -kien ve gidi han so lugng xe cd the sd dung (08 xe).
2.3. Phan tich ket qua ap dung bai toan VRPTW va phuvng an hien tai ciia Trung tSm Bang 2. So sdnh ket qud dp dung bdi todn VRP TW vd phuang dn hi4n tgi ciia Trung tdm TT
1 2 3 4
5 6 7 8
Tieu chi so sdnh
T6ng quang du6ng xe chay (Km) T6ng thai gian cho dgi (gia) Tong thai gian d& hang (gia) Tong thai gian xe chay (gi(»)
Tong thai gian (gift) H^ s6 sir dyng th^ tich binh quan So lir(?ng xe ho?t dgng (So hanh trinh) So hanh trinh don (chi co 1 diem hang)
Gia trj P. dn hien tgi (I)
543,7 38,823 14,75 14,307 67,88 0,733 08 01
K. qud bdi tadn (2)
503,3 39,808 14,75 13,592 68,15 0,849 07
0
Chenh Ifch
^-(l)-(2) 40,4 -0,985
0 0,715 -0,27 -0,116 01 01
- Tong qudng duong xe chgy: Do phdi hgp dugc cac hanh trinh hgp ly hon n6n tdng qudng dudng di chuyen trong I ngdy cua phuong an de xudt tiet kiem dugc 40,4 Km (tucmg ducmg khoang 8%). Dieu nay cho phep tilt kiem chi phi lign quan nhu nhien lieu, sdm Idp...
- He sd su d{ing the tich binh qudn cua thiing hang: Tdng khoang 16% so vdi phucmg dn hi8n tai, nhu vdy kha ndng vgn chuyin cua phuong ti§n dugc sir dyng triet dl han.
- Sd lugng xe cdn thiit ho0 dgng: Do phuong dn dl xudt chi cd 07 hanh trinh trong khi s6 lugng hdnh trinh cua phuong an hi8n tai la 08 nSn nhu cdu phuong tien gidm 01 xe.
- Tdng th&i gian cho dgi: Se Id uu thi cua cac phuong ancd hanh trinh don (hanh trinh chi cd 1 dilm hang) vi khi do phuang tien cd thi chii dgng thdi gian xuat phdt nen khdng mat thdi gian chd dgi. Ngugc lai, cdc hdnh yinh ghep thudng sg xudt hien thdi gian chd dgi (trudc khi tdi thdi dilm dugc dd hang) do sy khdc nhau vl khung thdi gian dd hang (tai cdc dilm) tr6n ciing 1 108 Tap chi K H O A H Q C GIAO T H O N G VAN TAI So 49 - 12/2015
hdnh trinh. Kit qud tinh todn chi ra rdng, vdi viec cd nhilu hdnh trinh ghep nen phuong an de xudt cd thdi gian chd dgi Idn hon (khoang gdn 1 gid, tuong duong 2,5%).
- Tong thai gian thuc hien nhiem vu van tdi: Do phuang an de xudt cd the manh ve giam thdi gian van chuyin tuy nhi6n thdi gian chd dgi lai keo ddi nen khi so sanh ve tdng thdi gian thyc hien nhiem vu van tdi tren tdt ca cdc hdnh trinh thi ca 2 phuong an the hien ket qua tuong ddng vdi sy chenh lechkhdng dang ke (15 phut, tuong duong 0,5%).
Danh gia tong quat:
Phuang dn de xudt (dugc xdc dinh thdng qua bdi todn VRPTW) dat dugc muc tieu dl ra dd cd tdng quang dudng van chuyin nhd hon phuang dn hien tai. Ddng thdi, phuang dn ciing thi hi?n uu the ve viec tiet kiem sd lugng phuong tien cdn thiet boat dgng, ndng cao dugc hi$u qua sir dung ndng luc van chuyen ciia phuang tien. Tuy nhien han che nam d viec thdi gian chd dgi cd the tang len khi ket ndi nhilu diem hang tren hanh trinh ddn tdi tdng thdi gian thuc hien nhi?m vu van tdi cua 2 phuong an Id tuong ty nhau.
Vdi phan tich nhu tren, cd thi nhgn xet rdng: Phirong an de xudt cd hi£u qua hon phuorng an bien tai vi nd cho phep Trung tam hoan thanh nhiem vy van tai vdi it cdc yeu td dau vao hon (phuong tien, nhien lieu, ngudi lai...) trong thdi gian tuong duong.
III. KET LUAN
Bdi bdo da trinh bdy mgt cdch khoa hgc vd chi tiet cac ngi dung gdm:
- Quy trinh thyc hien, muc tieu vd cac dieu kien gidi han cua bdi todn van tdi vdi rang huge khung thdi gian tgi cdc dilm hdng (VRPTW).
- Ap dyng ly thuyet bdi todn vdo thyc te 6% xdy dung cdc hdnh trinh van tdi cho Trung tdm.
Qua phan tich, phuong an de xudt cd hieu qud han so vdi phuong dn hien dang dp dung.
Ngay nhan bdi Idn dau: 28/9/2015 Ngay nhan bai sira: 27/11/2015 Ngdy chap nhSn ddng bai: 30/10/2015
Tai lifu tham khao
[1]. Th.S Trdn Thj Lan Huang (2007), Nhdp mdn Td chuc vgn tdt 6 td, NXB Dai hgc GTVT [2]. TS. Ddng Vu Tiing (2000): Nghien cuu van chuyen thu gom rdc tai Hd Ngi, Xudt ban tren tap tri Nghien cim van hdnh cua Chau Au.
[3]. B.L. Golden (1981), Classification in Vehicle Routing and Scheduling, A'e/woryt//, 97-108.
[4], Savelsberg, M.W.P. (1985), Local Search in Routing Problem with Time Window, Annals of Operations Research 4: 285 - 305.
[5]. Toth, P; Vigo, D. (2001). The Vehicle Routing Problem. Philadelphia: Slam. ISBN 0-89871-579-2.
Phan bi^n; TS. Nguyin Thanh Chirong, TS. Nguyin Thj Phumig.
Tgp chi KHOA HOC GIAO THONG VAN TAI So 49 - 12/2015 109