KHOA H Q C - CONG NGHE Tap Chi GTVT 7/2012
NHUfNG VAN DE CUA DICH VU KIEM SOAT LUU THONG Dl/OfNG THUY CVTS) DOI VOfJ MOT HE THONG CU THE
T.S LE V A N TY Trudng Dal hoc GTVT TP. Ho Chi Minh
Tom tal: Viec khai thac hieu qui hi thdng dich vu kiim soat lUu thong thiiy (VTS) vUa lap dat tai luong VungTiu - Sai Gdn phu thupc vio nang lUc cua cic sy quan dieu hanh. Hg phai quan tim dung mffc tdt cic van de cua hi thdng va dieu kiin cu the ciJa luong.
Abstract A new system of Vessel Traffic Service (VTS) has been installed on the channel Vung Tau - Sai Gon. It's effective service will depend on the pro- fessional ability of VTS's officers who should care ad- equately about problems of system with condition of the area.
1. N g u y e n t a c h o a t d o n g c d bSn c u a he t h d n g VTS
Muc tidu cd b&n ciia he thdng VTS la hd trd thdng tin va hudng dan cho tau thuyen trong lue hanh trinh va td ChQc lUu thfing nham nang cao tinh an toan va hieu qui trong giao thfing dQdng thiiy, tranh phat sinh cac tinh hufing nguy h i l m . Trong khi khfing lam thay ddi quyen han va trach nhiem ciia cac thuyen trudng tren tau theo quy dinh cua Quy tic qudc te ve phong ngUa va cham, 1972. T h u y l n trufing phai tuan theo cac quy djnh va hufing dan cua cd quan quan ly he thdng. Hoa lieu la ngufii b i l t rfi ve vung hoat dgng cua he thdng VTS vi t h i ddng vai trd rat quan trgng trong liSn lac cung nhu cac quy trinh thuc hien
Trdn the gifii he thdng VTS da dugc nang cap thanh he thdng VTIS (Vessel Traffic and Information Service) la do chQc nang cua nfi khfing eh? eung cap thdng tin cho tau t h u y l n ma cdn phuc vu cho cac ben hen quan d i n hoat ddng hang hai frong khu vQc nhu hoat ddng c u a cac c a n g , hoat ddng djch vu„.
(Singapore). Hoac d t h i he thQ 3 la VTMIS (Vessel Traffic Management and Information Service), VTMIS bao quat cac hoat ddng trong khu vQc nhQ:
Thfing bao, iQu g i d , phan phdi, quan ly thfing tin, hufing dSn cac hoat ddng hang h^i, cQu nan va bao ve moi trudng.
V l nguyen ly, nhan vien dieu hanh VTS s d d y n g may tinh va radar hien dai d l cfi dupc toan canh cua khu vuc tren h^i dd dien t d , xac djnh mdt nguy h i l m / I hang hai, cung cap thdng tin, k h u y i n cao hay lUfing dan de danh lai nhQng vung nufic trdng va an gan cho tau khac. Tuy nhien viec dieu dpng con tau a m d l van de phUc tap phu thufic vao tinh nang : h u y l n dfing c i i a chung va ngoai canh tac dpng.,,
^hOng thong tin chuyen d i n tau tdt nhat la k h u y i n
;ao va can phai rd rang d l t h u y l n trufing cd f h l h i l u :hung mpt each nhanh chdng.
Du trach nhidm dSn tau an toan cudi cung v i n i d t h u y l n trudng nhung d l dat hieu qua chung thi l o t phan trach nhiem dupc chia cho ca V T S .
Ve c l u true ciia he thong VTS cfi f h l cd 2, 3 hoac
mgt sd vung (Sector), tuy thudc ludng hang hiu va kha nang bao phii ciia eac t h i l t bi, sao eho viec theo ddi dupc lien tyc va hinh anh luu thfing cua cac phUPng tien dUPc rd net nhat.
Trong cdng tac td chUc dieu hanh cfi 3 phuong phap phan chia.
Hinhl.Tgi mgt Trung tim cua he thdng VTS a. Phan chia theo khu vUc dia ly: La phan cac ddng luu thdng bang each lap nen cac he thdng phan ludng, quy djnh cac khu neo dau, cae khu vUc danh de tau thuyen bang qua trong khi luu thong
b Phan chia theo thdi gian: Giong nhd mot phan cua ke hoach hanh trinh da dUdc thfia thuan giQa cae ben. Mdt eon tau se dUPc sQ dyng mfit khu vQc hoac mdt tuyen hanh trinh nao dd trong mdt khoang thdl gian da dugc dmh trudc.
c, Phan khoang each chay tiu: Cac tau phai giQ khoang each toi thieu tfii tau khac.
Ddi tugng ciia he thdng VTS, thudng dUdc chia ra 2 loai,
a, Dii tffdng bit bupc tham gia hi thd'ng VTS: Cac ddi tuong nay cd nghTa vy phai bao cao, gid lien lac qua kenh trUc VHP va di c h u y i n theo quy trinh da thong bao.
b. Ddi tffdng khdng bat budc tham gia la nhQng phuong tien khfing thudc quy dinh tren nhUng phai tuan thil quy tac giao thfing, trQc kenh VHP cua VTS va khi can phai gpi d l dUpc hufing dan.
2. Dp t i n cay ciJa t h i e t b j : Hieu qua thuc hien cua thief bj phu thufic rat Ifin vao cac djch vy dupc cung cap, quy dinh bdi "khoang Thfii gian trung binh giQa cac l^n may bi su c d " ( Mean Time Between Failures - MTBF) va kha nang s d dung cac dich v u , Theo lALA, mdt he thdng tdt yeu cau hieu qua dat 99,9%
hoac cao hdn (sQ c6 it hPn 9 gifi mdi nam) Cac nha s^n xuat phai cung cap ban danh gia v l do tin cay ciia trang thiet bi dUa tren cdng thUc cfi the dupc s d dung sau:
MTBF
A., MTBF + MTTR
{1)II
KHOA H Q C - C O N G NGHEHinh 5. Dg rung dgng cua dgng ca d tdc dg 3000vg/ph, 100% tai, vdi ty lg LPG khae nhau
6 ty le LPG 30%, bien dfi rung ddng Ifin nhat ciia ddng co A KAcc cting giam mdt it so vfii trufing hpp thay the 20% diesel va cao hdn so vdi trUfing hpp sQ dung ddn nhien lieu diesel la 125%. Tuy nhien frong trudng hdp nay lai xuat hien cd nhieu bien dd rung ddng cfi fan sd Ifin hpn so vdi trufing hop ty le LPG 20%. T i l n g gfi do kich nd xay ra manh,
Vfil ty le LPG bang 4 0 % bien dp rung ddng Ifin nhat ciia ddng cd A KAcc cao hpn 183,3%. Ddng cd xay ra tieng gd manh Met Day cung la ly do ma khdng the thuc hien viec tang IUdng LPG t i l p theo cho ddnp cd.
4. Ket luan va phUOng hUdng p h a t t r i e n He thdng dieu khien cung cap LPG dQdc t h i l t k l cd kha nang dam bao cho dfing co hoat ddng dn djnh fi tat ca cac che dd lam viec. Vdi ket qui thQ nghiem tren dufing dae tinh ngoai cho thay cfi t h i Qng dung LPG tren dfing cd diesel vfii ty le 30%, fi tdc dp tliap cd t h i thay the tfii 40%, tuy nhien khi ty Ie LPG cang tang len thi hien tupng kich no cang de xay ra Vfii ty le thay the LPG len tfii 30% deu cho lupng tieu thu nhien lieu diesel+LPG nhfi hpn khi sQ dyng ddn nhien lieu diesel, Ddng thfii dp rung ddng eua dfing cP cung tang len khi tang ty le LPG do tdc do tang ap suat ldn va hien IQpng kicfi nd.
Trong nghien cQu nay, bd ELC dUdc dieu khien thil cdng thfing qua giao dien k i t ndi vdi may tinh
frong khi dfing co thQ nghiem la ddng cd trang bj hg thfi'ng nhien lieu diesel d i l u k h i l n dien t d . Vi vgy, trong tUong lai can cd de tai nghien cUu bfi dieu khien cung cap LPG ( ELC) tU dfing giao t i l p vfii ECU dong CO theo IQng c h l dfi lam viec •
Tai lieu t h a m khSo
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[2]. Tong cdng ty xang ddu Uldl Nam, LPG-Bdc linh LPG, Ha Ndl, 1997.
[3]. Blackmep Davep Cdmpaiiy, Liqullled gag handbodk, Buleitli 500- 01,2008.
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[5]. Thdi hdo Kinh le Sai Gnn, Cdu Long se cd I.SOO taxi chay b i i i khi LPG, 29/10/2010.
[ 6 ] . Ngoyio Qoang Vinh. Nghien cilo sd dung khi hda Idig cha l e kiyt vi mac dich bao ve mdi trtfdng. Gdng ty cd ktil Ngd Gia Tif, 2008.
[7]. TS. Pham Hdu Tuy^n, PGS.TS it Anh Tuan, KS. Nguygn The Tpdc, KS. Uu Ktidc Thign (2011), Nghidn cdu su* dung Iddng nhien lieu LPG/diesil tpen ddng cd diesel, Tap chi Giao Ih5ng van lal sn l+Z/ZOIl, ISSN 086B- 7012.
[8]. Thumas Henald C.J, Snmasoodapam P. Expepimeolal lovesilgatloi on Aitenuation of Emission with Dpilmlzed LPG Jel lodocllon m a dual Fuel Biesel Engine and Ppedictlon by ANN Model. Enepgy PPdcedia 14 (2012) 1427-1438
[9]. AVL GmbH, Single cyHuttop peseapch engine 5402, AnsiPla (2001).
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[11]. Ld Phddng lan, Hoang Ode K^l (2000), Gian tPidh ly thuyel & hal lap Bopland DELPHI, NXB Giad doc
[12]. Ngd Bleo Tap (2003), Ky Ihudl vl dl^d hhiea vdi AVR, NXB Khoa hoc va ky iftoat
[13]. Ngnyin Tddng Vi, PGS.TS. Ld Anh Toan, PBS.TS. Hoang Binh Loag, Ngoyio The Tpiic, Vu Khdc Thien (Sd dac biel Ihang 10/2011), Nghien cdu dac tinh cua ddng cd diesel mdt xilanh khi sd dung lifdng nhien lien LPG/diesel, Tap chi Cd k h l .
PHIflfNG PHAP PHAN TJCH...
(Tiip theo trang 29) Bieu 2. Bang phin tich chi phi thue ngodi mdy thi cdng
T I l ^ H g
1 2
4
p C f i i i g
L D T T U I 1 100 1 c o o 1 i 5 0 0 0 0 O'iO 5 0 0 5 , 8 0 0
! < ) Q I O J S U 2 0 . 150.000 32 123 'ISO 2 i % 7 ' « M70 2 7 , 8 X 1 , 1 2 0 1 ' 2S0 0 0 0 KAA-m-'JO
-,
t i 0 1 1 275 0 0 0 2*1.150.003.000 H t O C r t T ' i O O 2 1 1 L1 7fy 0 0 0 2 0 . I 7 O , ( . 1 1 . 0 0 0
7 1.2 S 0 0 0 . 0 0 0 1 6 J , 0 4 L J 2 9 , 5 0 0
r
1,210,000 1 0 0 0 0 0 0 1,322 5 0 0 a 1 0 , 0 0 0
< J 0 2 5 0 0 2 5 0 ^ 0 0 5 . ' W i O 0 O
Ap dung phudng phap hdi quy t u y l n tinh d l xac dinh chl phi may thi cfing theo sd ngay cfing lao ddng trUctiep: Y - a + b , X
Vdl Y la tdng chi phi may thi cdng, X sd ngay cdng lao dfing trpc t i l p .
Ap dung phuPng phap tdng binh phUdng sai sd nho nhat, tim tham sd a ya ID thdng qua thiel lap va giai he phuong trinh chuan t&c,
6a + 5.800 b - 161 494,690
5,800a + 5.995,000 b = 164.041,329.500 Giai he phUdng trinh tren vfii k i t qua:
a = 7,176,376 (ddng) , b - 20,420,08 (ddng/ngay)
PhUdng trinh dU doan chi phi thue ngoai may thi cdng fi Cdng ty se la'
Y - 7,176,376 + 20.420.08.X
Gia sQ, quy mfi san xuat eua doanh nghiep dugc dac trung bdi chi tieu sd ngay cdng lao ddng true t i l p trong ky (thang 7) la 1.000 ngay cdng. Nhu vay, ap dyng mfi hinh hdi quy tren, tdng chi phi may thi cdng se la:
Y = 7 176.376 + 20.420,08x 1.000 = 27,590 450 3. K i t luan
PhUdng phap tong binh phQdng sai so nho nhat dugc cac nha qu^n tri DN sQ dyng nhU mdt cdng cu rat phd bien trong viec phan tich chi phi hdn hpp vi tinh uu Viet ciia nfi dfi la mang lai k i t qua tUdng do'i ehinh xac, qua dfi se phue vu eho nha quan trj doanh nghiep xac dinh dung d i n phUdng hufing de nang eao hieu qua ciia chi phi, Tuy nhien, phUPng phap nay cung tdn tai khd khan nhu- Viec thu thap, xQ ly sd heu cho viec tinh toan va danh gia mat thfii gian va cfing sdc. Viec phan tich chi phi hdn hdp thanh yeu td^biln phi va dinh phi can sQ dung phUdng phap n^ay de j h u c hien, nd d^m bao tinh chinh xac va tinh tong the cao 3
Tai l i e u t h a m k h a o
[1]. PGS. TS Vd Van Nhi (2009), Ke toan DN xay lap - Ke toin don vt chiJ dau tu\ NXB Tai chinh
[2]. PGS.TS Doan Xuan Tien (2005), Giio trinh ke toin quan tn DN, NXB Tai chinh
[3], Bang tdng hpp chi phi nam 2 0 1 1 - Cdnq tv CP dau tu va xay dung PML Viet Nam
