2. CONTAINER ROUTING IN LINER SHIPPING
Conventional methods in container routing had 2
deficiencies
1) Satisfy level of service
2) Maritime cabotage.
To overcome we use a operational network
representation of a liner shipping network.
4. Xiamen
Chennai (XM)
(CN)
Hong Kong
(HK)
Colombo
(CB)
Cochin
(CC)
Singapore
(SG)
SHIP ROUTE 1 (SR1) Jakarta
HK(1) -> JK(2) -> SG(3) -> HK (JK)
SHIP ROUTE 2 (SR2)
HK(1) -> XM(2) -> SG(3) -> CB(4) -> SG(5) -> HK
SHIP ROUTE 3 (SR3)
CB(1) -> CN(2) -> CC(3) -> CB
5. CONVENTIONS USED
(O-D) – Origin Destination pair
SR - Service Routes (Ship Routes)
P - Ports
R - Set of routes
Nr - No. of portcalls (port)
Pri - i th portcall (port) on route r .
Ir - (1,2,3,…Nr}
6. REPRESENTATION
A possible container path can be given as
+XM - SR2(2,4) + CB - SR3(1,2) + CN
+XM - Loading at Xiamen.
-SR2 – On ship route2 delivered at Colombo.
+CB – Loading at Colombo.
-SR3 – On ship route3 delivered at Chennai.
+CN – Loading at Chennai.
8. OPERATIONAL NETWORK
(N,A) for O-D pairs where
N - Node Set (set of all nodes + source + sink)
A – Arc Set
Arc Set A := Av U At U Asource U Asink
Av – Voyage Arcs
At – Transshipment Arcs
Asource – Arcs from source node
Asink – Arcs from sink node
9. VOYAGE ARCS
a Є Av can be represented by (r,i)
Voyage arcs are edges between adjacent nodes.
Eg: a voyage arc connecting (r,i) and (r,i+1)
Voyage arcs (r,Nr) is the voyage from node (r,Nr) to
node (r,1) because each ship route forms a loop.
11. TRANSSHIPMENT ARCS
Transshipment nodes are those belonging to two ship
routes.
A Transshipment arc a Є At can be represented by
((r,i),(s,j)) where pri = psj
Containers are transshipped at a port that is present in
two routes.
12. TRANSSHIPMENT ARCS
Hong Kong
Colombo (HK) Xiamen
(CB) (Xm)
Singapore Jakarta
(SG) (JK)
SHIP ROUTE 1 (SR1) SHIP ROUTE 2 (SR2)
HK(1) -> JK(2) -> SG(3) -> HK HK(1) -> XM(2) -> SG(3) -> CB(4) -> SG(5) -> HK
Colombo (CB) to Jakarta (JK) : CB -> SG -> HK -> JK
Transshipment : Hong Kong (HK) ( SR2(1) and SR1(1) )
Hong Kong : P 11 = P21 ie Pri = psj
13. TIME AND COST
Each arc a has time duration denoted by ta .
For voyage time is calculated by ,
ta = t r2 – tr1
For transshipment time is calculated by considering
the dwell time in a particular port.
Similarly each arc a has a associated cost given by ca
14. OBJECTIVE
Xa Є {0,1}, a Є A.
Xa is 1 only if there exist a path in the network
OBJECTIVE : Minimize the total cost
minxa ∑ aЄA CaXa
where Xa represent a container path
Ca represent the cost
15. CONSTRAINTS
All paths from the source and sink are considered to be 1 .
Flow conservation:
∑aЄAsource xa = 1
∑aЄAsink xa = 1
16. Cont’d...
Containers never visit their origin port from other ports.
X(r,i-1) = 0 rЄR , I Є Ir , pri = origin
Containers never go from their destination to other ports.
X(r,i) = 0 rЄR , I Є Ir , pri = destination
Containers are never transshipped at origin or
destination port.
X((r,i),(s,j)) = 0 ((r,i),(s,j)) Є Aot U Adt
17. Cont’d…
If the liner shipping company is subject to the maritime
cabotage restriction in the country of the origin port, then it
cannot transship the containers at that port.
X((r,i),(s,j)) = 0 , p Є PѲo ,((r,i),(s,j)) Є Apt
Similarly, if there is restriction in the country of the
destination port,
X((r,i),(s,j)) = 0 , p Є PѲd ,((r,i),(s,j)) Є Apt
18. Cont’d...
The transit time cannot exceed maximum allowable transit
time Tod
∑aЄAvU At taxa ≤ Tod
The total cost cannot be larger than maximum allowable
cost.
∑aЄA Caxa ≤ Cod
19. SUMMARY
The above model is an integer(binary) linear
programming model.
This model can easily capture the various container
paths and obtain all paths that satisfy the constraints.