delivery, respectively. The pickup/delivery time
window of a request specifies the earliest and the
latest time at which the pickup/delivery operation of
the request must be performed in each period. In
addition, each selective request has a period window
which specifies the earliest period and the latest
period between which the request must be served.
Moreover, each selective request is associated with a
profit that is the price for serving the request
provided by a shipper. By considering multiple
periods in CA, the carrier can plan its transportation
operations in advance and in a rolling-horizon way.
A carrier must make two important decisions in its
BGP: Which requests are chosen to bid and serve
within their service period windows and how the
routes are constructed to maximize its total profit.
This leads to a new periodic pickup and delivery
problem with time windows, profits and reserved
requests. According to Wang and Kopfer (2014), the
presented problem is NP-hard and it is impossible to
get an optimal solution for large instances by using a
commercial solver like CPLEX. Hence, a hybrid
approach combined genetic algorithm and simulated
annealing (GASA) is proposed to solve the problem.
The numerical results demonstrate the proposed
algorithm can find a good feasible solution in a
reasonable computation time for large instances.
The rest of the paper is organized as follows.
Section 2 is devoted to literature review. A detailed
description of a mathematical model is given in
Section 3. In section 4, the GASA algorithm is
described. In section 5, detailed numerical results of
solving the model by GASA and CPLEX solver on
instances is presented and compared. The final
section concludes this paper with some remarks for
future research.
2 LITERATURE REVIEW
Collaborative Transportation Management (CTM) is
achieved through the horizontal collaboration
between multiple shippers or carriers by either
sharing transport capacities or transportation orders.
With the collaboration, all actors involved can
improve their profitability by eliminating empty
backhauls and raising vehicle utilization rates (Dai
and Chen, 2011). (D’Amours and Rönnqvist, 2010)
present a survey of previous contributions in the
field of collaborative logistics. Indeed, efficient
utilization of vehicle capacity and reducing the
number of vehicles through carrier collaboration is
noticeable in Less than Truck Load (LTL)
transportation. With this type of collaboration,
operation efficiency will increase (Hernández et al.,
2011). The considered problem in the current paper
is a bid generation problem with multi periods in
collaborative transportation. The bid generation
problem (BGP) which is considered from the
perspective of each carrier is the request selection
problem and a key decision problem for auction-
based decentralized planning approaches in CTP.
(Lee et al., 2007) study the carrier’s optimal BGP in
combinatorial auctions for transportation
procurement in TL (truckload) transportation.
Carriers employ vehicle routing models to identify
sets of lanes to bid for based on the actual routes.
(Buer, 2014) proposes an exact strategy and two
heuristic strategies for bidding on subsets of
requests. The model proposed in this paper is a
multi-period extension of the model proposed in (Li
et al., 2016). Both of them assume the BGP of a
carrier, but the BGP considered in this paper
involves multi periods. There are two interesting
studies in multiple periods BGP: (Wang et al.,
2014), (Lau et al., 2007). In these papers, each
carrier considers multiple periods (days) when it
determines which transportation requests to bid and
serve in each period (day). Moreover, requests open
for bid may span across multiple periods (days).
Other works related to ours include studies on the
Team Orienting Problem (TOP). Multiple vehicle
routing problem with profits is called Team
Orienting Problem (TOP) (Chao et al., 1996) focus
on the TOP by considering multiple tour maximum
collection problem and multiple tour VRP with
profits. (Yu et al., 2010) utilize a simulated
annealing algorithm to solve a capacitated location
routing problem.
3 PROBLEM DESCRIPTION AND
MATHEMATICAL MODEL
In this problem, we consider a carrier who wants to
determine which requests to bid (select) among all
requests open for bid (offered by all carriers) in a
combinatorial auction to maximize its own profit by
solving a bid generation problem. Since the carrier
plans its transportation operations in advance and in
a rolling horizon way as mentioned in the
introduction, this bid generation problem involves
multiple periods. We consider the problem in the
less-than-truck load transportation, where each
transportation request is a pickup and delivery
request with time windows, two types of requests-
reserved requests and selective requests are
involved, and each request is associated with a profit