Following introduction in chapter1, Chapter2 elaborates the problem, and Chapter3 explores relevant research works involving similar problems and briefs their approach. Chapter4proposes policy for fleet assignment and formulates the mathematical model based on the policy. Chapter5discusses the results of computational experiment of the models formulated in Chapter4. Chapter6concludes the study, offers further recommendations to the company and discusses possible future work.
Chapter 2
Problem Description
This chapter unfolds the problem, and its characteristics, explains the solution characteristics and object-ives. Also, it establishes the research goals and the approach towards achieving it. Lastly, the chapter concludes with defining the scope of the study.
2.1 Problem Introduction
The study involves logistics planning challenge arising out of container distribution problem (CDP) in hin-terland transportation. There is a network of nodes for distribution, with the inland container terminal at Veghel (ITV), being the central node (depot of containers). The ITV aggregates and distributes containers from/to consumption and production centres referred to as clients or customers in the report. Predom-inantly, barges forward (collects) containers to (from) the port terminals. Since VBL employs trucks to transport containers to the port as well, port terminals in Rotterdam and Antwerp are considered as nodes in the network, too. Generally, customers place orders with VBL specifying the address and the time to transport containers to (or from) known as the service location and service deadline of the order. VBL references orders with a unique booking number, container details (like container number, dimensions, type: reefer/regular), customer, service location and deadline. The following sections describes the fleet characteristics, truck routing plans and terminal-operations characteristics description to understand daily trucking plans.
2.1.1 Fleet Characteristics
Every truck in the fleet and the charters are capable of transporting all containers regardless of its type (reefers, regular) and dimensions (20 TEU, 40 TEU). However, the drivers with their ability, license permits and preferences alter the capability of the trucks. The capability of trucks to cover distances is called the radius of operation. Accordingly, fleet classification is as follows:
• Terminal trucks: Drivers with less driving experiences and just graduated from driving college can drive to service locations situated within 5 km radius from ITV. The trucks they drive constitute terminal trucks in the fleet.
• Regional trucks: Experienced drivers either without a permit or prefer to avoid going to ports drive the regional trucks. They serve all service locations except the port terminals.
• Port trucks: Well-experienced drivers with permit and preference to drive to port terminals drive port trucks. Port trucks serve all nodes in the network.
The fleet of trucks (considered as resource in the problem) is homogeneous in capacity and heterogeneous in capability. The charter hires are either of regional or port type. Consequently, orders are classified into the terminal, regional and port orders, depending on where the service location is in the network. Figure
CHAPTER 2. PROBLEM DESCRIPTION
Figure 2.1: Fleet classification in terms of radius of operation
2.1depicts the three types of trucks: port, regional (as REG) and terminal (as TERM). The size of nodes in figure2.1has nothing to do with the container volumes trucked to them from ITV but a mere indication of the node’s geographical size.
2.1.2 Routing Plans
Inland container distribution logistics is a particular case of the Vehicle Routing Problem (VRP). Unlike the classical VRP, where the truck loads cargo and serves multiple locations in a trip, where a trip is defined as the movement of truck originating from a logistic hub (ITV in this case) and may visit multiple customer locations and returns to the hub. Here, the routes (or trips) of a truck are dedicated to serve a single customer and returns to the terminal. So, there is no selection of location is involved in determining the route plans in the container distribution problem (CDP). As distances between the ITV and the serving
Figure 2.2: Routing plans of Trucks at ITV
node is considered as constant, driving duration (of an order) between the nodes and ITV is deterministic.
The time a truck spends at the serving node, known as process duration (of an order), is deterministic as well. Process duration includes loading / unloading the container with contents, waiting time, time for document clearances and gate entry at the serving node. Service duration of the node, i.e. the sum of process duration at the node and twice the driving duration (including the return to ITV) to the node, is a property for a node and is deterministic. Figure2.2illustrates the routing plans of trucks, with ITV as the central node and L1, L2, L3 represents the nodes that the trucks serve (port terminals and customer locations). To explain how one trip is performed, consider a day with terminal operation windows (of 4.00
CHAPTER 2. PROBLEM DESCRIPTION
hrs in the morning to 18.00 hrs in the evening) having order o from customer at L3 (regional order) to deliver a container with deadline of 12.00 noon, driving duration to L3 from ITV is 45 minutes and the order process duration is 30 minutes. Then the latest departure time from terminal for the truck t serving order o is 11.15hr. Total service or trip duration for serving the order lasts for 120 minutes. Since this is a regional order, the serving truck can be of either regional or port type. The truck t has to depart at least by latest departure time to deliver the container on-time. Even if the truck t serves the order violating the deadline it has to be within 18.00hrs the terminal operational window
2.1.3 Terminal-Operations Characteristics
Typically, an operational day consists of a mix of orders with multiple nodes with service duration ranging from 25 minutes to 4 hours. At times, on a day, a customer may request multiple containers, so trucks drive multiple times to the same node as well. Usually, in 2019, ITV has catered to 105 to 115 number of orders on an average day. However, on exceptional days orders could be as high as 150. Terminal has 32 trucks in its fleet for fulfilling container transport requests to customers. To meet demand overflow in trucking containers, terminal hires charters. Generally, in the weeks when the weather conditions are unfavourable for barging, or if there is congestion at the port of Rotterdam, then the terminal hires a higher number of chartered trucks as the demand for trucking container increases. Terminal operations starts at 4.00 hr in the morning and closes by 18.00 hr in the evening. Occasionally, it may start early or extend little more than an hour. So operational window is in the range 14 to 16 hours. The planning aims to serve all orders within the terminal operational window, .