Information Technology Reference
In-Depth Information
2
Planning Prerequisites and Requirements
A core competence and an important task of a 4PL is the planning, orchestration and
choreography of complex logistics services integrating various subsidiary logistics service
providers [8]. Therefore, different IT-systems are used. Within the design phase, relevant
services have to be identified and liable providers have to be chosen and coordinated in the
overall process. Moreover, the entire structure of the logistics network with regard to their
temporal dependencies has to be validated. Appropriate instruments for this purpose are,
for instance, process modeling languages (e.g. Business Process Model and Notation
(BPMN), Event-driven Process Chain (EPC)). Davenport defines a process as “
a specific
ordering of work activities across time and place, with a beginning, an end, and clearly
identifies input and outputs:
a structure for action
” [9] Processes can be also described as
follows: a process is defined as a coherent, self-contained sequence of activities required
to fulfill an operational task in order to produce a specific service or product [10]. Similar
to this is the description in [11] in which a process is described as a collaboration between
process roles which perform tasks on concrete artifacts. Though processes have been
widely used within a company, the definition above also allows making use of processes
in an inter-company context with the same purpose. Thus, process modeling as an activity
for the definition and description of a process combines executive (organizational units),
design objects (information objects) and tasks (activities) and connects them via different
control flows regardless of organizational boundaries. Fields of application and purpose of
process modeling are, for example, the documentation, preparing for automation or
optimization. As processes are described as a structure for action, process modeling
languages represent the static structure of business processes but the dynamic aspects are
not considered. This leads to a growing use of simulation in logistics [12]. Therefore,
process models are in many cases the basis for building simulation models [13].
Simulation allows the current behavior of a system to be analyzed and understood.
“Simulation is the imitation of the operation of a real-world process or system over
time. […] Simulation is an indispensable problem-solving methodology for the
solution of many real-world problems. Simulation is used to describe and analyze the
behavior of a system, ask what-if questions about the real system, and aid in the
design of real systems. Both existing and conceptual systems can be modeled with
simulation."
[14] In logistics, simulation methodology is becoming increasingly
important for securing the planning, management and monitoring of material,
personnel and information flows [12]. As complex logistics services are established
for a long period of time radical changes during the operation phase are very
expensive and often consume an enormous amount of time [15]. Thus, it is necessary
to anticipate the future behavior of a logistics system prior to its implementation.
Hence, simulation models of logistics networks can be used to improve the decision-
making process in the planning phase. Especially discrete-event simulation (DES) is
appropriate to enhance decision support by analyzing several system configurations,
which differ in structure and behavior [16].
The use of simulation also leads to a number of problems. Building simulation
models requires special training and experience to avoid errors, because it is a
methodology that is learned over time. Furthermore, building simulation models and
their analysis is expensive and consume an enormous amount of time. This can lead to
a non-profitable use of simulation [14]. The use of different models within the
