Logistics-based modeling

Instructor's Guide


intro, objects modeling, simulation, visualization, legacy summary, Q/A, literature
Improvements in business performance and productivity may be achieved by critically examining some of the rules that govern a business process. Business process redesign (BPR) is the generic label for many emerging methodologies aimed at producing these improvements. Re-design implies that the current state of affairs is no longer acceptable and can no longer be refined or evolved.

Despite the importance of qualitative assessments in BPR, as noted in  [Hammer90], for modeling we favor a more quantitative approach for which we provide support by means of a simulation library (BPSIM) based on the logistics-based business modeling method (LBM) presented in  [Gerrits95].


Logistics-based modeling -- criteria for redesign

Product lead time -- time between order and delivery


slide: Logistics-based business models

Logistics-based modeling allows for analysing the time spent in executing a business process. The product lead time is defined as the time that passes between the moment a customer orders a product and the moment a product is delivered. In more detail, we can distinguish between processing time (the time actually worked on a job or operation), queue time (the time a jobs waits for a resource to become available), setup time (the time that passes between the moment a resource becomes available and the moment work on the job is started), wait time (the time that is spent waiting for another job to complete), and transport time (the time that is needed to move a job from a resource at a certain location to a resource at another location).

For a particular model, measurements may be obtained by running a series of simulations. Based on an analysis of the simulation results, alternative models may be proposed. For example, when the setup time for a job is relatively large, combining jobs into a single task for an employee may be more efficient. The LBM method offers a number of primitives, with associated graphic icons, from which a business process model may be constructed as a network of resources connected by transport arcs.


Logistics-based modeling primitives


slide: Logistics-based modeling primitives

The primitive entities offered by LBM are listed in slide lbm-prim. Operations are atomic in the sense that wait time, queue time and transport time may not be part of an operation. Only setup time and process time are part of an operation. Tasks are introduced to allow for a series of jobs or operations to be processed, for example by one employee, in order to reduce the setup time needed. Transport entities represent the time it takes for information to flow from one resource (that is operation or task) to another. Transport implicitly defines the sequential structure of a process. However, duplications of information, and consequently parallel operations, are allowed. In addition to the primitives mentioned above, LBM allows us to characterize organizational units to represent departmental boundaries, external agents to represent opaque information producing or consuming entities, and archives to represent paper-based storage facilities. Also, employees may need additional means to engage in an operation or task.