6.3 Suspended Ceiling Design Process - Bilkent University

There are several limitations in this type of modeling such as the
following (Shi and Deng, 2000):
1. They lack the ability to model feedback and iteration in the
projects, so that they cannot model projects as a dynamic
decision process.
2. They deal with an activity as a non-stop process. However, in
practice activities may be interrupted when required
conditions cannot be met.
3. They can be time-consuming to prepare, difficult to read and
to update.
Pultar (1990) has developed a progress-based scheduling technique
based on progress charts and bar charts to overcome the problem of
fragmentation of activities during the application of the conventional
CPM to construction projects. CPM type of modeling has been used in
many construction projects with varying degrees of success. However,
the technique has remained to be useful for the construction phase of
building process rather than the design phase.
3.2.1.2 Petri Nets
A more recent process model of design that describes information flows
is a Petri net model. A Petri net is a graphical modeling tool that
consists of places, transitions, and arcs (Figure 3.3). Basically, it defines
transitions that are interpreted as activities, and tokens that are
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