Example: Analysis of a PERT-Type Network.
It is described in different sources [1, 2]. So, this is chapter 14 of [2] and section 7.11 of [1].
PERT is a technique for evaluating and reviewing a project consisting of
interdependent activities. A number of books have been written that describe
PERT modeling and analysis procedures. A PERT network activity descriptions
are given in a table stated below. All activity times will be assumed to be
triangularly distributed. For ease of description, activities have been
aggregated. The activities relate to power units, instrumentation, and
a new assembly and involve standard types of operations.
In the following description of the project, activity numbers are given
in parentheses. At the beginning of the project, three parallel activities
can be performed that involve: the disassembly of power units and
instrumentation (1); the installation of a new assembly (2); and
the preparation for a retrofit check (3). Cleaning, inspecting, and
repairing the power units (4) and calibrating the instrumentation (5)
can be done only after the power units and instrumentation have been
disassembled. Thus, activities 4 and 5 must follow activity 1 in the network.
Following the installation of the new assembly (2) and after the instrumentation
have been calibrated (5), a check of interfaces (6) and a check of
the new assembly (7) can be made. The retrofit check (9) can be made
after the assembly is checked (7) and the preparation for the retrofit
check (3) has been completed. The assembly and test of power units (8)
can be performed following the cleaning and maintenance of power units (4).
The project is considered completed when all nine activities are completed.
Since activities 6, 8, and 9 require the other activities to precede them,
their completion signifies the end of the project. This is indicated on
the network by having activities 6, 8, and 9 incident to node 6, the sink
node for the project. The objective of this example is to illustrate
the procedures for using Aivika to model and simulate project planning network.
Activity Description Mode Minimum Maximum Average
1 Disassemble power units and instrumentation 3 1 5 3
2 Install new assembly 6 3 9 6
3 Prepare for retrofit check 13 10 19 14
4 Clean, inspect, and repair power units 9 3 12 8
5 Calibrate instrumentation 3 1 8 4
6 Check interfaces 9 8 16 11
7 Check assembly 7 4 13 8
8 Assemble and test power units 6 3 9 6
9 Retrofit check 3 1 8 4
Node Depends of Activities
1 -
2 1
3 2, 5
4 3, 7
5 4
6 6, 8, 9
Activity Depends on Node
1 1
2 1
3 1
4 2
5 2
6 3
7 3
8 5
9 4
[1] A. Alan B. Pritsker, Simulation with Visual SLAM and AweSim, 2nd ed.
[2] Труб И.И., Объектно-ориентированное моделирование на C++: Учебный курс. - СПб.: Питер, 2006