Activity on edge (ace) network write a c/c++ program that allows the user to input an aoe network. Assume activity iis repres
Answers
To remind you of the problem we considered before it was a small project that consisted of 11 activities (as below):
Activity Completion
number time (weeks)
1 Redesign product 6
2 Redesign packaging 2
3 Order and receive components for redesigned product 3
4 Order and receive material for redesigned packaging 2
5 Assemble products 4
6 Make up packaging 1
7 Package redesigned product 1
8 Test market redesigned product 6
9 Revise redesigned product 3
10 Revise redesigned packaging 1
11 Present results to the Board 1
with the following list of immediate precedence relationships:
Activity Activity
number number
1 must be finished before 3 can start
2 4
3 5
4 6
5,6 7
7 8
8 9
8 10
9,10 11
In the network diagram shown below which represents this project, each arc represents an activity and is labelled with the activity number and the associated completion time (shown in brackets after the activity number). This network is an activity on arc (AOA) network. The nodes of the network represent the start (and end) of activities and are regarded as events.
In constructing the network we use the precedence relationships to construct it from left to right - adding activities (arcs) to the network as the precedence relationships indicate that activities can start.
The key to constructing the network is the question: "What activities can start now?"
Initially, for example, both activities 1 and 2 can start. Once activity 1 has been finished activity 3 can start, once activity 2 has been finished activity 4 can start, etc. The nodes of the network are numbered 1,2,3,...,etc. Note:
that all arcs have arrows attached to them (indicating the direction the project is flowing in)
the way the relationship "activities 5 and 6 must be finished before activity 7 can start" is represented
The diagram below illustrates the kinds of situation we can represent in network diagrams.
In the last situation shown above we have a dotted arc. This dotted arc is a dummy activity. Dummy activities often have a zero completion time and are used to represent precedence relationships that cannot be easily (if at all) represented using the actual activities involved in the project. By convention dummies are always shown as dotted arcs in network diagrams.
Note the difference between the last two situations shown above. The difference between them is that in one C must be finished before B can start, and in the other there is no relationship between C finishing and B starting.
Suppose that we had included in our list of precedence relationships "activity 3 must be finished before activity 8 can start" - then the easiest way to represent this on the network diagram is by having a dummy activity, with a zero completion time, directed from node 3 (the end of activity 3) to node 7 (the start of activity 8).
Dummy activities can have a non-zero completion time, e.g. if (taking the example mentioned in the previous paragraph) there must be a two week delay between finishing activity 3 and starting activity 8.
Often in drawing large networks we find that the easiest way to represent some precedence relationships is by dummy activities. Note here however that in AOA networks there is often more than one way to correctly represent the network logic using dummies. Note too that the key to drawing dummies to to
ensure that they correctly represent the logic you want; but also that
they do not introduce unintended consequences (introduce precedence restrictions that you do not want)