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SOFTWARE ENGINEERING
1. [5 marks] Software Project Failure
Find an example of a significant software project failure. (Hint: use a Google search with something like “software project failure”.) Assume “significant” means greater than $30 million US/Australian dollars or equivalent.
(a) [3 marks] In your own words, describe the project and its failure circumstances. The description should be at least 200 words but no greater than 500 words.
Cite your sources of information (At least one web URL or book/journal citation is acceptable).
(b) [2 marks] What do you think are the (2) major reasons why the project failed?
(Write one sentence or short paragraph for each.)
2. [5 marks] The Waterfall model
Answer the following parts in your own words, i.e. do not copy or quote, but paraphrase.
(a) [1 mark] Describe in your own words each phase of the waterfall model in about two to four sentences.
(b) [2 marks] Consider a scenario where the requirements were thought to have been finalised but during the design phase it became clear that part of the requirements were wrong.
Dealing with this situation would be quite difficult if the project was being implemented using the waterfall model as depicted in Figure 2.1 of the Sommerville text.
i. [1 mark] What is the problem with the waterfall model definition in Figure 2.1?
ii. [1 mark] What changes need to be made to that diagram in order to enable a sensible course of action in our scenario?
(c) [1 mark] Explain the advantages of the waterfall method in three to five sentences.
Give at least one example where the waterfall model is appropriate.
(d) [1 mark] Summarise the advantages of incremental delivery in about 3 to 5 sentences of your own words. Give at least one example where the waterfall model is inappropriate.
3. [10 marks] Project Scheduling
A project requires the tasks shown in the table below to be completed. The duration column shows the number of weeks estimated for one person to complete the task.
Task
Duration
(weeks)
Depends on
T1
1
2
T2
3
T3
5
T4
3
T1
T5
2
T1
T6
2
T1,T3
T7
1
T2,T3
T8
3
T4,T5,T6
T9
3
T5,T7
T10
2
T7
T11
2
T8
T12
3
T8,T9
T13
2
T10
Answer the following questions.
Diagrams may be produced in a number of ways, as long as the result is a PDF file for submission.
The activity diagram could be produced using a drawing program while the bar chart is probably easier to create using a spreadsheet application. For instance you could
use a spreadsheet as a graphical display where columns indicate weeks use one row per task; multiple horizontal cells represent tasks (with appropriate use of cell merge, borders, background colour)
use the bar charting capability of a spreadsheet program1.
Questions:
(a) [1 mark] Draw an activity network. Show a Start and Finish “activity” (These are zero length pseudo-activities).
(b) Assume one person works on each task. (That is: use the durations in the task listtable.) Answer the following questions:
i. [2 marks] Draw a bar chart (Gantt chart), showing the earliest start and finish times for each task.
ii. [1 mark] List or otherwise indicate the tasks on the critical path, and compute its length.
iii. [2 marks] For each non-critical task, how many weeks may its start be delayed without affecting the finish time of the project.
(c) [2 marks] Assume 4 engineers, Bill, Sue, Mary and Frank, work on the project and that each task is worked on by one engineer only. Allocate tasks to them to complete the project in the shortest possible time. Show this graphically on a staff allocation chart.
The sum of task durations is 32 weeks which when divided by 4 engineers gives a value of 8 weeks, which one might expect to be the minimum time to complete the project. Explain why it is not possible to complete the project in 8 weeks.
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(d) [2 marks] Now consider a different way of assigning work to the project. Assume that the same 4 engineers as before but that tasks of length 2 weeks or more can be worked upon by either one or two engineers. If two engineers work in a task their individual effort must add to the listed total duration, but each must do at least one week of work.
Allocate tasks to complete the project as soon as possible. Show this graphically on a staff allocation chart.
