1. VCE IT Theory Slideshows
Problem Solving Methodology 1
Analysis
By Mark Kelly
Vceit.com

2. Contents Activities Purpose Scope Constraints
Software Requirements Specification (SD)

3. Analysis Investigates the problem before attempting to solve it.
Observe the existing system before doing anything else
Like a doctor examines you before prescribing pills or surgery

4. Observing Measure the system’s performance Interview users
Refer to system logs (e.g. errors, complaints, repairs)
Examine system’s output

5. First question to ask Is there really a problem?
Sometimes, there is no problem: that’s the best the system can do
E.g. your home wireless network is not reaching the claimed 54Mbps transfer speed mentioned on the box
Not a problem: that’s only a theoretical maximum which is never likely to be actually achieved.

6. Don’t bother Can’t solve problems that don’t actually exist
But you can waste a lot of time and money trying.

7. Second question Can it be fixed? Technical feasibility
Some problems cannot be fixed, e.g. a horse’s broken leg.
Pointless to even try.
Don’t waste time and money on a hopeless cause.

8. Third question Is it worth fixing? Economic feasibility
Some problems are not worth the necessary time, money and effort
You can maybe get a pushbike to do 150km/h but surely it’s easier to get a motorbike instead?

9. And more questions
Legal feasibility – can you fix it without breaking any laws?
Operational feasibility – if you fix it, do you have the staffing, equipment, skill base, money etc to continue to operate it?

10. Scope of the solution What can the solution do?
What can't the solution do?
The boundaries or parameters of the solution.
How will the solution benefit the user?

11. Get the scope right – avoid feature-creep and cutbacks

12. Constraints
What conditions need to be considered when designing a solution? E.g.
cost,
speed of processing,
requirements of users,
legal requirements,
security,
compatibility,
level of expertise,
capacity,
availability of equipment

13. If the answers are not all “YES”
GIVE UP
Cancel the project
Better to give up now than to proceed and waste far more time and money on a doomed project.

14. Determine solution requirements
What information does the solution have to provide?
What data is needed to produce the information?
What functions does the solution have to provide?

15. Solution Requirements
Put into a logical design.
Lays down the specifications of the new or modified system.
Specifies what it should be able to achieve.

16. Logical Design Like a “wish list” of features
Only lists specifications, e.g. “should be able to produce 20,000 invoices in 2 hours with 99.9% accuracy”

17. But
The logical design does not attempt to say how these objectives will be achieved.
Don’t jump to conclusions about what software, hardware etc will be needed.
Just define what you want it to do.

18. These requirements can be
Functional - what the solution is required to do
Non-functional, which attributes the solution should possess, such as
user-friendliness,
reliability,
portability,
robustness,
maintainability.

19. Remember
You should be able to start a functional requirement with “It should be able to…”
E.g. “It should be able to calculate annual salary”
You should be able to start a non-functional requirement with “It should be …”
E.g. “It should be portable/secure/fun to use”

20. Tools
Logical design tools to assist in determining the solution requirements include ...
context diagrams,
data flow diagrams and
use case diagrams
Logical Data Dictionaries (e.g. “What data should be in a sales contract?
Hierarchy Charts / Organisational chart
Decision Trees

21. If all the answers are “YES”...
All data collected during analysis needs to be documented for later reference.
Each step in the PSM must be fully and properly finished before the next step begins

22. Finally
The client, or boss, gives approval to move onto the next step: design

23. VCE IT THEORY SLIDESHOWS
By Mark Kelly
McKinnon Secondary College
vceit.com
These slideshows may be freely used, modified or distributed by teachers and students anywhere on the planet (but not elsewhere).
They may NOT be sold.
They must NOT be redistributed if you modify them.