3. OVERVIEW
Example of CASE tool
Problem:
Redesigning this CASE tool
that must has a grid to be
displayed in the design
window
4. Problem Redesigning a Computer-aided software engineering (CASE) tool for editing
software design models that must has a grid to be displayed in the design
window
Description To assist in the positioning of entities on a diagram, the user may turn on a
grid in either centimetres or inches, via an option on the control panel”
A grid helps the user to create a tidy diagram with well-spaced entities.
Function General Functional: that the editing system should provide a grid
Non-functional:
1. giving information about the grid units
2. reliability (whether the grid will be shown)= Mean time to failure,
Probability of unavailability, Rate of failure occurrence
3. in term of its efficiency
Destination
operation
The software design tool or the CASE Tool itself.
Condition User interface requirement show how the grid is switched on and off
by the user
5. We highlighted on Functional requirement which is something the system must perform
1. The grid is switched on and off by the user
2. The grid can be turned on or off via an option in the
control panel
3. The system shall provide appropriate viewers which
only passive grid for the user while running this
software.
4. Provide a grid facility where a matrix of horizontal
and vertical lines provides a background to the user.
5. The grid can be in centimetres or inches
Statements of functional
requirements of the system
6. Assumption of the
system
• Although an active grid, where entities `snap'
to grid lines can be useful, the positioning is
imprecise; the user is the best person to
decide where entities(input) will be
positioned.”
• where the alignment of entities is the user's
responsibility.
7. mathematical statements of the
functional requirements
Based on 1,2,3,4,5 from functional requirement’s statements
From 1
p: the user turns the software on
q: the grid is on
r: the grid is off
If the user turns the software on, then the grid is on
If the user not turns the software on (which means its off), then the grid is off
p → q
~p → r
8. From 2
p: the grid turned on
q: the grid turned off
r: via an option in control panel
If the grid can be turned on or off, then it is via an option in the control panel
From 3
p: the system shall provide appropriate viewers
q: show passive grid for the user while running this software
The system shall provide appropriate viewers which only passive grid for the
user while running this software.
p ᵛ q → r
p → q
9. From 4
p: provide grid facility
q: matrix of horizontal line
s: matrix of vertical line
r: provide a background to the user
To provide a grid facility where a matrix of horizontal and vertical lines, then will
provide a background to the user
From 5
centimeters ᵛ inches → grid
The grid can be in centimetres or inches
p → (q ^ s) →r
10. comments about the translation process from
natural languages statements to mathematical
statements
• Natural language is overlapped with words
and phrases, but they also have consequences
mathematically because they affected the
mathematical structure that modeled the
resulting problem statement.
