OVERVIEWExample of CASE toolProblem:Redesigning this CASE toolthat must has a grid to bedisplayed in the designwindow
Problem Redesigning a Computer-aided software engineering (CASE) tool for editingsoftware design models that must has a grid to be displayed in the designwindowDescription To assist in the positioning of entities on a diagram, the user may turn on agrid 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 gridNon-functional:1. giving information about the grid units2. reliability (whether the grid will be shown)= Mean time to failure,Probability of unavailability, Rate of failure occurrence3. in term of its efficiencyDestinationoperationThe software design tool or the CASE Tool itself.Condition User interface requirement show how the grid is switched on and offby the user
We highlighted on Functional requirement which is something the system must perform1. The grid is switched on and off by the user2. The grid can be turned on or off via an option in thecontrol panel3. The system shall provide appropriate viewers whichonly passive grid for the user while running thissoftware.4. Provide a grid facility where a matrix of horizontaland vertical lines provides a background to the user.5. The grid can be in centimetres or inchesStatements of functionalrequirements of the system
Assumption of thesystem• Although an active grid, where entities `snapto grid lines can be useful, the positioning isimprecise; the user is the best person todecide where entities(input) will bepositioned.”• where the alignment of entities is the usersresponsibility.
mathematical statements of thefunctional requirementsBased on 1,2,3,4,5 from functional requirement’s statementsFrom 1p: the user turns the software onq: the grid is onr: the grid is offIf the user turns the software on, then the grid is onIf the user not turns the software on (which means its off), then the grid is offp → q~p → r
From 2p: the grid turned onq: the grid turned offr: via an option in control panelIf the grid can be turned on or off, then it is via an option in the control panelFrom 3p: the system shall provide appropriate viewersq: show passive grid for the user while running this softwareThe system shall provide appropriate viewers which only passive grid for theuser while running this software.p ᵛ q → rp → q
From 4p: provide grid facilityq: matrix of horizontal lines: matrix of vertical liner: provide a background to the userTo provide a grid facility where a matrix of horizontal and vertical lines, then willprovide a background to the userFrom 5centimeters ᵛ inches → gridThe grid can be in centimetres or inchesp → (q ^ s) →r
comments about the translation process fromnatural languages statements to mathematicalstatements• Natural language is overlapped with wordsand phrases, but they also have consequencesmathematically because they affected themathematical structure that modeled theresulting problem statement.