The document discusses formal methods in software development. Formal methods use mathematical approaches to solve software problems at the requirements, specification, and design levels. They are most applicable to safety-critical software. The lecture covers formal methods, software development lifecycles including waterfall and iterative models, and various "cosmic truths" about requirements engineering and obtaining customer involvement.

1. Formal Methods
Lecture # 1
Umber Noureen Abbas
Lecturer
Department of Computer Science
10/27/2022 Computer Science Department, University of Sahiwal 1

2. Formal Method
Introduction
10/27/2022 Computer Science Department, University of Sahiwal 2

3. Learning Objective
•
What are formal methods in software development?
SDLC
• Waterfall SDLC
Computer Science Department, University of Sahiwal 3
10/27/2022

4. What are formal methods in software
development?
• In software development, formal methods are mathematical
approaches to solving software (and hardware) problems at
the requirements, specification, and design levels. Formal
methods are most likely to be applied to safety-critical or
security-critical software and systems, such as
avionics software.
10/27/2022 Computer Science Department, University of Sahiwal 4

5. SDLC
• Stage 1. Planning and requirement analysis
• Stage 2. Designing project architecture
• Stage 3. Development and programming
• Stage 4. Testing
• Stage 5. Deployment
10/27/2022 Computer Science Department, University of Sahiwal 5

6. Waterfall SDLC
10/27/2022 Computer Science Department, University of Sahiwal 6

7. Iterative Model
10/27/2022 Computer Science Department, University of Sahiwal 7

8. COSMIC TRUTH 1
If you don’t get the
requirements right, it
doesn‘t matter how
well you execute the
rest of the project
10/27/2022 Computer Science Department, University of Sahiwal 8

9. COSMIC TRUTH 2
Customer
involvement is
the most critical
factor in achieving
software quality.
10/27/2022 Computer Science Department, University of Sahiwal 9

10. Obtaining Customer Involvement
 Identify user classes
 Select “product champions”
 Employ the use case technique
 Understand how product will be used
 Scenarios
 operational profile
 Build prototypes
 Agree on customer rights and responsibilities
10/27/2022 Computer Science Department, University of Sahiwal 10

11. COSMIC TRUTH 5
The customer is
not always right.
But the customer
always has a point.
10/27/2022 Computer Science Department, University of Sahiwal 11

12. How can customer not be right?
 Presenting solutions in the guise of requirements
 Not prioritizing requirements
 Not communicating or respecting business rules or constraints
 Not making decisions
 Not accepting the need for tradeoffs
 Demanding impossible commitments
 Not accepting the cost of change
10/27/2022 Computer Science Department, University of Sahiwal 12

13. COSMIC TRUTH 6
The first question an
analyst should ask
about a proposed
new requirement is,
“Is this in scope?”
10/27/2022 Computer Science Department, University of Sahiwal 13

14. Questions
Any Question Please?
You can contact me at: umber@uosahiwal.edu.pk
Your Query will be answered within one working day.
10/27/2022 Computer Science Department, University of Sahiwal 14

15. Thanks
10/27/2022 Computer Science Department, University of Sahiwal 15