1. Introduction to Software Engineering
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Introduction to Software Engineering
Yaodong Bi, Ph.D.
Department of Computer Sciences
University of Scranton
September 22, 2018

2. What is Software Engineering
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What is Software Engineering
The application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software.
The study of approaches as in (1).
by IEEE Computer Society
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3. Knowledge Areas Software requirements Software design
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Knowledge Areas
Software requirements
Software design
Software construction
Software testing
Software maintenance
Software configuration management
Software engineering management
Software engineering process
Software engineering tools and methods
Software quality

4. Related Disciplines Computer Science Computer engineering Management
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Related Disciplines
Computer Science
Computer engineering
Management
Mathematics
Project Management
Quality Management
Software Ergonomics
Systems Engineering

5. Well-Engineered Software
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Well-Engineered Software
Maintainable
Changes can be made without undue costs
Reliable
Behave consistently in a user-accepted manner
Efficient
Not make wasteful use of system resources
Friendly user interface
Easy to learn and use

6. Software Process
A framework for the tasks that are required to build high-quality software
A process defines who is doing what, when and how to reach a certain goal
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7. Generic Activities Construction
Communication - Communication with stakeholders and encompasses requirement gathering and other activities
Planning - Establishment of a plan: technical tasks, risks, artifacts, work schedule
Modeling
Analysis – better understanding of requirements
Design – that achieves the requirements
Construction
Code generation
Testing
Deployment - Delivery of software for customer evaluation

8. Generic Activities Construction
Communication - Communication with stakeholders and encompasses requirement gathering and other activities
Planning - Establishment of a plan: technical tasks, risks, artifacts, work schedule
Modeling
Analysis – better understanding of requirements
Design – that achieves the requirements
Construction
Code generation
Testing
Deployment - Delivery of software for customer evaluation

9. Waterfall Model Requirements Design Code Test Integrate & Package
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Waterfall Model
Requirements
Design
Code
Test
Integrate & Package

10. Waterfall model Oldest known process model
A systematic, sequential approach to software development
The output from each step is the input of the next step
Complete requirements must be specified in the first step
The final product is not delivered to the customer until all the first four steps are completed.
Drawbacks:
Real projects normally do not follow the sequential order
It is very hard for the customer to specify the requirements
A working system will not be seen by the customer for a long time
Requirement error may not be found until the system is delivered – which is very very costly to fix.

11. Incremental Model time Requirements Requirements Requirements Design
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Incremental Model
time
Requirements 1
Requirements 2
Requirements N
Design
Design
Design
Code
Code
Code
Test
Test
Test
Deliver 1st increment
Deliver 2nd increment
Deliver Nth increment

12. Incremental model The waterfall model applied in an iterative fashion
Each linear sequence produces an increment to the system
Normally a core product is delivered, then additional features are incrementally added
Useful when staffing is lacking
Help in managing risks
Difficulties:
Decomposing a system into independent, implementable components is not easy
Overlapping the different increments due to sequential dependencies of information.

13. Rapid Prototyping Model
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Rapid Prototyping Model

14. Rapid Prototyping Model
Assist the software developers and the customer to better understand the requirements
“I know that is what I asked, but it isn’t what I wanted.”
A quick, dirty prototype is used by the developer and customer to understand and refine the requirements
Rarely employed for complete development cycle
Drawbacks:
The customer may perceive the prototype as a working system
Assumptions and the architecture of the prototype may influence the architecture of the real system

15. 9/22/2018
Spiral Model

16. Spiral Model
Risk-driven approach – before starting each phase, an attempt is made to control or resolve the risks 
Prototyping and modeling are integral part of the process
A cyclic approach for incrementally growing a system’s degree of definition and implementation
In each cycle all stakeholders review all products and objectives so that all are committed to the project
Useful for large-scale and requirements fuzzy systems

17. The Rational Unified Model
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The Rational Unified Model

18. The Rational Unified Model
Four phases of the process
Inception – establish a business case for the system
Elaboration – Develop an understanding of the problem domain, establish an architectural framework, , develop the project plan, and identify key project risks
Construction – Involves system design, programming and testing
Transition – move the system to the users and make it work in the real environment

19. The Rational Unified Model
Six Core Engineering Workflows
Business modeling – business use cases
Requirements – use cases
Analysis and design – design model – architectural model, component models, object models, and sequence models
Implementation – the system is coded
Testing – unit testing along with implementation, system testing after the system is completed
Deployment – a release is created and installed in the real environment

20. RUP: Six Best Practices
Develop software iteratively
Producing an executable release for the users keeps continuous user involvement and feedback and the developer stay focused
Manage requirements
Employ use cases and scenarios to capture requirements and to drive the design, implementation and testing
Use component-based architectures
Provides a systematic approach to defining an architecture using new and existing components

21. RUP: Six Best Practices
Visually model software
Use UML to visually capture the structure and behavior of architectures and components
Verify software quality
Quality assessment is part of the process in all activities with all participants.
Control changes to software
Describes how to control, track and monitor changes.

22. Agile Software Development
Agile Manifesto:
“We are uncovering better ways of developing software by doing it and helping other do it. Through this work we have come to value:
Individuals and interactions over processes and tools
Working software over comprehensive documentation
Customer collaboration over contract negotiation
Responding to change over following a plan
That is, while there is value in the items on the right, we value the items on the left more.”

23. Agile Methods Extreme Programming (XP) Scrum Crystal
Beck, extreme programming explained, 2000
Scrum
Cohn, Succeeding with Agile: Software Dev. Using Scrum, 2009
Crystal
Cockburn, Agile Software Development, 2001
Adaptive Software Development
Highsmith, Adaptive Software Development: A Collaborative Approach to Managing Complex Systems, 2000