Software Engineering

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Software Engineering

• John Bowles
• Computer Science Engineering

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Engineering

• The application of scientific and mathematical
  principles to solve practical problems for the
  betterment of society

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Software Engineering

• Application of principles of computer science and
  mathematical analysis to the design, testing, and
  evaluation of the software and systems that make
  computers almost everything work
• Process analyze user needs and design, develop,
  test, and deploy software to meet those needs

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Software Engineers

• Work as part of a team to design and develop new
  hardware and software systems
• General applications and utility programs
• Construction, maintenance and expansion of an
  organizations computer systems
• Configure, implement, and install computer
  systems for others
• Designed, developed, and tested control room
  monitoring station at the BP Refinery

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Occupational Outlook

• Employment projected to grow fastest and add most
  new jobs (38) in the next decade
• Requires BS in Computer Engineering or Computer
  Science
• Must learn new skills in conjunction with rapid
  changes in computer technology
• Rated 1 of 50 best jobs by CNN Money (April 2006)

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Employment Outlook
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Software Development Life Cycle

• Requirements typically includes both hardware
  and software
• Development Practices implementation practices,
  standards, techniques
• Testing discover errors, i.e., where
  requirements are not met
• Deployment

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Requirements

• Features and functions a system must have
• Goal Make it easy to do the right thing and hard
  to do the wrong thing

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Requirements(BP Monitor Station with hindsight)

• Persona artificial person used to represent
  system users and operators
• BP Operators arrive late leave early
• Poor communications from one shift to another
• May not observe warnings

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Requirements (continued)

• Use Case
• Includes normal operation and what can go wrong
• What happens if
• BP Normal daily operation
• Also valves left in wrong position, sensors not
  working, operators run system out-of-specification
  
• Operator interaction with the system
• BP Flow in and flow out on separate screens

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Development Practices(Goal More reliable
software)

• Structured Programming
• If-then-else
• For and Do-while loops
• Extensive application of function calls and
  library functions
• Object-Oriented code and languages
• Code and data in same module
• Design Patterns
• Pair Programming
• Test-Driven Development

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Testing Techniques

• Formal model based testing
• Data flow and finite state machine models of
  software code and requirements
• In parallel with development no longer at end of
  development cycle
• Boundary value testing
• Test on, below, and above boundary values
• BP test with levels above 9 feet
• Extensive use of simulation to test unusual
  events
• Operator training (Airplanes, Oil refinery, )
• Automatic software control systems