Engineering a Small System by Kurt Skytte

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Engineering a Small Systemby Kurt Skytte

• IEEE Spectrum, March 1994
• Presentation by JIN LYU
• 1/26/2004

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Systems Engineering

• Do it right the first time
• Overall technical management of the system
  development project
• Transform customers stated need into set of
  requirements and specifications
• Define necessary resources, tools and stages in
  product development process
• Plan check-up in each stage to verify products
  adherence to specifications and requirements and
  correct defects/errors
• Validate final design
• Standard in the U.S. Department of Defense and
  applied in large commercial products
• Not widely applied to medium/small-sized products

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Three assumptions

• Product should fulfill customers need
• Many companies fail to do so
• Poor understanding of customers need
• failed Ultrasound imaging instruments by GE and
  Phillips
• Minimize redesign
• The largest source of project delays
• System as a whole must be carefully planned out
• creeping elegance
• Specifications drive design

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6 phases in system engineering

• Requirements phase
• System design phase
• Detail design phase
• System Integration phase
• Design verification and optimization phase
• System validation phase
• Each phase produces formal documents that drives
  design process.

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Requirements phase

• Life-cycle cost depends on this stage
• Products objective is defined according to the
  customers need
• Multidisciplinary team is formed to develop
  detailed specifications for functional
  requirements
• Specifications define what to design not how to
  design
• Sets the priority among features to aid
  decisions if the tradeoffs must be made
• Quality function deployment (QFD) technique
• Finished when team is willing to commit to final
  document

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System design phase

• Translates completed functional requirements into
  an architecture and set of system-level design
  specifications
• Identify sub-system, component and define
  relationships among them as well as document how
  each satisfies functional requirements.
• Performance requirements are also produced
• Possible use of Computer-aided engineering (CAE)
  tools for verification of specifications
• System integration plan as well as acceptance
  criteria for both hardware and software is
  developed

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Detail design phase

• Actual design begins according to system design
  specifications
• Every aspect of design should be documented
• Design is reviewed against specifications several
  times
• Produces tested and verified components ready for
  integration into the system

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System integration phase

• Produces prototype system
• All the components and subsystem should be
  assembled in an order defined in integration plan
• Verification of functionality

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Design verification and optimization phase

• Verify system meets or exceeds all the
  requirements and system design specifications
• Optimize the system design so that difference
  between expected performance and measured
  performance are minimized

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System validation phase

• Last overall check before design is manufactured
• Thorough testing to see the final system design
  complies with the original functional
  requirements specifications
• Automated test tool is used to expedite this
  process
• System must be re-validated after modification or
  change

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Discussion