PROBLEM SOLVING

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PROBLEM SOLVINGSYSTEMS
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Problem Solving

• Humans have always needed food, clothing, shelter
  and healthcare.
• Early humans lived in caves and ate fruits and
  seeds of plants
• Problems of Society
• Disposal of wastes
• Production of enough energy
• Continuous supply of clean and safe water
• Problems of Individuals
• Skills in programming
• Impaired vision
• Sound quality of recording systems
• Communication between drivers

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Good Design in Problem Solving

• Low-cost and easy to use
• Benefits outweigh the problems
• Examples
• Telephones, internet, suspension bridges etc
• Superconductors
• Energy is lost in resistance as electricity flows
• Superconductors could only be made at around
  432oF
• Liquid helium was used but was too costly
• Some materials work in liquid nitrogen that could
  go up to -234oF
• Materials are brittle and hard to make into wire
  with such temperatures

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Method of Problem Solving

• Seven steps in problem solving
• Describe the Problem
• A statement describing the problem gives a way of
  thinking about the problem, like people working
  for long hours get a back pain.
• This description decides whether the problem is
  interesting, important ---- example on page 50
• Describe the Results
• Goals of solving the problem should be defined
• Design criteria --- list of specifications that
  includes all the requirements of the problem
• The specifications should also include the
  limitations of the problem

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Method of Problem Solving

• Gather Information
• Gathering information to solve a problem is
  called research
• Basic research --- nature of different materials
  and processes
• Market research --- determine if customers will
  like the new product
• Think of Alternative Solutions
• Past experience of others
• Brainstorming in a group for some creative ideas
• Develop alternatives by trial and error
• Insight --- an idea may just pop up into your
  head
• Some of the most important discoveries, like
  penicillin, have been discovered by accident

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Method of Problem Solving

• Choose the Best Solution
• Each alternative must be examined for design
  criterion and constraints
• Optimization --- changing or combining
  alternatives to improve them
• Tradeoff --- selecting the best overall solution,
  , e.g. cost and strength of a metal
• Implement the Solutions
• Prototype or model of the solution is made to
  check for cost, risks, e.g. model of an airplane
  in a wind tunnel
• Evaluate the Solution
• Observation may suggest some improvement in
  design or construction of the solution ---
  feedback
• Once satisfied, we can build the full-scale
  structure, or start mass-producing the product

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Modeling Design Solutions

• Charts and Graphs --- describe how an alternative
  solution might work
• Mathematical Models --- use of mathematical
  equation to predict performance
• Sketches, Illustrations, and Technical Drawings
  --- show ideas in picture form
• Working Models --- can be partly or fully
  functional. Its material and size may and may not
  be the same as that to be used
• Computer Simulation --- displays a picture of the
  idea on screen. It is most useful when a large
  number of calculations must be carried out

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Real World Problems

• Technological decisions must take both human
  needs and the protection of the environment into
  consideration
• Social/Environmental Concerns
• An airport or a nuclear plant cannot be built
  near a residential area
• Needs of the society or the community must be
  considered
• Politics
• Groups of people have different interests, e.g.
  in case of a nuclear power plant
• Risks of a new development should be traded for
  its benefits
• Risk/Benefit Trade-Offs
• Use of satellites, cars etc

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Real World Problems

• Continued Monitoring
• All the effects of a technological solution may
  not be known until long after the solution is
  implemented
• Some drugs may have harmful side effects
• Values
• Products advertisements have certain limitations
• Some people prefer a sports car or a luxury car
  while others go for a basic car

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Systems

• A system is a means of getting a desired result,
  e.g. space shuttle, calculator, car etc
• System Model
• The input is the command we give a system or its
  the desired result
• The process is the action part of a system --- it
  combines the resources
• The output is what is produced or its the actual
  result
• Feedback is information about the output that can
  be used to change it --- monitor --- system
  diagrams on page 65 and 67
• Systems with feedback are called control systems
  or feedback control systems or closed loop
  systems
• Systems without feedback are called open loop
  systems

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Systems

• Even our own bodies contain systems
• The body has many control systems like sugar
  level, heartbeat, oxygen collection etc.
• Multiple Outputs
• A system may produce several outputs
• The outputs from a coal-burning power plant may
  by
• Expected Desirable power
• Expected Undesirable noise and smoke
• Unexpected Desirable tropical fish is
  flourished in the warm water
• Unexpected Undesirable acid rain due to the
  pollution
• Subsystems
• Many smaller systems in a large system are its
  subsystems