Ridvan BOZKURT

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INTRODUCTION TO ENGINEERING IE 101 ATILIM
UNIVERSITY FACULTY OF ENGINEERING DEPARTMENT OF
INDUSTRIAL ENGINEERING 2009 2010 FALL SEMESTER

• Ridvan BOZKURT

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Definitions of design

• A goal directed problem solving activity
  L.B.Archer
• Decision making in the face of uncertainty with
  high penalities for error M.Asimov
• The creation of an end result that satisfies a
  human need by taking definite action J.P.Vidosic

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Definitions of design

• Stimulating what we want to make (or do) before
  we make (or do) it as many time as may be
  necessary to feel confident in the final result
  P.J.Booker

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Purpose of design

• The construction of a structure description that
• Satisfies a given (probably informal) functional
  description
• Conforms to the limitations of the target medium
• Meets implicit or explicit requirements on
  performance (time, space, power, cost, etc) and
  structure (style, simplicty etc)
• Satisfies restrictions on the design process
  itself

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Design activity

• defined as the planning and realization of a
  creative strategy to accomplish a physical,
  mental, moral or artistic task or to satisfy a
  real need

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Design activities

• Creativity
• Decision making
• Modelling

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Engineering Design Process

• Assemble design team
• Problem definition (identify the need and define
  the problem)
• Identify design limitations and constraints
• Preparing the project schedule
• Surveying and discussion of the related work
  (work share between the team members)
• Determining design specifications and selection
  of design criteria
• Developing conceptual design (alternative
  solutions, decision matrix, justification of
  selected design)
• Embodiment design
• Performance of design
• Conclusion

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Engineering Design Process (2. Problem definition)

• Develop an original and unique vehicle using
  only cardboard and glue/tape that can carry one
  of the team members for five meters

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Engineering Design Process (2. Problem definition)

• Objectives tree

Cardboard vehicle
Portability
Durability

• Maintenance
• Not easily
• broken
• Maximum
• durability

• Structure
• High load
• carrying
• capacity

• Movement
• Easily
• moved
• by pushing
• or pulling

• Transporting
• ease
• Low weight
• Small size

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Engineering Design Process (3. Design limitations
and Constraits)

• Has to carry app 70 80 kg
• Only glue/tape and cardboard can be used
• Repairing is not allowed during presentation
• Must be named clearly on it
• Should be completed at the end of this semester
• ..

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Engineering Design Process (4. Project Schedule)
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Engineering Design Process (5. Surveying and
discussion of the related work

• Who did what?
• Ridvan
• Researching factors that can reduce durability
  and finding ways to improve durability via
  several articles

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Engineering Design Process (6. Design
specifications and selection of design criteria

• Must be unique and original
• Must be carry 70-80 kg load for 5 meters without
  being destroyed
• Must be durable enough
• Minimum cost
• Appearance should be good
• Must be easy to construct

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Engineering Design Process (7. Conceptual design)

• You have to explain how to meet design criteria,
  their importance etc in this section
• Alternative solutions You have to generate
  alternative solutions to the problem and explain
  advantages and disadvantages. You must add
  figures, pictures, drawings etc.

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Engineering Design Process (7. Conceptual design)

• Decision matrix By preparing a decision matrix
  (after rank ordering and determining relative
  weighing factors for each criteria), you must
  choose the most appropriate one among the
  alternative solutions.

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Engineering Design Process (7. Conceptual design)

• Justification of selected design Justify why you
  will choose the solution resulted from the
  decision matrix.

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Engineering Design Process (8. Embodiment design)

• Explain how to construct the parts of your
  design, draw the figures of them and scale.
• Develop a production tree.
• Prepare cost table for your design

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Engineering Design Process (8. Embodiment design)
Production tree
Cardboard vehicle
Tyre-axle system
Body system
Ring

• Tyre
• 10 cardboard
• (Figure )

• Axle
• 1 cardboard
• (Fig)

Floor
Left side
right side
Rear
Front side
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Engineering Design Process (9. Performance of
design)

• After constructing your design, you should make
  tests and evaluate the performance according to
  design criterias

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Engineering Design Process (10. Conclusion)

• You must explain your project shortly

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THE ENGINEERING DESIGN PROCESS
1- Needs Assessment
5- Implemen- tation
Iteration
2- Problem formulation
4- Analysis
3- Abstraction and synthesis
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THE ENGINEERING DESIGN PROCESS

• Engineers focus on problems for which there are
  many practical solutions they seek the best
  solution from among these many alternatives

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1- Needs Assessment

• The need for a solution is first established
• Identify the objective(s) to be achieved by a
  solution
• Identify who will benefit from the solution
• In what way(s)?
• How do you know?
• Begin with the end in mind, know where you are
  going.

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2- Problem formulation

• The real problem to be solved is defined in the
  form of design goals that are to be achieved by
  any viable solution.
• Ask if the real problem differs from the problem
  as initially perceived or presented. In what
  way(s)?

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2- Problem formulation

• What or who was the source of the original
  problem statement? Did this source bias the
  statement in someway because of a unique
  perspective? If so, is the statement then
  incorrect or incomplete? In what ways?

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2- Problem formulation

• Structure the search for a solution. Identify as
  many different pathways leading to possible
  solutions as you can. Know where you are going
  and direct your search by pruning those paths
  that will (probably) not lead to a solution

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2- Problem formulation

• Acquire and apply technical knowledge as
  appropriate. In order to formulate the problem
  correctly and completely and to structure the
  search for a solution, one must take informed -
  that is, knowledable- decisions.

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2- Problem formulation

• Identify the design specifications (both explicit
  and implicit constraints or boundaries within
  which the solutions must lie)
• Identify the sources (time, money and personnel)
  that will be needed to obtain a solution

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2- Problem formulation

• Prioritize the design goals, continually review
  this list and modify it as needed during the
  remainder of the design process. Be aware that
  your initial priorizitation may be incorrect. Be
  open to change in your goal list. Focus primarily
  on those goals deemed most important, but
  recognize that all goals should be achieved by
  the final solution.

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3- Abstraction and synthesis

• Develop abstract (general) concepts or
  approaches through which the problem could be
  solved and then generate detailed alternative
  solutions or designs for the problem

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3- Abstraction and synthesis

• Recall related solved problems or experiences,
  pertinent theories and fundamental approaches (if
  any exists) to solving these types of problems

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3- Abstraction and synthesis

• Expand your thinking as to what is possible and
  what is not possible
• Seek to develop that are fully acceptable to all
  involved. What approaches can be taken to solve
  the problem? Which of these approaches is most
  valid? Why?

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3- Abstraction and synthesis

• Reconsider the problem statement Is it still
  valid or must it be modified?
• Be creative, use established and appropriate
  techniques for generating as many detailed
  solutions as possible

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3- Abstraction and synthesis

• Combine ideas for achieving each of the
  individual design goals into total solutions.
  Seek to make the whole (i.e.the complete design)
  greater than the sum of the parts (i.e.the
  individual ideas or subsolutions)

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3- Abstraction and synthesis

• Once again, expand your thinking as to what is
  possible and what is not possible. Be adaptable.
• Again reconsider the problem statement Is it
  still valid or must it be modified? Does your
  goal list need to be modified? If so, in what
  ways?

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4- Analysis

• Compare and evaluate alternative designs
• Choose a basis for comparing your alternative
  design solutions by establishing objective
  evaluation criteria

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4- Analysis

• Be critical of your work. Try to see your designs
  objectively and recognize each of their
  weaknesses or shortcomings (as well as their
  strengths)

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4- Analysis

• Consider fabrication/implementation requirements
  for each solution- for example, raw materials and
  standard parts (off-the-shelf components) to be
  used manufacturing processes needed to shape the
  raw materials into final form the impact that
  the production, distribution, operation and
  disposal of the fabricated design may have open
  the environment etc. Compare and contrast the
  requirements for each proposed design.

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4- Analysis

• Are each of the proposed solutions ethical in
  concept and operation (safe, environmentally
  responsible, etc)
• Eliminate alternatives that do not satisfy
  critical design goals

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4- Analysis

• Anticipate and avoid failure by eliminating
  weaknesses in your design focus upon others and
  their needs and expectations. Are there any
  inherent hazards in your designs? Can these
  hazards be eliminated or minimized?

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4- Analysis

• Does each design alternative satisfy appropriate
  ergonomic requirements (human-machine system
  dessgn goals and specs)? If not, why? Improve and
  refine each of your proposed designs, if possible.

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4- Analysis

• Construct prototypes of the most promising
  designs (if possible) and test/evaluate/refine
  their solutions.
• Select the best alternative from among these
  designs that remain available solutions to the
  problem.

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4- Analysis

• Select the best alternative from among those
  designs that remain available solutions to the
  problem

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4- Analysis

• Refine and refine this best design as
  appropriate eliminate or minimize weaknesses and
  shortcomings of the design. Can this best design
  be improved by combining it with elements from
  any or all of the other (rejected) alternatives?

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5- Implementation

• Develop the final solution and distribute it to
  your intended clients/customers/users

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5- Implementation

• After succesfully fabricating, testing and
  evaluating a design prototype (if such testing is
  possible), proceed with full production.
• Distribute to user population and obtain feedback
  for the next generation design

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Nth Generation Designs

• Design does not end with an optimal solution
• There is no perfect solution to an engineering
  problem
• Search for a better Nth generation design
  solution to a problem may continue endlessly
• Design process is repeated again and again as new
  and better solutions are developed

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Current practices in engineering design

• Life-cycle design
• Design for manufacture and assembly
• Design for quality
• Faster design cycles
• Engineering without walls
• Design for expert

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Current practices in engineering design
1-Life-cycle design

• (from conception through its manufacture and use
  to its final disposal)
• Manufacturing decisions can affect the economic
  viability and the functionality of a design

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Current practices in engineering design
1-Life-cycle design

• Most consumers dislike maintaining, servicing or
  repairing their products, so the designs should
  minimize or eliminate their needs
• Materials and components should be recycled to
  protect the environment and to generate cost
  savings for the manufacturer

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Current practices in engineering design 2- Design
for manufacture and assembly

• Any proposed solution can be properly
  manufactured
• Design manufacturing engineers work together to
  produce products innovative, cosy effective and
  manufacturable
• Components are combined when possible, if
  necessary eliminated

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Current practices in engineering design 3- Design
for quality

• Applied in order to ensure low failure rates
  coupled with high performance levels
• Identify and eliminate manufacturing and design
  defects

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Current practices in engineering design 4- Faster
design cycles

• CAD
• CAM
• FEA (finite element analysis)
• Microprocessor controls (reduce significantly the
  time required for developing new designs)
• Concurrent engineering (in which different phases
  of engineering design development and
  manufacturing are performed simultaneously)
  reduced this time

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Current practices in engineering design 5-
Engineering without walls

• Engineering departments within different
  companies often work together collaboratively to
  achieve a common goal
• Better designs
• More quickly
• More cost effective way

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Current practices in engineering design 6- Design
for expert

• Products are developed for the international
  marketplace
• Global product standards have been developed

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1- NEEDS ASSESSMENT

• ESTABLISHING NEED
• Engineers bring solutions to practical problems
• Concern for health, safety and quality of life of
  the public
• Personal experience of the design engineer

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1- NEEDS ASSESSMENT

• Recognition that an existing product must be
  redesigned in order to
• Eliminate shortcomings in the original design
• Better serve the changing needs of the user
  population
• Increase the commercial viability of the product
• Reduce costs

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1- NEEDS ASSESSMENT

• Safety and quality of life
• Typewriter for the blind
• Kidney dialysis treatment

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1- NEEDS ASSESSMENT

• Improving an Existing Product or System
• In order to be more effective
• Remain commercially viable
• DC Heart Defibrilliator
• Credit cards for the blind
• Cleaning up oil spills

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1- NEEDS ASSESSMENT

• Commercial incentives
• A new product line may be driven by the
  commercial needs of a company or of an individual
• Kwik Lok Closure
• Durable pants for miners

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1- NEEDS ASSESSMENT

• Personel experiences
• Quick release ski binding

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1- NEEDS ASSESSMENT

• Opportunities from scientific advances
• Advances in technology and/or in a specific
  discovery may create the opportunity for a new
  engineered product
• Color printing led to air conditioning

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1- NEEDS ASSESSMENT

• Color printing led to air conditioning
• In 1902 Willis H.Carrier, was striving to
  eliminate the negative effect that humidity had
  upon color printing. He realized that cold air
  could absorb humidity from warm air

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1- NEEDS ASSESSMENT

• Service to the humanity
• Engineers usually focus upon societys most basic
  physical needs
• They must work closely with many people
• Engineering is a people oriented and people rich
  profession

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1- NEEDS ASSESSMENT

• Focusing on others the key to success
• Design Failure Any inability of an engineering
  solution perform its intended function(s)
• Error Underlying cause for such failure(s)

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1- NEEDS ASSESSMENT

• A design error will be reduced if the engineer
  focuses on others
• Engineers must always be aware of the potential
  hazards associated with their work

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1- NEEDS ASSESSMENT

• Engineers must be aware of the harmful
  consequences of actions taken and not taken
• If an engineered system or product fails, the
  underlying cause of the failure (error) must be
  identified and eliminated

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1- NEEDS ASSESSMENT

• Concrete level A specific physical source is
  identified as a contributory cause of the failure
• (The failure of the O-ring seal between the
  interlocking joints of the booster rockets in the
  Challenger allowed escaping gases to be ignited
  by the rocket flames in 1986)

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1- NEEDS ASSESSMENT

• Process level Invalid assumptions, faulty
  reasoning, flawed execution of a procedure lead
  to the failure
• (One valid assumption was that the O-ring
  gaskets and putty would be sufficient to ensure
  that the interlocking joints would remain sealed)

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1- NEEDS ASSESSMENT

• Values/attitudes/perspective level A flawed
  value system contributes to the failure
• (Morton Thinkel MT- was the booster rocket
  manufacturer for the Challenger. MT executives
  overrode the objections of fourteen of their own
  engineers when they approve the final launch of
  the shuttle system. Executives did not want to
  disappoint NASA officials for fear that such
  disappointment would adversely affect upcoming
  contact negotiations between MTNASA. Poor
  decision making)

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1- NEEDS ASSESSMENT

• Design Proposal
• is a plan that provides the engineer with the
  opportunity to
• Justify the need for a technical solution to a
  problem
• Express this need in precise and accurate terms

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1- NEEDS ASSESSMENT
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1- NEEDS ASSESSMENT

• A Desing Proposal should answer the following
  questions about the work to be performed
• Why?
• Who?
• Where?
• How?
• When?
• What?
• How much will it cost?

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1- NEEDS ASSESSMENT

• Objective (Why?)
• Objective should be described in a clear and
  conscise form
• Do not assume that the need for a solution is
  self-evident
• Focus on function

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1- NEEDS ASSESSMENT

• Background (Who? Where?)
• Who will be served by the solution
• The environment in which the design is expected
  to be used (where)
• Should demonsrate that engineers have a truly
  robust (broad and deep) understanding of the
  problem to be solved

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1- NEEDS ASSESSMENT

• Methodology (How?When?)
• Describe the approach that will be used to design
  and develop the desired solution
• Each task to be performed should be identified
  together with the person(s) who will be
  completing these tasks

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1- NEEDS ASSESSMENT

• A schedule for the expected completion of these
  tasks should be included (Gantt Chart)

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Planned duration
Planned milestone event
Completed milestone event
Actual duration
Sequential dependency
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1- NEEDS ASSESSMENT

• Critical Path Method (CPM)
• can be used to indicate the expected times to
  complete sequentially dependent tasks and to
  identify that sequence or critical path between
  events that determines the total time needed to
  complete the project

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Critical Path Method (CPM)
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1- NEEDS ASSESSMENT

• Expected results
• Will the deliverables of the work be abstract (a
  set of recommendations presented in the form of a
  report) or concrete (a manufactured product)?
• The expected benefits and potential risks of the
  effort should be delineated.

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1- NEEDS ASSESSMENT

• Costs
• Expected costs of the porposed effort
• Labor
• Materials
• Facilities
• Other factors

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Focus on function
• A specific problem should be formulated if one is
  to develop a specific solution
• A problem statement should focus on the
  function(s) to be performed by any viable solution

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Focus on function
• Developing a better ink pen
• Protection of the pens ink supply from the air
  until its deposit on the paper, thereby allowing
  faster-drying ink to be used
• An even distribution of ink to the document

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Focus on function
• Do not define the problem in terms of an existing
  product
• (You may simply generate variations of this
  product)

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Formulating the real problem
• Engineering is an iterative process
• One should be prepared to reconsider assumptions,
  decisions and conclusions reached during the
  earlier stages of the design process if any new
  results indicate the need to do so.

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• The dangers of misdirected search
• A problem statement can be incorrect, leading to
  a misdirected search for solutions.

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Reentry of Space Capsules
• Problem statement
• Develop a material that is able to withstand
  the extremely high temperatures of reentry.
• During the late 1960s and early 1970s, such heat
  resistant materials had still not been developed.
• Problem statement was reformulated
• Protect the astronauts

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• The problem statement is the most critical step
• Engineers must strive to determine the real
  problem to be solved
• In real life engineering, you may be asked to
  solve ill-defined or incorrectly defined problems
• How does one determine the real problem to be
  solved?

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• The statement-restatement technique
• Determine the real problem (in contrast to the
  stated problem)
• Determine the actual constraints or boundaries
  (in contrast to the given or inferred boundaries)
• Identify meaningful goals (in contrast to a set
  of given or inferred goals)
• Identify relationships between inputs, outputs
  and any unknowns.

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Determine the real problem
• Varying the emphasis placed on certain words and
  phrases in the problem statement
• Ask yourself in the focus of the problem itself
  has changed. If so, in what way? Is this a better
  focus?

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Determine the real problem
• Substituting explicit definitions of certain
  terms in the problem statement for these terms
• Does this result in a different and more precise
  statement? If so, in what way?

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Determine the real problem
• Changing positive words to negatives and vice
  versa
• Try to identify ways in which energy is being
  wasted in a plant, rather than seeking ways to
  save energy.
• Does the modification then suggest that the focus
  of the problem statement should be changed? How?
  Why?

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Determine the real problem
• Replacing persuasive and / or implied words in
  the problem statement (obviously, cleary) with
  the use of such words
• Is this reasoning valid?
• What is the evidence for such reasoning?
• If the reasoning is invalid, should the problem
  statement be modified? In what way?

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Determine the real problem
• Expressing words in graphical or mathematical
  form and vice versa
• Has this improved your understanding of the
  problem to be solved? How? Why?

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Example Initial Problem Statement
• Increase the number of commuters who use public
  transportation
• Varying the emphasis on certain words and phrases
• Increase the number of customers by decreasing
  the price (sell monthly passes at reduced price?)
• Advertise the benefits (savings, safety, etc) of
  public transportation,
• Provide or reserve highway lanes for buses

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Sustituting explicit definitions for key words
• Encourage employers to reward employees who uses
  public transportation
• Provide office areas (desks, computers, etc) in
  train/buses for those who would like to work
  while commuting

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Changing positive terms to negative or vice versa
• Reduce the number of commuters who use public
  transportation
• Investigate the reasons for people failing to use
  public transportation (high cost, inconvenience)
  and try ro eliminate those negative factors or
  minimize their impact

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Replacing persuasive and/or implied words and
  investigating the underlying reasoning
  expressing words in graphical or mathematical
  format
• Increase the number of commuters who use public
  transportation, assumes that such an increase
  obviously will be beneficial because the number
  of people using private transportation then will
  be reduced
• Public commutersPrivate commuters Constant
  (total)
• If we increase the number of people in one
  category, the number in the other group must also
  decrease

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Determine the actual constraints or boundaries
• Constraints are usually quantitative (less than
  100 000 USD)
• Relax any constraints that are contained within
  the problem statement
• Design constraints usually should be quantitative
  rather than qualitative (less than 100 lbs, as
  opposed to lightweight)
• Replacing the word lightweight with not burden
  some to move or lift.

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Determine the actual constraints or boundaries
• Has the problem been modified in significant way?
• If not, work within more relaxed constraints
• If the problem has changed, determine the cause
  for this change

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Identify meaningful goals (in constrast to a set
  of given or inferred goals)
• Goals are qualitative (minimum cost, safety)
• Try to prioritize the goals and then focus on the
  most critical ones as you rewrite the problem
  statement

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Identify relationships between inputs, outputs
  and any unknowns
• What is the desired output(s) or benefit(s)?
• What are the inputs (raw materials, people,
  equipment, money, etc)?
• How will the inputs be transformed into the
  desired outputs?
• What is unpredictable in the process? Why?
• What additional data need to be collected?

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Determine the source and the cause Why-Why
  diagrams
• Does or can the source of the problem (a person,
  a journal article, data) explain how the problem
  statement was developed?
• Does the problem statement focus on the cause of
  the problem or merely its symptoms?
• Why-Why diagrams are used to identify the
  cause(s) of the problem

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2- STRUCTURING THE SEARCH FOR THE PROBLEM
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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Fault tree diagram
• Complex graphical tool is used to breake the
  potential underlying causes for a problem into
  ever more specific possibilities

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• The Revision Method
• (Improving an existing product)
• The product may be a current marketing success,
  but, it is expected to face increased competition
  from similar products in the near future
• Improvements in the design must be made
• Focus of the design effort occasionally should
  revert to the product or solution (rather than
  the specific function to be achieved by the
  solution

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Present State and Desired State via Duncker
  Diagram
• Another strategy for properly formulating a
  problem
• Modify either PS statement, DS statement or both
  until there is a satisfactory correlation between
  two.

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Example
• PS I need to study calculus
• DS I want to earn an A in IE 101
• PS I need to study calculus because I have an
  exam next week
• DS I want to earn an A in IE 101.

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• PS I am not sufficiently prepared for my
  upcoming calculus exam and I also need to work on
  my term project in IE 101
• DS I want to earn acceptable grades in both IE
  101 and calculus

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• PS I am not sufficiently prepared for my
  upcoming calculus exam and I also need to work on
  my term project in IE 101.
• DS I want to earn acceptable grades on both my
  IE 101 term project and my calculus exam

Direct and obvious correlation between PSDS
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Possible solution paths leading from PS to DS

• I must become more efficient
• I will speak to my professors and seek tutorial
  help
• I will decrease the number of hours each week
  that I spend watching television and devote this
  time to my academic work
• I will reformulate my term project, so that less
  time is needed to complete it.

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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Duncker Diagrams (General, Functional and
  Specific Solutions)
• A graphical tool that can be used to develop a
  set of matching PSDS statements
• Focuses on three levels
• General
• Functional
• Specific

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Duncker diagram with fictional case study of
family comp computers
PS Revenue is decreasing as computer
becomes increasingly unpopular
DS Increase revenue
General solutions
Make it OK if we do not increase sales to
households
Increase sales to households
Functional solutions
Decrease retail prices
Think of new household applications for machines
Find new markets for unsold achines
Specific solutions
Automatic banki
Access to electronic library collections
Market to industrial firms
Expand to foreign markets
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2- STRUCTURING THE SEARCH FOR THE PROBLEM

• General solutions
• Those that require some action be taken in order
  to achieve desired state
• Those that transform the DS until it matches the
  PS
• Sometimes NO action is taken, because PS may be
  actually preferable to all alternative states
  (NULL SOLUTION)

116
2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Functional/Specific solutions
• Generated without given consideration to
  feasibility
• Consider any or all possibilities for solving the
  problem (what if solutions)
• Those solutions are transformed (if possible)
  into specific solutions that are indeed feasible

117
2- STRUCTURING THE SEARCH FOR THE PROBLEM

• Fresh eye approach
• One explains the problem to another person (not
  someone on the design)
• May lead to a deeper understanding of underlying
  aspects of the problem
• May provide a new perspective of the situation
  that will lead to a more precise and correct
  formulation of the problem

118
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Engineers always walk within specific deadlines
  and search for solutions that lie within rigid
  constraints
• They must design and develop solutions in an
  effective manner
• Evaluate both the current problem state and the
  desired final solution state
• Develop a strategy for succesfully traversing the
  path from the problem state to the solution state

119
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Designing the search strategy
• In order to structure the path to be followed to
  a final design solution, we need to
• Eliminate paths that do not satisfy the desired
  design goals and/or constraints, since those
  paths do not lead to viable solutions

120
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Design our tasks so that they are most fruitful
  that is they will provide mere information or
  guidance in our problem solving effort
• Use various attributes of the final solution
  state to guide our choices in earlier decisions
  made along the solution path

121
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Eliminating impossible solution path
• Among twelve coins, eleven are normal and one is
  heavier in weight. Determine which coin is heavy
  one by using a balance scale no more than three
  times.
• In engineering design, you must work within real
  constraints and you must find the true solution
  to the problem.

122
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• What is a possible path or strategy that
  guarantees the success
• Place six coins on each side of the balance
• The scale must then tip downward in one direction
  or the other
• Assuming that it tips downward to the right, the
  heavy coin is among the six on the right side of
  the scale

123
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• By this first weighing, the number of candidate
  coins has been reduced to six
• Weigh remaining six candidates by placing three
  of them on each side of the scale
• The scale must tip downward, indicating which set
  of three coins must include heavy one

124
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Only three candidate coins now remain to be
  evaluated
• On the final weighing, place the remaining coins
  on the scale. If it remains balanced, the third
  candidate is the oddball otherwise the heavy
  coin is the one indicated by the imbalance of the
  scale.

WE ELIMINATE IMPOSSIBLE SOLUTIONS WITH EACH
WEIGHING UNTIL ONLY ONE POSSIBILITY REMAINED
125
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Extracting the most useful information
• HOMEWORK
• Identify the oddcoin and determine if it is
  indeed heavier or lighter than a normal coin.
• Constraint Only three weighing are allowed.

126
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• First weighing consists of eight coins on the
  balance, the other four coins off the scale
• If the scale remains balanced, the odd coin lies
  among the four off scale
• If the scale is unbalanced, the odd coin lies
  among the eight on the scale.

127
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Evaluating the final solution state
• Structure the search for a solution so that you
  are guaranteed success in a truly fashion
• Structuring the search can help engineers to find
  as many of these multiple solutions as possible

128
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Design your data collection and information
  gathering efforts so that the most (useful)
  information can be extracted the initial
  situation or problem state to be corrected
• Evaluate the final solution state by identifying
  the desirable elements (functional capabilities)
  that should be part of any solution

129
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Select intermadiate steps along the path from the
  problem state to the final solution state and
  develop the desired solution by following this
  path

130
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Subdividing the problem into design goals
• Safety
• Environmental protection
• Public acceptance
• Reliability
• Performance
• Ease of operation (operating conditions)
• Durability
• Use of standard parts
• Minimum cost
• Minimum maintenance and ease of maintenance

131
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Minimum cost
• A proposed design may be deemed economically
  infeasible and never produced
• Unexpected costs may cause a design to become
  economically infeasible after production has
  began, leading to its commercial failure

132
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Costs may be reduced in an arbitrary fashion,
  leading to design or manufacturing flaws
• Costs include
• Design and development of the solution
• Its production
• Its distribution
• Advertising
• Promotion and so forth

133
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Specific design goals
• Help us to define the particular problem that is
  to be solved
• Maintain our focus on the functions that are
  desired in a design solution
• Each design must achieve specific goals that
  pertain to the particular problem under
  consideration

134
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Problem Restraining the drivers and the
  passengers of an automobile at the moment of
  impact during a crash
• Goal 1 Improved seat belt or air bags (limits
  the imagination of design engineer)

135
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Goal 2
• Before impact The design must not restrict the
  user from quickly escape the vehicle
• During impact The design must operate
  effectively and automatically since the user
  cannot be expected to initiate or control its
  operation under such conditions
• After impact The design must not restrict the
  user from quickly escape the vehicle

136
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Other specific goals
• Weight
• Size
• Shape
• Speed
• Other factors

137
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Continuously reevaluating the goal list
• Project goals should be continuously reevaluated
• Initial goals may be divided into more specific
  tasks
• Additional goals wil likely be recognized

138
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Working with quantitative constraints Design
  specs
• Next task is to identify the constraints or
  specifications associated with each design goal
• Specs represent the quantitative boundaries
  within which our search for a solution must be
  conducted

139
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Some goals (the goal of safety) should be
  achieved completely
• Other goals must be defined in quantitative terms
  (lightweight-less than 5 kg, minimum cost-less
  than 1000 USD)

140
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Types of specs
• Physical space allocation, dimensional
  requirements, weight limits, material
  characteristics, enery or power requirements,
  etc.
• Functional or operational Acceptable vibrational
  ranges, operating times, etc.

141
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Environmental moisture limits, dust levels,
  intensity of light, temperature ranges, noise
  limits, potential effects upon people, other
  systems that share the same environment etc.
• Economic limits on production costs,
  depreciation, operating costs, service or
  maintenance requirements, and the existence of
  any competitive solutions in the marketplace.

142
2- STRUCTURING THE SEARCH FOR A SOLUTIONDESIGN
GOAL AND SPECIFICATIONS

• Legal governmental safety requirements,
  environmental or pollution control codes and
  production standards.
• Human factors/ergonomics strenght, intelligence
  and anatomical dimensions of the user.

143
3- ABSTRACTING AND MODELLING

• Abstraction provides us with a perspective of the
  building blocks that can be used to develop a set
  of design solutions.
• Synthesis is then used to form whole solutions
  fro these sets of building blocks or constituent
  parts.

144
3- ABSTRACTING AND MODELLING

• Abstraction
• Once the problem is formulated as a set of design
  goals, the engineer must develop a series of
  alternative design solutions
• The aim of absraction is to generate broad, more
  inclusive classes or catogories through which the
  problem situation (and various approaches to its
  solution) could be described and to obtain a
  conceptual perpspective or vision of the problemm
  and its possible solutions at relatively high
  levels of abstraction

145
3- ABSTRACTING AND MODELLING

• Requires the use of models to represent these
  different possible design solutions
• Abstraction allows us to consider a greater rabge
  of possibilities in which the problem can be
  dissected into parts or subproblems together with
  ways in which solutions to these subproblems can
  be coupled to form complete design solutions

146
3- ABSTRACTING AND MODELLING

• Generate as many as different alternative designs
  as possible in order to maximize the likelihood
  that we wil develop the best solution to the
  problem
• View the problem from a variety of perspectives

147
3- ABSTRACTING AND MODELLING

• First step in abstraction is to break the problem
  into as many different functional parts,
  subproblems or meaningful units as possible
  (parsing)

148
3- ABSTRACTING AND MODELLING

• Next, one should try to classify these functional
  aspectsof the problem into more general
  categories in accordance with their distinctive
  characteristics
• The general purpose that is to be achieved by a
  solution
• The principles or approaches that could be used
  to achieve this purpose, such as family of
  inventions that have been uzed to solve similar
  problems

149
3- ABSTRACTING AND MODELLING

• The context or operating environments in which
  the solution(s) might be used or
• The specific subtasks that must be performed
  (either sequentially or concurrently) in order to
  achieve the overall objective

150
3- ABSTRACTING AND MODELLING

• Importance of modelling in abstraction and design
• Modeling is part of the abstraction process
• Models are used to develop and evaluate ideas
• Models allows engineers to organize data,
  structure their thoughts, describe relationships
  and analyse proposed designs

151
3- ABSTRACTING AND MODELLING

• Models can help engineers recognize what they
  know and what they do not know about a problem
  and its solution
• Every design cannot be built due to financial
  constraints
• Prototypes often do nor work properly when first
  constructed, they require additional refinement
  and revision necessiating more investments of
  money and time

152
3- ABSTRACTING AND MODELLING

• Some designs may be hazardous to workers or to
  the environment, the engineers must minimize such
  hazards

153
3- ABSTRACTING AND MODELLING

• Models as purposeful representations
• A model can be
• A working scaled (concrete) miniature used to
  test an engineering solution
• An abstract set of equations describing the
  relationships among system variables
• A computerized simulation and anmation of a
  process
• A two or three dimensional graphical description
  of a design

154
3- ABSTRACTING AND MODELLING

• Purpose of a model
• Used to otain greater insight and understanding
  about that which is being represented
• A model is an abstraction of a problem and its
  proposed design solution(s)

155
3- ABSTRACTING AND MODELLING

• A model is created whenever engineers design a
  system or process that is too complex, too large
  or insufficiently understood to implement without
  further evaluation
• As the model is tested and refined, its precision
  and value as a representation of the real life
  process or system is enhanced

156
3- ABSTRACTING AND MODELLING

• Model formats and types
• Models can be abstract or concrete
• An abstract model mathematical/symbolic,
  graphical and computer based (simulation, finite
  element, CAD) should describe a context in
  sufficient detail to allow its evaluation and if
  necessary refinement

157
3- ABSTRACTING AND MODELLING

• If the evaluation determines that the concept is
  indeed valid, the abstract model may be used as
  the basis for a concrete representation (a clay
  mockup of an automobile, or a prototype of a new
  wheelchair configuration) of the design that can
  be tested and modified

158
3- ABSTRACTING AND MODELLING

• Some physical models can be quite crude, composed
  of clay, cardboard, rubber bands, glue and other
  materials that are easily available.

159
3- ABSTRACTING AND MODELLING

• Types
• Iconic
• Symbolic
• Analogic

160
3- ABSTRACTING AND MODELLING

• Iconic models
• Visually equivalent but incomplete 2 D or 3 D
  representations (such as maps and world globes)
• 3 D physical models of proposed bridges, highways
  and buildings
• 3 D models generated via CAD
• Actually resemble (look like) the process or
  system under consideration

161
3- ABSTRACTING AND MODELLING

• Symbolic models
• Higher level of abstractions of reality (such as
  the equations Fma or area of circle r2)
• Include the most important aspects of the process
  or system in symbolic form, neglecting all
  irrelevant details

162
3- ABSTRACTING AND MODELLING

• Mathematical models (sets of equations) can be
  used to describe and predict the behaviour of
  systems such as
• A set of masses, springs and dumpers used to
  represent a human being
• Orbital behaviour of a planet and its moons
• Two interacting populations (rabbits and foxes)
• Reaction between chemical compounds
• Traffic control flow process

163
3- ABSTRACTING AND MODELLING

• Analogic models
• Functionally equivalent but incomplete
  represenations
• Behave like physical process or system being
  modelled
• Miniature airplanes dynamically tested in
  windtunnels
• Electrical circuit diagrams
• Computerized simulations of manufacturing
  processes

164
3- ABSTRACTING AND MODELLING

• Developing the model
• What is to be gained from the model?
• Model can predict some system variable as a
  function of time
• Model can provide a descripiton of an object with
  sufficient detail for it to be manufactured
• Model can prescribe a porcess that should be
  followed in order to achieve a particular goal

165
3- ABSTRACTING AND MODELLING

• Types of models and the formats that could
  (should) be used to represent the system or
  process together with the reasons for selecting
  model types and formats
• (If the design is to be an innovative
  manufactured product, an abstract model followed
  by a concrete mockup of the system might be
  preferable)

166
3- ABSTRACTING AND MODELLING

• Is the model now useful relative to the purpose
  for which it was developed?
• Does the model accurately describe the system or
  process under consideration?

167
3- ABSTRACTING AND MODELLING

• Sketching
• Visual descriptions allow one to work with others
  in developing ideas quickly during brainstorming
  sessions and throughout the design process
• Simple freehand sketches do not need to be
  extremely accurate or detailed

168
3- ABSTRACTING AND MODELLING

• Purpose is to illustrate the significant elements
  of the design and detailed explanatory notes to
  avoid misinterpretations or confusion can augment
  them

169
3- ABSTRACTING AND MODELLING

• Model enhancement
• Explain the model to another person, this may
  lead to a deeper understanding of the models
  relative strenghts and weaknesses
• Identify boundaries or constraints on your model
  (are these realistic and consistent with the
  problem to be solved?)

170
3- ABSTRACTING AND MODELLING

• Your model reflects various simplifying
  assumptions (are these assumptions reasonable? If
  not, adjust your model)
• Try to develop sme additional simplifying
  assumptions and modify your model accordingly
• Are all known facts and data properly embedded
  within your model? If not, why?

171
3- ABSTRACTING AND MODELLING

• Do you need additional information?
• Are there similar problems/models available?
• Use another format to model the process or
  system. Compare the two format

172
3- SYNTHESIS

• Abstraction provide engineers with a perspective
  of the building blocks that can be used for
  design solutions
• Formulation of a whole from a set of such
  building blocks or constituent parts

173
3- SYNTHESIS

• Barriers to synthesis
• Knowledge blocks
• Perceptual blocks
• Emotional blicks
• Cultural blocks
• Expressive blocks

174
3- SYNTHESIS

• Knowledge blocks
• Engineering is the application of science to
  technical problems
• Engineers need to be knowledgable about
  scientific principles

175
3- SYNTHESIS

• Perceptual blocks
• Sometimes one is unable to properly discern
  important aspects of the problem that is to be
  solved

176
3- SYNTHESIS

• Perceptual blocks
• Stereotyping elements in a proposed solution or
  in the problem itself, thereby limiting our
  ability to recognize other interpretations of
  these elements

177
3- SYNTHESIS

• Perceptual blocks
• Delimiting the problem in which one imagines that
  additional constraints exist beyond the actual
  design specifications thereby unnecessarily
  restricting the range of possible solutions

178
3- SYNTHESIS

• Perceptual blocks
• Information overload Engineers must made through
  vast amounts of data in order to develop a
  sufficiently detailed understanding of a problem.
  The very expanse of available information can
  sometimes prevent one from developing an accurate
  understanding of the goals

179
3- SYNTHESIS

• Emotional blocks
• Fear of failure and the need for approval
• A need to follow prescribed paths and
  methodologies
• A tendency to accept the status quo in both
  problem formulation and the types of solutions
  that are generated

180
3- SYNTHESIS

• Emotional blocks
• Impatience leading to a quickly developed
  solution that may not solve the problem in an
  effective or optimal manner

181
3- SYNTHESIS

• Cultural blocks
• The culture within one company may discourage
  empoyees from ever considering new ways or
  performing routine tasks
• Another company may provide incentives for
  creative work by its employees in the form of
  financial bonuses, extra vacation time or
  promotions

182
3- SYNTHESIS

• Expressive blocks
• Inhibit ones ability to communicate effectively
  with others and with oneself
• Engineers need to be cautious about the
  terminology used to define a problem or to
  descrine solutions

183
3- SYNTHESIS

• Creativity stimulation techniques
• Brainstorming
• Brainwriting
• Each member records hir or her ideas on a sheet
  of paper
• Sheets are passed on to the next person
• Each individual can then build on the ideas that
  were generated earlier

184
3- SYNTHESIS

• Bionics
• Engineer searches for an existing solution within
  nature that can be adapted to solve the problem

185
3- SYNTHESIS
186
3- SYNTHESIS

• Checklisting
• Uses words and questions to trigger creative
  thought
• Trigger focus on
• Possible changes in an existing product, concept
  or system
• Quantity (increase, reduce)
• Order (reverse, stratify)
• Time (quicken, synchronize)
• State or condition (harden, straighten)
• Relative motion or position of components
  (attract, lower)

187
3- SYNTHESIS

• Checklisting (examples of trigger questions)
• What is wrong with it?
• What is similar to it?
• Why is it necessary?
• What can be eliminated?
• What materials could be used?
• How can its assembly be improved?

188
3- SYNTHESIS

• Can any components be eliminated?
• Is it unsafe?
• What does it fail to do?
• In what way is it inefficient?
• In what way is it costly?
• Who will use or operate it?
• Are there any other possible applications?
• What is it not?
• Can it be misused?

189
3- SYNTHESIS

• Examples of trigger words
• Accelerate
• Combine
• Cool
• Deepen
• Energize
• Harden
• Increase

190
3- SYNTHESIS

• Lessen
• Lift
• Lower
• Renew
• Rotate
• Slow
• Thin
• Widen

191
3- SYNTHESIS

• Obtain a fresh perspective
• Describe the problem that you are struggling to
  solve to someone else who is not involved in the
  design effort
• This person may be able to provide new insights
  and a new perspective

192
3- SYNTHESIS

• Inversion
• Engineer should concentrate on ways to make a
  product or system less effective and then invert
  these ideas to form ways in which the prodcut can
  be improved

193
3- SYNTHESIS

• Inversion
• (It may be very difficult to think of 25 ways in
  which energy can be saved in a building however
  if we try to think of 25 ways through which
  energy can be wasted, we will probably fing that
  some of these wasteful deas can be inverted)

194
3- SYNTHESIS

• Idea diagrams
• allow engineers to organize and correlate ideas
  as they are generated

195
3- SYNTHESIS
196
4- DESIGN ANALYSIS

• Once a set of alternative solutions to a problem
  has been generated, engneer is confronted with
  the task of determining which alternative is
  preferable, why is it preferable and what is
  wrong with it.

197
4- DESIGN ANALYSIS

• Techniques require engineer to
• Prioritize (or weight) the design goals against
  which each alternative will be evaluated
• Formulate a scheme by which ratings can be
  assigned to each design concept
• Combine the prioritized weightings

198
4- DESIGN ANALYSIS

• Combine the prioritized weightings of the goals
  with the ratings given do the designs to generate
  a combined score for each of the alternative
  solutions
• Compare the total scores of all the design
  alternatives in order to identify the best
  overall solution

199
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200
4- DESIGN ANALYSIS

• Final rank order of design goals for a computer
• Versatility
• Portability
• Performance
• cost
• Ease of use
• Availability of parts
• Maintenance
• Aesthetics

201
4- DESIGN ANALYSIS

• Assigning weighting factors to desig