Introduction to Heuristic Search Methods

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Introduction to Heuristic Search Methods

• TMR4115
• Friday, Oct 10 2003
• Prof. Stein Ove Erikstad

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Optimisation in Design
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Ill-structured design problems
Perhaps something is to be learned by turning
the question around. We have generally asked how
problems can be provided with sufficient
structure that problem-solvers () can go to work
on them. We may ask instead how problem-solvers
of familiar kinds can go to work on problems that
are, in important respects, ill-structured. Simon
, 1973
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Goal-directed vsGenerative Design Methods
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Concept Exploration Models
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CEM Basic Steps

• GENERATE one, or a set of, design description(s)
• ANALYSE the description(s) to derive the relevant
  design performance(s)
• EVALUATE the performances with respect to the
  design goals
• DECIDE whether the current best solution is
  acceptable, or whether it is necessary to
  generate additional design solutions

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Representational spaces
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Examples of CEM applications

• a CEM used in the opening phases of warship
  design, by Eames and Drummond 1977,
• a CEM applied to merchant ship design, from
  Georgescu, et al. 1990,
• a CEM applied to a Naval SWATH design
  Nethercote, et al. 1981,
• QUAESTOR, presenting a knowledge-based approach
  to concept exploration models Hees 1992.

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Exploration vs Exploitation

• Exhaustive search not an option
• Bremmermans limit
• Need to make committments
• Meta-design Designing the design process
• Two-armed bandit problem

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Improving Process Efficiency

• Methods that aim to reduce the number of
  dimensions of the search space
• Methods that aim to reduce the size (extent) of
  the search space by imposing bounds and
  constraints on it.
• Methods that aim to select a subset of design
  descriptions to be interpreted
• Methods that aim to reduce the computational
  burden by reducing the complexity of the design
  interpretation

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Reducing search space dimensions
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