Week 4 - Reading

Chapter 13


  • There are two different ways to deal with the problems arising from incomplete and incorrect information.
    • Conditional planning
    • Execution monitoring.
  • An agent that builds a plan and then executes it while watching for errors is, in a sense, taking into account the possible conditions that constitute execution errors
  • The condition must be known to the agent at that point in the plan.
  • A conditional planner therefore will sometimes create plans that involve carrying out ordinary actions for the purpose of obtaining some needed information.
  • A sensing action can have any number of outcomes.
  • Sensing actions of this type can be used in parameterized plans, where the exact actions to be carried out will not be known until the plan is executed.
  • A second approach is to check the preconditions of each action as it is executed, rather than checking the preconditions of the entire remaining plan.
  • If someone or something else has already changed the world so that the goal is achieved, action monitoring notices this and avoids wasting time by going through the rest of the plan. 
  • The difference lies in the time at which the computation is done and the information is available to the computation process. 

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