Information Elicitation in the Space-Time Module

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Information Elicitationin the Space-Time Module
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Information elicitation

• Radar has only partial knowledge of the available
  resources and user needs.
• It may have to elicit additional information from
  the users and administrator.
• It needs to identify critical missing pieces of
  information and generate related questions.

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Example Initial assignment
Available rooms
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Roomnum. Area(feet2) Proj-ector
123 2,0001,0001,000 YesNoYes
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3

• Missing info
• Invited talk Projector need
• Poster session Room size Projector
  need

• Assumptions
• Invited talk Needs a projector
• Poster session Small room is OK
  Needs no projector

• Room requests
• Invited talk, 910am Needs a large room
• Poster session, 911am Needs a room

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Example Choice of questions
Initial assignment
2
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Posters
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Talk

• Candidate questions
• Invited talk Needs a projector?
• Poster session Needs a larger room? Needs
  a projector?

• Room requests
• Invited talk, 910am Needs a large room
• Poster session, 911am Needs a room

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Example Improved assignment

• Room requests
• Invited talk, 910am Needs a large room
• Poster session, 911am Needs a room

Info elicitation
System Does the poster sessionneed a projector?
Posters
UserA projector may be useful,but not really
necessary.
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Architecture
Top-level control
Processresource requests
. . .
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Choice of questions
Step 1 Fast heuristic pruning ofunimportant
questions.
Step 2 Slower selection of the most relevant
questions.
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Choice of questions

• Step 1 Fast heuristic pruning
• For each candidate question, estimate the
  probabilities of possible answers.
• For each possible answer, compute the respective
  change of the assignment utility.
• For each question, compute its expected impact on
  the utility, and prune questions with small
  expected impacts.

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Choice of questions

• Step 2 Selection of relevant questions
• For each remaining question and each possible
  answer, call the optimizer to search for a better
  assignment, and determine the resulting utility
  increase.
• Prune the questions that do not lead to
  significant utility increase.
• Send the remaining questions to the users.