Notes
Slide Show
Outline
1
Syllabus change
  • We are no longer going to cover robotics, vision and natural language as advanced topics in optional lectures.
  • Instead, we will substitute a lecture on natural language processing for the planning lecture.
  • Please see the revised syllabus for more details.


  • Problems?  See me.  I encourage you to give me feedback.
2
Introduction to
Advanced AI Topics
  • Vision
  • Natural Language Processing
  • Robotics
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Homework #2
  • We are not yet ready to hand out Homework #2.  We will probably have it ready for you by next week.
  • The second homework is on constraint satisfaction problems
    • You can either do it as an individual or as two students in a group.
    • If you’re interested in doing the team assignment, you should find a partner either by talking to people in class or by using the IVLE forum.
4
Advanced Topics Overview
  • Agents have sensors and actuators


  • Sensors:
    • Seeing (visual input) Ž Image Processing and Computer Vision
    • Hearing (audio input) Ž Natural Language Processing
  • Actuators:
    • Moving and manipulating Ž Robotics
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Computer Vision
  • Perception
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Definition: versus graphics
  • Graphics
    • Have world model W
    • Generate the sensory stimulus from the model
      S = f(W)


  • Vision
    • Generate the model from the sensors: W = f-1(S)
    • To think about: f() doesn’t have a proper inverse.  Why?
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Ambiguity in sensory input
  • Girls playing with dollhouses
  • Or giants playing with people?
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Definition: versus image processing
  • Image Processing
    • A transformation of data to other data
    • e.g., smoothing


  • Computer Vision
    • Reduction in data to a (more useful) abstraction
    • e.g., digit / face recognition
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Applications
  • Surveillance – can we detect objects or people as they move around our field of vision?
  • Handwriting recognition – from handwritten addresses to barcodes
  • Content based Image Retrieval – query for images using without any text features.  “Show me similar pictures”
  • Automated Driving – speaks for itself
10
Natural Language Processing
  • Communication


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Definition of NLP
  • Examines communication in human languages.
    • Theoretical and practical aspects.
    • Similar to vision, has production and understanding affects
      • Understanding: speech / text to meaning
      • Generation: meaning to speech / text
    • Both processes have inherent ambiguity
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Not so great newspaper headlines
  • Squad helps dog bite victim.
  • Helicopter powered by human flies
  • Portable toilet bombed; police have nothing to go on.
  • British left waffles on Falkland Islands.
  • Teacher strikes idle kids.
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Sample Applications
  • Restaurant Query converts English queries into SQL.
  • MS Dictation converts speech into text
  • Babelfish translates Web pages to different languages
  • Summarizing multiple news articles from the web
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Robotics
  • Planning in the real world environment
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Getting around
  • Effectors
    • Sensors on effectors? Is the output noisy?
    • Low-level: need to build higher-level abstractions


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Problems
  • Localization – where am I?
    • Mobile robots but also robotic arms
  • Mapping – what does my environment look like?
  • Moving – how do I get from here to my goal? What type of plan do I have execute?
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Applications of robotics
  • Robotic Flight – robotic helicopter, unmanned piloting
  • Path planning for exploration
  • Rock climbing, perhaps difficult even for some of us
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Summary
  • All three areas deal with search:
    • Vision: search for most likely world w given input sensor s
    • Natural Language Processing: given an input utterance / text i, find most likely meaning m
    • Robotics:
      • Localization: given unknown input configuration / location, determine configuration.
      • Planning: given goal g and state s output plan p to reach g from s
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Summary
  • All three areas use heuristics :
    • Vision: trihedral structure
    • Natural Language Processing: grammars of language, most frequent meanings
    • Robotics: decomposition of problems into cells, maximizing distance between obstacles
  • Many of these heuristics involve probability, which we will return to at the end of the semester.