CS 182 Sections 103 104

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CS 182Sections 103 - 104

• slides created by Eva Mok (emok_at_icsi.berkeley.edu)
  
• modified by JGM
• March 22, 2006

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The Last Stretch
Spatial Relation
Motor Control
Psycholinguistics Experiments
Metaphor
Grammar
Cognition and Language
Computation
Chang Model
Bailey Model
Narayanan Model
Structured Connectionism
abstraction
Neural Net Learning
Regier Model
SHRUTI
Computational Neurobiology
Triangle Nodes
Biology
Visual System
Neural Development
Midterm
Quiz
Finals
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Quiz

• How does Bailey use multiple levels of
  representation to learn different senses of
  verbs?
• Whats the difference between aspect and tense?
• Whats X-schema embedding? Give an example where
  embedding is necessary.
• How can Reichenbachs system be used with
  X-schemas? When does this system break down?
• What does the prefix affix tree look like for the
  following sentences
• eat them here or there
• eat them anywhere
• What does the affix tree look like after the best
  prefix merge?

4
Quiz

• How does Bailey use multiple levels of
  representation to learn different senses of
  verbs?
• Whats the difference between aspect and tense?
• Whats X-schema embedding? Give an example where
  embedding is necessary.
• How can Reichenbachs system be used with
  X-schemas? When does this system break down?
• What does the prefix affix tree look like for the
  following sentences
• eat them here or there
• eat them anywhere
• What does the affix tree look like after the best
  prefix merge?

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Baileys VerbLearn Model

• 3 Levels of representation
• cognitive words, concepts
• computational f-structs, x-schemas
• connectionist structured models, learning rules
• Input labeled hand motions (f-structs)
• learning
• the correct number of senses for each verb
• the relevant features in each sense, and
• the probability distributions on each included
  feature
• execution perform a hand motion based on a label

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Computational Details

• complexity of model ability to explain data
• maximum a posteriori (MAP) hypothesis

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data 1
data 2
data 3
data 4
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Limitations of Baileys model

• an instance of recruitment learning (1-shot)
• embodied (motor control schemas)
• learns words and carries out action
• the label contains just the verb
• assumes that the labels are mostly correct
• no grammar

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Quiz

• How does Bailey use multiple levels of
  representation to learn different senses of
  verbs?
• Whats the difference between aspect and tense?
• Whats X-schema embedding? Give an example where
  embedding is necessary.
• How can Reichenbachs system be used with
  X-schemas? When does this system break down?
• What does the prefix affix tree look like for the
  following sentences
• eat them here or there
• eat them anywhere
• What does the affix tree look like after the best
  prefix merge?

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Aspect

• Aspect is different from tense in that it deals
  with the temporal structure of events
• Viewpoints
• looking at the same event at different
  granularity
• He was walking / He has walked / He walks
• Phases of Events
• zooming in at a level and focusing on a stage in
  an event
• He is about to walk / He finished walking
• Inherent Aspect
• perfective / imperfective (telic / atelic)
• He is walking / He is tapping his finger

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Some linguistics theories on Inherent Aspect

• Zeno Vendler (1957)s distinction on state,
  activity, accomplishment, achievement

FYI telic bounded atelic unbounded punctual
instantaneous
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Controller X-Schema

• The controller x-schema is meant to capture the
  generic structure of events.
• Aspect therefore marks (or profiles) certain
  states or transitions.

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The car is on the verge of falling into the ditch.
FALL
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He stumbled on the uneven road.
WALK
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She cancelled her trip to Paris.
TRAVEL
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Quiz

• How does Bailey use multiple levels of
  representation to learn different senses of
  verbs?
• Whats the difference between aspect and tense?
• Whats X-schema embedding? Give an example where
  embedding is necessary.
• How can Reichenbachs system be used with
  X-schemas? When does this system break down?
• What does the prefix affix tree look like for the
  following sentences
• eat them here or there
• eat them anywhere
• What does the affix tree look like after the best
  prefix merge?

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X-Schema Embedding

• You can blow up any state or transition into a
  lower level x-schema, allowing embedding

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He is almost done talking.
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They are getting ready to continue their journey
across the desert.
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She smokes. (habitual reading)
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Quiz

• How does Bailey use multiple levels of
  representation to learn different senses of
  verbs?
• Whats the difference between aspect and tense?
• Whats X-schema embedding? Give an example where
  embedding is necessary.
• How can Reichenbachs system be used with
  X-schemas? When does this system break down?
• What does the prefix affix tree look like for the
  following sentences
• eat them here or there
• eat them anywhere
• What does the affix tree look like after the best
  prefix merge?

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Mapping down to the time line

• we can use Reichenbachs system to map the
  controller X-schema down to a time line and get
  tenses

Speech Time (S) Reference Time (R) Event Time (E)
S
R
E
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He is talking
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He has talked
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He will have talked
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He would have talked...

• by the time the bell rang.
• if you had not shushed him.
• okay this is getting complicated
• interaction with modals like would
• could be a strictly past reading (case 1)
• possibly a counterfactual (case 2)

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Not much of a stretch

• to get to metaphorical sentences like this
• The US Economy is on the verge of falling back
  into recession after moving forward on an anaemic
  recovery.
• You would just need to map from this physical
  domain (source domain) to the say, economics
  (target domain)
• the Event Structure Metaphor is exactly the
  general mapping from motion to changes, locations
  to states
• and then you need some domain specific mappings
• more on that in lecture

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Quiz

• How does Bailey use multiple levels of
  representation to learn different senses of
  verbs?
• Whats the difference between aspect and tense?
• Whats X-schema embedding? Give an example where
  embedding is necessary.
• How can Reichenbachs system be used with
  X-schemas? When does this system break down?
• What does the prefix affix tree look like for the
  following sentences
• eat them here or there
• eat them anywhere
• What does the affix tree look like after the best
  prefix merge?

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Affix Trees

• Data structures that help you figure out what
  merges are possible
• Each node in the tree represents a symbol, either
  terminal or non-terminal (we call that the
  affix in the code)
• Prefix Tree
• Suffix Tree

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Prefix Tree
r1 S ? eat them here or there r2 S ? eat them
anywhere
r1
r2
S
r1
r2
eat
r1
r2
them
r1
r2
here
anywhere
r1
or
r1
there
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Prefix Merge
r3 S ? eat them X1 r4 X1 ? here or there r5 X1
? anywhere
r4
r5
r3
S
X1
r4
here
r5
r3
anywhere
eat
r4
or
r4
them
r3
there
r3
X1
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Have a good Spring Break!!!