Tuesday, March 12, 2013

The grounding of meaning in Asa H

1. We want to perceptually ground the meaning of linguistic concepts.  Sensors provide this directly for some words:

hear (sound)                                                         temperature
see                                                                        feed (recharge)
feel (touch)                                                           light level
yellow                                                                  time/date
green                                                                    hunger
blue                                                                      force
red                                                                        north
black                                                                    south
acceleration                                                         range
angular rotation/deflection                    wind speed and direction

For example, if an observer inputs the word "feel" when a touch sensor or force gauge is stimulated then the word's meaning is learned as an association (case) by Asa H.  I have given Asa H all of these concepts using NXT sensors.

top            bottom            left            right            front            back

can be defined by sensors that are placed in those locations.

2.  With pattern recognition Asa H can be taught to recognize letters, numerals, and common objects like:

roads                                                                     feet
heads                                                                    faces
hair                                                                       eyes
mouth                                                                   nose
people                                                                  body
chest                                                                     arms
hands                                                                    leg
male                                                                     female
fish                                                                       common plants
house                                                                    bird
wheel                                                                    table
chair                                                         some common sounds
go/moving                                                             hill

Preprocessors are likely to be useful/necessary (just as face recognition may be innate in humans).  I've built neural network recognition modules for both letters and numerals.

3.  Some meanings are learned at the next hierarchical level (or higher):

temperature < threshold  -----  cold                   collision and sensor pegged  -----  damage
temperature > threshold  -----  hot                    (we could give Asa a pain signal from this)
yellow  -----  color
green  -----  color                                 grasp and release and force zeros ---  drop
blue  -----  color
red  -----  color                                    push and displace > threshold  -----  soft/flexible
light level < threshold  -----  dark
range < threshold  -----  near                push and displacement < threshold ---- hard
range > threshold  -----  far                   far then later near -----  approach
left  -----  side                                                   right  -----  side
front  -----  side                                                 back  -----  side
grasp then lift then move  -----  take               
near then later far  -----  retreat                        

4.  Synonyms are learned when an observer inputs another word under similar conditions:

force  -----  push                                               force  -----  touch
collision  -----  hit                                             near  -----  close
far  -----  distant                                                top  -----  up
bottom  -----  down                                           top  -----  high
bottom  -----  low                                              feed  -----  energy
stop  -----  rest                                                  grasp  -----  hold
hungry  -----  need                                            retreat  -----  leave
feed  -----  good

These concepts constitute Asa's initial ontology.

Wednesday, March 6, 2013

Emergence in Asa H

Some simple concepts can be learned directly from sensory primitives.  A Lego NXT robot running Asa H software can:

sense an object inside its gripper's jaws at time step 1

close the gripper at time step 2

feel forces on the gripper jaws at time step 3

In this way Asa H learns the "grasp" concept.  If an observer inputs the word "grasp" at the same time then Asa H associates this name with the concept it learns.

As another example of a low level concept Asa H can learn:

with the robot moving forward at time step 1

sensing an object far ahead at time step 1

with the robot moving forward at time step 2

sensing an object near ahead at time step 2

sense a force of frontal impact at time step 3

In this way Asa H learns the "collision" concept.  If an observer inputs the word "collision" at the same time then Asa H associates this name with the concept it learns.

At the next higher level up in the Asa H hierarchical case memory Asa H learns:

sensing a collision at time step 1*

(some) sensor input sticking high (failing) at time step 2*

(some) sensor input sticking high at time step 3*

(some) sensor input sticking high at time step 4*


In this way Asa H learns the higher level concept "damage."  Again, if an observer sees the sensor
fall off and inputs the word "damage" then Asa H associates this name with the concept it learns.

Some of the important concepts that Asa H needs to know are at still higher levels in the case memory hierarchy.  These concepts emerge after the lower level concepts have been developed.

Friday, March 1, 2013

Asa H experiments

The following is an abstract I'm working on for a conference next year:

Our recently developed "Asa H" software architecture (KAS Trans. 109 (3/4): 159-167) consists of a hierarchical memory assembled out of clustering modules and feature detectors.  Various experiments have been performed with Asa H 2.0: 1. Don't advance the time step and record input components until an input changes significantly. 2. Time can be made a component of the case vector.  3. There is a tradeoff between time spent organizing the knowledge base (to reduce search needed later) versus search through a less organized knowledge base.  4. If utility is low search. Stop search if utility rises.  5. Cost of action can be a vector.  6. Before deleting a small vector component test if utility is changed when its deleted. 7.  Asa H has a number of parameters which are not easy to set. This set of parameters can be treated as a vector and Asa H can be run for a period of time while we record the utility gains.  A second set of parameters can be employed during a run in the same environment and the utility gain again is recorded.  With these vectors and utilities we can use the Asa H extrapolation algorithm in order to improve the parameter settings.

Asa H natural language understanding

I've studied the 1000 most commonly used words in english.  I believe I know how to teach Asa H 1/4 to 1/3 of the concepts involved in understanding these terms.  I am not sure how much will be required before Asa H can learn autonomously from the web or from human texts.  Would these requirements be relaxed if Asa could query humans when needed (for synonyms, linguistic examples, sensory examples, etc.)?  Such a query system would be easy to program in to Asa. (Triggered, say,  when the degree of match is too low.)