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IS-FBN, IS-FBS, IS-IAC: The Adaptation of Two Classic Algorithms for the Generation of Referring Expressions in order to Produce Expressions like Humans Do. Bernd Bohnet Innovative Language Technology - TTI GmbH and University of Stuttgart Institute for Visualisation and Interactive Systems.
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IS-FBN, IS-FBS, IS-IAC: The Adaptation of Two Classic Algorithms for the Generation of Referring Expressions in order to Produce Expressions like Humans Do Bernd Bohnet Innovative Language Technology - TTI GmbH and University of Stuttgart Institute for Visualisation and Interactive Systems
Overview of the Talk • The Framework • IS-FBN: Full Brevity extended by nearest neighbor • Properties • IS-IAC: Incremental Algorithm extended by C4.5 • Example Decision Tree • Properties • Influence of the Amount of Training Data on the Results • Summary and Conclusion
The Adapted Algorithms • Full Brevity (Dale, 1989)Computes all combinations of the properties P with increasing length and therefore finds the shortest RE • Incremental Algorithm (Reiter and Dale 1992; Dale and Reiter, 1995)Psycholinguistically motivated algorithm which uses a preference ordering
Description of the Method • We reused an implementation of (Bohnet and Dale, 2005)which was developed 2004 at the Macquarie University, Sydney • The implementation is based on the Paradigm: Problem Solving by Search • This is a standard AI approach which goes back to (Simon and Newell, 1963) • This approach allows to recast nearly all GRE algorithmsand to compare them in one implementation framework
entity in question compare compare IS-FBN: Full Brevity extended by Nearest Neighbour • We used the FB algorithm as basis to create larger and larger RE • We used the DICE-metric to classify each of the produced RE due to their human likeness • We compared the generated referring expressions only with the expression for expressions of the same track (DIST 0.66) (DIST 0.5) (DIST 1.00) Best RE: Human REs Current RE: DIST: 0,66 0,66 0,5 1,00
Properties of IS-FBN • Design goal: • get a high score • Properties: • FBN needs information for a distinct scene (track) • FBN imitates human behavior (only) • Brute force approach • It has a high DICE score
entity in question present? y n Entity color (1) (2) :n :n :n Decision tree (incomplete) IAC:Incremental Algorithm extended by C4.5 • We use the IA as basis • We use C4.5 learning technique to build a decision tree • The result of a classification is the next property for IA • The input for a classification are (1) the properties and values of the entity in question (2) the already used properties Simplifying a bit the case Current RE: Æ Instance: :y :y
yes yes no no Decision Tree for Furniture as build by C4.5 ‘type’ present? • The tree answers the question which attribute should be chosen next? • The tree is surprisingly small! • The read part is never chosen ‘colour’ present? ‘type’ (122/45) value of type value x-dimension sofa yes no chair fan desk size (3/0) orientation (6/3) orientation (18/11) size (5/2) value of y-dimension colour (75/12) yes no colour (6/1) Y-dimension (6/0)
Properties of IS-IAC • Design goal: • “human like generation of referring expressions” • beat IS-FBN • Properties: • The result is already good with small training set • Computationally cheap • It has a high DICE score
Influence of the Amount of Training Data • The following figures have been obtained by n-fold cross validation leaving one out • The values are the average for people and furniture sets • The n-fold cross validation is more precise compared to evaluation with development data: • The IS-IAC is much better with smaller training sets • The IS-FBN seems to win against the IS-IAC only with “paper thin” lead of one more training example per track! (or using the development data with a distinct distribution) • There was the possibility to use the development data + training data for the final run.Was this a possibility to “cheat” a bit? (We use the training data (only) for the final test.)
Summary and Conclusion • FBN imitates human RE • IAC works more human like, but produces less human like REcompared to FBN • IAC produce already good result with small training sets • IAC does not need training data for a distinct track! • It lost unlucky against the IS-FBN only with a small lead • It was interesting and fun! • Many thanks to the Organizers and Evaluators!