net.sf.openschema

Class SimpleFocusChooser

java.lang.Object

net.sf.openschema.LocalChooser

net.sf.openschema.SimpleFocusChooser

public class SimpleFocusChooser
extends LocalChooser

A LocalChooser that implements a simple set of focus heuristics described in McKeown (1985).

The heuristics are as follow:

• Shift focus to a previously mentioned, not in focus object (an object belonging to the previous potential focus list. The rationale is that text is more interesting when it changes focus and if the focus is not changed at that moment the entity will need to be re-introduced later on.
• Stay put with the current focus (to avoid giving the idea that a topic is finished when it is not).
• Come back to a topic in the focus stack.

Moreover, the links between the potential focus lists of the previous clause and the current one are also used as a factor to decide continuation. The most links exist, the most cohesive the text is expected to be.

Author:

Pablo Ariel Duboue

Nested Class Summary

Nested classes/interfaces inherited from class net.sf.openschema.LocalChooser

LocalChooser.Decision

Field Summary

Fields

Modifier and Type	Field and Description
protected Ontology	ontology Ontology, employed for the potential focus lists linking decision process.
static boolean	verbose Verbosity flag, defaults to off.

Constructor Summary

Constructors

Constructor and Description
SimpleFocusChooser(Ontology ontology) Constructor, receives the ontology.

Method Summary

Modifier and Type	Method and Description
LocalChooser.Decision	choose(List<Map<String,Object>> fds, List<Frame> defaultFoci, Object currentFocus, List<Frame> potentialFoci, List<Frame> focusStack, FrameSet frames) Choose the appropriate continuation, using some of McKeown (1985) strategies.
protected LocalChooser.Decision	chooseOnPotentialToPotentialLinks(List<Integer> candidatePositions, List<Frame> candidateDefaultFoci, List<Map<String,Object>> fds, List<Frame> potentialFoci, FrameSet frames) Final decision on a smaller set of candidates using the potential to potential links.

Methods inherited from class net.sf.openschema.LocalChooser

extractPotentialFoci

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

verbose

public static boolean verbose

Verbosity flag, defaults to off.

ontology

protected Ontology ontology

Ontology, employed for the potential focus lists linking decision process.

Constructor Detail

SimpleFocusChooser

public SimpleFocusChooser(Ontology ontology)

Constructor, receives the ontology.

Method Detail

choose

public LocalChooser.Decision choose(List<Map<String,Object>> fds,
                                    List<Frame> defaultFoci,
                                    Object currentFocus,
                                    List<Frame> potentialFoci,
                                    List<Frame> focusStack,
                                    FrameSet frames)

Choose the appropriate continuation, using some of McKeown (1985) strategies.

Specified by:

choose in class LocalChooser

chooseOnPotentialToPotentialLinks

protected LocalChooser.Decision chooseOnPotentialToPotentialLinks(List<Integer> candidatePositions,
                                                                  List<Frame> candidateDefaultFoci,
                                                                  List<Map<String,Object>> fds,
                                                                  List<Frame> potentialFoci,
                                                                  FrameSet frames)

Final decision on a smaller set of candidates using the potential to potential links.