org.activemath.studentmodel2.data
Class EvidenceCombination

java.lang.Object
  org.activemath.studentmodel2.data.Evidence
      org.activemath.studentmodel2.data.EvidenceCombination

public class EvidenceCombination
extends Evidence

An EvidenceCombination represents a number of positive and negative evidences. An object of the EvidenceCombination class can be used like a normal evidence. However, it actually represents a combination of several positive and negative evidences in order to create a weighted evidence. It tries to solve the problem that evidences can be either positive or negative. The constructors of this class require a number, which specifies the number of positive and negative evidences this evidence-combination represents. Using the getSingleEvidence(int index) method, you can retrieve the single positive or negative evidences this evidence-combination consists of.

Since:

2010-06-02

See Also:

getSingleEvidence(int)

Nested Class Summary

protected static class

EvidenceCombination.EvidenceType

Field Summary

Fields inherited from class org.activemath.studentmodel2.data.Evidence

evidenceData

Constructor Summary

protected	EvidenceCombination(Evidence evidence, EvidenceCombination.EvidenceType evidence_type)
	EvidenceCombination(Evidence evidence, int num_pos, int num_neg) Creates a new evidence combination representing several positive and negative evidences.
	EvidenceCombination(ExerciseResult exResult, CognitiveProcess cognitiveProcess, String conceptId, int num_pos, int num_neg)
	EvidenceCombination(ExerciseResult exResult, CognitiveProcess cognitiveProcess, String conceptId, int distance, int num_pos, int num_neg)

Method Summary

static int	achievementToNumPosEvidences(double achievement, int num_total_evidences) Converts the achievement value (which is between 0 and 1) to a number of evidences.
double	getAchievement()
int	getNumberOfNegativeEvidences()
int	getNumberOfPositiveEvidences()
Evidence	getSingleEvidence(int index)

Methods inherited from class org.activemath.studentmodel2.data.Evidence

getCognitiveProcess, getCompetencyLevel, getConceptId, getConfidence, getData, getDifficulty, getDistance, getEventId, getExerciseId, getIRTdifficulty, getKey, getStepDuration, getTimestamp, getUserId, getWeight, isDirectEvidence, setCognitiveProcess, setWeight, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

EvidenceCombination

public EvidenceCombination(Evidence evidence,
                           int num_pos,
                           int num_neg)

Creates a new evidence combination representing several positive and negative evidences.

Parameters:

evidence - The base evidence on which the single evidences are based on.

num_pos - The number of positive evidences this object represents

num_neg - The number of negative evidences this object represents

EvidenceCombination

protected EvidenceCombination(Evidence evidence,
                              EvidenceCombination.EvidenceType evidence_type)

Parameters:

evidence -

EvidenceType - Whether this evidence is positive or negative.

See Also:

EvidenceCombination.EvidenceType

EvidenceCombination

public EvidenceCombination(ExerciseResult exResult,
                           CognitiveProcess cognitiveProcess,
                           String conceptId,
                           int num_pos,
                           int num_neg)

Parameters:

exResult -

cognitiveProcess -

conceptId -

num_pos - The number of positive evidences this object represents

num_neg - The number of negative evidences this object represents

EvidenceCombination

public EvidenceCombination(ExerciseResult exResult,
                           CognitiveProcess cognitiveProcess,
                           String conceptId,
                           int distance,
                           int num_pos,
                           int num_neg)

Parameters:

exResult -

cognitiveProcess -

conceptId -

distance -

num_pos - The number of positive evidences this object represents

num_neg - The number of negative evidences this object represents

Method Detail

achievementToNumPosEvidences

public static int achievementToNumPosEvidences(double achievement,
                                               int num_total_evidences)

Converts the achievement value (which is between 0 and 1) to a number of evidences. This is for creating an evidence combination and if one wants to represent an achievement value with a number of positive and negative evidences.

Parameters:

achievement - The achievement value to "convert"

num_total_evidences - Number of total evidences that will exist in the combination

Returns:

Number of positive evidences for an evidence combination to represent the specified achievement value.

See Also:

EvidenceCombination(Evidence, int, int)

getSingleEvidence

public Evidence getSingleEvidence(int index)

Parameters:

index - The index of the single evidence to return.

Returns:

A positive evidence, if index < num_pos_evidence, a negative evidence if index < num_pos_evidence + num_neg_evidence, otherwise null.

See Also:

getNumberOfPositiveEvidences(), getNumberOfNegativeEvidences()

getNumberOfPositiveEvidences

public int getNumberOfPositiveEvidences()

Returns:

The number of positive evidences this evidence-combination consists of.

getNumberOfNegativeEvidences

public int getNumberOfNegativeEvidences()

Returns:

The number of negative evidences this evidence-combination consists of.

getAchievement

public double getAchievement()

Overrides:

getAchievement in class Evidence

Returns:

the achievement