Package de.uni_trier.wi2.procake.similarity.base.taxonomy

Interface SMTaxonomyPath

All Superinterfaces:
SimilarityMeasure, SMTaxonomy
All Known Implementing Classes:
SMTaxonomyPathImpl
public interface SMTaxonomyPath extends SMTaxonomy
The similarity between query and case based on the shortest path between query and case in relation to the longest possible path.

To compute the similarity between two nodes first first the longest path in the taxonomy is searched. The path is required, to compute a value using the weights for up and down:

maxPathWeighted = weightUp * #maxStepsUpward + weightDown * #maxStepsDownward

For this, the height of the deepest node is taken and doubled. In many taxonomies, this path is longer than the real existing longest path. But it's important, that the value of maxPathWeighted is always the highest possible value. Using different weights for up and down, there might be different paths, with different steps counts. So, a overestimating path is used.

At next, the common parent of the nodes is searched. Second, the path is traversed up from query to the common parent and traversed down to the case node. Thereby, each step upward is weighted and each step downward is weighted.

The value for the path is calculated as follows:

currentPath = weightUp * #stepsUpward + weightDown * #stepsDownward

Using the values for nodePathWeighted and maxPathWeighted, the similarity is calculated as follows:

sim = (maxPathWeighted - nodePathWeighted) / maxPathWeighted

Author:
Rainer Maximini, Alexander Schultheis

  • Field Details

    • NAME

      static final String NAME
      Name of similarity measure is "TaxonomyPath".
      See Also:

    • DEFAULT_WEIGHT_DOWN

      static final double DEFAULT_WEIGHT_DOWN
      Default weight for steps downwards in path between nodes is 1.0.
      See Also:

    • DEFAULT_WEIGHT_UP

      static final double DEFAULT_WEIGHT_UP
      Default weight for steps upwards in path between nodes is 1.0.
      See Also:

  • Method Details

    • getWeightDown

      double getWeightDown()
      Returns:
      The weight for a step down.

    • setWeightDown

      void setWeightDown(double weight)
      Sets the weight for a step down.
      Parameters:
      weight - must be between 0 an 1. Other values will be rounded automatically.

    • getWeightUp

      double getWeightUp()
      Returns:
      The weight for a step up.

    • setWeightUp

      void setWeightUp(double weight)
      Sets the weight for a step up.
      Parameters:
      weight - must be between 0 an 1. Other values will be rounded automatically.