matching algorithm for concept browser about hive-mrc HOT 1 OPEN

Had the chance to look at this briefly in the context of the plural/singular 
problem:

HIVE is relying on Lucene for indexing and search. Lucene is indexing both the 
preferred and alternate labels. "Noxious mammals" includes the alternate labels 
"Harmful mammals" and "Injurious mammals", which appear to be increasing its 
score.

Test case:
1. Select vocabulary: Agrovoc
2. Search term: "mammals"
3. Results: 
  Noxious mammals (9.35)
  Mammals (6.64)
  Game mammals (4.15)
  Aquatic mammals (4.15)

Expected results:
  Mammals should appear first. We need to consider what to expect for the remaining results (perhaps factor in relationships -- is narrower/broader than exact match; whether phrase is in altLabel, etc).