bolette sandford pedersen, sanni nimb*, anna braasch university of copenhagen, * danish society for...
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Bolette Sandford Pedersen, Sanni Nimb*, Anna Braasch
University of Copenhagen, * Danish Society for Language and Literature
Merging specialist taxonomies and folk taxonomies in wordnets
- a case study of plants, animals, and foods in the Danish wordnet
LREC 2010 2
• Introduction to DanNet Food taxonomies in DanNet based on DDO: ideal cases and problems
• Interrelating natural and functional taxonomies in DanNet
• Conclusions
Outline
LREC 2010
• Joint work: University of Copenhagen & Society for Danish Language and Literature
• Monolingually-based approach:
Danish lexical sources based on corpora:
The Danish Dictionary (DDO); SIMPLE-DK
• International frameworks: Princeton WordNet, EuroWordNet
• 60,000 synsets ≈ concepts• 200,000 semantic relations• Open source – download: wordnet.dk
DanNet – a wordnet for Danish
LREC 2010 4
DDO
• Semi-automatic establishment of hyponym hierarchies by extraction of identified genus expressions in DDO
• Monolingual approach
Introduction
LREC 2010
Princeton WordNet: large number of e.g. fishes and vegetables, represented with both an animal or plant sense as well as a food sense
-> same goal for edible animals and plants in DanNet: 2 hierarchies with a high number of synsets
Food taxonomies in DanNet based on DDO: ideal cases and problems
LREC 2010
Food taxonomies in DanNet based on DDO: ideal cases and problems
Reuse of DDO, ideal cases : edible plants and animals should have two
separate senses in DDO with two different genus expressions:
1= plant/animal. Biological genus expression = ”animal”, ”plant”, ”part of animal”, ”part of plant” …
2= food. Functional genus expression = ”food”, ”meat”, ”vegetable” …
LREC 2010
Food taxonomies in DanNet based on DDO: ideal cases and problems
Genus expression sense 1= gallinaceous bird
Genus expression sense 2 = meat
(turkey)
LREC 2010
Food taxonomies in DanNet based on DDO: ideal cases and problems
artichoke:• only one sense • genus expression: flower bud• part of definition: edible, but no food sense
established
Study: 74 DDO lemmas with polysemy plant/animal and food Conclusion: More than half demand manual treatment. Why?
(edible)(flower bud)
(artichoke)
LREC 2010
Food taxonomies in DanNet based on DDO : ideal cases and problems
1. DDO = traditional -> zoological and botanical domains strongly influenced by professional descriptions:
• Preference given to biological senses (in spite of corpus evidence)
• Genus expression: Botanical/zoological terminology (tomato = fruit, spinach = herb, pheasant = gallinacean )
2. First version of DDO - a printed dictionary -> food sense left out due to space limits
3. DDO not ontology-driven -> descriptions made ´bottom up’. -> No predefined vocabulary of definition-> No systematic treatment of regular polysemy
LREC 2010
‘Physical’ versus ‘functional’ genus expressions
• Observation: DDO definitions of concrete objects tend to use a ‘physical’ genus expression (object, stick , ball ..)
-> few ’functional’ genus expressions (toy, tool, equipment, food..)
Examples, Princeton WordNet:
‘ball’ = round object that is hit or thrown or kicked in games’BUT hypernym in WordNet = game equipment (NOT object)
‘doll = a small replica of a person, used as a toy’. BUT hypernym in WordNet = toy (NOT replica)
• Conclusion: Genus expressions are not fully reliable for the establishment of functional hierarchies
LREC 2010
Interrelating taxonomies in DanNet
Task of DanNet editors:
• Establish regular polysemous synsets where missing in DDO in order to account for layman’s food perspective
• Harmonize the different DDO approaches in a consistent way
• Ensure that clash of taxonomies does not mess up the general structure of the network
LREC 2010
Harmonize the different DDO approaches in a consistent way
We strive towards individual, but interrelated taxonomies in DanNet:
Food taxonomy of meat, vegetables and fruit i.e. FUNCTIONAL KINDS in Cruse’s
terminology (Cruse 2002)
Botanical/zoological taxonomies (in practice incomplete)
i.e. NATURAL KINDS in Cruse’s terminology
LREC 2010
Interrelating taxonomies
Encoding strategy in DanNet:Synsets interrelate with the two taxonomies either
By means of regular polysemy Example: lamb_1 (animal), lamb_2 (meat: food)
or
By means of multiple inheritance Examples: tomato (fruit/part-of-plant AND vegetable: food) rubarb (stalk/part-of-plant AND fruit: food)
LREC 2010
Interrelating taxonomies
lamb_1
tomato_1
vegetablefruit
lamb_2
meat
Zoological Food
Botanical Food
animal
Regular polysemy
LREC 2010
Not all concepts represented in both taxonomies
Only in food taxonomy:
grøntsag (vegetable) rodfrugt (root
vegetable) krydderurt (spice herb) suppeurt (potherb) vildt (game) flæsk (pork) indmad (offals)
Only in natural taxonomy:
plante (plant) skærmplante
(umbelliferous plant) rod (tuber) stilk (stalk) indvolde (entrails)
LREC 2010
Tricky cases (≈ false friends)
Examples of these are such as frugt (fruit) nød (nut) bær (berry)
In principle, these cases should evoke two (unrelated) synsets, one in each taxonomy
if you actually encode also the botanical ones
LREC 2010
Conclusions (1)
Foods taxonomies are typically folk taxonomies emerged spontaneously depending on the goods available and on cooking traditions of a particular region.
Inspired by and related to botanical and zoological taxonomies
The fact that terms are taken over from these natural taxonomies causes problems that require a consistent framework
Monolingual dictionaries do not always have a clear strategy
LREC 2010
Conclusions (2)
We have developed a framework that enables to distinguish and interrelate between the natural taxonomies and the functional taxonomies of the network.
Even if you have monolingual lexical resources that are inconsistent in this respect, the monolingual starting point is important in order to capture correct conceptual structures of a given language
Work in progress! See wordnet.dk and andreord.dk