SIMS 202 Assignment 4

Due September 29, 1998

Please bring hardcopy to class

Exercises:

WordNet
(1) Make a sketch (pen and paper is fine!) of a portion of the WordNet Lexical Net. Do this by first selecting a noun, then selecting one of its synsets (if it has more than one sense) and then selecting its hypernym until you reach a hypernym that has meronym (parts-of) relations. Descend down the hyponyms of a few of the meronyms. Continue until you've shown five or six relations. An example for which this sequence of operations produces results is canary. However, you can use a different sequence of operations if you like and a different starting word.

(2) This exercise is borrowed from my colleague Philip Resnik.

(a) Write down, in English, between 2 and 10 different senses of the verb "break". You may be able to come up with more, but 10 is plenty! Fewer is also ok. For example, here are two:

 

1. break an object into pieces
Example: Edgar broke the vase.

2. break a bone
Example: Mildred broke her wrist.

Try to do this without a dictionary if you can, but if you're not a native speaker of English, use a dictionary if you need to.

(b) Go to one of the web pages for using WordNet online, and look up the verb senses for "break".

Which WordNet senses do your senses from part (a) match, if any? (One of you senses might match more than one WordNet sense, of course.) For example,

Sense 1: Matches WN senses 2,3,4,5

(c) Do any of your senses group naturally into a class with common elements of meaning? How would you group them? (Use a hierarchy if that makes more sense.)

(d) How do these variations in word meaning relate to our discussion of centrality of category membership and characteristic features?

Note that this is an exploratory exercise, and there is no "correct" answer! Don't spend too long, not more than an hour.

(3)

• (a) How is WordNet different than a standard thesaurus (like Roget's thesaurus)?
• (b) How is WordNet different than a standard dictionary?
• (c) How is WordNet different than an encyclopedia?
• (d) How is WordNet different than a classification thesaurus like ERIC?
Hierarchical Classification vs. Facets

 (4) Yahoo! (a catalog service for the World Wide Web) employs human categorizers to assign selected web pages to categories. A (variation of a) small fragment of the Yahoo category system is shown here. (Names surrounded by * indicate actual web pages, as opposed to categories of web pages.)

(a) Is this a hierarchical or a faceted classification system?

(b) Convert the category system from its given structure (hierarchical or faceted) to the other of these two kinds of structure. Show where each of the categories and web pages appears in your converted structure. (You may refer to line numbers rather than writing out the entire name of each category to save time if you like. The numbers have no meaning except to act as a quick way to refer to the categories.)

(c) Is this new arrangement better? Why or why not?

Last modified Sept. 22, 1998.