• Stemming
  • The Porter Stemming Algorithm
• Abbreviation Extension
  • Use Abbreviation list
• Stopword filtering
  • Use Stop-word list
• Misspelled words
  • GNU Aspell
• Location-based queries
  • NER for location detection
• Part-of-speech (POS) tagging
  • Stanford POS tagger
• Named entity recognition (NER)
  • Stanford NER tagger
  • Person (e.g., Bill Gates)
  • Location (e.g., Hong Kong)
  • Thing (e.g., Table)

• Lexicon (e.g., DBpedia person, location, organization, and product lists)
• Stop-word list (e.g, of, the)
• Abbreviation list (e.g., ad for advertisement)

• The Porter Stemming Algorithm
• GNU Aspell
• Web page structure analysis
• KEA for key word extraction
• Stanford POS tagger
• Stanford NER tagger
• WordNet
• WordNet:: Similarity
• NLTK Toolkit
• bsddb — Interface to Berkeley DB library

• the chinese university of hk
• new york pizza
• How do I play mp3 using the java programming language

• Top 1000 queries ⇒ label them into 32 categories

1. Function Query2Term(string query)
   Input: a query, Output: terms of this query
   
   Example1: the chinese university of hk → [the chinese university of hk]1 ([]i is the i-th term of this query)
   Example2: new york pizza → [new york]1 [pizza]2
   Example3: How do I play mp3 using the java programming language → [play]1 [mp3]2 [use]3 [java]4 [program]5 [language]6
   
   
2. Function Term2Centroid(string terms)
   Input: terms of a query, Output: centroid of this query
   
   Example1: [the chinese university of hk]1→ the chinese university of hk
   Example2: [new york]1 [pizza]2 → pizza
   Example3: [play]1 [mp3]2 [use]3 [java]4 [program]5 [language]6 → mp3
   
   
3. Function synonym(string keyword)
   Input: a word, Output: a set of synonyms of this term in WordNet
   
   Example: synonym(car)
   auto, automobile, machine, motorcar

1. Function catURL(string category, string engine, int n)
   Input: a category, Output: top n URLs from search engines (e.g., Google)
   
   Example: catURL(cuhk, Google, 3)
   www.cuhk.edu.hk/
   www.cuhk.edu.hk/chinese/
   www.cuhk.edu.hk/gss/
   
   
2. Function keywordsURL(string URL)
   Input: a URL, Output: key words of Web pages for this URL
   
   Example: keywordsURL(http://www.cuhk.edu.hk/english/)
   research, education, shatin, campus, college, etc
   
   
3. Function synonym(string keyword)
   Input: a word, Output: a set of synonyms of this term in WordNet
   
   Example: synonym(car)
   auto, automobile, machine, motorcar

Workflow for query categorization