b. How do context foazsed crawlers improve the
performance of web search? (4)

8. a. A database has five ueansacdons. Let min sup = 60% and min con f = 80%.
(7)
Find all frequent itemsets using Apriori algorithm.

TID items bought
{ A,O,N,K,E,Y} 7700
{D,O,N,K,E,Y¥} 7200
{MAKEY} 1300

7400 {M,U,C,K} .
{C,O,U,K,1,E} 7500

b. How are spaHal query processing handled by R-trees?
Illustrate, (5)

9. a. Spatial association mining can be implemented in at
least Ovo ways: (1) (8) dynamic computation of spatial
associaHon relationships among different spatial
objects, based on the mining query, and (2) pre-
computation of spatial distances between spatial
objects, where the association mining is based on such
pre-computed results. Discuss (1) how to implement each
approach efficiently and (2) which approach is

preferable under what situation.

b. Write a note on temporal mining.