Similarity	Concept
	Information retrieval definition
	Operational information retrieval
	Cluster based retrieval
	Experimental information retrieval
	Information retrieval system
	Information structure
	Data retrieval systems
	Generality
	Clustered file
	Clustering

Pages with this concept

Similarity	Page	Snapshot
	72	Its main advantages are:1 it is easy to implement;2 it provides fast access to the next record using lexicographic order ...Its disadvantages:1 it is difficult to update inserting a new record may require moving a large proportion of the file;2 random access is extremely slow ...Sometimes a file is considered to be sequentially organised despite the fact that it is not ordered according to any key ...Inverted files The importance of this file structure will become more apparent when Boolean Searches are discussed in the next chapter ...An inverted file is a file structure in which every list contains only one record ...Index sequential files An index sequential file is an inverted file in which for every keyword Ki,we have ni hi 1 and a 11 <a 21 ...
	9	Sparck Jones has carried on this work using measures of association between keywords based on their frequency of co occurrence that is,the frequency with which any two keywords occur together in the same document ...The term information structure for want of better words covers specifically a logical organisation of information,such as document representatives,for the purpose of information retrieval ...The organisation of these files is produced by an automatic classification method ...Evaluation of retrieval systems has proved extremely difficult ...