Login

Publications  •  Project Statistics

Glossary  •  Schools  •  Disciplines
People Search: 
   
Title/Abstract Search: 

Dissertation Information for Ellen Marie Voorhees

NAME:
- Ellen Marie Voorhees

DEGREE:
- Ph.D.

DISCIPLINE:
- Computer Science

SCHOOL:
- Cornell University (USA) (1986)

ADVISORS:
- None

COMMITTEE MEMBERS:
- None

MPACT Status: Incomplete - Not_Inspected

Title: THE EFFECTIVENESS AND EFFICIENCY OF AGGLOMERATIVE HIERARCHIC CLUSTERING IN DOCUMENT RETRIEVAL

Abstract: "The major component of a document retrieval system is the component that searches the document collection and selects the documents to be returned in response to a query. Since users wait for the results of the search, the component must be efficient as well as effective. The main goal of this thesis is to compare clustered file searches and inverted file searches in order to determine under what circumstances one search is to be preferred over the other. A preliminary goal is to define a good cluster search.

Three types of agglomerative clustering strategies, the single link, the complete link, and the group average link methods, are investigated. Searches of the single link hierarchy, the cluster hierarchy used extensively in previous research, are shown to be inferior to searches of the other hierarchy types. Searches of the group average link and complete link hierarchies perform similarly for small collections; for larger collections, searches of the complete link hierarchy are more effective. A top-down search of the group average link hierarchy is the most time efficient search asymptotically.

The experimental evidence suggests that the difference in the efficiency and effectiveness of the complete link and group average link searches is due to the restricted depth of the complete link hierarchy. The depth of the group average link hierarchy increases as the size of the collection increases, but the depth of the complete link hierarchy does not. Thus the largest clusters in the complete link hierarchy are not very large, and the clusters can be accurately represented by centroids. Since the depth of the hierarchy does not increase with collection size, searches of the complete link hierarchy should remain effective for larger collections.

The top-down search of the complete link hierarchy is somewhat more effective than the inverted file search. The relative efficiency of the two searches depends on the relative efficiency of accessing a page and computing a similarity, since the cluster search accesses many more pages but computes fewer similarities than the inverted file search. For an inexpensive similarity measure, the inverted file search is much more efficient."

MPACT Scores for Ellen Marie Voorhees

A = 0
C = 1
A+C = 1
T = 0
G = 0
W = 0
TD = 0
TA = 0
calculated 2008-01-31 06:20:47

Advisors and Advisees Graph