Dissertation Information for Robert M. Losee NAME: - Robert M. Losee
- (Alias) Robert Losee
DEGREE:
- Ph.D.
DISCIPLINE:
- Library and Information Science
SCHOOL:
- University of Chicago (USA) (1986)
ADVISORS: - Abraham Bookstein
COMMITTEE MEMBERS: - Don R. Swanson - Clement Tak Yu
MPACT Status: Fully Complete
Title: THE PERFORMANCE OF PROBABILISTIC MODELS OF DOCUMENT RETRIEVAL SYSTEMS
Abstract: The sequential learning model makes use of knowledge available about probabilistic distributions describing term occurrences. Methods for estimating initial values for parameters of the models consistent with binary independence and two Poisson independence assumptions are given. Use of the two Poisson independence assumptions leads to inferior results with the MEDI033 database when compared to results of models making binary independence assumptions. Searches using synthesized random databases meeting the two Poisson independence and binary independence assumptions suggest that models consistent with two Poisson independence assumption will outperform models consistent with binary independence assumptions, assuming all assumptions are met. Boolean queries are converted into conjunctive normal form and the disjunctions treated as single facets, or hyperfeatures, with frequencies computed as the sum or maximum of the frequency of the disjoined features. Experimental evidence is presented suggesting that the use of this model may be inferior to using the earlier non-Boolean model, although the increased query size may be responsible for this poor performance. Based on experimental evidence, it is suggested that, for increased precision, searches use (1) the binary independence model; (2)
Croft-Harper estimates of the initial parameters for non-relevant documents, with a high degree of confidence; (3) either ratio or equal term discrimination value estimates of the initial parameters for relevant documents, with a low degree of confidence; and (4) a proposed tie breaking rule to rank documents with identical binary profiles.
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MPACT Scores for Robert M. Losee A = 2
C = 15
A+C = 17
T = 2
G = 1
W = 2
TD = 2
TA = 0
calculated 2017-05-10 22:38:48
Advisors and Advisees Graph
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