Theory of search keys and applications in retrieval techniques used by catalogers

Abstract

This paper constructs a model for studying the performance of search keys of several types (such as, e.g., author/title keys of the form 414, 313, 3/1/1/l, and so on), end gives a criterion for deciding whether or not to use one (or several) more slashes (1) (i.e., more truncated title words) in a certain system (e.g., an automated library catalog). Some mathematical theorems on search keys are proved, given the probability distribution of letters (more general: symbols) in words. We then study the effect (on search key performance) of enlarging the " alphabet," i.e., when adding new symbols, that can be used in forming the search keys. Changing the alphabet might cause a change of optimal search keys. Criteria for this (not) to happen are given. The last part of the paper deals with the difference in average performance (averaged over ah possible systems) of search keys with less or more slashes (I). In general, we can prove that, on the average, introducing slashes does not improve the retrieval performance. Obviously, we can note the following trivial relations: ,~s < ,u2 and plilil < plil.

Type/Token‐Taken informetrics

“…Other examples of source/item informetrics are Key words (among which search keys or N‐grams) and their occurrence in a database (see Egghe, 1992, 2000; Kilgour, Long, & Leiderman, 1970); Articles and the references they give (synchronous citation analysis) or the citations they receive (diachronous citation analysis) (see, e.g., Stinson, 1981; Stinson & Lancaster, 1987); Books in a library and their borrowings in a certain time period (see Burrell & Cane, 1982), Services (e.g., at a library circulation or information desk) and their duration (measured, e.g., in seconds); Words and their occurrences in a text (e.g., a book) (see Herdan, 1960, 1964; Zipf, 1949). …”

“…Key words (among which search keys or N‐grams) and their occurrence in a database (see Egghe, 1992, 2000; Kilgour, Long, & Leiderman, 1970);…”

“… Search keys (e.g., N‐grams) are used by catalogers in a library network to quickly find out if a newly arrived book (hence, that must be cataloged) is already in the database. For a description of search keys (or N‐grams as a special case) see Egghe, 1992, 2000; Kilgour et al, 1970). The distribution of the occurrences (tokens) of the N‐grams (types) in the catalog will be different from the distribution of the occurrences of these N‐grams as experienced by the cataloger.…”