Search (4 results, page 1 of 1)

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Abstract

The wealth of chemical information on the INSPEC database is easily retrieved using the printed subject indexes to the associated abstract journals. However, this subject indexing is insufficient for machine retrieval, and free-text searching has special difficulties. An easy-to-use retrieval system has been developed which overcomes many problems, especially the retrieval of non-stoichiometric compositions, which are a feature solid-state chemistry. The scheme is limited to inorganic material, but allows flexibility and identification of dopants, interfaces and surfaces or substrates. At the same time, a system has been introduced for the online retrieval of numerical data included in the data base. This has successfully standardized the way in which such data is held for searching, enabling further refinement of searches where numerical information is significant

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Abstract

The depth of indexing, the number of terms assigned on average to each document in a retrieval system as entry points, has a significantly effect on the standard retrieval performance measures in modern commercial retrieval systems, just as it did in previous experimental work. Tests on the effect of basic index search, as opposed to controlled vocabulary search, in these real systems are quite different than traditional comparisons of free text searching with controlled vocabulary searching. In modern commercial systems the controlled vocabulary serves as a precision device, since the strucure of the default for unqualified search terms in these systems requires that it do so.

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Abstract

For truly effective subject access, it is essential that books on any given topic be brought together consistently under the same subject heading. With the advent of online catalogs, this goal has assumed new importance but has also become easier to achieve