Example searches for this article have been carried out on the Dialog platform, however, the same principle applies to any of the traditional online services that Inspec is available on (i.e. STN, Datastar, Questel and EINS).
When searching on Inspec it is sometimes desirable to restrict an answer set to a particular subject area within the database. This is especially true when a search is conducted using free language keywords. It is often the case that a word can have more than one meaning, and searching for that word can lead to the retrieval of many unwanted records which are not from the desired subject area. The Inspec classification can help minimise this problem.
The Inspec classification provides a hierarchical breakdown of the subjects covered in the database. It is updated annually and is incorporated many of the platforms that Inspec is available on. It can also be obtained separately from Inspec either in book form (2004 revision) or electronically.
Consider a search for articles discussing the use of iteration as a software technique. Simply searching the single keyword "iteration" is not appropriate as the word is not exclusively used to describe concepts within the subject area of computing. Many records, most of which will not be relevant, will be retrieved.
Additional keywords such as “program…” can be added in order to make the search more focused, but care should be taken when doing this as the word “Program” like “iteration” has alternative meanings in a variety of subject fields (e.g. computing, television etc.). Although using these words will result in records being retrieved from the desired subject area of software there is a high chance that unwanted records from other technological areas such as television will also be included in the answer set.
Start by searching for the word “iteration” in the title field of records.
?S ITERATION/TIS1 2239 ITERATION/TI?T Sl/TI,CC/1-3
Title: Efficient corrector iteration for DAE time integration in multibody dynamics
Class Codes: E2200 (Mechanical components, systems and devices); E0210L (Numerical analysis)
Title: Acceleration and filtering in the generalized Landweber iteration using a variable shaping matrix
Class Codes: A0765G (IR spectroscopy and spectrometers); A7820D (Optical constants and parameters (condensed matter)); A0260 (Numerical approximation and analysis)
Title: Iteration procedure for the capacity of discrete memoryless channel
Class Codes: B0240 (Probability and statistics); B0290F (Interpolation and function approximation (numerical analysis)); B6110 (Information theory)
The records above are typical of the 2239 that were retrieved. They come from different subject areas. Looking at the information contained in the titles it is apparent that records 1 and 2 are irrelevant to the scope of my search. Record 3 however, is relevant.
The classification codes on this record suggest that that C6110 would be an appropriate code to use in conjunction with the keyword “iteration” for restricting the search to the relevant subject area of the database and make the search more focused. Additional codes could be found by reviewing the codes on other records or by using the online classification list available on Dialog. This is accessed by using the EXPAND command: