Analysis of the distribution of relevant answers to 41 search profiles among the 80 subject sections of Chemical Abstracts" revealed that the average profile requires 10 CA-subject sections for adequate coverage. The average printing expense could be reduced 25 percent by searching the individual profiles in the appropriate subject sections. (5…

The techniques of search strategy design for substructure searches of the Wiswesser Line Notation (WLN) file are described in detail. The Index Chemicus Registry System'' was used. (13 references) (Author/SM)

The experiences in developing current awareness services for selective dissemination of information from Chemical Abstracts'' Condensates data base are described. File standardization, the weighted-term method of searching, and the algorithm used to perform the search on the CDC 6600 computer and a user survey are discussed. (2 references)…

The set reduction algorithm is based on set theory and Boolean algebra rather than the graph-theoretic approach. Time trials with a small file of organic chemical structures indicate that the algorithm can be economically used for substructure (or complete structure) sequential searches on a file containing 30,000-50,000 computer-coded structures.…

The TSS (Topological Screens System) for substructure search was applied to the CAS Registry file making it searchable on-line. The TSS screens and the use of the screen indexes are described. Statistics on screen assignment are provided, and the strengths and weaknesses of the system are discussed. (Author/NH)