Selective Dissemination of Information (SDI):
Selective dissemination of information is a method of supplying each user or a group of users with the references of documents or abstracts relating to their predefined areas of interest, selected from documents published recently/received during the period in question. This service saves the user the effort of having to scan through a number of publications, which can be very time-consuming, and to choose the documents of interest to him. Although SDI can be highly convenient from the user point of view, it may not prove useful unless the user and document profiles are carefully constructed and their matching is exact. Thus, the effectiveness of SDI service depends on the quality of user profiles and relevance of the publications matched with them. The 'user profile' comprises of a set of 'Key Words' organised as rigorously as the 'system' permits, which describe the subjects of interest of the user. These key words are compared with the key words appearing in the descriptions of documents and a document is selected when the two coincide. The corresponding references or abstracts are then sent to the user, usually accompanied by a feedback form on which the user can indicate whether the document really interests him, whether he needs a copy or why it is of no interest to him. On the basis of feedback, user's profile is updated. The feedback, thus collected, forms one of the important components of the SDI service.