COMPUTER SCIENCE AND ENGINEERING
An Information Retrieval System is a system that is capable of storage, retrieval and
maintenance of information.
Information in this context can be composed of following:
Text (including numeric and date data)
Other multimedia objects
→ Of all the above data types, Text is the only data type that supports full functional
→ The term “item” is used to represent the smallest complete unit that is processed and
manipulated by the system.
→ The definition of item varies by how a specific source treats information. A complete
document, such as a book, newspaper or magazine could be an item. At other times each
chapter or article may be defined as an item.
→ The efficiency of an information system lies in its ability to minimize the overhead for a
user to find the needed information.
→ Overhead from a user’s perspective is the time required to find the information needed,
excluding the time for actually reading the relevant data. Thus search composition, search
execution, and reading non-relevant items are all
aspects of information retrieval overhead.
The general objective of an Information Retrieval System is to minimize the overhead of a
user locating needed information. Overhead can be expressed as
the time a user spends in all of the steps leading to reading an item containing the
needed information. For example:
Scanning results of query to select items to read
Reading non-relevant items etc ...