Page 116 - DLIS402_INFORMATION_ANALYSIS_AND_REPACKAGING

Unit 6: Information Retrieval Model and Search Strategies

concepts and the relationships among them. It is the result of a conceptual analysis that operates on Notes
the information need, which may be well or vaguely defined in the user’s mind.
This analysis can be challenging, because users are faced with the general “vocabulary problem” as
they are trying to translate their information need into a conceptual query. This problem refers to
the fact that a single word can have more than one meaning, and, conversely, the same concept can
be described by surprisingly many different words. Furnas, Landauer, Gomez and Dumais (1983)
have shown that two people use the same main word to describe an object only 10 to 20% of the
time. Further, the concepts used to represent the documents can be different from the concepts used
by the user. The conceptual query can take the form of a natural language statement, a list of concepts
that can have degrees of importance assigned to them, or it can be statement that coordinates the
concepts using Boolean operators. Finally, the conceptual query has to be translated into a query
surrogate that can be understood by the retrieval system.
Represents a general model of the information retrieval process, where both the user’s information
need and the document collection have to be translated into the form of surrogates to enable the
matching process to be performed. Figure 6.1 has been adapted from Lancaster and Warner (1993).

Figure 6.1

Document Collection

Conceptual Analysis

Transformation

Document Surrogates

Index Vocabulary
Thesaurus Matching Process Retrieved
Free-text text Surrogates

Query Surrogates

Transformation

strategy Conceptual feedback

Query
Search Conceptual Analysis Relevance

Information Need/ problem

Outline

An information retrieval process begins when a user enters a query into the system. Queries are
formal statements of information needs, for example search strings in web search engines. In
information retrieval a query does not uniquely identify a single object in the collection. Instead,
several objects may match the query, perhaps with different degrees of relevancy.

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