Modern Information Retrieval Chapter 1 Introduction

IR: representation, storage, organization of, and access to information items Logical view of documents full text text operations  elimination of stopwords  stemming  identification of noun groups full text  index terms (as in the back of a book) structure (as Table of Contents of a book)

User query not easy to specify information need  Find all the pages (documents) containing information on college tennis teams which: (1) are maintained by an university in the USA and (2) participate in the NCAA tennis tournament. To be relevant, the page must include information on the national ranking of the team in the last three years and the or phone number of the team coach.  keywords (or index terms) as query

pull and push  pull from the system  push to the user information filtering

Information retrieval and data retrieval semi-structured/structured relevant information/precise data difficult/easy to specify the need how to represent a document, process a query, and rank the results? Center of IR: relevance

Viewpoints of IR Computer scientist  Computer algorithms and techniques  How to structure, store, and retrieve information automatically? Librarian and information science researcher  Human-centered interpretation of the IR problem  How people interpret and use information?

WWW a single fact which changes the view of IR standard user interface low cost and great access  distance and time  publish free browsing and retrieval at WWW  shopping at a mall

Which techniques will allow retrieval of higher quality? Which techniques will yield faster indexes and smaller query response time? How will a better understanding of the user behavior affect the design and deployment of new information retrieval strategies?

The retrieval process

Figure 1.4

Figure 1.5

Text IR and multimedia IR representation of data (text, image, video, audio, music, etc.) indexing and searching