Information Retrieval Systems


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INFORMATION RETRIEVAL SYSTEMS
IV B.TECH - I SEMESTER (JNTUH-R15)
Ms. S.J. Sowjanya , Associate Professor , CSE Mr. N.V.Krishna Rao, Associate Professor, CSE Mr. C.Praveen Kumar, Assistant Professor, CSE

COMPUTER SCIENCE AND ENGINEERING

INSTITUTE OF AERONAUTICAL ENGINEERING

(Autonomous)

DUNDIGAL, HYDERABAD-500 043

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UNIT 1
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What is IR?

Systemcentered View

• IR is a branch of applied computer science focusing on the representation, storage, organization, access, and distribution of information.
• IR involves helping users find information that matches their information needs.
User- centered

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IR Systems
• IR systems contain three components:
– System – People – Documents (information items)
System

User

Documents

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Data and Information
• Data
– String of symbols associated with objects, people, and events
– Values of an attribute • Data need not have meaning to everyone • Data must be interpreted with associated attributes.
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Data and Information
Information
–The meaning of the data interpreted by a person or a system.
–Data that changes the state of a person or system that perceives it.
–Data that reduces uncertainty. • if data contain no uncertainty, there are no information with the data. • Examples: It snows in the winter. It does not snow this winter.
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Information and Knowledge
• knowledge – Structured information • through structuring, information becomes understandable – Processed Information • through processing, information becomes meaningful and useful – information shared and agreed upon within a community

Data

knowledge

information

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Information Retrieval
• Conceptually, information retrieval is used to cover all related problems in finding needed information
• Historically, information retrieval is about document retrieval, emphasizing document as the basic unit
• Technically, information retrieval refers to (text) string manipulation, indexing, matching, querying, etc.
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Definition of IRS
• An Information Retrieval System is a system that is capable of storage retrieval and maintenance of information. – Information may be a text(including numeric and date data), images, video and other multimedia objects.
• Information retrieval is the formal study of efficient and effective ways to extract the right bit of information from a collection. – The web is a special case, as we will discuss.
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• An IRS consists of s/w program that facilitates a user in finding the info. the user needs. – The system may use standard computer h/w to support the search sub function and to convert non-textual sources to a searchable media.
• The success of an IRS is how well it can minimize the user overhead for a user to find the needed info. – Overhead from user‟s perspective is the time required to find the info. needed, excluding the time for actually reading the relevant data. – Thus, search composition, search exec., & reading nonrelevant items are all aspects of IR overhead.
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Information Retrieval Systems