information search and retrieval
TRANSCRIPT
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Information Search and Retrieval
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There are three different techniques in
search and Resource discovery paradigms,
Information searching & retrieval
Electronic directories & catalogs
Information filtering
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Information search & retrieval
Information search and retrieval is a process of
finding and extracting information according to the
specification provided by a user
The main purpose of developing this process is to
support nave users in areas like electronic shopping
and home banking.
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The goals of information search and
retrieval:
To satisfy the customers up to the maximum extent
To reduce the cost.
To fastly execute the requested query. Computer
methods that are used to execute the query are, Method for finding exact match based on keyword.
Method for finding nearest neighbors.
Information search and retrieval is used in areas like
libraries where customers are concentrating oninformation seeking behavior.
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Electronic Directories and Catalogs
Directories and catalogs are used for the
following tasks
1)Information organizing 2)Information browsing
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Information Organizing:
Organizing refers to the way of organizing orarranging the information so as to make decisionsfor interrelating it.
Organizing the information in a static way isuseful for some people but causes harm to otherpeople.
The apprehension of organizing the information is
very intuitive which means that what one findseasy may be difficult for others to browsedepending on the requirement.
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Information Browsing:
It is defines as an activity that is guided by human foranalyzing the enterprise and identifying the details of
resource space.
There are two major problems that occur while
performing browsing, they are navigation issues anddisorientation issues of users.
These problems can be solved by using system that
supports different representation of similar
information.
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Information Filtering:
The objective f information filtering is to provide
access to relevant and variable information when a
user requests for it.
Information filtering is a process of selecting only
those information that matches the users request.
The purpose of this process is not responsible for
performing any kind of search but its only objective isto filter out inconsistent data.
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Software filters are used to provide access control.
local filter
Remote filter
Local filter:
Local filters are used for processing incoming streamof data.
Remote filters:
They are software agents that perform their task on
behalf of users. They help users to perform daily task,search and retrieve information, support decision-making
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INFORMATION SEARCH AND
RE
TRIEV
AL
Searching is a process of identifying/finding the
required information from a massive amount of
stored semi structured information. This is in contrast
to the database application that deals with thestructured format since it follow certain standards,
syntaxes and make use of data type that have
specific meaning
Examples: students database and email messages.
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There are two phases in which search process can be
accomplished. They are
End user retrieval phase
Publisher indexing phase.
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End user Retrieval phase:
The following steps must be followed in end user retrievalphase are,
A query is constructed by a user which specifies the search
method to be used.
Query is then sent to the server , that examines the query,process it and initiate the search process. The result is a
table that contains a list of matching documents called hit
list. This tables finally degenerate hit list is passed back to
the user.
Users then select the pertinent document according to
their requirement , scans it and print only the desired part
of a document.
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Publisher Indexing phase:
This phase is responsible for,
Making an entry of a document in the database.
Creating and updating indexes and pointers that are useful
while searching is performed
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What is a Document?
Examples: web pages, email, books, news stories,
scholarly papers, text messages, Word, Power point, PDF,forum postings, patents, IM sessions, etc.
Common properties
Significant text contentSome structure (e.g., title, author, date for papers;
subject, sender, destination for email)
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Documents vs. Database Records
Database records (or tuples in relational databases)
are typically made up of well-defined fields (or
attributes)e.g., bank records with account numbers,
balances, names, addresses, social security numbers,
dates of birth, etc.
Easy to compare fields with well-defined semantics to
queries in order to find matches
Text is more difficult
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Dimensions of IRContent Applications Tasks
Text Web search Ad hoc search
Images Vertical search Filtering
Video Enterprise search ClassificationScanned docs Desktop search Question answering
Audio Forum search
Music P2P search
Literature search
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InfrmationRetrievalTasks
Ad-hoc search Find relevant documents for an
arbitrary text query
Filtering Identify relevant user profiles for a newdocument
Classification Identify relevant labels for documents
Question answering Give a specific answer to a
question
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Models of Information Retrieval:
There are three models that are used for retrieving
information from the database in an efficient
manner. They are
Boolean information retrieval model
Vector space information retrieval model
Probabilistic information retrieval model
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Boolean information retrieval model:
Boolean refers to query specification which are foundusing word or phrases, which are combined usingstandard operators AND, OR, NOT.
The drawback of this model fetches those text filesirrespective of their locations.
The drawback of this model is that it does not giveany preference or priority to fetched document
The system is more effective if a query exactlymatches with the retrieved document and on theother hand results ineffectiveness id the result is notdefinite and accurate.
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Vector space information retrieval model
Vector space model is developed to overcome the
problems of Boolean model.
It performs vector comparison using cosine
correlation similarity method.
According to this method, the query matches the
text, when vector text is similar to vector query.
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Probabilistic information retrieval model:
This model is based on probability ranking criterion.
According to this criteria, every text present in the
database is given some priority.
Both vector space model and probabilistic model uses
Boolean queries.
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CHALLENGES AND PROBLEMS
ENCOUNTERD IN INFORMATION SEARCH The following are the various challenges that a rises
while searching information online.
Information is being uploaded on the internet at ahigh rate.
Since, the turnover of information is rapid, traditionaltools of information search are not sufficient for theconsumers. Therefore, a challenge is to design and
implement advances searching, filtering and datamining tools that maximize the search process of anindividual in terms of time, cost and informationneeds
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Sometimes the search results gets overloaded often
confusing the consumers.
Consumer learn the environment slowly by knowing what iswhere. Additionally, directories and catalogs may be provided
to the consumers that facilitate them to navigate and browse
the product information of their choice.
Today, the focus is on human technology interfaces,according to this feature, the information regarding
preferences of a customer is taken and intelligent and useful
information is provided to the consumer, but the challenge
here is, how to represent this useful information on thescreen. Developments are being made to use virtual reality for
displaying such information to user