2. Retrieval Approaches
Presented By
Mudassar Hussain (16)
Muhammad Zeeshan Haider (18)
Class
Bs-LIS 8th Semester
Department Of Library & Information Sciences
University of Sargodha
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4. Basic Search
• Basic Search allows for keyword searching. You can limit a
search to a particular phrase by putting the phrase in quotation
marks (e.g. “global warming”). You can also use AND, OR,
NOT operators
• A basic search is simply what is says ; a basic, no-frills
searching that allow you to enter search word or phrase related
to your search .
• A basic search is also known as simple search.
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5. Basic retrieval Techniques
• Boolean operators.
• Phrase searching.
• Truncation.
• searching.
• Case sensitive searching.
• Range searching.
• Stop word searching.
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6. Boolean Searching
• Boolean searches allow you to combine words and phrases
using the words AND, OR & NOT.
• Also known as Boolean operators and use to limit, widen, or
define your search.
How do a boolean search?
Boolean Search Operators
• The Boolean search operator AND is equal to the "+" symbol.
• The Boolean search operator NOT is equal to the "-" symbol.
• The Boolean search operator OR is the default setting of any
search engine; meaning, all search engines will return all the
words you type in, automatically
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7. Examples
AND
• Using AND limiting a search by combining terms; it will retrieve
documents that use both the search terms.
Architect AND Software architect
OR
• Using OR broadens a search to include results that contain either of
the words you type in.
Architect OR Software architect
NOT
• Using NOT will narrow a search by excluding certain search terms.
Architect NOT Software architect
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10. Phrase Searching
• Is a type of search that allows users to search for documents
containing an exact sentence or phrase rather than containing a set
of keywords in random order.
• Phrase searching is used to retrieve a string of words (instead of a
single word).
• The term refers to a specific search syntax which involves using
quotation marks (") around a specific phrase .
Examples
• You might be looking for information on global warming in a
database, that database will interpret that search in one of two ways:
• “Global AND Warming",
• " Global Warming" as a phrase, as you probably intended it.
• “Teenage abortions"
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11. Truncation
• Truncation allows a search to be conducted for all the different
forms of a word having the same common roots
• This is useful when searching for the singular and plural form
of a word as well as for terms that can be reduced to a
common stem.
• Often the asterisk (*) is used but other characters can also be
inserted, including the exclamation mark (!), Question mark?
and pound sign #
• A number of different options are available for truncation like
Left truncation, Right truncation and middle truncation.
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12. • Left truncation retrievals all the words having the same
characteristics at the right hand part, for example, *hyl will
retrieval words such as “methyl” and “ethyl”
• Right truncation, for example the term of Network* as a query
results in retrieving documents on networks and networking.
• Similarly middle truncation retrieval the words having the
same characteristics at the left hand and right hand part, for
example, “Colo*r” will retrieval both the term “colour” and
“color”.
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15. Proximity Search
• A proximity search allows you to specify how close two (or more)
words must be to each other in order to register a match.
• There are three types of proximity searches
1. Word proximity
2. Sentence proximity
3. Paragraph proximity
Word Proximity
• A word proximity search specifies a range that all terms in the
proximity search must appear in. The terms must be contained in the
same document.
• Word proximity searches can be ordered proximity or unordered
proximity. Ordered proximity is more restrictive than the unordered
proximity search.
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16. Word Proximity
Ordered Proximity
• The ordered proximity operator is the forward slash /. Terms in an
ordered proximity search must be enclosed in quotes. Use ordered
proximity to specify the order in which terms must appear within a
given range to count as a match.
• For example, an ordered proximity search to find dog, cat, and rat
within a 10 word range must find dog first. Dog counts as one word
in the range. Both cat and rat must be found within the next nine
words to register a match. (In an unordered proximity, it would not
matter which term was found first; the other two terms must be
found within the next nine words.)
Example
• "content collection"/5
• Finds documents which contain content collection, in that order,
within a five word range.
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17. Unordered Proximity
• The unordered proximity operator is the at symbol @. Terms
in an unordered proximity search must be enclosed in quotes.
Use unordered proximity to specify a set of terms which must
appear within a given range in any order.
Example
• "create content collection"@14
• Finds documents which contain all three terms, in any order,
within a 14 word range.
• "work* process$"@25
• Finds documents which contain terms starting with work and
synonyms of the term process within 25 words of each other.
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18. Sentence Proximity
• A sentence proximity search allows you to search for terms which
fall within the same sentence. Unlike word proximity, which
requires you to specify a range for the search, Sentence proximity
requires that all terms in the search be found in the same sentence.
• Like word proximity searches, sentence proximity searches can be
ordered or unordered. The ordered proximity operator is /S. The
unordered proximity operator is @S.
Example
• "ordered operator"/S
• Finds documents which contain both terms, in the order listed,
within a single sentence.
• "multiple sentence searches"@S
• Finds documents which contain all three terms, in any order, within
a single sentence.
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19. Paragraph Proximity
• A paragraph proximity search allows you to search for terms which
fall within the same paragraph. Unlike word proximity, which
requires that you specify a range for the search, paragraph proximity
requires that all terms in the search be found in the same paragraph.
• Like word proximity searches, paragraph proximity searches can be
ordered or unordered. The ordered proximity operator is /P. The
unordered proximity operator is @P.
Example
• "special proximity codes"/P
• Finds documents which contain all three terms, in the order listed,
within a single paragraph.
• "paragraph searches"@P
• Finds documents which contain both terms, in any order, within a
single paragraph.
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21. Case sensitive searching
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• Case sensitive searching allows searches for words that differ in
meaning based on differing use of uppercase and lowercase letters.
Words with capital letters do not always have the same meaning
when written with lowercase letters.
Examples
• A person from Poland is Polish, but you polish is used to clean and
shine something.
• You eat an apple while using an Apple for computer.
• the month of March is very different from what a marching band
does.
• Bill is the first name of former U.S. president William Clinton, who
could sign a bill (which is a proposed law that was approved by
Congress).
22. Range searching
• Range searching is one of the central problems in
computational geometry, because it arises in many applications
and a variety of geometric problems can be formulated as
range-searching problems.
• It is most useful with numerical information. The following
options are usually available for range searching
• greater than (>) less than (<)
• equal to (=)
• not equal to (/= or o)
• greater than equal to (>=)
• less than or equal to (<=)
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23. Example of Range Searching
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• To search for documents or items that contain numbers within
a range, type your search term and the range of numbers
separated by two periods (“..”). For example, to search for
pencils that costs between $1.50 and $2.50, type the following:
24. Stop word searching
• In computing, stop words are words which are filtered out before or
after processing of natural language data (text).
• In computer search engines, a stop word is a commonly used word
(such as "the") that a search engine has been programmed to ignore,
both when indexing entries for searching and when retrieving them
as the result of a search query.
• Some search engines don't record extremely common words in order
to save space or to speed up searches. These are known as "stop
words.“
Example
• The way to the school is long and hard when walking in the rain.
(* way to * school is long and hard when walking in * rain).
• The piano player.
(piano player).
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25. Advance Searching
• Advanced Search allows you to limit your search to Title,
Author/Creator, Subject, or Tag. You can also specify
“contains” “starts with” or “is (exact).” Specific dates and
languages can be selected. Resource type will limit your
search to a specific format or material type, such as Book or
Video/Film.
• An Advanced Search allows for a more targeted search by
using different indexes (author, title, subject, etc.) and limits
such as date range, material type, language, and library.
• Advanced Search allows you to filter your search using
specific parameters in order for you to receive results that are
more accurate.
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27. Fuzzy searching
• It is designed to find out terms that are spelled incorrectly at
data entry and query point.
• A fuzzy search is a process that locates Web pages that are
likely to be relevant to a search argument even when the
argument does not exactly correspond to the desired
information.
• Text retrieval technique based on fuzzy logic, finds matches
even where the keywords (search words) are misspelled or
only hint at a concept. Offered by several search engines on
the internet and some computer databases.
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28. Fuzzy searching
• For example the term computer could be misspelled as
compter, compiter, or comyter. Optical Character Recognition
(OCR) or compressed texts could also result in erroneous
results. Fuzzy searching is designed for detection and
correction of spelling errors that result from OCR and text
compression.
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29. 29
Query expansion is a retrieval technique that allows the end user to
improve retrieval performance by revising search queries based on
results already retrieved.
Query expansion
Start
Submit
Query
Conduct
Search
Present
search result
ENDSatisfied?Query Expansion
YESNO
30. Multiple Database Searching
• It means searching more than one IR systems. The need for
searching multiple databases seems threefold.
• First, searching in single IR system may not get what the user
is looking for.
• Secondly, multiple databases searching can serve as a selection
tool if the user is not sure which systems would be the best
choice for a given query .
• Third, result obtained from multiple databases searching can
suggest or indicate suitable systems for the user to conduct
further searches.
Examples
• EBSCOhost, ProQuest
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