Search Logic Viewing Results Labs 3-4 Dr. Dania Bilal IS 530 Fall 2007

Boolean Logic  Search logic is based on Boolean logic  Boolean logic is a system for logical operations  Based on George Boole, An English mathematician  Boole was the first to define an algebraic system of logic in mid 19 th century.  Boolean logic has many applications in electronics, computer hardware and software, and database searching.

Boolean Logic & Database Searching  Boolean logic is used to organize concepts together in sets.  When searching any IR system (e.g., online catalog, database, search engine) using keywords and/or a combination of keywords and query processing is based in part on Boolean operators.

Boolean Operators  AND = for narrowing search results Ex: strawberry and vanilla and chocolate  OR = for expanding search results Ex: strawberry or vanilla or chocolate  NOT= for narrowing search results by eliminating unwanted concepts from search results  Ex: strawberry or vanilla not chocolate  (strawberry or vanilla) not (chocolate)

Boolean Operator OR  Used to build up concepts  Helpful for:  Synonyms or equivalent terms  Ex: occupations or jobs  Spelling variations  Ex: harbor or harbour  Related terms Ex: brain injury or head injury

Venn Diagram AND Strawberry and vanilla and chocolate

Venn Diagram OR Strawberry or vanilla or chocolate

Venn Diagram NOT (strawberry or vanilla) not chocolate

Beyond Boolean Truncation  Truncation is used  to expand search results by stemming a word or concept at its root  to obtain results with the variant forms of names and/or words  obtain variant spellings ? is the symbol used in Dialog  See Pocket Guide, p. 6, for use of multiple truncations

Beyond Boolean Nesting  Nesting is a technique used to group similar terms or terms that have relationships together to increase search results while forcing the retrieval software to change its order of processing of the Boolean operators based on their strengths.

Boolean Strengths  Boolean operators are executed based on their strengths, from highest to lowest:  NOT  AND  OR

Viewing Search Results  Type (t) command is used to view search results  Results can be viewed based on  Nine Dialog system-defined formats, and/or  See Workbook chap. 4.  Other format(s) are user-defined/based  Based on field tags rather than a standard format such as ti, ab, au, py.  Found in bluesheets

Type Command  Tags are found in a database bluesheets  Type command is composed of four parts: t set no./format/record no(s) Example: t s1/3/1-5 system-defined (format 3) Example: t s1/au,ti,ab/1-5 user-defined format with author, title, and abstract

Display Command  Display or DS allows viewing search sets or search history  Differs from Type command  Typing DS will display all search terms and sets performed in a search

Nesting  Search technique used to group similar terms or terms that have relationships together to increase search results  Used to force retrieval software to change its order of processing of the Boolean operators based on their strengths  Results in lower recall but higher precision

Nesting  Used when more than one Boolean exists in search query  Effectiveness based on how well you build blocks or nests for terms in a query  Use search grid or sheet for building concepts, then connect with appropriate operator.

Boolean & Other Features in Google: Class Activity  Work in a group  Examine how the Boolean, truncation, and search parameters covered in these slides are used in Google. You may want to check the Advanced features in Google and how to use Google.  You have 15 minutes.

Proximity Searching Overview  Proximity operators used to  Increase precision of search results  Avoid false drops or false hits that result from using keyword searching  Employed more in proprietary databases than in Web search engines

Proximity in Dialog  W  N  L  S  F  There are additional proximity operators that we will cover in class soon.

Guided Searching  Based on collaboration between IU faculty, students, and staff and system developers such as web search engines  ChaCha  Software developed by Indiana University alumni  Building alliance with Google and other engines  IU will offer human-aided academic search services through ChaCha (students, faculty and staff)  ChaCha specializes in machine-based searches augmented by knowledgeable human guides.