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Effective Web Searching

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Effective Web Searching Dr. I.R.N. Goudar Visiting Professor-cum- Library Adviser University of Mysore Refresher Course UGC- Academic Staff College – PowerPoint PPT presentation

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Title: Effective Web Searching


1
Effective Web Searching
  • Dr. I.R.N. Goudar
  • Visiting Professor-cum- Library Adviser
  • University of Mysore
  • Refresher Course
  • UGC- Academic Staff College
  • University of Mysore

2
Organization of the Web...
  • Web is the totality of web pages stored on web
    servers
  • Spectacular growth in web-based information
    sources and services
  • Education and research
  • Entertainment
  • Business and commerce
  • Personal home pages
  • Estimated to contain over 1 billion indexable web
    pages
  • Doubling each year
  • Over 80 million web sites

3
Finding relevant documents on the Web
  • Informal
  • Browsing (and book marking for later use)
  • Friends
  • Print sources
  • Discussion forums (mailing lists)
  • Current awareness services (e.g. Scout Report)
  • Guessing web site addresses!
  • Formal (using information finding tools)
  • Web directories/ guides
  • Web search engines
  • Meta-search tools
  • Specialty search engines

4
Three Types of Internet Searching Tools
  • Subject Directories or Subject Trees such as
    Yahoo.
  • Search Engines such as Google, Teoma, and Alta
    Vista.
  • Metasearch Engines such as Dogpile and Mama, and
    ixquick

5
Limitations
  • Anyone can put up a web page
  • Many pages not updated
  • No quality control
  • most sites not peer-reviewed
  • less trustworthy than scholarly publications

6
Web Directories/ Guides
  • Also called as virtual libraries and Internet
    resource catalogues
  • Organised collection of descriptions and links to
    Internet sources
  • Organisation by subject categories
    (hierarchical) by resource type (patents,
    e-journals, institutes, etc.)
  • Most use human experts for source selection,
    indexing and classification
  • Some include reviews/ ratings of listed sites

7
Web Directories/ Guides...
  • Examples of general web directories
  • Internet Public Library(http//www.ipl.org/)
  • Britannicas Webs best sites
    (www.britannica.com)
  • Infomine (infomine.ucr.edu)
  • Scout Report Signpost (www.signpost.org)
  • BUBL link (bubl.ac.uk/link)
  • Yahoo (www.yahoo.com)
  • Magellan (www.mckinley.com)
  • Galaxy (www.galaxy.com)
  • Looksmart (www.looksmart.com)
  • Snap (www.snap.com)

8
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9
Web Directories/ Guides...
  • Guides to directories
  • WWW Virtual Library (www.vlib.org)
  • Subject-specific guides (subject gateways)
  • Intute (http//www.intute.ac.uk/)
  • IOP Physicsworld.com (http//physicsworld.com/)
  • Chemcenter (www.acs.com)
  • Programmers Heaven (www.programmersheaven.com)
  • Resource type guides
  • Patents (www.european-patent-office.org)
  • Electronic journals (www.publist.com)

10
Web Search Engines
  • Web search engines build a full-text index to web
    pages gathered from web sites and provide a
    keyword search interface to this index
  • Spider programs periodically visit web sites and
    gather the web pages for indexing
  • Also index web sites submitted by site developers
  • A brief summary of the indexed web page is also
    prepared
  • The index usually contains URLs, titles,
    headings, and other words from the HTML document

11
Web Search Engines...
  • Examples
  • Fastsearch (alltheweb.com)
  • Altavista (www.altavista.com)
  • Google (www.google.com)
  • Northernlight (www.northernlight.com)
  • HotBot (www.hotbot.com)
  • Excite (www.excite.com)
  • Teoma (http//www.teoma.com/)

12
Web Search Engines...
  • Specialty search engines
  • Country-specific search engines
  • www.khoj.com
  • www.123india.com
  • Subject-specific search engines
  • Chemfinder (www.chemfinder.com)
  • Engineering Resources Online (www.er-online.co.uk)
  • MathSearch (www.maths.usyd.edu.au8000/MathSearch.
    html)
  • World Trade Locator (www.intl-tradenet.com)
  • Resource-specific search engines
  • Patents (www.uspto.gov)
  • Journal articles (www.findarticles.com)

13
Meta Search Tools
  • Also know as multi-threaded search engine
  • Allows the user to search multiple databases
    simultaneously, via a single interface and return
    results in a uniform format
  • Presents a summary of the collected results from
    other search engines and directories
  • Do not gather web pages, build indexes, accept
    URL additions, classify or review web sites
  • Some features supported
  • Duplicate hits removal
  • Rank results
  • Selection of search engine(s) to be used

14
Meta Search Tools...
Search using multiple search engines
Search using a meta search tool
15
Meta Search Tools...
  • Meta search tools (remote sites)
  • MetaCrawler (www.metacrawler.com)
  • Ixquick (www.ixquick.com)
  • Dogpile (www.dogpile.com)
  • Meta search tools (local, installable software)
  • Copernic (www.copernic.com)
  • LexiBot (www.completeplanet.com)

16
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17
People Finding Tools
  • Register names and addresses and find e-mail
    addresses
  • Examples
  • Bigfoot (www.bigfoot.com)
  • Peoplesearch (www.peoplesearch.net)
  • Ahoy (ahoy.cs.washington.edu6060/)
  • Four11 (www.four11.com)
  • Switchboard (www.switchboard.com)
  • Whowhere (www.whowhere.lycos.com/)
  • Most search engines also support people searches
    (e.g. Altavista, Google, Yahoo!)

18
Web Search Strategies
  • Search steps
  • Analyze the search topic and identify the search
    terms, their synonyms (if any), phrases and
    Boolean relations (if any)
  • Select the search tool(s) to be used (meta search
    engine, directory, general search engine,
    specialty search engine)
  • Translate the search terms into search statements
    of the selected search engine
  • Perform search
  • Refine the search based on results
  • Visit the actual site(s) and save the information
    (using File-Save option of the browser)

19
  • Google (www.google.com)
  • Enables users to search the Web, images, etc.
  • Features PageRank, caching and translation, an
    option to find similar pages.
  • The focus is developing search technology.
  • Ranked 1 in the world

20
Google
  • Largest Most Popular Search Engine
  • 8 Billion Pages Indexed
  • Very Effective Advanced Search Features
  • Limit searches by domain, ie. Siteedu
  • Limit searches by format, ie. .pdf,
  • Specialized Search Tools
  • Images, Directory, Videos, Books, Scholar, News,
    Blogger

21
How Google works
  • BEFORE you search Crawls pages on the public
    web Copies text images, builds database
  • WHEN you search Automatically ranks pages in
    your results
  • Word occurrence and location on page
  • Popularity - a link to a page is a vote for it
  • 200 factors in all!

22
Limit your search to
  • Web page title intitlehybrid allintitlehybrid
    mileage
  • Website or domain sitewhitehouse.gov global
    warming siteedu global warming
  • File type filetypeppt siteedu global warming
  • Definitions definepixel definedue diligence

23
On the results page
  • Search box (use to modify)
  • Cache
  • Related pages
  • Translate this page

24
Googles other databases
25
Searching for Pictures
  • Searching for images is easy!
  • From the main page of the search engine, select
    images or pictures before entering your search
    term.

26
  • Google Scholar (scholarly literaturearticles,
    books)
  • Google Books (books)
  • Google Directory (handpicked specific topical
    sites)

27
  • Beyond Google
  • Take advantage of human selectivity Librarians
    Internet Index InfoMine Google Custom Search
    Engines (CSE)

28
Thank You!
29
Web Directories/ Guides...
  • Most web directories support searching within
    categories and descriptions, in addition to
    browsing
  • Advantages
  • Access to high quality sources
  • Do not contain redundant links
  • Faster access to sources
  • Disadvantages
  • One needs to be aware of such directories/ guides
  • May not be up-to-date
  • May not be exhaustive
  • Categories (subject hierarchy) varies across
    directories

30
Web Directories/ Guides...
  • When to use web directories/ guides?
  • For broad/ general topics where keyword searching
    on search engines retrieves too many irrelevant
    sites
  • When you want a few highly relevant sites and
    intention is not exhaustive/ comprehensive search
  • When not to use web directories/ guides?
  • For concept/ keyword searches
  • Search terms are distinctive
  • Effective directory/ guide usage
  • Take advantage of the sub-search within
    categories, supported by most directories/ guides
  • Join their mailing lists for automatic updates on
    new sites

31
Web Search Engines...
  • The search engines provide a forms-based search
    interface for entering the queries
  • Support simple and advanced search interfaces
  • Search results are returned in the form of a list
    of web sites matching the query
  • Some key features supported
  • Phrase searching ( double quotes)
  • Boolean searching (AND, OR, NOT)
  • Implied Boolean Term inclusion (), term
    exclusion (-)

32
Web Search Engines
  • Key features
  • Proximity searches (NEAR, ADJ, BEFORE, AFTER)
  • Use of parentheses to group search terms
  • Truncation searches (industr)
  • Field-specific searching (Title, URL, Text)
  • Natural language queries (Why is the sky blue?)
  • Relevance ranking of search results
  • Number of search terms
  • Number of times each search term occurs
  • Proximity of search terms
  • Location of search terms (title, text)

33
Web Search Engines
  • Key features
  • Sub-searching (searching within retrieved
    records)
  • Case sensitivity
  • Limit by language
  • Limit by age of documents
  • Limit by audio, video and image type
  • Translation of search results (title and
    description)
  • Limit by domain, host

34
Web Search Engines...
  • Example tutorials
  • Finding Information on the Internet A tutorial
    (www.lib.berkeley.edu/TeachingLib/Guides/Internet/
    FindInfo.html)
  • How to search the world wide web A tutorial for
    beginners and non-experts. David P. Habib and
    Robert L. Balliot. September, 1999
    (204.17.98.73/midlib/tutor.htm)

35
Web Search Engines...
  • Advantages of search engines
  • Best suited for complex keyword/ concept searches
  • Control over search search terms can be combined
    as required
  • Searches can be limited to period of time,
    fields, source type,etc.
  • Currency of information, made possible by regular
    addition by web spiders
  • Exhaustive information can be retrieved (with
    lots of patience!)
  • Disadvantages
  • Time consuming
  • False positives
  • Search engines vary in terms of search
    techniques/ syntax
  • Dead links, redundant links (same document gets
    displayed)
  • Spamming (salting of pages)
  • Higher ranking of paying sites

36
Web Search Engines...
  • Limitations of web search engines
  • Poor retrieval effectiveness (relevance) as
    little vocabulary control is exercised by web
    site developers and the index engines
  • Different search engines return different search
    results due to the variation in indexing and
    search process (40 non-overlap)
  • None of the search engines come close to indexing
    the entire web, much less the entire Internet.
    Content not indexed
  • PDF documents
  • Content that requires log in
  • Databases searched using CGI programs
  • Web content on intranets behind fire walls

37
Top Sites
  • The top sites on the web, ordered by Alexa
    Traffic Rank.
  • 1. Google
  • 2. Facebook
  • 3. Youtube
  • 4. Yahoo
  • 5. Live
  • 6. Baidu
  • 7. Wikipedia
  • 8. Blogger
  • 9. MSN
  • 10. Tencent
  • 11. Twitter

38
- Enables users to search the Web, images, etc.
- Features PageRank, caching and translation,
an option to find similar pages. - The focus
is developing search technology. - Ranked 1 in
the world according to the three- month Alexa
traffic rankings.
Google
39
Yahoo! 
  • yahoo.com
  • Personalized content and search options.
    Chatrooms, free e-mail, clubs, and pager.
  • Ranked 4 in the world
  • The site is in the Web Portals category.

40
Wikipedia 
  • wikipedia.org
  • An online collaborative encyclopedia.
  • Wikipedia is ranked 7 in the world
  • It has been online for at least nine years.
  • The site's audience tends to be users who browse
    from school and work

41
Meta Search Tools...
  • When to use meta search tools?
  • Need to be used cautiously
  • Good for simple searches, particularly if search
    terms are distinctive or unique
  • Good for testing with a few keywords and find
    which individual search engine returns good
    results
  • Good for quick and dirty searching if you are
    in a hurry and want to find a few relevant sites
    quickly
  • For complex searches, involving many search
    terms, Boolean logic, etc., it is better to use
    individual search engines

42
Meta Search Tools...
  • Advantages
  • Query can be run across multiple search engines
  • User needs to learn only the search interface of
    the meta search tool
  • Better results retrieves top-ranking pages from
    individual search engines
  • Disadvantages
  • Unique features of individual search engines is
    lost
  • Not exhaustive use only top results returned by
    search engines

43
People Finding Tools
  • Using people finding tools
  • Person should have registered in the tool(s)
  • Searcher should know both surname and first name,
    else too many names will be retrieved
  • Bias for U.S. based people
  • Often, required e-mail cannot be retrieved
    through these tools
  • Alternatively, any search engine may be used
    (phrase search using persons name)
  • If persons affiliation is known, Yahoo!
    Directory may be used to locate the institution
    and e-mail

44
Web Search Strategies
  • Tips for effective web searching
  • Broad or general concept searches start with
    directory-based services (want a few highly
    relevant sites for a broad topic)
  • Highly specific or topics with unique terms/ many
    concepts use the search tools
  • Go through the help pages of search tools
    carefully
  • Gather sufficient information about the search
    topic before searching
  • Spelling variations, synonyms, broader and
    narrower terms
  • Use specific keywords, rare/unusual words are
    better than common ones

45
Web Search Strategies...
  • Tips for effective web searching
  • Prefer phrase adjacency searching to Boolean
    (stuffed animal than stuffed and animal)
  • Use as many synonyms as possible - search engines
    use statistical retrieval methods and produce
    better results with more query words
  • Avoid use of very common words (e.g., computer)
  • Enter search terms in lower case. Use upper case
    to force exact match (e.g. Light Combat
    Aircraft, LCA)
  • Use More like this option, if supported by the
    search engine (e.g. Excite, Google)

46
Web Search Strategies...
  • Tips for effective web searching
  • Repeat the search by varying search terms and
    their combinations try this on different search
    tools
  • Enter most important terms first - some search
    tools are sensitive to word order
  • Use the NOT operator to exclude unwanted pages
    (e.g. bio-data, resumes, courses)
  • Go through at least 5 pages of search results
    before giving up the scan
  • Select 2 or 3 search tools and master the search
    techniques

47
Sample Web Searches
  • Companies dealing with polymers
  • Do not use search engines (too many irrelevant
    hits)
  • Use directory sources (e.g. www.yahoo.com)
  • Follow the categories
  • Business and Economy
  • Business-to-Business
  • Chemicals
  • Do a sub-search on Polymers
  • Use specialty search engines (e.g.
    www.bizweb.com)

48
Guides to Search Tools
  • www.beaucoup.com (guide to 2,000 search engines,
    indices and directories)
  • www.searchpower.com (a very comprehensive search
    engine directory - claims over 16,000 search
    engine listings!)
  • www.123go.com/drw/search/search.htm (Dr.
    Websters Big Page of Search Engines )
  • www.finderseeker.com (The search engine of search
    engines)
  • www.virtualfreesites.com (Over 1,000 specialised
    search engines)

49
Keeping Current
  • AskScott (www.askscott.com) Provides a very
    comprehensive tutorial on search engines
  • SearchEngineWatch (www.searchenginewatch.com) The
    site offeres information about new developments
    in search engines and provides reviews and
    tutorials.
  • Botspot (www.botspot.com) Collection and guide
    to variety of bots (intelligent agents)

50
Web Search Engines...
  • Demonstration of search engines
  • Fastsearch (www.alltheweb.com)
  • Altavista (www.altavista.com)
  • Google (www.google.com)
  • Northernlight (www.northernlight.com)

51
Meta Search Tools...
  • Demonstration
  • MetaCrawler (www.metacrawler.com)
  • Ixquick (www.ixquick.com)
  • Dogpile (www.dogpile.com)
  • ProFusion (www.profusion.com)

52
Sample Web Searches...
  • Web pages related to Light Combat Aircraft
  • Keywords are unique
  • Use Search Tools (e.g. www.altavista.com)
  • Search for Light Combat Aircraft (phrase search
    in simple search interface)
  • Use of double quotes will force the search engine
    to consider the set of keywords as a phrase
  • Search can be limited to specific dates
  • More refined search in advanced search interface
    Light Combat Aircraft AND India

53
Sample Web Searches...
  • Web sources related to simulation or modeling of
    activated sludge process
  • This is a concept search - search tools are
    better
  • Using Altavista, the query may be submitted as
  • (simulat OR model) AND activated sludge
    process
  • Note use of to cover word variations like
    simulated, simulate, models, etc.
  • Note use of phrase form for activated sludge
    process
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