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  • Each of these stages will be explained in more detail.
  • These are some of the ways a query can be constructed and have been used by librarians for a long time when searching online bibliographic databases.
    Boolean operators can be used to broaden or narrow a search, to focus it more precisely. For example:
    AND requires all the words to be present in your results - the example would bring back documents that contain both words.
    OR means that documents containing either of the words will be retrieved. This will broaden the search but the relevancy will decrease.
    NOT excludes results containing a particular word.
    NEAR requires results to contain words within a certain distance of each other.
    Field Searching enables you to search in particular parts of a document, for example its title (point out that title searching is something different on the Web- the title of a web page is what appears in the bar at the top of the browser window). This should increase the relevance of the search.
    Phrase searching allows you to search for words to appear exactly together in the order you have stated. Useful for real names, companies, songs etc.
    Truncation enables you to find different variations on a word such as the plurals, or similar words with differing endings such as lion, lioness etc.
    Parentheses allow you to group parts of your search together to allow more complex queries involving different concepts.
  • Example of how you might structure a specific search using Boolean logic, phrase searching and truncation.
    Notice the use of phrases, synonyms and parentheses to group concepts. Truncation to cover plurals. Also inclusion of alternative US spelling. (Other possible keywords include cancer, telephone*) .
    (Depending on time could get participants to suggest a search and construct a query to try out).
    Constructing this type of query is the most effective way of constructing a search. (possible demo of search on AltaVista advanced query). But it's not that simple...
  • 1. This search may work well on the AltaVista advanced search, but not all search engines support such complex queries. Also such detail searching not appropriate on directories like Yahoo! where broad searches are better (Yahoo! doesn't support Boolean anyway). Metasearch engines do not support complex searches very well as they have to pass the queries on to other search engines that support different features.
    2. Even if they do support these features, the way of constructing them may not be the same eg. in AltaVista and Excite, have to use AND NOT instead of just NOT. More on this on next slide.
    3. Capitalisation - might have noticed our search terms were all in lower case- some search engines are case sensitive and some are not. Those that are case-sensitive (eg AltaVista, HotBot) are only case sensitive when upper-case is used - they will search for both upper and lower when lowercase is used. Therefore, unless searching for a proper name, it is best to use lower case.
    4. Be aware when constructing a search that some very common words are treated as stop words eg: a, the, from, etc, but sometimes words like 'web' are stop words. This means they are not indexed in your search. Some search engines will let you over-ride this, others won't (eg selecting a natural language search in Lycos lets you include stop words).
  • So what do search engines support and what other features do they have? (demo as many as you like!)
    Complex queries. As previously mentioned, many of these features are supported, but its a question of finding out which search engine supports what and how it does it. Eg some require Boolean commands to be in capitals (Excite) whereas others are case insensitive. There may also a problem with combining certain types of feature or knowing when it can be used (eg Boolean can only be used in the Advanced search on AltaVista).
    Some things are supported almost universally - according to SearchEngineWatch only LookSmart doesn't support the use of + and - and ""
    + and - signs : used either to require a word to be present or to exclude a word. Performs a basic type of Boolean search. Note that signs are placed in front of the words with no spaces. The plus sign should not simply be used in between words in place of the Boolean AND.
    Automatic phrase searching - most dramatic at AltaVista. When search terms are entered AltaVista compares them to its database of several million phrases and if it recognises your terms as an existing phrase then it will automatically be searched for as a phrase.
    Automatic stemming - be aware that some search engines will automatically search for variations of word endings so truncation may not be necessary. Muscat search engine (which powers EuroFerret) does this.
    Field searching and limits - can be used in many different ways on the Web. eg the 2 two most common:Title: searches within the title of a document (which is something different on the Web - explain).
    URL: search for the word in the URL.
  • Search engines use relevancy ranking to sort your results according to how well they think they match your needs. Each document retrieved is given a score, and this is then used to present them in order of relevance. They use a number of criteria for this, including:
    - how many times your chosen words appear in the document
    - where in the document your chosen words appear (title, first paragraph, meta-tags etc.)
    - link popularity is one of the newer features to be used in relevancy ranking algorithms. It uses the idea that a site is likely to be of higher quality if lots of other sites have chosen to link to that site.
    You can use relevancy ranking features to help you screen out the less relevant documents - it is likely that only the first few screens of results will be highly relevant to your enquiry.

Transcript

  • 1. 1 Dave Inman Project ResearchProject Research
  • 2. 2 Process of ResearchProcess of Research Literature searchLiterature search Refine searchRefine search Literature reviewLiterature review More focusMore focus
  • 3. 3 TimescaleTimescale  Start early in life of project  Intensive in months 1-2  On-going throughout first semester  Further research in semester 2
  • 4. 4 SourcesSources  Past projects  Books  Library  Friends  Tutors  Journals / magazines  Library  Web  Tutor / friend recommended sites  Search engines
  • 5. 5 Past projectsPast projects
  • 6. 6 LISA (www.lisa.sbu.ac.uk)LISA (www.lisa.sbu.ac.uk)
  • 7. 7 Search for JournalsSearch for Journals
  • 8. 8 Journals in ComputingJournals in Computing
  • 9. 9 Electronic JournalsElectronic Journals
  • 10. 10 Database Cross- Searching  Many subjects are cross-disciplinary and so the ability to search across several databases is a useful time-saver.  http://www.sosig.ac.uk/
  • 11. 11 Library catalogLibrary catalog
  • 12. 12 Web Search EnginesWeb Search Engines Two kinds: Manually updated (e.g. Yahoo!) Auto updated (e.g. AltaVista)
  • 13. 13 Links to Search EnginesLinks to Search Engines http://www.sbu.ac.uk/home/gateways.shtmlhttp://www.sbu.ac.uk/home/gateways.shtml
  • 14. 14 Links to Search EnginesLinks to Search Engines http://www.sbu.ac.uk/home/gateways.shtmlhttp://www.sbu.ac.uk/home/gateways.shtml
  • 15. 15 Search Engine Display Chart
  • 16. How can you searchHow can you search more effectively?more effectively?  Plan your search in advance  Become familiar with advanced search concepts  Learn to use search engine features & search syntax  Review and refine your searches
  • 17. Overview of SearchOverview of Search ConceptsConcepts  Boolean Operators - AND, OR, NOT  lions AND tigers  cheetahs OR jaguars NOT cars  Field and phrase searching  “Safari Corporation Inc.”  title: "Safari Corporation Inc.”  Truncation using wildcard symbol  lion*  Parentheses  (lions OR tigers) AND (zoos OR parks)
  • 18. Example SearchExample Search Topic The possible link between mobile phones and brain tumours ("mobile phone*" OR "cellular phone*") AND ("brain tumour*" OR "brain tumor*")
  • 19. Search Engine IssuesSearch Engine Issues  Complex Boolean searches do not work on all search engines  Different search engines have different features and syntax  Case sensitivity - use lowercase unless searching for a proper name
  • 20. Searching FeaturesSearching Features  Complex queries (Boolean, parentheses, truncation etc) supported to varying degrees  Almost universal:  Use of + and - signs eg +jaguars -cars  Phrase searching using double quotes " "  Stemming - sometimes automatic  Field searching and limits  title, url, date, language, domain  May be in separate "advanced" search page  May be in form of menus or check-lists
  • 21. Relevancy RankingRelevancy Ranking Factors used to rank results:  Number of occurrences of word(s) on page  Where the word(s) occur ie more important if found in title or at top of page  Page contains all words  Words found near or next to each other  Link popularity - sites ranked higher if they have lots of other sites linking to them
  • 22. 22 Intelligent Agents: WiseWire An ‘agent’ you can train with your preferences http://wires.wisewire.com/
  • 23. 23 GoogleGoogle  Uses citations or "backlinks".  A page is ranked as important if lots of other pages point to it.  A page will be ranked more highly if lots of other pages with high ranking point to it.  Google! Looks at over a billion links.  Also try Google Print (http://print.google.com/) for finding info in books  Also Google Scholar (http://scholar.google.com/) for academic work
  • 24. 24 http://www.zotero.org/http://www.zotero.org/
  • 25. 25 ReferencesReferences Chapter 4 of : Dawson, C.W. - Computing projects: A student's guide - Prentice Hall 2000 Parts ©Netskills,University of Newcastle http://www.netskills.ac.uk/ Web tutorial on ICT research (http://snurl.com/projsources)