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CPSC 335

CPSC 335. Application of Trees Dr. Marina Gavrilova Computer Science University of Calgary Canada. Applications of Trees. for Information Storage - Database for Searching - Web search (google, yahoo, msn) - Searching in external memory (string B-tree)

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CPSC 335

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  1. CPSC 335 Application of Trees Dr. Marina Gavrilova Computer Science University of Calgary Canada

  2. Applications of Trees • for Information Storage - Database • for Searching - Web search (google, yahoo, msn) - Searching in external memory (string B-tree) • in Operating System - Page Segmentation • in Games Design • for Visualization

  3. Applications of Trees

  4. Applications of Trees

  5. Applications of Trees

  6. Applications of Trees Applications of Adaptive Trees • for Image retrieval • for Audio coding • in Routing protocol application • for MPEG decoding • in Natural language processing

  7. Google Search • Has been in the search game a long time, and saw the web graph when it was much cleaner than the current web graph • Is much better than the other engines at determining if a link is a true editorial citation or an artificial link • Looks for natural link growth over time • Heavily biases search results toward informational resources • Trusts old sites way too much • a page on a site or subdomain of a site with significant age or link related trust can rank Auch better than it should, even with no external citations • Have aggressive duplicate content filters that filter out many pages with similar content • Crawl depth determined not only by link quantity, but also link quality. Excessive low quality links may make your site less likely to be crawled deep or even included in the index. • Things like cheesy off topic reciprocal links are generally ineffective in Google when you consider the associated opportunity cost

  8. MSN Search • New to the search game • Is bad at determining if a link is natural or artificial in nature • Due to sucking at link analysis they place too much weight on the page content • Their poor relevancy algorithms cause a heavy bias toward commercial results • New sites that are generally untrusted in other systems can rank quickly in MSN Search • Things like cheesy off topic reciprocal links still work great in MSN Search

  9. Yahoo Search • Been in the search game for many years. • Is better than MSN but nowhere near as good as Google at determining if a link is a natural citation or not. • Has a ton of internal content and a paid inclusion program. both of which give them incentive to bias search results toward commercial results • Things like cheesy off topic reciprocal links still work great in Yahoo!

  10. More on Applications of Trees • in Biology - Suffix tree (in Bioinformatics – DNA/RNA prediction) - M-Tree (in Molecular Biology) • in Oceanography - Path Planning • in GIS • in NASA - Astronomical Database (Quad Tree)

  11. Useful Links • B-Tree Animation http://slady.net/java/bt/ • R-Tree Animation http://gis.umb.no/gis/applets/rtree2/jdk1.1/help.html • Animations for Data Structure http://www.csse.monash.edu.au/~dwa/Animations/index.html

  12. Useful Links • Comparing Search Algorithm http://www.seobook.com/relevancy/ • Quadtree for Astronomical Database http://www.adass.org/adass/proceedings/adass94/barrettp.html • Search Engine White Papers http://www.seoexplore.com/search-engine-white-papers.php • String B-Tree http://coblitz.codeen.org:3125/citeseer.ist.psu.edu/cache/papers/cs/3489/http:zSzzSzwww.math.tau.ac.ilzSz~matiaszSzcourseszSzpaperszSzstring_btree.pdf/ferragina98string.pdf

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