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Using Domain Ontology for Semantic Web Usage Mining and Next

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					                                                         Using Domain Ontology for Semantic
                                                       Web Usage Mining and Next Page Prediction
                                           Nizar R. Mabroukeh                                                                                                                                                        Christie I. Ezeife
                                                                                                                          University of Windsor, Canada
       Introduction
         Semantic information drawn from a web application’s domain knowledge is integrated into all phases of the web usage mining process (preprocessing, pattern discovery, and
      recommendation/prediction). The goal is to have an intelligent semantics-aware web usage mining framework (SemAware). This is accomplished by using semantic information in the
      sequential pattern mining algorithm to prune the search space and partially relieve the algorithm from support counting. In addition, semantic information is used in the prediction phase
      with low order Markov models, for less space complexity and accurate prediction, that will help solve ambiguous predictions problem.

       SemAware
         A complete generic framework for web usage mining, that utilizes an underlying domain ontology available with web applications, on which any sequential pattern mining algorithm
       and markov model can fit.



                                                                                                                                                                                                                                                             Domain
                                                                                                                                                                               g
                                                                                                                                                Semantics-aware Web Usage Mining                                                                             Ontology
                                                                                              Preprocessing




                                                                                                                       Server Web Log
                                                                                                                       Server
                                                                                                                         r                                                               Domain Ontology
                                                                                                                                                                                                Ontolog                      i
                                                                                                                                                                                                                        Domain
                                                                                                                                                                                                                       Knowledge
            Semantically Annotated Web Pages                                                                                                                                        Semantics
               in e-Commerce application
                                                          b                                                                                                          Web Log
                                                                                                                                                                         c
                                                                                                                                                                   Preprocessing
                                                                                                                                                                   Preprocessing
                                                                   e
                                                                                                   Pattern Discovery




                                                                                                                                                                             Transactions
                                                                                                                                                                                   c
                                                                                                                                                          Semantic-rich User Transactions        Semantic Distance
                                                                                                                                                                                                     Matrix
                                                S                  c        E                                 1st-Order
                                                                                                                        Markov    Model                Integrated Sequential Patterns Mining
                                                                                                                                                                 and Markov Model
                                                                   d

                                                           a                                                                                                                  b
                                                                                                                                                                             Objects
                                                                                                                                                              Mined Semantic Objects
                                                                                                                                   r
                                                                                                                       Semantic-aware Markov Transition Matrix
                                                                                      Recommendat-
                                                                                      Recommendat-




                                                                                                                                                                    r Association
                                                                                                                                                                       A
                                                                                                                                                       Semantics-aware Association Rules
                                                                                          ion




                                                                                                                                                                                                                     vs.
                                                                                                                                Next Page Request
                                                                                                                                  x                           Online Recommendation
                                                                                                                                    Prediction
                                                                                                                                      r
                                                                                                                                    Prediction
                                                                                      R




       Semantics-aware Sequential Pattern Mining
          Semantic information from the Semantic Distance Matrix W, is used to prune the search space in any SPM algorithm, without the need
       for support counting. Example here shows SemApJoin generate-and-test procedure for AprioriAll-Sem, a semantics-aware Apriori-based
       SPM. In this case a semantic object o_i is not affixed to the candidate sequence if its semantic distance from the last object in the sequence
       is more than the maximum allowed semantic distance η.
       We constructed GSP-sem and AprioriAll-sem, and experimented with synthetic data sets as well as real web logs, to find out that those two
       algorithms require only 26% of the search space used by their comparable non-semantics-aware SPMs and are 3-4 times faster. More test-
       ing was made on GSP-sem to find the optimal value for η, which was found to be between 3-4, allowing to use only 38% less memory and
       run 2.8 times faster than GSP.




        GSP-sem and AprioriAll-sem execution time (min.) vs. η   GSP-sem and AprioriAll-sem memory usage (KB) vs. η




      Semantics-aware Next Page Request Prediction (Semantic-Rich Markov Models)
         Semantic information can be used in a Markov model as a proposed solution to provide semantically meaningful and ac-
       curate predictions without using complicated All-Kth-order or SMM. The semantic distance matrix M is directly combined
       with the transition probability matrix P of a Markov model of the given sequence database, into a weight matrix W. This
       weight matrix is consulted by the predictor software, instead of P, to determine future page view transitions for caching or
       prefetching.


      Semantic-rich Association Rules
        These are rules that carry semantic information in them, such that the recommendation engine can make better informed decisions. They
      provide more accurate recommendations than regular association rules, by overcoming ambiguous predictions problem (as shown in
      SemAware framework above). Such association rules can also be used with concept generalization, that allows the decision maker to make
      generalizations from frequent user sequences, within the limits of the domain ontology available.

      Conclusion
         As domain knowledge becomes more integrated into the design of web applications of today, and with the advent of OWL and RDF tech-
      nology, web pages can easily be annotated with semantic information. We introduce SemAware, a comprehensive generic framework that in-
      tegrates semantic information into all phases of web usage mining. Semantic information can be integrated into the pattern discovery phase,
      such that a semantic distance matrix is used in the adopted sequential pattern mining algorithm to prune the search space and partially re-
      lieve the algorithm from support counting. A 1st-order Markov model is also built during the mining process, to be used for next page request
      prediction, beside association rules resulting from the pattern discovery phase as a solution to ambiguous predictions problem. In this case
      semantic information is infused into the Markov transition probability matrix to convert it to a matrix of weights for better-informed predic-
      tion, thus providing an informed lower order Markov model without the need for complex higher order Markov models.

For Further Information                                                                                                                                                                                                                   This research is supported by the Natural Science and
                                                                                                                                                                                                                                          Engineering Research Council (NSERC) of Canada
                                                         [cezeife@uwindsor.ca],
Nizar Mabroukeh [mabrouk@uwindsor.ca] or Christie Ezeife [cezeife@uwindsor.ca], WODD Lab, School of Computer Science, University of Windsor.                                                                                              under an operating grant (OGP-194134) and a Uni-
401 Sunset Ave.                                                                                                                                                                                                                           versity ofWindsor grant.

Windsor, Ontario N9B 3P4                                                                                                                                                                                                                  Designed by Nizar Mabroukeh with Adobe Illustrator CS, 2009

				
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