A semantic session analysis method partitioning Web usage logs is presented．Semantic W eb usage log preparation model enhances usage logs with semantic．The M arkov chain

mode1 based on ontology semantic measurement is used to identi．

ing which active session a request should belong to．The corn—

petitive method is applied to determine the end of the sessions．

Compared with other algorithms，more successfu1 sessions are additionally detected by semantic outlier analysis．