2. A computer-implemented method for generating page rankings using a user access log, comprising: segmenting the user access log into browsing sessions; extracting implicit links from the browsing sessions; generating an implicit links graph from the extracted implicit links; updating the implicit links graph using two-item sequential patterns obtained by filtering ordered pairs of implicit links; re-ranking initial search results using the updated implicit links graph to obtain page rankings; and displaying the page rankings to a user; wherein the implicit links graph is a weighted direct graph that is described by the equation G′=(V,E′), where V is a set of vertices representing all pages in a search space and E′ encompasses a set of implicit links between the pages.
2. A computer-implemented method for generating page rankings using a user access log, comprising: segmenting the user access log into browsing sessions; extracting implicit links from the browsing sessions; generating an implicit links graph from the extracted implicit links; updating the implicit links graph using two-item sequential patterns obtained by filtering ordered pairs of implicit links; re-ranking initial search results using the updated implicit links graph to obtain page rankings; and displaying the page rankings to a user; wherein the implicit links graph is a weighted direct graph that is described by the equation G′=(V,E′), where V is a set of vertices representing all pages in a search space and E′ encompasses a set of implicit links between the pages. 8. The computer-implemented method of claim 2 , further comprising defining a generative model for the user access log based on the implicit links graph.