Microsoft Technology Licensing, LLC

Lei Qi

Hang Li

Bin Gao

Tie-Yan Liu

Lei Yang

Ranking documents based on a series of web graphs collected over time is provided. A ranking system provides multiple transition probability distributions representing different snapshots or times. Each transition probability distribution represents a probability of transitioning from one document to another document within a collection of documents using a link of the document. The ranking system determines a stationary probability distribution for each snapshot based on the transition probability distributions for that snapshot and the stationary probability distribution of the previous snapshot. The stationary probability distributions represent a ranking of the documents over time.

Ranking documents based on a series of document graphs

A calculate importance system calculates the global importance of a web page based on a 'mean hitting time.' Hitting time of a target web page is a measure of the minimum number of transitions needed to land on the target web page. Mean hitting time of a target web page is an average number of such transitions for all possible starting web pages. The calculate importance system calculates a global importance score for a web page based on the reciprocal of a mean hitting time. A search engine may rank web pages of a search result based on a combination of relevance of the web pages to the search request and global importance of the web pages based on a global hitting time.

Calculating global importance of documents based on global hitting times

A method and system for determining temporal importance of documents having links between documents based on a temporal analysis of the links is provided. A temporal ranking system collects link information or snapshots indicating the links between documents at various snapshot times. The temporal ranking system calculates a current temporal importance of a document by factoring in the current importance of the document derived from the current snapshot (i.e., with the latest snapshot time) and the historical importance of the document derived from the past snapshots. To calculate the current temporal importance of a web page, the temporal ranking system aggregates the importance of the web page for each snapshot.

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Lei Qi