Temporal information retrieval in cooperative search engine

In business, the retrieval of up-to-data, or fresh, information is very important. It is difficult for conventional search engines based on a centralized architecture to retrieve fresh information, because they take a long time to collect documents via Web robots. In contrast to a centralized architecture, a search engine based on a distributed architecture does not need to collect documents, because each site makes an index independently. As a result, distributed search engines can be used to retrieve fresh information. However, fast indexing alone is not enough to retrieve fresh information, as support fro temporal information based retrieval is also required. In this paper, we describe temporal information retrieval in distributed search engines. In particular, we propose a content-based comparison method to avoid spamming.