From Wikipedia, the free encyclopedia

Federated Search is an emerging feature of automated, web based library and information retrieval systems. It is also often referred to as a portal, as opposed to simply a web-based search engine.

Contents 1 Purpose 2 The process 3 Implementation 4 See also 5 External links

As described by Peter Jacso, (2004), Federated searching consists of (1) transforming a query and broadcasting it to a group of disparate databases with the appropriate syntax, (2) merging the results collected from the databases, (3) presenting them in a succinct and unified format with minimal duplication, and (4) providing a means, performed either automatically or by the portal user, to sort the merged result set. In traditional search engines, such as Google, only sources that have been indexed by the search engine’s crawler technology can be searched, retrieved and accessed. The large volume of documents housed in databases is not open to traditional Internet search engines because of limitations in crawler technology. Federated searching resolves this issue by the technique described above and makes these Deep Web documents searchable without having to visit each database individually.

Federated search implements a computer program that allows users to access multiple data sources with a single query string located within a single interface. The user enters a search query in the portal interface’s search box and the search string is sent to every individual database that is incorporated into the portal or federated search list. This must be programmed by the portal owner. Federated search systems either rely upon vendors to create commercial portals, or they rely upon government or other organizations to provide open access portals. How federated search is implemented depends upon which of the two types of organizations are providing the portal.

Generally speaking federated search portals, either commercial or open access, will include among the federated search list public access Bibliographic databases, public access web-based library catalogues, known as OPACs, web based search engines like Google and/or open access, government operated, or corporate data collections. These individual data sources send back to the portal's interface a list of results from the search query. The user can review this hit list. Some portals will merely screen scrape the actual database results and not directly allow a user to enter the data source's application. More sophisticated ones will de-dup the results list by merging and removing duplicates. There are additional features available in many portals, but the basic idea is the same: to improve the accuracy and relevance of individual searches as well as reduce the amount of time required to search for resources.

This process allows federated search some key advantages when compared with existing crawler based search engines. Federated search need not place any requirements or burdens on owners of the individual data sources, other than handling increased traffic. Federated searches are inherently as current as the individual data sources, as they are searched real time.

One application of federated searching is the meta-search engine; however, this is not a complete solution as many documents are not currently indexed. This is known as the the invisible web. Many more information sources are not yet stored in electronic form. Google Scholar is an example of a project trying to address this.

When the search vocabulary or data model of the search system is different from the data model of one or more of the foreign target systems the query must be translated into the each of the foreign target systems. This can be done using simple data-element translation or may require semantic translation.

Some currently popular software for the use in a library context, are WebFeat and the similarly named Web Feet, both used for searching bibliographic databases by the Z39.50 protocol.

Many public and academic libraries also utilize Auto-Graphics' federated search solution AGent Search

Another popular provider is MetaLib - see http://www.exlibrisgroup.com/metalib.htm

Another popular provider is Serials Solutions - see http://www.serialssolutions.com/promotion/centralsearch.asp

Another popular provider is Deep Web Technologies - see http://www.deepwebtech.com

A popular implementation of federated search is Science.gov - see http://www.science.gov

• Metasearch engine
• Funnelback
• Aggregator