We present Opal, a framework for interactively locating missing web pages (http status code 404). Opal is an example of \"in vivo\" preservation: harnessing the collective behavior of web archives, commercial search engines, and research projects for the purpose of preservation. Opal servers learn from their experiences and are able to share their knowledge with other Opal servers using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). Using cached copies that can be found on the web, Opal creates lexical signatures which are then used to search for similar versions of the web page. Using the OAI-PMH to facilitate inter-Opal learning extends the utilization of OAI-PMH in a novel manner. We present the architecture of the Opal framework, discuss a reference implementation of the framework, and present a quantitative analysis of the framework that indicates that Opal could be effectively deployed.
","abstract_html":"<p>We present Opal, a framework for interactively locating missing web pages (http status code 404). Opal is an example of "in vivo" preservation: harnessing the collective behavior of web archives, commercial search engines, and research projects for the purpose of preservation. Opal servers learn from their experiences and are able to share their knowledge with other Opal servers using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). Using cached copies that can be found on the web, Opal creates lexical signatures which are then used to search for similar versions of the web page. Using the OAI-PMH to facilitate inter-Opal learning extends the utilization of OAI-PMH in a novel manner. We present the architecture of the Opal framework, discuss a reference implementation of the framework, and present a quantitative analysis of the framework that indicates that Opal could be effectively deployed.</p>","abstract_has_math":false,"creators":["Harrison, Terry L."],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Thesis","degree_discipline":"Computer Science","degree_department":null,"school":null,"contributors":["Michael L. Nelson","Johan Bollen","Ravi Mukkamula"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2005,"date_issued":"2005-07-01T07:00:00Z","date_published":"2005-07-01T07:00:00Z","updated_at":"2026-07-24T03:34:02Z","subjects":["Computer network resources","Digital preservation","Opal servers","OAI-PMH","Web archives","Web sites","Computer Sciences","Digital Communications and Networking"],"languages":[],"rights":["In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
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