Data processing: database and file management or data structures – Database design – Data structure types
Reexamination Certificate
2000-07-27
2003-07-29
Metjahic, Safet (Department: 2171)
Data processing: database and file management or data structures
Database design
Data structure types
Reexamination Certificate
active
06601075
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of data processing, and particularly to a software system and associated method adapted for use within a search engine system, to rank search results based on document quality. This invention pertains, in particular, to a computer software product and algorithm for retrieving and ranking XML documents and their associated document schemas based on the link relationships among them.
BACKGROUND OF THE INVENTION
The World Wide Web (WWW) is comprised of an expansive network of interconnected computers upon which businesses, governments, groups, and individuals throughout the world maintain inter-linked computer files known as web pages. Users navigate these pages by means of computer software programs commonly known as Internet browsers. Due to the vast number of WWW sites, many web pages have a redundancy of information or share a strong likeness in either function or title. The vastness of the WWW causes users to rely primarily on Internet search engines to retrieve information or to locate businesses. These search engines use various means to determine the relevance of a user-defined search to the information retrieved.
A typical search engine has an interface with a search window where the user enters an alphanumeric search expression or keywords. The search engine sifts through its index of web pages to locate the pages that match the user's search terms. The search engine then returns the search results in the form of HTML pages. Each set of search results includes a list of individual entries that have been identified by the search engine as satisfying the user's search expression. Each entry or “hit” includes a hyperlink that points to a Uniform Resource Locator (URL) location or web page.
A search of web pages using keywords, in most cases, returns an over-abundance of search-results. For example, a search for “Harvard” might result in an excessive number of web pages. Search engines face the challenge of ranking these results according to the most definitive pages for the search query. Text-based ranking alone will often miss some pages that are relevant to the search. Of the pages that contain “Harvard,” for example, the web site www.harvard.edu may not be the one that uses the term “Harvard” most often, most prominently, or in any other way that would favor it under a purely text-based ranking function even when it is the most definitive result for a topic-based search query.
One approach to addressing this ranking problem is to exploit the information embedded in the hyperlink structure of WWW pages. Hyperlinks encode a considerable amount of human judgment used by various techniques to determine the authority or quality of a page in a specific context. Exemplary techniques that use algorithms to exploit the hyperlink structure within HTML pages for this purpose are the HITS and CLEVER methods. These algorithms have been implemented in search environments in order to determine the relevance of HTML pages to user-defined search criteria.
The HITS method introduces the notions of “authoritative” and “hub” resources. An authoritative resource (or authority page) is one that contains definitive information about a topic. In other words, in the context of search results, it is a high-quality page. A hub resource (or hub page) is one that contains a large number of hyperlinks that point to authoritative pages. The HITS algorithm is applied to a set of pages returned by a text-based search (a seed set). The goal is to determine the most authoritative pages and best hub pages in the set. To accomplish this goal, the HITS algorithm makes use of the structure of the in-links (the links into a web page) and the out-links (the links out of a web page) of each of the pages within the set. To begin, it counts the number of each page's out-links. In the first iteration, the initial ‘hub’ score of a page is the number of pages linking out of that page, and the initial ‘authority’ score of this page is the number of pages pointing to it. The ‘hub’ score for the next iteration is the sum of the ‘authority’ scores of the out-linked pages and the ‘authority’ score is the sum of the ‘hub’ scores of the in-linked pages. The iterations are continued until satisfactory convergence for the ‘authority’ and ‘hub’ scores is achieved. The pages with the highest ‘hub’ and ‘authority’ scores are identified as the results of the search.
HITS is the definitive algorithm used to find authoritative resources in a hyperlinked environment. The CLEVER method extends the HITS method by taking advantage of the text surrounding hyperlinks. It uses the annotations provided by this text to weight each link and further classify the search results.
A significant portion of the WWW documents today are authored in HTML, which is a mark-up language that describes how to display page information through a web-browser and to link documents up to each other. HTML is an instance of SGML (Standardized Markup Language) and is defined by a single document schema or Document Type Definition (DTD). The document schema puts forth a set of grammatical rules that define the allowed syntactical structure of an HTML document. The schema, or structure of HTML pages, is consistent from page to page. Both the HITS and CLEVER algorithms apply to HTML pages and do not necessarily address documents containing a number of different schemas.
Currently, however, Extensible Markup Language (XML) is gaining popularity. XML, which is a subset of SGML, provides a framework for WWW authors to define schemas for customized mark-up languages to suit their specific needs. For example, a shoe manufacturer might create a “shoe” schema to define an XML language to be used to describe shoes. The schema might define mark-up tags that include “color”, “size”, “price”, “material”, etc. Hence, XML documents written in this shoe language will embed semantic, as well as structural, information in the document. For example, a shoe XML document uses the mark-up tag “color” to indicate that the shoe is “blue”.
One advantage of XML is that it allows the efficient interchange of data from one business to another (or within the business itself. A business may send XML data that conforms to a predefined schema to another business. If the second business is aware of the first business's schema, it may use a computer program to efficiently process the data. To enable this efficient data interchange and processing, XML requires that standard and high-quality schemas be developed and conformed to, by XML documents.
As noted, the XML framework allows for the definition of document schemas, which give the grammars of particular sets of XML documents (e.g. shoe schema for shoe-type XML documents, resume schema for resume-type XML documents, etc.). The XML framework also puts forth a set of structural rules that all XML documents must follow (e.g. open and close tags, etc.). Moreover, it is possible for an XML document to have no associated schema. If a document has an associated schema, the schema must be specified within the document itself or linked to by the document.
Information about the quality of an XML document may be inferred by its conformance with the rules put forth by this XML framework. An XML document is said to be “valid” if it has an associated schema and conforms to the rules of the schema. An XML document is said to be “well-formed” if it follows the general structural rules for all XML documents. Ultimately, a high quality document has a higher probability of being both “valid” and “well-formed” than a low-quality document.
In addition, like HTML documents, XML documents form a hyperlinked environment in which each XML document that has an associated schema provides a link to the schema (if the schema is not defined within the document itself. Moreover, each XML document, using various mark-up structures, such as XLink or XPointer, may link up to other XML structures and XML documents. Unlike the HTML environment, however, the schemas of each hyperlinked document
Huang Anita Wai-Ling
Sundaresan Neelakantan
Al-Hashemi Sana
Kassatly Samuel A.
Metjahic Safet
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