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Metadata

introduction of. Ahmed I. Deeb Dr. Anwar Mousa.  presenter.  instructor. Metadata. University Of Palestine-2009. . What is Metadata?. What is a search engine?. Why isn't an Internet search engine good enough?. Why use metadata?. Contents. Which Metadata schema?.

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Metadata

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  1. introduction of Ahmed I. Deeb Dr. Anwar Mousa  presenter instructor Metadata University Of Palestine-2009

  2. What is Metadata? What is a search engine? Why isn't an Internet search engine good enough? Why use metadata? Contents Which Metadata schema? Example of metadata

  3. Metadata is structured data which describes the characteristics of a resource. It shares many similar characteristics to the cataloguing that takes place in libraries, museums and archives. The term "meta" derives from the Greek word denoting a nature of a higher order or more fundamental kind. What is Metadata?

  4. What is Metadata? A metadata record consists of a number of pre-defined elements representing specific attributes of a resource, and each element can have one or more values. Below is an example of a simple metadata record:

  5. What is Metadata? • Each metadata schema will usually have the following characteristics: • a limited number of elements • the name of each element • the meaning of each element

  6. What is Metadata? Typically, the semantics is descriptive of the contents, location, physical attributes, type (e.g. text or image, map or model) and form (e.g. print copy, electronic file). Key metadata elements supporting access to published documents include the originator of a work, its title, when and where it was published and the subject areas it covers. Where the information is issued in analog form, such as print material, additional metadata is provided to assist in the location of the information, e.g. call numbers used in libraries. The resource community may also define some logical grouping of the elements or leave it to the encoding scheme. For example, Dublin Core may provide the core to which extensions may be added.

  7. What is Metadata? Some of the most popular metadata schemas include: Dublin Core AACER2 (Anglo-American Cataloging Rules) GILS (Government Information Locator Service) EAD (Encoded Archives Description) IMS (IMS Global Learning Consortium) AGLS (Australian Government Locator Service)

  8. What is Metadata? While the syntax is not strictly part of the metadata schema, the data will be unusable, unless the encoding scheme understands the semantics of the metadata schema. The encoding allows the metadata to be processed by a computer program. Important schemes include: HTML (Hyper-Text Markup Language) SGML (Standard Generalized Markup Language) XML (eXtensible Markup Language) RDF (Resource Description Framework) MARC (MAchine Readable Cataloging) MIME (Multipurpose Internet Mail Extensions)

  9. What is Metadata? • Metadata may be deployed in a number of ways: • Embedding the metadata in the Web page by the creator or their agent using META tags in the HTML coding of the page. • As a separate HTML document linked to the resource it describes. • In a database linked to the resource. The records may either have been directly created within the database or extracted from another source, such as Web pages.

  10. What is Metadata? The simplest method is for Web page creators to add the metadata as part of creating the page. Creating metadata directly in a database and linking it to the resource, is growing in popularity as an independent activity to the creation of the resources themselves. Increasingly, it is being created by an agent or third party, particularly to develop subject-based gateways.

  11. What is a search engine? Search engines, such as Google and HotBot, consist of a software package that crawls the Web, extracts and organizes the data in a database. People can then submit a search query using a Web browser. The search engine locates the appropriate data in the database and displays it via the browser. Of course, the Web being the Web, things change very rapidly. For example, in October 2002, Yahoo made a giant shift to using Google's crawler-based listings for its main results.

  12. What is a search engine? Search engines have three major elements: The spider, also called the crawler, harvester, robot or gatherer. The spider visits a Web page, reads it, and then follows links to other pages within the site. The spider returns to the site on a regular basis, such as every month or two, to look for changes. The index. Everything the spider finds goes into the index. The index is like a giant book containing a copy of every web page that the spider finds. If a web page changes, then this book is updated with new information. Search engine software. This is the program that sifts through the millions of pages recorded in the index to find matches to a search and rank them in order of what it believes is most relevant.

  13. Why isn't an Internet search engine good enough? • The Web has become now very easy to publish information, but it is becoming more difficult to find relevant information. • The Working Group on Government Information Navigation outlined the problems with Internet search engines: • Relevant information can be missed because sites contain types of resource in addition to HTML text (e.g. images, databases, PDF documents). • The search engines frequently do not harvest every page on a site, but often only the top two or three hierarchical levels, thus missing significant documents which, on larger and more complex sites, may be located in lower levels of the hierarchy. • Irrelevant information can be retrieved because the search engine has no means (or very few means) of distinguishing between important and incidental words in the document text.

  14. Why isn't an Internet search engine good enough? The introduction of the <META> element as part of HTML coding, was in part, an attempt to encourage search engines to extract and index more structured data, such as description and keywords. However, search engines are rather easy to recognize <META> tags.

  15. Why use metadata? • A more formal definition of metadata : • Metadata is data associated with objects which satisfies their potential users of having full advance knowledge of their existence or characteristics. • While the primary aim of metadata is to improve resource discovery, metadata sets are also being developed for other reasons, including: • administrative control • security • personal information • management information • content rating • rights management • preservation

  16. Which Metadata schema? There are literally hundreds of metadata schemas to choose from and the number is growing rapidly, as different communities seek to meet the specific needs of their members. Recognizing the need to answer the question of how can a simple metadata record be defined that sufficiently describes a wide range of electronic documents, The Online Computer Library Center (OCLC) of which the University of Queensland Library combined with the National Center for Supercomputing Applications (NCSA) to sponsor the first Metadata Workshop in March, 1995 in Dublin, Ohio.

  17. Which Metadata schema? The primary outcome of the workshop was a set of 13 elements (subsequently increased to 15) named the Dublin Metadata Core Element Set (known as Dublin Core). Dublin Core was proposed as the minimum number of metadata elements required to facilitate the discovery of document-like objects in a networked environment such as the Internet. Next is a summary of the elements in Dublin Core. The metadata elements fall into three groups which roughly indicate the class or scope of information stored in them: (1) elements related mainly to the content of the resource. (2) elements related mainly to the resource when viewed as intellectual property. (3) elements related mainly to the physical characteristic of the resource.

  18. Which Metadata schema?

  19. Example of metadata Below is an example of a Dublin Core record for a short poem, encoded as part of a Web page using the <META> tag: <HTML> !4.0!<HEAD><TITLE>Song of the Open Road</TITLE><META NAME="DC.Title" CONTENT="Song of the Open Road"><META NAME="DC.Creator" CONTENT="Nash, Ogden"><META NAME="DC.Type" CONTENT="text"><META NAME="DC.Date" CONTENT="1939"><META NAME="DC.Format" CONTENT="text/html"><META NAME="DC.Identifier" CONTENT="http://www.poetry.com/nash/open.html"></HEAD><BODY><PRE>I think that I shall never seeA billboard lovely as a tree.Indeed, unless the billboards fallI'll never see a tree at all.</PRE></BODY></HTML>

  20. Thank You! Thank You! Questions?

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