repository: http://code.google.com/p/booksmarkuplanguage/. II. XML AND ITS TECHNOLOGIES. I started with developing a mar
Markup Language for books XML and Semantic Web Approach Rakhi Gupta Department of Computer Science Loyola University Chicago Chicago, IL 60640 Email:
[email protected]
Abstract—There is no such thing as an independent book store any more. Books, like wine, are a mass commodity exploding at a dizzying rate across the world as more and more people are driving up demand for even the most obscure titles no matter where they are published. It is possible to find a little known Brazilian author in a remote shop in Goa as it is for the newest book about Harry Potter. Book club recommendations by national figures like Oprah and Dr Phil also cause sharp spikes in demand and both publishers and sellers have to be able to deal with this information overload. Not only bookstores but other auxiliary sellers and consumers of publishing property2="Feet of Clay" property3="12345"/>
Advantages:
Example2:
1) Multiple Environments: XForms can support multiple environments like mobile phone browsers, audio browsers etc and help in communication between different processes. The labels attached to particular fields in the markup allow other programs to identify them. 2) Internationalization and localization: There are no encoding problems in XForms as they use XML as underlying serialization form [7] and situations where different forms of languages are used; separation of presentation from content comes to rescue because nothing in XForms say how the fields should be laid out. 3) Input Validation: One can validate these forms both on the client as well as the server side as all the client encoding="UTF-8"?>
Let’s Learn Semantic Web in Summers 25.25 23.50 15 Rakhi Gupta 2009-07-25 /rdf:Description> rdf:RDF defines the URI namespace of rdf document and xmlns=http://wwww.bml.net/books/Catalog# is the namespace I created for the books catalog where Catalog signifies the main Class to which books belong. rdf:Description describes the resource and rdf:about provides an absolute URI for the resource. Next we have a resource called Semantic Web which is an instance of class Books. So, the subject node Semantic Web has a rdf:type predicate indicating that they are instances of some type.
to add new personal observations to it then it is easily 23.50 possible without having to agree to a change in schema. Also, the order of properties does not matter in RDF 15.00 unlike XML. 5) Decentralized: It works in a decentralized fashion RDF does not have a > 25.25
Ontologies is a description of relationship between ideas. An XML DTD is also a kind of ontology but it is a restrictive and limited to relationships like parent-of, child-of and attribute-of. A complete ontology can include any arbitrary relationships like is-akind-of, if-then, or even it can model specific ideas like published-by or is-afraid-of. They are described by a markup called RDF.
Dublin Core is a vocabulary used to describe documents or web pages. I used Dublin Core prdicates in above example to describe the creator as well as the creation date of the RDF document. RDF validator is being used to validate the RDF documents which is provided by www.w3.org at www.w3.org/RDF/validator and it helped me to know if the document is in proper RDF format or not. RDF Schema
Web ontology language used in Semantic Web is OWL [13]which comprises of RDF Schema for organizing information and additional new constructs which could express much more complex and richer relationships. It adds more domain knowledge with the use of cardinality constraints, set operators, various functional properties and enumerations etc. It also describes relationships between classes and use the logic to make deductions. OWL provides a reusable domain knowledge and one could also create new
As we have XML Schema for XML; similarly we have RDF Schema for Semantic Web. RDF Schema is an extension of RDF [12] and it provides a vocabulary which can be used by RDF instance statements. It helps in defining classes and 4
classes based on the existing information quite easily.
OWL: In RDFS, the root class is rdf:resource for everything we describe whereas in OWL, the owl:Thing class is the root of all classes.
1 1 "http://www.w3.org/2001/XMLSchema#String"/> has booktitle Title of a book, 5
express that there must be some values of this property but atleast one value of this type has be owned by one Graduate student for example and owl:hasValue helps in constraining the values.
part of which is being cited. Also, there are certain cardinality constraints like minCardinality and maxCardinality to specify a range has publisher and owl:owned by property is used to define who owns which property. There are some richer properties which can be defined The publisher’s name. by OWL [14] like owl:ObjectProperty is used to connect a resource to another resource and owl:> OWL ontology can be validated using a validator as well. Some of the validators available are mindswap, wonderweb etc. has ISBN VII. XML VS RDF XML lets everyone create their own tags – hidden labels The International Standard such as or that annotate Web pages or sections of text on a Book Number. page. It also allows users to add arbitrary structure to their documents but says nothing about what the structures mean. object of an elementary sentence. These triples [11] can be written using XML tags [10]. In RDF, a document makes assertions that particular things like people, Web pages has price etc have properties such as ’is a sister of,’ ’is the author of’ having certain values in the form of another person or another Web page. Mostly, the > by URIs, which enables anyone to define a new concept, a But there could be a situation where two different databases as ISBN. So, there should be some mechanism in which a being used to mean the same thing. To handle this scenario, Ontologies comes into picture and it formally defines the re lations among terms, classes and properties. Hence, Semantic So, OWL helps in adding more expressiveness to the defined classes.
web helps in data integration across diverse systems easily and then allow us to query the system on the whole.
owl:allValuesFrom in terms of above example helps in ensuring that Advanced level book is owned by at least one Gradaute student. owl:some-ValuesFrom could be used to
VIII. A DVANTAGES OF S EMANTIC W EB In large scale system architectures there are often many component systems which cannot talk to one another and 6
involve a lot of effort to make the systems talk to one another. RDF helps in enabling systems to understand one anothers metadata. Metadata ontologies could also be used to glue various diverse systems and data models together.
There is a need to enrich available information with machineunderstandable semantics and Semantic Web will provide intelligent access to heterogeneous, distributed information, enabling software products to mediate between user needs. Currently, the web is mainly a collection of information but does not yet provide support in processing this information, i.e., in using the computer as a computational device. Web services can be accessed and executed via the web. However, all these service descriptions are based on semi-formal natural language descriptions. In order to bring them to their full potential, it is required to combine them with semantic web technology which will provide mechanization in service identification, configuration, comparison and combination.
IX. A PPLICATIONS •
•
•
Swoogle: Swoogle is a semantic web search engine and it has already been used in so many research projects and applications. Swoogle’s Ontology Search interface allows a user to search for existing ontology documents distributed over the internet. Knowledge management: One very promising application area of semantic web technology is knowledge management. Traditional knowledge management [15] is facing new problems triggered by the web; information overload, inefficient keyword searching, heterogeneous information integration and geographically-distributed intranet problems. These problems could be tackled by using Semantic Web Technology. Web Services: We are at a stage where we need to produce active components that use the basic semantic web infrastructure to offer users intelligent services. Web services aim to support information access and e-business. Examples include UDDI, a repository for describing vendors, products and services. It uses WSDL [16] to describe its entries, and SOAP as a protocol to define how they can be accessed. None of these service description elements are based on semantic web technology currently thus requiring tremendous human effort to perform tasks like: searching for vendors, products and services; comparing and combining products etc. Semantic web-enabled services [17] can provide a higher level of service by automating many of these tasks.
R EFERENCES [1] G. Marks and M. Roantree, “Pattern based processing of xpath queries,” in IDEAS ’08: Proceedings of the 2008 international symposium on Database engineering & applications. New York, NY, USA: ACM, 2008, pp. 179–188. [2] W. W. W. Consortium, “Rdf/xml syntax specifications,” Website, 2004. [Online]. Available: http://www.w3.org/TR/rdf-syntax-grammar [3] P. Genev`es and N. Laya¨ıda, “A system for the static analysis of xpath,” ACM Trans. Inf. Syst., vol. 24, no. 4, pp. 475–502, 2006. [4] M. Benedikt and C. Koch, “Xpath leashed,” ACM Comput. Surv., vol. 41, no. 1, pp. 1–54, 2008. [5] W. W. W. Consortium, “An xml query language,” Website, 2007. [Online]. Available: http://www.w3.org/TR/xquery [6] ——, “Xforms,” Website, 2007. [Online]. Available: http://www.w3. org/TR/xforms [7] I. D. Works, “Why xforms?” website, 2006. [Online]. Available: http://www.ibm.com/developerworks/library/x-xformswhy.html [8] J. Sim´eon and P. Wadler, “The essence of xml,” in POPL ’03: Proceedings of the 30th ACM SIGPLAN-SIGACT symposium on Principles of programming languages. New York, NY, USA: ACM, 2003, pp. 1–13. [9] A. Renear, D. Dubin, and C. M. Sperberg-McQueen, “Towards a semantics for xml markup,” in DocEng ’02: Proceedings of the 2002 ACM symposium on Document engineering. New York, NY, USA: ACM, 2002, pp. 119–126. [10] B. Linse and A. Schroeder, “Beyond xml and rdf: the versatile web query language xcerpt,” in WWW ’06: Proceedings of the 15th international conference on World Wide Web. New York, NY, USA: ACM, 2006, pp. 1053–1054. [11] J. J. Carroll and P. Stickler, “Rdf triples in xml,” in WWW Alt. ’04: Proceedings of the 13th international World Wide Web conference on Alternate track papers & posters. New York, NY, USA: ACM, 2004, pp. 412–413. [12] W. W. W. Consortium, “Resource description framework,” Website, 2009. [Online]. Available: http://www.w3.org/RDF [13] I. Horrocks and P. F. Patel-Schneider, “A proposal for an owl rules language,” in WWW ’04: Proceedings of the 13th international conference on World Wide Web. New York, NY, USA: ACM, 2004, pp. 723–731. [14] W. W. W. Consortium, “Semantic web activity,” Website, 2009. [Online]. Available: http://www.w3.org/2001/sw [15] B. Antunes, N. Seco, and P. Gomes, “Knowledge management using semantic web technologies: an application in software development,” in K-CAP ’07: Proceedings of the 4th international conference on Knowledge capture. New York, NY, USA: ACM, 2007, pp. 187–188. [16] D. Oberle, S. Staab, R. Studer, and R. Volz, “Supporting application development in the semantic web,” ACM Trans. Internet Technol., vol. 5, no. 2, pp. 328–358, 2005. [17] X. Wang, T. Vitvar, M. Hauswirth, and D. Foxvog, “Building application ontologies from descriptions of semantic web services,” in WI ’07: Proceedings of the IEEE/WIC/ACM International Conference on Web Intelligence. Washington, DC, USA: IEEE Computer Society, 2007, pp. 337–343.
X. R ELATED R ESEARCH There is an on ongoing work in the fields of knowledge management and electronic commerce. There is also a study going on the semantic web-enabled web services which will help to bring the semantic web to its full potential. There is a recent study being done by SWAP [17] demonstrating that the power of Peer-to-Peer computing and the Semantic Web can actually be combined to support decentralized environments where participants can maintain individual views of the world, while sharing knowledge in ways such that administration efforts are low but knowledge sharing and finding is easy. Emergent semantics extracts shared ontologies for sets of individuals or groups of people. The study depicts that Intelligent tools will use such definitions to ensure that knowledge will be appropriately structured, so that it can be easily refound. XI. C ONCLUSIONS The easy information access based on the success of the web has made it increasingly difficult to find, present and maintain the information required by a wide variety of users. 7
