Ontology is created based on information provided by domain experts and forms the basis for creating metadata. Ontology learning for the semantic web uni koblenzlandau. A linguistic ontology for the semantic web by scott farrar and terry langendoen 1. Introduction to the semantic web tutorial formal languages the degree of formality of ontology languages varies widely increased formality makes languages more amenable to machine processing e. Web ontology language owl semantics an owl ontology comprises. Ontology languages wide variety of languages for explicit specification logic based conceptual graphs ontology languages wide variety of languages for explicit specification logic based conceptual graphs syntactically higher order logics e. The semantic web is an extension of the world wide web through standards set by the world wide web consortium w3c. Prominent semantic web standards include rdf, which is used to describe relationships between entities, and owl, the ontology web language. Keywords ontology, semantic web, web languages, description languages, knowledge representation language, description logic. Specification did by resource description framework rdf 22. Available tools for ontology development are listed. Pdf introduction to semantic web ontology languages. Here we will make a first, fundamental distinction.
Finally, two additional languages are being built on. The approach also defines the meta languages required to create rdfs and rdf and to support extensions to both languages and their constructs. The definition 1 is the meaning in philosophy as we have discussed above, however it has many implications for the ai purposes. Owl is a computational logicbased language such that knowledge expressed in owl can be exploited by computer programs, e. Example 5 shows how to use the builtin functions of kaon2, such as adding or subtracting. We describe a uml meta modeling approach that defines five modeling layers and identify how rdfs and rdf as semantic web languages fit into the architecture. The architecture of the web depends on agreed standards and, recognising that an ontology language standard would be a prerequisite for the development of the semantic web, the world wide web consortium w3c set up a standardisation working group to develop a standard for a web ontology language. The owl languages are characterized by formal semantics. Ontologies have become a popular research topic in many communities. Although they are all xmlbased web languages, they still have some di. Formal foundation for ontology languages and tools, part 1. To make the web semantic, there is a need for new standard web ontology languages. Introduction to semantic web ontology languages citeseerx.
Ontology languages for the semantic web semantic scholar. A multiontology synthetic benchmark for the semantic web. Bootstrapping semantic web language using a uml meta. Example 3 shows how to retrieve axioms and navigate among them. The vision of a semantic web has recently drawn considerable attention, both from academia and industry. The semantic web relies heavily on the formal ontologies that structure underlying data for the purpose of comprehensive and transportable machine understanding. Html, and ontology markup language oml,5 whereas resource description framework rdf6 and rdf schema7 are languages created by world. The w3c web ontology language owl is a semantic web language. In this paper, we present a methodology based on the usage of protege 3. The lubm 7 is an example of a benchmark for semantic web knowledge. Constructing railway ontology using web ontology language. Hodge 2000 grouped typical information representation systems into three general categories.
Semantic web aims to make web content more accessible to automated processes adds semantic annotations to web resources ontologies provide vocabulary for annotations terms have well defined meaning owl ontology language based on description logic exploits results of basic research on complexity, reasoning, etc. The formal semantics provides an unambiguous interpretation of the descriptions. Historical background the term ontology comes from the field of philosophy that is concerned with the study of. Example 2 shows how to create an ontology, add several axioms, and save it into a file. Ontology languages for the semantic web ontology languages. Some of them are based on xml syntax, such as ontology exchange language xol,3 shoe4 which was previously based on html,and ontology markup language oml, 5 whereas resource description framework rdf6 and rdf schema7 are languages created by world wide web consortium w3c working groups. Example 4 shows how to add rules to an ontology, and how to run simple queries. Most of these languages are based on xml syntax, but with various terminologies and expressiveness. In this sense, the semantic web proposes the markup of content on the web using formal ontology that structure essential data for the purpose of comprehensive machine understanding. The definition 1 is the meaning in philosophy as we have discussed above, however it. The goal of the semantic web is to make internet data machinereadable. Using semantic web technologies to integrate the enterprise. Similarly, we create a web service metaontology based on the wsdl description, link concepts from the web service metaontology to those in the domain ontology, and use the oms edit service to augment the domain ontology with concepts then describes the web service 4.
A survey of web ontology languages and semantic web services. Description logic concepts fully into the semantic web. Semantic web ontology languages like owl 5, 9 these plugins implement the respective protocols and lift the mentioned learning management platforms to adaptive systems 39,57,114,115. Web content consists mainly of distributed hypertext and hypermedia, and is accessed via a combination of keyword based search and link navigation. Introduction the goal of an ontology is to achieve a common and shared knowledge that can be transmitted between people and between application systems 19. The aim of this chapter is to give a general introduction to some of the ontology languages that play a prominent role on the semantic web. Browse other questions tagged semanticweb ontology or ask your own question.
In this paper, we describe what description logics are and what they can do for the semantic web. Ontology and ontological systems for semantic webs in. Rdf is the format semantic technology uses to store data on the semantic web or in a semantic graph database. For example, if we decide to create attribute color as a global attribute, it will be applied to all concepts in the ontology.
Owl has more facilities for expressing meaning and semantics than xml, rdf, and rdfs, and thus owl goes beyond these languages in its ability to represent machine interpretable content on the web. The main standards that semantic technology builds on are the rdf resource description framework, sparql sparql protocol and rdf query language and, optionally, owl web ontology language. What is ontology introduction to ontologies and semantic. Ontology and the semantic web strive to express and enable semantic relations among represented entities. Semanticintelligent web, ontologies, ontology building tools, protege 3.
The modern web combines existing web technologies with knowledge representation formalisms. A multiontology synthetic benchmark 3 2 related work as mentioned before, except our previous work in 2, there is seldom related work similar to our multiontology semantic web benchmark system. This is the vision of semantic web to have meta information about every possible entities and create meta information following certain controlled vocabularies and logics referred to as ontology. Machine learning methods of mapping semantic web ontologies. Web schema languages existing web languages extended to facilitate content description xml xml schema xmls rdf rdf schema rdfs xmls not an ontology language changes format of dtds document schemas to be xml adds an extensible type hierarchy. Ontology learning for the semantic web university of georgia. They are used in agent systems, knowledge management systems, and ecommerce platforms. Introduction to semantic web ontology languages 5 maher is an instance of the professor class, then in any possible situation it is necessarily true that michael maher is an academic sta. If the semantic web vision 1 is to be realized, a sound and principled means of representing and reasoning with uncertainty will be required. Semantic web technology relies on ontology as a tool for modelling an abstract view of the real world and contextual semantic analysis of documents2. Pdf ontology languages for the semantic web researchgate.
Ontology languages for the semantic web intelligent systems, ieee. Pdf web ontology language editors for semantic web a. Description logics are often named as one of the tools that can support the semantic web and thus help to make this vision reality. Semantic web web of things processed by machines search in not based on word matching but on related. The world wide web consortium w3c created the webontology working group. They can also generate natural language, integrate intelligent information, provide semanticbased access to the internet, and extract information from texts in. In this section some recent ontology languages, particularly useful for the semantic web, are presented, namely, the extended markup language, the resource description framework, the knowledge annotation initiative, the simple html ontology extensions, the ontology interchange language, and the darpa agent markup language. The web ontology language owl is a family of knowledge representation languages for. Ontology languages for the semantic web open university. Description logics as ontology languages for the semantic. In recent years, several markup languages have been developed for realizing the semantic web. The aim of this chapter is to give a general introduction to some of the ontology languages that play a prominent role on the semantic web, and to discuss the formal foundations of these languages. A survey of web ontology languages and semantic web. A key challenge in building the semantic web, one that has received relatively little attention, is nding semantic mappings among the ontologies.
Introduction to semantic web ontology languages department of. The degree of formality of ontology languages varies widely increased formality makes languages more amenable to machine processing e. How ontologies benefit enterprise applications semantic web. It contributes several mechanisms that can be used to classify information and characterize. Description logics as ontology languages for the semantic web. Introduction the world wide web has the potential to become a primary source for storing and accessing linguistic data, including data of the sort that are routinely collected by. Ontology languages for the semantic web article pdf available in intelligent systems, ieee 171. Web ontology language owl world wide web consortium. The ontology web language owl is a set of markup languages which are designed for use by applications that need to process the content of information instead of just presenting information to humans the owl ontology describe the hierarchical organization of ideas in a domain, in a way that can be parsed and understood by software. Xml, rdf and owl are some of the languages which are used to represent ontology. The construction of these languages is evolving according to a layered approach to language development, in particular at the level of the ontology vocabulary fig. Ontologies are a formal way to describe taxonomies and classification networks, essentially defining the structure of knowledge for various domains.
A comparative study of ontology building tools in semantic. The need for knowledge preservation and representation, ontology construction methodology are briefly described. Having large amounts of linguistic data on the web will give. To enable the encoding of semantics with the data, technologies such as resource description framework rdf 2 and web ontology language owl 3 are used. The w3c web ontology language owl is a semantic web language designed to represent rich and complex knowledge about things, groups of things, and relations between things. Ontology is a body of knowledge describing some domain, typically common sense knowledge domain. Webbased ontology languages and its description logics 1. They can be applied to any concept in the ontology.
The lifecycle of ontology over the semantic web involves different techniques, protege 4. Introduction semantic web 1 is intended to guide the current web to a place where it is more useful for human consumption. On the syntactical level, standardization is an important topic. The web ontology language owl is a family of knowledge representation languages for authoring ontologies. The semantic web is representation of the language. Semantic web, and to discuss the formal foundations of these languages. Earlier research on ontology design methodologies shows that manual construction of ontology is a complex process and it is very hard for a designer to develop a consistent ontology. However, not only are ontologies useful for applications in which. Therefore, choosing a language for building an ontology is the main step.
We will describe some salient features of two systems. The semantic web ontology learning for the semantic web alexander maedche and steffen staab, university of karlsruhe the semantic web relies heavily on formal ontologies to structure data for comprehensive and transportable machine understanding. Web ontology languages will be the main carriers of the information that we will want to share and integrate. The main point of choosing language to represent ontology is based mainly on what the ontology will. The owl ontology describe the hierarchical organization of ideas in a domain, in a way that can be parsed and understood by software. Entities are identified using uris to work in a web setting axioms.
The most recent and best known and most frequently used is owl. Wide variety of languages for explicit specification. In fact, ontology is a main component of this research. There are now standard languages and a variety of commercial and open source tools for creating and working with ontologies. Ontology is an explicit specification of conceptualization.
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