Search results for "Web"
showing 10 items of 2018 documents
From Databases to Ontologies
2009
This chapter introduces the UML profile for OWL as an essential instrument for bridging the gap between the legacy relational databases and OWL ontologies. We address one of the long-standing relational database design problems where initial conceptual model (a semantically clear domain conceptualization ontology) gets “lost” during conversion into the normalized database schema. The problem is that such “loss” makes database inaccessible for direct query by domain experts familiar with the conceptual model only. This problem can be avoided by exporting the database into RDF according to the original conceptual model (OWL ontology) and formulating semantically clear queries in SPARQL over t…
Advanced RDB-to-RDF/OWL Mapping Facilities in RDB2OWL
2011
We present advanced features of RDB2OWL mapping specification language that allows expressing RDB-to-RDF/OWL mappings in a concise and human comprehensible way. The RDB2OWL mappings can be regarded as documentation of the database-to-ontology relation. The RDB2OWL language uses the OWL ontology structure as a backbone for mapping specification by placing the database link information into the annotations for ontology classes and properties. Its features include reuse of database table key information, user defined scalar and aggregate functions, table-based functions and multiclass conceptualization that is essential to keep mappings compact in case when large tables are mapped onto several…
Meter for the Quantitative Analysis of Newspaper Sport Material
2016
This article presents a meter for the quantitative analysis of newspaper sport material. The meter makes it possible to measure and classify newspaper sport material in detail. The meter has three levels. The selected level depends on the research purpose and desired measurement accuracy. Measurement can focus on a certain level, or all levels can be used together. Individual variables can also be utilized at a certain level. The three levels with respective level units of observation are: 1) articles, photos, and graphics; 2) sets of articles; and 3) sets of data materials. The use of each level is presented in the article. The article also contains a summary of the newspaper sport materia…
Artificial learning approaches for the nextgeneration Web: Part I
2008
Resumen en: In this paper we present an ontology learning tool for assembling and visualizing ontology components from a specific domain for the semantic web. The fo...
Document Word Clouds: Visualising Web Documents as Tag Clouds to Aid Users in Relevance Decisions
2009
Περιέχει το πλήρες κείμενο Information Retrieval systems spend a great effort on determining the significant terms in a document. When, instead, a user is looking at a document he cannot benefit from such information. He has to read the text to understand which words are important. In this paper we take a look at the idea of enhancing the perception of web documents with visualisation techniques borrowed from the tag clouds of Web 2.0. Highlighting the important words in a document by using a larger font size allows to get a quick impression of the relevant concepts in a text. As this process does not depend on a user query it can also be used for explorative search. A user study showed, th…
Comprehension effects of signalling relationships between documents in search engines
2010
A key task for students learning about a complex topic from multiple documents on the web is to establish the existing rhetorical relations between the documents. Traditional search engines such as Google(R) display the search results in a listed format, without signalling any relationship between the documents retrieved. New search engines such as Kartoo(R) go a step further, displaying the results as a constellation of documents, in which the existing relations between pages are made explicit. This presentation format is based on previous studies of single-text comprehension, which demonstrate that providing a graphical overview of the text contents and their relation boosts readers' comp…
Export of Relational Databases to RDF Databases by Model Transformations
2011
The Semantic Web is a Web of Data. To fulfill this web with data we need methods how to transfer business data from existing relational databases. In most cases, textual mapping languages are used for the specification of correspondences between relational DB schema and OWL ontology. These languages generally are rather awkward and not well-suited for the specification of mappings in cases when there is a substantial semantic gap between the source ER schema and the target OWL ontology. At the same time specification of mappings is a classical use case for graphical model transformation languages. In our previous work [10] we have proposed a new, model transformation-based method for the sp…
A Semantic Model to Query Spatial–Temporal Data
2013
There is a growing need for the study of spatial–temporal objects and their relationships. A common approach for this task is the use of relational databases, which unfortunately do not allow inference. In this research, we introduce a new approach that uses the concept of a “continuum” together with ontologies and semantic Web technologies. The continuum allows us to define parent–child relationships between representations of objects. It also allows us to compare the evolution of two different objects and establish the relationships between them along time. Our approach is based on the four-dimensional fluent, which is extended to obtain spatial–temporal qualitative information from the a…
Active Learning System in the Context of the Social Semantic Web
2013
In this paper we present the concept and the implementation of an Active Semantic Learning System that takes advantage of the Social Semantic Web in order to deliver an efficient and personalized learning experience to the learner. Active participation of the learner is encouraged through the social learning approach and through techniques that adapt the learning content to learners' needs and preferences. The semantic layer allows us to define a common understanding of the data used to describe the objects in the learning system. The objects in the learning system are described using semantic web technologies. Domain ontologies and explicit logic rules are defined in order to allow data in…
Combining OWL Ontologies Using -Connections
2006
The standardization of the Web Ontology Language, OWL, leaves (at least) two crucial issues for Web-based ontologies unsatisfactorily resolved, namely how to represent and reason with multiple distinct, but linked ontologies, and how to enable effective knowledge reuse and sharing on the Semantic Web. In this paper, we present a solution for these fundamental problems based on ℇ-Connections. We aim to use ℇ-Connections to provide modelers with suitable means for developing Web ontologies in a modular way and to provide an alternative to the owl:imports construct. With such motivation, we present in this paper a syntactic and semantic extension of the Web Ontology language that covers ℇ-Conn…