4,765 research outputs found
Two Decades of Maude
This paper is a tribute to JosĂ© Meseguer, from the rest of us in the Maude team, reviewing the past, the present, and the future of the language and system with which we have been working for around two decades under his leadership. After reviewing the origins and the language's main features, we present the latest additions to the language and some features currently under development. This paper is not an introduction to Maude, and some familiarity with it and with rewriting logic are indeed assumed.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech
Ontology-Based Data Access and Integration
An ontology-based data integration (OBDI) system is an information management system consisting of three components: an ontology, a set of data sources, and the mapping between the two. The ontology is a conceptual, formal description of the domain of interest to a given organization (or a community of users), expressed in terms of relevant concepts, attributes of concepts, relationships between concepts, and logical assertions characterizing the domain knowledge. The data sources are the repositories accessible by the organization where data concerning the domain are stored. In the general case, such repositories are numerous, heterogeneous, each one managed and maintained independently from the others. The mapping is a precise specification of the correspondence between the data contained in the data sources and the elements of the ontology. The main purpose of an OBDI system is to allow information consumers to query the data using the elements in the ontology as predicates.
In the special case where the organization manages a single data source, the term ontology-based data access (ODBA) system is used
Multi-Paradigm Reasoning for Access to Heterogeneous GIS
Accessing and querying geographical data in a uniform way has become easier in recent years. Emerging standards like WFS turn
the web into a geospatial web services enabled place. Mediation
architectures like VirGIS overcome syntactical and semantical heterogeneity
between several distributed sources. On mobile devices,
however, this kind of solution is not suitable, due to limitations,
mostly regarding bandwidth, computation power, and available storage
space. The aim of this paper is to present a solution for providing
powerful reasoning mechanisms accessible from mobile applications
and involving data from several heterogeneous sources.
By adapting contents to time and location, mobile web information
systems can not only increase the value and suitability of the
service itself, but can substantially reduce the amount of data delivered
to users. Because many problems pertain to infrastructures
and transportation in general and to way finding in particular, one
cornerstone of the architecture is higher level reasoning on graph
networks with the Multi-Paradigm Location Language MPLL. A
mediation architecture is used as a âgraph providerâ in order to
transfer the load of computation to the best suited component â
graph construction and transformation for example being heavy on
resources. Reasoning in general can be conducted either near the
âsourceâ or near the end user, depending on the specific use case.
The concepts underlying the proposal described in this paper are
illustrated by a typical and concrete scenario for web applications
Implementing OBDA for an end-user query answering service on an educational ontology
In the age where productivity of society is no longer defined by the amount of information
generated, but from the quality and assertiveness that a set of data may potentially hold,
the right questions to do depends on the semantic awareness capability that an
information system could evolve into. To address this challenge, in the last decade,
exhaustive research has been done in the Ontology Based Data Access (OBDA)
paradigm.
A conspectus of the most promising technologies with data integration capabilities and
the foundations where they rely are documented in this memory as a point of reference
for choosing tools that supports the incorporation of a conceptual model under a OBDA
method. The present study provides a practical approach for implementing an ontology
based data access service, to educational context users of a Learning Analytics initiative,
by means of allowing them to formulate intuitive enquiries with a familiar domain
terminology on top of a Learning Management System. The ontology used was
completely transformed to semantic linked data standards and some data mappings for
testing were included. Semantic Linked Data technologies exposed in this document may
exert modernization to environments in which object oriented and relational paradigms
may propagate heterogeneous and contradictory requirements. Finally, to validate the
implementation, a set of queries were constructed emulating the most relevant dynamics
of the model regarding the dataset nature
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